Colonial waterbirdsas bioindicators

in China and PakistanContact Bulletin of the Partners

EU-INCO-DC Contract IC18-CT98-0294

No. 6 1 May 2001

DRAFT OF THE

Final Scientific Report

Environmental Contamination,and breeding and foraging ecology,

of selected colonial waterbirdsin China and Pakistan

This report summarizes the results obtained for the EU-INCO-DC project “Colonial waterbirds as bioindicators in China and Pakistan”. It is still in a draft stage, to be completed before the conclusion of the project.

This report aims to circulate information among the participants to the research Project, and to provide a basis for the dissemination of the results to any concerned audience. This material can be:

freely used by any Partner for results dissemination to any audience, e.g. managers, press, general public (take care, however, to make clear that these results are partial, do not present them as conclusive)

used for scientific publications (in journals, at meetings), but before submitting any publication you should re-analyze the original data, obtain the approval of all the persons involved in the particular part of the research you wish to publish, and obtain the approval of the Project coordinator

In any case, when you refer to these data, you must cite the Project name, the contract number, and the funding by the European Union.

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Index and Summaries

Introduction page 1

The INCO-DC project “Colonial waterbirds as bioindicators of contamination in selected wetlands of China and Pakistan” was funded by the European Union (Contract IC18-CT98-0294), and was accomplished from September 1998 to September 2001 by six partners:

Dipartimento Biologia Animale, Università di Pavia, Italy

Departament. de Biologia Animal, Universidad, Barcelona, Spain

Pakistan Agriculture Research Council, Islamabad, Pakistan

WWF-Pakistan, Karachi, Pakistan

Biological Resources Institute, Jiangxi Academy of Sciences, Nanchang, , P.R. China

Department of Soil Ecology and Environmental Science, Chinese Academy of Sciences, Nanjing, P.R. China

with collaborations by:

Dipartimento Chmica Farmaeutica, Università, Viale Taramelli, I-27100 Pavia, Italy

Dipartimento Chmica generale, Università, Viale Taramelli, I-27100 Pavia, Italy

Department Biology, Lanzhou University, Lanzohu 730000, PR China

1. Environmental contamination, and human health page 2

A dramatic increase in public concern about the state of the environment has occurred in recent decades, in relation to a growing evidence that pollution has caused severe environmental degradation. Nowadays, about 1000 new chemical compounds are being synthesized each year, and between 60.000 and 95.000 are in use. A solution to the problems posed by contamination must start from the monitoring of these substances in the environment. In order to monitor pollutants, their environmental consequences and to assess ecosystem health, we need to use effective bioindicators, i.e organisms that accumulate contaminants that are present only at trace levels, so as to allow pollutant detection earlier than would be possible from abiotic samples.

As coastal and inland wetlands in Pakistan and China are subject to increasing pollution from industrial, urban and agricultural sources, there is a growing urgency to monitor contaminant levels, to assess the effects of pollutants, and to evaluate the resilience of these wetlands to pollution. The approach of our study focused on the use of colonial waterbirds as bioindicators of environmental contamination and other ecosystem changes. While a pletora of studies about contamination exists for America and Europe, very few studies exist for Asia. This research project aimed to ascertain the levels of the most widespread contaminants with long term persistence in some environments of China and of Pakistan.

The general objective was to assess pollutant levels and effects, using egrets and herons (colonial waterbirds of the Family Ardeidae) as bioindicators. We considered the most widespread contaminants with long term persistence: inorganic elements, particularly heavy metals and other elements of environmental concern

(Cd, Cr, Hg, Pb, Cu, Fe, Mn, As, Ag, Br, Co, Ce, La, Ni, Sc, Se, Zn) DDT and derivates other organochlorines (HCH+HCB, -HCH, -HCH, -HCH, heptachlor-epoxide -

endosulfan) polychlorinated biphenyls (PCBs)

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Since biomonitoring programs are most effective when they use a combination of indicators, at different levels of organization, our research program included the study of: eggs: contamination by organic compounds, as indicator of environmental contamination feathers: contamination by trace elements, as indicator of environmental contamination eggshell thickness and haemathological variables, as indicators of contaminants effects breeding success, as indicator of the present impact of contaminants breeding population size, as indicator of the long-term impact of contaminants contamination in prey of the egrets, as indicator of the contamination of particular habitats contamination of the sediments, as indicator of long-term contamination.

The results may indicate the level of pollution in the populations and ecosystems studied, highlight potential threats to human health, and provide valuable baseline data for comparison with future conditions in these ecosystems and elsewhere in Asia. The outputs will be useful for management of these important wetlands, for national policy formulation for pollution control and wetland conservation, and for the strengthening of pollution control regulations.

Specific objectives were: to infer exposure of Little Egrets to pollutants and the general bioavailability of pollutants

to identify whether concentrations of contaminants found, and any other ecosystem changes observed, are at levels associated with adverse effects on reproduction

to disseminate the results among environmental toxicologists and other scientists, ecosystem managers, environmental policy formulators and legislators.

We summarize here the results of the ecological studies, sample collection and chemical analysis. The ecological data, besides their own biological interest, provide a background information for the interpretation of the contamination levels. Contamination data show that concentration levels are generally lower than the threshold known to harm wildlife, both for metals and other elements, and for organic compounds, with some exceptions. These results are mostly welcomed, in that they testify a reduced environmental contamination.

2. Study areas page 10

For each country, we selected one wetland exposed to industrial-urban pollution, one to agricultural pollution, and one thought to be relatively unpolluted , on the basis of the presence of breeding colonies of egrets and herons, of their national and global importance, and of their various exposure to contamination1) Poyang Lake, Jiangxi, China. The largest freshwater lake in China, and the most important

site for waterfowl; a NEPA nature reserve; expected to be free of pollution.2) Tai Lake, Jiangsu Province, China. One of the largest lakes, in a highly productive area,

expected to be subject to serious pollution from agriculture and industry.3) Pearl River Delta and Coastal Area, Guangdong, China, a wide area, expected to be subject

to urban-industrial pollution4) Haleji Lake, Sindh Province, Pakistan, a freshwater lake, with associated marshes and

adjacent brackish seepage lagoons, expected to be relatively unpolluted5) Taunsa Barrage, Punjab Province, Pakistan, a storage reservoir behind a barrage on the

River Indus, expected to be subject to pollution from agriculture6) Karachi Harbour, Pakistan, tidal creeks, mangrove swamps and intertidal mudflats,

expected to be subject to considerable urban and industrial pollution

3. Methods for sample collection and for ecological studies page 14

Our main study species was the Little Egret Egretta garzetta, as monitor of contamination. For the ecological data however, we decided to consider all the other herons and egrets breeding in the same colonies, or foraging in the same wetlands, because this could be done with very little additional effort, but on the other hand it would greatly increase the completeness of the study. The collection and analysis of contamination samples remained restricted to the Little Egret, owing

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to the high cost of the chemical analyses. In some cases however, Little Egrets were too scarce to provide sufficient samples, and we were forced to shift to the most similar species (the Intermediate Egret, or theCattle Egret) as sample species.

During May and June 1999, teams of Asian plus European researchers worked jointly in the Haleji and in the Poyang study areas. This joint work was also intended as training, so as to ensure that all the researchers adopt exactly the same techniques. During May and June 2000, joint Asian-European teams worked in the remaining 4 study areas.

We standardized the field methods (collection of ecological records and of samples for chemical analysis), in order to ease the comparison of the different study areas. A booklet “Workplan and methods for Ecological Fieldwork & Sample Collection” was distributed to each participant. However, complete ecological records were obtained only in a part of the study areas, because of local constraints.

The ecological records included: Locate and census all waterbird colonies within each study area of 200-500 km P

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Breeding uccess, recorded for a sample of nests in one focal colony of each study area Prey of the chicks at the focal colony Foraging habitats used by the adults within a 10 km radius circle around the focal colony Prey biomass in rice paddies Feeding success and prey type of the foraging adults

We collected the following materials for chemical analysis: Eggs from different clutches. Feathers.of chicks from the same nests from which the eggs had been sampled. Prey of the chicks Sediments in the different foraging habitats used by the egrets

In addition, eggshell thickness was measured, and blood slides were obtained from the chicks. Eggshell thickness and haematological variables can be related to contamination.

4. Breeding and foraging ecology of egrets and herons at the Poyang Lakestudy area,China page 19

Population. Eight colonies were located and censused, within a study area of approximately 120 by 50 km Census of the nests. The impression is that the density and size of the colonies within the Poyang lake area is representative of the situation in the whole region. The breeding population is therefore very large, due to the wide surfaces of aquatic habitats, particularly rice paddies, that herons can exploit for foraging.

Breeding success. The breeding success of each species can be considered normal, and even higher, compared to the literature data. This high success preliminarily suggests that no adverse agent (e.g. contaminants) is affecting reproduction in this study area.

Prey. The main prey type was fish for every bird species. Shrimps, frogs and tadpoles appear in the diet in decreasing importance

Foraging habitats. The distribution of the foraging herons shows that Little, Intermediate, and Cattle egrets, and Chinese Pond Herons, forage mostly (for >80% ) on rice paddies. On the other hand, Great White Egrets forages with almost equal frequency in lakes, ponds, and rice paddies, while Night Herons forage mostly in lakes and rivers. Since most Little Egret foraged in rice fields, most sediment samples were collected there.

5. Ecology of egrets and herons at the Tai Lake study area, China page 26

Taihu region is one of the most productive areas for agriculture, and one of the most economically developed of China. Rice fields account for 90% of total farmland, and the water surface takes 45% of land. With the rapid economic growth since late ‘70s, water and soil pollution from industry,

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agriculture and urban waste has been increasing significantly. Therefore, there is a growing urgency to monitor contaminant levels in water and soil, and to assess the effects of pollutants to human and ecosystem health.

Population. Five heronries were found in the area. The Wuxi colony was selected as main study area, because of its dense population, species, accessibility, and highly exposed to soil and water pollution from agriculture and industries. The Wuxi colony was very large, with 9700 nests estimated in 1999, and 36400 nests in 2000.

Breeding Success. The breeding success of Night Heron and Little Egret could be considered normal, and even slightly higher for Little Egret, compared to the literature data (see Table 3.1). This suggests that no adverse agent (e.g. contaminants) was severely affecting bird reproduction in this study area.

Prey. The main prey type was fish, that accounted for 100% of the diet of Little Egret chicks, and for 95% of the diet of Night Heron chicks, that also received small amounts of frogs, crustaceans and mammals.

Foraging Habitats. The distribution of the foraging herons and egrets among the available habitats showed that most Little Egrets, Night Herons, and Chinese Pond Herons, foraged on fish ponds and on lake shores. The Night herons exploited the open waters of the lake as well. The scarce use of the rice fields is due to their relatively small surface within the study area. On the other hand, fish ponds were intensely used, presumably because they are abundant around the colony, and contain abundant food resources.

6. Breeding and foraging ecology of egrets and herons at the Guandong study area, China page 31

TO BE DONE BY DAI AND RUIZ

7. Breeding and foraging ecology of egrets and herons at Haleji study area, Pakistan page 32

Foraging habitats. We identifyed a total of 15 feeding areas within the Haleji lake, that is surrounded by arid dry lands, where no suitable place for herons feeding activity is available. The dominant species was by far the Intermediate egret, the other species being more than one order of magnitude below it.

Foraging ecology. The Intermediate and the Little egret used areas where water depth covered between 15 to 45 % of the leg length. Little Egrets tended to change feeding area more frequently than Intermediate Egrets. The foraging behavior of the two egrets was similar.

Diet. The diet of Intermediate Egret chicks was analysed through the chick regurgitates The most important prey in number were Caridean shrimps, followed by fish, the other prey being consumed only in small amounts. In biomass, fish was the most important prey followed by Caridean shrimps.

8. Breeding and foraging ecology of egrets and herons at Taunsa study area, Pakistan page 41

Population. Two heron colonies were present in 2000: the smaller colony was chosen as the focal ones for study, because of its accessibility. A second, large but inaccessible colony was located in a large reed bed.

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Breeding Success. The breeding success of the Little Egret was relatively low, i.e. toward the lower end of the range of values found in literature, and this may be due either to unfavorable environmental conditions, e.g. food scarcity, or to the effect of contaminants.

Foraging habitats. A variety of habitats was used for foraging by all the species of egrets and herons. Cattle Egrets used dry lands more than all the others, as it is usual for this species. The limited use of the rice paddies is due to the fact that they were flooded only during the last part of the survey.

9. Breeding and foraging ecology of egrets and herons at Karachi study area, Pakistan page 46

Population. Only one egret colony, with 145 nests, was present within this study area, and for a radius of at least 20 km.

Breeding Success. Breeding success, studied in all the nests that could be found in the colony, all belonging to the dark morph of the Little Egret, was low, i.e. toward the lower end of the range of values found in literature for different locations and years. This relatively low breeding success may be due either to unfavorable environmental conditions, e.g. food scarcity, or to the effect of contaminants.

Foraging habitats. The egrets foraged mostly on the surfaces of mud exposed at low tide, and with lesser frequency on the banks of large canals that connected the lagoon to the sea. The Intermediate egrets and the Indian Pond Heron foraged mostly on the same habitats.

Prey. All the prey items, collected throughout the study period, were small fish (Liza abu, Perciformes).

10. Heavy metal contamination in the samples from China page 49

Analytical Methods. Two analytical techniques were used for all the sample materials, that were split in two parts of similar amounts, whenever possible: Atomic Adsorption Spectrophotometry (AAS) for cadmium, mercury and lead, and Neutronic Activation Analysis (NAA) for the remaining elements. The results summarised below, are complete for NNA, but include only about one half of the results of AAS analysis, that are still in progress.

Contamination level in the samples. In eggs, here were significant differences in mercury, arsenic, bromine, cobalt, cesium, scandium, selenium and zinc concentration between locations. The highest levels of mercury, cobalt, cesium, scandium and zinc occurred at Poyang Lake, while the highest levels of selenium, arsenic and bromine occurred at the Pearl River Delta. The differences, however, were small, except for zinc, and in general the values were relatively low.

In feathers, there were significant differences in silver, cobalt, cesium, scandium concentration between locations. The highest levels of cobalt e scandium occurred at the Pearl River Delta, the highest levels of cesium occurred at Poyang Lake and those of silver occurred at Tai Lake. Again, these differences were not small, except for cobalt, and the values relatively low.

In prey, there were significant differences in cobalt, cesium, scandium and zinc concentration between locations. The highest levels of cobalt, cesium, scandium occurred in the prey from Poyang Lake, while the highest levels of zinc occurred at Tai Lake, and again the differences were not great and the values very low.

In sediments, there were significant differences in chromium, cesium, selenium and zinc concentration between locations. The lowest levels of chromium occurred in Pearl River Delta samples, and the values for Poyang Lake and Tai Lake were much higher and very similar. The lowest values of cesium and zinc occurred in the Poyang Lake samples and the values for Pearl River Delta and Tai Lake were much higher and very similar. The lowest values of selenium occurred in Tai Lake and the concentration for Pearl River Delta and Poyang Lake were much higher and very similar.

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Evaluation of environmental contamination levels. We discuss the concentration levels, in relation to the thresholds that may be harmful to the birds, and that may indicate alarming environmental pollution, and we evaluate the concentration levels in China in relation to the levels found in other regions. However, the samples analyzed so far, owing to incomplete analysis by AAS, in some cases are still too few to be meaningful.

Cadmium. Concentrations previously found in healthy populations of egrets and of herons in other regions were similar to those found in China.

Lead. The levels found in eggs are lower than those previously found in egrets and herons elsewhere. Much higher levels were found in egret feathers near Hong Kong in the early nineties.

Mercury. The concentrations found in fish are lower or similar to those found elsewhere, and are gnerraly below the threshold for toxic effects.

Arsenic. Arsenic has been rarely determined in aquatic animals, and comparative data are few. The concentrations found in tadpoles were rather high.

Copper, manganese, and iron. These elements are essential for life, and only become toxic at high doses. No data have been published about these metals in eggs or feathers of wild bird populations.

Selenium. The concentrations found in eggs are rather high, but still lower than the threshold affecting bird reproduction.

Zinc. Althought there were significant differences among the colony sites, the values we found in eggs and feathers can be considered normal.

11. Heavy metal contamination in the samples from Pakistan page 64

The analytical techniques were the same as described about heavy metal contamination in China. The results include only a half of the results of AAS analysis, that are still in progress.

Contamination level in the samples. In eggs, there were significant differences in the concentration of zinc, cadmium, and lead between locations, with the highest levels of zinc and cadmium in the samples from Haleji. However, the differences were limited, and the values were very low.

In feathers, t here were significant differences in bromine, cobalt, cesium and copper concentration between locations. The highest levels of bromine and cesium occurred at Karachi, the highest levels of cobalt at Taunsa, and those of copper at Haleji. High concentrations of iron were found in the samples from Karachi and Taunsa.

In prey, there were significant differences in chromium, mercury and lead concentration between the three location, and the highest levels occurred in the samples from Karachi.

In sediments, there were significant differences in bromine, cesium, lanthanium cadmium and mercury between the three study areas. The highest levels of bromine, cesium, cadmium and mercury occurred at Karachi and those of lanthanium at Taunsa.

Evaluation of environmental contamination levels. As for China, we discuss the concentration levels, in relation to the thresholds that may harm the birds, and that may indicate alarming pollution, and we evaluate the concentration levels in Pakistan in relation to those found in other regions. However, the samples analyzed so far, owing to incomplete analysis by AAS, in some cases are still too few to be meaningful.

Cadmium. Concentrations previously found in healthy populations of egrets and herons in other regions, were higher to those we found in Pakistan.

Lead. The levels found in eggs from Pakistan were lower than those previously found in egrets and herons elsewhere.

Mercury. The values found in fish from Karachi were below the concentration associated with sub-lethal or lethal toxic effects.

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Arsenic. It is a toxic, non-essential element, that has been rarely determined in aquatic animals. The concentrations found in prey samples may be considered rather high.

Selenium. The concentrations found in eggs are rather high, but still lower than threshold that may affect bird reproduction.

Zinc. The values we found in eggs and feathers can be considered normal.

12. Contamination by organic compounds in the samples from China page 77

Analytical methods. Chemical analyses were low. In prey, higher levels were found in fish and tadpoles. The highest levels were found in the sediments from Poyang Lake.

PCBs levels were higher in the eggs of egrets from Tai Lake, followed by egrets from Pear River delta and Poyang Lake. No PCBs were detected either in prey or in sediments at Poyang Lake. Only vertebrate samples from Tai Lake had significant levels of PCBs. These pollutants were detected in sediments from both Tai Lake and Pearl River Delta.

Pesticide pollutants were detected in all the eggs, both at Poyang Lake and at the Pearl River Delta. Only one egg from Tai Lake had levels of pollutants below the limit of detection. The most abundant pesticides were in all the cases DDTs, and in the Poyang and Pearl River Delta these were present exclusively as the pp’-DDE congener. The proportion of PCBs was highest at Tai Lake and Pearl River Delta than in Poyang Lake.

Comparison among study areas. To compare pollutant levels among different areas, only eggs of Little Egrets have been considered. Significant differences were found for HCB, HCH, and PCB levels, and for the ratios DDE/DDT, DDT/ TOTAL PESTICIDES, and DDTs/PCBs.

Evaluation of environmental contamination levels. HCB levels in the eggs from the three areas were significantly different, those collected at the Poyang Lake had much lower concentrations than those collected either at Tai Lake or at the Pearl River Delta, which in turn had similar values. The levels found in prey, are surprising at a first, since HCB is present in all prey from Poyang, but only in a few from Tai Lake. Furthermore, the levels at Poyang were higher than at Tai Lake. Sediments at Poyang presented detectable levels of HCB, and below the detection limit at the other two study areas, thus suggesting that HCB pollution is higher in the whole aquatic compartment (sediment and aquatic biota) at Poyang Lake, while it is higher for terrestrial secondary consumers at Tai Lake. Such a situation can only be explained by differences in recent inputs of this pollutant into the aquatic compartment, i.e., at Poyang Lake HCB should have been introduced more recently than at Tai Lake, where almost all the compound has been already transferred to the upper levels of the food chain.

For HCH, both the percentages of detection and the concentrations, were similar in eggs from Pearl River Delta and Tai Lake, and were significantly lower in eggs from the Poyang Lake, following a trend very similar to that obtained for HCB. For prey items, concentrations were quite similar between Poyang and Tai Lakes, but the percentages of detection were much higher at Tai Lake, indicating a more recent pollutant input. Therefore, the results obtained for eggs also agree with this scenario, since birds at Poyang presented lower levels, probably because they have had more time to metabolize and excrete these compounds since the last input in that ecosystem.

Cyclodienes levels were very low in eggs and sediments at the Poyang Lake, and weer absent from prey. This indicates a recent and localized source of pollution. Conversely, the levels at Tai Lake and Pearl River Delta are higher and much more widespread in eggs, indicating more generalized and ancient inputs.

DDT and derived compounds, which are the main indicators of pollution deriving from agriculture treatments, were widely distributed, and were detected in most samples of eggs, prey, and sediments. Levels in eggs from the three study areas did not differ. Therefore, the pollution by such compounds is old, intense, generalized and persistent. One sediment sample from Poyang Lake had extremely high levels of DDT, indicating a recent input of that pesticide in the ecosystem,

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despite that it was officially banned in China in 1982. Levels at Pearl River Delta were higher than at Tai Lake.

PCBs are the indicators of organochlorine pollution deriving from industrial were done using high resolution chromatography.

The compounds that were analysed include the following organochlorine that persist in the environment:

Hexachlorobenzene (HCB), a fungicide for seed grains and an industrial waste product.

Hexachlorocyclohexanes (HCHs), used on seed and livestock

Cyclodienes: Heptachlor and heptachlor epoxide, an insecticide primarily used to control soil pests

Endosulfan:an herbicied that however does not accumulate in warm-blooded animals.

Dichloro-Diphenil-Trichloroethanes (DDTs), with insecticidal properties, which came into wide agricultural use in the late 1940s, and that caused catastrophic population declines in certain bird species. It was used extensively in agriculture, but their use has been restricted in most countries, included Pakistan.

Polychlorinated Biphenils (PCBs), a group of synthetic chlorinated aromatic hydrocarbons, used since 1930 in commercial products including heat transfer agents, lubricants, dielectric agents, flame retardants, plasticizers, and waterproofing materials. Environmental contamination has resulted from several sources including.

Contamination level in the samples. HCB has been detected in most egg samples, higher levels being found atTai Lake. HCB was present in all prey samples from Poyang Lake, but in a low number of prey samples from Tai Lake. For sediments, only those from the Poyang Lake had detectable quantities of HCB.

HCHs were detected in a high proportion of egg samples from Tai Lake and the Pearl River Delta, and in few eggs from the Poyang Lake. HCH concentrations in eggs form Tai Lake and Pearl River Delta were similar.

Cyclodienes. The eggs from Tai Lake and Pearl River Delta presented similar levels, and cyclodienes were detected in most samples, whereas they were found only in one egg from Poyang Lake and at a lower concentration. No cyclodienes were detected in prey at Poyang, but these compounds were present in almost all the prey collected at Tai Lake. For sediments, higher levels were found at Tai Lake, followed by those at Poyang Lake and at the Pearl River Delta.

DDTs and its metabolites. Total DDT levels were similar in the egret eggs from the three areas, being detected in almost all the samples. DDTs were detected also in a high percentage of preys, higher levels being attained by vertebrates, fish and tadpoles. Except for one sample taken in a pond at Poyang Lake that exceeded 48 mg/kg, concentrations in the sediments sources. Significant differences were found in the levels of PCBs and in their occurrence among study areas. Their levels were very low in the eggs from Poyang, while atTaihu Lake the eggs had mean levels about 20 times higher than at Poyang and about double than at the Pearl River Delta. The same trends were observed for sediments and for prey.. Therefore, Tai Lake is confirmed as the area most affected by “industrial” pollution in China, among our three study areas.

The ratio DDT / PCB was similar for Tai Lake and the Pearl River Delta, whereas this ratio was much higher for Poyang Lake, thus indicating a clear predominance of agricultural vs. industrial pollutants in this last study area.

Comparison with Pakistan and with other regions.This comparison is based exclusively on pollution in eggs, since heterogeneity of prey and foraging areas precluded the use of other types of samples.

HCB were only detected in China and not in Pakistan. Levels in Little Egrets from the Danube Delta were much higher.

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HCH levels in eggs ranged from 10 ppb at Poyang, to 50 ppb at Haleji Lake, and in ascending order from low to high pollution were: Poyang - Taunsa – Pearl River Delta and Tai Lake – Haleji. Therefore, for such compounds the Poyang lake fits better the condition of low pollution area, than its corresponding area in Pakistan (Haleji Lake). In general, the levels were very low, and well below the dangerous exposure to the toxicant. This is also the case for all the other species of egrets analyzed in the other study areas, Karachi, Haleji, and Taunsa.

Cyclodienes. Since there are only data from our samples, comparison with other areas is precluded. The lower levels were found in the most natural areas in China (Poyang) and in Pakistan (Haleji). Intermediate levels were found at the two agriculture and industry polluted areas in China (Pearl River Delta and Tai Lake), and higher levels at the two study areas with intense agricultural (Taunsa) and industrial develoment (Karachi) in Pakistan. However, these levels are much lower than those reported to have effects in birds.

DDTs. Little Egrets from the three areas in China had similar levels of these pollutants, but they reach the highest levels in eggs from the supposed pristine area (Poyang Lake), which had levels about fivefold those of its counterpart in Pakistan (Haleji). Only the most DDT-polluted of our six study areas (Taunsa), showed higher average levels of DDTs than Poyang Lake. These levels are, however, below those reported from Europe and America. However, the levels reported for Little Egrets in Italy wer much lower. In any case, the levels in China and in Pakistan seem to be well below those having adverse effects on bird reproduction.

PCBs. Except from some samples at Karachi, the levels we found were low compared to literature data. Poyang and Haleji fitted well to their condition of pollution-free areas for these compounds, followed in order of increasing contamination, by Taunsa, Pearl River Delta, and Tai Lake. Levels in Tai Lake are similar to those found in Italy and in other parts of Europe and of America. The levels are much lower than those affecting embryo development or survival in different bird species.

Concluding remarks. In China, the Poyang Lake area is characterized by lower impact of HCBs, HCHs, Cyclodienes and PCBs, but had the highest average levels of DDT. Another characteristic of Poyang Lake samples was their heterogeneity, since the percentage of samples containing different organochlorine contaminants was very variable. This indicates that, even though Poyang Lake ecosystems had low levels of organochlorines, there are important local sources of pollution, some of them responsible of recent inputs.

At Tai Lake, the pollution was highest for PCBs, indicating that this area, and not the Pearl river Delta, is the one most affected by industrial pollution. Conversely, the levels of DDTs were somewhat higher at the Pearl River Delta. At both localities, the input of pollutants seem to be older, much more homogeneous (i.e. generalized) than at Poyang lake, as indicated by the percentage of samples having detectable levels of the different organochlorine contaminants. PCB and DDT excepted, these two areas showed homogeneous levels of pollutants.

In general, the levels found in the different areas included in this study are lower than those reported for Europe and north America, and below the observed ranges having adverse effects on bird reproduction or survival.

13. Contamination by organic compounds in samples from Pakistan page 96

The analytical techniques, and the compounds, were the same as described for China.

Contamination level in the samples. HCB levels in the eggs were relatively low, and were similar for Haleji and for Karachi, while levels from Taunsa were much lower. In both prey and sediments, HCB was only detected in samples from Haleji Lake.

HCHs were detected in most eggs, but they were almost undetectable in both prey and sediments. The highest value were found at Haleji.

Cyclodienes were almost absent from Haleji. Nevertheless, although at low levels, they were detected in egg samples from Taunsa and Karachi. Concentration in Little Egrets from the two

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latter areas were similar, but Cattle Egret from Taunsa had lower levels. Fish samples from Karachi had remarkably high concentrations. At Haleji the most abundant cyclodiene was α-endosulfan. In Taunsa, heptachlor epoxide reached higher concentrations than the other cyclodienes, whereas in Karachi the most abundant was β-endosulfan.

DDT compounds were found in all the egg samples. Mean levels were higher at Taunsa, followed by Karachi. Nevertheless, maximum values were found in Intermediate Egrets from Haleji. In prey, these compounds were not detected in all the samples, highest values being found in fish. Remarkably, no DDTs were detected in sediment samples from Taunsa.

PCB’s highest values were detected in the eggs from Karachi. Egret eggs from Taunsa had much lower concentrations, but above those from Haleji. Prey samples from different localities had similar PCB concentrations. In sediments, the higher values were recorded at Karachi. No PCBs were found in sediments from Haleji Lake.

Comparison among the three study areas. To compare different areas, only samples form Little Egrets were considered. Significant differences were found in the levels of HCB, DDTs, PCBs, and also in the ratio ppDDE/ TOTAL DDTs, and in the ratio DDTs/PCBs.

Evaluation of environmental contamination levels. There is no information about the levels or the impact of persistent organic pollutants in wetlands of Pakistan. Presently, pesticides in Pakistan are applied mostly to cotton fields, that are concentrated mainly in Punjab, Sindh, and to a lesser extent in Baluschistan. The pesticides in use are mostly insecticides. Pesticides are also applied to other crops, such as vegetables and fruit. Estimated consumption of pesticides in Pakistan ranged from 13,030 metric tons in 1990-91, to 30,471 metric tons in 1995-96. The results presented here constitute a first evaluation of the impact of several organochlorine pollutants.

At Haleji Lake, DDTs have been found been found in all the egg samples, and they are the pollutants which attain the highest concentration in eggs. Concentrations however, were lower or similar to those reported elsewhere for heron, and in most cases they lower than the levels reported to be detrimental to these birds. Nevertheless, the concentration in three eggs of Intermediate Egrets were above these levels, and therefore some birds are exposed to high DDTs levels, probably while feeding in agricultural areas or paddy fields. Eggshell of these eggs was thinner than in eggs with less DDT. The high DDE/DDTs ratio in the eggs suggests that exposure to DDT is recent. Other organochlorines in the eggs, HCHs, HCB and PCBs, are less abundant than DDTs, and appear in low concentration. Available data on HCH usage indicates a lower consumption of these pesticides in Pakistan compared to neighbouring countries like India or China. The fact that no HCH was detected in fish or sediments is in agreement with the findings of several authors, who reported a low accumulation of HCH in aquatic organisms and sediments in the tropics. The low levels of PCBs in the eggs at Haleji, and its absence from fish and from sediments, indicate a low industrial activity.

At Taunsa, the highest organochlorine levels in eggs corresponded to DDTs, mainly DDE that was found in all the samples, thus indicating a wide distribution. DDE is present in aquatic prey, fish and frogs, but not in insects sampled. The differences observed between Little and Cattle egrets at Taunsa are relatable to their feeding habits, since Little Egrets feed markedly on fish, while Cattle Egrets depend on terrestrial preys, such as including insects. Cyclodiene compounds were the second organochlorine pollutants in importance in the eggs, followed by PCBs and HCHs. The level of PCBs are generally low compared to literature data, and do not pose a threat to the birds.

At Karachi, the samples from the egrets showed high levels of several organochlorine pollutants, particularly PCBs and DDTs.. Nevertheless, none of the samples had concentrations above levels associated to risk. These compounds were detected also in the fish which constitute its prey. Within the sediments, mud has a much higher concentration compared to samples collected in the channel. PCBs are the organochlorines reaching the highest levels at Karachi. Their maximum concentrations are found in the eggs, and in lower amounts in prey and sediments. These pollutants were detected in all the eggs and prey samples, thus indicating a wide distribution of PCBs in the Karachi area, probably related to discharging of

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untreated sewage waters, both from industrial and domestic origin. The sensibility of birds to PCBs and their effects on bird reproduction are highly variable between species, but the levels of PCBs in eggs are lower than those reported to cause detrimental effects in other bird species. The levels of cyclodiene insecticides were also moderately high. These compounds were found in all the egg and n all the prey samples.

Concluding remarks. Overall, the results show that the egret eggs reflect well the expected differences in exposure to the different pollutants among the three study areas. Haleji Lake, selected as the natural area in Pakistan, showed significantly lower concentrations for cyclodienes, DDTs and PCBs than the other two areas. Taunsa is characterized by higher concentrations of cyclodienes and DDTs, with relatively low levels of PCBs. Karachi shows relatively high concentrations of cyclodienes and DDTs, and very high concentartions of PCBs, and it is the only area where such industrial organochlorines reach higher levels than the pesticide compounds.

In contrast, HCB levels, albeit very low in general, are significantly higher at Haleji, and smaller at Taunsa than at Karachi. Only at Haleji sediments and prey presented detectable levels of HCB, and this indicates a recent input.

The average DDTs levels were higher in the eggs at Taunsa and at Karachi, than at Haleji. It must be taken into account that Taunsa is a mainly agricultural area, which probably received high inputs of pesticides and of DDTs among them. On the other hand, Karachi lies at the end flow of the Indus, and receives water which has been used for municipal, agricultural, and industrial purposes. Moreover, none of the cities along the Indus River treat the water before discharging, thus agricultural pesticides may arrive with the water supply. The lack of farming activities around Haleji would result in lower levels of pesticides reaching these waters, and atmospheric transport would account for most of the DDT presence in the area.

For HCHs, no difference was found among the three study areas. It was shown that about 99,6% of HCHs applied to paddy fields in tropical agrosystems are volatilized to the atmosphere, and it was estimated that only 0,1% of the applied HCH was ultimately drained to the sea by the river. In spite of the recent use of HCH in some Southeastern Asian countries, the residue levels in fish are low, because of the rapid volatilisation of HCH at tropical latitudes.

14. Conclusions page 116

Contamination data show that concentration levels are generally lower than the threshold known to harm wildlife, both for metals and other elements, and for organic compounds, with some exceptions. These results are mostly welcomed, in that they testify a reduced environmental contamination.

15. References page 117

Appendix A. List of samples collected in China, and their content of metals page 127

Appendix B. List of samples collected in Pakistan, and their content of metals page 132

Appendix C. List of samples collected in China, and their content of organic contaminants page 136

Appendix D. List of samples collected in Pakistan, and their content of organic contaminants page 140

XII

Introduction

The INCO-DC project “Colonial waterbirds as bioindicators of contamination in selected wetlands of China and Pakistan” was funded by the European Union (Contract IC18-CT98-0294), and was accomplished from September 1998 to September 2001 by the six partners:

Dipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, ItalyMauro Fasola (e-mail TU fasola@ipv36.unipv.it) UT, project’s coordinator

Departament. de Biologia Animal, Avgda. Diagonal 645, 08028-Barcelona, SpainXavier Ruiz (e-mail xruiz@porthos.bio.ub.es), local coordinator

Pakistan Agriculture Research Council, P.O. Box 1031, Islamabad 45500, PakistanUmar Khan Baloch (e-mail ukbaloch@hotmail.com), local coordinator

WWF-Pakistan, 6th

Floor, Block 6, P.E.C.H.S Shahra-e-faisal, Karachi 75400, PakistanRahat Jabeen (e-mail wwfkhi@khi.compol.com, rahat@hotmail.com), local coordinator

Biological Resources Institute, Jiangxi Academy of Sciences, Nanchang, Jiangxi 330029, P.R. China

Dai Nianhua (e-mail nhdai@public.nc.jx.cn), local coordinator

Department of Soil Ecology and Environmental Science, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing 210008, P.R. China

Yuanhua Dong (e-mail yhdong@ns.issas.ac.cn), local coordinator

with collaboration by:

Dipartimento Chmica Farmaeutica, Università, Viale Taramelli, I-27100 Pavia, ItaliaCarlo Gandini (e-mail TU carga@unipv.it) UT , chemical analisys

Dipartimento Chmica generale, Università, Viale Taramelli, I-27100 Pavia, ItaliaEdoardo Orvini (e-mail orvini@chifis.unipv.it) , chemical analisys

Department Biology, Lanzhou University, Lanzohu 730000, PR ChinaYingmei Zhang (e mail TU pyk@lzu.edu.cn) UT, collaborator

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1.

Environmental contamination, and human health

Fasola MauroDipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

A dramatic increase in public awareness and concern about the state of the environment has occurred in recent decades, in relation to a growing evidence on the extent to which pollution has caused severe environmental degradation. The introduction of harmful substances into the environment has been shown to have many adverse effects on human health, agricultural productivity, and natural ecosystems, although it is surprising how resilient environmental systems are to the pollutant burden so far imposed to them. Pollution is one aspect of environmental degradation which arouses most interest, because it impacts directly upon people through effects on their health, food, cultural heritage and the countryside. The costs of these effects in the depreciation of resources, lost productivity and the need to clean up polluted environments are high, and are increasingly occupying the attention of governments around the world (Alloway & Ayres 1997).

Although cases of acute and overt pollution shock the public opinion, less appreciated but more important is the fact that most environments suffer from insidious chronic pollution. The effects of chronic pollution only become apparent after long exposure, e.g. in the case of people exposed to pollutants that may cause cancer 10 or 20 years later, or in the case of toxic effects in trees that appear after 20 years and are irreversible. For this reason, environmental monitoring is vitally important in detecting insidious pollution. An example of human health problem which is causing growing concern, is decline in male fertility in technologically advanced countries over recent decades. This is tought to be caused at least in part, by exposure to pollutants which have effects similar to female hormones. But exposure to these oestrogenic chemicals has probably occurred during the past decades, and the time lag for their effects to appear makes remediation difficult.

Pollution is the accumulation and adverse interaction of contaminants with the environment. A contaminant is any substance that occurs in the environment at least in part through human action, and that at the levels found, has deleterious effects on living organisms. Contaminants may result from natural processes, but presently the main concern is that human activities are increasing the amount of contaminants into the environment. The contaminants are released into environment, consisting of soil, surface waters, the atmosphere, and their living inhabitants, where they accumulate or undergo physical and chemical changes. Taken together, the way in which substances are added to the environment, the rate at which these wastes are added, and the subsequent changes that occur, determine the impact of the contaminant on the environment.

The modern types of contamination include several xenobiotic substances, compounds that are foreign to natural systems, and which are usually less subject to biodegradation, i.e. the breakdown of organic compounds by organisms, up to complete degradation and to mineralization. The problem with contaminants is exacerbated by the human population growth, and hence by the amount of toxic substances produced and released into the environment (Pepper et al. 1996). Environmental contamination with these substances may come from many sources:

air pollution, that may introduce metals into the environment, with the particulate matter produced by combustion

surface water pollution, through waste disposal

agricultural fertilizers, that contain the 16 elements essential for plant growth; but excess amounts of these elements may cause pollution

agricultural pesticides, which are essential to sustain productivity; however some of these pesticides, particularly chlorinated hydrocarbons, are very persistent and subject to bioaccumulation

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waste disposal

industrial processes, that may as a side effect disseminate an array of chemical elements and compounds, including metals, and polychlorobiphenils used for various processes.

Nowadays, about 1000 new chemical compounds are being synthesized each year, and between 60.000 and 95.000 chemicals are in current commercial use.

Substances may be toxic or non-toxic, but toxicity may depend on concentration above certain thresholds. Concerns about toxic substances in food and in the environment arose at the beginning of the twentieth century. The systematic study of toxic effects in laboratory animals began in the 1920s, but toxicology grew in importance especially after the 1940s, in relation to the development of industry and of evolved agriculture. One of the factors which led to a increase in environmental awareness and concern about pollution was the publication of certain inspiring books during the 1960s, like “Silent spring” by Rachel Carson in 1962. At the time this book was written, developments in plant breeding and pest control had boosted optimism in advanced countries, food production was increasing rapidly along with an exponential rise in the use of pesticides and fertilizers, and little attention was given to the consequences of their accumulation in the environment. The effects of pollutants on animals and humans include acute alteration of vital parameters, and subclinical, chronic effects that may impair their vitality and reproduction, like carcinogenesis, mutagenesis, teratogenesis, damage to the immune system, chromosomal abnormalities, modifications of enzymes function and of nervous transmission. Studies on birds had the merit of raising early alarms about the dangers posed by pollutants in the environment. Three main mechanisms of bird population decline in relation to contamination have emerged (Newton 1998). First, some contaminants cause directly deaths or breeding failures. Secondly, other contaminants act indirectly by reducing food supply. Thirdly, other chemicals can alter the physical or chemical structure of habitats, making them less suitable for certain species.

A solution to the problems posed by contamination must start from the monitoring of these substances in the environment, through the collection and analysis of samples.

While a pletora of studies about environmental contamination exists for America and Europe (summarized in books such as Alloway & Ayres 1993, Pepper et al. 1996, Beyer et al. 1996), comparatively very few studies exist for Asia: on birds of China (Burger & Gochfeld 1993, Jeng & Yang 1995) of Korea (Honda et al. 1986, Lee et al. 1989), of Russia (Lebedev et al. 1998); on other components of the environment of China (Chui et al.1991, Connell et al. 1998), of Korea (Jung & Thornton 1997), of Japan (Doi et al. 1984), of Iran (Sodergren et al. 1978), and of India (Ramesh et al. 1992); on humans of China (among others, Cai et al. 1995, Nordberg et al. 1997, Yang et al. 1994), of Japan (Fujiwara 1975, Ikeda 1992), and of India (Nair & Pillai 1992).

This research project aimed to ascertain the levels of the most widespread contaminants with long term persistence, heavy metals, chlorinated hydrocarbons, and polychlorobiphenils, in some environments of China and of Pakistan.

Birds as bioindicators

Toxicology studies the adverse effects of chemicals on the health of both humans and of all the components of the natural environment. Non-target organisms absorb contaminants through their food, but also through their skin and through inalation. If pesticides destroyed only the target pests and then quickly broke down to harmless by-products, problems for their use would be minimal. But most pesticides are non-specific, and kill a wide range of organisms. Secondly, while some broke down rapidly, others last for weeks, months or even years in animal bodies or in the physical environment. Thirdly, some pesticides accumulate in body fat and readily pass from prey to predator, causing secondary poisoning, or even pass along several steps in a food-chain, affecting animals far removed in trophic position from the target pest. In addition, by contaminating air and water, some contaminants can reach areas and affect organisms far removed from points of application, as shown by the famous examples of DDT present in penguins of the Antarctic.

Several authors have pointed to the use of animals to monitor changes in the aquatic or terrestrial environments. Although the use of sedentary invertebrates has been stressed, some characteristics of birds make them very useful. They are able to integrate pollutant levels in the whole ecosystem or over a broad area and thus, less sampling would be necessary. Also, since they are usually placed at high nodes in the

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food webs they can reflect pollutant hazards to humans (Furness, 1993). Nevertheless, biomonitoring programmes have been proven to be more satisfactory when combining biological indicators (at different levels) along with chemical and/or physical ones.

Throughout the world, birds are affected by environmental contaminants including organochlorine compounds, organophosphorous insectidicdes, trace elements, and petroleum. Well known cases of population decline due to accumulation of DDT regard some raptors, the Peregrine falcon Falco peregrinus, the Sparrowhawk Accipiter nisus and the Osprey Pandion haliaetus in Europe, and various fish-eating and seed-eating birds. Some of these species have now recovered, 20 years after the ban of DDT use in Europe.

Heavy metals, and organic pesticides, are among the major ecotoxicants for which we need the earliest possible indications of rising levels, both at local and at global scale. The need to determine the exposure to these pollutants, and to evaluate their effects, has led to the development of numerous monitoring programs. As it is not possible to measure all ecosystem functions and properties, bioindicators are increasingly used to monitor environmental quality and ecosystem-level change. A bioindicator may be defined as an organismic property so strictly associated with particular environmental conditions, that its presence is indicative of the existence of these conditions.

In order to monitor the abundance of persistent pollutants, their environmental consequences and to assess ecosystem health, we need to use effective bioindicators, i.e organisms that accumulate contaminants that may be present only at trace levels, so as to allow pollutant detection earlier than would be possible from abiotic samples (Pedersen and Myklebust 1993). Bioaccumulated contaminants integrate and reflect both chronic and intermittent exposure, which could be missed in periodic sampling of abiotic material (Lovett Doust et al. 1994). Herons and egrets, are at the top of the food chain as predators of aquatic animals, and therefore accumulate many persistent environmental contaminants, including organochlorine pesticides, polychlorinated bipheninyles (PCBs) and metals. Their mobility and their use of agricultural habitats result in high exposure to contaminants, and their communal roosting and nesting facilitate sampling (Kushlan 1993). They are therefore good indicators of the contamination of aquatic environments (Custer et al. 1991).

Biomagnification allows the early detection, at higher trophic levels, of contaminants with relatively low concentration in the environment (Vermeer and Castilla 1991). Accumulation depends on the transfer of heavy metals in the food chain and thus on the composition of the diet at different trophic levels. Body load increases with the age of the animal, if the intake exceeds metabolic rate and excretion (Vaan Straalen 1988).

Environmental contamination by organic compounds

Several organic compounds contaminate the environment, with different properties as regards acute toxicity, persistence, and accumulation in non-target organisms. Biodegradability is the main characteristic that renders pesticides environmentally friendly.

Organocholorine insecticides:

DDT and its metabolites (DDE, DDD), with low acute toxicity but very high persistence, and very high accumulation.

Lindane, with low toxicity, and moderate persistence and accumulation

Ciclodienes (aldrin, dieldrin) with low toxicity, and high persistence and accumulation

The insectidcide DDT came into wide use in agriculture in the late 1940s. Catastrophic population declines in certain species, notably raptors, and related eggshell thinning were well documented after 1946, the period associated with the widespread use of DDT and other organochlorines. Therefore, strong concern about wildlife contamination arose in the 1950s and 1960s, in relation to persistence of DDT in the environment and to the associated mortality of some species of birds, particularly raptors and waterbirds, in Europe and in America (Beyer et al. 1996). DT was banned in the United States in 1972, and during the 1970’s in Europe, but remained in use in the developing countries of Africa and of Asia.

The manufacture and the use of organochlorine compounds in developed nations has decreased remarkably during the last three decades, but in some developing countries they are still used in the treatment of agricultural pests and as insecticides for vectors of malaria. In tropical ecosystems the environmental fate of these pollutants is affected by high temperatures and heavy rain, which increase the dispersion rate (Iwata et

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al. 1994, Kannan et al. 1995). However, few data on organochlorine pollutants in biota from tropical ecosystems have been published and, to our knowledge, no data are available from wetlands in Pakistan.

Lindane was still widely used in some parts of Asia during the 1990s.

Organochlorine-caused mortality of adult herons and egrets was attributed primarily to dieldrin exposure (Custer 2000), and the decline of many species in North America after 1945 probably resulted mainly from lowered reproductive success. Herons and egrets are highly sensitive to DDE-induced eggshell thinning, that was first documented in grey herons Ardea cinerea (Prestt 1970).

Organophosphorus (e.g. Parathion, Malathion) and carbammate (e.g. Carbaryl) insecticides, with high toxicity, but low persistence and accumulation. They are the most widely-used pesticide at present. Their low persistence diminishes the dangers for the environment.

Polychlorinated biphenyls (PCBs). These compounds have low toxicity, but are persistent. They are composed by mixtures of biphenyls at different chlonrination levels. They are very widespread, because they have several uses including insulating or cooling agents, and because contamination results from several sources including industrial discharge, leak, disposal, and incomplete incineration. Production peaked in 1970, but was then prohibited since 1979 in the United States, where their concentrations are generally low and not associated with impaired survival and reproduction of herons, with few exceptions. Declines in populations of gulls, otters and dolphins have been attributed3 to PCBs. At normal levels of exposure, PCBs are not very toxic to humans, although incidents due to food contamination occurred in Japan.

Dioxins. Appear as by-products of herbicides. Are highly toxic and teratogenic contaminants, suspected to have had adverse effects on embryonic development of bird species at some locations.

Pesticide usage is increasing, in terms of area treated, of number of applications per year, and of variety of chemicals in use. By 1990, about 300 chemicals were in use worldwide as insecticides, 290 as herbicides, and 165 as fungicides and other pesticidal compounds, with a grand total of more than 3000 formulations (Freedman 1995). Between 1945 and 1989 their use increased by 10 times in the United States, a country that accounts for about one third of the global total. For these reasons, we can expect that the impact of pesticides is likely to have increased progressively during the past 50 years, and will continue to increase in the future.

The studies about the impact of organic pesticides upon wildlife, were directed both at the effects on animals within treated areas, and at the persistence of residues away from treated areas, as summarized by Beyer et al. (1996). Among the first reports of organochlorine residues in wildlife were those of DDT in tissues of birds exposed either to laboratory or to orchard treatments in the 1950s. Experimental applications of DDT caused considerable mortality of nestling songbirds. Several filed and laboratory studies followed during the 1950s and 1970s. However, some kinds of insecticide effects were not observed until 15 years or more after the introduction of the synthetic organic insecticides. In particular, the effects in areas away from treatments were discovered after delay. These studies met several difficulties, including: standardizing the analytical methods; discerning the causal agent of mortality or of decrease among the many contaminants present in single organism; identifying the source of contaminants. Contamination studies had also to face skepticism, and sometimes opposition from people with economic interests in pesticides.

Many studies determined the amount of a chemical present in non-target organisms, and compared the value with those found to produce detrimental effects. the use of different tissues as samples for analysis made comparisons difficult. The bioaccumulation through the food chain was also investigated. Residues were not distributed equally in all habits and in all organisms. The exposure of birds and mammals to residues seemed related primarily to their food habits. Owing to pesticide-induced reproductive impairment, several bird species, especially raptors and waterbirds, become endangered or suffered strong reductions in their populations.

The presence and persistence of pesticide residues in the environment has prompted for monitoring programs, assisted by governmental agencies in Europe and America

Environmental contamination by inorganic elements

Metals and metal-containing contaminants are not degradable in the sense that carbon-based molecules are. Their nondegradability means that it is difficult to eliminate metal atoms from the environment. Therefore,

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localized, elevated levels of metal contamination may occur. These metals can accumulate in biological systems, where their toxicity poses serious threats to human and environmental health (Pepper et al. 1996).

Unlike most organic pollutants, heavy metals and other inorganic elements occur naturally , and so there is a range of normal background concentrations of these elements in the soil, sediments, waters, and living organisms. Pollution gives rise to anomalously high concentrations of these elements relative to the normal levels, therefore only their relative concentration above a certain threshold indicates pollution.

Heavy metals are widely used for several industrial productions, and consequently they tend to reach the environment from a vast array of anthropogenic sources as well as natural geochemical processes. Anthropogenic sources include:

metalliferous mining and metallurgical industries

agricultural fertilizers (that may include impurities with Cd, Cr, Mo, Pb, U, V, Zn)

agricultural pesticides (with Cu, As, Hg, Pb, Mn, Zn)

agricultural desiccants (As for cotton)

wastes and sewage from animal farms (As, Cd, Cr, Cu, Ni, Pb, Zn)

fossil fuel combustion (As, Ba, Cd, Cu, Ni, Pb, Sb, Se, Mn, V)

other sources, manufacture and disposal

Monitoring heavy metal concentration in biota can reveal trends in time and space of the body burden of organisms (Reid and Hacher 1982). It is also used to explore the nature and extent of the biological impact of these metals (Ernst 1991). Heavy metal concentration can be compared to background levels, and their bioavaibility can be determined. Biomonitoring heavy metals can help when supervising and adjusting government action to correct this pollution (Canters and Snoo 1993).

After absorption, heavy metals accumulate particularly in bone, kidney, liver, and in feathers. Bird feathers are particularly useful as an indicator tissue for metal exposure, and have been intensively used to this aim since the 1960 (Burger 1993). Feathers are rich in keratin, and the metals and metalloids bind to their sulfhydryl groups. Metal concentration in feather reflects the levels present in the body of the bird at the time of feather growth, when their blood supply is intact (Goede and deBruin 1984). Circulating levels, however, can come from current ingestion (through food or water) or from mobilization from metal stored in other tissues. Indeed, one mechanism birds have for the elimination of heavy metals from their bodies is to sequester them in their feathers (Braune and Gaskin 1987, Becker et al. 1993). Metals can also be eliminated directly throught excreta, throught the salt gland (Burger and Gochfeld 1985) or can be stored in tissues (Braune and Gaskin 1987, Burger 1994). For Mercury, 93% of the body burden is in the birds’ plumage (Braune and Gaskin 1987). Moreover, nestling of birds such as herons and egrets lose the down they are born with, and grow entirely new plumage while being cared for by their parents. Thus, metal levels in their feathers come from the local environment, and can be used as a good indicator of local pollution. Further, collecting feathers is non-invasive, and birds can be released alive; feathers are easily collected, handled, and stored in the field and don’t require refrigeration and the same birds can be sampled repeatedly. Furness et al. () suggest that body feathers are the more suitable tissue for analysis than other feathers, such as those from wings and tail.

Females can also sequester heavy metal in their eggs (Burger and Gochfeld 1993, Dauwe et al. 1999), and high levels of mercury (Fimreite et al. 1982, Haseltine et al. 1981), of lead, cadmium (Maedgen et al. 1982), and of other metals (Burger and Gochfeld 1991, 1993, 1995), have been reported for eggs. In general, mercury accumulates well in both feathers and eggs, while cadmium and lead accumulate better in feathers than in eggs. So eggs can supplement feathers, providing additional information than either alone (Becker et al. 1993).

Hazardous heavy metals. The most hazardouse elements of concern to waterbirds include cadmium, chromium, mercury, lead, and selenium. (Kushlan & Hafner 2000). At high dose, heavy metals produce lethally toxic. At low doses, they can cause sublethal toxic effects, such as slower reactions to stimuli or weight loss (Honda et al.1990) Toxic effects of heavy metals are also related to their bioavailability (Graveland 1990), and to the organism’s physiological status (Osborn 1979, Blomqvist et al. 1987, Krasowski and Doelma 1990). The interactions between metals are very important as well. Lead, for

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example, interacts with calcium or phosporus (Graveland 1990) and interactions between cadmium and copper, zinc or selenium are well known (Voogt et al. 1980, Goede and Voogt 1985).

Cadmium. A highly toxic non-essential metal, that is a known teratogen and carcinogen, and is probable mutagen. In birds, effects of chronic cadmium exposure typically include growth retardation, anemia, and testicular damage (Eisler 1988). It may induce intracellular production of metallothionein, a low- molecular-weight protein rich in sulfur aminoacids to which cadmium can be bound and, hence, rendered less toxic. A high accumulation of cadmium can, but does not always, lead to food chain amplification, because metallothionein-bound cadmium has a long biological half life in animals and because concentrations tend to increase with age. Cadmium concentrations in birds are almost always highest in the kidney, lower in the liver and very low in muscle and in eggs. It’ s often not clear wether cadmium in feathers is derived from deposition into growing feathers from circulating cadmium in the blood, or wether it is all from atmospheric or aqueous deposition onto feather surfaces (Hahn 1991), so feathers provide little or non information on cadmium accumulation from food.

Chromium. A micronutrient that is essential to animals. Toxic concentrations for fish range from 0.2 to 5 ppm of water.

Mercury. A toxic metal with no known essential function in vertebrate organisms. Mercury is neurotoxic and teratogenic, and it is resposible for poisoning of human population through the food chain, from waste to sediments, to fish consumed by hemansFish-eating birds such as herons and egrets are exposed to mercury (particularly methylmercury, that is the most stable and toxic form of mercury) in the diet. Much ingested mercury goes into plumage during feather growth, and the body pool of mercury declines as moult progresses. In growing chicks, mercury concentrations increase in down but not in soft tissues with age. Feathers from nestlings provide a good indicator of mercury exposure of the adults.

Lead. A nonessential metal, highly toxic heavy metal that affects all body system. The main sources of lead pollution are petrol, fumes from petrol combustion, constituents of paint and solders, lead shots used for hunting. ON a comparative basis, lead is neither as toxic as many other heavy metals nor as bioavailable; however, it is more obiquitous and it is a cumulative toxic. Lead absorption may result in a range of sublethal effects or in mortality. It acts at the molecular level affecting the haematological, muscular, behavioral, nervous and reproductive system. Aquatic birds at risk from lead include waterbirds like ducks and geese, inhabiting areas with frequent hunting activities. These birds ingest lead shots from the bottom surface, as they ingest small stones in order to facilitate digestion. Avian predators may eat gamebirds wounded by hunters, and aquatic birds feeding near smelters, refineries and lead battery recycling plants may be contaminated. Herons and egrets are generally not at risk from lead, because they do not normally ingest lead shot, and because forms of lead other than shot do not generally cause clinical signs of lead poisoning in birds. Lead, like cadmium, cannot be entirely removed by washing procedures, and lead concentrations in feathers can be attributable both to external contamination and to dietary lead uptake during feather formation. This could happen particularly in areas subject to the heavy vehicle traffic and continued use of leaded gasoline.

“Essential” elements. Some elements are required by living organisms in small but critical concentrations for normal health, and are therefore referred to as “essential”, because they are constituents of enzymes and of other important proteins, but their excess concentrations cause toxicity. Elements that are certainly essential are Cu, Mn, Fe, and Zn for both plants and animals, cobalt, Cr, selenium and I for animals, B and Mo for plants. Some other elements have been shown to have some beneficial effect, but are not likely to be responsible for deficiency under normal conditions. Their absorption is regulated by homeostatic mechanisms (Friberg et al. 1986).

Copper may cause toxicity problems in animals grazing on polluted soils if the herbage contains >10 ppm of Copper.

Very little information is available on the effects of manganese, iron, and cobalt.

Selenium is a naturally-occuring trace element that is essential for animal nutrition, but the range between dietary requirements and toxic levels is relatively narrow (Eisler 1985, Ohlendorf 1989).

Zinc is an essential nutrient for higher animals, and toxicity values are generally greater than values for non-essential metals. It is relatively non-toxic to animals, and several zinc-based enzymes or other proteins have been identified.

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“Non-essential elements”. Other elements with no known essential biochemical function are called “non-essential elements” and cause toxicity at concentrations exceeding the organism’s tolerance. All these elements may be responsible for toxicity at high doses.

Arsenic. Arsenic has been rarely determined in aquatic animals. It is a toxic, non-essential element. The concentrations found in wildlife range from non-detectable to 2.9 ppm ww. Therefore, the values we found in tadpoles are rather high.

Very little information is available on the effects of silver, Bromine, cesium, lanthanum, nickel, scandium.

The behaviour of pollutants in the soil

Sediments are repositories for physical and biological debris and sinks for a wide variety of chemicals. The concern associated with the chemicals sorbed to sediments is that many commercial species and food-chain organisms spend a major portion of their life-cycle living in or on aquatic sediments. This provides a pathway for these chemicals to be consumed by higher aquatic life and wildlife, including avian species as well as humans. Direct transfer of chemicals from sediments to organisms is now considered to be a major route of exposure for many species. These issues are focusing attention on sediment contamination and highlight the fact that sediments are an important resource (Adams et al. 1992).

Because sediments are both carriers and potential sources of contaminants in aquatic systems, these materials may also affect groundwater quality and agricultural products when disposed on land. Contaminant are not necessarily fixed permanently in the sediments but may be remobilized when physico-chemical conditions change. Bioavailability of toxic chemicals and food-chain transfer may be strongly affected by such processes and by the type of chemical binding on the sediment particles. When pollutants reach the soil surface they are either adsorbed with varying strengths on the colloids at the surface of the topsoil, or are washed down through the surface layer into the soil profile in rainwater or snow melt. Soluble pollutants will infiltrate into the topsoil in the system of pores where the adsorption of ions occurs. Insoluble compounds will accumulate on the surface and hydrophobic organic molecules will bind to sites on soil organic matter at the soil surface. These substances become incorporated into the topsoil and deeper profile during mechanical soil movement or down dessiccation cracks while being adsorbed on soil particles. Some organic pollutant molecules on the soil surface will undergo photolytic decomposition as a result of exposure to UV wavelengths in daylight.

Several different types of adsorption reaction can occur between the surfaces of organic and mineral colloids and the pollutants. The extent to which the reactions occur is determined by the composition of the soil (especially the amounts and types of clay minerals, hydrous oxides and organic matter), the soil pH, redox status, and the nature of the contaminants. The more strongly pollutants are adsorbed, the less likely they are to be leached down the soil profile or to be available for uptake by plants. Ionic pollutants such as metal, inorganic anions and certain organic molecules, such as the bipyridyl herbicides (e.g Paraquat), are adsorbed onto soil colloids. Non ionic organic molecules, which include hydrocarbons, most organic micropollutants and pesticides, are adsorbed onto humic polymers by both chemical and physical adsorption mechanisms. However, some organic pollutants, such as solvent, tend to be relatively easily leached in regions where there is a marked excess of precipitation relative to evapotranspiration. In many cases, adsorption is a necessary preliminary stage in the decomposition of organic pollutant molecules by bacterial extracellular enzymes.

Heavy metal ions in soils: heavy metal pollution can affect all environments but its effects are most long lasting in soils because of the relatively strong adsorption of many metals onto the humic and clay colloids in soils. The duration of contamination may be for hundreds or thousands of years in many cases (e.g. half-lives: Cd, 15-1100 years; Cu 310-1500 years and Pb 740-5900) years depending on the soil type and their physicochemical parameters). Unlike organic pollutants, which will ultimately be decomposed, metals will remain as metal atoms, although their speciation may change with time as the organic molecules binding them decompose or soil conditions change.

The extent to which metal ions are adsorbed by cation exchange ( non specific adsorption) depends on the properties of the metal concerned (valency, radius, degree of hydration and coordination with oxygen), pH, redox conditions, the nature of the adsorbent (permanent and pH-dependent charge, complex-forming ligands), the concentrations and properties of other metals present, and the presence of soluble ligands in the surrounding fluids. The selectivity of clay mineral and hydrous oxide adsorbents in soils and sediments for divalent metals generally follows the order Pb > Cu > Zn > Ni > Cd, but some differences occurs between

8

minerals and with varying p H conditions. The selectivity order for peat has been shown to be Pb > Cu > Cd = Zn > Ca. However, in general, Pb and Cu tend to be adsorbed most strongly and Zn and Cd are usually held more weakly, wich implies that these latter metals are likely to be more labile and bioavailable.

In general, nearly all metals (Except Mo) are most soluble and bioavailable at low pHs and, therefore, toxicity problems are likely to be more severe in acid environments. In the case of pollution by particles of sulphide ore minerals, the weathering of the sulphide exacerbates the problem by increasing the acidity of the soil. In agricultural soils this situation can be mitigated to a considerable extent by liming.

Sediment quality assessment

Sediment quality assessment is considerably complex due to the many site-specific parameters as bioavailability, sorption kinetics, sediment characteristics (buffer capacity and acid-producing capacity), sediment deposition and erosion (redox potential) and temporal and spatial differences. The methodologies developed to date do not adequately deal with the complex nature of sediments.

The way in which sediments are sampled and stored for bioassays or spiked for toxicity tests can lead to unacceptable variability in results. It is probable that some of the variability in toxicity tests could be eliminated by the use of artificial sediments, although useful tests can be conducted with natural sediments providing that the range of acceptability for certain parameters such as the particle size spectrum and the organic carbon content is tightly defined. There is also need to develop statistical methods that can be used for analysing dose-response relationships in sediment bioassays which usually include the complex mixture of substances present in contaminated sediments. Tab. 1.1 gives an overview of the various chemical available to assess sediment quality.

With regard to chemical methods, there is no immediate indication on biological effects. Their major advantages lie in their easy application and amendment to modelling approaches. The Background approach compares actual data with sites comprising natural or insignificant pollutant concentration. The total metal concentrations in sediments are not good estimations of the bioavailable fraction. The dominant role of the sediment sulphides in controlling metal bioavailability has been demonstrated (Ankley et al. 1991; Carlson, 1991; Di Toro et al. 1992); they are the key factor for controlling the toxicity of cadmium and nickel and potentially several other heavy metals (Di Toro et al. 1992). No toxicity is observed from these metals when bounds to sediments and when, on a molar basis, the concentration of AVS is greater than the sum of the molar concentrations of the sulphide-binding metal. When the ratio of the AVS to metal concentration drops below 1, toxicity begins to appear.

With regard to prediction of long-term effects of sediment-bound metals, chemical extraction procedures are of limited value because they usually involve neither reaction-mechanistic nor kinetic considerations. This lack, can be avoided by an experimental approach, where sediments can be treated in a circulation system under controlled intensification of significant release parameters such as pH, redox-potential and temperature. This method (Schoer and Forstner, 1987) includes an ion-exchange system for extracting and analysing the released metals at an adequate frequency, and compares sequential extraction before and after treatment of the samples in the circulation apparatus.

The equilibrium partitioning approach has been chosen because it addresses the two principal technical issues that must be resolved: the varying bioavailability of chemicals in sediments and the choice of the appropriate biological-effect concentrations. This approach is based on the theory that contaminants sorbed to sediments achieve thermodynamic equilibrium over appropriate periods of time between sediment and sediment and sediment pore water concentrations. At equilibrium, the mass of the chemical present in either phase can be estimates by measuring the mass present in the other phase.

The apparent effects threshold method (AET) uses empirical field and laboratory data to identify concentrations of chemicals above which biological effects are always expected. A wide variety of organisms and biological tests can be used to obtain effects data. These may include benthic infaunal field surveys and bulk sediment bioassays with various organisms and endpoint.

The composition of interstitial water is the most sensitive indicator of the types and extent of reactions that take place between contaminants on the sediment particles and the aqueous phase which contacts them. The interstitial water approach is a procedure for measuring the toxicity of sediment-bound chemicals to aquatic organisms by exposing the organisms to pore water extracted from sediments. Pore water toxicity tests can

9

be performed with a variety of test organisms, both benthic and water column species. This method is based on the assumption that the pore water is in equilibrium with the surrounding sediment and that the water phase provides a directc and important route of exposure for organisms that live in sediments.. I t also assumes that the “soluble” or “free” uncomplexed fraction of any chemical in the pore water is the fraction most responsible for observed sediment toxicity (Di Toro et al. 1991).

In the spiked sediment toxicity approach, the toxicity of a specific chemical to one or more benthic organisms is measured by the addition of the chemical to the test sediments in different doses.

The tissue residue approach relies on an ability to establish a maximum concentration of a chemical in sediment that will result in an acceptable concentration in aquatic organisms or consumers of aquatic biota like humans, birds or mammals.

Finally, the sediment quality triad method involves a combination of biological laboratory and field data in comparison with chemical analyses which compensates the limitations of the individual methods. It consists of three components (Chapman, 1986):

Identification and quantification of inorganic and organic contaminants in the sediment with the lowest limits of detection possible

Measurement and quantification of toxicity based on bulk sediment laboratory toxicity tests.

Evaluation of in situ biological effects or alteration._______________________________________________________________________________________

Tab. 1.1. Methods for assessing sediment quality (from Calmano W et al. 1996)_______________________________________________________________________________________Chemical methods Integrated Chemical and biological method Biological method

Back ground approach Equilibrium partitioning Bulk sediment toxicityAcid volatile sulfide (AVS) Apparent effects threshold Fresh benthic approachSubstrate composition Interstitial water toxicityLong term mobility Spiked sediment toxicity

Tissue residue approachSediment quality triad

_______________________________________________________________________________________

The most useful sediment toxicity tests and bioassays are those which measure the chronic toxicity resulting from long-term exposure because some sedimentary contaminants can be persistent. However, partly due to problems associated with feeding sediment dwellers in a natural way and partly due to our lack of understanding the optimum living conditions for these organisms, there are very few sediments tests which are currently able to measure chronic effects.

As with all ecotoxicological data the most difficult problem in sediment toxicity assessment is the reliable comparison of data obtained under different sediment conditions and the confident extrapolation of laboratory-derived sediment test results to the field situation. Some progress has been made for neutral organic compounds by normalising for the organic carbon content of the test sediment. Normalising for acid volatile sulphide (AVS) may have equivalent utility for certain metals. However there is a need to develop similar normalising procedures for the many other confounding factors in sediment test to enable all test results to be reliably compared. Extrapolation to field situations is even more difficult at present because we have little information about the impact of sedimentary contaminants under natural conditions. Until we have a much larger data base of information on pollution effects in experimental mesocosm sediments and are able to relate bioassay responses in a more structured way to known impacts on wild communities of benthic organisms, we will not be able to derive specific applications or safety factors to be used when extrapolating sediment toxicity results.

Pollutants in contaminated soil

Many states or countries have established lists of critical concentrations (or trigger concentrations) for the risk assessment of site and environmental survey data. The basis for these different sets of values varies

10

according to the target groups they are intended to protect from the effect of the pollutants. Examples of critical concentrations of heavy metals used in different countries are given in Tab. 1.2, 1.3, 1.4.

Tab. 1.2 shows the critical concentrations used in the Netherlands for contaminated soils. The system is based on ecological function and comprise target values (TV) for soils which represent the final environmental quality goals for the Netherlands. The critical values for soils given Table 1.3 for the UK by the Department of the Environment Interdepartmental Committee for the Reclamation of Contaminated Land (ICRCL). The list of Trigger Concentrations for Contaminants (DOE, 1987) are more pragmatic and based mainly on the risk to human health. Unlike the Dutch standards, the ICRCL values vary for different proposed uses of the contaminated land. The lowest values are given for garden soils where vegetables are likely to be grown, with higher values for parks and open spaces, and the highest values for land to be developed for industrial uses where the transfer o pollutants from the soil to plants is not likely to be significant in terms of his impact on human health.

The new Canadian National Classification System from contaminated soils shown in table III is intended for use in the evaluation of contaminated sites. The values in the tables enable sites to be classified as high, medium or low risk according to their impact (current or potential) on human health and ecosystems. It is a screening system and not intended to be a quantitative risk assessment for individual sites. The 1991 Environmental Quality standards for Netherlands give target values for soils which will be very difficult and expensive to achieve, especially in the case of some of the ubiquitous contaminants such as Pb. The Threshold value for Pb under the ICRCL scheme used in the UK is 500 mg/g. This implies that concentrations below this figure should not cause problems. In contrast, the Dutch target value for Pb is 85 mg/g (for a standard soil) and the Canadian background value is even lower at 25 g/g, but the trigger concentration for remediation of agricultural land is 375 g/g. The Dutch scheme is based on the ecological effects of contaminants and, therefore, soils meeting the target values would be suitable for any use, such as food production or nature conservation. However, the UK and Canadian values take into account different uses of land. The UK value of 500 g/g Pb is the most achievable, because many urban soils in the UK would come within this range and the more excessively polluted sites would be considered unacceptable.

Of particular relevance is the intended future use of the contaminated land. In some countries, such as Netherlands, the intention is to ameliorate the site to a specification which allow the land to be used for any purpose (multifunctionality). The more pragmatic approach in other countries, such as the UK, is to relate the site quality specification to the intended use. For example, a contaminated site required for development as a warehouse complex would not need to have such low concentrations of toxic compounds as a site to be used for housing, where the residents may grow vegetables in their gardens. However, any explosive hazard, such as methane release, would need to be removed for both new uses o the site. Even though the use of a site may not require a high degree of clean-up, the remaining contaminants may migrate within the soil to the ground-water, undergo chemical changes or remain a potential problem fo future uses of the site.

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________________________________________________________________________________

Tab. 1.2. Guide values and quality standards used in Netherlands for assessing soil contamination by heavy metals (Netherlands Ministry of Housing, Phisical Planning and Environment, 1991). STV values in g/g.

________________________________________________________________________________Arsenium 29Bario 200Cadmium 0.8Cobalto 10Chromium 100Copper 36Mercury 0.3Molibdeno 10Nickel 35Lead 85Sn 20Zinc 140________________________________________________________________________________

______________________________________________________________________________________

Table 1.3. UK Department of the Environment ICRCL trigger concentrations for environmental metal contaminants (total concentratione except where indicated) (Department of the Environment, 1987).

______________________________________________________________________________________Contaminant (g/g) Proposed uses Threshold trigger concentration

Contaminants which may pose hazards to homan health

Arsenium Gardes, allotments 10Parks, playng fields, open space 40

Cadmium Gardes, allotments 3Parks, playng fields, open space 15

Chromium (hexavalent) Gardes, allotments 25Parks, playng fields, open space -

Chromium Gardes, allotments 600Parks, playng fields, open space 1000

Lead Gardes, allotments 500Parks, playng fields, open space 2000

Mercury Gardes, allotments 1Parks, playng fields, open space 20

Selenium Gardes, allotments 3Parks, playng fields, open space 6

Phytotoxic contaminants not normally hazardous to health

B (water soluble) Any uses where plants grown 3

Copper (total) Any uses where plants grown 130(extractable) 50

Nickel (total) Any uses where plants grown 70(extractable) 20

Zinc (total) Any uses where plants grown 300(extractable) 130

______________________________________________________________________________________

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______________________________________________________________________________________

Table 1.4. Selected values from the Canadian interim environmental quality criteria for soil (Canadian Council of Minister of the environment, 1993), soil concentrations in g/g.

______________________________________________________________________________________Background Agricultural Residential Industrial

Arsenium 5 20 30 50Bario 200 750 500 2000Berillium 4 4 4 8Cadmium 0.5 3 5 20Cobalto 2.5 8 8 -Chromium 10 40 50 300Copper 30 150 100 500CN 0.25 0.5 10 100CN 2.5 5 50 500Lead 25 375 500 1000Mercury 0.1 0.8 2 10Molibdeno 2 5 10 40Nickel 20 150 100 500Se 1 2 3 10Silver 2 20 20 40Sn 5 5 50 300Zinc 60 600 500 1500

______________________________________________________________________________________

Aims of this research

As coastal and inland wetlands in Pakistan and China are subject to increasing pollution from industrial, urban and agricultural sources, there is a growing urgency to monitor contaminant levels, to assess the effects of pollutants, and to evaluate the resilience of these wetlands to pollution. The approach of our study focused on the use of colonial waterbirds as bioindicators of environmental contamination and other ecosystem changes.

The general objectives of this study were to assess pollutant levels and effects in selected coastal and inland wetlands in Pakistan and China, using egrets and herons (colonial waterbirds of the Order Ciconiiformes, Family Ardeidae) as bioindicators. We considered the most widespread contaminants with long term persistence:

inorganic elements, particularly heavy metals and other elements of environmental concern (Cd, Cr, Hg, Pb, Cu, Fe, Mn, As, Ag, Br, Co, Ce, La, Ni, Sc, Se, Zn

DDT and derivates

other organochlorines (HCH+HCB, -HCH, -HCH, -HCH, heptachlor-epoxide -endosulfan).

Polychlorinated biphenyls (PCBs)

Because of the heightened interest in wetland conservation throughout the world, herons and egrets have become a valuable and popular monitoring guide, because of their conservation value, their vulnerability and their conspicuousness. (Erwin and Custer, 2000). Moreover, their use for monitoring purposes can provide data on both exposure hazards and effect responses. A number of aspects of the biology and behaviour of egrets and herons, makes them particularly appropriate as bioindicators: they are top predators and thus liable to concentrate contaminants, are widespread, use a variety of habitats, and have been intensely studied so that abundant comparative information is available (Kushlan 1993, Erwin & Custer 2000). The species selected for study was the Little Egret Egretta garzetta, one of the most widespread and common of the Ardeidae.

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Biological properties at various hierarchical levels have been used as indicators of environmental quality, and of contamination in particular. Since biomonitoring programs are most effective when they use a combination of indicators, at different levels of organization, our research program included the study of:

eggs: contamination by organic compounds, as indicator of general environmental contamination

feathers: contamination by trace elements, as indicator of general environmental contamination

suborganismic characteristics (eggshell thickness, haemathological variables), as indicators of contaminants effect on physiological conditions

breeding success (clutch size, hatching and fledging success, ,growth rate of chicks), as indicator of the present impact of contaminants

breeding population size, as indicator of the long-term impact of contaminants

prey of the egrets: contamination by organic compounds and by trace elements, as indicator of the present contamination of particular habitats

sediments collected in the feeding habitats of the egrets: contamination by organic compounds and by trace elements, as indicator of the long-term contamination of particular habitats

For each country, Pakistan and China, we selected one wetland exposed to industrial-urban pollution, one to agricultural pollution, and one thought to be relatively unpolluted; all selected wetlands are of recognised national and/or global importance. The results may indicate the level of pollution in the populations and ecosystems studied, highlight any potential threats to human health, and provide valuable baseline data for comparison with future conditions in these populations and ecosystems and elsewhere in Asia. The outputs will be useful for management of these important wetlands, for national policy formulation for pollution control and wetland conservation, and for the strengthening of pollution control regulations.

We aimed to assess both residue levels and effects of pollutants. We expected residue levels to differ among study areas in relation to ecosystem-level pollution, and particular sources of pollution to be indicated by the types of contaminants and by their patterns of concentrations in the different samples.

Specific objectives were:

to measure residue levels of organochlorine compounds and PCBs, and of selected heavy metals and other elements, in feathers and eggs of Little Egret;

to measure selected population variables (size of breeding population, success of sample nests) of these Little Egret populations, and record aspects of their behavioral ecology (foraging habitat, foraging success of sample adults) that may be related to contamination;

to infer exposure of these Little Egret populations to pollutants and the general bioavailability of pollutants, and to infer exposure to other ecosystem changes;

to assess qualitatively and quantitatively ecosystem-level contamination and other ecosystem changes as indicated by residue levels and by population and behavioural variables in Little Egrets

to identify whether concentrations of contaminants found, and any other ecosystem changes observed, are at levels associated with adverse effects on reproduction;

to further test the usefulness of colonial waterbirds as bioindicators of environmental contamination and ecosystem change; and

to disseminate the results among environmental toxicologists and other scientists, ecosystem managers, environmental policy formulators and legislators.

We summarize here the results of the ecological studies, sample collection and chemical analysis. The ecological data, besides their own biological interest, provide a background information for the interpretation of the contamination levels.

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2.

Study areas

Fasola MauroDipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

The following 6 wetlands were selected for study on the basis of the presence of breeding colonies of egrets and herons, of their national and global importance, and of their various exposure to contamination (Fig. 2.1, 2.2, 2.3).

1) Poyang Lake, Jiangxi, China (115°49'-116°46'E, 28°24'-29°46'N): a freshwater lake, the largest in China (328,300 ha) and the most important site for waterfowl in China, established as a NEPA nature reserve, expected to be free of pollution. Poyang Lake is the largest freshwater lake in China. It is located in the floodplain of five inflowing rivers, and it also receives backflow from the Yangtze River at high floods. It is still in a near-natural state, and the difference between low water levels in winter and high water levels at the height of the summer flood might be of 11 metres. Since time immemorial, the whole area of the lake (170 kilometres long by 17 kilometres wide), and its floodplain has been used by humans for fishing, for grazing of buffaloes and for cutting of vegetation as fuel. Moreover, the lake constitutes a very important wintering area for waterfowl. For instance, up to 98% of the Siberian Crane (Grus leucogeranus), a species of great interest from the point of view of conservation, winters at the Poyanghu. Large colonies exist with breeding Little Egrets, Intermediate Egrets, Great White Egrets, Cattle Egrets, Chinese Pond Herons, and Night Herons.

2) Tai Lake, Jiangsu Province, China (30°19’ to 32° 00’ N, 119° 21’ to 122° 00’ E). One of the largest freshwater lakes in China (242,500 ha), situated in a highly productive rice-growing area, expected to be subject to serious pesticide and heavy metal pollution from both agriculture and industry. Tai Lake, with an area exceeding 1,200 km P

2P, is located near Wuxi, an industrial city with a population of 1

million. The agriculture in this area is highly productive and it is mainly devoted (90% of farmed land) to rice fields. Tai Lake has at its northern part Lake Wulihu, a lagoon of approximately 10 km P

2P.

Several tributaries connect the two lakes with other bodies of water such as the Yangtze River. Lake Wulihu receives millions of tons of industrial waste water and domestic sewage from Wuxi. Tai Lake also receives direct inputs of agricultural and some industrial pollutants, as well as sewage from small towns on the west side of the lake. During most of the year, water flows from Tai Lake to lake Wulihu, but reverse flow in winter/spring, brings water from lake Wulihu to the Taihu (Zou et al. 1996, Dong and Zhang, unpubl.). Very large colonies of Night Herons, Little Egrets, Chinese Pond Herons, and Cattle Egrets, are scattered throughout this area.

3) Pearl River Delta and Coastal Area, Guangdong, China (112°15'-114°15'E, 21°31'-23°15'N). A wide area, of about 38,000 ha, expected to be subject to urban-industrial pollution. The study site was the “Ecological Paradise”, a recreational area, located close to the municipality of Shunde. Guangdong Province is one of the important production areas for traditional rice-fish culture and freshwater fish farming in China. In 1998, its freshwater farming area reached 362,128 ha, and the output was 1,903 million tons, of which 235,936 ha were ponds with a total output of 1,744 million tons; 93,726 ha were reservoirs with a total output of 774,000 tons; 29,662 ha were paddy fields with a total output of 202,000 tons. There are three major types of freshwater culture: 1) traditional freshwater farming of four major Chinese carps: Grass carp, Carp, Silver carp, Bighead; 2) introduction of foreign breeds: Large mouth bass, Tilapia, Pacu, Macrobrachium rosenbergii, Silvery Pomfret; 3) Culture of local

15

wild species: Eel, Mandarin fish, soft-shelled turtle, China soft-shelled turtle. Large colonies with several species of herons and egrets are scattered throughout this area.

4) Haleji Lake, Sindh Province, Pakistan (25°48’N, 67°47’E). A freshwater lake, surface area 1,704 ha, with associated marshes and adjacent brackish seepage lagoons, expected to be relatively unpolluted. The site is located 15 km west-nortwest of Thatta, and 75 km west of Karachi. Haleji Lake is a ‘clean’ freshwater reservoir with associated marshes and adjacent seepage lagoons, located amid a stony desert, and covering an area of 10.53 km P

2P, reaching a maximum depth of 6 m. Since there is no

agriculture nor industrial activity in the surroundings, pollutants may reach the reservoir mainly through atmospheric deposition. This wetland hosts regularly between 50,000 and 100,000 birds and it is especially important for breeding Ardeidae. The most abundant breeding herons and egrets are the Night Heron and the Intermediate Egret, with lower numbers of Indian Pond Herons, Little Egrets, and Purple Herons.

5) Taunsa Barrage, Punjab Province, Pakistan (30°42’N, 70°50’E). A storage reservoir behind a barrage on the River Indus, expected to be subject to pollution from agriculture. Taunsa Barrage is located 20 km northwest of Kot Adu, Muzaffargarh District. It is a large water storage reservoir situated behind a barrage on the Indus River. Agriculture, mainly cotton, sugar cane, wheat and fodder crops, livestock grazing and forestry occur in adjacent areas, but also the barrage is used for power generation, therefore some impact of PCBs is to be expected the land that is exposed to low water levels is leased to local farmers for cultivation during the dry season. A few large colonies with several species of egrets and herons exist in this area.

6) Karachi Harbour, Pakistan (24°47’N, 67°11’E; 112). Tidal creeks, mangrove swamps and intertidal mudflats, expected to be subject to considerable urban and industrial pollution. The study site was Karachi Ghas Bunder, located in the city of Karachi. It is a degraded mangrove area within the Karachi Harbour, and it is exposed to high industrial pollution. About 45% of Pakistan Industries are located in Karachi area, and all their effluents plus the domestic sewage from the city (more than 8 million people) find their way, untreated, into the sea (Khan unpublished). Furthermore, Karachi Harbour is also exposed to ship wastes and oil spills from the port’s oil terminal. Therefore, a high incidence of PCBs is to be expected in this area. Only one colony of Little Egrets (dark morph) was found in this area and n the surrounding coastal areas.

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Fig. 2.1. Location of the 6 study areas in China and in Pakistan

Fig. 2.2. Location of the 3 study areas in Pakistan. 1: Haleji Lake, 2: Taunsa, 3: Karachi.

17

Pearl River Delta(industrial. pollution)

Taunsa barrage(agricultural pollution)

Tai Hu(agricultural pollution)

Haleji Lake(unpolluted)

Poyang Lake(unpolluted)

Karachi Harbour(industrial pollution)

Fig. 2.3 . Location of the Tai Lake and of the Poyang Lake study areas in China.

Fig. 2.4. Location of the Pearl River Delta study area in China.

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3.

Methods for sample collection and for the ecological studies

Fasola MauroDipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

General approach

Our initial program included only one species, the Little Egret, as monitor of contamination. For the ecological data however, we decided to consider all the other herons and egrets breeding in the same colonies, or foraging in the same wetlands, because this could be done with very little additional effort, but on the other hand it would greatly increase the completeness of the study.

The collection and analysis of contamination samples remained restricted to the Little Egret, owing to the high cost of the chemical analyses. In some cases however, Little Egrets were too scarce to provide sufficient samples, and we were forced to shift to the most similar species (the Intermediate Egret, or theCattle Egret) as sample species.

The following species of herons, egrets, and other waterbirds, were studied:

Little Egret Egretta garzetta. Wery widespread, both in China and in Pakistan, in all kinds of wet habitatsl, both natural wetlands and flooded cultivations. It was the main study species for this project, and egg, feathers, and prey samples were collected from Little Egrets wherever they were sufficiently abundant A dark morph of the Little Egret, present in the Karachi study area, is sometimes identified as a separate species, the Western Reef Heron Egretta gularis., This is a polymorphic group that include dark, white, and intermediate egrets birds almost identical to the Little Egret. Presently, most authors (Hancock & Kushlan 1984, Kushlan & Hafner 2000) consider all these egrets as conspecific. Egretta garzetta schistacea is thus considered a subspecies, and simply a dark colour morph, of the polymorphic species Little Egret, and it will be.thereafter referred to in this report as “ Little Egret, dark morph ”. The Western Reef heron occurs only along the coastline from the Arabian Peninsula and spend most of their time foraging in salt water or the tidal zone, while the Little Egret is almost entirely a freshwater feeding species. Samples from Little Egret, dark morph, were collected in the Karachi study area, where it was he only abundant species.

Intermediate Egret Egretta intermedia. Intermediate Egrets occur in Southern China and in Pakistan. It was the most abundant egret at Haleji Lake, and because of the ease with which its nests can be sampled, it was the main study species in this area.

Great White Egret Egretta alba. Widespread both in China and in Pakistan, in all kind of wetlands.It was not abundant in any of the study areas, and few data were collected on its ecology.

Cattle Egret Bubulcus ibis. This species spread in Pakistan with the development of irrigation. It is a largely sedentary species, well adapted to grassland areas and to cultivated areas. This species is much more insectivorous than the other egrets, and is the only egret foraging usually on dry land. This species was sampled exclusively at Taunsa, where Little Egrets were very scarce.

Night Heron Nycticorax nycticorax. Widespread throughout Southern Asia. Some samples were collected at Tai Lake from Night Herons, in order to provide comparative material for another research on contamination, that was by the Institute of Soil Science, Chinese Academy of Sciences, with additional funds provided by the Chinese government.

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Chinese Pond Heron Ardeola bacchus. Present in small numbers in the study areas of China. Few data were collected on its ecology.

Indian Pond Heron Ardeola grayii. Present in small numbers in the study areas of Pakistan. Few data were collected on its ecology.

Gray Heron Ardea cinerea. Observed in the study areas of both China and Pakistan, and few data collected on its ecology.

Purple Heron Ardea purpurea. Observed in the study areas of both China and Pakistan; few data collected on its ecology.

Javanese Cormorant Phalacrocorax niger. This species has been in the past considered conspecific with P. pygmaeus , although both are easily separable in breeding plumage. In Pakistan this cormorant prefers freshwater areas. On Haleji Lake, the colonies occupied the small rocky islands inside the lake, nesting on reed-beds. Diet consist predominantly of small fresh water fish species, as well as frogs and tadpoles. Some samples were collected from this species as well at the Haleji study area, where the target species, the Little Egret, was scarce.

During May and June 1999, teams of Asian plus European researchers worked jointly in the Haleji and in the Poyang study areas. This joint work was also intended as training, so as to ensure that all the researchers adopt exactly the same techniques. During May and June 2000, joint Asian-European teams worked in the remaining 4 study areas. In each study area, colony census ,was completed, breeding success, foraging habitat and feeding success were recorded, and samples for chemical analysis were collected.

Ecological records

We standardized as much as possible the collection of ecological records, so that the data for the different study areas could be compared. Methods in the field were described in detail in a 20-pages booklet “ Workplan and methods for Ecological Fieldwork & Sample Collection” that included standardized data forms, and that was distributed to each participant before each field season. These methods follow the ones already tested in previous studies (Fasola 1994, Fasola 1998). But the specifics detailed below were fulfilled completely only in a few cases, because of local constraints.

Colony census

The goal was to identify and to census all the waterbird colonies within a general study area of few hundred square kilometers. The recommended census technique was:1. locate all the colonies within the study area (an area of 100-200 km P

2P)

2. visit each colony repeatedly during the egg and the chick stages 3. for the most abundant species with indistinguishable nests (i.e. most medium-size species of herons and

egrets), perform a “sample count”, i.e. evaluate the numeric proportion between the species during 3 or 4 visits, spaced through the breeding period. This proportion must be assessed by counting and by identifying nests (distinguished on the basis of the breeding adult or of the chicks) and not by counting the flying adults. In large colonies, the proportion should be assessed for a sample of nests (50-100 for each visit) well spaced throughout the entire colony, since one species can be clumped in a particular sector of the colony

4. for scarce species (for which the proportion as above would not work well) perform a “total count” during each visit

5. at the peak of colony occupation (usually mid-late breeding season) perform a total count of all the nests

However, it was not possible to obtain precise estimate for some colonies, because they were inaccessible, the nest were not visible, or because they were too large. In these cases, only a gross estimate of the number of nests was done. For some large colonies, their size was estimated by: counting the nests within 20-25 sample plots, squares of 10x10 m each; measuring the total surface of the colony; extrapolating the average density of the plots to the total surface area. Colony size is expressed in number of nests.

Breeding Success

20

Breeding success was recorded for a sample of nests in one of the colonies of the study area, the “focal colony”. The techniques were:1. Establish a sample of nests and mark them. The species of the nest was identified from the observation of

the adults on the nests. 2. Perform 2 visits/week to each nest, and at each visit, check the content of each nest. The breeding success

was expressed as no. of eggs/nest, no. of chicks hatched/nest, and no. chicks fledged/nests. Since the chicks are semi-nidifugous, and cannot be spotted after 15 days old because they escape on the branches surrounding their nests, the no. chicks fledged/nests, actually means “number of chicks alive at about 15 days”

3. When the chicks were about 15 days old (the maximum age they can be caught) capture them and measure tarsus length and body mass. Since tarsus length depends mainly on age, while mass is largely influenced by the amount of food received, the ratio mass/tarsus lenght indicates the condition of the chick. A condition index was calculated for each chick as ratio between the actual mass and the predicted mass for its tarsus length. The predicted mass was calculated from a tarsus-mass regression, based on the data for all the chicks. The condition index equals 1 when the chick mass is exactly average, while values above or below 1 indicate the proportion by which the mass is higher or lower than average.

Breeding success in our study areas was then compared with the success recorded for the same species in other parts of their distributional range (Tab. 3.1).

______________________________________________________________________________

Tab. 3.1. Breeding success of species of herons and egrets, mean value (an d sample size when available), from literature for various areas and years. No data are available for the Chinese Pond Heron.

______________________________________________________________________________No. eggs/ No. chicks No. chicks Country Reference

nest hatched/nest fledged /nest

Little Egret 3.9 3.0 Sichuan (Nanchong 1984) Li et al.,19853.9 Shandong (Penglai 1996) Zhou et al.,19985.2 4.6 Anhui (Chuzhou1981-3) Jiang et al. 19863.6 Henan (Dabieshan1988-9) Zhang et al. 19944.5 ( 314) 3.8 (253) 3.4 (247) Italy Fasola 19984.8 (199) South Spain Hafner et al. in press

4.3-4.6 South Spain Hafner et al. in press3.5-4.7 2.4-3.6 South France Hafner et al. in press

4.3 (256) 3.0 (214) Greece Hafner et al. in press1.5-2.7 (79) Australia Maddock & Baxter 1991

Night Heron 3.9 3.6 Sichuan (Nanchong 1984) Li et al.,19853.3 Shandong (Penglai 1996) Zhou et al. 19983.4 Henan (Dabieshan1988-9) Zhang et al. 19943.4 (213) 2.9 (191) 2.5 (167) Italy Fasola 19983.6 (104) 2.2-2.5 (508) South France Fasola & Hafner 1997

2.5 (146) Greece Katzanzidis et al. 19971.8 (40) Spain Parejo (pers.com.)2.1 (36) Spain Pulido et al. 1993

Cattle Egret 2.9-3.4 (1980) France Hafner (pers. com.)2.7-3.1 (273) Spain Prosper & Hafner 1996

2.3-2.8 (543) Australia Maddock & Baxter 1991

Intermediate Egret 2.0-2.4 (196) Australia Maddock & Baxter 1991______________________________________________________________________________

21

Diet

Waterbird chicks from 10 to 40 days-old, easily regurgitate food when observers approach. During censuses, and while recording breeding success, we collected all the regurgitated items. We tried to collect all the prey items regurgitated by the chicks, and not only the big ones, in order not to bias the sample. Each sample (a pool of all the items collected in the same day, at one colony, and from one species of egret or heron) was preserved and examined in the laboratory.

Foraging habitats

Foraging habitat was recorded for the adults foraging around the same focal colony at which breeding success was being studied and at which samples were being collected. The area over which to record foraging habitats was a 10 km radius circle around the focal colony. Foraging habitat was recorded over the peak period during which most nests have chicks.

On detailed maps of the study area (1:10.000 scale maps if available), we delimited the surfaces of the various types of aquatic habitats used by the egrets and herons, within 10 km from the colony. Each “patch” (i.e. portion of contiguous habitat of the same type) was given a code. These habitats were periodically suveyed, usually 2 times per week, and the number of egrets and herons present in each patch was recorded. All the birds present in the foraging areas were recorded, irrespective of their activity.

Prey biomass in rice paddies

In order to assess the value of rice paddies (the main foraging habitat) to egrets and herons, we collected standard samples of the available prey. A standard sample was obtained with a technique already used elsewhere (Fasola et al. 1996), by 10 sweeps of a long-handled net every 10 m. Each sample was obtained from a different field. Each sweep sampled about 0.5 m P

2P of area, including the entire water column. The net

was effective in sampling all prey, except frogs that could escape faster than the other prey. Frog number was estimated by counting the number moving within a 100 by 1-m strip along the sampling itinerary. The dry mass of a convenient number of prey items was measured in the laboratory. Prey mass was calculated as g dry weight / 100 mP

2P.

Feeding success and prey type

Feeding success and prey type were recorded during focal-animal observations, accomplished during the surveys for recording foraging habitat:1. when an actively feeding bird was encountered in a suitable position (i.e. that is neither so far as to be

difficult to observe, nor so close to be scared by the observer), a focal-animal observation of its feeding activity was performed for a fixed time of 10 min.

2. the bird was observed for 10 min (through a telescope mounted on tripod), and we recorded: feeding technique; number of pecks and on captures; the type and size of prey. Prey size was estimated in relation to the bill of the bird.

Collection of samples for chemical analysis

In order to use colonial waterbirds as bioindicators, and in order to select samples that are homogeneous and comparable for all the study sites, we collected the following materials for chemical analysis.

Eggs. Since pollution levels tend to be more similar within eggs of the same clutch than between eggs from different clutches, to take an egg per nest may not be a good sampling strategy. A strong intra-clutch effect can also be found between the first and last egg in a clutch, this effect will depend on clutch-size, and this source of variability must be taken into account. Since it is not practicable to analyze all the eggs in a clutch , because of cost constraints, during 1999 we tried a sampling procedure intended to assess the relevance of intra-clutch effects, and we collected both single egg taken at random from a nest, and a few entire clutches.

Feathers. Contour feathers were collected from one chick, at the same nests from which the eggs had been sampled.

22

Prey. The 3 main prey of Little Egrets, from nestling regurgitates, were collected. Whenever possible, 10 items of a prey type collected in a particular day constituted one sample. While collecting the prey of the chicks for diet analysis, we separated from these prey, 1 “sample for analysis” per week (each consisting of 10 items each, the most fresh ones) for each of the 3 main prey types (by main we mean in relation to mass). Therefore, 3 samples were collected each week, for the 3 main prey types of that week, whenever possible.

Sediments. Sediments were collected in the different foraging habitats used by the egrets, because differences in placement, water circulation, biological activity above the sediment, can originate variability in contamination. In order to obtain a sample large enough to obtain an adequate picture of the pollutants, we collected several core replicas of sediment in the places where egrets foraged, then we collapsed the replicas into composite samples to be analysed. The restricted amount of resources available for sediment analyses forced us to define a sampling scheme that is clearly suboptimal, but probably enough to reach our objectives, i.e. to estimate the average contamination of the sediment in the wetlands. The samples were collected at the end of the study period, when we already had knowledge (through the foraging habitat records) about the habitats used by the egrets.

Sediments were collected using a core sampler (a plastic tube with 5 cm diameter and 2 cm height) pushed into the mud

Sediment samples were collect by: defining main and secondary habitats; defining how many points (=number of cores obtained) to sample in each habitat; mixing at random from 4 to 12 cores, to obtain composite samples.

Due the logistic problems, the only solution for conservation and transport of the samples was to homogenyse and dry all the wet material (eggs, prey, sediments). Eggs, prey, and sediments, were kept cool, homogenysed, dried in oven (24-48 h at max 50 °C, to constant weight), and stored in poliethylene vials. Feathers were simply stored into polytene envelopes. The samples were split in three parts of similar amounts, one for pesticides and PCB analysis in Spain, one for NAA analysis in Italy, and one for AAS analysis in Italy.

From each egg, a piece of eggshell, centered at the egg equator, was cut and stored for thickness measurement. Polytene vials were used for all the material to be analysed, because they are clean from metals etc. Care was taken that other containers would not contaminate the samples.

Blood slides

Haematological variables can be of great interest in relation to contamination, but adequate blood conservation for detailed analyses requires freezing, and this would have been difficult. Ee included into our sampling scheme only blood slides, that were easy to obtain from the chicks we handled, and easy to conserve. They were obtained from the chicks handled for sampling feathers, and also from any other chick that were handled for recording breeding success. Slides were dried and stained with Giemsa.

23

4.

Breeding and foraging ecology of egretsand herons at the Poyang Lake study area, China

Dai Nianhua, Liu WeiBiological Resources Institute, Jiangxi Acedemy of Sciences, Nanchang, Jiangxi, P.R. China

Fasola Mauro, Giuseppe GaudenziDipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

This chapter summarizes the eco-ethological data collected during 1999 (5 May- 19 June) at the Poyang Lake study area (near Nanchng, Jiangxi, 115°49'-116°46'E, 28°24'-29°46'N), the study area of China that was supposed to be relatively free of pollution. Poyang Lake, the largest freshwater body in China (328,300 ha), is also the most important site for waterfowl in China, and has been established as a NEPA nature reserve.

Colony census

Eight colonies were located within the study area shown in Fig. 4.1 (an area of approximately 120 by 50 km). We presume that no other, undetected colony existed within this area.

A census of the nests (Tab. 4.1) could be accomplished with reasonable accuracy in 4 of these colonies. The small size of the Silver Triangle Bridge colony is probably due to limitation of the colony site, a small and disturbed wood. The other colonies are of medium or large size.

Other colonies were occasionally located during trips outside this area. These colonies seem to be spaced throughout the region at inter-colony distances of about 30 km, and they are of a size comparable to those of the ones we censused. The impression is that the density and size of the colonies within the Poyang lake area is representative of the situation in the whole region. The breeding population is therefore large size, due to the wide surfaces of aquatic habitats, particularly rice paddies, that herons can exploit for foraging.

The Gongquing colony was chosen as the focal study colony, because it was the only one with nests easy to visit, and with large populations of several species. All the following data refer to this colony only.

Fig. 4.1. Poyang lake area, with location and the conventional names of the heronries.

24Silver TraingleBridge

Xihu Garden

Xingizhou

XiangshanForestry Park

Gongqing City

Colony B

Colony B

______________________________________________________________________________Tab. 4.1. Description of the five colonies censused in the Poyang lake area.

______________________________________________________________________________

Colony Xihu Gongqing Xiangshan Silver Triangle Xingizhou Wanli Colony ColonyGarden City Forestry Park Bridge A B

Coordinates 28°39.412’N 29°13.518’N about 28°50’N about 28°20’N 28°56.310’N115°57.049’E 115°49.258’E about 116°10’E about 115°58’E 115°48.820’E

Habitat Small wood Part of large Part of a very Small wood Part of a in a private mixed large juniperus near roads medium-size

bonsai garden woodland and conifer and buildings juniper (mainly (broadleaf, woodland, (broadleaf) plantation

false acacias) bamboo, 3 nuclei at 1 kmNests conifers) each other, Nests

2-10 m high Nests Nests 5-15 m high 5-10 m high2-10 m high 5-15 m high

No. nestsTotal 1,400 2,000 3,000~4,000 170 350 ? ? ?Little Egret 170 580 ++ 20 25 + +Intermediate Egret 165 + 20Great White Egret 50 +Cattle Egret 420 ++Chinese Pond Heron 100 70 + 10 315 + +Night Heron 1130 715 + 120 10 + +

______________________________________________________________________________

Breeding Success

Breeding success was studied in a sample of nests. Priority was given to the Little Egret, whose sample was therefore the largest, while the sample for the Chinese Pond Heron was very small.

The breeding success of each species (Tab. 4.2) can be considered normal, and even higher, compared to the literature data. A comparison with the success of Little Egrets and Night Herons in various parts of their range (Tab. 3.1), shows that at the Gongquing colony the success of these species was at the top end of the range of values recorded elsewhere. This high success preliminarily suggests that no adverse agent (e.g. contaminants) is affecting reproduction in this study area.

______________________________________________________________________________Tab. 4.2. Breeding success in sample nests at the Gongquing colony, mean value (minimum -maximum).

______________________________________________________________________________No. nests No. eggs/ No. chicks No. chicksrecorded nest hatched/nest fledged /nest

Little Egret 67 4.7 (2-6) 4.1 (2-5) 3.7 (1-5)Intermediate Egret 21 3.8 (2-5) 3.4 (2-5) 3.0 (2-5)Cattle Egret 10 3.9 (3-5) 3.4 (2-5) 3.3 (2-5)Chinese Pond Heron 2 5.0 (4-6) 3.5 (3-4) 3.5 (3-4) Night Heron 18 3.4 (3-5) 3.2 (3-4) 3.0 (2-4)______________________________________________________________________________

25

The frequency of clutches of differing size, and their respective success, are shown in Tab. 4.3. Splitting success among clutch sizes may help discover critical factors., e.g. in case of food limitations, larger clutches may have a lower success. No such effect appears in the data of Tab. 4.4. The success remains high even for the larger clutches. Chick condition was estimated only for Little Egrets (Tab. 4.4), and this index as well remained high for the largest clutches. These results again indicate good breeding conditions, and no adverse effect on reproduction.

______________________________________________________________________________

Tab. 4.3. Frequency of nests, and breeding success (mean values), in relation to clutch size.______________________________________________________________________________

Initial clutch size Tot. No.2 3 4 5 6 study nests

______________________________

Little EgretFrequency (%) 2 6 29 52 11 63No. chicks hatched/nest 2.0 2.5 3.7 4.4 4.7No. chicks fledged/nests 1.0 2.5 3.5 4.1 4.0

Intermediate EgretFrequency (%) 5 37 32 26 0 19No. chicks hatched/nest 2.0 2.7 3.7 4.3No. chicks fledged/nests 2.0 2.7 3.0 4.0

Cattle EgretFrequency (%) 0 40 30 30 0 10No. chicks hatched/nest 2.3 3.7 4.3No. chicks fledged/nests 2.0 3.5 3.7

Chinese Pond HeronFrequency (%) 50 50 2

Night HeronFrequency (%) 0 64 29 7 0 14No. chicks hatched/nest 3.0 3.5 4.0No. chicks fledged/nests 2.9 3.0 4.0

______________________________________________________________________________

______________________________________________________________________________

Tab. 4.4. Chick condition index in relation to clutch size, for the Little Egret at the Gongquing colony. Index values >1 indicate larger than average chicks.

______________________________________________________________________________Initial clutch size

3 4 5 6______________________________________________

No. chicks measured 8 18 66 13Mean condition index 0.95 1.01 1.01 0.96S.D. 0.05 0.06 0.08 0.11

26

Prey

Prey were collected from chicks repeatedly from 15 May to 15 June, at the Gongqing City and at the Xihu Garden colonies. The pooled results are shown in Fig. 4.2. The main prey type was fish for every bird species. Shrimps, frogs and tadpoles appear in the diet in decreasing importance. Prey size is shown in Fig. 4.3.

Fig. 4.2. Composition of the diet of the chicks.

Fig. 4.3. Mean prey size.

Foraging habitats

The use of foraging habitat by the egrets and herons was studied by surveying the foraging areas shown in Tab. 4.5, and in Fig. 4.4, during 14 surveys, from 24 May to 19 June.

The distribution of the foraging herons (Tab. 4.6, and same data depicted in Fig. 4.5) shows that Little, Intermediate, and Cattle egrets, and Chinese Pond Herons, forage mostly (for >80% ) on rice paddies. On the other hand, Great White Egrets forages with almost equal frequency in lakes, ponds, and rice paddies, while Night Herons forage mostly in lakes and rivers.

Since most Little Egret foraged in rice fields, most sediment samples were collected there.

_________________________________

27

Tab. 4.5. Habitat types surveyed for foraging herons.

_________________________________Habitat types Surface (ha)Lake 282.37Ponds 74.95Rice paddies 503.36River 106.25Other 0.80Total 967.73_________________________________

Fig. 4.4. Habitat types surveyed, within 7.3 km from the Gongquing colony.

______________________________________________________________________________

28

Tab. 4.6. Distribution of the adult heron and egrets foraging around the Gongquing colony ______________________________________________________________________________

Percentage of birds in each habitat Total no.Lake Pond Rice paddies River Other birds observed

_____________________________________

Little Egret 7 5 88 0 0 214Intermediate Egret 6 7 86 0 0 111Great White Egret 36 29 36 0 0 14Cattle Egret 5 4 89 0 2 261Chinese Pond Heron 14 1 83 1 0 78Night Heron 81 0 0 19 0 43_____________________________________________________________________________

Fig. 4. 5. Distribution of the adult heron and egrets foraging around the Gongquing colony.

Prey biomass in rice paddies

We assessed the biomass available to egrets and herons in the rice paddies, using a standard sampling technique, at 82 sites, each in a different rice field through the rice areas depicted in Fig. 4.4.

The most abundant prey types, both as number and mass, were tadpoles and fish. Fish were small, from 3 to 6 cm in standard length. Also abundant were the larvae of different insect groups (Tab. 4.7). The total biomass in the Nanchnag rice paddies averaged 14.0 g dry weight (Tab. 4.8), an intermediate value in the range of prey biomass values found in the rice fields of several European regions.

______________________________________________________________________________

Tab. 4.7. Composition of the prey available to egrets and herons in the rice paddies.______________________________________________________________________________

Fish Frogs Tadpole Shrimp Crab Coleoptera Hemiptera Odonata Snakelarvae larvae larvae

No. items (%) 21.7 3.4 40.3 0.5 0.2 5.4 21.5 7.1 0.1Biomass (%) 14.4 3.1 58.0 0.5 0.1 1.2 18.0 4.3 0.4

Mean mass of item 0.42 0.56 0.89 0.53 0.53 0.14 0.52 0.38 2.00____________________________________________________________________________________________________________________________________________________________

29

Tab. 4.8. Prey biomass (mean g dry weight/100 m2) available to egrets and herons in the rice padddies at the Gongquing colony, Poyang lake study area. Data for European regions from Fasola et al. (1996).

______________________________________________________________________________Poyang lake NW NE Rhone Delta Axios Delta Ebro Delta

China Italy Italy France Greece Spain

Total biomass 14.0 131.4 26.2 6.2 10.7 13.1No. of samples 82 51 13 31 27 12______________________________________________________________________________

Feeding success and prey type

The feeding success was recorded during 10 min focal animal observations for 41 Little Egrets, 31 Intermediate Egrets, 23 Cattle Egrets, 3 Great White Egrets, and for 3 Chinese Pond Herons, all of which were feeding in rice fields.

We calculated the feeding success (example in Fig. 4.6) and the feeding technique (example in Fig. 4.7). However, the most interesting measure, prey mass intake per unit time, could not be evaluated, because only insufficient data on mean individual prey mass were available, due to the scarcity of data from chick’s prey.

Fig. 4.6. Food intake by adult birds foraging in rice fields.

Fig. 4.7. One aspect of the feeding technique, number of wading paces / min., of the adult birds foraging in rice fields.

30

5.

Ecology of egrets and heronsat the Tai Lake study area, China

Dong YuanhuaInstitute of Soil Science, CAS, Nanjing 210008, P.R. China

Zhang YingmeiDepartment Biology, Lanzhou University, Lanzohu 730000, PR China

Fasola Mauro Dipartimento Biologia Animale, Università di Pavia, Pz. Botta 9, 27100 Pavia, Italy

Taihu region is one of the most productive areas for agriculture, and one of the most economically developed parts of China. Rice fields account for 90% of total farmed land, and the water surface takes 45% of total land. With the rapid economic growth since late ‘70s, water and soil pollution from industry, agriculture and urban waste has been increasing significantly. Therefore, there is a growing urgency to monitor contaminant levels in water and soil, to assess the effects of pollutants to human health and ecosystem health. As it is not possible to measure all pollution parameters because of time-consume and cost, bioindicators are increasingly used to monitor environmental quality and ecosystem-level change. As a first step towards using egrets and herons as bioindicator of pollution at Taihu, we made preliminary survey to find heronries, and then we selected the most suitable one for censusing the breeding population, recording breeding success, investigating prey, and collecting samples, from April to July in 1999 and 2000 respectively. This chapter summarises the results of this research.

Colony census

Five heronries were located in the Taihu area, along the expressway Shanghai-Nanjing (Fig. 5.1, Tab. 5.1). Other colonies were occasionally found during trips in the surrounding region. These heron colonies therefore seem to be spaced throughout the region, at distances of about 30 km to 40 km from each other. The Wuxi colony was the largest, the other colonies were of medium or large size. These five colonies were found at the same sites both in 1999 and in 2000.

Among these colonies, the one located near Wuxi, in the Yuantouzhu Park, was the most suitable one for detailed studies, because of its dense population, species, accessibility. The surrounding wetlands, used by the herons for foraging, are presumably exposed to high pollution from agricultural and industrial activities. All the following data refer to this colony only.

In 1999, the Wuxi colony was located on the slopes of a hill, over a surface of about 27,219 m P

2P, and in a

wood with Cinnamamum camphora and Pinus massoniana. Four species of heron breed: mainly the Night Heron, second in abundance the Little Egret, and a few Chinese Pond Herons and Cattle Egrets. The nests were very dense, and a total count was impossible. In order to estimate the total nest number, five sample-areas were established at random, each of 25x25m, the nests were counted accurately in these sample areas, and the total number in the whole colony was estimated at 9711 nests by extrapolation. The average nest density is about 0.36mP

-2P, and 1.06 per tree. According to the fr33equency ratio recorded for the four species,

the number of nest were: 9250 of Night Herons, 291 of Little Egrets, 170 of Chinese Pond Herons plus Cattle Egrets.

In 2000, the Wuxi colony was split in two subcolonies, at a distance of about 1 km. One subcolony was on the slopes of a hill, approximately 500 m from the 1999 colony site. The second subcolony occupied the top and the slopes of another hill. Both were in woods with dominant Cinnamamum camphora and Pinus massoniana. Four species of herons bred, Night Herons and Little Egrets were dominant, with few Chinese Pond Herons and Cattle Egrets; these two latter species increased after June. The very large size of the colony made it difficult to estimate the total number of nest. To this aim, 20 sample areas were established at

31

random from top to bottom of the hills, each 10m×10m and square in shape. The surface area of the colony was measured on a map drawn from data recorded using a GPS with 3-6 m approximation. The surface was also checked on a 1:10,000 scale map. The nests for the whole and each species were estimated by extrapolation of the average density of the sample areas, to the whole surface. The nests for Night Herons, Little Egrets, Chinese Pond Herons and Cattle Egrets were 30100, 4200, 1000, and 1100 respectively. Therefore the breeding population was much larger than in 1999.

Fig. 5.1. Heronry distribution in the Taihu region

____________________________________________________________________________________Tab. 5.1. Description of heron colonies in the Taihu study area during 2000

____________________________________________________________________________________

Location Number of nests Vegetation AccessNight Little Chinese CattleHeron Egret Pond Heron Egret

Xianren 400 200 100 50 Pine, Chinese Fir easy

Zhengjiang 500 50 500 50 Chinese Fir hard

Changzhou 700 200 2000 100 Chinese Fir hard

Wuxi 30100 4200 1000 1100 Pine, shrub, Camphor very easy

Suzhou 14000 5000 200 1000 Pine, Bamboo, Camphor hard

_____________________________________________________________________________________

32

Breeding Success

Breeding success was investigated at the Wuxi colony, for Night Herons (111 nests studied in 1999, and 214 in 2000), for Little Egret (69 and 85, respectively), of Chinese Pond Heron (6 in 2000). The results are listed in Tab. 5.2.

____________________________________________________________________________________Table 5.2. Breeding success in a sample of nests at the Wuxi colony in the two study years, mean value

(minimum -maximum).____________________________________________________________________________________

Night Heron Little Egret Chinese Pond Heron_________________ __________________ ___________________

1999 2000 1999 2000 1999 2000

No.eggs/nest 3.6 (2-6) 3.4 (2-7) 4.9 (3-7) 5.1 (2-8) - 4.8 (4-6)

No.chicks/nest 2.7 (1-5) 2.8 (1-5) 4.0 (2-7) 4.3 (2-7) - 4.3 (3-5)____________________________________________________________________________________

The breeding success of Night Heron and Little Egret could be considered normal, and even slightly higher for Little Egret, compared to the literature data (see Table 3.1). This suggests that no adverse agent (e.g. contaminants) was severely affecting bird reproduction in this study area.

Prey

Prey were collected from chicks repeatedly from 8 May to 5 June in 1999 and 2000. The main prey type was fish, mainly Carassius auratus, Parabramis pekinensis, that accounted for 100% of the diet of Little Egret chicks, and for 95% of the diet of Night Heron chicks, that also received small amounts of frogs, crustaceans and mammals (Fig. 5.2). Tadpoles, although not representyed in our samples, were sometimes observed among the prey regurgitated by the chicks. The size of the food items of the Little Egret was smaller than for Night Herons (Fig. 5.3), and was mainly small fish and shrimp with body size shorter than 5 cm, including Carassius auratus, Fluta alba, and Misgurnus anguillicaudatus. The size of the food items of Night Herons was larger, the largest ones being 20 to 30 cm in length, including Crassius auratus, Parabramis pekinesis, Misgurnus anguillicaudatus, Fluta alba, Crustacea, Insecta, Rana, and Rodentia.

Fig. 5.2. Frequency of different prey types in the diet of Little Egret and Night Heron chicks, at the Wuxi colony.

33

Fig. 5.3. Mean prey length in the diet of Little Egret and Night Heron chicks, at the Wuxi colony.

Foraging habitats

A sample of water bodies were surveyed 2-5 times, from 3 to 18 June 2000 (Fig. 5.4). These sample habitats were scattered within 13 km from the Wuxi colony, and they represented all the habitat types available to the egrets and herons for foraging. The surface area of the habitats surveyed totalled 881 ha (Tab. 5.3).

The distribution of the foraging herons and egrets among these habitats (Tab. 5.4 and Fig. 5.5) shows that most Little Egrets, Night Herons, and Chinese Pond Herons, foraged on fish ponds and on lake shores. The Night herons exploited the open waters of the lake as well. No data are available for Cattle Egrets, that were never recorded at the sample areas; they probably forage on dry lands. The scarce use of the rice fields is due to their relatively small surface within the study area. On the other hand, fish ponds were intensely used, presumably because they are abundant around the colony, and contain abundant food resources.

Fig. 5.4. Sample foraging habitats, that were surv33eyed around the Wuxi colony.___________________________________________________

Table 5.3. Types of foraging habitats___________________________________________________

Surface(ha)

34

Fish pond 162.4Lake shores 189.4Lake open waters 452.2Pond 1.7Rice fields 12.6River 65.4Total 880.7

___________________________________________________

____________________________________________________________________________________Table 5.4. Distribution of the adult heron and egrets foraging around the Wuxi colony

____________________________________________________________________________________Percentage of birds in each habitat

________________________________________________Fish Lake Lake Pond Rice River Tot.no.birds

pond shores open waters fields observed

Little Egret 46 53 0 0 0 1 153Night Heron 46 24 24 0 0 5 66Cattle Egret 0 0 0 0 0 0 0Chinese Pond Heron 65 12 0 18 6 0 17____________________________________________________________________________________

Fig. 5.5. Distribution of the adult heron and egrets foraging around the Wuxi colony.

35

6.Breeding and foraging ecology of egrets

and herons at the Guandong study area, China

Dai NianhuaBiological Resources Institute, Jiangxi Acedemy of Sciences, Nanchang, Jiangxi, P.R. China

Xavier RuizDipartamento Biologia Animal, Avgda. Diagonal 645, 08028-Barcelona , Spain

DAI AND XAVIER PLEASE WRITE SOMETHING HERE

AT LEAST ABOUT THE DISTRIBUTION OF THE COLONIES WHERE YOU SAMPLED

for the chapter:

7.

Breeding and foraging ecology of egrets and heronsat Haleji study area, Pakistan

Please Xavier:

1. complete the captions to the tabs and figs., as we usually do when we submit a paper to a journal

2. make your additions/crrections to my version (this file), not your old one, in order to maintain the formatting

36

7.

Breeding and foraging ecology of egrets and heronsat Haleji study area, Pakistan

Xavier Ruiz, Gustavo Llorente,P

PCarolina SanperaP

Departament. de Biologia Animal, Avgda. Diagonal 645, 08028-Barcelona , Spain

Lluis Jover Dept. De Salut Pública (Bioestadistica). Universitat de Barcelona

Rahat JabeenP

WWF-Pakistan, 6th

Floor, Block 6,, P.E.C.H.S Shahra-e-faisal, Karachi 75400, Pakistan

Foraging habitat

The Haleji lake is surrounded by arid dry lands where no suitable place for herons feeding activity is available in about 10 km around the colonies, the only exceptions being the Chateji lake which hosts their own heronries, and the paddy fields around the town of Tatta which are 9 km away from the colonies in the Haleji. However, these paddy fields were flooded only from the start of June, i.e. when the breeding season of Little and Intermediate egrets at the Haleji is near the end. Therefore, the only available foraging habitats for the egrets during the breeding season at the Haleji were the lake itself and their surrounding seepage lagoons. Once realized this fact, we undertake regular surveys around the lake to count birds and to identify the feeding areas used by them. Censuses were performed counting birds along the 18 km of perimetral road around the lake shores. This road is elevated 2-3 meters enabling the observation of both, the lake surface and the surrounding seepage lagoons. We performed 10 complete census, five in the early morning and five in the evening. Every census lasted 45 min. in average.

We identifyed a total of 15 feeding areas (Fig. 7.1). The results of the censuses showed that the dominant species during the day was by far the Intermediate egret (Fig 7.2), the other species being more than one order of magnitude below it.

Foraging ecology

To analyze the foraging ecology we performed 15 controls distributed among 7 feeding areas (Fig. 7.3). In every control we observed one to five birds. In each observation we followed a bird during a maximum of 10 minutes or until the bird leaves the feeding area. We defined a patch as the feeding ground used by an egret between two flight activities within an observation. Therefore, every bird observed has used a minimum of one patch and an undetermined maximum. However, not all the patches have been defined as above, since the first patch is defined by the start of the observation and the last one by the end of the observation. To record the feeding activity during an observation we used a standard data sheet which enabled us to register the number of steps, stops, prey captures, prey sizes, and any other foraging activities. The birds were observed using a 20 to 60X spotting scope.

A total of 42 observations were obtained from 7 feeding areas. Most of the observations belonged to Intermediate Egrets (N=35) irrespective of the feeding area controlled. This was because of the great dominance of that species in the diurnal heron community of the lake. In fact, it was the only species present in most of the controls or overly dominant when other species were present. Even though we were not able to obtain large number of observations of Little Egret (no.=7), we have performed a descriptive analysis comparing Intermediate Egret and Little Egret.

37

In order to characterize the depth of the feeding grounds used by both egret species, at the start of every observation we estimated the proportion of the leg that was submerged. The results show that both species used areas where water depth covered between 15 to 45 % of the leg length. No significant differences between species were found (Man Whitney test U=67, p=0.53). Since these results refer to a relative measure of water depth and the leg is longer in the intermediate than in the little egret, this suggests that intermediate egrets can use a wider range of water depths, i.e. that they have larger relative availability of feeding areas.

According to the duration of the observations, designed to be at maximum of 10 min., we can note that little egrets tend to change of feeding area more frequently than intermediate egrets. When comparing the distribution of the duration of observations in each species this trend is very clear and the differences are significant (Mann-Whitney U=46.5, p=0.008)

When assessing the number of patches used by both species during an observation, it seems that Little egrets use less patches in average than intermediate egrets and the same effect appears when comparing the number of unsuccessful patches, i.e., in which no prey were captured. However, when the comparison is done according to the number of unsuccessful patches relative to the total number of patches used by each species, the differences between species were not significant (Mann-Whitney U=82, p=0.21), indicating that the proportion of successful patches was similar for both species. Also, we can compare the number of prey obtained during an observation, either at a global level or according to prey size (small, medium and large). In no case there were significant differences between species.

As noted above, the permanence of Little Egrets in a feeding area is significantly lower than for Intermediate egrets. Such difference can influence some of the apparent differences found later (e.g. the total number of patches used seems to be smaller in Little Egrets). In order to control for this influence we transformed the number of patches and the number of prey obtained, in their respective rates per min P

-1P. Once relativized by

this transformation differences between species were not significant.

During observations the number of steps and stops were also recorded. The number of steps is quite similar between both species, but the number of stops seems smaller for Little than for Intermediate egrets. When transforming these values in rates to remove the effects of duration of observations, the apparent differences disappear (steps per min. P

-1P Mann-Whitney U=91, p=0.35; stops per min P

-1P Mann-Whitney U=92, p=0.37)

suggesting that foraging patterns were similar.

Using only the observations performed on Intermediate Egrets, because there is no enough sample size for Little Egret, we have analysed the possible differences between the feeding areas where the controls were performed. To do this we used two indicative parameters: the number of patches per min. and the number of prey catched per min., in every observation. When comparing those feeding areas which had a large enough sample size (i.e. excluding F0 and F5) we found significant differences between feeding areas. Post hoc comparisons showed that differences are due to lower trophic yield of F4 (Tab. 7.1).

When using patches as the information unit, we can compare both species, because the sample size is then greatly increased, but we cannot use rates, since we have not recorded the amount of time invested per patch. This descriptive analysis suggests very similar performances for both species. In fact, differences were not significant either for number of prey (Mann-Whitney U=3852, p=0.83), nor for number of steps (Mann-Whitney U=3823, p=0.79), nor for number of stops (Mann-Whitney U=3543.5, p=0.34).

The comparison of the proportion of successful patches (i.e. those in which an egret was able to catch at least one prey) also gave very similar values for the two species (Tab. 7.2, Likelihood ratio test=0.005, p=0.94).

Very similar values are also found for the two species when analysing the patches according to the maximum size of the prey catched in them (Likelihood ratio test=1.31, d.f.=3, p=0.73).

In the case of Intermediate Egret for which we have a large enough number of patches, and using the sum of steps and stops as a proxy of the time invested per patch, we can analyse the relationship of time invested with the trophic yield of the patch. The association between both variables is shown in Fig 7.4. If we compare the sum of steps and stops among the patches, grouped in four categories according to the number of prey catched in them (none, 1, 2, 3 or more), we detect significant differences, which are indicative of the positive association between the time invested foraging in patch (for which the sum of steps+stops is a proxy) and the number of prey catched in it (Tab. 7.3). A result in total agreement with the postulates of the foraging ecology theory.

38

Even though we have not a lot of observations on Little Egret, Fig 7.5 shows that the association between number of catched prey and effort invested in a patch is similar to that obtained for the Intermediate Egret

_____________________________________________________________________________________Tab. 7.1.

_____________________________________________________________________________________Preys/min. Patches/min.

AREA CODE n Mean rank n Mean rankF1 5 20.50 5 15.60F2 7 19.43 7 19.86F3 14 17.75 14 16.57F4 6 6.83 6 13.17Total 32 32Kruskall-Wallis test 8.255 1.714d.f.= 3 3P= 0.04 0.63_____________________________________________________________________________________

_____________________________________________________________________________________Tab. 7.2.

_____________________________________________________________________________________ success no prey total

Little Egret count 17 14 31 row% 54.8% 45.2% column% 10.8% 11.0%Intermediate Egret count 141 113 254 row% 55.5% 44.5% column% 89.2% 89.0%

total 158 127 285_____________________________________________________________________________________

_____________________________________________________________________________________Tab. 7.3.

_____________________________________________________________________________________Sum of steps+stops

Number of preys n Mean ranknone 141 88.91 51 139.82 25 190.83 or more 37 214.9Total 254Kruskall-Wallis test 112.38d.f.= 3P= <0.001_____________________________________________________________________________________

Diet

The diet of Intermediate Egret chicks at Haleji lake was analysed through the regurgitates obtained during the sampling of blood and feathers. The regurgitates were collected in plastic bags and transported to the laboratory, where we determined its prey content. All the undigested prey items were individually weighed with a portable balance (0.01 g) and measured using a caliper (0.01 mm). The rest of the regurgitate was also inspected to count the distinguishable prey items and then weighed as a whole. A total of 9 Little Egret chicks with body masses from 105 to 345 g were examined for prey contents, as well as 40 E.i nestlings with body masses between 125 and 420 g. From these we succeeded in obtaining regurgitates for 3 little and 35 Intermediate Egret chicks.

39

The diet composition was only analysed for Intermediate Egrets (Tab. 7.4, 7.5) because of insufficient sample size in the case of Little Egrets.

In order to assess the importance of the different prey items we used the following descriptors : Frequency of occurrence by number and by biomass transformed respectively in percentages, and an index which takes into account the frequency, the abondance and the homogeneity of consumption for the different prey items (Use Index). From these analyses it stands out that the most important prey in number are Caridean shrimps followed by fish (Oreochromis > Colisa = Barbus), the rest being consumed only in small quantities (Fig 7.6). However in biomass the index of use indicates that Oreochromis is the most important prey followed by Caridean shrimps > Colisa > Glossogobius > Barbus > Rana, all the remaining prey being only occasionally represented in the diet (Fig 7.7).

Finally we have analysed the distribution of sizes of the main prey consumed by the Intermediate Egret chicks at the Haleji (Fig 7.8). From these analysis we conclude that most prey are in the range of 2 to 4 cm in length. In the case of Colisa and Caridean shrimps this range corresponds to the sizes found in the lake, but for Oreochromis and Barbus, there were larger specimens at the lake and it was probably operating a prey size selection. This can derive either from the facility of catching smaller exemplars, from active selection by the egrets to feed their chicks or from the place where the prey were taken (the lake surface) which probably only hosts juvenile exemplars of these species.

_____________________________________________________________________________________Tab. 7.4

_____________________________________________________________________________________Pisces

CichlidaeOreochromis niloticus

AnabantidaeColisa lalia

CyprinidaeBarbus phuturio (=Puntius phuturio)

GobiidaeGlossogobius giuris

AmphibiaRanidae

Rana tigrina (adult and juvenile)Arthropoda

CrustaceaCaridean shrimps

InsectaOdonata (adults and larvae)

Hemiptera (Nepidae)OrthopteraColeoptera (adults and larvae)Lepidoptera (larvae)

_____________________________________________________________________________________

_____________________________________________________________________________________Tab. 7.4

_____________________________________________________________________________________Caridean shrimp Colisa Oreochromis Barbus (Puntius) Glossogobius

N Length/N Weight 39/42 21/23 54/57 31/31 7/8Mean length (mm) 34.21 33.81 30.52 26.78 74.74(Std. Dev/Min-Max.) (5.56/22.75-47.41) (3.67/26.79- 38.44) (8.98/20-74.95) (5.7/19.34-46.79) (20.95/33.83-96.94)Mean Weight (g) 0.34 1.28 1.06 0.53 7(Std. Dev/Min-Max.) (0.13/0.12-0.65) (0.48/0.49-2.12) (1.69/0.15-12.59) (0.57/0.18-3.41) (1.92/0.44-15.14)_____________________________________________________________________________________

40

Fig. 7.1

41

Fig 7.2.

Fig 7.3.

42

AREA CODE

F13F5F4F3F2F1F0

Num

ber o

f con

trols

4

3

2

1

0

Fig 7.4.

Fig 7.5.

43

Number of steps

2001751501251007550250

Nu

mb

er o

f st

ops

40

30

20

10

0

# of preys

3 or more

2

1

0

Sum of steps+stops

2001751501251007550250

Nu

mb

er o

f p

reys

20

15

10

5

0

E.intermedia

E.garzetta

Fig. 7.6.

Fig. 7.7.

44

Fig 7.8.

45

8.

Breeding and foraging ecology of egrets and heronsat Taunsa study area, Pakistan

Muhammad AshiqPakistan Agriculture Research Council, P.O. Box 1031, Islamabad 45500, Pakistan

Fasola Mauro, Boncompagni Eleonora, Giuseppe Gaudenzi Dipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

This chapter summarizes the ecological data collected during 2000 (1 May-18 June) at the Taunsa Barrage study area (Pakistan, 30°42’N, 70°50’E). This area includes an artificial barrage on the River Indus, the storage reservoir behind the barrage, the riverside wetlands, and the surrounding area with irrigated crops. This study area was expected to be subject to pollution from agriculture.

Colony census

Within a radius of 20 km from Taunsa Barrage we found two heron colonies (Tab. 8.1). We presume that no other, undetected colony existed within several tents of kilometers in the surrounding areas, that are very dry except for the shores of the River Indus.

One smaller colony we called “canal” (shown in Fig. 8.1 as “colony 2000” ) was located along a large canal; this colony was chosen as the focal ones for study, because it was the only accessible one.

A second colony was located in a large reed bed, at the left-bottom corner of Fig. 8.1 (but not shown in the figure). This colony was inaccessible, and only a rough estimate of its size was possible. During the preliminary survey conducted in 1999, only one big colony had been found, approximately 2 km East of the Colony 2000.______________________________________________________________________________

Tab. 8. 1. Description of the two colonies censused in the Taunsa study area in 2000._____________________________________________________________________________________Colony Canal Reed bedCensus accuracy 95% 70%

Coordinates 30°30.213’N 30°30.136’N70°48.639’E 70°47.236’E

Habitat 10 Acacia trees along an irrigation canal tall reeds, colony about 150x400mNests 2-15 m high Nests 3-4 m high

No. nestsTotal 368 2700

Little Egret 26 50Intermediate Egret 22 70Cattle Egret 305 2000Indian Pond Heron 60Purple Heron 10Night Heron 15 10Javanese Cormorant 500

______________________________________________________________________________

46

Fig. 8.1. Taunsa study area, colony location, and foraging habitats surveyed within 12.5 km from the colony. The area in the map is about 15 by 10 km. The inset shows the location of the study

area within Pakistan (small gray square).

Breeding Success

Breeding success was studied in all the accessible nests (Tab. 8.2). The breeding success of the Little Egret was relatively low, i.e. toward the lower end of the range of values found in literature for different locations and years (see Tab. 3.1). For Night Herons as well the breeding success was low, but only one nest was studied. No comparative data are available in the literature for the other species. This relatively low breeding success may be due either to unfavorable environmental conditions, e.g. food scarcity, or to the effect of contaminants.______________________________________________________________________________

Tab. 8.2. Breeding success in sample nests at the Taunsa colony, mean value (minimum -maximum)______________________________________________________________________________

No. nests No. eggs/ No. chicks No. chicksrecorded nest hatched/nest fledged /nest

Little Egret 6 3.8 (3-5) 3.5 (2-5) 2.5 (2-3)Intermediate Egret 7 3.0 (2-4) 2.3 (1-3) 2.0 (1-3)Cattle Egret 64 3.6 (2-6) 2.9 (1-4) 2.7 (1-4)Night Heron 1 3.0______________________________________________________________________________

47

The frequency of clutches of differing size, and their respective success, are shown in Tab. IV. Splitting success among clutch sizes may help discover critical factors. E.g in case of food limitations, larger clutches may have a lower success. No such effect appears in the data of Tab. 8.3. The success remains high even for the larger clutches. These results again indicate good breeding conditions.

_____________________________________________________________________________________

Tab. 8.3. Frequency of nests, breeding success (mean values), and chick condition index (mean values), in relation to clutch size.

______________________________________________________________________________Initial clutch size Tot. No.

2 3 4 5 6 study nests______________________________

Cattle EgretFrequency (%) 2 47 41 9 2 64No. chicks hatched/nest 1 2.6 3.0 3.2 4.0No. chicks fledged/nests 1 2.6 2.8 2.8 4.0

______________________________________________________________________________

Foraging habitats

The use of foraging habitat by the egrets and herons was studied by surveying the foraging areas shown in in Fig. 8.1, and in Tab. 8.4, during 10 surveys, from 18 May to 13 June.

The distribution of the foraging herons (Tab. 8.5, and same data depicted in Fig. 8.2) shows that a variety of habitats was used for foraging by all the species of egrets and herons. Cattle Egrets used dry lands more than all the others, as it is usual for this species. The data for Purple Herons are biased by the very small number of observed birds, only 2. T limited use of the rice paddies is due to the fact that they were flooded only during the last 10 days of our survey, and later their importance would likely have been greater.

Sediment samples were collected in the ponds, and in the rice paddies, two of the habitats most used by the foraging egrets, and in the canals, that can be considered representative of all the other water bodies since they exchanged the water among all of them

_________________________________

Tab. 8.4. Habitat types surveyed for foraging herons.

_________________________________Habitat types Surface (ha)

Lake 177.90Canals 218.73Ponds 540.12Wetlands 1383.58Rice paddies 170.80Flooded fields 693.91Dry Fields 385.57

Total 3570.61___________________________________

48

_____________________________________________________________________________

Tab. 8.5. Distribution of the adult heron and egrets foraging around the Taunsa colony _____________________________________________________________________________

Percentage of birds in each habitat Total no.Lake Channels Ponds Wetlands Rice Flooded Dry birds

paddies fields fields observed_________________________________________________

Little Egret 9 2 24 21 4 29 10 303Intermediate Egret 8 2 41 29 0 17 4 132Great White Egret 11 11 27 16 9 15 11 55Cattle Egret 2 2 5 55 1 17 17 837Indian Pond Heron 13 0 22 2 8 53 3 64Purple Heron 50 0 0 50 0 0 0 2_____________________________________________________________________________

Fig. 8.2. Distribution of the adult heron and egrets foraging around the Taunsa colony

Feeding success and prey type

The feeding success was recorded during 10 min focal animal observations for 24 Cattle Egrets, 58 Little Egrets, 17 Intermediate Egrets, and 3 Great White Egrets, that were feeding in a variety of habitats.

Their feeding success and some aspects of the feeding technique are shown in Fig. 8.3 and 8.4, respectively.

49

Fig. 8.3. Food intake by adult birds.

Fig. 8.4. One aspect of the feeding technique, number of wading paces / min., of the adult bird.

50

9.

Breeding and foraging ecology of egrets and heronsat Karachi study area, Pakistan

Jabeen Rahat

WWF-Pakistan, 6th

Floor, Block 6,, P.E.C.H.S Shahra-e-faisal, Karachi 75400, Pakistan

Gaudenzi Giuseppe Dipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

This chapter summarizes the ecological data collected during 2000 (1-30 May) at the Karachi study area, Pakistan (24°47’N, 67°11’E; 112). This areas includes the harbour of Karachi, and the neighbour tidal creeks, mangrove swamps and intertidal mudflats. This aream was expected to be subject to considerable urban and industrial pollution. The most abundant egret was Egretta grzetta schistacea, a dark colour morph of the polymorphic species Little Egret.

Colony census

Only one egret colony were present within this study area (Fig. 9. 1), and for a radius of at least 20 km. Nest counts (Tab. 9.1) could be accomplished with reasonable accuracy.

Fig. 9.1. Karachi study area, with the location of the colony, and with the habitat types surveyed, within 2 km from the colony.

51

Code Type

1 open channel

2 mud

3 channel

4 mud

5 creek

6 mangroves

7 mangroves

________________________________________________________

Tab. 9.1. Description of the colony in the Karachi study area, 2000.

________________________________________________________

Colony Ghay Bunder

Coordinates 24°51.431’N, 66°56.053’E

Habitat Mangroves on an island,nests 2-5 m high

No. of nestsTotal 145

Little Egret, dark morph 100Little Egret, white morph 15Intermediate Egret 20Indian Pond Heron 10

________________________________________________________

Breeding Success

Breeding success was studied in all the nests that could be found in the colony, all belonging to the dark morph of the Little Egret. The breeding success (Tab. 9.2). The breeding success of the Little Egret was low, i.e. toward the lower end of the range of values found in literature for different locations and years (see Tab. 3.1). This relatively low breeding success may be due either to unfavorable environmental conditions, e.g. food scarcity, or to the effect of contaminants.

______________________________________________________________________________Tab. 9.2. Breeding success in sample nests at the Karachi colony, mean value (minimum -maximum)

______________________________________________________________________________No. nests No. eggs/ No. chicks No. chicksrecorded nest hatched/nest fledged /nest

Reef Egret 34 3.6 (2-5) 2.9 (1-5) 2.9 (1-5)______________________________________________________________________________

The frequency of clutches of differing size, and their respective success, are shown in Tab. 9.3. Splitting success among clutch sizes may help discover critical factors. E.g in case of food limitations, larger clutches may have a lower success. No such effect appears in the data of Tab. IV. The success remains high even for the larger clutches, and this indicates good breeding conditions as regards food availability.

______________________________________________________________________________

Tab. 9.3. Frequency of nests, and breeding success (mean values), in relation to clutch size.______________________________________________________________________________

Initial clutch size Tot. No.2 3 4 5 study nests

_________________________Reef Egret

Frequency (%) 9 30 52 9 33No. chicks hatched/nest 1.7 2.6 3.3 5.0No. chicks fledged/nests 1.7 2.3 3.5 5.0

______________________________________________________________________________

52

Foraging habitats

The use of foraging habitat by the egrets and herons was studied by surveying the foraging areas shown in Fig. 9.1 and in tab. 9.4, during 4 surveys, from 8 to 23 May. The extension of each habitat is expressed as shore length, and not as surface area, since the egrets exploited all these habitats only along the shores.

The distribution of the foraging herons (Tab. 9.5, and same data depicted in Fig. 9.2) shows that Little Egrets foraged mostly on the surfaces of mud exposed at low tide, and with lesser frequency on the banks of large canals that connected the lagoon to the sea. The Intermediate egrets and the Indian Pond Heron foraged mostly on the same habitats. Therefore, the sediment samples were collected at the two most used habitats, mud and channels.

________________________________________

Tab. 9.4. Habitat types surveyed for foraging herons.________________________________________

Length border of (m)

Channels 1890Muddy shores 740Mangroves 630Total 3260________________________________________

_____________________________________________________________________________

Tab. 9.5.Distribution of the adult heron and egrets foraging around the Karachi colony.

_____________________________________________________________________________Percentage of birds in each habitat Total no.

Channel Mangroves Mud birds observed_____________________________________

Little Egret 37 1 62 216Intermediate Egret 60 10 30 10Indian Pond Heron 60 10 30 10_____________________________________________________________________________

Fig. 9.2. Distribution of the adult heron and egrets foraging around the Karachi colony

53

Feeding success and prey type

All the 89 prey items, collected over 3 weeks throughout the study period, were small fish (Liza abu, Perciformes). The wet weight of these fish prey averaged 13.8 g, the dry weight 3.7 g, and their length ranged from 78 to 23 mm

The feeding success was recorded during 10 min focal animal observations for 8 Little Egrets and 4 Intermediate Egrets, from 8 to 23 May.

We calculated the feeding success (example in Fig. 9.6) and the feeding technique (example in Fig. 9.7).

Fig. 9.3. Food intake by adult birds around the Karachi colony.

Fig. 9.4. One aspect of the feeding technique, number of wading paces / min., of the adult birds foraging around the Karachi colony.

54

10.Heavy metal contaminationin the samples from China

Boncompagni Eleonora, Fasola Mauro,Dipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

Gandini CarloDipartimento Chmica Farmaceutica, Università, Viale Taramelli, I-27100 Pavia, Italy

Orvini EdoardoDipartimento Chmica Generale, Università, Viale Taramelli, I-27100 Pavia, Italy

The samples for chemical analysis of contaminants were collected from three study areas:

1) Pearl River Delta, Guangdong, studied in 2000, and expected to be subject to urban-industrial pollution.

2) Tai Lake, studied in 2000, and expected to be subject to serious pesticide and heavy metal pollution from both agriculture and industry. The samples were collected at the one colony located in the Yuantouzhu Park near Wuxi, and surrounded by wetlands presumably exposed to high pollution from agricultural and industrial activities.

3) Poyang Lake, Jiangxi, studied in 1999, and expected to be free of pollution. The samples were collected at the colony close to the city of Gongquing, north of Nanchang. Despite being close to Lake Poyang, the largest freshwater body and the most important site for waterfowl in China, and a NEPA nature reserve, the area surrounding the Gonquing colony was intensively cultivated, therefore the samples may reflect some exposure to agricultural pollution.

The egret ecology in these study areas are described in the preceding chapters. This chapter summarizes and discusses the main results about the levels of heavy metals and of some other inorganic substance of environmental concern. The rough data are listed in App. A. Further analyses of these results are being devoted to the publications already issued, in press, or in preparation.

Materials

In order to use colonial waterbirds as bioindicators, and in order to select samples that are homogeneous and comparable for all the study sites, we collected the following materials for chemical analysis.

Eggs. Since pollution levels tend to be more similar within eggs of the same clutch than between eggs from different clutches, to take an egg per nest may not be a good sampling strategy. A strong intra-clutch effect can also be found between the first and last egg in a clutch, this effect will depend on clutch-size, and this source of variability must be taken into account. Since it is not practicable to analyze all the eggs in a clutch, because of cost constraints, during 1999 we tried a sampling procedure intended to assess the relevance of intra-clutch effects, and we collected both single egg taken at random from a nest, and a few entire clutches.

Feathers. Contour feathers were collected from one chick, at the same nests from which the eggs had been sampled.

Prey. The 3 main prey of the egrets, from nestling regurgitates, were collected. Whenever possible, 10 items of a prey type collected in a particular day constituted one sample. While collecting the prey of the chicks for diet analysis, we separated from these prey, 1 “sample for analysis” per week (each consisting of 10 items each, the most fresh ones) for each of the 3 main prey types (by main we mean in relation to mass). Therefore, 3 samples were collected each week, for the 3 main prey types of that week, whenever possible.

Sediments. Sediments were collected in the different foraging habitats used by the egrets, because differences in placement, water circulation, biological activity above the sediment, can originate variability in contamination. In order to obtain a sample large enough to obtain an adequate picture of the pollutants, we

55

collected several core replicas of sediment in the places where egrets foraged, then we collapsed the replicas into composite samples to be analysed. The restricted amount of resources available for sediment analyses forced us to define a sampling scheme that is clearly suboptimal, but probably enough to reach our objectives, i.e. to estimate the average contamination of the sediment in the wetlands. The samples were collected at the end of the study period, when we already had knowledge (through the foraging habitat records) about the habitats used by the egrets.

Sediments were collected using a core sampler (a plastic tube with 5 cm diameter and 2 cm height) pushed into the mud on the bottom of the sample wetland.

Sediment samples were collect by: defining main and secondary habitats; defining how many points (= number of cores obtained) to sample in each habitat; mixing at random from 4 to 12 cores, to obtain composite samples.

Due the logistic problems, the only solution for conservation and transport of the samples was to homogenyse and dry all the wet material (eggs, prey, sediments). Eggs, prey, and sediments, were kept cool, homogenysed, dried in oven (24-48 h at max 50 °C, to constant weight), and stored in poliethylene vials. Feathers were simply stored into polytene envelopes

From each egg, a piece of eggshell, centered at the egg equator, was cut and stored for thickness measurement. Polytene vials were used for all the material to be analysed, because they are clean from metals etc. Care was taken that other containers would not contaminate the samples.

Analytical Methods

Two analytical techniques were used for all the sample material, whenever possible: Atomic Adsorption Spectrophotometry (AAS) for cadmium, mercury and lead, and Neutronic Activation Analysis (NAA) for the remaining elements.

The samples were split in two parts of similar amounts, one for NAA analysis, and one for AAS analysis. Unfortunately, some of the feather samples were too small in mass (< 1 mg), could not be further split, and we decided to devote this limited material only to NAA analysis. The analysis so far are complete for NNA, but only about one half of the samples have been processed by AAS, therefore the results summarized here for cadmium, mercury and lead are only partial.

Cadmium and lead were analysed by the Perkin Elmer Aanaliyst 600 atomic adsorption spectrophotometer, equipped with THGA (Transversely Heated Graphite Furnace), longitudinal AC Zeeman-effect background correction and autosampler AS-800.

Mercury was analysed by the Perkin Elmer FIAS-100 equipement for cold vapours generation and the analysis carried out with the Perkin Elmer 3110 Atomic Adsorpion Spectrophotometer.

The control of the instruments and data calculations were performed on PC using the AA WinLab software.

For sample preparation, eggs, preys and sediments must be submitted to a preliminary mineralization treatment before analysis, in order to eliminate organic matter. Mineralization was performed in a CEM-MDS 81D microwave oven, operating in teflon bombs with Newtec Valves, by dissolving samples in 30% nitric acid as described in a previously work (Fasola et al. 1998). The mineralization technique was tested, for recovery of metals, on the biological reference material using as matrix whole egg powder (8415 Reference Material) certified by NIST (National Institute of Standards & Tecnology). All the samples tested for Cd,Cr,Hg and Pb gave recoveres ranging from 98 % and 101%.

Preliminary tests were carried out using standard solutions of pure single element dissolved in nitric acid/water 30% v/v at three different levels. The calibratin curves were found linear for the following ranges respectively, as absolute concentrations: for Cd ( 2-4-6 ppb), for Cr (5-10-20 ppb), for Hg (2-4-8 ppb) and for Pb (3-6-12 ppb) corresponding to a detection limit, on the biological sample, of 0.020 ppm, 0.030 ppm 0.010 ppm and 0.030, for Cd, Cr, Hg and Pb respectively. Estimates were made according to standard addition method (M.Bader,J.Chem.Edu. 57,703 1980) supported by the PC software.

NAA was adopted for analysis of all the others elements (chromim, arsenic, silver, bromium, cobalt, caesium,lantanium, nickel, scandium, selenium, and zinc) in all the samplematerial. For some materials and for the elements that were measured by AAS as well, the NAA results were only confirmatory, while for feathers and for many elements, they were the NAA results were the only ones available.Irradiation of the

56

samples was performed at the irradiation position of the Triga Mark II Nuclear  Reactor of the Pavia University, at a flux of 1x1013n cm-2sec-2. Condition and irradiation time, counting and delay, were chosen according to the nuclear characteristics of the element to be investigated. Gamma ray spectrometry was performed using a high resolution intrinsic Ge detector. Data were processed using a computer program from ORTEC.

All concentrations are expressed in parts per million (μg/g, or ppm) on a dry weight basis.

Data analysis

Sample size in the following tables corresponds to the number of independently sampled nests. For some clutches, more than one egg was collected, and in these cases we computed a mean value for each clutch and we used this value as one sample for the statistics.

Contaminant levels were tested for differences among study areas, and whenever possible among prey types and among sediment origin within each study area, using the Kruskal-Wallis non-parametric variance test, because the value distribution was non-normal. The geometric mean was used throughout as a parameter of central tendency, because the frequency distribution of the concentrations was strongly skewed towards low values. In order to calculate mean concentrations, and in order to perform statistical comparisons, the samples in which a certain element was not found, were attributed a value corresponding to 1/100 of the minimum measured concentration for that element.

Contamination levels in the environment

Eggs. The contamination levels in the eggs of Little Egrets are shown in Tab. I and II.

Scandium and selenium were detected in all samples of the three colonies, arsenic and bromine in all samples from Pearl River Delta and Tai Lake, the only available, cesium and zinc in more than 70% and nickel and silver in less than 20%. of the samples.

There were significant differences in mercury, arsenic, bromine, cobalt, cesium, scandium, selenium and zinc concentration between locations. The highest levels of mercury, cobalt, cesium, scandium and zinc occurred in Little Egret eggs from Poyang Lake, while the highest levels of selenium, arsenic and bromine occurred in samples from Pearl River Delta. Althought there were significant differences among the colony sites for mercury, cesium, scandium, selenium and zinc, the differences were not great, except for zinc, and in general the values were relatively low.

Feathers. The contamination levels in the feathers of Little Egret chicks are shown in Tab. IV; NAA results are the only ones available, pending the conclusion of the analyses. Cobalt was detected in all samples of the three colonies, arsenic and bromine in al samples of those from Pearl River Delta, the only avalaible; cesium,scandium and selenium were found in more than 70% of the samples.

There were significant differences in silver, cobalt, cesium, scandium concentration between locations.

The highest levels of cobalt e scandium occurred in samples from Pearl River Delta, the highest levels of cesium occurred in samples from Poyang Lake and those of silver occurred in Little Egret from Tai Lake. Althought there were significant differences among the colony sites for these metals, the differences were not great, except for cobalt, and the values were again relatively low.

Prey. Contamination levels in the prey collected from the food of Little Egret chicks are shown in Tab. V and VI. There were significant differences in cobalt, cesium, scandium and zinc concentration between locations. The highest levels of cobalt, cesium, scandium occurred in the prey of Little Egrets from Poyang Lake, while the highest levels of zinc occurred in samples from Tai Lake. Althought there were significant differences among the colony sites for these metals, for prey as well the differences were not great and the values very low.

57

Sediments. Contamination levels in the sediments collected in wetlands used by Little Egrets as foraging areas around the colony are shown in Tab. VII and VIII. There were significant differences in chromium, cesium, selenium and zinc concentration between locations. The lowest levels of chromium occurred in Pearl River Delta samples and the values for Poyang lake and Tai Lake were much higher and very similar. The lowest values of cesium and zinc occurred in the Poyang lake samples and the values for Pearl River Delta and Tai Lake were much higher and very similar. The lowest values of selenium occurred in Tai Lake and the concentration for Pearl River Delta and Poyang lake were much higher and very similar.

_______________________________________________________________________________________

Tab. 10.1. Concentration of the most hazardous heavy metals in the eggs of Little Egrets. The values are: no. of samples, (percentage frequency of samples with concentrations above the detection limits, only for samples with no.>5), geometric mean, maximum and minimum values, ppm on dry weight). Nd = no

detected. Ns = non-significant._______________________________________________________________________________________

cadmium chromium mercury lead

Pearl River Delta no.P P2 2 2 2mean Nd 0.053 0.315 0.047min-max 0.05-0.57 0.28-0.35 0.04-0.05

Poyang Lake noP P23 (21.7%) 19 (100%) 19 (100%) 23 (78.3%)mean 0,000001 0.127 0.576 0.221min-max Nd-0.19 0.001-0.46 0.001-2.13 0.08-2.33

Tai Lake no. 2 2 2 2mean Nd 0.122 0.240 0.103min-max 0.10-0.15 0.14-0.41 0.06-0.17

Difference among study areas (P=) N.s N.s 0.02 N.s_______________________________________________________________________________________

_______________________________________________________________________________________Tab. 10.2. Concentration of elements that may be responsible for toxicity at high doses, in the eggs of Little

Egrets. Values as in Tab. I._______________________________________________________________________________________

copper iron manganesePearl River Delta no.P P13 (8%)P P16 (100%)

mean 0.106 114.082min-max Nd-1400.00 53.30-312.00

Poyang Lake noP P11 (100%)P P35 (100%) 19 (100%)mean 13.147 118.572 2.795min-max 4.80-31.60 80.0-217.8 1.30-11.80

Tai Lake no. 7 (14%)P P22 (100%)mean 0.267 177.530min-max Nd-7810.00 104.0-348.8

Difference among study areas (P=) 0.000_______________________________________________________________________________________

58

______________________________________________________________________________________________________________________________________________Tab. 10.3. Concentration of other elements of environmental concern, in the eggs of Little Egrets. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________arsenic silver bromine cobalt cesium lanthanum nickel scandium selenium zinc

Pearl River Delta no.P P17 (100%) 10 (20%) 17 (100%) 17 (59%) 17 (100%) 17 (53%) 16 (0%) 17 (100%) 17 (100%) 17 (71%)mean 0.142 0.00003 40.049 0.004 0.033 0.012 Nd 0.002 3.550 1.07min- max 0.02-0.83 Nd-0.85 9.66-95.67 Nd-0.60 0.004-0.17 Nd-0.36 0.0003-0.06 2.0-5.95 Nd-556

Poyang Lake no.P P 38 (100%) 17 (100%) 23 (100%) 38 (100%) 38 (100%)mean 0.118 0.036 0.027 2.919 59.58min-max 0.06-0.30 0.02-0.35 0.009-0.05 1.97-4.90 43-163

Tai Lake no.P P8 (100%) 18 (0%) 8 (100%) 22 (91%) 22 (91%) 8 (37%) 22 (14%) 22 (100%) 22 (100%) 22 (77%)mean 0.025 Nd 102.957 0.071 0.007 0.012 0.036 0.004 2.689 2.26min-max 0.02-0.60 63.0-182.0 Nd-1.64 Nd-0.06 Nd-46.0 Nd-7.02 0.001-0.16 1.90-3.98 Nd-82

Difference among study areas (P=) 0.024 Ns 0.001 0.004 0.000 Ns Ns 0.000 0.013 0.000______________________________________________________________________________________________________________________________________________

59

_______________________________________________________________________________________Tab. 10.4. Concentration of elements that may be responsible for toxicity at high doses, in the eggs of Little

Egrets. Values as in Tab. I._______________________________________________________________________________________

copper iron manganesePearl River Delta no.P P13 (8%)P P16 (100%)

mean 0.106 114.082min-max Nd-1400.00 53.30-312.00

Poyang Lake noP P11 (100%)P P35 (100%) 19 (100%)mean 13.147 118.572 2.795min-max 4.80-31.60 80.0-217.8 1.30-11.80

Tai Lake no. 7 (14%)P P22 (100%)mean 0.267 177.530min-max Nd-7810.00 104.0-348.8

Difference among study areas (P=) 0.000_______________________________________________________________________________________

_______________________________________________________________________________________Tab. 10.5. Concentration of elements that may be responsible for toxicity at high doses, in the feather of

Little Egrets. Values as in Tab. I._______________________________________________________________________________________

iron manganese copperPearl River Delta NP

oP19 (100%) 19 (0%)

Mean 490.153 NdMin-Max 37.10-4200.00

Poyang Lake NP

oP6 (100%) 6 (100%) 6 (100%)

Mean 140.617 5.994 38.271Min-Max 77.00-410.00 3.800-10.240 28.00-49.00

Tai Lake NP

oP14 (100%)

Mean 192.309Min-Max 109.840-2100.00

Difference among study areas (P=) 0.000_______________________________________________________________________________________

60

______________________________________________________________________________________________________________________________________________Tab. 10.6. Concentration of various elements in the feathers of Little Egrets. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________arsenic silver bromine cobalt cesium lanthanum nickel scandium selenium zinc

Pearl River Delta no.P P19 (100%) 14 (21%) 19 (100%) 19 (100%) 19 (100%) 19 (53%) 19 (21%) 19 (84%) 19 (74%) 19 (68%)mean 0.243 0.0001 74.377 5.160 0.177 0.028 0.090 0.017 0.612 1.8min-max 0.02-4.52 Nd-9.11 42.7-138.0 0.33-15.0 0.045-0.42 Nd-2.70 Nd-74.30 Nd-0.50 Nd-41.10 Nd-103

Poyang Lake no.P P 6 (100%) 6 (100%) 6 (100%) 6 (100%) 6 (100%)mean 0.369 0.027 0.013 1.823 206.1min-max 0.17-0.83 0.01-0.05 0.008-0.03 1.5-2.2 175-236

Tai Lake no. 14 (92%) 14 (100%) 14 (93%) 14 (21%) 14 (93%) 14 (93%) 14 (93%)mean 0.001 0.189 0.020 0.070 0.011 1.338 79.6min-max Nd-0.007 0.10-0.68 Nd-0.07 Nd-19.20 Nd-0.04 Nd-40.43 Nd-320

Difference among study areas (P=) 0.016 0.000 0.000 Ns 0.003 Ns Ns______________________________________________________________________________________________________________________________________________

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_______________________________________________________________________________________Tab. 10.7 Concentration of cadmium, chromium, mercury, and lead in different prey types of Little Egrets.

Values as in Tab. I._______________________________________________________________________________________

cadmium chromium mercury lead

Poyang Lake Fish no. 4 4 4 4mean 0.295 1.339 0.148 1.404min-max 0.16-0.72 0.83-1.93 0.12-0.23 1.01-2.31

Insect larvae no.P P4 4 4 4mean 0.002 0.018 0.0001 0.019min-max 0.00003-0.17 0.0002-1.59 Nd-0.49 0.0002-1.44

Shrimp no.P P4 4 4 4mean 0.028 0.208 0.004 0.115min-max 0.00003-0.39 0.0004-3.83 Nd-0.15 0.0002-2.61

Tadpole,frog no.P P3 3 3 3mean 0.002 0.265 0.001 0.295min-max Nd-0.18 0.0001-12.64 Nd-0.11 0.0002-12.33

Tai Lake Fish, shrimp no. 3 2 2 2mean 0.003 0.293 0.072 0.108min-max Nd-9.00 0.19-0.44 0.05-0.11 0.11-0.11

Difference among study areas (P=) N.s N.s N.s N.s_______________________________________________________________________________________

_______________________________________________________________________________________Tab 10.8. Concentration of elements that may be responsible for toxicity at high doses, in different prey

types of Little Egrets. Values as in Tab. I._______________________________________________________________________________________

Iron Manganese Copper

Poyang Lake Fish no.P P3 2 1Mean 673.862 71.120 27.500Min-max471.50-877.00 56.200-90.00

Shrimp no.P P3 3 1Mean 945.477 212.035 62.0Min-max736.80-1317.00139.60-321.20

Tadpole and frog no.P P1 1Mean 5290.0 104.3Min-max

Tai Lake Fish and shrimp no.P P5 (100%)Mean 433.596Min-max141.0-1500.0

Difference among study areas (P=)_______________________________________________________________________________________

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______________________________________________________________________________________________________________________________________________Tab. 10.9. Concentration of other elements in prey of Little Egrets. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________arsenic silver bromine cobalt cesium lanthanum nickel scandium selenium zinc

Poyang Lake Fish no.P P2 3 2 3 3 3 3mean 1.929 0.697 0.158 1.013 0.298 1.395 155.8min-max 1.20-3.10 0.57-0.82 0.10-0.25 0.83-1.16 0.21-0.37 1.20-1.56 153-158

Shrimp no.P P1 3 3 3 3 3 3mean 0.660 0.869 0.161 1.485 0.338 1.077 83.7min-max 0.82-0.94 0.13-0.20 1.40-1.59 0.30-0.36 0.87-1.27 81-88

Tadpole, frog no.P P1 1 1 1 1 1 1mean 6.900 4.040 1.450 13.000 3.200 2.480 79.9

Tai Lake Fish, shrimp no.P P 5 (20%) 5 (100%) 5 (100%) 3 5 (100%) 5 (100%) 5 (100%)mean 0.00001 0.215 0.019 Nd 0.015 1.319 189.7min-max Nd-0.002 0.10-0.45 0.01-0.04 0.007-0.03 0.47-2.25 163-238

Difference among study areas (P=) 0.004 0.006 N.s 0.004 N.s 0.004______________________________________________________________________________________________________________________________________________

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_______________________________________________________________________________________Tab. 10.10. Concentration of cadmium, chromium, mercury, and lead in sediments. Values as in Tab. I.

_______________________________________________________________________________________cadmium chromium mercury lead

Pearl River Delta Fish pond no.P P3 3 3 3mean 0.537 11.798 0.155 25.779min-max 0.40-0.63 10.47-13.20 0.14-0.18 23.2-28.2

Foraging area no.P P6 (100%) 6 (100%) 6 (100%) 6 (100%)mean 0.355 8.524 0.131 20.311min-max 0.07-0.58 7.14-11.70 0.10-0.28 15.19-26.88

Park no.P P2 2 2 2mean 0.231 8.501 0.136 23.078min-max 0.13-0.41 8.43-8.57 0.11-0.17 22.24-23.94

Poyang Lake Ricefields no.P P2 3 2 2mean 0.251 32.425 0.096 24.753min-max 0.21-0.30 31.99-32.73 0.09-0.11 24.10-25.43

Tai Lake Lake no. 2 2 2 2mean 0.346 54.774 0.117 34.334min-max 0.34-0.36 50.97-58.87 0.11-0.12 30.8-38.18

Difference among study areas (P=) N.s 0.007 N.s N.s_______________________________________________________________________________________

_______________________________________________________________________________________Tab. 10.11. Concentration of elements that may be responsible for toxicity at high doses, in sediments of

Little Egrets. Values as in Tab. I._______________________________________________________________________________________

Iron Manganese Copper

Pearl River Delta Fish pond NP

oP2 1

Mean 45221.68 NdMin-max 40900-50000

Foraging area NP

oP2 2

Mean 37580.05 11.53Min-max 24100-58600 Nd-2770.0

Park NP

oP1 1

geo. Mean 31500.00 NdMin-max

Poyang Lake Ponds NP

oP1 1 1

geo. Mean 3.04 715.77 48.95Min-,ax

Ricefields NP

oP9 (100%) 9 (100%) 6 (100%)

geo. Mean 2.91 321.89 106.98Min-max 2.50-3.46 222.3-362.3 52.34-217.7

Tai Lake Fish ponds NP

oP6 (100%)

geo. Mean 40442.19Min-max 34900-49830

Lake NP

oP4 (100%)

geo. Mean 35301.08Min-max 31500-39925

Difference among study areas (P=) 0.182

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______________________________________________________________________________________________________________________________________________Tab. 10.12. Concentration of other elements in sediments. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________arsenic silver bromine cobalt cesium lanthanum nickel scandium selenium zinc

Pearl River Delta Fish pond no.P P2 2 2 2 2 2 2 2 2mean 16.176 3.983 19.984 10.425 49.115 138.802 16.328 4.274 109.5min-max13.70-19.10 3.16-5.02 19.2-20.8 10.4-10.45 48.15-50.10 114.0-169.0 15.5-17.2 3.74-4.89 79-151

Foraging area no.P P2 2 2 2 2 2 2 2 2 2mean 15.158 0.001 2.005 8.485 7.289 31.786 1.193 11.784 3.343 61.9min-max 11.1-20.7 Nd-0.34 1.57-2.56 3.2-22.5 4.25-12.5 19.85-50.90 Nd-79.90 7.63-18.20 2.86-3.91 30-124

Park no.P P1 1 1 1 1 1 1 1 1 1mean 25.4 Nd 1.810 3.720 4.430 1.955 61.800 8.620 2.397 106.0

Poyang Lake Ponds NP

oP1 1 1 1 1 1 1 1

mean 17.100 11.533 1.560 45.633 10.267 5.023 49.3Ricefields no.P P8 (100%) 7 (100%) 9 (100%) 9 (100%) 9 (100%) 9 (100%) 9 (100%)

mean 12.88 11.212 2.249 40.045 11.481 3.820 55.3min-max 10.37-15.0 8.41-22.13 1.55-5.91 29.2-51.1 9.87-13.60 2.13-4.70 36-71

Tai Lake Ponds no. 6 (100%) 6 (100%) 6 (100%) 6 (100%) 6 (100%) 6 (100%) 6 (100%)mean 0.00003 14.939 7.868 44.891 13.579 2.545 67.2min-max Nd-0.0038 12.9-18.03 7.07-8.99 37.76-51.02 12.25-14.46 2.04-2.80 58-92

Lake no. 4 4 4 4 4 4 4mean 0.001 15.197 7.478 63.451 12.835 3.1 131.4min-max Nd-0.006 14.1-16.82 7.12-8.30 55.7-81.10 11.9-14.17 2.85-3.38 100-162

Difference among study areas (P=) N.s N.s N.s 0.000 N.s N.s N.s 0.007 0.021______________________________________________________________________________________________________________________________________________

66

Evaluation of contamination levels by heavy metals and other inorganic elements

The number of samples analyzed so far, due to incomplete analysis by AAS, in several cases is still too small for a meaningful test of statistical significance. We will discuss the concentration levels in relation to the thresholds that may be harmful to the birds, and that may indicate alarming environmental pollution . We will also try to evaluate the concentration levels found in China, in relation to the levels found in other regions, and to the thresholds above which damage from contamination is suffered.

Cadmium. Birds naturally exposed to high levels of cadmium may have evolved greater tolerance to this element than other bird species, thus it would be difficult to define critical levels of cadmium in tissues that are applicable to all birds. Cadmium concentration in healthy wild birds vary widely among species and among populations within species, with mean levels from 0,1 to 32 ppm wet weight in the liver, and 0,3 to 137 ppm ww in kidney. Cadmium concentrations of < 3 ppm dw in the liver and 8 ppm dw in kidney are considered background concentrations for herons (Scheuhammer 1987), but there are no data about thresholds levels in feathers or eggs and apparently birds do not transfer cadmium into eggs. Herons generally do not accumulate cadmium. Grey herons in the Netherlands (Hontelez et al. 1992), Great bleu herons in Washington and Idaho, (Blus et al. 1985) and Lake Erie, USA (Custer and Mulhern 1983), Little Egrets from Camargue, France (Cosson et al. 1988), Cattle Egret from India (Husain and Kaphalia 1990), Eastern Great White Egrets from central Korea (Honda et al. 1985), and Cattle Egrets from Baja California, Mexico (Mora and Anderson 1995)were all within background concentration for liver and kidney.

Concentrations previously found in healthy populations of Little Egret and of Night Heron in Italy (Tab. VII) were similar to those we found in China, although our data for China refer to eggs, while the data from Italy refer to feathers.

Lead. “Threshold” concentrations for lead poisoning can be defined according to the tissue concentration at which measurable effects occur. Lead absorption may result in a range of sub-lethal effects or in mortality. There are difficulties associated with relating tissue lead concentrations to effect. Different threshold concentrations have been proposed by different authors and have often been chosen to reflect slightly different things, with no standard definitions. However, tissue lead concentration in waterfowl, corresponding to sublethal effect, are at least 2 ppm wet weight for liver, 10 ppm dry weight for bone, and 20 g/dl for blood. There are no data about thresholds levels in feathers or eggs.

Lead is mainly stored in calcareous tissues (Scheuhammer 1987, Cosson 1989). Methallothionein, a metal-binding protein of liver and kidney, preferentially binds zinc and cadmium, and possibly other heavy metals (Nordberg 1972, Osbornet al. 1979, Aaseth and Norseth 1986).

Lead concentrations within this background level were reported in liver of Grey herons in Netherlands (Hontelez et al. 1992), Great blue herons in Washington and Idaho, USA (Blus et al.1985), Black-crowned Night Herons along the Atlantic coast, USA (Custer and Mulhern 1983, Little Egrets from Camargue, France (Cosson et al. 1988), Cattle Egret from India (Husain and Kaphalia 1990), Eatern Great Whit Egrets from Central Korea (Honda et al. 1985) Great Blue Herons, Snowy Egrets and Cattle Egrets from South Florida (Rodgers 1997).

The levels of lead we found in eggs from China are lower than those previously found in Little Egrets and Night Herons in Italy (Tab. VII). Note that our data for China and for Pakistan refer to eggs, while the data from Italy refer to feathers. We could not analyze feathers, because as mentioned before the amount of feathers per sample was too small. Much higher lead levels were found in egret feathers near Hong Kong by Burger and Gochfeld (1993).

Mercury. The concentration of mercury associated with reproductive failure varies by species (Ohlendorf et al. 1978) and a critical mercury level in eggs has not been measured for any heron species. Mercury concentration have been reported in heron eggs (for example by Faber and Hickey 1973, Blus et al. 1985, Hothem et al. 1995, Custer et al. 1997), but are difficult to interpret. The levels of mercury we found in eggs from China are relatively low, and well below concentration that appear detrimental to reproduction (at least 2.5 ppm dw). Levels of mercury higher than ours were found in feathers of herons and egrets in Italy (Tab. 8), in herons and egrets in Hong Kong (Burger and Gochfeld 1993), in adult Great Egrets from Korea (Honda et al. 1986) and in young Cattle Egrets from New-York (Burger et al. 1992). These first two

67

studies sampled heronries near industrial areas. Concentrations similar to ours were found in eggs of Great Blue Herons from two colonies in Washington and Idaho (Blus et al. 1982). One of the colony (Ft.Lewis) was located in the vicinity of areas with severe heavy metals pollution, the other was selcted as the “control” (Tab. 9).

The concentrations associated with sub-lethal or lethal toxic effects in fishes is in range of 5-10 ppm ww. The values we found in fish (prey) from China are below this concentration (colony means = 0.072-0.148 ppm dw).

Arsenic. Arsenic has been rarely determined in aquatic animals. It is a toxic, non-essential element. The concentrations found in wildlife range from non-detectable to 2.9 ppm ww. Therefore, the values we found in tadpoles are rather high.

Copper, manganese, and iron. These elements are essential for life, and only become toxic at high doses. Their absorption is regulated by homeostatic mechanisms (Friberg et al. 1986) Lead and cadmium have unknown physiological roles. At high dose, heavy metals produce lethally toxic. At low doses, they can cause sublethal toxic effects, such as slower reactions to stimuli or weight loss (Honda et al.1990) Toxic effects of heavy metals are also related to their bioavailability (Graveland 1990), and to the organism’s physiological status (Osborn 1979, Blomqvist et al. 1987, Krasowski and Doelma 1990). The interactions between metals are very important as well. Lead, for example, interacts with calcium or phosporus (Graveland 1990) and interactions between cadmium and copper, zinc or selenium are well known (Voogt et al. 1980, Goede and Voogt 1985).

No data have been published about these metals in eggs or feathers of wild bird populations. The concentrations of Copper associated with lethal toxic effects in a littoral decapod, Palaemon elegans, is about 700 ppm (White and Rainbow, 1982). The levels of Copper we found in preys (shrimps) are below these concentrations, but it’s difficult to define absolutely a body concentration range reflecting normal conditions and to make comparisons because of interspecific variability. Variability in metal accumulation strategies among organisms, and in the relative importance of the different metals in organisms sharing the same metal accumulation strategy, makes it difficult the interspecific comparison of metal concentrations even between closely related species (Moore and Rainbow, 1987; Phillips and Rainbow, 1988).

Selenium. Although selenium occurs in many different forms, most of the laboratory data used to derive toxic threshold concentrations, were based on one highly toxic form, selenomethionine (oxidation state = -2). Data were also used from the field, where selenomethionine is believed to be a major, but probably not the sole, chemical form in the foods of birds. High selenium concentrations have not been documented in herons. Background selenium concentration in livers of several species of birds from freshwater averaged 4-10 ppm on d.w and normal egg concentrations were 1-3 ppm on d.w. Selenium concentrations within this background level were reported in eggs and livers of Great Blue Herons from Lake Erie, USA (Nims 1987) and in eggs of Black-crowened Night Herons and Great Egrets from California (Ohlendorf and Marois 1990). Somewhat elevated selenium concentrations were found in Great Blue Heron eggs from the Upper Missispi River, USA (mean = 3.1 ppm dw, Custer et al. 1997) and Indiana, USA (mean = 4.0 ppm dw, Custer et al. 1998), Grey heron (mean = 3.5 ppm dw) and Black-crowned Night Heron eggs (mean = 5.9 ppm dw) from the Delta of the Danube (Fossi et al. 1984), Black-crowned Night Heron eggs (colony means = 2.9-5.7 ppm dw) and Snowy Egret (colony means = 3.0-5.3 ppm dw eggs from San Francisco Bay, California (Hothem et al. 1995).

The level we found in the feather are similar to values found for colonies in New-York, Delaware, Puerto Rico and Egypt.

Threshold for tissue concentrations that seems to affect the health and reproductive success of freshwater fishes is 4 ppm dw. The values we found in fish (prey) from China are below this concentration (colony means = 1.319-1.395 ppm dw)

The concentrations of selenium we found in eggs are rather high, but still lower than the threshold that may affect bird reproduction (about 3 ppm, but on wet weigth).

Zinc. Few data have been published about this metal in eggs of wild bird populations. The concentration of zinc in the egg content of some Mediterranean species is in the range of 37.3-64.2 ppm on d.w. Althought there were significant differences among the colony sites, the values we found in eggs and feathers can be considered normal.

68

Death of the crustacean Palaemon elegans occurs when the zinc body content is about 200 ppm (White and Raimbow, 1982), indicating that much of the extra accumulated zinc is still in metabolically available form. This lethal accumulated body concentration contrasts markedly with the accumulated zinc concentrations in barnacles that typically exceed 10,000 ppm, but are known to be in a detoxified form and therefore not metabolically available (Rainbow, 1987). The levels of Zinc we found in preys (shrimps) are below these concentrations.

_______________________________________________________________

Table 10.13. Concentrations of mercury, cadmium, and lead in feathers of Little Egret and of Night Heron chicks, collected in Italy in 1994. Figures are: geometric mean (ppm on dry weight), and range in parentheses. From Fasola et al. 1998.

_______________________________________________________________Mercury Cadmium Lead

Little Egret 2.587 0.635 4.522(11 samples) (1.296-9.076) (0.360-1.505) (0.803-12.162)

Night Heron 1.982 0.553 3.361(4 samples) (1.244-2.640) (0.400-0.862) (1.343-6.092)_______________________________________________________________

_______________________________________________________________Tab. 10.14. Concentrations of heavy metals in eggs of Great Blue Herons (ppm on wet weight). Figures are: geometric mean (number of positive samples), and

range. Nd= no detected; Na= not analyzed. From Blus et al. 1982________________________________________________________________Colony Year N copper zinc mercury arsenic

Handford 1981 4 1.18 (4) 5.78 (4) 0.17 (4) Na0.65-2.71 5.30-6.37 0.11-0.37

1982 9 0.56 (9) 4.06 (9) 0.02 (6) Nd0.45-0.76 3.59-5.68 Nd-0.10

Ft.Lewis 1982 3 0.46 (3) 3.87 (3) 0.06 (3) Nd0.29-0.59 3.08-4.66 0.04-0.12

_______________________________________________________________

Sediments. The concentrations of arsenic, zinc, cadmium, mercury, lead, copper (samples from Pearl river delta), cobalt (from foraging area and park of Pearl river delta), nickel (samples from foraging area of Pearl river delta) and chromium we found in sediments are lower than critical levels used in the Netherlands for contaminated soil. Copper, cobalt and nickel levels in the remaining part of the sediments samples are below the critical level. Using as reference the more pragmatic Canadian method, the arsenic, cobalt, nickel, silver, zinc lead, cadmium, copper and mercury levels we found both in Pearl river delta sediment and in Tai lake sediment are lower than the trigger concentrations. Chromium concentration from Tay lake samples and arsenic, cobalt, copper and chromium level we found in Poyang lake samples are higher than the critical values. Finally cadmium, lead, mercury and zinc concentrations in sediments from Poyang Lake were lower than the critical values.

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11.Heavy metal contamination

in the samples from Pakistan

Fasola Mauro, Boncompagni EleonoraDipartimento Biologia Animale, Università, Piazza Botta 9, I-27100 Pavia, Italy

Gandini CarloDipartimento Chmica Farmaeutica, Università, Viale Taramelli, I-27100 Pavia, Italy

Orvini EdoardoDipartimento Chmica Generale, Università, Viale Taramelli, I-27100 Pavia, Italy

Ashiq Muhammad, Umar K. Baloch Pakistan Agriculture Research Council, P.O. Box 1031, Islamabad 45500, Pakistan

The samples for chemical analysis of contaminants were collected from three study areas:

1. Karachi Harbour, studied in 2000, and expected to be subject to considerable urban and industrial pollution.

2. Taunsa Barrage, studied in 2000, expected to be subject to pollution from agriculture.

3. Haleji Lake, studied in 1999, expected to be relatively unpolluted.

The egret ecology in these study areas are described in the preceding chapters. This chapter summarizes and discusses the main results about the levels of heavy metals and of some other inorganic substance of environmental concern. The rough data are listed in App. B. Further analyses of these results are being devoted to publications in preparation.

Materials, analytical Methods and Data analysis

The types of materials, the analytical techniques, and the methods used for data analysis, were the same as described in the chapter “Heavy metal contamination in samples from China”.

Contamination levels in the environment

The number of samples analyzed so far, due to incomplete analysis by AAS, in several cases is still too small for a meaningful test of statistical significance. We will therefore simply discuss the concentration levels in relation to the thresholds that may be harmful to the birds, and that may indicate alarming environmental pollution.

Eggs. The contamination levels in the eggs are shown in Tab. I, II and III.

Selenium and iron were detected in all samples from the three study areas, arsenic and bromine in all samples from Karachi and Taunsa, the only ones available, scandium in more than 70% and nichel in less than 20 % of the samples.

There were significant differences in zinc, cadmium, and lead concentration between locations. The highest levels of zinc occurred in Intermediate Egrets from Haleji and those of cadmium and zinc in Little Egrets from Haleji. Althought there were significant differences among the study areas for these metals, the differences were not great, except for zinc , and the values were very low.

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Feathers. The contamination levels in the feathers of Little Egret chicks are shown in Tab. IV and V; NAA results are the only ones available, pending the conclusion of the analyses.

There were significant differences in bromine, cobalt, cesium and copper concentration between locations. The highest levels of bromine and cesium occurred in Little Egrets from Karachi, the highest levels of cobalt in Little Egrets from Taunsa, and those of copper in Intermediate Egrets from Haleji. High concentrations of iron were found in the samples from Karachi and Taunsa.

Prey. Contamination levels in the prey collected from the food of Cattle Egret chicks are shown in Tab. VI, VII, VIII. Again, high concentrations of iron were found.

There were significant differences in chromium, mercury and lead concentration between the three locations. The highest levels occurred in samples from Karachi.

Sediments. Contamination levels in the sediments collected in wetlands used by Little Egrets, Intermediate Egrets and Cattle Egret as foraging areas around the colony are shown in Tab. IX, X, XI

There were significant differences in bromine, cesium, lanthanium cadmium and mercury concentration between the three locations. The highest levels of bromine, cesium, cadmium and mercury occurred in samples of Karachi and those of lanthanium in samples from Taunsa.

_____________________________________________________________________________________Tab. 11. 1. Concentration of the most hazardous heavy metals in the eggs. The values are: no. of samples.

(percentage frequency of samples with concentrations above the detection limits. only for samples with no.>5). Geometric mean. maximum and minimum values. ppm on dry weight). Nd = no detected. Ns = non-significant.

_____________________________________________________________________________________Cadmium Chromium Mercury Lead

Haleji lake Little Egret no. 8 (100%) 8 (100%)Mean 0.167 0.45Min-Max 0.06-0.43

0.29- 0.57

Intermediate Egret no.P P8 (0%) 8 (100%) 8 (100%) 8 (25%)Mean Nd 0.077 0.27 0.00003Min-Max 0.06-0.10 0.14-0.53 0.000002-0.15

Karachi Little Egret no.P P4 (0%) 4 (100%) 4 (100%) 4 (75%)Mean Nd 0.17 0.16 0.004Min-Max 0.04-0.66 0.14-0.17 0.000002-0.05

Taunsa Little Egret no.P P1 1 1 1Mean Nd

0.077 0.1993 0.18

Cattle Egret no.P P1 1 1 1Mean Nd 0.06 0.03 0.11

Difference among study areas (P=) 0.022 Ns Ns 0.022_____________________________________________________________________________________

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_____________________________________________________________________________________Tab 11.2. Concentration in eggs of elements that may be responsible for toxicity at high doses.

Values as in Tab. I._____________________________________________________________________________________

Iron Manganese Copper

Haleji lake Intermediate Egret no.P P20 (100%) 14 (100%) 9 (100%)Mean 95.92 1.702 11.133Min-max 57.8-170.3 0.9-5.2 5.69-15.40

Little Egret no.P P8 (100%)Mean 113.16Min-max 87.9-172.0

Karachi Little Egret no.P P16 (100%) 17 (12%)Mean 179.26 0.169Min-max 76.4-741.0 Nd-3.30

Taunsa Cattle Egret no.P P10 (100%) 8 (0%)Mean 119.45 NdMin-max 83.5-155.0

Little Egret no.P P4 (100%) 4 (0%)Mean 151.90 NdMin-max 105.3-221.0

Difference among study area (P=) Ns Ns_____________________________________________________________________________________

72

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______________________________________________________________________________________________________________________________________________Tab 11.3. Concentration of other elements of environmental concern in eggs . Values as in Tab. I.

______________________________________________________________________________________________________________________________________________

Arsenic Silver Bromine Cobalt Cesium Lanthanum Nickel Scandium Selenium Zinc

Haleji lake Little Egret no. 8 (100%) 1 8 (100%) 8 (100%)Mean 0.043 0.0160 2.275 45.90Min-max 0.02-0.10 1.7-3.4 25.9-65.9

Intermediate Egret no. 17 (100%) 14 (100%) 20 (100%) 20 (100%)Mean 0.063 0.029 2.170 47.58Min-max 0.03-0.16 0.02-0.04 1.00-3.46 29.8-90.8

Karachi Little Egret no. 18 (100%) 12 (8%) 18 (100%) 16 (44%) 16 (81%) 18 (28%) 16 (13%) 16 (94%) 16 (100%) 16 (63%)Mean 0.035 0.000006 44.58 0.001 0.009 0.002 0.041 0.003 3.226 0.36Min-max Nd-1.32 Nd-0.63 29.1-98.0 Nd-0.68 Nd-0.135 Nd-0.48 Nd-22.90 Nd-0.036 1.69-8.37 Nd-329.0

Taunsa Little Egret no. 4 (100%) 2 4 (100%) 4 (100%) 4 (50%) 4 (50%) 4 (0%) 4 (100%) 4 (100%) 4 (100%)Mean 0.006 Nd 44.45 0.035 0.019 0.009 Nd 0.013 2.908 6.36Min-max Nd-0.34 18.5-76.3 0.02-0.05 0.01-0.03 Nd-0.20 0.006-0.03 1.19-4.14 1.10-28.10

Cattle Egret no. 10 (100%) 7 (14%) 10 (100%) 10 (60%) 10 (100%) 10 (30%) 10 (0%) 10 (100%) 10 (100%) 10 (90%)Mean 0.003 0.000014 10.24 0.002 0.013 0.003 Nd 0.007 2.580984 8.72Min-max Nd-0.22 Nd-0.88 4.89-72.60 Nd-0.19 0.005-0.02 Nd-0.25 0.001-0.04 2.00-3.76 Nd-63.0

Difference among study areas (P=) Ns Ns Ns Ns Ns Ns Ns Ns Ns 0026______________________________________________________________________________________________________________________________________________

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_______________________________________________________________________________________Tab 11.4. Concentration in feathers of elements that may be responsible for toxicity at high doses.

Values as in Tab I._______________________________________________________________________________________

Iron Manganese Copper

Haleji lake Intermediate Egret no.P P3 3 3Mean 45.3 2.17 39.15Min-max 41-54 1.1-5.3 10.23-88.76

Little Egret no.P P3 3 3Mean 72.87 2.71 11.08Min-max 43-120 1.6-4.9 6.15-16.52

Karachi Little Egret no.P P11 (100%) 11 (9%) Mean 541.7 0.16Min-max 96-2130 Nd-36100

Taunsa Cattle Egret no.P P13 (100%) 10 (10%)Mean 636.8 0.15Min-max 110-2070 Nd-5550

Little Egret no.P P3 2Mean 233.33 NdMin-max 70-695

Difference among study area (P=) 0.014_______________________________________________________________________________________

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_______________________________________________________________________________________________________________________________________________Tab. 11.5. Concentration of various elements in feathers. Values as in Tab. I.

_______________________________________________________________________________________________________________________________________________Arsenic Silver Bromine Cobalt Cesium Lanthanum Nickel Scandium Selenium Zinc

Haleji lake Little Egret no. 3 3 3 3Mean 0.13 0.011 1.711 154Min-max 0.05-0.23 0.007-0.02 1.37-2.30 123-184

Intermediate Egret no. 3 3 3 3Mean 0.05 0.005 1.154 214Min-max 0.03-0.07 0.004-0.005 0.87-1.36 186-264

Karachi Little Egret no. 12 (100%) 12 (8%) 12 (100%) 12 (100%) 12 (83%) 12 (17%) 12 (0%) 12 (75%) 12 (83%) 12 (67%)Mean 0.042 0.00001 65.89 7.25 0.07 0.002 Nd 0.004 1.438 3Min-max Nd-2.62 Nd-1.36 40.2-96.4 2.59-15.9 Nd-0.57 Nd-1.80 Nd-0.39 Nd-23.2 Nd-1710

Taunsa Little Egret no. 3 1 3 3 3 3 3 3 3 3Mean 0.014 Nd 22.22 9.10 0.0005 0.115 Nd 0.019 9.017 0.029Min-max Nd-1.12 14.8-39.0 4.09-19.3 Nd-0.09 Nd-2.98 0.009-0.03 3.35-27.7 Nd-113

Cattle Egret no. 13 (100%) 9 (11%) 13 (100%) 13 (100%) 13 (85%) 13 (39%) 13 (8%) 13 (77%) 13 (100%) 13 (46%)Mean 0.003 0.00001 21.95 8.47 0.05 0.008 0.035 0.006 7.46 0.17Min-max Nd-1.23 Nd-5.05 10.5-37.0 5.98-15.5 Nd-0.40 Nd-1.46 Nd-113.0 Nd-0.498 3.18-21.7 Nd-428

Difference among study area2s (P=) Ns Ns 0.009 0.025 0.041 Ns Ns Ns Ns Ns_______________________________________________________________________________________________________________________________________________

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_______________________________________________________________________________________Tab 11.6. Concentration of cadmium. chromium. mercury. and lead in different prey types. Values as in

Tab. I._______________________________________________________________________________________

Cadmium Chromium Mercury Lead

Haleji lake Shrimp Intermediate Egret no.P P3 3 3 3Mean 0.05 0.26 0.12 0.30Min-Max 0.04-0.07 0.24-0.27 0.10-0.14 0.19-0.63

Karachi Fish Little Egret no.P P3 3 3 3Mean 0.10 16.54 0.57 4.62Min-Max 0.07-0.13 10.55-24.91 0.53-0.64 3.59-6.37

Taunsa Insect Cattle Egret no.P P2 2 2 2Mean 0.06 2.23 0.02 0.89Min-Max 0.03-0.12 1.48-3.35 0.02-0.03 0.87-0.90

Difference among study area (P=) Ns 0.044 0.044 0.044_______________________________________________________________________________________

_______________________________________________________________________________________Tab 11.7. Concentration of elements that may be responsible for toxicity at high doses, in preys of Cattle

Egret. Values as in Tab I._______________________________________________________________________________________

Iron Manganese Copper

Taunsa Insect no.P P2 2Mean 1929.5 7.72Min-max 1700-2190 Nd-1240.0

Fish no.P P1 1Mean 1046.3 NdMin-max

Frog no.P P1 1Mean 701.0 NdMin-max

Mice no.P P1 1Mean 1620.0 NdMin-max

_______________________________________________________________________________________

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______________________________________________________________________________________________________________________________________________Tab. 11.8. Concentration of other elements in prey of Cattle Egrets. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________Arsenic Silver Bromine Cobalt Cesium Lanthanum Nickel Scandium Selenium Zinc

Taunsa Insect no. 2 2 2 2 2 2 2 2 2 2Mean 0.03 Nd 29.04 1.45 0.37 1.90 Nd 0.68 1.98 71.50Min-max Nd 25.10 1.38 0.35 1.63 0.58 1.13 28.40

0.71 33.60 1.53 0.39 2.21 0.79 3.49 180.00

Fish no. 1 1 1 1 1 1 1 1 1 1Mean 1.35 Nd 15.30 0.97 0.23 0.45 Nd 0.16 2.76 78.00

Frog no. 1 1 1 1 1 1 1 1 1 1Mean 0.40 Nd 12.60 0.67 0.28 0.62 Nd 0.26 2.09 77.90

Mice no. 1 1 1 1 1 1 1 1 1 1Mean 0.54 Nd 10.90 1.51 0.35 1.15 17.10 0.51 2.92 51.50

______________________________________________________________________________________________________________________________________________

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_______________________________________________________________________________________Tab 11.9. Concentration of cadmium, chromium, mercury, and lead in sediments. Values as in Tab. I.

_______________________________________________________________________________________Cadmium Chromium Mercury Lead

Karachi Ghas Bunder mud no.P P3 3 3 3Mean 0.205 32.86 1.53 18.96Min-Max 0.12-0.32 18.77-45.09 0.78-2.67 6.24-47.72

Taunsa Channel no.P P3 3 3 3Mean 0.068 16.992 0.00001 4.18Min-Max 0.06-0.09 15.77-19.15 Nd-0.020 3.84-4.61

Difference among study area (P=) 0.05 Ns 0.05 Ns

_______________________________________________________________________________________

_______________________________________________________________________________________Tab 11.10. Concentration in sediments of elements that may be responsible for toxicity at high doses.

Values as in Tab I._______________________________________________________________________________________

Iron Manganese Copper

Karachi Channel no.P P2 2Mean 40987 7.90Min-max 37500-44800 0.0-1300.0

Mud no.P P1 1Mean 15900 NdMin-maxMax

Taunsa Channel no.P P1 1Mean 39100 2160.0Min-max

Ponds no.P P1 1Mean 36100 3760.0Min-max

9Ricefield no.P P1 1

Mean 38900 NdMin-max

Difference among study area (P=) Ns Ns_______________________________________________________________________________________

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______________________________________________________________________________________________________________________________________________Tab 11.11. Concentration of other elements in sediments. Values as in Tab. I.

______________________________________________________________________________________________________________________________________________Arsenic Silver Bromine Cobalt Cesium Lanthanum Nickel Scandium Selenium Zinc

Karachi Channel no. 2 2 2 2 2 2 2 2 2 2Mean 11.94 0.001 15.91 20.34 9.80 27.53 54.25 13.27 3.16 102.74Min-max 7.46-19.1 Nd-0.28 7.67-33.0 18.8-22.0 9.79-9.8 22.1-34.3 47.4-62.1 11.5-15.3 2.91-3.43 88.7-119.0

Mud no. 1 1 1 1 1 1 1 1 1 1Mean 4.51 Nd 23.10 6.46 2.19 33.60 38.80 6.30 2.98 7.23

Taunsa Channel no. 1 1 1 1 1 1 1 1 1 1Mean 4.12 Nd 4.51 12.30 4.05 94.40 Nd 15.80 8.47 54.80

Ponds no. 1 1 1 1 1 1 1 1 1Mean 4.37 2.55 13.10 4.86 49.25 89.60 14.00 4.16 12.10

Ricefield no. 1 1 1 1 1 1 1 1 1 1Mean 6.30 0.84 2.84 15.60 7.40 53.50 49.00 15.10 3.24 48.50

Difference among study areas (P=) Ns Ns 0.050 Ns 0.050 0.050 Ns Ns Ns Ns

______________________________________________________________________________________________________________________________________________

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Evaluation of contamination levels by heavy metals and other inorganic elements

We try to evaluate the concentration levels found in Pakistan, in relation to the levels found in other regions, and to the thresholds above which damage from contamination is suffered.

Cadmium. Birds naturally exposed to high levels of cadmium may have evolved greater tolerance to this element than other bird species, thus it would be difficult to define critical levels of cadmium in tissues that are applicable to all birds. Cadmium concentration in healthy wild birds vary widely among species and among populations within species, with mean levels from 0,1 to 32 ppm wet weight in the liver, and 0,3 to 137 ppm ww in kidney. Cadmium concentrations of < 3 ppm dw in the liver and 8 ppm dw in the Kidney are considered background concentrations for herons (Scheuhammer 1987), but there are no data 99about thresholds levels in feathers or eggs and apparently birds do not transfer cadmium into eggs. Herons generally do not accumulate cadmium. Grey herons in the Netherlands (Hontelez et al. 1992), Great bleu herons in Washington and Idaho, (Blus et al. 1985) and Lake Erie, USA (Custer and Mulhern 1983), Little Egrets from Camargue, France (Cosson et al. 1988), Cattle Egret from India (Husain and Kaphalia 1990), Eastern Great White Egrets from central Korea (Honda et al. 1985), and Cattle Egrets from Baja California, Mexico (Mora and Anderson 1995)were all within background concentration for liver and kidney.

Concentrations previously found in healthy populations of Little Egret and of Night Heron in Italy (Tab. VII) were higher to those we found in Pakistan.

Lead. “Threshold” concentrations for lead poisoning can be defined according to the tissue concentration at which measurable effects occur. Lead absorption may result in a range of sublethal effects or in mortality. There are difficulties associated with relating tissue lead concentrations to effect. Different threshold concentrations have been proposed by different authors and have often been chosen to reflect slightly different things, with no standard definitions. However, tissue lead concentration in waterfowl, corresponding to sublethal effect, are at least 2 ppm wet weight for liver, 10 ppm dry weight for bone, and 20 g/dl for blood. There are no data about thresholds levels in feathers or eggs.

Lead is mainly stored in calcareous tissues (Scheuhammer 1987, Cosson 1989). Methallothionein, a metal-binding protein of liver and kidney, preferentially binds zinc and cadmium, and possibly other heavy metals (Nordberg 1972, Osbornet al. 1979, Aaseth and Norseth 1986).

Lead concentrations within this background level were reported in liver of Grey herons in Netherlands (Hontelez et al. 1992), Great blue herons in Washington and Idaho, USA (Blus et al.1985), Black-crowned Night Herons along the Atlantic coast, USA (Custer and Mulhern 1983), Little Egrets from Camargue, France (Cosson et al. 1988), Cattle Egret from India (Husain and Kaphalia 1990), Eatern Great Whit Egrets from Central Korea (Honda et al. 1985) Great Blue Herons, Snowy Egrets and Cattle Egrets from South Florida (Rodgers 1997).

The levels of lead we found in eggs from Pakistan are lower than those previously found in Little Egrets and Night Herons in Italy (Tab. VII). Note that our data for China and for Pakistan refer to eggs, while the data from Italy refer to feathers. We could not analyze feathers, because as mentioned before. the amount of feathers per sample was too small. Much higher lead levels were found in egret feathers near Hong Kong by Burger and Gochfeld (1993).

Mercury. The concentration of mercury associated with reproductive failure varies by species (Ohlendorf et al. 1978) and a critical mercury level in eggs has not been measured for any heron species. Mercury concentration have been reported in heron eggs (for example by Faber and Hickey 1973, Blus et al. 1985, Hothem et al. 1995, Custer et al. 1997), but are difficult to interpret. The levels of mercury we found in eggs from Pakistan are relatively low, and well below concentration that appear detriment reproduction (at least 2.5 ppm dw). Levels of mercury higher than ours were found in feathers of herons and egrets in Italy (Tab. 8), in herons and egrets in Hong Kong (Burger and Gochfeld 1993), in adult Great Egrets from Korea (Honda et al. 1986) and in young Cattle Egrets from New-York (Burger et al. 1992). These first two studies sampled heronries near industrial areas. Concentrations similar to ours were found in eggs of Great

81

Blue Herons from two colonies in Washington and Idaho (Blus et al. 1982). One of the colony (Ft.Lewis) was located in the vicinity of areas with severe heavy metals pollution, the other was selcted as the “control” (Tab. 9).

The concentrations associated with sub-lethal or lethal toxic effects in fishes is in range of 5-10 ppm ww. The values we found in fish (prey) from Pakistan (Karachi) are below this concentration ( 0.572 ppm dw).

Arsenic. Arsenic has been rarely determined in aquatic animals. It is a toxic, non-essential element. The concentrations found in wildlife range from non-detectable to 1.35 ppm ww, and the maximum values may be considered rather high.

Copper, manganese, and iron are essential elements that become toxic at high doses. Their absorption is regulated by homeostatic mechanisms (Friberg et al. 1986) Lead and cadmium have unknown physiological roles. At high dose, heavy metals produce lethally toxic. At low doses, they can cause sublethal toxic effects, such as slower reactions to stimuli or weight loss (Honda et al.1990) Toxic effects of heavy metals are also related to their bioavailability (Graveland 1990), and to the organism’s physiological status (Osborn 1979, Blomqvist et al. 1987, Krasowski and Doelma 1990). The interactions between metals are very important as well. Lead, for example, interacts with calcium or phosporus (Graveland 1990) and interactions between cadmium and copper, zinc or selenium are well known (Voogt et al. 1980, Goede and Voogt 1985).

Selenium. Although selenium occurs in many differnt forms, most of the laboratory data used to derive toxic threshold concentrations, were based on one highly toxic form, selenomethionine (oxidation state = -2). Data were also used from the field, where selenomethionine is believed to be a major, but probably not the sole, chemical form in the foods of birds. High selenium concentrations have not been documented in herons. Background selenium concentration in livers of several species of birds from freshwater averaged 4-10 ppm on d.w and normal egg concentrations were 1-3 ppm on d.w. Selenium concentrations within this background level were reported in eggs and livers of Great Blue Herons from Lake Erie, USA (Nims 1987) and in eggs of Black-crowened Night Herons and Great Egrets from California (Ohlendorf and Marois 1990). Somewhat elevated selenium concentrations were found in Great Blue Heron eggs from the Upper Missispi River, USA (mean = 3.1 ppm dw, Custer et al. 1997) and Indiana, USA (mean = 4.0 ppm dw, Custer et al. 1998), Grey heron (mean = 3.5 ppm dw) and Black-crowned Night Heron eggs (mean = 5.9 ppm dw) from the Delta of the Danube (Fossi et al. 1984), Black-crowned Night Heron eggs (colony means = 2.9-5.7 ppm dw) and Snowy Egret (colony means = 3.0-5.3 ppm dw eggs from San Francisco Bay, California (Hothem et al. 1995).

The concentrations of selenium we found in eggs are rather high, but still lower than threshold that may affect bird reproduction (about 3 ppm, but on wet weigth). The level we found in the feather are similar to values found for colonies in New-York, Delaware, Puerto Rico and Egypt.

Threshold for tissue concentrations that seems to affect the health and reproductive success of freshwater fishes is 4 ppm dw. The values we found in fish (prey) from Pakistan (Taunsa) are below this concentration (2.760 ppm dw)

Zinc. Few data have been published this metal in eggs of wild bird populations. The concentration of zinc in the egg content of some Mediterranean species is in the range of 37.3-64.2 ppm on d.w. Althought there 8were significant differences among the colony sites, the values we found in eggs and feathers can be considered normal.

Sediments. The concentrations of arsenic, zinc, cadmium, chromium and lead we found in sediments are lower than critical levels used in the Netherlands for contaminated soil, while cobalt, nickel, mercury and copper levels are higher. Using as reference the more pragmatic Canadian method, the arsenic, cobalt, nickel, silver, zinc, cadmium, mercury and lead levels at both Karachi and Taunsa were lower than the trigger concentrations. Only copper concentration in Taunsa sediment is above the critical level.

82

12.Contamination by organic compounds

in the samples from China

Ruiz Xavier, Sanpera Carolina , Jover Lluis, Llorente GustavoDepartament. de Biologia Animal, Avgda. Diagonal 645, 08028-Barcelona , Spain

An Quiong Institute of Soil Science, CAS, Nanjing 210008, P.R. China

The samples for chemical analysis of contaminants were collected from three study areas:1. Pearl River Delta, Guangdong, studied in 2000, and expected to be subject to urban-industrial

pollution.2. Tai Lake, studied in 2000, and expected to be subject to serious pesticide and heavy metal pollution

from both agriculture and industry. The samples were collected at the one colony located in the Yuantouzhu Park near Wuxi, and surrounded by wetlands presumably exposed to high pollution from agricultural and industrial activities.

3. Poyang Lake, Jiangxi, studied in 1999, and expected to be free of pollution. The samples were collected at the colony close to the city of Gongquing, north of Nanchang. Despite being close to Lake Poyang, the largest freshwater body and the most important site for waterfowl in China, and a NEPA nature reserve, the area surrounding the Gonquing colony was intensively cultivated, therefore the samples may reflect some exposure to agricultural pollution.

The egret ecology in these study areas are described in the preceding chapters. This chapter summarizes and discusses the main results about the levels of organic contaminants. The rough data are listed in App. C. Further analyses of these results are being devoted to the publications in preparation.

Sampling effort was mainly directed to collect eggs of the Little Egret, the most widespread egrets in the region, from different areas. In addition, some Night Heron samples were collected in the Tai Lake study area. The results on Egret’s diet (see chapters 4 and 5) indicate that Little Egrets feed mainly small fish and shrimps (body size <5 cm), including Carassius auratus, Fluta alba, and Misgurnus anguillicaudatus. The prey of the Night Heron is larger (up to 20-30 cm), and include C. auratus, Parabramis pekinensis, Misgurnus anguillicaudatus, Fluta alba, Rana, Insecta, Crustacea and Rodentia.

The organochlorine compounds that were analysed include:

Hexachlorobenzene (HCB). HCB is a fungicide used for seed grains and is an industrial waste product from the manufacture of several chlorinated pesticides. It is also used in the manufacture for tires, and it is present in the herbicide Dacthal and the fungicide pentachloronitrobenzene, and it is persistent in the environment. (Wiemeyer, 1996).

Hexachlorocyclohexanes (HCHs). This pesticide is also known as benzene hexachloride, and occurs as three different isomers, α-, β-,and γ-. The γ- isomer, also known as lindane, is the most active insecticide. Their major uses are on seed and livestock. Lindane is readily metabolised and excreted in birds, minimally accumulated in the tissues, and without implication as a problem in the field (Wiemeyer, 1996).

Cyclodienes.

Heptachlor, heptachlor epoxide: Hepatchlor is an insecticide primarily used to control soil pests. This pollutant is ready metabolised to heptachlor epoxide in vertebrates.

83

Endosulfan: Although is a member of the cyclodiene group, differs in properties and effects. The technical grade consists of two isomers, α- and β-. Endosulfan is rapidly eliminated and does not appear to accumulate in warm-blooded animals.

Dichloro-Diphenil-Trichloroethanes (DDTs): pp’-DDT, pp’-DDE, pp’-DDD

DDT is an organochlorine with insecticidal properties, which came into wide agricultural use in the late 1940s. Catastrophic population declines in certain bird species, notably raptors, and related eggshell thinning were well documented after 1946. It was used extensively in agriculture, but their use has been restricted in most countries, included Pakistan. Nevertheless, DDTs still can be found in the formulation of other insecticides as Dicofol. Technical DDT, the insecticidal formulation applied to the field, consists of several compounds that may be changed or broken down by a number of physical or biological factors in the environment. Of these compounds, only pp’-DDT, pp’-DDD and pp’-DDE have been related to adverse environmental problems. Birds of the Order Ciconiiformes have been reported as very sensitive to DDE-induced eggshell thinning (Custer, 2000).

Polychlorinated Biphenils (PCBs). These are a group of synthetic chlorinated aromatic hydrocarbons. Since, 1930 PCBs have been in general use, having appeared in commercial products including heat transfer agents, lubricants, dielectric agents, flame retardants, plasticizers, and waterproofing materials. Their predominant use has been as insulating and cooling agents in closed electrical transformers and capacitors because their low flammability. Environmental contamination has resulted from several sources including industrial discharge, leaks from closed systems, disposal from sewage treatment plants, and incomplete incineration of PCBs. There are 209 possible congeners of PCBs and some of them could act as a catalyst for many mutagens and carcinogens (Custer, 2000).

Sample preparation and analytical methods

Tab. 12.1 details the samples collected in each of the study areas. In some cases prey samples analysed corresponded to pooled composites.

_____________________________________________________________________________________

Tab. 12.1. Number of samples obtained in China for each study area during 1999 and 2000. In parenthesis: no. of items in the composite samples.

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Tai Lake Poyang Lake Pearl River Delta

Eggs (Nest) Little Egret 24 (36) 19 (38) 10 (20)Night Heron 3

Prey Fish 14 4 (8-12)Shrimps 1 2 (5,8)Fish and shrimp 1Frogs 1 1 (3)Tadpoles 2 (8,11)Odonata 4 (2-11)

Sediments Pond 1Rice field 9Lake 4 2Fishpond 6 3Foraging area 6

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Once collected, whole eggs were frozen for later analysis. When more than one egg was collected from the same nest, a mean value was computed for the nest, and was used for the statistics.

Samples of sediments were taken from different foraging areas used by the egrets, using a 30 cm depth core. Tab. 12.1 indicates places where sediments were collected. Sediments were air-dried under field conditions or, if available, in an oven (50º C) before being taken to the lab for analysis.

Prey samples corresponded to chick regurgitates. When possible prey samples were dried in an oven (50ºC) before transport. When drying was not possible, prey samples were measured, weighed and preserved in alcohol (60) in the field. In the laboratory, prey items were classified and individuals of the same species were pooled to obtain a composite sample. Chemical analysis was usually performed for each prey type separately, but when this was not the case, the results are grouped in Tab. 12. 1.

Chemical analyses of organochlorines were done at the Laboratory of Toxicology (School of Veterinary Science, Universitat Autònoma de Barcelona) following Mateo et al. (1998, 1999).

For the analysis, fish and egg samples were homogenised with anhydrous sodium sulphate, followed by extraction with n-hexane and clean-up with sulphuric acid. The same procedure was used for sediment samples, but without anhydrous sodium sulphate. PCBs#1 and #209 were used as internal standards. High resolution chromatographic analyses and quantification of OC residues followed the corrected Ballschmiter and Zell nomenclature system for PCBs (Guitart et al., 1993). Arochlor 1254 was used to quantify PCBs reported. Recovery of selected pesticides and PCBs were calculated and considered satisfactory (70%-100%), but no corrections were made based on recoveries. Blanks were processed between samples to check the absence of external contamination.

In some eggs, eggshell thickness was measured using a DIGIMATIC counter (Mitutoyo). Accuracy of measure was to the nearest 0.01 mm. In each eggshell, thickness was measured five times at the equator, and the arithmetic mean was obtained.

For descriptive statistics, we computed geometric mean and ranges because of the skewed distributions and those samples in which the compound was not detected were not included. The relationship between organochlorines was assessed by non-parametric Spearman rho statistic; in this analysis non-detected data were replaced by a value equal to half the detection limit. To compare mean eggshell thickness between egg groups we used the non-parametric Mann-Whitney U-test.

Results

In Tab. 12.2 to 12.7, descriptive statisitics are provided for the concentrations of the contaminants in the samples. Concentrations in the Little Egret eggs are expressed both on wet and on dry weight basis, in order to allow a comparison with Night Heron eggs, for which only dry weight is reported. The small sample size and the lack of the wet weight data for the Night Heron precluded further comparisons, and thus, results and discussion sections are mainly devoted to the Little Egret.

Hexachlorobenzene (HCB). Levels of this pollutant in biota and sediments are shown in Tab. 12.2. HCB has been detected in most egg samples, higher levels being found in Little Egret eggs from Tai Lake. All the preys collected at the Poyang had HCB, but a low number of preys in Tai Lake presented this pollutant. With regard to sediments, only those from the Poyang Lake had detectable quantities of HCB.

Hexachlorocyclohexanes (HCHs). HCH compounds were detected in a high proportion of egg samples from Tai Lake and Pearl River Delta, whereas few eggs from the Poyang had levels above detection limits. HCH concentration in eggs form Tai Lake and Pearl River Delta were quite similar.

These pollutants were detected in 26% of preys in Poyang samples and in a 58% in preys from Tai Lake. The concentration in the sediments has shown to be highly variable (Tab. 12.3).

Cyclodienes. Tab. 12.4 lists the concentration of cyclodienes in biota and sediment. The eggs from Tai Lake and Pearl River Delta presented similar levels and cyclodienes were detected in most of the samples, whereas cyclodienes were found only in one egg from Poyang Lake, at a lower concentration. No cyclodienes were detected in prey consumed by the Egrets in the Poyang, but these compounds were

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present in almost all the prey collected at Tai Lake. With regard to sediments, higher levels were found in samples from Tai Lake, followed by those of Poyang Lake and Pearl River Delta.

DDTs and its metabolites. Total DDT levels were similar in the egret eggs from the three areas, being detected in almost all the samples analysed. DDTs were detected also in a high percentage of preys, higher levels being attained by vertebrates, fish and tadpoles. Except for one sample taken in a pond at Poyang Lake that exceeded 48 mg/kg, concentrations in the sediments were low.

As is shown in Tab. 12.6, most of DDT in the eggs corresponded to pp’-DDE, levels of this metabolite being similar in all the egg samples. In the prey, higher pp’-DDE levels were found in fish and tadpoles. The highest DDE levels were found in the sediments from Poyang Lake.

PCBs. PCB levels were higher in the eggs of egrets from Tai Lake, followed by egrets from Pear River delta and Poyang Lake. No PCBs were detected either, in samples of prey or sediments collected at Poyang Lake. Only vertebrate samples from Tai Lake had significant levels of PCBs. These pollutants were detected in sediments from both Tai Lake and Pearl River Delta.

Pollutant ratios

In Tab. 12.8, descriptive statistics for groups of pesticide pollutants different from DDT, the sum of pesticides, sum of organochlorines, and various ratios between pollutants by species and area are provided.

Pesticide pollutants were detected in all the eggs analysed both, from the Poyang Lake and from Pearl River Delta. Only one egg from Tai Lake had levels of pollutants below the limit of detection. The most abundant pesticides were in all the cases DDTs, and in the Poyang and Pearl River Delta these were present exclusively as the pp’-DDE congener. The proportion of PCBs was highest in Tai Lake and Pearl River Delta than in Poyang Lake.

Comparison among the species

In egg samples form Tai Lake, a comparison has been carried out between Little Egrets and Night Heron. The results from the Mann-Whitney test show that DDT levels are significantly higher in the Night Heron (U= 4.00, p=0.008). The DDTs/PCBs ratio was higher also in this species (U= 7.00, p= 0.021).

Comparison among study areas

To compare pollutant levels among different areas, only eggs of Little Egrets have been considered. In Fig. 12.1 to 12.6 are depicted the boxplots of egg concentrations (median, interquartile range, range values and outliers) for different organochlorine compounds in the Little Egrets from the three areas. Significant differences were found for HCB (X P

2P: 7.095, p=0.029) and HCH levels (X P

2P: 6.856, p=0.032),

PCBs (XP

2P: 21.281, p<0.001) and the ratios DDE/DDTs (X P

2P: 19.026, p<0.001), DDTs/ΣPEST (X P

2P: 35,974,

p<0.001) and DDTs/PCBs (XP

2P: 23.840, p<0.001).

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_____________________________________________________________________________________Tab. 12.2. Concentrations of hexachlorobenzene HCB (ng/g) in the samples. The values are: number of

samples, percentage of samples with contaminants above detection limit, geometric mean concentration of the contaminants, minimum an maximum values. All values are expressed as ppb, or ng/g on a dry weight

basis, but for eggs the values are expressed on a wet weight basis (w.w.) as well.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsPoyang Lake Little Egret 19 74 18.0 (ww= 3.3) 1.0-6.5

Tai Lake Little Egret 24 96 30.6 (ww= 6.3 2.2-37.5Night Heron* 3 100 36.2 17.0-93.0

Pearl River Delta Little Egret 10 100 31.1 (ww= 6.0) 3.0-10.3

PreyPoyang Lake Fish 4 100 11.4 4.0-19.0

Shrimps 4 100 15.0 12.0-18.0Tadpoles 2 100 18.5 18.0-19.0Frogs 1 100 17.0 17.0-17.0Odonata 4 100 28.7 14.0-61.0

Tai Lake Fish 14 29 6.7 3.2-16.9Shrimps 1 0Fish and shrimp 1 0Frogs 1 100 7.7 7.7-7.7

SedimentsPoyang Lake Pond 1 100 1.3 1.3-1.3

Ricefield 9 89 1.6 1.3-2.0

Tai Lake Lake 4 0Fishpond 6 0

Pearl River Delta Lake 2 0Fishpond 3 0Foraging area 6 0

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____________________________________________________________________________Tab. 12..3. Concentrations (ng/g) of hexachlorocyclohexane compounds (HCHs), in the samples. Values

as in Tab. 12.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsPoyang Lake Little Egret 19 ( 7) 37 51.9 (ww= 9.6) 4.6-18.3

Tai Lake Little Egret 24 (23) 96 92.0 (ww= 19.2) 3.2-91.8Night Heron* 3 ( 2) 67 411.4 145.0-1167.0

Pearl River Delta Little Egret 10 (10) 100 97.3 (ww= 18.8) 10.3-38.4

PreyPoyang Lake Fish 4 ( 1) 25 11.0 11.0-11.0

Shrimps 4 ( 1) 25 9.0 9.0-9.0Tadpoles 2 ( 1) 50 10.0 10.0-10.0Frogs 1 ( 0) 0Odonata 4 ( 1) 25 14.0 14.0-14.0

Tai Lake Fish 14 ( 8) 57 8.7 2.1-37.2Shrimps 1 ( 1) 100 6.7 6.7-6.7Fish and shrimp 1 ( 0) 0Frogs 1 ( 1) 100 5.9 5.9-5.9

SedimentsPoyang Lake Pond 1 ( 0) 0

Ricefield 9 ( 1) 11 0.9 0.9-0.9

Tai Lake Lake 4 ( 0) 0Fishpond 6 ( 1) 17 26.2 26.2-26.2

Pearl River Delta Lake 2 ( 0) 0Fishpond 3 ( 1) 33 1.4 1.4-1.4Foraging area 6 ( 1) 17 0.8 0.8-0.8

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Tab. 12.4. Concentrations of cyclodiene insecticides in the samples. Values as in Tab. 12.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsPoyang Lake Little Egret 19 ( 1) 5 1.8 (ww= 0.33) 0.3-0.3

Tai Lake Little Egret 24 (23) 96 77.0 (ww= 15.23) 2.9-56.7Night Heron* 3 ( 1) 33 10.00 10.0-10.0

Pearl River Delta Little Egret 10 (10) 100 85.5 (ww= 16.55) 6.2-76.7

PreyPoyang Lake Fish 4 ( 0) 0

Shrimps 4 ( 0) 0Tadpoles 2 ( 0) 0Frogs 1 ( 0) 0Odonata 4 ( 0) 0

Tai Lake Fish 14 ( 1) 7 5.7 5.7-5.7Shrimps 1 ( 1) 100 94.7 94.7-94.7Fish and shrimp 1 ( 1) 100 19.5 19.5-19.5Frogs 1 ( 1) 100 12.5 12.5-12.5

SedimentsPoyang Lake Pond 1 ( 1) 100 160.4 160.4-160.4

Ricefield 9 ( 0) 0

Tai Lake Lake 4 ( 1) 25 396.8 396.8-396.8Fishpond 6 ( 5) 83 55.2 4.0-564.3

Pearl River Delta Lake 2 ( 0) 0Fishpond 3 ( 1) 33 8.0 8.0-8.0Foraging area 6 ( 1) 17 3.0 3.0-3.0

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Tab. 12. 5. Concentrations of DDTs (sum) (ng/g) in the samples. Values as in Tab. 12.2.

_____________________________________________________________________________________no.samples%contaminated mean min-max

EggsPoyang Lake Little Egret 19 (19) 100 3016.5 (ww= 547.8) 268.7-1443.6

Tai Lake Little Egret 24 (23) 96 2094.6 (ww= 426.1) 77.2-1081.7Night Heron* 3 ( 3) 100 4497.4 3203.0-6801.0

Pearl River Delta Little Egret 10 (10) 100 2460.46 (ww= 475.09) 151.24-980.46

PrePoyang Lake Fish 4 ( 4) 100 66.9 38.0-111.00

Shrimps 4 ( 3) 75 10.3 9.0-11.0Tadpoles 2 ( 1) 50 248.0 248.0-248.0Frogs 1 ( 1) 100 8.0 8.0-8.0Odonata 4 ( 1) 25 8.0 8.0-8.0

Tai Lake Fish 14 (13) 93 66.6 8.3-211.7Shrimps 1 ( 1) 100 4.7 4.7-4.7Fish and shrimp 1 ( 1) 100 18.2 18.2-18.2Frogs 1 ( 1) 100 10.8 10.8-10.8

SedimentsPoyang Lake Pond 1 ( 1) 100 48632.0 48632-48632

Ricefield 9 ( 8) 89 3.5 1.5-9.7

Tai Lake Lake 4 ( 4) 100 2.4 0.8-6.0Fishpond 6 ( 1) 17 0.7 0.7-0.7

Pearl River Delta Lake 2 ( 1) 50.0 1.4 1.4-1.4Fishpond 3 ( 0) 0Foraging area 6 ( 1) 16.7 2.7 2.7-2.7

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Tab. 12.6. Concentrations of DDE (ng/g) in the samples. Values as in Tab. 12.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsPoyang Lake Little Egret 19 19) 100 3002.5 (ww= 545.3) 263.1-1439.1

Tai Lake Little Egret 24 (23) 96 2011.2 (ww= 408.4 77.22-1077.8Night Heron 3 ( 3) 100 4402.6 3178.0-6688.0

Pearl River Delta Little Egret 10 (10) 100 2321.9 (ww= 448.4 137.4-945.7

PreyPoyang Lake Fish 4 ( 4) 100 62.8 38.0-94.0

Shrimps 4 ( 3) 75 10.3 9.0-11.0Tadpoles 2 ( 1) 50 158.0 158.0-158.0Frogs 1 ( 1) 100 8.0 8.0-8.0Odonata 4 ( 1) 25 8.0 8.0-8.0

Tai Lake Fish 14 (13) 93 60.8 8.3-184.8Shrimps 1 ( 1) 100 4.7 4.7-4.7Fish and shrimp 1 ( 1) 100 18.2 18.2-18.2Frogs 1 ( 1) 100 10.8 10.8-10.8

SedimentsPoyang Lake Pond 1 ( 1) 100 3165.0 3165.0-3165.

Ricefield 9 ( 8) 89 3.3 1.5-7.

Tai Lake Lake 4 ( 4) 100 2.1 0.8-4.8Fishpond 6 ( 1) 17 0.7 0.7-0.7

Pearl River Delta Lake 2 ( 1) 50 1.4 1.4-1.4Fishpond 3 ( 0) 0Foraging area 6 ( 1) 17 1.0 0.9-0.9

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Tab. 12.7. Concentrations of PCBs (sum) (ng/g) in different samples. Values as in Tab. 12.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsPoyang Lake Little Egret 19 ( 9) 47 20.3 (ww=3.7) 1.0-35.7

Tai Lake Little Egret 24 (23) 96 393.0(ww= 79.0) 18.9-331.7Night Heron 3 ( 3) 100 96.2 8.0-505.0

Pearl River Delta Little Egret 10 (10) 100 240.72 (ww= 46.5) 19.1-107.3

PreyPoyang Lake Fish 4 ( 0) 0

Shrimps 4 ( 0) 0Tadpoles 2 ( 0) 0Frogs 1 ( 0) 0Odonata 4 ( 0) 0

Tai Lake Fish 14 (11) 79 15.6 4.3-76.5Shrimps 1 ( 0) 0Fish and shrimp 1 ( 0) 0Frogs 1 ( 1) 100 10.0 10.0-10.0

SedimentsPoyang Lake Pond 1 ( 0) 0

Ricefield 9 ( 0) 0

Tai Lake Lake 4 ( 4) 100 3.2 1.0-15.7Fishpond 6 ( 2) 33 0.7 0.4-1.2

Pearl River Delta Lake 2 ( 2) 100 0.5 0.5-.5Fishpond 3 ( 1) 33 0.8 0.8-.8Foraging area 6 ( 6) 100 0.7 0.5-.9

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_____________________________________________________________________________________

Tab. 12.8 . Mean concentration (ng/g w.w.) of different organochlorines and ratios among different pollutants in the eggs.

_____________________________________________________________________________________

Poyang Lake Tai Lake Pearl River Delta____________ _________________________________________

Little Egret Little Egret Night Heron Little Egret

N (detec) 19 (19) 24 (23) 3 ( 3) 10 (10)% detected 100 96 100 100

Mean ΣPEST (noDDTs) 4.7 45.8 155.8 45.6Min 0.9 23.5 17.0 27.7Max 24.8 160.5 1270.0 97.2

Mean ΣPEST 553.9 478.3 4853.3 531.3Min 276.7 105.3 3378.0 214.7Max 1445.8 1188.6 8071.0 1031.9

Mean ΣOCs 556.8 576.3 5090.2 580.3min 284.4 192.33386.0 233.9max 1445.8 1472.5 8291.0 1103.6

Mean ppDDE/DDTs 1.0 1.0 1.0 1.0min 1.0 0.8 1.0 0.8max 1.0 1.0 1.0 1.0

Mean DDTs/ΣPEST 1.0 0.9 1.0 0.9min 1.0 0.7 0.8 0.7max 1.0 1.0 1.0 1.0

Mean DDTs/PCBs 260.6 7.1 146.5 10.8min 25.5 0.9 8.3 4.8max 759.3 26.5 400.4 17.2

_____________________________________________________________________________________

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Fig. 12.1. Boxplot of HCB (ng/g) in Little Egrets from the three areas under study.

Fig. 12.2. Boxplot of HCHs (ng/g) in Little Egrets from the three areas under study.

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Fig. 12.3. Boxplot of ΣCyclodiene insecticides (ng/g) in Little Egrets from the three areas under study.

Fig. 12.4. Boxplot of ΣDDTs (ng/g) in Little Egrets from the three areas under study.

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Fig. 12.5. Boxplot of PCBs (ng/g) in Little Egrets from the three areas under study.

Fig. 12.6. Boxplot of the ratio DDTs/PCBs (ng/g) in Little Egrets from the three areas under study.

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Fig. 12.7. Boxplot of several pesticides (ΣPEST excluding DDTs, ΣPEST including DDTs and ΣOCs) in Little Egrets from the three areas under study,

Fig. 12.8. Boxplot of several ratios (ppDDE/DDTs and DDTs/ ΣPEST) in Little Egrets from the three areas under study

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Female effect

In some nests of Little Egrets from different localities, more than one egg was taken to examine the female effect. In the Poyang, five entire clutches were taken (4 clutches of 5 eggs and 1 clutch of 4 eggs). In Tai Lake six nests were sampled taking three eggs per nest. In Pearl River Delta, two eggs were taken in each of the ten nests sampled (see Tab. 12.1). The effect of the laying female on pollutant load in the eggs have been analysed independently for each of the localities. The results of the analysis ANOVA are shown in Tab. 12.9.

Only egrets from the Poyang have shown a significant effect of this factor, intraclutch variability being lower than variability inter-clutches. No such effect was found in any of the other areas.

_____________________________________________________________________________________Tab. 12.9. Results of the ANOVA analyses for the female effect on pollutant concentrations.

_____________________________________________________________________________________F Sig.

Poyang Lake ΣDDTs 38.5 .000ΣPCBs 10.6 .001ΣPESTICIDES 38.1 .000ΣOCS 36.4 .000

Tai Lake ΣDDT .31 .897ΣPCB 2.5 .092ΣPES .26 .929ΣOCS 0.6 .715

Pearl River Delta ΣDDT 2.4 .098ΣPCB 1.2 .403ΣPES 1.6 .238ΣOCS 1.6 .241

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Discussion

Hexachlorobenzene. The HCB is a fungicide used for seed treatment and also it is present as a contaminant in other pesticides. It is not easily bio-degradated and tends to accumulate in sediments and biota owing to its low octanol-water coefficient and low vapour pressure.

HCB levels in the eggs of Little Egrets from the three areas are significantly different (K-W test, P=0.029), those collected at the Poyang Lake showing much lower concentrations than those collected either at Tai Lake or Pearl River Delta, which in turn present quite similar values between them.

The levels in prey, seem to be quite surprising at a first glance, since HCB is present in all preys from Poyang, but only in a few from Tai Lake. Furthermore, the levels accumulated in prey from Poyang were higher than those in prey from Tai Lake.

The fact that sediments of Poyang presented detectable levels of this compound, while it is below the detection limit at the other two sites indicates that sediments of Poyang accumulated higher quantities of this organochlorine, suggesting that HCB pollution is higher in the whole aquatic compartment (sediment and aquatic biota) at Poyang Lake, while it is higher for terrestrial secondary consumers at Tai Lake. Such a situation can only be explained through differences in recent inputs of this pollutant to the aquatic compartment, i.e., at the Poyang Lake the entering of HCB should have been more recent than at Tai Lake, where almost all the compound has been already transfered to the upper levels of the food chain.

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Hexachlorocyclohexanes. The hexachlorocyclohexanes are among the organochlorines showing relatively higher solubilities and vapour pressures. They are readily metabolized and excreted in birds and tend to be minimally accumulated in tissues (Blus et al. 1984). Both, percentages of detection and levels of HCHs were similar in eggs of Little Egrets from Pearl River Delta and Tai Lake, and were significantly lower in egret eggs from the Poyang Lake, following a trend very similar to that obtained for HCB (see above). Levels in eggs of Night Herons from Tai Lake were 4 times higher than those of Little Egrets from the same area. For prey items, concentrations were quite similar between Poyang and Tai Lake, but the percentages of detection were much higher at Tai Lake, indicating a more recent pollutant input, as it is also indicated by one of the sediment samples taken in a fish pond which presented levels much above the others. Therefore, the results obtained for eggs also agree with this scenario, since birds at Poyang presented lower levels probably because they have had more time to metabolize and excrete these compounds since the last input in that ecosystem.

Cyclodienes. These compounds are amongst the most dangerous and persistent pesticides. Their levels are very low at the Poyang Lake and only detected in one egg and in one sediment sample. None of these compounds were detectable in preys from Poyang Lake. This indicates both, that the levels are low but probably recent owing to a very localized source of pollution. Conversely, the levels at Tai Lake and Pearl River Delta are higher and much more widespread for eggs, indicating more generalized and ancient inputs of such pesticides at these areas. However, the fact that sediments of Tai Lake presented detectable levels in 60% of the samples, while it was detectable in less than 20% of sediments from Pearl River Delta indicates that at this area the input of cyclodienes was more ancient than at Tai Lake, where some sediment samples still showed relatively high levels, which have not been yet transferred to the uppermost level of the food chain, but are being incorporated by some of the intermediate levels (e.g. shrimps).

DDTs. DDTs, which are the main indicators of pollution deriving from agriculture treatments, were widely distributed, being detected in most of the samples of either eggs, preys or sediments. Levels in Egret eggs from the three areas did not show statistical differences and most of DDT corresponded to DDE. These two facts are clear indicators of old, intense, generalized and persistent pollution by such compounds. However, it is worth mentioning one sediment sample collected at Poyang lake which showed extremely high levels of DDTs, most of them as p.p.’ DDT, i.e. the non-metabolized original molecule, therefore indicating the recent input of that pesticide in the ecosystem, despite that it was officially banned in China in 1982.

Their distribution among the different compartments follows well a biomagnification process model in which the last pollutant input is relatively old, with most of the compound transferred to the uppermost levels of the food chain. The only exception to this, belongs to Poyang Lake where some tadpoles might accumulate high levels of DDTs. This can be explained because tadpoles feed on suspended sediments bio-turbated by themselves, thus increasing greatly the bioavailability of the pesticide already trapped in the sediment. The fact that most of the pollution accumulated by tadpoles is in the form of p.p.’ DDD, a metabolite of DDT formed by bacteria living in anoxic environments (Matsumura 1992), confirms this hypothesis. Also is to be noted that only 50% of tadpoles presented detectable levels, indicating that DDT accumulation in sediments of Poyang Lake is far from being homogeneous, owing to recent inputs of such pesticides at some places of the lake (see above).

At the other two localities it is important to note that, in average, levels at Pearl River Delta are higher than at Tai Lake.

PCBs. These compopunds are the indicators of organochlorine pollution deriving from industrial sources. Significant differences were found in the levels of PCBs and their detectability according to localities. They reached very low levels in the eggs from Poyang, where only a 50% of the samples presented detectable levels. In LakeTaihu eggs, the mean levels were about 20 times higher than at Poyang and ca. double than at Pearl River Delta. At these two localities, moreover, PCBs were detected in almost all the samples. The same trends were observed in sediment and prey samples, PCBs being undetectable at Poyang. Therefore, the area most affected by “industrial” pollution in China according to our results (Tai

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Lake) does not correspond to the area previously selected and supposed to be the most polluted by industrial activity, i.e. the Pearl River Delta (Pearl River Delta).

When considering the ratio between DDTs and PCBs, it is worth note that values are quite similar for Tai Lake and Pearl River Delta, whereas the ratio showed much more elevated values at Poyang, because of dominance of DDTs over PCBs at this area, indicating a clear predominance of agricultural vs. industrial pollutants.

Comparison with Pakistan and with other regions

This comparison will be based exclusively on egg pollution burdens, since heterogeneity of prey and foraging areas precluded the use of other types of samples.

HCB. These compounds were only detected in samples from China and not in Pakistan. Levels in Little Egret eggs from Chinese areas were quite similar (ca. 3-6 ppb) and very low, as it happened for the other species analyzed, which showed narrow ranges (2-30 ppb). Levels in Little Egrets from the Danube delta were much higher (487 ppb, Aurigi et al. 2000).

HCHs. Only our data and a single value for A. purpurea in Doñana (Alberto and Peña 1981) are available for comparison. In all our areas the Little egret was the species attaining the higher levels of pollution by such compounds. Levels in eggs of that species ranged from 10 ppb at Poyang to 50 ppb at Haleji Lake. In ascending order (from low to high pollution) the areas were: Poyang -> Taunsa –> Pearl River Delta and Tai Lake –> Haleji. Therefore, for such compounds the Poyang lake fits better the condition of low pollution area than their corresponding area in Pakistan (i.e. Haleji lake). The fact that the levels in Little Egret eggs, which feeds mainly in the seepage lagoons around Haleji (Ruiz et al. midterm report), are higher than those found in eggs of E. intermedia from the same locality, which forages mainly inside the lake, agrees well with the fact that only in one sediment sample from Haleji seepage lagoons, the HCHs were also detected. In any case, the levels are very low in general and well below the dangerous exposure to the toxicant (4000 to 37000 ppb ww). This is also the case for all the other species analyzed in the different areas, e.g. E. gularis from Karachi, E. intermedia from Haleji, Bubulcus from Taunsa and Phalacrocorax from Haleji.

Cyclodienes. Since there are only data from our samples, comparison with other areas is precluded.

The lower levels corresponded to the “pristine” areas in both countries, i.e. to the Poyang and Haleji (ND to 1 ppb), intermediate levels in Little Egrets from agriculture and industry polluted areas in China: Pearl River Delta and Tai Lake (ca. 15 ppb), and higher levels in egrets from areas devoted to agriculture (Taunsa) and industrial activities (E.gularis from Karachi) in Pakistan (ca. 30 ppb). However, these levels are far from those reported to have effects in birds, which are in the range of more than 1500 ppb, e.g. for the eggs of the American Kestrel (Falco sparverius) (Henny et al. 1983)

DDTs. Little Egrets from the three areas in China present quite similar levels of these pollutants, but they reach the highest levels in eggs from the supposed pristine area, that is, the Poyang lake, which in this case exhibits levels about fivefold those of their counterpart in Pakistan (Lake Haleji). In fact, only the most DDT polluted area among all those analyzed (Taunsa), showed higher average levels than the Poyang lake. These levels are, however, below those reported for Little Egrets from the Ebro (Ruiz et al. 1991) or the Danube (Aurigi et al. 2000) deltas. Also the levels are higher in the USA, according to data obtained for eggs of E. thula from Texas (Mora 1996) or from San Francisco Bay. However, the levels reported for Little Egrets in Italy by Fasola et al. (1998) are much lower. In any case, the levels reported in this study seem to be well below the ranges showing adverse effects in bird reproduction (Blus 1996), despite that significant eggshell thinning has been detected in one case for E. intermedia of Haleji lake (Sanpera et al. in press).

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PCBs. Excepting E. gularis from Karachi the levels we have found in the different areas and species are low when compared to literature data (see Tab.). Poyang and Haleji fitted well to their condition of pollution-free areas for these compounds (ca. 1-3 ppb), followed by Taunsa (20 ppb), Pearl River Delta (46) and Tai Lake (78). Levels in Tai Lake are similar to Little Egrets from N Italy (Fasola 1998), E. thula and E. tricolor from Texas (Mora 1996) and Night Heron from the Danube (Aurigi et al. 2000).

E. gularis from Karachi showed similar levels to those reported for Little Egrets and E. alba from the Danube (Aurigi et al. 2000), but much lower than in Little Egrets from the Ebro Delta (Ruiz et al. 1991).

The levels reported in this study are much lower than those affecting embryo development or survival and egg hatchability in different bird species, which used to be 5000 ppb ww or higher (Hoffman et al. 1996).

Concluding remarks

In China the Poyang lake area is characterized by lower impact of HCBs, HCHs, Cyclodienes and PCBs. However, the egret eggs of that ecosystem showed the highest average levels of DDTs. Another characteristic of Poyang Lake samples is their heterogeneity, since the percentage of samples containing detectable levels for the different organochlorine families is very variable. This indicates that, even though the ecosystem presented low levels of organochlorines, there are important local sources of pollution, some of them responsible of recent inputs. Such heterogeneity is also responsible for the female effect detected for organochlorine levels in eggs of Poyang, since the different individuals foraging at different places can be exposed to very different levels of pollution, then each female layed eggs containing very different burdens of organochlorines in relation to females using other feeding grounds.

At the Tai Lake area, the pollution is the highest for PCBs, indicating that this area, and not the Pearl river Delta, is the one most affected by industrial pollution. Conversely, the levels of DDTs are somewhat higher in Pearl River Delta. At both localities, the pollutants input seem to be older, much more homogeneous (i.e. generalized) than at Poyang lake, as indicated by the percentage of samples having detectable levels of the different organochlorine families. PCBs and DDTs excepted, these two areas showed rather homogeneous levels of pollutants.

In general the levels found in the different areas included in this study are lower than those reported for other areas of the world (Europe, USA) and below the observed ranges having adverse effects on bird reproduction or survival.

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13.Contamination by organic compounds

in samples from Pakistan

Sanpera Carolina, Ruiz Xavier, Llorente Gustavo, Jover LluisDepartament. de Biologia Animal, Avgda. Diagonal 645, 08028-Barcelona , Spain

Ashiq Muhammad, Umar K. Baloch

Pakistan Agriculture Research Council, P.O. Box 1031, Islamabad 45500, Pakistan

The samples for chemical analysis of contaminants were collected from three study areas:1. Karachi Harbour, studied in 2000, and expected to be subject to considerable urban and industrial

pollution.2. Taunsa Barrage, studied in 2000, expected to be subject to pollution from agriculture.3. Haleji Lake, studied in 1999, expected to be relatively unpolluted.

The egret ecology in these study areas are described in the preceding chapters. This chapter summarizes and discusses the main results about the levels of organochlorine compounds of environmental concern. The rough data are listed in App. D. Further analyses of these results are being devoted to publications in preparation.

The manufacture and the use of organochlorine compounds in developed nations has decreased remarkably during the last three decades, but in some developing countries they are still used in the treatment of agricultural pests and as insecticides for vectors of malaria. In tropical ecosystems the environmental fate of these pollutants is affected by high temperatures and heavy rain, which increase the dispersion rate (Iwata et al. 1994, Kannan et al. 1995). However, few data on organochlorine pollutants in biota from tropical ecosystems have been published and, to our knowledge, no data are available from wetlands in Pakistan.

Although initially sampling in different areas was thought to be directed mainly to the Little Egret , the difficulties found for sampling nests of this species at some localities made that the sampling effort had to be allocated on other ardeidae species. Thus, species analysed included Intermediate Egrets (Egretta intermedia)., the dark morph of the Little Egret (designed by some authors as Western Reef Heron Egretta gularis) , the Cattle Egret (Bubulcus ibis, and the Javanese Cormorant (Phalacrocorax niger)

The organochlorine compounds that were analysed are the same as for China (see the preceding chapter).

Sample preparation and analytical methods

In Tab. 13.1 the samples collected for organochlorine analyses in each of the three areas of study, are indicated. Note that prey sample analysed correspond to composites resulting from the pooling of several prey items, as indicated. Fish prey collected in Haleji Lake correspond to four species, Oreochromis niloticus (21 fish pooled in 2 samples), Puntius phuturio (38 fish pooled in 2 samples), Colisa lalia (10 fish pooled in 3 samples), Glossogobius giuris (n = 6) , and one indeterminate species of crustacean, a caridean shrimp (29 shrimps pooled in 3 samples). Fish collected in the Karachi area corresponded to the species Liza abu.

The sampling procedures, the chemical analytical techniques, and the data treatment were the same as described for China (see the preceding chapter).

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_____________________________________________________________________________________

Tab. 13. 1. Samples obtained for each area in Pakistan during the fieldwork campaigns of 1999 and 2000. In parenthesis: no. of items in the composite samples.

_____________________________________________________________________________________Haleji Lake Taunsa Karachi

Eggs (Nest) Little Egret 8 4Intermediate Egret 22 (20)Little Egret (dark morph) 28 (14)Cattle Egret 10 (9)Javanese Cormorant 4 (1)

Preys Fishes 16 1 (9) 3 (15)Shrimps 2Frogs 1 (10)Mice 1 (5)Coleoptera 1 (ind.)Crickets 1 (20)

Sediments Pond 3Rice field 3Channel 3 6Mud 3Seepage lagoon 10

_____________________________________________________________________________________

Results

Descritive statistics for different pollutants are given in Tab. 13.2 to13.7. Concentrations are expressed in ng/g. Concentration in the eggs is reported on a wet weight basis to allow comparison with other literature data. Prey and sediment levels are given on a dry weight basis.

Hexachlorobenzene (HCB). Levels of this pollutant in the eggs were relatively low (Tab. 13.2), and were similar in the egrets from Haleji and those from Karachi colony of the Little Egret (dark morph). Levels in egrets form Taunsa were much lower. In both, prey and sediments, HCB was only detected in samples from Haleji Lake (Tab. 13.2).

Hexachlorocyclohexanes (HCHs). Levels of HCHs in different samples are provided in Tab. 13.3. HCHs were detected in most of the eggs (Tab. 13.3), but they were almost undetectable in both prey and sediments (Tab. 13.3). The highest mean value for these pollutants was found in the Little Egret from Haleji , although Intermediate Egrets from this area reached the maximum values. In the species from Haleji, β-HCH was the most abundant isomer, whereas in Taunsa and Karachi it was the lindane (γ-HCH).

Cyclodienes. Cyclodiene values for different samples are given in Tab. 13.4. In the samples from Haleji, these compounds were almost absent. Nevertheless, although at low levels they were detected in egg samples from Taunsa and Karachi. Concentration in Egrets from both areas were quite similar, but Cattle Egret from Taunsa had lower levels. Fish samples from Karachi present remarkably high concentrations (Tab. 13.4).

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In Intermediate Egrets from Haleji the most abundant cyclodiene was α-endosulfan. In Taunsa, heptachlor epoxide levels were above the other cyclodienes, whereas in Karachi the most abundant was β-endosulfan.

DDTs. DDT compounds, mainly as pp’DDE, were found in all the egg samples analysed (Tab. 13.5 and 13.6). Mean levels were higher in Little Egrets from Taunsa, followed by the Western Reef Heron from Karachi. Nevertheless, maximum values were found in Intermediate Egrets from Haleji. In prey, these compounds were not detected in all the samples, highest values being found in fish (Tab. 13.5 and 13.6) . Remarkably, no DDTs were detected in sediment samples from Taunsa (Tab. 13.5 and 13.6).

PCBs. With regard to PCBs, the highest values were detected in the eggs from Western Reef Heron from Karachi colony (Tab. 13.7). Egret eggs from Taunsa present concentrations much lower, but above those from Haleji. Prey samples from different localities present PCB concentrations which are quite similar (Tab. 13.7). In sediments, the higher values were recorded in the Karachi area. No PCBs were found in sediments from Haleji Lake (Tab. 13.7).

In Tab. 13.8, descriptive statistics for the different groups of pollutants (non-DDT pesticides, sum of pesticides, sum of organochlorines and different pollutant ratios by area and species, are given.

Comparison between species from the same area. Statistical comparisons between species from the same areas have been carried out for Little and Intermediate Egrets from Haleji Lake (Fig. 13.1) and the only significant difference detected was in the HCHs levels, for which the Little Egret showed higher concentrations (Mann-Whitney U=13, p= 0.013).

In Taunsa, significant differences between Little and Cattle Egret were found in both, DDTs (U= 3, p= 0,01) and PCBs (U= 5, p= 0,0365), no significant differences were found for the other pollutants (Fig. 13.2).

Comparison between the three areas. To compare different areas, only Egretta species were considered. In Fig. 13.3 to13.7, boxplots (plotting the median, interquartile range and range excluding outliers) of different pollutants in eggs from the study areas are depicted. Significant differences were found for HCB levels (Kruskall-Wallis: Χ2= 17.062, p< 0.001), DDTs (Kruskall-Wallis: Χ2= 13,580, p=0.001), PCBs (Kruskall-Wallis: Χ2= 27,450, p< 0.001), and also in the ratio ppDDE/Sum of DDTs (Kruskall-Wallis: Χ2= 20,716, p< 0.001) and in the ratio DDTs/PCBs (Kruskall-Wallis: Χ2= 25,248, p< 0.001) (Figs. 13.8 and 13.9).

Female effect. In the colony of Western Reef Heron from Karachi, in which two eggs were sampled in each nest the result of the ANOVA showed that there is a female effect on PCBs concentration in the eggs (F= 3.813, p= 0.009) as well as on the final levels of organochlorine pollutants (F= 3.037, p= 0.024).

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_____________________________________________________________________________________Tab. 13.2. Concentrations of hexachlorobenzene HCB (ng/g) in the samples. The values are: number of

samples, percentage of samples with contaminants above detection limit, geometric mean concentration of the contaminants, minimum an maximum values. All values are expressed as ppb, or ng/g on a dry weight

basis, but for eggs the values are expressed on a wet weight basis (w.w.) as well.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsHaleji Lake Little Egret 8 ( 6) 75 3.4 2.4-4.8

Iintermediate Egret 20 (16) 80 3.7 2.2-4.6Javanese Cormorant 1 (1) 100 2.9 2.7-3.1

Taunsa Little Egret 4 ( 2) 50 0.5 0.4-.6Cattle Egret 9 ( 4) 44 0.6 0.4-0.9

Karachi Little Egret (dark morph)14 (13) 93 2.1 1.1-6.8

PreyHaleji Lake Fishes 16 (14) 88 11.5 1.8-59.7

Shrimps 2 ( 2) 100 5.7 5.6-5.7

Taunsa Fishes 1 ( 0) 0Frogs 1 ( 0) 0Mice 1 ( 0) 0Coleoptera 1 ( 0) 0Crickets 1 ( 0) 0

Karachi Fishes 3 ( 0) 0

SedimentHaleji Lake Seepage lagoon 10 ( 6) 60 1.1 0.4-1.7

Taunsa Pond 3 ( 0) 0Rice field 3 ( 0) 0Channel 3 ( 0) 0

Karachi Channel 6 ( 0) 0Mud 3 ( 0) 0

_____________________________________________________________________________________

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_____________________________________________________________________________________Tab. 13.3. Concentrations (ng/g) of hexachlorocyclohexane compounds (HCHs) in the samples. Values as

in Tab. 13.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

Eggs

Haleji Lake Little Egret 8 ( 6) 75 49.9 16.2-147.9Intermediate Egret 20 (16) 80 7.7 0.2-1377.4

Javanese Cormorant 1 (1) 100 2.0 1.6-2.2

Taunsa Little Egret 4 ( 4) 100 17.6 4.4-39.9Cattle Egret 9 ( 8) 89 4.8 2.1-37.6

Karachi Little Egret (dark morph) 14 (14) 100 9.1 3.3-91.5

PreyHaleji Lake Fishes 16 ( 0) 0

Shrimps 2 ( 0) 0

Taunsa Fishes 1 ( 0) 0Frogs 1 ( 0) 0Mice 1 ( 0) 0 2Coleoptera 1 ( 0) 0Crickets 1 ( 1) 100 2.8 2.8-2.8

Karachi Fishes 3 ( 0) 0

SedimentsHaleji Lake Seepage lagoon 10 ( 1) 10.0 1.0 1.0- 1.0

Taunsa Pond 3 ( 0) 0Ricefield 3 ( 0) 0Channel 3 ( 0) 0

Karachi Channel 6 ( 0) 0Mud 3 ( 0) 0

_____________________________________________________________________________________

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_____________________________________________________________________________________

Tab. 13.4. Concentrations of cyclodiene insecticides (ng/g) in the samples. . Values as in Tab. 13.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsHaleji Lake Little Egret 8 ( 0) 0

Intermediate Egret 20 ( 2) 10.0 1.6 0.7-3.6Javanese cormorant 1 ( 0) 0

Taunsa Little Egret 4 ( 4) 100 26.7 7.8-151.0Cattle Egret 9 ( 8) 89 9.5 1.4-49.4

Karachi Little Egret (dark morph) 14 (14) 100 33.0 12.1-98.1

PreyHaleji Lake Fishes 16 ( 3) 19 3.9 0.7-10.5

Shrimps 2 ( 0) 0

Taunsa Fishes 1 ( 0) 0Frogs 1 ( 1) 100 61.9 61.9-61.9Mice 1 ( 0) 0Coleoptera 1 ( 1) 100 10.6 10.6-10.6Crickets 1 ( 1) 100 12.6 12.6-12.6

Karachi Fishes 3 ( 3) 100 227.7 146.2-349.5

SedimentsHaleji Lake Seepage lagoon 10 ( 0) 0

Taunsa Pond 3 ( 3) 100 7.0 0.7-67.7Ricefield 3 ( 2) 67 7.8 5.9-10.3Channel 3 ( 1) 33 1.3 1.3-1.3

Karachi Channel 6 ( 1) 17 1.4 1.4-1.4Mud 3 ( 2) 67 1.2 1.1-1.3

_____________________________________________________________________________________

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_____________________________________________________________________________________

Tab. 13.5. Concentrations of DDTs (sum) (ng/g) in the samples. Values as in Tab. 13.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsHaleji Lake Little Egret 8 ( 8) 100 134.6 39.1-1884.7

Intermediate Egret 20 (20) 100 173.3 33.5-20982.9Javanese Cormorant 1 (1) 100 31.7 20.9-38.9

Taunsa Little Egret 4 ( 4) 100 607.0 164.3-4202.5Cattle Egret 9 ( 9) 100 68.7 25.4-2957.5

Karachi Little Egret (dark morph) 14 (14) 100 541.6 361.4-1064.6

PreyHaleji Lake Fishes 16 ( 9) 56 23.6 7.6-149.3

Shrimps 2 ( 1) 50 16.6 16.6-16.6

Taunsa Fishes 1 ( 1) 100 78.4 78.4-78.4Frogs 1 ( 1) 100 8.4 8.4-8.4Mice 1 ( 0) 0Coleoptera 1 ( 0) 0Crickets 1 ( 0) 0

Karachi Fishes 3 ( 3) 100 32.1 29.6-34.4

SedimentsHaleji Lake Seepage lagoon 10 ( 3) 30 7.0 1.4-22.2

Taunsa Pond 3 ( 0) 0Ricefield 3 ( 0) 0Channel 3 ( 0) 0

Karachi Channel 6 ( 3) 50 2.3 0.4-7.5Mud 3 ( 3) 100 26.8 5.7-127.4

_____________________________________________________________________________________

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_____________________________________________________________________________________Tab. 13.6. Concentrations of DDE (ng/g) in the samples. Values as in Tab. 13.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsHaleji Lake Little Egret 8 ( 8) 100 133.9 39.1-1884.7

Intermediate Egret 20 (20) 100 166.5 29.6-20846.6Javanese Cormorant 1 (1) 100 30.8 20.9-37.3

Taunsa Little Egret 4 ( 4) 100 526.4 161.0-3169.3Cattle Egret 9 ( 9) 100 66.9 25.4-2329.7

Karachi Little Egret (dark morph) 14 (14) 100 477.7 319.2-983.7

PreyHaleji Lake Fishes 16 ( 9) 56 13.8 2.0-149.3

Shrimps 2 ( 0) 0

Taunsa Fishes 1 ( 1) 100 69.3 69.3-69.3Frogs 1 ( 1) 100 8.4 8.4-8.4Mice 1 ( 0) 0Coleoptera 1 ( 0) 0Crickets 1 ( 0) 0

Karachi Fishes 3 ( 3) 100 10.1 9.3-11.1

SedimentsHaleji Lake Seepage lagoon 10 ( 3) 30 5.1 1.4-10.3

Taunsa Pond 3 ( 0) 0Ricefield 3 ( 0) 0Channel 3 ( 0) 0

Karachi Channel 6 ( 3) 50 0.9 0.4-2.0Mud 3 ( 3) 100 5.8 1.3-22.7

_____________________________________________________________________________________

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_____________________________________________________________________________________

Tab. 13.7. Concentrations of PCBs (sum) (ng/g) in the samples. Values as in Tab. 13.2.

_____________________________________________________________________________________no.samples %contaminated mean min-max

EggsHaleji Lake Little Egret 8 ( 3) 38 1.6 0.9-4.6

Intermediate Egret 20 (15) 75 2.5 1.0-54.6Javanese Cormorant 1 (1) 100 2.6 1.9-3.5

Taunsa Little Egret 4 ( 4) 100 20.7 7.3-131.9Cattle Egret 9 ( 8) 89 5.3 1.2-258.0

Karachi Little Egret (dark morph) 14 (14) 100 853.8 492.1-1677.1

PreyHaleji Lake Fishes 16 ( 2) 13 2.9 1.5-5.7

Shrimps 2 ( 1) 50 10.6 10.6-10.6

Taunsa Fishes 1 ( 1) 100 7.4 7.4-7.4Frogs 1 ( 1) 100 6.5 6.5-6.5Mice 1 ( 1) 100 6.0 6.0-6.0Coleoptera 1 ( 1) 100 9.0 9.0-9.0Crickets 1 ( 1) 100 6.8 6.8-6.8

Karachi Fishes 3 ( 3) 100 5.8 4.5-6.6

SedimentsHaleji Lake Seepage lagoon 10 ( 0) 0

Taunsa Pond 3 ( 3) 100 0.6 0.5-.0.9Ricefield 3 ( 1) 33 0.5 0.5-.0.5Channel 3 ( 3) 100 0.6 0.3-0.8

Karachi Channel 6 ( 4) 67 0.8 0.5-1.9Mud 3 ( 2) 67 16.6 4.3-63.4

_____________________________________________________________________________________

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_____________________________________________________________________________________

Tab. 13.8 . Mean concentration (ng/g w.w.) of different organochlorines and ratios among different pollutants in the eggs.

_____________________________________________________________________________________

Haleji Lake Taunsa Karachi_____________________________ ______________ __________Little Intermediate Javanese Little Cattle Little EgretEgret Egret Cormorant Egret Egret (dark morph)

N (detec) 8( 7) 20(19) 1(1) 4( 4) 9( 8) 14(14) % detected 88 95 100 100 89 100Mean ΣPEST (noDDTs) 37.5 11.7 4.9 48.9 16.5 47.7Min 4.55 .22 4.66 12.22 6.94 21.34Max 152.02 1377.43 5.10 174.81 87.83 183.24

N (detec) 8( 8) 20(20) 1(1) 4( 4) 9( 9) 14(14)% detected 100 100 100 100 100 100Mean ΣPEST 202.1 187.9 34.8 670.5 85.2 597.3Min 43.66 33.50 20.87 206.94 27.80 386.25Max 1934.55 22360.30 43.98 4377.25 3045.31 1119.26

N (detec) 8( 8) 20(20) 1(1) 4( 4) 9( 9) 14(14)% detected 100 100 100 100 100 100Mean ΣOCs 205.1 195.4 35.9 693.8 90.1 1462.3min 48.21 38.54 20.87 220.58 27.80 950.02max 1934.55 22360.30 43.98 4509.12 3303.33 2788.46

N (detec) 8( 8) 20(20) 1(1) 4( 4) 9( 9) 14(14)% detected 100 100 100 100 100 100

Mean ppDDE/DDTs .99 .96 .97 .87 .98 .88min .957 .827 .932 .754 .788 .763max 1.000 1.000 1.000 .980 1.000 .959

N (detec) 8( 8) 20(20) 1(1) 4( 4) 9( 9) 14(14)% detected 100 100 100 100 100 100

Mean DDTs/ΣPEST .72 .92 .91 .91 .81 .91min .277 .659 .877 .794 .668 .802max 1.000 1.000 1.000 .960 1.000 .951

N (detec) 8( 3) 20(15) 1(1) 4( 4) 9( 8) 14(14)% detected 38 75 100 100 89 100Mean DDTs/PCBs 40.5 117.5 14.4 33.3 16.9 .65min 8.591 3.069 10.045 12.042 5.317 .350max 67.600 519.300 18.818 53.045 30.013 .909

_____________________________________________________________________________________

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Fig. 13.1. Boxplot of pesticides and organochlorines in Little Egret and Intermediate Egrets from Haleji Lake.

Fig. 13.2. Boxplot of pesticides and organochlorines in Little Egret and Cattle Egrets from Taunsa.

94 94 84N =

Bubulcus ibisEgretta garzetta

5000

4000

3000

2000

1000

0

SUM PEST (no DDTs)

(ng/g)

SUM PEST

(ng/g)

SUM OCs

(ng/g)

198 198 187N =

Egretta intermediaEgretta garzetta

3000

2000

1000

0

SUM PEST (no DDTs)

(ng/g)

SUM PEST

(ng/g)

SUM OCs

(ng/g)

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Fig. 13.3. Boxplot of HCB (ng/g) in egrets from the three areas under study.

Fig. 13.4. Boxplot of HCHs (ng/g) in egrets from the three areas under study.

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Fig. 13.5. Boxplot of ΣCyclodiene Insecticides (ng/g) in egrets from the three areas under study.

Fig. 13.6. Boxplot of ΣDDTs (ng/g) in egrets from the three areas under study.

114

Fig. 13.7. Boxplot of PCBs (ng/g) in egrets from the three areas under study.

Fig. 13.8. Boxplot of the ratio DDTs/PCBs in egrets from the three areas under study.

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Fig. 13.9. Boxplot of several pesticides (ΣPEST excluding DDTs, ΣPEST, ΣOCs) in egrets from the three areas under study.

Fig. 13.10. Boxplot of several ratios (ppDDE/DDTs and DDTs/ΣPEST) in egrets from the three areas under study.

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Discussion

There is no information about the levels or the impact of persistent organic pollutants in the biota from different wetlands in Pakistan, because, as far as we know, no previous works evaluating pollution in organisms have been published. The present use of pesticides in Pakistan is concentrated on cotton fields, which production is concentrated mainly in the Punjab and in the Sindh provinces, and to a lesser extent in the Baluschistan. The pesticides applied are mostly insecticides against a number of pest species, e.g. white fly, jassid, aphid and bollworms. Pesticides are also being used in other crops, such as vegetables and fruit . Estimated figures on consumption of pesticides in Pakistan ranged from: 13,030 metric tons estimated for 1990-91 to 30,471 metric tons in 1995-96 (source: STAT-USA on the internet, US Department of Commerce). The results presented here constitute a first approximation to evaluate impact of several organochlorine pollutants using wading birds as indicators.

In order to compare data gathered in the present work, organochlorine concentrations on the same or related species from other areas have been used. In Tab. 13.9 information on organochlorines in eggs from Ardeidae species from several localities have been compiled.

Haleji Lake. The two egret species sampled at Haleji Lake, the Little and the Intermediate egrets, present few differences between them with regard to the levels of different pollutants (Tab. 13.10).

In both species, DDTs are the pollutants which attain the higher concentrations in eggs. The distribution of these compounds in the area is thought to be wide, since they had been found in all the egg samples, thus pointing to the ubiquity of DDTs in the Lake and in the egret’s foraging areas. Among DDTs, pp’-DDE was the main isomer corresponding to the 99% of total DDTs in Little Egrets and 96% in Intermediate Egrets. DDE concentrations in Egrets from Haleji were lower than reported elsewhere for eggs of large herons, such as Great Blue Heron (Fitzner et al. 1988, Custer et al. 1997, 1998) , its values being the same order of magnitude to those reported for other medium sized herons from the Mediterranean basin (Ruiz et al. 1991, Fasola et al. 1998) and the United States (Mora, 1996, Rodgers 1997). Mean DDE levels found in the eggs are much lower than levels reported by Blus et al. (1980) as having biological effects on birds (< 2 mg/Kg ww) or by Custer et al. (1997) to impair avian reproduction in herons (10 mg/kg ww). Nevertheless, the concentration in three eggs of Intermediate Egret were above these levels (2.27, 11.93 and 29.76 μg/g ww) and thus, some birds are exposed to high DDTs levels, probably while feeding in agricultural areas or paddy fields. The two eggs with the higher levels belong to the same nest and reflect an outstanding effect of the breeding female on the egg pollutant burdens, as has been described previously by Pastor et al. (1995). We have also measured the eggshell thickness in these eggs and we found them to be thinner than the other eggshells collected (Mann-Whitney U= 3.00, p= 0.013). Eggshell thinning has been recognized as one of the main causes of reproductive failure in bird populations (Blus et al. 1980, Furness 1993, Blus 1996).

DDE was also the main metabolite present in sediment samples. The high DDE/DDTs ratio in the eggs suggest that exposure to DDTs has not been recent, indicating that DDT has been metabolised by the bird or that DDT is mainly consumed as DDE.

Other organochlorines analysed in the eggs, as HCHs, HCB and PCBs follow in abundance to DDTs, but their concentrations are low. Available data on HCH usage indicates a lower consumption of these pesticides in Pakistan compared to neighbouring countries like India or China ( Kannan et al. 1992, Iwata et al. 1994, Li et al. 1998), although long-range atmospheric transport could occur. The fact that no HCH was detected in fish or sediment samples is in agreement with the findings of several authors (Iwata et al. 1994, Kannan et al, 1995) who reported a low accumulation of HCHs in aquatic organisms and sediments pointing to the high temperatures of the tropics, and its higher solubility as the cause for the low levels of semi-volatile contaminants in these compartments. Pastor et al. (1996), when studied transfer of organic pollutants between different egg compartments in the Audouin’s gull (Larus audouinii ) found that HCHs transfer from yolk sacs to embryos was lower than for other organic pollutants because of its higher polarity.

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The low levels of PCBs in the eggs of egrets from Haleji and the absence of these compounds in the fish or sediment samples are indicators of the low industrial activity around the area, also suggesting that most of the egrets are sedentary.

Sampling for the Javanese Cormorant was conducted on an opportunistic basis, and four eggs corresponding to one whole nest were taken. All the pollutants analysed showed low concentrations, under levels reported for other Phalacrocorax species from elsewhere (Custer et al. 1997, Custer et al. 1999, Aurigi et al. 2000). In relation to Egrets from Haleji, the levels in cormorants are also remarkably low. This might be due to the fact that cormorants forage on the lake bottom. Since Haleji is surrounded by a stony desert, the main source of pollutants should be the atmospheric deposition. Therefore, most of them should be retained by the huge amount of aquatic plants present on the lake surface, thus never reaching the bottom of the lake and making bioavailavility of these compounds lower for benthonic animals on which cormorants prey. Anyway, this hypothesis will remain untested until specific work addressed to elucidate it is undertaken.

Taunsa. In the eggs of the two species sampled in this area (Little and Cattle Egrets) the higher organochlorine levels corresponded to DDTs mainly DDE (87% in Little Egret and 98% in Cattle Egret). These compounds were found in all the egg samples, thus indicating a wide distribution pattern. The two species present differences, as the levels in the eggs of Little Egrets were eight times higher than in the Cattle Egrets.

The DDE concentrations reported for eggs of Little Egrets from other localities show great variation, probably related to local conditions, although Custer (2000) states that they are usually low?. Fasola et al. (1998) found low DDE levels in egrets from N Italy, but Aurigi et al. (2000) found very high DDTs levels in the same species inhabiting the Danube Delta. The results obtained by Ruiz et al. (1991) in the Ebro Delta (Spain) for the same two species considered here show the opposite trend to what we have observed, since levels in the Cattle Egret were ten times higher than those of the Little Egret. Possible reasons to explain this difference remain unclear. Nevertheless, DDT levels in both egrets are in agreement with observations made in their prey items. In fact, DDE is present in aquatic preys both, in fish and frogs collected in Taunsa, but not in the insects sampled in the terrestrial media. Thus, observed differences between both species should be related to their feeding habits since, while Little Egrets feed markedly on fish, the Cattle Egrets show a feeding behaviour more dependent on terrestrial preys, including insects (Cramp and Simmons 1977).

Among other factors which could contribute to the observed results, it should be considered the possibility that in the terrestrial media DDTs remain immobilized in the soil during the drought period and thus, they are unavailable to the insects during this period. Contrarily, in the aquatic environment dynamics of the contaminant would be subjected to partition equilibrium dynamics between sediment and water, which could explain in part their presence in the aquatic biota. Alternatively it should be considered that Egrets at Taunsa can move to other places to forage, or that the egrets are partially migratory birds at this locality.

A similar problem was encountered with the other pollutants analysed. In the eggs cyclodiene compounds were the second organochlorine pollutants in importance, followed by PCBs and HCHs. In all the cases a marked difference exists between the two species, Little Egrets reaching always the higher concentrations. It must be stressed that the results in prey and sediments deserve further study, as there is not a clear agreement between pollutant levels in these samples and those in the eggs. The levels of PCBs in the eggs are generally low compared to data reported in the literature (see Tab. 13.9) and doesn’t represent a risk for the bird populations inhabiting this area.

Karachi. The Western Reef Heron sampled in the Karachi area, presents high levels of several organochlorine pollutants, particularly PCBs and DDTs.

The concentration of DDT compounds in the eggs was high (GM= 542 ng/g ww), 88% of them corresponding to DDE. Nevertheless, it must be pointed out that variability is relatively small (min: 361, max: 1064) and thus, none of the samples present concentrations above levels associated to risk (>2 μg/g ww, Blus et al. 1980). These compounds were detected also in the fish which constitute its prey, but DDE percentage is then much lower, about one third, the rest corresponds mainly to pp’-DDD. Within the

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sediments, mud has a much higher concentration compared to samples collected in the channel and in that, only a fraction about 20- 40% was pp’-DDE, most of the compound being present as pp’-DDD. This metabolite is formed in the soil owing to anaerobic bacteria (Matsumura 1975).

The PCBs are the organochlorines reaching the highest levels in this area. Their maximum concentrations are found in the eggs (GM= 854 ng/g ww), and in lower quantities, they have been detected also in prey and sediments. Egg concentrations are similar to those reported by Aurigi (2000) for Little Egrets from the Danube Delta. These pollutants were detected in all the eggs and prey samples, pointing to a wide distribution of PCBs in the Karachi area, probably related to discharging of untreated sewage waters, both from industrial and domestic origin. The sensibility of birds to PCBs and their effects on bird reproduction are highly variable between species, levels as low as 100 ng/g ww in the eggs from chickens have been reported to decrease gluconeogenic enzyme activity in experimental conditions (Srebocan et al. 1977, reported by Hoffman et al. 1996). Nevertheless, the levels of PCBs in Western Reef Heron eggs are lower than the levels reported by Hoffman et al. (1996) to cause effects in other bird species in the field.

Both pollutants, DDTs and PCBs, as well as the sum of organochlorines, present a marked effect of the female, that is, variability between eggs from the same nest (within component) is significantly lower than between eggs from different nests (between component), indicating that just one egg per nest is enough to evaluate the pollution level by these compounds.

The levels of cyclodiene insecticides are also moderately high, β-endosulfan being the main compound involved in the egg’s pollution burden. These compounds have been identified in every egg and in all the prey samples, but nothing could be said about, as their effects in birds and eggs remain largely unknown (Wiemeyer, 1996).

Comparison between areas. Overall, the results show that Egret eggs reflect well the differences in expected exposure to the different pollutants according to which the areas were choosen. Thus, Haleji Lake, elected as the “pristine” area in Pakistan, showed significantly lower concentrations in average for Cyclodienes, DDTs and PCBs than the other two areas, while Taunsa is characterized by a combination of larger concentrations of Cyclodienes and DDTs with relatively low levels of PCBs, and the Karachi harbour by relatively large concentrations of Cyclodienes, DDTs and very high concentartions of PCBs, being the only area where such industrial organochlorines reach higher levels than the pesticide compounds.

In contrast, the HCB levels, being very low in general, are significantly larger at Haleji and smaller at Taunsa than at Karachi Harbour. The fact that only at Haleji, the sediments and prey presented detectable levels of that compound, reveals that more or less recent inputs of such compound have taken place at this site. HCB is used for fungicidal seed treatments, therefore, perhaps local population living around the lake has used this compound to preserve seeds or foodstuff.

The average DDTs levels were higher in the eggs from Little Egrets collected at Taunsa and in Western Reef Heron from Karachi colony, than in the Intermediate Egrets from Haleji. It must be taken into account that Taunsa is an area mainly devoted to agriculture which probably received in the past high inputs of pesticides and among them, DDTs. On the other hand, Karachi is at the tail-end of the surface water supplies from the Indus. The city receives water which has been used for municipal, agricultural, and industrial purposes, often several times. Moreover, none of the cities along the Indus River treat the water before discharging it in the river (Rahman et al. 1997), thus agricultural pesticides are expected to arrive through water supply and subsequent domestic sewage. The lack of farming activities around Haleji would result in lower levels of pesticides reaching these waters, so, atmospheric transport would account for most of the DDT presence in the area. Also, it must be pointed out that practically all DDT residues in Haleji corresponded to pp’-DDE,

With regard to HCHs, no differences were found between different areas, and even higher concentrations were attained by egret eggs from Haleji Lake. Carey et al. (1998, and references herein) stated that about 99,6% of HCHs applied to paddy fields in tropical agrosystems are volatilized to the atmosphere and estimated than only 0,1% of the applied HCH was ultimately drained to the sea by the river. Kannan et al.

(1995) report that in spite of the recent use of HCH in some southeast Asian countries, as India, the residue levels in fish are low, because of the rapid volatilisation of HCH isomers in tropical latitudes.

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___________________________________________________________________________________________Tab. 13.9. Levels of DDTs and PCBs in herons and egrets from different regions (literature data)

___________________________________________________________________________________________N PP-DDE PP-DDD DDTs PCBs Source

Ardea alba Everglades. FL 6 80 40 <0.05 Rodgers1997Ardea alba Lake Kissimee. FL 5 <0.05 <0.05 Rodgers 1997Ardea cinerea Danube Delta 2 1285.2 283 Aurigi et al. 2000Ardea herodias LLMadre.TX 10 735 396 Mora 1996Ardea herodias British Colum.CAN 47 85 - 549 418 - 1220 Elliott et al. 1989Ardea herodias Wa. USA 30 35 - 2220 139 - 15580 Speich et al. 1992Ardea herodias Columbia.USA 38 3120 - 4710 nd - 490 1560 - 2240 Fitzner et al. 1988Ardea herodias Marshes. USA 19 440 - 3610 nd - 1000 360 - 3340 Fitzner et al. 1988Ardea herodias Puget. USA 3 1470 nd 3350 Fitzner et al. 1988Ardea herodias Mississipi. USA 50 1310 14.9 3040 Custer et al. 1997Ardea herodias Indiana. USA 10 1580 30 4900 Custer et al. 1998Ardea herodias Oak Ridge 100 -240 Halbrook et al.1999Ardea purpurea Ebro. Spain ? 1300 1400 3200 Ruiz et al. 1991Ardea purpurea Doñana. Spain 3 2372 1704 Alberto & Peña 1981Ardeola ralloides Ebro. Spain ? 200 200 500 Ruiz et al. 1991Ardeola ralloides Macedonia. GR 20 3.8 nd Albanis et al. 1996Cattle Egret Ebro D. Spain ? 2600 2800 3300 Ruiz et al. 1991Cattle Egret Taunsa 10 66.9 68.7 5.3 Present studyEgretta alba Danube Delta 1 4764.5 785.8 Aurigi et al. 2000Egretta caerulea Everglades. FL 6 340 <0.05 <0.05 Rodgers 1997Egretta caerulea Lake Kissimee. FL 4 <0.05 <0.05 <0.05 Rodgers1997Little Egret Italy 22 30 39 77 Fasola et al. 1998Little Egret Ebro. Spain ? 600 800 2700 Ruiz et al. 1991Little Egret Haleji 8 133.9 134.6 1.6 Present studyLittle Egret Taunsa 4 526.4 607.0 20.7 Present studyLittle Egret PoyangHu, China 38 545.28 547.83 3.71 Present studyLittle Egret TaiHu, China 36 408.41 426.06 78.97 Present studyLittle Egret Shunde EP, China 20 448.38 475.09 46.48 Present studyLittle Egret Danube Delta 3 16939.7 764.59 Aurigi et al. 2000Little Egret (dark) Karachi 28 477.7 541.6 853.77 Present studyIntermediate Egret Haleji 22 166.5 173.3 2.53 Present studyEgretta thula LLMadre.TX 4 249 78 Mora 1996Egretta thula SFrancisco 50 824-3010 nd-246 185 - 5380 Hothem et al. 1995Egretta tricolor LLMadre.TX 4 56 67 Mora 1996Night Heron TaiHu, China 3 4402.63 4497.42 96.15 Present studyNight Heron Italy 7 14 41 4 Fasola et al. 1998Night Heron Italy 20 82 90 Fasola et al. 1987Night Heron Sfrancisco Bay 1591 466 - 5970 nd -25 603-4130 Hothem et al. 1995Night Heron Green B. Wi 1? 2200 30 11000 Custer&Custer 1995Night Heron Or/Wa. USA 14 400-4600 nd - 50 r: nd - 610 Blus et al. 1997Night Heron Danube Delta 1 850.6 93.1 Aurigi et al. 20009Phalacrocorax auritus Green B. Wi 3900 13600 Custer et al. 1999Phalacrocorax auritus Green B. Wi 2220 13000 Custer et al. 1997Phalacrocorax carbo Danube Delta 10 4340.01 527.6 Aurigi et al.2000Javanese Cormorant Haleji 4 30.8 31.7 2.6 Present studyPhalacrocorax pygmaeus Danube Delta 4 3645.99 897.85 Aurigi et al. 2000

___________________________________________________________________________________________

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_______________________________________________

Tab. 13.10 (ng/g)

_______________________________________________Little Egret Intermediate Egret

DDE 134 166DDTs 135 173HCHs 50 8HCB 3.44 3.66Cyclodienes nd 1.6PCBs 1.62 2.53

_______________________________________________

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14.Conclusions

TO BE EXPANDED

Contamination data show that concentration levels are generally lower than the threshold known to harm wildlife, both for metals and other elements, and for organic compounds, with some exceptions. These results are mostly welcomed, in that they testify a reduced environmental contamination.

122

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Appendix A. List of samples collected in China (from Guandong in 2000, Poyang lake 1999, Wuxi 2000), and their content of metals and other elements (ppm, on dry weight of the sample, nd: not detected, empty cells mean elements not analysed for that sample).

______________________________________________________________________________________________________________________________________________________________________________________________________________________________Ordi Study Material Type Species Code Cad Mercu Lead Chro Cop Iron Manga Arse Sil Bro Co Ce Lantha Nic Scan Sele Zincnal area of mium ry mium per nese nic ver mine balt sium num kel dium niumno. theof samplethesample

1 Pearl River Egg albumen Little Eg. 02_22 Pearl River Egg albumen Little Eg. 03_13 Pearl River Egg albumen Little Eg. 320_24 Pearl River Egg albumen Little Eg. 322_25 Pearl River Egg albumen Little Eg. 97_26 Pearl River Egg Little Eg. 6 nd nd 209,300 0,173 55,100 0,352 0,035 nd nd 0,000 4,127 162,0007 Pearl River Egg Little Eg. 20 nd nd 79,950 nd 54,400 0,076 0,027 nd nd 0,002 4,747 31,8008 Pearl River Egg Little Eg. 27 nd nd 130,000 0,156 nd 13,500 0,052 0,020 0,059 nd 0,016 3,080 2,6609 Pearl River Egg Little Eg. 02_1-ct nd nd 73,900 0,163 nd 20,870 nd 0,034 0,226 nd 0,005 1,997 37,40010 Pearl River Egg Little Eg. 03_1 nd nd 91,450 0,602 28,900 0,010 0,033 0,313 nd 0,001 2,620 nd11 Pearl River Egg Little Eg. 18_1 nd 0,352 0,049 nd nd 128,130 nd 74,700 0,078 0,027 0,105 nd 0,000 3,073 14,90012 Pearl River Egg Little Eg. 18_2 nd 0,282 0,04413 Pearl River Egg Little Eg. 220_114 Pearl River Egg Little Eg. 220_215 Pearl River Egg Little Eg. 314_1 nd nd 131,500 0,327 51,270 0,154 0,050 0,264 nd 0,001 3,587 91,10016 Pearl River Egg Little Eg. 314_217 Pearl River Egg Little Eg. 318_1 nd nd 312,000 0,452 nd 67,700 0,222 0,086 nd nd 0,063 5,170 0,49918 Pearl River Egg Little Eg. 318_219 Pearl River Egg Little Eg. 320_1 nd 1400,000 119,550 0,814 nd 50,700 nd 0,012 nd nd 0,001 4,197 54,30020 Pearl River Egg Little Eg. 321_1 nd nd 129,750 0,828 22,400 0,035 0,011 nd nd 0,001 4,690 nd21 Pearl River Egg Little Eg. 321_222 Pearl River Egg Little Eg. 322_123 Pearl River Egg Little Eg. 323_1 nd nd 67,900 0,312 0,846 9,660 nd 0,075 nd nd 0,007 4,007 18,50024 Pearl River Egg Little Eg. 323_225 Pearl River Egg Little Eg. 35_1 nd 105,000 nd nd 95,667 nd 0,168 0,171 nd 0,002 5,953 nd26 Pearl River Egg Little Eg. 35_227 Pearl River Egg Little Eg. 53_1 nd 53,300 0,427 nd 47,400 nd 0,033 0,158 0,002 2,083 35,60028 Pearl River Egg Little Eg. 53_229 Pearl River Egg Little Eg. 59_1 nd 232,300 0,361 0,361 40,800 nd 0,066 0,365 nd 0,002 2,487 nd30 Pearl River Egg Little Eg. 59_231 Pearl River Egg Little Eg. 68_1 nd nd 114,300 nd nd 64,000 nd 0,051 0,171 nd 0,000 4,587 20,20032 Pearl River Egg Little Eg. 68_233 Pearl River Egg Little Eg. 97_1 nd nd 68,050 0,345 82,400 0,077 0,030 nd nd 0,001 2,790 nd34 Pearl River Egg yolk Little Eg. 02_235 Pearl River Egg yolk Little Eg. 03_236 Pearl River Egg yolk Little Eg. 320_237 Pearl River Egg yolk Little Eg. 322_2 nd 274,000 nd nd 25,900 0,598 0,004 nd nd 0,007 4,040 556,00038 Pearl River Egg yolk Little Eg. 97_239 Pearl River Feathers Little Eg. 240 Pearl River Feathers Little Eg. 341 Pearl River Feathers Little Eg. 442 Pearl River Feathers Little Eg. 6

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43 Pearl River Feathers Little Eg. 744 Pearl River Feathers Little Eg. 845 Pearl River Feathers Little Eg. 18 nd nd 150,000 nd nd 138,000 7,590 0,424 nd nd nd 41,100 nd46 Pearl River Feathers Little Eg. 2047 Pearl River Feathers Little Eg. 27 nd nd 385,000 1,230 nd 85,000 3,930 0,259 nd nd nd 13,500 nd48 Pearl River Feathers Little Eg. 35 nd nd 38,100 1,260 nd 55,600 2,470 0,045 nd nd nd nd nd49 Pearl River Feathers Little Eg. 53 nd nd 350,000 0,773 nd 62,200 5,200 0,228 nd nd 0,120 1,580 817,00050 Pearl River Feathers Little Eg. 59 12,500 nd 1090,000 nd nd 42,700 5,530 0,257 1,440 nd 0,106 4,890 1030,00051 Pearl River Feathers Little Eg. 68 9,950 nd 575,000 nd 56,000 10,800 0,087 0,873 nd 0,035 2,800 38,20052 Pearl River Feathers Little Eg. 97 15,700 nd 1553,000 1,290 71,000 6,870 0,061 0,441 53,300 0,019 3,500 983,00053 Pearl River222 Feathers Little Eg. 220 nd nd 780,000 1,320 2,650 112,000 8,130 0,046 0,642 nd 0,090 1,690 4,39054 Pearl River Feathers Little Eg. 314 nd nd 752,000 4,520 9,110 102,000 5,960 0,252 nd nd 0,111 nd 28,50055 Pearl River Feathers Little Eg. 318 nd nd 236,000 1,670 74,500 12,200 0,254 1,800 nd 0,102 nd nd56 Pearl River Feathers Little Eg. 320 29,400 nd 1120,000 2,820 77,500 7,790 0,135 0,545 74,300 0,105 2,580 131,00057 Pearl River Feathers Little Eg. 321 14,000 nd 736,000 nd 64,600 6,050 0,274 nd nd 0,049 5,370 nd58 Pearl River Feathers Little Eg. 322 nd nd 37,100 nd nd 91,700 9,120 0,269 nd nd 0,019 8,100 73,40059 Pearl River Feathers Little Eg. 323 nd nd 850,000 nd nd 82,800 4,590 0,277 nd nd 0,060 8,750 2,67060 Pearl River Feathers Little Eg. ***5 nd nd 238,000 2,830 nd 59,900 0,330 0,136 0,671 22,000 0,094 0,790 158,00061 Pearl River Feathers Little Eg. **1 6,010 nd 1330,000 2,190 6,330 74,300 1,610 0,402 0,885 24,600 0,495 1,760 373,00062 Pearl River Feathers Little Eg. 0_2 nd nd 675,000 nd nd 58,900 15,000 0,055 2,700 nd 0,265 nd nd63 Pearl River Feathers Little Eg. 0_3 17,800 nd 4200,000 2,270 nd 46,800 5,520 0,340 nd nd 0,132 nd 119,00064 Pearl River Feathers Little Eg. 0_6 nd nd 540,000 nd nd 132,000 4,310 0,410 0,646 nd 0,084 22,600 13,00065 Pearl River Sediment Fish ponds -5 0,400 0,179 26,186 105,000 nd 50000,000 19,100 3,160 20,800 10,450 48,150 169,000 17,200 4,885 79,40066 Pearl River Sediment Fish ponds -6 0,616 0,144 28,19767 Pearl River Sediment Fish ponds -1 0,626 0,144 23,202 93,400 40900,000 13,700 5,020 19,200 10,400 50,100 114,000 15,500 3,740 151,00068 Pearl River Sediment Foraging area -2 0,485 0,114 25,074 95,700 2770,000 58600,000 20,700 nd 2,560 22,500 12,500 50,900 79,900 18,200 3,908 124,00069 Pearl River Sediment Foraging area -3 0,469 0,124 26,87670 Pearl River Sediment Foraging area -4 0,537 0,277 22,52071 Pearl River Sediment Foraging area -9 0,073 0,096 15,982 48,600 nd 24100,000 11,100 0,344 1,570 3,200 4,250 19,850 nd 7,630 2,859 30,90072 Pearl River Sediment Foraging area -10 0,388 0,125 19,06073 Pearl River Sediment Foraging area -11 0,575 0,107 15,18674 Pearl River Sediment Park -7 0,131 0,172 23,944 49,300 nd 31500,000 25,400 nd 1,810 3,720 4,430 1,955 61,800 8,620 2,397 106,00075 Pearl River Sediment Park -8 0,407 0,108 22,24376 Poyang Lake Egg Little Eg. Eg1-1 nd 1,460 0,122 0,970 127,600 0,100 2,390 63,00077 Poyang Lake Egg Little Eg. Eg100-27 nd 1,320 2,149 217,800 0,110 4,860 60,60078 Poyang Lake Egg Little Eg. Eg103-28 nd 0,797 0,159 0,730 113,900 0,098 2,900 78,00079 Poyang Lake Egg Little Eg. Eg105-29 nd 0,883 0,156 0,260 109,660 0,070 4,300 57,50080 Poyang Lake Egg Little Eg. Eg106-30 nd 0,813 0,133 0,990 132,100 0,160 2,500 54,30081 Poyang Lake Egg Little Eg. Eg109A-31 nd 0,587 90,200 2,700 0,110 0,350 0,027 2,050 55,10082 Poyang Lake Egg Little Eg. Eg109B-32 104,800 0,090 3,650 121,10083 Poyang Lake Egg Little Eg. Eg109C-33 106,400 0,060 0,018 3,500 59,05084 Poyang Lake Egg Little Eg. Eg109D-34 0,550 103,200 0,081 3,100 47,37085 Poyang Lake Egg Little Eg. Eg109E-35 0,057 0,389 0,523 133,000 0,090 1,970 48,70086 Poyang Lake Egg Little Eg. Eg10A-15 nd 0,593 0,300 141,600 0,090 2,300 51,70087 Poyang Lake Egg Little Eg. Eg10B-16 126,000 3,200 0,140 0,030 0,032 3,050 61,00088 Poyang Lake Egg Little Eg. Eg10C-17 16,900 125,000 2,500 0,160 0,034 0,038 3,420 60,60089 Poyang Lake Egg Little Eg. Eg10D-18 0,477 7,500 143,000 3,200 0,210 0,045 0,045 3,640 71,40090 Poyang Lake Egg Little Eg. Eg10E-19 0,090 0,574 0,280 156,000 2,700 0,170 0,034 0,027 3,330 66,00091 Poyang Lake Egg Little Eg. Eg11-20 nd 1,207 0,083 1,550 96,200 0,096 2,900 58,20092 Poyang Lake Egg Little Eg. Eg111-36 nd 2,131 0,087 0,930 95,100 0,070 4,900 54,00093 Poyang Lake Egg Little Eg. Eg115-37 nd 0,892 0,093 0,760 113,400 0,089 2,300 50,60094 Poyang Lake Egg Little Eg. Eg123-38 nd 0,884 0,077 161,300 0,110 2,250 54,40095 Poyang Lake Egg Little Eg. Eg13-21 nd 0,621 0,091 111,000 0,110 0,009 2,700 51,00096 Poyang Lake Egg Little Eg. Eg15A-22 nd 0,001 31,600 120,000 2,100 0,120 0,035 0,034 3,750 49,10097 Poyang Lake Egg Little Eg. Eg15B-23 15,400 98,000 1,700 0,110 0,029 4,250 52,10098 Poyang Lake Egg Little Eg. Eg15C-24 105,000 1,300 0,130 0,034 0,026 3,710 48,10099 Poyang Lake Egg Little Eg. Eg15D-25 0,315 4,800 108,000 1,700 0,150 0,028 0,028 3,690 61,500100 Poyang Lake Egg Little Eg. Eg18-26 nd 0,532 2,333 1,000 114,500 0,095 2,400 43,400101 Poyang Lake Egg Little Eg. Eg2A-2 nd 0,479 11,800 0,110 0,020 0,027 2,030 52,800

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102 Poyang Lake Egg Little Eg. Eg2B-3 17,100 3,500 0,180 0,025 0,027 2,370 54,100103 Poyang Lake Egg Little Eg. Eg2C-4 14,900 2,400 0,083 0,029 2,260 62,000104 Poyang Lake Egg Little Eg. Eg2D-5 0,217 18,500 113,000 2,240 0,084 0,027 0,028 2,420 55,200105 Poyang Lake Egg Little Eg. Eg2E-6 0,093 0,467 0,109 11,400 95,400 2,430 0,097 0,032 0,032 2,430 55,300106 Poyang Lake Egg Little Eg. Eg3-7 nd 0,898 0,133 0,860 120,200 0,160 2,240 163,200107 Poyang Lake Egg Little Eg. Eg5A-8 nd 0,522 148,000 2,960 0,250 0,033 0,034 2,960 62,300108 Poyang Lake Egg Little Eg. Eg5B-9 113,000 3,400 0,170 0,021 0,033 3,590 65,100109 Poyang Lake Egg Little Eg. Eg5C-10 80,000 3,200 0,120 0,033 0,030 2,970 54,200110 Poyang Lake Egg Little Eg. Eg5D-11 0,298 11,800 124,000 3,700 0,150 0,046 0,029 4,000 51,900111 Poyang Lake Egg Little Eg. Eg5E-12 0,185 1,010 0,100 10,800 108,000 3,200 0,150 0,033 0,032 3,290 58,900112 Poyang Lake Egg Little Eg. Eg8-13 nd 0,909 0,100 0,700 98,600 0,120 0,020 2,300 49,600113 Poyang Lake Egg Little Eg. Eg9-14 nd 0,532 0,124 0,550 190,000 0,300 0,015 2,000 87,500114 Poyang Lake Feathers Little Eg. EG100A2115 Poyang Lake Feathers Little Eg. EG103A116 Poyang Lake Feathers Little Eg. EG105A 1,310 36,500 170,000 5,590 0,830 0,052 0,018 1,780 224,000117 Poyang Lake Feathers Little Eg. EG111A118 Poyang Lake Feathers Little Eg. EG115119 Poyang Lake Feathers Little Eg. EG11A 37,900 77,000 3,800 0,170 0,018 0,010 2,200 204,000120 Poyang Lake Feathers Little Eg. EG123A121 Poyang Lake Feathers Little Eg. EG13A122 Poyang Lake Feathers Little Eg. EG18A123 Poyang Lake Feathers Little Eg. EG1B124 Poyang Lake Feathers Little Eg. EG26A125 Poyang Lake Feathers Little Eg. EG28A126 Poyang Lake Feathers Little Eg. EG31A 0,470 35,000 135,000 7,160 0,190 0,013 0,025 1,500 236,000127 Poyang Lake Feathers Little Eg. EG38B128 Poyang Lake Feathers Little Eg. EG39C 0,930 49,000 110,000 6,750 0,440 0,046 0,012 1,600 175,000129 Poyang Lake Feathers Little Eg. EG3A130 Poyang Lake Feathers Little Eg. EG40B 1,910 28,000 410,000 10,240 0,710 0,022 0,014 1,860 208,000131 Poyang Lake Feathers Little Eg. EG50A132 Poyang Lake Feathers Little Eg. EG8A2 1,260 47,300 97,000 4,410 0,300 0,031 0,008 2,100 195,000133 Poyang Lake Feathers Little Eg. EG9A134 Poyang Lake Prey Fish Little Eg. EGP14/06/99-4 0,375 0,115 2,308 877,000 3,100 0,815 0,250 1,160 0,370 1,200 156,000135 Poyang Lake Prey Fish Little Eg. EGP07/06/99-3 0,717 0,121 1,036136 Poyang Lake Prey Fish Little Eg. EGP24/05/99-6 0,161 0,228 1,610 27,500 740,000 90,000 1,200 0,730 0,100 1,080 0,340 1,450 153,300137 Poyang Lake Prey Fish Little Eg. EGP31/05/99-8 0,174 0,151 1,010 471,500 56,200 0,570 0,830 0,210 1,560 158,000138 Poyang Lake Prey Frog Little Eg. EGFR14/06/99-15 0,177 0,113 12,075139 Poyang Lake Prey Insect larvae Little Eg. EGLL07/06/99-12 0,000 0,000 0,000140 Poyang Lake Prey Insect larvae Little Eg. EGLL14/06/100-11 0,164 0,494 1,372141 Poyang Lake Prey Insect larvae Little Eg. EGLL24/05/99-13 0,170 0,050 1,443142 Poyang Lake Prey Insect larvae Little Eg. EGOL31/05/99-7 0,000 0,000 0,000143 Poyang Lake Prey Shrimp Little Eg. EGG14/06/99-5 0,256 0,121 0,203 736,800 139,600 0,660 0,850 0,162 1,400 0,300 0,870 81,500144 Poyang Lake Prey Shrimp Little Eg. EGG7/06/99 1,600 62,000 1317,000 212,600 0,940 0,130 1,470 0,360 1,130 87,500145 Poyang Lake Prey Shrimp Little Eg. EGG24/05/99-1 0,000 0,000 0,000146 Poyang Lake Prey Shrimp Little Eg. EGG7/06/99-2 0,184 0,122 2,611147 Poyang Lake Prey Shrimp Little Eg. EGS31/05/99-9 0,385 0,145 1,887 871,000 321,200 0,820 0,197 1,590 0,359 1,270 82,100148 Poyang Lake Prey Tadpole Little Eg. EGLR24/05/99-14 0,174 0,112 12,334149 Poyang Lake Prey Tadpole Little Eg. EGT31/05/99-10 0,000 0,000 0,000 15,300 5290,000 104,300 6,900 4,040 1,450 13,000 3,200 2,480 79,900150 Poyang Lake Sediment Ponds PONDS -10 85,333 48,950 3,043 715,770 17,100 11,533 1,560 45,633 10,267 5,023 49,267151 Poyang Lake Sediment Ricefields M.1999.RF1-1 0,210 0,088 25,428 90,667 3,130 222,290 14,900 4,363 45,667 13,600 4,700 65,567152 Poyang Lake Sediment Ricefields M.1999.RF2-2 0,299 0,105 24,095 94,667 3,460 342,420 12,823 8,413 5,910 43,300 11,800 4,633 65,467153 Poyang Lake Sediment Ricefields M.1999.RF3-3 73,200 93,570 2,767 341,670 22,133 3,203 51,100 9,867 2,133 48,333154 Poyang Lake Sediment Ricefields M:1999.RF4-4 88,967 94,450 3,270 312,625 13,000 11,240 1,667 32,633 13,433 3,743 65,000155 Poyang Lake Sediment Ricefields M.1999.RF5-5 83,500 131,510 2,680 323,290 13,633 12,137 1,547 45,300 10,700 3,680 50,000156 Poyang Lake Sediment Ricefields M.1999.RF6-6 88,767 2,923 358,550 10,595 8,943 1,633 29,200 12,233 3,837 57,833157 Poyang Lake Sediment Ricefields M1999RF7-7 80,600 217,730 2,503 362,250 10,367 8,600 1,617 35,167 10,667 4,250 47,233158 Poyang Lake Sediment Ricefields M.1999RF8-8 84,367 113,190 2,737 337,205 15,000 11,400 1,600 41,200 11,150 4,130 71,600159 Poyang Lake Sediment Ricefields M.1999.RF9-9 78,367 52,340 2,863 322,225 13,600 1,633 41,900 10,467 4,023 36,500160 Tai Lake Egg Little Eg. Eg58 (1)-1/5e nd 0,140 0,063

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161 Tai Lake Egg Little Eg. Eg70 (2)-1/6e nd 0,411 0,169 2,390 nd 299,000 nd 105,030 1,110 0,026 nd nd 0,001 3,960 7,490162 Tai Lake Egg Little Eg. Eg22 (3)-1/6e163 Tai Lake Egg Little Eg. Eg93 (4)-1/5e 0,287 225,000 nd 0,039 0,005 1,780 0,002 3,980 0,047164 Tai Lake Egg Little Eg. Eg3 (5)-5e165 Tai Lake Egg Little Eg. Eg1 (6)-1/6e 1,010 nd 104,000 nd 100,130 0,458 0,010 nd nd 0,001 1,907 nd166 Tai Lake Egg Little Eg. Eg2 (7)167 Tai Lake Egg Little Eg. Eg248 (8) nd nd 322,000 nd nd 125,700 1,640 0,015 0,298 nd 0,007 3,550 nd168 Tai Lake Egg Little Eg. Eg6 (9)169 Tai Lake Egg Little Eg. Eg208 (10)170 Tai Lake Egg Little Eg. Eg4 (11) nd 7810,000 212,000 0,600 182,000 1,110 0,023 nd 7,020 0,004 2,880 nd171 Tai Lake Egg Little Eg. Eg58 (12) 0,635 140,200 nd 0,051 0,013 nd 0,002 1,900 52,100172 Tai Lake Egg Little Eg. Ra1a (13)-2/5e 3,640 nd 236,000 nd nd 91,100 0,956 0,059 nd nd 0,157 3,770 nd173 Tai Lake Egg Little Eg. Rb1b (14)-2/5e nd 109,200 nd 0,027 0,008 nd 0,003 2,106 42,600174 Tai Lake Egg Little Eg. Ra2a (15)-2/5e nd nd 174,000 nd nd 72,600 0,684 0,033 nd nd 0,031 2,670 3,520175 Tai Lake Egg Little Eg. Ra2b (16)-2/5e176 Tai Lake Egg Little Eg. Ra3a (17)-2/6e177 Tai Lake Egg Little Eg. Ra3b (18)-2/6e178 Tai Lake Egg Little Eg. Ra4a (19)-2/5e nd 118,240 nd 0,045 0,005 nd 0,002 2,340 52,810179 Tai Lake Egg Little Eg. Ra4b (20)-2/5e 0,530 108,250 nd 0,086 0,004 nd 0,003 2,730 67,980180 Tai Lake Egg Little Eg. Ra5a (21)-2/5e nd 127,000 nd 0,032 0,006 3,110 0,002 2,350 50,600181 Tai Lake Egg Little Eg. Ra5b (22)-2/5e182 Tai Lake Egg Little Eg. Ra6a (23)-2/5e 0,590 121,140 nd 0,040 0,003 nd 0,003 2,960 54,720183 Tai Lake Egg Little Eg. Ra6b (24)-2/5e 121,000 nd 0,034 0,007 nd 0,002 2,796 50,670184 Tai Lake Egg Little Eg. Ra7a (25)-2/6e 1,210 170,000 nd 126,000 0,948 0,022 46,000 nd 0,003 3,480 nd185 Tai Lake Egg Little Eg. Ra7b (26)-2/6e 0,338 124,500 nd 0,037 0,004 nd 0,003 2,160 54,800186 Tai Lake Egg Little Eg. Ra8a (27)-2/5e 0,622 336,300 nd nd 0,010 nd 0,003 2,850 57,900187 Tai Lake Egg Little Eg. Ra8b (28)-2/5e 0,770 348,800 nd nd 0,016 nd 0,006 2,810 82,400188 Tai Lake Egg Little Eg. Ra9a (29)-2/6e189 Tai Lake Egg Little Eg. Ra9b (30)-2/6e190 Tai Lake Egg Little Eg. Eg504 (31)-1/5e 2,860 nd 305,000 nd nd 62,970 0,881 0,041 0,381 nd 0,045 2,460 51,600191 Tai Lake Egg Little Eg. Eg501 (32)-1/5e 0,620 235,000 nd 0,075 nd nd 0,003 2,320 55,400192 Tai Lake Egg Little Eg. Ra10a (33)-2/6e 0,690 143,000 nd 0,038 0,011 nd 0,002 2,270 48,500193 Tai Lake Egg Little Eg. Ra10b (34)-2/6e 0,485 167,400 nd 0,064 nd nd 0,003 2,360 53,700194 Tai Lake Egg Little Eg. Eg308 (35)-1/6e195 Tai Lake Egg Little Eg. Eg273 (36)-1/6e196 Tai Lake Egg Little Eg. Eg244 (37)197 Tai Lake Egg Night Her. EGG001 0,182 0,438 0,115198 Tai Lake Egg Night Her. EGG003 0,108 0,224 0,098199 Tai Lake Egg Night Her. EGG007 0,145 0,506 0,112200 Tai Lake Feathers Little Eg. 1 4,640 191,000 0,003 0,177 0,026 nd 0,014 1,340 168,000201 Tai Lake Feathers Little Eg. 2 2,960 2100,000 0,003 0,260 0,031 nd 0,018 40,430 290,000202 Tai Lake Feathers Little Eg. 3 1,250 109,840 0,001 0,102 0,043 6,980 0,011 1,420 120,650203 Tai Lake Feathers Little Eg. 4 2,580 144,000 0,000 0,214 0,032 nd 0,015 1,630 117,000204 Tai Lake Feathers Little Eg. Eg208b 1,230 156,500 0,003 0,128 0,067 nd 0,034 1,540 187,500205 Tai Lake Feathers Little Eg. Eg22d 2,230 184,300 0,004 0,151 0,038 nd 0,042 1,910 222,500206 Tai Lake Feathers Little Eg. Eg248c nd 135,300 0,007 0,126 0,054 19,200 0,019 2,560 172,000207 Tai Lake Feathers Little Eg. Eg273c 1,840 199,800 nd 0,180 0,056 nd 0,028 2,160 265,000208 Tai Lake Feathers Little Eg. Eg308d 2,580 233,000 0,003 0,570 nd nd 0,015 1,780 294,000209 Tai Lake Feathers Little Eg. Eg501d 4,450 254,000 0,002 0,680 0,028 nd 0,030 2,400 320,500210 Tai Lake Feathers Little Eg. Eg504d 1,110 125,000 0,002 0,208 0,026 nd nd nd nd211 Tai Lake Feathers Little Eg. Eg58d 1,140 136,000 0,002 0,155 0,023 nd 0,016 1,310 217,000212 Tai Lake Feathers Little Eg. Eg70c 1,460 169,000 0,003 0,114 0,017 8,600 0,017 1,480 184,000213 Tai Lake Feathers Little Eg. Eg93b 1,860 112,500 0,003 0,118 0,024 nd 0,020 1,660 176,000214 Tai Lake Prey Fish Little Eg. Fi1 nd 0,047 0,109215 Tai Lake Prey Fish Little Eg. Fi2 1,020 487,600 nd 0,177 0,016 nd 0,024 1,730 212,000216 Tai Lake Prey Fish Little Eg. Fi3 (li)217 Tai Lake Prey Fish Little Eg. Fi4218 Tai Lake Prey Fish Little Eg. Fi5 0,861 763,600 nd 0,216 0,021 nd 0,012 0,468 163,770219 Tai Lake Prey Fish Little Eg. Fi6 2,950 141,000 0,002 0,449 0,018 nd 0,007 1,330 238,000

136

220 Tai Lake Prey Fish Little Eg. Fi7 9,000221 Tai Lake Prey Fish Little Eg. Fi8222 Tai Lake Prey Fish Little Eg. Fi9 1,760 1500,000 nd 0,278 0,040 0,028 2,250 180,000223 Tai Lake Prey Fish Little Eg. Fi10224 Tai Lake Prey Fish Little Eg. Fi11225 Tai Lake Prey Fish Little Eg. Fi12226 Tai Lake Prey Fish Little Eg. Fi13227 Tai Lake Prey Fish Little Eg. Fi14 2,710 194,620 nd 0,096 0,011 0,016 1,650 165,000228 Tai Lake Prey Fish,Shrimp Little Eg. Fi+S1 0,041 0,109 0,106229 Tai Lake Prey Frog Little Eg. Fr1230 Tai Lake Prey Shrimp Little Eg. S1231 Tai Lake Sediment Fish ponds F.P.1 78,200 39400,000 0,003 14,100 7,066 44,650 13,000 2,720 57,560232 Tai Lake Sediment Fish ponds F.P.2 91,510 42000,000 nd 18,025 8,990 51,020 14,460 2,600 63,260233 Tai Lake Sediment Fish ponds F.P.3 91,390 49830,000 0,004 17,660 7,555 45,650 14,270 2,790 67,270234 Tai Lake Sediment Fish ponds F.P.4 84,900 39800,000 nd 12,900 8,140 37,760 14,120 2,040 91,720235 Tai Lake Sediment Fish ponds F.P.5 77,130 38200,000 nd 14,270 7,900 42,170 12,250 2,410 62,200236 Tai Lake Sediment Fish ponds F.P.6 86,160 34900,000 nd 13,455 7,690 49,420 13,510 2,800 65,680237 Tai Lake Sediment Lake L1 0,335 0,123 30,873 116,650 39925,000 0,006 16,820 8,295 55,700 14,170 3,379 150,500238 Tai Lake Sediment Lake L2 0,357 0,111 38,183 100,196 34300,000 0,006 15,300 7,165 81,095 12,100 2,900 162,000239 Tai Lake Sediment Lake L3 88,050 31500,000 0,005 14,700 7,120 58,540 11,900 2,853 121,300240 Tai Lake Sediment Lake L4 84,800 36000,000 nd 14,100 7,390 61,300 13,300 3,190 100,740______________________________________________________________________________________________________________________________________________________________________________________________________________________________

137

____________________________________________________________________________________________________________________________________Appendix B. List of samples collected in Pakistan (from Haleji in 1999, Karachi in 2000, Tounsa in 2000), and their content of metals and other elements (ppm, on dry weight of the sample, nd: not detected, empty cells mean elements not analysed for that sample).

______________________________________________________________________________________________________________________________________________________________________________________________________________________________Ordi Study Material Type Species Code Cad Mercu Lead Chro Cop Iron Manga Arse Sil Bro Co Ce Lantha Nic Scan Sele Zincnal area of mium ry mium per nese nic ver mine balt sium num kel dium niumno. theof samplethesample

241 Haleji Lake Egg Little Eg. Eg/N10E3-2 0,090 0,457 0,170 108,800 0,029 1,700 61,400242 Haleji Lake Egg Little Eg. Eg/N12E2-3 0,232 0,558 0,280 106,400 0,050 0,016 2,100 58,900243 Haleji Lake Egg Little Eg. Eg/N22E2-4 0,064 0,380 0,430 87,900 0,065 2,100 36,300244 Haleji Lake Egg Little Eg. Eg/N26E1-5 0,425 0,555 0,400 112,300 0,025 2,900 39,500245 Haleji Lake Egg Little Eg. Eg/N28E1-6 0,184 0,570 0,100 105,500 0,016 2,450 25,900246 Haleji Lake Egg Little Eg. Eg/N30E1-7 0,109 0,291 0,380 123,100 0,100 2,200 65,900247 Haleji Lake Egg Little Eg. Eg/N31E4-8 0,244 0,539 0,820 172,000 0,070 3,400 51,600248 Haleji Lake Egg Little Eg. Eg/N7E1-1 0,220 0,343 0,150 105,300 0,045 1,800 43,100249 Haleji Lake Egg Interm. Eg. E/N9E2-6 11,000 82,700 1,300 0,090 0,028 1,550 48,300250 Haleji Lake Egg Interm. Eg. Ei/ N1 E1-1 0,269 5,690 1,300 1,530251 Haleji Lake Egg Interm. Eg. Ei/ N20E1-8 nd 0,261 0,151 14,700 97,700 1,800 0,075 0,030 2,380 47,600252 Haleji Lake Egg Interm. Eg. Ei/N11E1-7 0,269 104,300 5,200 0,160 0,030 2,790 48,300253 Haleji Lake Egg Interm. Eg. Ei/N2 E3-2 0,560 72,950 2,800 0,089 0,030 2,490 43,350254 Haleji Lake Egg Interm. Eg. Ei/N21E1-9 0,227 12,600 80,000 1,700 0,050 0,027 2,160 51,500255 Haleji Lake Egg Interm. Eg. Ei/N24E2-10 nd 0,238 nd 9,000 127,000 1,400 0,097 0,032 2,500 53,500256 Haleji Lake Egg Interm. Eg. Ei/N25E3-11 nd 0,161 nd 14,000 104,800 1,100 0,062 0,029 1,520 53,500257 Haleji Lake Egg Interm. Eg. Ei/N27E1-12 nd 0,340 nd 15,400 136,700 1,900 0,099 0,037 3,460 74,300258 Haleji Lake Egg Interm. Eg. Ei/N32E2-13 nd 0,344 nd 0,890 129,200 2,000 0,035 2,660 55,100259 Haleji Lake Egg Interm. Eg. Ei/N32E3-14 100,900 1,800 0,110 0,028 2,640 56,200260 Haleji Lake Egg Interm. Eg. Ei/N34E4-15 0,120 88,300 0,030 1,000 32,900261 Haleji Lake Egg Interm. Eg. Ei/N35E4-16 0,200 57,800 0,043 3,100 32,700262 Haleji Lake Egg Interm. Eg. Ei/N4 E3-3 nd 0,289 0,057 0,390 74,600 1,600 0,076 0,029 2,870 48,100263 Haleji Lake Egg Interm. Eg. Ei/N40E1-17 nd 0,525 nd 0,189 98,000 29,800264 Haleji Lake Egg Interm. Eg. Ei/N41E1-18 0,180 170,300 0,054 2,800 90,800265 Haleji Lake Egg Interm. Eg. Ei/N42E2-19 0,120 80,400 0,035 2,550 41,500266 Haleji Lake Egg Interm. Eg. Ei/N43E1-20 0,220 97,850 0,030 0,016 2,150 40,300267 Haleji Lake Egg Interm. Eg. Ei/N43E2-21 0,240 83,400 0,030 1,700 40,500268 Haleji Lake Egg Interm. Eg. Ei/N5E1-4 nd 0,144 nd 9,270 103,900 0,900 0,079 0,037 1,780 62,100269 Haleji Lake Egg Interm. Eg. Ei/N8E3-5 0,430 12,600 86,000 1,500 0,028 1,660 36,800270 Haleji Lake Egg Interm. Eg. Ei/N33 E2271 Haleji Lake Egg Javanese C. C1N2-1272 Haleji Lake Egg Javanese C. C2N2-2273 Haleji Lake Egg Javanese C. C3N2-3274 Haleji Lake Egg Javanese C. C4N2-4275 Haleji Lake Feathers Little Eg. E.g. 8 0,250 16,520 75,000 2,600 0,210 0,009 2,300 123,000276 Haleji Lake Feathers Little Eg. E.g.9277 Haleji Lake Feathers Little Eg. E.g.11278 Haleji Lake Feathers Little Eg. E.g.12279 Haleji Lake Feathers Little Eg. E.g. 33 0,310 13,400 43,000 1,580 0,047 0,007 1,370 184,000280 Haleji Lake Feathers Little Eg. E.g.34281 Haleji Lake Feathers Little Eg. E.g.41282 Haleji Lake Feathers Little Eg. E.g.42283 Haleji Lake Feathers Little Eg. E.g. 43 0,760 6,150 120,000 4,880 0,230 0,022 1,590 163,000284 Haleji Lake Feathers Interm. Eg. E.i.1285 Haleji Lake Feathers Interm. Eg. E.i.2286 Haleji Lake Feathers Interm. Eg. E.i.3287 Haleji Lake Feathers Interm. Eg. E.i.4

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288 Haleji Lake Feathers Interm. Eg. E.i.5289 Haleji Lake Feathers Interm. Eg. E.i.6290 Haleji Lake Feathers Interm. Eg. E.i. 7 0,280 88,760 42,000 5,340 0,043 0,005 1,300 201,000291 Haleji Lake Feathers Interm. Eg. E.i.13292 Haleji Lake Feathers Interm. Eg. E.i.14293 Haleji Lake Feathers Interm. Eg. E.i.16294 Haleji Lake Feathers Interm. Eg. E.i.17295 Haleji Lake Feathers Interm. Eg. E.i.18296 Haleji Lake Feathers Interm. Eg. E.i.19297 Haleji Lake Feathers Interm. Eg. E.i.20298 Haleji Lake Feathers Interm. Eg. E.i.22299 Haleji Lake Feathers Interm. Eg. E.i.23300 Haleji Lake Feathers Interm. Eg. E.i.24301 Haleji Lake Feathers Interm. Eg. E.i.25302 Haleji Lake Feathers Interm. Eg. E.i.26303 Haleji Lake Feathers Interm. Eg. E.i.27304 Haleji Lake Feathers Interm. Eg. E.i.28305 Haleji Lake Feathers Interm. Eg. E.i.29306 Haleji Lake Feathers Interm. Eg. E.i. 30 0,150 66,100 53,800 1,700 0,069 0,004 1,360 264,000307 Haleji Lake Feathers Interm. Eg. E.i.31308 Haleji Lake Feathers Interm. Eg. E.i.32309 Haleji Lake Feathers Interm. Eg. E.i.35310 Haleji Lake Feathers Interm. Eg. E.i.36311 Haleji Lake Feathers Interm. Eg. E.i.37312 Haleji Lake Feathers Interm. Eg. E.i.38313 Haleji Lake Feathers Interm. Eg. E.i.39 0,170 10,230 41,000 1,130 0,034 0,005 0,870 186,000314 Haleji Lake Feathers Interm. Eg. E.i.40315 Haleji Lake Feathers Interm. Eg. E.i.44316 Haleji Lake Feathers Interm. Eg. E.i.45317 Haleji Lake Feathers Interm. Eg. E.i.46318 Haleji Lake Feathers Interm. Eg. E.i.47319 Haleji Lake Feathers Interm. Eg. E.i.48320 Haleji Lake Prey Fish Interm. Eg. Barbus-7321 Haleji Lake Prey Fish Interm. Eg. Barbus-19322 Haleji Lake Prey Fish Interm. Eg. Colisa-16323 Haleji Lake Prey Fish Interm. Eg. Colisa-17324 Haleji Lake Prey Fish Interm. Eg. Colisa-18325 Haleji Lake Prey Fish Interm. Eg. Gloss8326 Haleji Lake Prey Fish Interm. Eg. Gloss9327 Haleji Lake Prey Fish Interm. Eg. Glos10328 Haleji Lake Prey Fish Interm. Eg. Glos11329 Haleji Lake Prey Fish Interm. Eg. Glos12330 Haleji Lake Prey Fish Interm. Eg. Glos13331 Haleji Lake Prey Fish Interm. Eg. Oreoc2332 Haleji Lake Prey Fish Interm. Eg. Oreoc3333 Haleji Lake Prey Fish Interm. Eg. Oreoc4334 Haleji Lake Prey Fish Interm. Eg. Oreoc5335 Haleji Lake Prey Fish Interm. Eg. Oreoc6336 Haleji Lake Prey Shrimp Interm. Eg. Carrid1 0,042 0,120 0,233337 Haleji Lake Prey Shrimp Interm. Eg. Carrid14 0,039 0,098 0,190338 Haleji Lake Prey Shrimp Interm. Eg. Carrid15 0,070 0,137 0,629339 Karachi Egg Little Eg. Egu1a nd 0,138 0,047 nd nd 99,000 nd 30,800 nd nd nd nd 0,001 1,690 nd340 Karachi Egg Little Eg. Egu1b nd 0,153 0,044341 Karachi Egg Little Eg. Egu2a nd 0,174 nd 0,319 nd 150,000 nd nd 42,500 nd 0,042 nd nd 0,002 2,640 nd342 Karachi Egg Little Eg. Egu2b nd 0,159 0,045343 Karachi Egg Little Eg. Egu5a nd nd 110,000 0,324 38,000 0,082 0,018 nd nd 0,003 3,070 32,800344 Karachi Egg Little Eg. Egu5b345 Karachi Egg Little Eg. Egu9a 1410,000 nd 51,300 nd346 Karachi Egg Little Eg. Egu9b

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347 Karachi Egg Little Eg. Egu21a nd nd 92,100 nd nd 44,800 nd 0,135 0,321 nd 0,005 5,610 2,710348 Karachi Egg Little Eg. Egu21b349 Karachi Egg Little Eg. Egu22 1,820 nd 741,000 nd nd 29,100 nd 0,053 nd nd 0,013 2,160 140,000350 Karachi Egg Little Eg. Egu50a 1,100 nd 360,000 0,231 nd 46,100 nd 0,014 nd 22,900 0,023 2,980 nd351 Karachi Egg Little Eg. Egu50b352 Karachi Egg Little Eg. Egu53a nd 183,000 1,320 nd 29,800 0,141 nd 0,366 nd 0,036 2,130 4,440353 Karachi Egg Little Eg. Egu53b354 Karachi Egg Little Eg. Egu54a nd nd 156,000 nd nd 50,600 0,110 0,024 nd nd nd 3,350 nd355 Karachi Egg Little Eg. Egu54b356 Karachi Egg Little Eg. Egu55 nd 3300,000 76,400 0,448 nd 98,000 0,005 0,098 nd nd 0,007 2,870 nd357 Karachi Egg Little Eg. Egu56a nd nd 183,000 0,509 nd 44,700 0,678 0,072 nd nd 0,014 3,810 329,000358 Karachi Egg Little Eg. Egu56b359 Karachi Egg Little Eg. Egu57a 3,480 nd 99,500 0,239 0,637 51,500 nd 0,045 0,279 nd 0,002 3,160 14,700360 Karachi Egg Little Eg. Egu57b361 Karachi Egg Little Eg. Egu58a nd nd 481,000 nd nd 34,300 nd 0,073 0,317 nd 0,008 2,240 222,000362 Karachi Egg Little Eg. Egu58b363 Karachi Egg Little Eg. Egu59a nd nd 191,000 0,485 nd 57,900 nd nd nd 9,530 0,010 5,050 nd364 Karachi Egg Little Eg. Egu59b365 Karachi Egg Little Eg. Egu60 nd nd 581,000 0,295 nd 43,500 nd 0,037 nd nd 0,005 8,370 0,406366 Karachi Egg Little Eg. Egu61a nd 0,837 43,300 nd367 Karachi Egg Little Eg. Egu61b368 Karachi Egg Little Eg. Egu62a nd nd 114,000 0,272 48,300 0,188 0,022 0,480 nd 0,006 3,140 30,500369 Karachi Egg Little Eg. Egu62b370 Karachi Egg Little Eg. Egu63b nd nd 117,200 nd 51,200 0,081 0,008 nd nd 0,001 3,790 11,600371 Karachi Egg albumen Little Eg. Egu3alb. nd 4800,000 122,700 nd 69,400 nd 0,183 nd nd 0,002 1,460 nd372 Karachi Egg albumen Little Eg. Egu63a alb. 4,540 nd 23,600 nd nd 80,200 2,050 0,097 0,280 nd nd 11,240 nd373 Karachi Egg albumen Little Eg. Egu63c alb. nd nd 121,000 nd nd 79,900 0,104 0,094 nd nd 0,029 1,560 nd374 Karachi Egg yolk Little Eg. Egu3yolk nd nd 295,000 0,175 0,751 24,000 2,170 0,078 nd nd 0,006 7,500 287,000375 Karachi Egg yolk Little Eg. Egu63a yolk nd nd 240,000 0,389 27,100 0,153 0,009 nd nd 0,002 4,340 79,000376 Karachi Egg yolk Little Eg. Egu63c yolk nd 120,800 nd 16,000 0,338 0,017 0,622 nd 0,004 1,430 84,800377 Karachi Feathers Little Eg. Egu 100 15,500 nd 109,000 nd nd 64,300 15,900 0,351 1,420 nd nd 12,000 609,000378 Karachi Feathers Little Eg. Egu1a (a+b) nd 95,900 nd nd 59,300 4,400 0,191 1,800 nd nd 7,460 nd379 Karachi Feathers Little Eg. Egu 1b380 Karachi Feathers Little Eg. Egu200a(a+b) nd nd 938,000 0,654 nd 74,000 5,010 0,540 nd nd 0,072 18,700 242,000381 Karachi Feathers Little Eg. Egu 200b382 Karachi Feathers Little Eg. Egu4a(a+b) 7,530 nd 307,000 nd nd 69,500 7,880 0,216 nd nd 0,048 2,160 435,000383 Karachi Feathers Little Eg. Egu 4b384 Karachi Feathers Little Eg. Egu 5a nd 36100,000 1400,000 nd nd 57,400 14,000 nd nd nd 0,005 nd 227,000385 Karachi Feathers Little Eg. Egu66a(a+b) 7,380 nd 328,000 1,550 nd 82,100 5,580 0,196 nd nd 0,020 2,450 152,000386 Karachi Feathers Little Eg. Egu 66b387 Karachi Feathers Little Eg. Egu68a(a+b) 6,110 nd 431,000 2,620 1,360 81,300 5,580 0,436 nd nd 0,054 7,020 189,000388 Karachi Feathers Little Eg. Egu 68b389 Karachi Feathers Little Eg. Egu69a(a+b) 9,710 nd 1050,000 0,777 nd 71,600 8,920 0,572 nd nd 0,066 1,850 1710,000390 Karachi Feathers Little Eg. Egu 69b391 Karachi Feathers Little Eg. Egu 70b nd nd 1,280 nd 75,200 9,480 0,307 nd nd nd 23,200 nd392 Karachi Feathers Little Eg. Egu 7b 9,380 nd 782,000 0,723 nd 42,700 5,450 nd nd nd 0,009 1,370 nd393 Karachi Feathers Little Eg. Egu 80a 23,100 nd 2130,000 nd nd 96,400 14,800 0,441 nd nd 0,392 4,850 nd394 Karachi Feathers Little Eg. Egu8a(a+b) nd nd 1130,000 nd nd 40,200 2,590 0,215 nd nd 0,041 nd 449,000395 Karachi Feathers Little Eg. Egu 8b396 Karachi Prey Fish Little Eg. F1 0,072 0,549 3,589397 Karachi Prey Fish Little Eg. F2 0,103 0,533 4,322398 Karachi Prey Fish Little Eg. F3 0,131 0,641 6,366399 Karachi Sediment Channel C.K.1400 Karachi Sediment Channel C.K.2401 Karachi Sediment Channel C.K.3 174,000 1300,000 37500,000 7,460 0,278 33,000 18,800 9,790 22,100 47,400 11,500 2,914 88,700402 Karachi Sediment Mud G.B.1 0,228 1,724 22,904403 Karachi Sediment Mud G.B.2 0,316 2,675 47,718404 Karachi Sediment Mud G.B.3 0,120 0,775 6,236 308,000 nd 15900,000 4,510 nd 23,100 6,460 2,190 33,600 38,800 6,300 2,975 7,230405 Karachi Sediment Channel O.C.1

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406 Karachi Sediment Channel O.C.2 245,000 nd 44800,000 19,100 nd 7,670 22,000 9,800 34,300 62,100 15,300 3,430 119,000407 Karachi Sediment Channel O.C.3408 Tounsa Egg Cattle Eg. Bi6 nd 0,034 0,106 nd nd 110,000 nd 0,882 22,000 0,020 0,022 nd nd 0,039 2,000 12,700409 Tounsa Egg Cattle Eg. Bi14 nd nd 83,500 nd nd 6,150 0,006 0,005 0,191 nd 0,001 3,760 20,100410 Tounsa Egg Cattle Eg. Bi21 nd nd 123,000 0,218 nd 10,270 nd 0,013 nd nd 0,009 2,190 16,400411 Tounsa Egg Cattle Eg. Bi23 nd nd 96,300 nd 5,560 0,008 0,009 nd nd 0,004 3,620 nd412 Tounsa Egg Cattle Eg. Bi25 nd nd 155,000 nd 72,600 0,195 0,021 nd nd 0,004 3,390 63,000413 Tounsa Egg Cattle Eg. Bi30a nd 136,000 nd nd 5,950 0,058 0,022 0,220 nd 0,023 2,313 22,900414 Tounsa Egg Cattle Eg. Bi30b nd nd 131,000 nd nd 10,500 nd 0,016 nd nd 0,010 2,210 28,600415 Tounsa Egg Cattle Eg. Bi31 nd nd 135,000 nd nd 8,180 nd 0,011 nd nd 0,007 2,026 25,100416 Tounsa Egg Cattle Eg. Bi35 nd nd 135,000 nd nd 9,002 nd 0,016 nd nd 0,003 2,487 43,200417 Tounsa Egg Cattle Eg. Bi54 nd 108,000 nd 4,896 0,054 0,011 0,245 nd 0,005 2,520 29,000418 Tounsa Egg Little Eg. Eg2 nd 0,199 0,177 nd nd 105,300 nd 51,100 0,031 0,017 0,096 nd 0,006 3,510 5,820419 Tounsa Egg Little Eg. Eg17 nd nd 125,000 nd nd 18,500 0,053 0,026 0,201 nd 0,033 1,190 1,101420 Tounsa Egg Little Eg. Eg18 nd nd 221,000 nd 76,300 0,045 0,010 nd nd 0,006 4,137 28,100421 Tounsa Egg Little Eg. Eg29 1,080 nd 183,000 0,343 nd 54,100 0,021 0,033 nd nd 0,024 4,140 9,060422 Tounsa Feathers Cattle Eg. Bi21a 9,930 252,000 nd nd 25,100 5,980 0,342 nd nd nd 5,700 nd423 Tounsa Feathers Cattle Eg. Bi21b nd 199,000 nd nd 16,300 6,560 0,156 1,460 nd 0,005 4,180 139,000424 Tounsa Feathers Cattle Eg. Bi22a nd nd 1160,000 nd nd 10,500 9,580 0,369 nd nd 0,406 5,130 nd425 Tounsa Feathers Cattle Eg. Bi24a nd nd 110,000 nd nd 28,000 8,670 0,401 nd nd 0,035 10,400 12,300426 Tounsa Feathers Cattle Eg. Bi47 nd 1650,000 nd nd 11,000 9,790 0,370 nd nd 0,498 6,980 nd427 Tounsa Feathers Cattle Eg. Bi52a nd nd 388,000 nd 21,000 8,700 nd nd nd 0,031 8,380 nd428 Tounsa Feathers Cattle Eg. Bi53a 7,290 5550,000 1260,000 nd 37,000 8,890 0,051 nd nd 0,042 3,180 nd429 Tounsa Feathers Cattle Eg. Bi54a 11,300 nd 585,000 nd 34,100 15,500 0,043 0,710 nd 0,056 9,740 nd430 Tounsa Feathers Cattle Eg. Bi6 17,200 nd 1250,000 nd nd 16,000 7,670 0,256 0,165 nd 0,270 6,400 384,000431 Tounsa Feathers Cattle Eg. Bi61a 7,300 nd 355,000 nd nd 26,200 8,200 0,131 nd 113,000 nd 11,000 220,000432 Tounsa Feathers Cattle Eg. Bi68a nd nd 1720,000 nd 5,050 34,900 7,610 0,186 0,604 nd nd 21,700 nd433 Tounsa Feathers Cattle Eg. Bi77a nd nd 2070,000 nd nd 31,300 6,040 nd 0,545 nd 0,037 12,300 256,000434 Tounsa Feathers Cattle Eg. Bi85a 10,500 nd 594,000 1,230 17,100 10,400 0,075 nd nd 0,032 5,130 428,000435 Tounsa Feathers Little Eg. Eg14a nd nd 260,000 nd 19,000 19,300 0,093 nd nd 0,025 7,900 113,000436 Tounsa Feathers Little Eg. Eg64a nd 70,300 nd nd 14,800 4,090 nd 2,980 nd 0,009 27,700 nd437 Tounsa Feathers Little Eg. Eg65 12,400 nd 695,000 1,120 39,000 9,540 nd 0,867 nd 0,031 3,350 nd438 Tounsa Prey Insects Cattle Eg. Tcr 0,119 0,025 0,903 5,930 nd 1700,000 nd nd 25,100 1,530 0,350 1,630 nd 0,581 3,487 180,000439 Tounsa Prey Fish Cattle Eg. Tfi 2,570 nd 1046,300 1,350 nd 15,300 0,965 0,228 0,453 nd 0,157 2,760 78,000440 Tounsa Prey Frog Cattle Eg. Tfr 3,100 nd 701,000 0,401 nd 12,600 0,671 0,275 0,621 nd 0,261 2,087 77,900441 Tounsa Prey Insects Cattle Eg. Tin 0,034 0,018 0,872 8,380 1240,000 2190,000 0,713 nd 33,600 1,380 0,391 2,210 nd 0,788 1,129 28,400442 Tounsa Prey Mice Cattle Eg. Tmo 4,400 nd 1620,000 0,536 nd 10,900 1,510 0,346 1,150 17,100 0,511 2,924 51,500443 Tounsa Sediment Channel C1 0,057 nd 3,842 169,000 2160,000 39100,000 4,120 nd 4,510 12,300 4,045 94,400 nd 15,800 8,467 54,800444 Tounsa Sediment Channel C2 0,061 nd 4,609445 Tounsa Sediment Channel C3 0,091 0,020 4,121446 Tounsa Sediment Channel C4447 Tounsa Sediment Ponds P.1 104,000 3760,000 36100,000 4,370 2,550 13,100 4,860 49,250 89,600 14,000 4,160 12,100448 Tounsa Sediment Ponds P.2449 Tounsa Sediment Ponds P.3450 Tounsa Sediment Ricefields RF.1 107,000 nd 38900,000 6,300 0,843 2,840 15,600 7,400 53,500 49,000 15,100 3,240 48,500451 Tounsa Sediment Ricefields RF.2452 Tounsa Sediment Ricefields RF.3______________________________________________________________________________________________________________________________________________________________________________________________________________________________

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Appendix C. List of samples collected in China (from Guandong in 2000, Poyang lake 1999, Wuxi 2000), and their content of organic contaminants (ppb, or ng/g on dry weight basis, empty cells mean not detected at the equipment detection limits). If fresh weight of the analyzed sample was available it has been included with the corresponding dry weight to make possible the transformation to concentrations on wet weight basis.

YEA YearNES Nest id.#EGG Egg id.#LAB Original labelLOC Locality

11 Haleji Lake12 Taunsa Barrage13 Karachi Ghas Bunder21 Lake Poyang (Nanchang)22 Lake TaiHu (Wuxi)23 Ecol. Park (Guandong)

SPE Species1 Egretta garzetta2 Egretta intermedia3 Egretta gularis4 Bubulcus ibis5 Nycticorax nycticorax6 Phalacrocorax niger21 Fishes22 Shrimps23 Fish and shrimp24 Tadpoles25 Frogs26 Mice27 Coleoptera28 Odonata29 Crickets41 Lake42 Fishpond43 Pond44 Ricefield45 Channel46 Mud47 Foraging area48 Seepage lagoon

TYP Type1 Egg content2 Preys3 Sediments

D_C Dry weight (g)F_C Fresh weight (g)AHC alfa-HCH (ng/g)GHC gama-HCH (ng/g)BHC beta-HCH (ng/g)DHC delta-HCH (ng/g)HEP Heptachlor (ng/g)HEX Heptachlor-epoxi (ng/g)ALDR Aldrin (ng/g)AES alfa-Endosulfán (ng/g)BES beta-Endosulfán (ng/g)

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PPDDE pp-DDE (ng/g)PPDDD pp-DDD (ng/g)PPDDT pp-DDT (ng/g)SHCB HCB (ng/g)SHCH sum HCHs (ng/g)SCIC sum Cyclodiene pest. (ng/g)SDDT sum DDTs (ng/g)SPCB sum PCBs (ng/g)

______________________________________________________________________________________________________________________________________________________________________________________________________________________________YEA NES EGG LAB LOC SPE TYP D_C F_C AHC GHC BHC DHC HEP HEX ALD AES BES PPDDE PPDDD PPDDT SHCB SHCH SCIC SDDT SPCB

99 1 9 EgM1 EGG 21 1 1 4,2740 22,2960 1901,4 17,4 1901,4 28,899 2 1 EgM2A EGG 21 1 1 4,1330 22,3870 46,4 4,8 3049,9 9,5 51,2 3049,999 2 2 EgM2B EGG 21 1 1 4,1540 22,4380 73,8 2335,5 27,6 7,1 73,8 2363,199 2 3 EgM2C EGG 21 1 1 4,0490 21,9640 65,7 4356,1 11,2 65,7 4356,1 5,799 2 4 EgM2D EGG 21 1 1 4,3870 22,8910 42,4 2860,4 29,7 10,3 42,4 2890,1 7,999 2 5 EgM2E EGG 21 1 1 4,4190 22,8630 2504,3 29,1 7,9 2533,499 3 9 EgM3 EGG 21 1 1 4,0520 21,1070 2062,4 23,1 2062,499 5 1 EgM5A EGG 21 1 1 3,4810 19,5960 43,6 816,9 7,0 43,6 816,9 7,999 5 2 EgM5B EGG 21 1 1 3,5980 20,6020 63,8 2146,1 46,4 13,7 63,8 2192,5 74,499 5 3 EgM5C EGG 21 1 1 3,2860 19,4430 77,3 1602,9 43,1 17,0 77,3 1646,0 63,899 5 4 EgM5D EGG 21 1 1 3,6620 21,2290 21,5 1225,3 11,8 15,1 12,8 21,5 1252,3 40,799 5 5 EgM5E EGG 21 1 1 3,3630 18,0750 23,3 1684,9 35,3 15,3 23,3 1720,2 32,399 8 9 EgM8 EGG 21 1 1 4,2160 22,7820 35,6 29,5 4042,3 25,1 28,8 65,2 4067,5 5,499 9 9 EgM9 EGG 21 1 1 4,2060 22,4680 68,1 29,4 6435,5 34,9 97,5 6435,599 10 1 EgM10A EGG 21 1 1 3,7000 20,2370 85,0 5890,1 33,1 18,0 85,0 5923,2 21,499 10 2 EgM10B EGG 21 1 1 3,8820 22,0390 19,2 7642,8 36,7 22,2 24,0 19,2 7701,7 9,899 10 3 EgM10C EGG 21 1 1 3,9040 21,0820 6199,9 6199,999 10 4 EgM10D EGG 21 1 1 3,7680 22,8660 24,6 7990,0 127,8 11,0 24,6 8117,7 36,099 10 5 EgM10E EGG 21 1 1 3,8880 21,4220 274,7 8059,5 55,6 23,7 274,7 8115,0 32,299 11 9 EgM11 EGG 21 1 1 3,4610 18,6780 2830,0 35,1 2830,099 13 9 EgM13 EGG 21 1 1 3,5310 18,3680 2634,0 17,6 21,8 2651,5 18,099 15 1 EgM15A EGG 21 1 1 4,0070 22,8740 5005,7 51,0 28,4 5056,7 84,099 15 2 EgM15B EGG 21 1 1 3,8680 20,3740 49,3 4575,0 75,6 18,8 49,3 4650,6 226,899 15 3 EgM15C EGG 21 1 1 4,0000 21,9190 50,7 5,8 5177,4 113,3 21,8 50,7 5,8 5290,7 316,599 15 4 EgM15D EGG 21 1 1 4,1180 21,8910 52,2 4707,5 109,3 30,3 52,2 4816,8 144,099 18 9 EgM18 EGG 21 1 1 4,1020 21,4070 1809,9 16,1 27,0 1826,099 100 9 EgM100 EGG 21 1 1 3,6540 21,1910 3476,3 14,4 3476,399 103 9 EgM103 EGG 21 1 1 4,5800 25,3300 7959,2 24,8 12,0 7983,999 105 9 EgM105 EGG 21 1 1 4,2790 23,5450 1855,4 5,2 1855,499 106 9 EgM106 EGG 21 1 1 3,7030 18,2710 1657,0 7,6 1657,099 109 1 EgM109A EGG 21 1 1 4,1310 21,4990 39,3 3915,5 29,1 72,0 39,3 3944,6 11,999 109 2 EgM109B EGG 21 1 1 4,3730 22,0030 3258,9 59,7 3258,999 109 3 EgM109C EGG 21 1 1 4,3180 22,0500 32,8 3175,5 8,3 70,1 32,8 3183,8 11,999 109 4 EgM109D EGG 21 1 1 4,5630 23,6680 43,1 3496,6 82,1 43,1 3496,699 109 5 EgM109E EGG 21 1 1 4,1560 22,6990 3185,9 54,6 3185,999 111 9 EgM111 EGG 21 1 1 3,0690 18,4030 3592,3 9,3 3592,3 8,799 115 9 EgM115 EGG 21 1 1 3,5910 22,6140 2254,7 27,1 2254,799 123 9 EgM123 EGG 21 1 1 3,3620 21,9580 2323,4 19,5 26,7 2342,999 EG MP 14-6-99 21 21 2 2,7650 11,5080 11,0 50,0 14,0 11,0 50,099 EG MP 7-6-99 21 21 2 ,8070 5,1380 38,0 19,0 38,099 EG MP 31-5-99 21 21 2 3,0480 11,9260 87,0 8,0 16,0 95,099 EG MP 24-5-99 21 21 2 3,9590 14,8700 94,0 17,0 4,0 111,099 EG MG 14-5-99 21 22 2 4,8900 22,3270 9,0 11,0 13,0 9,0 11,099 EG MG 7-6-99 21 22 2 6,0730 24,7340 9,0 12,0 9,099 EG MS 31-5-99 21 22 2 3,6590 15,6680 11,0 18,0 11,099 EG MG 24-5-99 21 22 2 1,5270 6,0230 18,099 EG MLR 24-5-99 21 24 2 1,0210 3,3440 10,0 18,0 10,0

143

99 EG MT 31-5-99 21 24 2 3,5770 11,0830 158,0 90,0 19,0 248,099 EG MFR 14-5-99 21 25 2 1,5630 6,2320 8,0 17,0 8,099 EG MOL 31-5-99 21 28 2 ,5380 2,3140 14,0 8,0 15,0 14,0 8,099 EG MLL 14-6-99 21 28 2 ,1370 ,5800 53,099 EG MLL 7-6-99 21 28 2 ,4060 1,6180 61,099 EG MLL 24-5-99 21 28 2 ,3790 1,6390 14,099 POND 21 43 3 3,4 157,0 3165,0 3792,0 41675,0 1,3 160,4 48632,099 RF I 21 44 3 3,3 1,8 3,399 RF II 21 44 3 6,2 ,9 1,3 7,199 RF III 21 44 3 1,6 1,699 RF IV 21 44 3 6,1 3,6 1,4 9,799 RF V 21 44 3 1,5 1,6 1,599 RF VI 21 44 3 ,9 7,4 2,0 ,9 7,499 RF VII 21 44 3 4,0 1,6 4,099 RF VIII 21 44 3 1,5 1,4 1,599 RF IX 21 44 3 1,400 1 9 Eg 001 w/00 22 1 1 4,3900 22,6300 8,2 24,1 84,9 8,3 15,0 1834,0 10,0 13,9 32,2 108,2 1844,0 398,700 3 9 Eg 003 w/00 22 1 1 3,5400 19,0400 34,7 35,3 64,0 7,7 16,0 1818,0 53,8 33,9 70,0 87,7 1871,8 141,000 4 9 Eg 004 w/00 22 1 1 3,4700 19,1900 23,7 38,6 42,4 6,6 1829,8 37,1 21,1 62,3 49,0 1866,9 185,300 5 9 Eg 005 w/00 22 1 1 4,0800 21,1500 13,0 61,6 52,8 45,1 1730,6 120,7 124,6 74,7 97,9 1851,2 298,100 6 9 Eg 006 w/00 22 1 1 4,1700 21,3800 15,4 73,6 49,9 61,1 1753,1 120,8 192,0 89,0 111,1 1873,9 270,200 22 9 Eg22 w/00 22 1 1 4,4600 22,3500 17,4 57,5 68,5 5,8 1763,2 73,3 32,9 74,9 74,3 1836,5 179,200 58 9 Eg 58 w/00 22 1 1 3,7800 19,1400 10,7 5,4 69,4 4,4 41,4 390,8 11,3 16,0 115,1 390,8 440,700 70 9 Eg 70 w/00 22 1 1 4,1500 21,1500 10,6 62,7 5,4 2,1 7,2 1516,9 79,9 31,7 73,3 14,7 1596,8 211,700 93 9 Eg 93 w/00 22 1 1 4,0700 21,9300 49,0 98,2 48,0 28,8 2383,7 57,1 262,0 30,1 147,2 76,7 2702,9 102,000 208 9 Eg 208 w/00 22 1 1 4,1300 21,3400 44,7 80,3 110,8 36,7 17,6 1608,9 12,0 55,3 235,8 54,3 1620,8 322,000 248 9 Eg 248 w/00 22 1 1 4,5500 22,7600 45,5 79,8 13,2 1858,9 78,9 12,2 45,5 93,0 1937,8 167,100 505 9 Eg 20000505 w/00 22 1 1 6,8 35,9 99,4 15,5 19,6 1928,1 11,1 22,0 42,7 134,5 1939,2 487,400 10019 Eg-Rb 001 w/00 22 1 1 4,2100 22,7500 24,7 93,3 97,6 57,4 26,5 4187,1 357,7 1073,2 18,2 118,1 181,5 5618,0 1436,100 10019 Eg-Ra 001 w/00 22 1 1 3,7500 19,5800 10,2 68,6 54,5 21,8 6,1 1581,2 112,3 36,4 133,3 27,9 1693,5 3017,300 10019 Eg-Rc 001 w/00 22 1 1 4,0600 21,8300 19,0 97,6 9,5 2,9 5,6 1701,9 64,1 53,5 116,6 18,0 1766,0 813,800 10029 Eg-Rb 002 w/00 22 1 1 4,3000 23,7600 15,3 101,5 101,9 93,3 25,3 11886,2 307,8 1279,6 28,8 116,8 220,4 13473,6 1186,300 10029 Eg-Ra 002 w/00 22 1 1 3,7700 19,8800 11,1 58,0 56,3 3,1 5,5 1834,6 119,0 42,3 69,0 64,9 1953,5 3117,500 10029 Eg-Rc 002 w/00 22 1 1 4,0800 21,8800 14,9 104,7 81,7 4,8 9,0 1750,9 18,8 44,2 119,6 95,5 1769,6 977,100 10039 Eg-Rb 003 w/00 22 1 1 4,2500 21,4800 39,8 80,3 29,4 983,7 11,8 221,5 120,1 29,4 995,6 493,600 10039 Eg-Ra 003 w/00 22 1 1 4,3100 21,4600 25,9 65,1 64,7 20,4 1594,6 22,5 13,7 51,7 90,9 85,1 1630,8 360,100 10039 Eg-Rc 003 w/00 22 1 1 4,3900 22,5800 9,2 149,7 65,7 42,8 5,7 2481,3 99,5 39,3 224,6 48,4 2580,8 929,700 10049 Eg-Rb 004 w/00 22 1 1 4,2300 20,9800 53,7 91,0 29,2 2,7 25,2 1109,6 5,8 199,0 144,8 57,1 1115,4 552,600 10049 Eg-Ra 004 w/00 22 1 1 3,9300 20,2200 10,5 54,4 88,7 9,9 2,8 5,2 1560,7 8,2 15,8 153,6 18,0 1568,8 330,000 10049 Eg-Rc 004 w/00 22 1 1 4,5200 22,8700 8,9 171,0 115,8 3,5 2721,0 50,3 179,9 119,3 2721,0 1011,700 10059 Eg-Rb 005 w/00 22 1 1 4,3200 12,0900 19,1 51,0 85,6 2,2 60,2 4,2 11,5 6019,8 30,4 492,5 152,2 155,7 78,1 6542,7 759,100 10059 Eg-Ra 005 w/00 22 1 1 3,6300 17,8200 13,3 112,1 5,1 41,1 1703,9 66,0 20,8 24,2 125,4 46,2 1790,7 107,800 10059 Eg-Rc 005 w/00 22 1 1 4,4700 24,0300 10,9 33,6 74,0 5,2 6,5 1030,6 31,2 118,5 11,7 1030,6 298,300 10069 Eg-Rb 006 w/00 22 1 1 4,3500 22,5100 11,3 44,3 145,4 8,7 16,8 9,0 6173,4 18,9 434,1 53,7 201,0 34,4 6626,4 648,100 10069 Eg-Ra 006 w/00 22 1 1 3,7600 18,5500 22,4 137,0 111,7 74,3 3,7 25,4 1707,1 82,2 20,5 271,1 103,4 1789,3 87,500 10069 Eg-Rc 006 w/00 22 1 1 5,0000 23,9600 15,5 31,0 89,1 7,4 948,0 36,1 46,4 96,5 948,0 209,700 10079 Eg-Ra 007 w/00 22 1 1 4,0400 21,1800 10,7 35,6 132,9 1,1 67,1 13,1 18,2 2920,1 95,0 13,5 179,3 99,6 3015,1 718,500 10089 Eg-Ra 008 w/00 22 1 1 3,8300 19,9900 16,6 38,4 106,3 75,9 4,8 29,6 3002,3 42,3 12,1 161,2 110,3 3044,6 805,500 10389 Eg D308 w/00 22 1 1 3,9300 20,4500 6,9 80,4 71,1 31,1 6,7 1875,9 7,9 12,0 158,3 37,7 1883,8 683,500 12449 Eg C244 w/00 22 1 1 4,0700 21,9000 6,7 53,9 99,3 3,5 2,9 947,5 14,6 60,6 105,8 947,5 335,600 15019 Eg CE 501 w/00 22 1 1 8,9400 20,3800 26,9 182,5 123,7 5,7 2343,7 27,1 209,4 129,3 2343,7 647,400 15049 Eg-CE 504 W/00 22 1 1 3,5400 19,4100 4,6 56,5 78,8 5909,7 21,2 14,7 61,1 78,8 5930,9 402,699 1 9 YTZHNNEGG001 22 5 1 1167,0 10,0 6688,0 113,0 93,0 1167,0 10,0 6801,0 220,099 2 9 YTZHNNEGG003 22 5 1 145,0 3178,0 25,0 30,0 145,0 3203,0 8,099 7 9 YTZHNNEGG007 22 5 1 4015,0 161,0 17,0 4176,0 505,000 Wuxi col. Fi 1 22 21 2 37,2 53,7 37,2 53,7 8,400 Wuxi col. Fi 2 22 21 2 5,1 5,3 184,8 26,9 16,8 10,4 211,700 Wuxi col. Fi 3 22 21 2 171,2 10,2 181,4 12,800 Wuxi col. Fi 4 22 21 2

144

00 Wuxi col. Fi 5 22 21 2 19,3 8,3 19,3 8,3 76,500 Wuxi col. Fi 6 22 21 2 5,7 16,4 5,7 16,4 9,200 Wuxi col. Fi 7 22 21 2 141,0 15,2 156,2 8,200 Wuxi col. Fi 8 22 21 2 3,3 35,5 3,2 3,3 35,5 8,800 Wuxi col. Fi 9 22 21 2 4,2 72,0 8,2 4,2 80,1 8,300 Wuxi col. Fi 10 22 21 2 2,1 37,7 19,1 4,6 2,1 56,8 15,500 Wuxi col. Fi 11 22 21 2 3,8 2,2 172,6 6,0 172,6 4,300 Wuxi col. Fi 12 22 21 2 75,5 32,6 7,8 108,2 56,900 Wuxi col. Fi 13 22 21 2 52,7 52,7 74,600 Wuxi col. Fi 14 22 21 2 23,6 72,0 23,6 72,000 Wuxi col. S1 22 22 2 6,7 94,7 4,7 6,7 94,7 4,700 Wuxi col. (Fi+S)1 22 23 2 19,5 18,2 19,5 18,200 Wuxi col. Fr 1 22 25 2 5,9 5,0 7,5 10,8 7,7 5,9 12,5 10,8 10,000 SED/L1 Wuxi-CH 22 41 3 396,7 8 4,3 1,5 396,7 5,8 ,900 SED/L2 Wuxi-CH 22 41 3 4,8 1,1 6,0 1,4200 SED/L3 Wuxi-CH 22 41 3 1,2 1,2 5,100 SED/L4 Wuxi-CH 22 41 3 ,8 ,8 15,600 SED/FP1 Wuxi-CH 22 42 3 14,0 14,000 SED/FP2 Wuxi-CH 22 42 3 76,9 76,9 ,400 SED/FP3 Wuxi-CH 22 42 3 564,2 564,200 SED/FP4 Wuxi-CH 22 42 3 ,5 25,7 208,9 26,2 208,900 SED/FP5 Wuxi-CH 22 42 3 4,0 4,000 SED/FP6 Wuxi-CH 22 42 3 ,7 ,7 1,200 18 1 Eg 18-1,GD/00 23 1 1 6,0500 30,4200 36,6 29,7 58,3 2,0 1481,7 25,4 19,0 66,3 60,2 1507,2 175,600 18 2 Eg 18-2,GD/00 23 1 1 3,9220 18,8690 37,6 61,4 679,4 2805,6 64,3 16,9 99,0 679,4 2870,0 166,500 35 1 Eg 35-1,GD/00 23 1 1 4,1260 20,8560 33,2 81,1 91,1 4,9 2794,6 91,1 16,2 114,2 96,0 2885,8 272,600 35 2 Eg 35-2,GD/00 23 1 1 3,7330 19,9840 3,2 55,0 160,2 5,9 2585,3 42,2 14,7 58,3 166,0 2627,5 295,100 53 1 Eg 53-1,GD/00 23 1 1 4,1940 21,3930 8,0 80,6 63,6 60,0 2,9 3122,8 92,4 34,1 15,3 152,2 62,9 3249,3 355,300 53 2 Eg 53-2,GD/00 23 1 1 3,8510 20,8410 6,1 47,3 31,2 3,8 1728,9 29,0 26,6 53,4 35,0 1757,9 171,000 59 1 Eg 59-1,GD/00 23 1 1 6,0500 30,0940 4,2 21,0 51,6 72,3 6,0 2231,3 64,5 20,7 76,8 78,4 2295,7 210,100 59 2 Eg 59-2,GD/00 23 1 1 6,0310 29,4410 4,2 19,4 88,8 24,6 2389,3 78,4 23,2 23,7 113,4 2467,7 206,700 68 1 Eg 68-1,GD/00 23 1 1 5,1950 26,9030 10,3 21,6 95,2 27,7 2582,9 82,6 42,1 31,9 122,9 2665,5 192,600 68 2 Eg 68-2,GD/00 23 1 1 5,8590 29,6400 60,0 130,7 64,5 39,3 7045,4 161,9 107,5 33,2 190,8 103,8 7314,8 537,100 220 1 Eg 220-1,GD/00 23 1 1 4,6400 23,3200 8,9 10,0 13,2 8,6 1349,6 88,6 254,2 34,8 19,0 21,8 1692,4 82,900 220 2 Eg 220-2,GD/00 23 1 1 4,6500 23,5000 15,0 27,3 67,5 26,3 2,2 20,8 2720,0 228,0 60,7 109,8 49,3 2948,0 502,900 314 1 Eg 314-1,GD/00 23 1 1 4,3200 21,7800 5,1 9,5 17,0 3,2 1014,4 77,3 19,5 14,5 20,2 1091,7 159,200 314 2 Eg 314-2,GD/00 23 1 1 4,2300 22,9800 16,8 26,3 95,5 34,9 6,5 3,6 2390,6 143,1 473,0 57,2 138,6 45,0 3006,8 152,000 318 1 Eg 318-1,GD/00 23 1 1 3,9100 21,4600 11,2 57,8 86,6 43,1 20,8 2441,0 13,0 50,7 155,5 63,9 2454,0 533,500 318 2 Eg 318-2,GD/00 23 1 1 3,3300 19,1000 16,0 101,2 160,2 47,4 6,9 22,3 3282,3 12,1 13,8 64,8 277,3 76,6 3308,2 673,400 321 1 Eg 321-1,GD/00 23 1 1 4,9000 26,8900 6,8 127,8 72,8 14,7 7,7 16,5 5592,5 124,4 45,1 207,5 38,9 5716,9 409,600 321 2 Eg 321-2GD/00 23 1 1 4,5600 23,8100 4,9 47,8 58,3 62,5 6,0 2759,0 15,8 38,4 111,0 68,5 2774,8 86,700 323 1 Eg 323-1,GD/00 23 1 1 4,6100 24,0900 7,6 57,6 106,4 110,6 4,3 3,7 786,4 9,7 23,3 41,6 171,6 118,6 819,4 116,200 323 2 Eg 323-2,GD/00 23 1 1 4,8000 24,2500 4,9 31,6 240,3 2,7 628,1 8,2 99,8 39,3 36,6 243,0 736,0 80,900 SED-7 GD/00 23 41 3 ,400 SED-8 GD/00 23 41 3 1,4 1,4 ,500 SED-1 GD/00 23 42 300 SED-5 GD/00 23 42 3 ,8 ,6 1,4 ,800 SED-6 GD/00 23 42 3 8,0 8,000 SED-2 GD/00 23 47 3 ,4 ,4 3,0 ,8 3,0 ,900 SED-3 GD/00 23 47 3 ,600 SED-4 GD/00 23 47 3 ,700 SED-9 GD/00 23 47 3 ,900 SED-10 GD/00 23 47 3 ,9 1,8 2,7 ,500 SED-11 GD/00 23 47 3 ,5______________________________________________________________________________________________________________________________________________________________________________________________________________________________

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____________________________________________________________________________________________________________________________________Appendix D. List of samples collected in Pakistan (from Haleji in 1999, Karachi in 2000, Tounsa in 2000), and their content of organic contaminants (ppb, or ng/g on dry weight basis). other details as in App. C.

______________________________________________________________________________________________________________________________________________________________________________________________________________________________YEA NES EGG LAB LOC SPE TYP D_C F_C AHC GHC BHC DHC HEP HEX ALD AES BES PPDDE PPDDD PPDDT SHCB SHCH SCIC SDDT SPCB99 7 1 Eg/N7 E1 11 1 1 3.6199 18.8827 777.0 777.099 10 3 Eg/N10 E3 11 1 1 3.7779 19.7001 737.0 649.0 29.0 25.0 737.0 678.099 12 2 Eg/N12 E2 11 1 1 4.0296 19.4736 189.0 22.0 189.0 22.099 22 2 Eg/N22 E2 11 1 1 3.8265 21.1493 112.0 3163.0 14.0 112.0 3163.099 26 1 Eg/N26 E1 11 1 1 3.2424 18.8120 858.0 338.0 24.0 858.0 338.0 5.099 28 1 Eg/N28 E1 11 1 1 3.7240 22.0456 209.0 57.0 274.0 14.0 266.0 274.099 30 1 Eg/N30 E1 11 1 1 3.6093 19.1160 264.0 9982.0 264.0 9982.099 31 4 Eg/N31 E4 11 1 1 3.3191 18.4169 81.0 9.0 272.0 17.0 90.0 272.0 6.099 1 1 Ei/N1 E1 11 2 1 5.3216 26.9168 83.7 33.3 724.7 21.4 23.4 117.0 746.1 9.199 2 3 Ei/N2 E3 11 2 1 4.4280 24.1392 4.1 679.7 74.5 18.2 4.1 754.2 245.799 4 3 Ei/N4 E3 11 2 1 4.2659 22.3245 49.8 3.7 1726.8 51.5 18.2 21.4 49.8 3.7 1796.599 5 1 Ei/N5 E1 11 2 1 3.4586 14.4583 294.4 4.5 3102.8 29.9 182.2 14.6 298.9 3314.9 228.199 8 3 Ei/N8 E3 11 2 1 5.2386 27.6142 270.1 11986.8 66.2 270.1 12053.099 9 2 Ei/N9 E2 11 2 1 4.7996 24.3784 87.0 2859.8 21.8 87.0 2859.8 5.599 11 1 Ei/N11 E1 11 2 1 4.7857 23.1663 257.0 19.0 257.0 6.099 20 1 Ei/N20 E1 11 2 1 4.8892 24.9102 229.0 20.0 229.0 5.099 21 1 Ei/N21 E1 11 2 1 4.7164 24.0854 8.0 316.0 21.0 8.0 316.099 24 2 Ei/N24 E2 11 2 1 4.3514 26.3145 4.0 94.0 3567.0 163.0 43.0 21.0 98.0 3773.0 8.099 25 3 Ei/N25 E3 11 2 1 5.5356 25.7937 253.0 20.0 253.099 27 1 Ei/N27 E1 11 2 1 4.8618 24.0438 3.0 202.0 21.0 3.0 202.0 6.099 32 2 Ei/N32 E2 11 2 1 3.2815 17.8535 3863.0 64906.0 166.0 3863.0 65072.099 32 3 Ei/N32 E3 11 2 1 4.1267 18.8874 9359.0 136223.0 1108.0 311.0 9359.0 137331.099 33 2 Ei/N33 E2 11 2 1 3.7453 19.7319 4.0 655.0 20.0 4.0 655.0 5.099 34 4 Ei/N34 E4 11 2 1 4.3365 23.5425 8.0 251.0 16.0 8.0 251.0 6.099 35 4 Ei/N35 E4 11 2 1 4.5074 23.1802 47.0 608.0 15.0 47.0 608.0 12.099 40 1 Ei/N40 E1 11 2 1 5.1432 26.5568 153.0 20.0 173.0 26.099 41 1 Ei/N41 E1 11 2 1 4.0957 17.0780 37.0 15.0 1035.0 202.0 14.0 16.0 37.0 15.0 1251.0 5.099 42 2 Ei/N42 E2 11 2 1 4.0621 22.0430 2.0 183.0 358.0 22.0 12.0 185.0 380.0 6.099 43 1 Ei/N43 E1 11 2 1 3.5344 19.8777 2.0 163.0 28.0 14.0 2.0 191.0 45.099 43 2 Ei/N43 E2 11 2 1 3.5819 19.4869 234.0 25.0 18.0 259.0 35.099 9 C1N2 11 6 1 2.5464 16.1024 132.0 132.099 9 C2N2 11 6 1 2.5647 15.2346 13.0 207.0 16.0 13.0 207.0 11.099 9 C3N2 11 6 1 2.4217 15.0663 10.0 206.0 15.0 19.0 10.0 221.0 22.099 9 C4N2 11 6 1 2.5479 15.9910 14.0 234.0 10.0 18.0 14.0 244.099 PREY 2 - Oreochromis 11 21 2 .5791 3.4117 149.3 5.6 149.399 PREY 3 - Oreochromis 11 21 2 .4898 3.351899 PREY 4 - Oreochromis 11 21 2 1.5325 8.3633 10.5 36.8 10.599 PREY 5 - Oreochromis 11 21 2 1.6106 8.6285 21.3 3.8 21.399 PREY 6 - Oreochromis 11 21 2 .6305 3.3312 33.5 1.8 33.599 PREY 7 - Barbus 11 21 2 1.5373 7.6788 11.6 4.7 11.699 PREY 8 - Glossogobiu 11 21 2 1.4202 5.4343 5.499 PREY 9 - Glossogobiu 11 21 2 .7732 3.2941 32.999 PREY 10 - Glossogobi 11 21 2 2.5968 11.5862 35.299 PREY 11 - Glossogobi 11 21 2 1.7272 7.904299 PREY 12 - Glossogobi 11 21 2 2.0190 9.3381 8.2 15.7 11.8 31.3 8.2 27.599 PREY 13 - Glossogobi 11 21 2 .6147 2.7931 59.799 PREY 16 - Colisa 11 21 2 1.0701 4.3766 12.7 12.8 10.0 25.699 PREY 17 - Colisa 11 21 2 .8967 3.6083 7.6 5.3 7.6 1.599 PREY 18 - Colisa 11 21 2 1.1740 4.6638 4.9 16.9 4.7 21.8 5.799 PREY 19 - Barbus 11 21 2 1.5801 6.2967 .7 2.0 13.8 35.2 .7 15.899 PREY (1 + 14) - Carr 11 22 2 .3026 5.9460 16.6 5.6 16.6 10.6

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99 PREY 15 - Carridean 11 22 2 .3805 2.7981 5.799 SD 1 11 48 3 10.3 11.9 22.299 SD 2 11 48 3 1.0 1.1 1.099 SD 3 11 48 3 1.499 SD 4 11 48 399 SD 5 11 48 3 1.4 1.499 SD 6 11 48 399 SD 7 11 48 3 1.799 SD 8 11 48 3 1.299 SD 9 11 48 3 9.4 1.7 .4 11.199 SD 10 11 48 3 1.600 2 9 Eg 2 TB-Pak 12 1 1 3.5950 17.1640 7.7 13.5 37.2 1151.9 9.4 102.2 21.2 37.2 1263.5 34.800 17 9 Eg 17 TB-Pak 12 1 1 3.9440 18.2780 185.0 100.9 5.5 2890.0 35.0 518.4 185.0 106.4 3443.3 64.900 18 9 Eg 18 TB-Pak 12 1 1 4.3110 21.7400 4.2 113.9 428.6 332.7 15982.3 4101.9 1108.4 2.1 118.1 761.3 21192.6 665.000 29 9 Eg 29 TB-Pak 12 1 1 3.8900 19.2780 9.7 105.3 87.5 5.7 798.1 16.0 3.1 115.1 93.3 814.1 67.600 6 9 Bi 6 TB-Pak 12 4 1 4.2030 18.3260 10.4 11.4 35.8 320.8 21.8 35.8 320.8 46.900 14 9 Bi 14 TB-Pak 12 4 1 5.4890 24.3060 5.3 17.3 6.1 300.8 2.0 22.6 6.1 300.8 10.000 21 9 Bi 21 TB-Pak 12 4 1 4.3060 19.6750 6.1 22.6 58.6 321.1 28.7 58.6 321.1 13.100 23 9 Bi 23 TB-Pak 12 4 1 3.5690 18.9370 10.6 .7 96.3 216.3 11.2 96.3 216.3 11.800 25 9 Bi 25 TB-Pak 12 4 1 4.1110 21.6270 16.4 181.4 8.0 5.0 246.6 12255.7 3302.9 4.6 197.8 259.6 15558.6 1357.400 30 1 Bi 30a TB-Pak 12 4 1 4.8240 22.9730 9.8 .9 4.5 2.8 113.0 10.7 7.3 113.0 5.700 30 2 Bi 30b TB-Pak 12 4 1 4.6790 23.2730 6.9 5.0 84.5 3.9 173.2 2.8 11.9 88.4 173.2 6.200 31 9 Bi 31 TB-Pak 12 4 1 4.4860 20.8950 5.9 5.1 68.5 181.9 11.0 68.5 181.9 12.100 35 9 Bi 35 TB-Pak 12 4 1 3.7390 21.8000 162.1 162.100 54 9 Bi 54 TB-Pak 12 4 1 4.0750 21.9030 9.3 12.6 15.1 3.3 136.7 3.6 22.0 18.4 136.7 25.700 Prey/TFI TB-Pak 12 21 2 69.3 9.1 78.4 7.400 Prey/TFR TB-Pak 12 25 2 61.9 8.4 61.9 8.4 6.500 Prey/TMO TB-Pak 12 26 2 6.000 Prey/TIN TB-Pak 12 27 2 10.6 10.6 9.000 Prey/TCR TB-Pak 12 29 2 2.8 12.6 2.8 12.6 6.800 SED/P1 TB-Pak 12 43 3 67.7 67.7 .600 SED/P2 TB-Pak 12 43 3 7.4 7.4 .500 SED/P3 TB-Pak 12 43 3 .7 .7 .900 SED/RF1 TB-Pak 12 44 3 10.3 10.300 SED/RF2 TB-Pak 12 44 3 .500 SED/RF3 TB-Pak 12 44 3 5.9 5.900 SED/C1 TB-Pak 12 45 3 .700 SED/C2 TB-Pak 12 45 3 .300 SED/C3 TB-Pak 12 45 3 1.3 1.3 .800 1 1 Egu 1A KGB-Pak 13 3 1 5.9600 23.9300 19.0 24.2 46.0 36.8 1797.4 199.4 13.3 43.2 82.7 1996.8 2994.300 1 2 Egu 1B KGB-Pak 13 3 1 3.9400 21.6900 5.3 14.6 14.5 5.4 1420.2 4.4 19.9 19.9 1420.2 2196.800 2 1 Egu 2A KGB-Pak 13 3 1 4.3000 20.2600 11.5 1593.4 64.4 58.9 11.5 1657.8 2636.600 2 2 Egu 2B KGB-Pak 13 3 1 3.5000 13.3800 11.6 13.0 121.4 9.4 1755.7 142.4 3.8 24.5 130.7 1898.1 3170.900 5 1 Egu 5A KGB-Pak 13 3 1 3.8000 19.7800 16.1 18.2 76.5 71.9 1863.2 373.0 10.1 34.3 148.4 2236.2 2988.200 5 2 Egu 5B KGB-Pak 13 3 1 3.2700 18.1700 13.9 21.2 30.4 64.2 1785.4 298.6 12.0 35.1 94.5 2084.0 3484.200 9 1 Egu 9A KGB-Pak 13 3 1 5.1000 24.0700 10.2 15.3 71.6 19.7 1929.1 244.1 12.6 25.5 91.3 2173.2 6184.800 9 2 Egu 9B KGB-Pak 13 3 1 4.3100 22.4700 12.0 22.1 40.7 31.6 2139.4 417.4 16.6 34.1 72.3 2556.8 7321.500 21 1 Egu 21A KGB-Pak 13 3 1 4.8400 24.9700 10.4 47.5 100.5 9.0 63.5 3401.7 431.7 14.4 58.0 173.0 3833.4 6977.400 21 2 Egu 21B KGB-Pak 13 3 1 3.9900 21.4300 6.5 29.3 74.2 14.2 11.6 2728.7 328.1 8.1 35.7 99.9 3056.9 4515.100 50 1 Egu 50A KGB-Pak 13 3 1 3.6200 19.5500 16.3 35.9 131.8 7.8 52.9 745.5 3780.9 467.0 11.9 52.1 938.0 4247.9 6239.900 50 2 Egu 50B KGB-Pak 13 3 1 3.9400 21.6900 10.1 86.0 17.1 20.0 228.2 31.6 101.8 10.1 123.1 361.6 64.500 53 1 Egu 53A KGB-Pak 13 3 1 4.9700 25.9100 38.6 37.7 78.6 106.4 3347.0 591.2 76.3 185.0 3938.1 5764.700 53 2 Egu 53B KGB-Pak 13 3 1 4.4300 24.5400 10.2 27.8 58.9 18.2 2644.0 495.5 10.2 38.0 77.1 3139.5 4548.500 54 1 Egu 54A KGB-Pak 13 3 1 4.1700 20.2500 17.4 20.6 99.6 38.5 2465.9 378.5 21.7 38.0 138.1 2844.5 5646.500 54 2 Egu 54B KGB-Pak 13 3 1 4.6000 21.8000 8.4 11.7 19.9 21.2 2078.9 269.1 8.9 20.1 41.0 2348.0 4764.800 56 1 Egu 56A KGB-Pak 13 3 1 4.8400 23.9200 53.9 72.3 131.9 35.5 19.6 4695.0 472.0 126.2 187.0 5167.0 8277.000 56 2 Egu 56B KGB-Pak 13 3 1 4.8800 24.7600 14.1 59.0 85.6 32.9 13.2 5162.2 336.5 26.6 73.1 131.7 5498.6 8440.800 57 1 Egu 57A KGB-Pak 13 3 1 5.0000 26.3900 33.5 23.2 14.3 63.0 1887.9 180.8 56.7 77.3 2068.7 3617.300 57 2 Egu 57B KGB-Pak 13 3 1 4.9500 25.9900 14.4 15.9 60.7 18.5 1473.8 263.2 16.8 30.3 79.2 1737.0 2321.7

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00 58 1 Egu 58A KGB-Pak 13 3 1 4.7300 23.0500 5.8 33.8 105.8 11.1 3072.5 5.3 39.6 116.9 3072.5 4643.700 58 2 Egu 58B KGB-Pak 13 3 1 4.2600 21.1100 14.9 28.6 92.8 9.0 438.6 2676.5 245.2 8.8 43.5 540.4 2921.7 3138.400 59 1 Egu 59A KGB-Pak 13 3 1 3.6700 17.9700 7.1 830.7 13.0 717.7 3407.2 548.6 6.7 837.8 730.6 3955.8 7331.600 59 2 Egu 59B KGB-Pak 13 3 1 4.0300 19.0200 22.3 33.5 101.4 11.3 17.7 4002.6 587.2 23.7 55.8 130.4 4589.8 8763.400 61 1 Egu 61A KGB-Pak 13 3 1 3.4200 20.3600 21.6 83.8 3399.7 208.1 21.6 83.8 3607.8 3993.900 61 2 Egu 61B KGB-Pak 13 3 1 3.6300 21.0500 20.4 6.9 176.2 18.8 49.8 719.5 3569.4 473.1 12.6 27.4 964.2 4042.5 5613.200 62 1 Egu 62A KGB-Pak 13 3 1 4.5900 21.4600 25.7 20.3 57.3 25.5 1009.2 272.5 46.1 82.8 1281.7 1482.800 62 2 Egu 62B KGB-Pak 13 3 1 7.5300 23.9000 41.5 36.5 83.0 15.9 316.7 1482.5 487.0 78.0 415.6 1969.5 2117.300 Prey/F1 KGB-Pak 13 21 2 231.2 11.1 21.5 231.2 32.6 6.600 Prey/F2 KGB-Pak 13 21 2 146.2 9.3 20.3 146.2 29.6 6.400 Prey/F3 KGB-Pak 13 21 2 349.5 10.0 24.4 349.5 34.4 4.500 SED/OC1 KGB-Pak 13 45 3 1.4 2.0 5.5 1.4 7.5 .600 SED/OC2 KGB-Pak 13 45 3 .9 2.7 3.6 .500 SED/OC3 KGB-Pak 13 45 3 .800 SED/CK1 KGB-Pak 13 45 3 .4 .4 1.900 SED/CK2 KGB-Pak 13 45 300 SED/CK3 KGB-Pak 13 45 300 SED/GB1 KGB-Pak 13 46 3 1.3 6.9 19.3 1.3 26.3 4.300 SED/GB2 KGB-Pak 13 46 3 1.1 22.7 85.1 19.7 1.1 127.4 63.400 SED/GB3 KGB-Pak 13 46 3 1.3 4.5 5.7______________________________________________________________________________________________________________________________________________________________________________________________________________________________

148