distribution of heavy metals in periyar river and...

TOXICITY DUE TO COPPER AND ZINC ON THE FRESHWATER FISH, PUNTIUS PARRAAH (DAY, 1865) 48

3.1 INTRODUCTION AND REVIEW OF LITERATURE

The impact of heavy metals on aquatic systems has been extensively studied concerning a

wide variety of topics, especially during the last decade. Trace metals are natural elements in

aquatic ecosystems, but deposits of anthropogenic origin have caused a progressive increase in

their concentration, creating environmental problems in coastal zones, lakes, and rivers. In most

cases, the source has been untreated industrial and sewage deposits. The concentration of these

elements above tolerable levels is a disturbance factor for species survival and ecosystem stability.

Among the various toxic pollutants, heavy metals are particularly severe in their action due to

tendency of bio-magnification in the food chain.

Metal ions can be incorporated into food chains and concentrated in aquatic organisms to a

level that affects their physiological state. Heavy metals are high priority pollutants because of

their relatively high toxic and persistent nature in the environment. There are principally three

reservoirs of metals in the aquatic environment: water, sediment and biota. Metal levels in each

of these three reservoirs are dominated by a complex dynamic equilibrium governed by various

physical, chemical and biological factors. Among these three reservoirs the sediment is the major

repository for metals, in some cases, holding over 99% of the total amount of metal present in

the system. The study of river sediment is a valuable method of studying environmental pollution

with heavy metals (Tang et al., 2010). Rivers play major roles to the community especially in the

fishing industry and a source of water supply for people residing within the vicinity of the area.

River contamination either directly or indirectly will affect humans as a final consumer. Although

some of the heavy metals are required as micronutrients, it can be toxic when present higher than

the minimum requirements. Heavy metals have been introduced into rivers through geological

origin (Kaushik et al., 2009) and factory waste outlet point discharge. Therefore, knowledge of

CHAPTERCHAPTERCHAPTERCHAPTERCHAPTER 3 3 3 3 3

DISTRIBUTION OF HEAVY METALS IN

PERIYAR RIVER AND BIOACCUMULATION

OF COPPER AND ZINC IN PUNTIUS PARRAH


the changing concentration and distribution of heavy metals and their compounds in various

compartments of the environment is a priority for good environmental management programmes

all over the world (Don pedro et al., 2004). Heavy metals have drastic environmental impact on

all organisms. Heavy metals, such as copper, zinc, manganese, iron and cobalt, are essential

nutrients, having various physiological and biochemical role in the life processes of all aquatic

plants and animals; therefore, they are essential in the aquatic environment in trace amounts

(Samir et al., 2008). However, most of them are widely recognized as being very toxic at relatively

high concentrations, leading to various stress conditions manifested by different sublethal responses

or even death (Soegianto et al., 1999). Sublethal concentrations may seriously affect the

physiological and behavioural performance of organisms (Bridges, 2000). Copper, for example,

is a strong inhibitor of carbonic anhydrase activity in crabs (Vitale et al., 1999), also causing

cellular hyperplasia, vacuolization, and necrosis in the gill lamellae (Nonnotte et al., 1993). Zinc

has been described as affecting gas exchange and cardiac rhythm in fish, whereas embryonic

abnormalities have been noted in horseshoe crabs exposed to this metal (Itow et al., 1998).

The global heavy metal pollution of water is a major environmental problem. Due to this

reason the preservation and maintenance of our natural water resources is a very difficult task.

Rivers play a major role in assimilating or carrying of industrial and municipal waste water, runoff

from agricultural fields, roadways and street which are responsible for river pollution. Among

various organic and inorganic water pollutants, metal ions are toxic, dangerous and harmful because

of their tissue degradation in nature. Toxic metals are also bio accumulative and relatively stable

as well as carcinogenic and require close monitoring. Most of the rivers are deteriorating in

quality gradually and the maintenance of the quality of the river water will be a severe problem in

the years to come. Milenkovic et al. (2005) have studied the heavy metal pollution in sediments

from Danube River, Serbia and they observed higher concentration of Ni, Zn, Cu, Cr and Pb that

indicate the risk to the ecosystem. It has been recognized that aquatic sediments absorb persistent

and toxic chemicals to levels many times higher than the water column concentration (Casper et

al., 2004; Linnik and Zubenko, 2000). Charkhabi et al. (2008) have studied land use effects on

heavy metal pollution of river sediments in Guilan in Iran and they found higher concentration of

Mn, Fe, Cu, Pb, Zn and Cr in sediment samples. The embanked floodplains of the lower Rhine

River in the Netherlands contain large amounts of heavy metals, which is a result of many years of

deposition of contaminated overbank sediments (Middelkoop, 2000). Davies et al. (2006)

reported in their studies on bioaccumulation of heavy metals in water, sediment and periwinkle

Chapter -3Distribution of Heavy Metals...


(Tympanotonus fuscatus var. radula) from Elechi Creek, Niger Delta, that the sediment

concentrated more heavy metals than the water, while periwinkles accumulated more of these

metals than the sediment. Sediment associated pollutants can influence the concentrations of

trace metals in both the water column and biota if they are desorbed or become available to

benthic organisms. One of the major problems that heavy metals cause with respect to their

effects on aquatic organisms is their long biological half life. Therefore, they are among the most

frequently monitored micropollutants, and reliable techniques have been established for their

extraction and quantification (Sandroni et al.,2003; McCready et al.,2003), since sediment

contamination by heavy metals in rivers and estuaries has become an issue of increasing

environmental concern. Oribhabor and Ogbeibu (2009) have studied concentration of heavy

metals in a Niger Delta mangrove creek in Nigeria and they found higher concentrations of Ca,

Mg, Fe, Zn, Pb, Cd, Cr, and Ni. Hossein et al. (2011) observed higher concentrations of Cr and

Zn in Gorganrud River in Iran. Several works on water quality have focused on the physicochemical

characteristics of waters (Waziri et al., 2009; Hati et al., 2008). Waziri and Ogugbuaja (2010)

have studied the interrelationships between physicochemical water pollution indicators such as

biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO),

total organic carbon (TOC), and total dissolved solids (TDS) of River Yobe in North Eastern

Nigeria.

In India, various works have determined the presence of toxic metals in Indian rivers. The

physicochemical parameters and heavy metal content of river Gomti, Lucknow (Sharma, 1998)

and the metal pollution of Ganga river at Moradabad (Trivedi, 2000) have been analyzed. It was

found that Gomti River, Lucknow was polluted with copper, zinc and chromium. Kar et al.

(2008) have done an assessment of heavy metal pollution in surface water of Ganga River in

West Bengal. In their study Fe, Mn, Zn, Ni, Cr and Pb were detected in more than 92% of the

96 samples, whereas Cd and Cu were detected only in 20 and 36 samples respectively. The

rivers of Kerala also have been increasingly polluted from the industrial and domestic waste and

from the pesticides and fertilizers used in agriculture. Industries discharge hazardous pollutants

like phosphates, sulphides, ammonia, fluorides, heavy metals and insecticides into the downstream

reaches of the rivers. It is estimated that, nearly 260 million liters of industrial effluents reach the

Periyar daily from Kochi industrial belt (Green Peace, 2003). Heavy metals may consistently

retain within the water bodies or may be taken up by organisms such as plankton, benthos or fish

and finally be transferred to humans. This is essential to understand the source of heavy metal

pollution for future environmental planning strategies. River bed sediments act as both carriers



and source of contamination in an aquatic environment; not only play an important role in river

water pollution but can also provide a record of river’s pollution history. Many studies were

carried out on the distribution and accumulation of heavy metals in sediment of rivers in other

world areas (Diagomanolin et al., 2004; Okonkwo and Mothiba 2005; Olivares-Rieumont et

al., 2005; Szalinska et al., 2006; Kaushik et al., 2009; Vasile et al., 2010; Tang et al., 2010).

3.2 HEAVY METAL CONTAMINATION IN PERIYAR RIVER

Periyar River , the longest river of Kerala state is considered to be the life line of

central Kerala. It originates from the Sivagiri peaks (1800m MSL) of Sundaramala in

Tamil Nadu. The total length is about 300Kms (244Kms in Kerala) with a catchment area

of 5396sq.kms (5284sq.kms in Kerala). The total annual flow is estimated to be 11607

cubic meters. Periyar has been performing a pivotal role in shaping the economic

prosperity of Kerala, as it helps in power generation , domestic waste supply, irrigation,

tourism, industrial production, collection of various inorganic resources and fisheries.

However, as in the case of many other inland water bodies, Periyar River is gradually

undergoing eco degradation throughout its course of flow due to various anthropogenic

stresses, which include indiscriminate deforestation, domestic- agricultural-industrial water

pollution, excessive exploitation of resources, large scale sand mining, various interferences in

the flow of water etc.

Angamaly to Kochi occupies the most industrialized zone of the Periyar River basin.

There are over 50 large and medium industries and over 2500 small scale industries in this

region. The southern branch of Marthandapuzha which cater to the needs of these

industries is estimated to have a lean water flow of 8200cum/sec, which the monsoon

flow is calculated as 150-250cum/sec . The industries located in Edayar – Eloor area

consumes about 189343cum per day water from the day and discharge about 75% as

used water along with large quantity of effluents and pollutants. The major type of these

industries are fertilizers, pesticides, chemicals and allied industries, petroleum refining and

heavy metal processing, radioactive mineral processing, rubber processing units, animal bone

processing units, battery manufacturers, mercury products, acid manufacturers, pigment and

latex producers etc. The wide spectra of pollutants that adversely affect the natural

environmental quality of water of the river include toxic and hazardous materials such as

heavy metals, phenolics, hydrocarbons, pesticides, radionucleides, ammonia, phosphates,

domestic and untreated waste water.



Preliminary report of the trace/heavy metal concentration in the pollution affected areas of

Periyar River was reported by Paul and Pillai (1976). According to their report higher

concentrations of trace elements in the downstream locations were observed than in the upstream

regions. Elevated concentrations of copper, zinc and cadmium near Binani Zinc and Travancore

Cochin Chemical Ltd (TCC) were some of the highlights of the data. Comparatively higher

concentration of Cu and Zn in bottom sediments was recorded and it was considered as one of

the reason for the absence of benthic fauna in the polluted zone of Periyar river. Rivers generally

harbour a variety of fishes. Improper discharge of sewage and industrial water is one of the

reasons for the pollution of water bodies. Stress caused by these wastes, have a variety of effects

on faunal and floral communities living therein which may result in either decrease in their number

severely or eliminating them altogether. There exists a correlation between the intensity of pollution

and organisms living therein. Pollution of water is several folds higher in Periyar River due to

influx of considerable quantity of liquid and solid wastes of industrial/domestic/urban origin (Maya

and Seralathan, 2005). The investigations of the fresh water fish fauna of Kerala was initially

reported from the works of Day (1865, 1878) and is thus continuing (Hora, 1942; Indira and

Ramadevi, 1981; Easa and Basha, 1996; Menon, 1999; Karmakar and Das, 2004). Chacko

(1948) enlisted the fishes of Periyar River. A similar study by Arun (1998) exposed the

disappearance of 16 species of fishes from the same aquatic system within a span of 50 years.

The disappeared species included eels, catfishes, goby and cyprinids. According to Arun (1998)

the presence of 56% of the endemic fishes of Kerala in Periyar lake and river system makes it a

unique and diverse icthyofaunal region in South India. High level accumulation of heavy metals

manganese, zinc, copper, mercury etc. in the sediments and water poise ample chance for their

bioaccumulation and magnification at various trophic levels consisting of fish and man at the apex.

The toxic effect of these trace metals is influenced by environmental factors such as

salinity, pH, water hardness and temperature (Forster and Whitman,1981). Muhamed and

Mukundan (2007) have studied the seasonal variations in water quality of four stations in the

Periyar and the result revealed that all the samples showed acidic pH, turbidity, low salinity

during monsoon and higher values of nitrate, sulphate and hardness were higher during the summer

months.

The industrial belt of Eloor in Kerala is one of the World’s top toxic hot spot,

responsible for Periyar river’s pollution. Hindustan Insecticides Limited (HIL) that has been

manufacturing pesticides at its Eloor plant is responsible for making the industrial village a

toxic hot spot. Several diseases like cancer, congenital, birth defects, bronchitis, asthma,



allergic dermatitis and stomach ulcers has been increasing in the local population. This

reveals that “A poisoned river means a dying population”.

This chapter discusses the distribution of selected heavy metals chromium, copper, manganese,

lead and zinc in water and sediment of different sites in Periyar River and also the bioaccumulation

trends of Cu and Zn at sublethal concentration in Puntius parrah.

3.3 MATERIALS AND METHODS

3.3.1 Study Area

River Periyar, the longest river of Kerala state, and is considered the life line of Central

Kerala (Anon, 1984). It originates from the Sivagiri peaks (1,800mMSL) of Sundaramala in

Tamil Nadu. The total length of the river is about 300 Kms (244Kms in Kerala) with a catchment

area of 5,396Kms (5,284Sq.Kms in Kerala). The total annual flow is estimated to be 11,607

cubic meters. During its journey to Lakshadweep Sea (Arabian Sea) at Cochin the river is enriched

with water from minor tributaries like Muthayar, Perunthuraiar, Chinnar, Cheruthony, Kattapanayar

and Edamalayar at different junctures. The temperature of the area varied from 25oC to 37oC

throughout the year. Mullayar join with Periyar at a point 50Km down its course from its origin

and the combined river then flows into the Periyar River. After crossing Vandiperiyar it further

flows downwards from Periyar lake, Perunthuralur and Kattappanaar joins Periyar and the swollen

river reaches the catchment area of Idukki. After this, Edamalayar joins Periyar and it covers the

present day, Edamalayar and Pooyamkutty Project areas and reaches the age old Periyar barrage.

Periyar thus flows from Malayattor to the holy Kalady. From Kalady it takes a twisted course to

Aluva through Chowara. At Aluva it splits into Mangalapuzha and Marthandavarmapuzha. After

parting ways at Aluva, Marthandavarmapuzha splits into two and thus joins again. At

Thaikkattukara it once again splits into two. The major branch flows through the industrial area

Eloor and other minor one through Manjummal. At Varapuzha both join the Lakshadweep Sea

(Fig.3.1).

Five study sites were identified in the river for the collection and analysis of the selected

trace metals in water and sediment samples on a seasonal basis (Plate 2) The details of each of

the study sites are described below.



Site I : Kuzhikundam Creek

Eloor is the most industrialized zone of the Periyar River. Many hazardous industrial effluents

released from the nearby factories seriously threaten Eloor, situated on the banks of Periyar

River. There are around 250 factories in this area, 125 of which are chemical factories, like

Binani Zinc, Travancore Cochin Chemicals Ltd, United Catalysts India Ltd, Kanyakumari Polymer.

These factories discharge effluent directly to the Kuzhikundam creek, a tributary to the Periyar

River (Plate 2.I).

Site II : Pathalam Bund

Pathalam is a suburban region of the city of Kochi, in the state of Kerala. It is situated

close to Eloor, the industrial district of Kochi. Pathalam bund represents the lower reaches of

Periyar River and is connected to a barrage at Chettuva in northern part of the backwater (Plate

2.II).

Site III : Chowara

Chowara represents the Periyar River boundary extending to about 4km length from Kalady.

About one thousand human settlements are seen on the river banks in this station. Very heavy

sand mining is seen here, and the water level is very low. There is one irrigation unit, Kerala water

authority, Chowara situated near the location besides a ferry service (Plate 2.III).

Site IV Kalady

Kalady situated 48 km north-east of Kochi, on the banks of Periyar River. Across the

Periyar River at Kalady is the Sree Sankaracharya bridge. Water from the river is drawn for the

purpose of irrigation as well as drinking. Small deltas have also been formed during recent years

in the river at Kalady due to the ruthless unauthorized sand mining. Small patches of islands have

also been formed at different areas of the river, which become more prominent during summer

(Plate 2.IV)

Site V Malayatoor

Malayatoor is situated near Kalady, a village in the North Eastern corner of Ernakulam

District. The name ‘Malayatoor’ is an amalgamation of three small words. Mala (Mountain) Aru

(River) Ooru (Place). This is to say, Malayatoor is a meeting place of mountain, river (Periyar),

and land. Kurisumudy is a mountain at Malayatoor, 1269’Ft above sea level.



Three samples each of water and sediment were collected from the five selected sites in the

Periyar River during the pre-monsoon period (2010). The physicochemical parameters, colour

and odour, temperature, pH, total dissolved solids (TDS), salinity, turbidity and conductivity of

the samples were also determined. The distribution of the metals chromium, copper, manganese,

lead and zinc in water and sediment samples were analysed for the study period.

3.3.2 Physicochemical parameters

The pH, total dissolved solids (TDS), salinity, temperature, turbidity, and

conductivity of water samples were measured using Systronic water analyzer No: 371

following standard procedures (APHA, 2005).

3.3.3 Water and Sediment samples

Water samples were collected in the early morning hours from 7.00 am to 9.00 am, using

Niskin water sampler. Samples were collected from just below the surface and for the column

(two meters below the surface), mixed to have a composite sample and stored in bottles for the

determination of heavy metals and physicochemical variables. On arrival, 100ml of sample

was transferred to a clean glass bottle and acidified with HNO3 (10%). Fifty millilitres of the

water sample was transferred to a 100ml boiling tube, placed onto the Gerhardt Kjeldatherm

digestion block, and refluxed at 1300c for 5 hrs. After cooling to ambient temperature, the

digests were filtered into volumetric flasks diluted with deionised water, made upto a

volume of 50ml and mixed (APHA, 2005).

Sediment samples were air dried until weighing readings become constant

(approximately 5 days). They were then crushed using a pestle and mortar until homogenous

and sieved through a 2mm mesh. A sample of 0.5g sediment was weighed into a glass of

100ml boiling tube and to this 10ml of deionised water was added, followed by 7.5ml

of concentrated hydrochloric acid and 2.5ml of concentrated nitric acid. Boiling tubes were

then placed into a Gerhardt Kjeldatherm digestion block (40space) connected to a Gerhardt

Turbosog scrubber unit (filled with 10% sodium hydroxide). The samples were then

refluxed at 130oC for 5hrs.

After cooling to ambient temperature, the digests were filtered into volumetric

flasks, diluted with deionised water, made upto a volume of 50ml and mixed. A standard

Reference Material, BCL-143 (trace elements in a sewage sludge amended soil), certified



by the commission of the European Communities, Brussels and a blank sample, were

prepared with the batch of the samples. All were prepared in 15% HCl acid 5% nitric acid.

Following preparation, samples were analyzed for the metals, chromium, copper, manganese,

lead and zinc by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer), using

a Varian Liberty–100 sequential spectrometer.Two multi - element instrument calibration standard

were prepared at a concentration of 10mg/l. One in an acid matrix of 5% HCl acid and

5% HNO3 (for solid samples), the other in an acid matrix of 10% HNO

3 (for aqueous

samples). Calibration were validated using quality control standards (8mg/l), prepared

internally from different reagent stocks. Samples exceeding the calibration range were diluted

accordingly, in duplicate and reanalyzed. The results were expressed in ìg/l (APHA, 2005).

3.3.4 Statistical Analysis

The data obtained for various parameters were statistically tested by analysis of variance

(ANOVA), using the SPSS version 16.0 software. The mean values of the results were tabulated

and graphically represented. The results obtained were also compared with the standards

(Appendix I).

3.4 RESULTS

Evaluation of the water quality in five selected sites of Periyar River was carried out during

the pre-monsoon (March, April and Mid-May 2010) season. The analysis of physicochemical

variables of water samples collected from the five selected sites of Periyar revealed that Site I

(Kuzhikundam creek) showed conspicuous significant differences in the various parameters

analyzed.

3.4.1 PHYSICAL PARAMETERS

Colour and odour

An unpleasant odour and colour change of water were noticed in the water samples collected

from Site I and II. The colour of the water samples collected from site I was oily black and it was

dark green in the samples collected from site II (Table 3.1). The water colour was natural in the

samples collected from site III, IV and V and there was no particular odour in these samples.

Temperature

Temperature is an important physical factor of any habitat and a significant variation was

observed in the Site I (Table 3.2). Mean water temperature in Site I was 360C, that in Site II was



340C. The fluctuation in temperature between Site I (Kuzhikundam Creek) and Site II (Pathalam

Bund) was statistically non-significant. The average temperature in Site III (Chowara) was 320C.

The difference between Site I and Site III was statistically significant at p<0.001. The temperature

in Site IV (Kalady) and Site V (Malayatoor) was 330C respectively (Fig 3.2). The difference

between Site I and these two sites was statistically significant at p<0.05.

3.4.2 CHEMICAL PARAMETERS

pH

The pH of water samples also exhibited variations with a significantly low value in Site I. The

water sample in Site V showed the highest pH value of 6.37 whereas it was 5.1 at Site I. In Site

II the average pH was 5.77 (Table 3.3). The pH of water samples collected in Sites III and IV

was 6.07 and 6.15 respectively (Fig. 3.3).

Total dissolved solids (TDS)

The presence of total dissolved solids (TDS) level showed a distinct pattern of variation in

the different sites with significant higher values in Site I (Table 3.4). Total dissolved solids in Site

I was 1.47mg/l. TDS in Site II and III was 0.195mg/l, 0.024mg/l respectively. In Site IV and V,

the TDS was 0.019mg/l and 0.023mg/l respectively. The difference between Site I and the all

the other four sites was statistically significant at p<0.001.

Salinity

Estimation of salinity in the various sites depicted a different pattern. The salinity in Site I

was high as compared to the other sites (Fig. 3.4). The salinity in Site I and II was 1.31mg/l and

0.17mg/l. The salinity in Site III, IV and V was not significant. The difference between Site I and

the other sites was statistically significant at p<0.001.

Turbidity

The turbidity values were significantly higher in Site I than that in the upstream sites III, IV

and V (Table 3.5). The difference between the turbidity value in Site I and other Sites was

statistically significant at p<0.001. The turbidity in Site I was 14 NTU, that at Site II, was

1.9NTU, and that at III, IV and V, it was 0.55NTU, 1.7NTU and 3.7 NTU respectively (Fig.

3.5).



Conductivity

In comparison to the other study Sites conductivity values were also higher in the Site I

(Table 3.6). The electrical conductivity of Periyar water fluctuated from 0.036µS to 28.7µS at

Site I to Site IV. In Site II, it was 4.0µS, whereas in Site III and IV, the electrical conductivity

was 0.05µS and 0.04µS respectively (Fig. 3.6).



3.4.3. Heavy Metals in Water



Trace metals in water samples from the five different sites of Periyar were analysed. The

results revealed that some of the heavy metals were present in high level; especially zinc, lead and

copper were in high concentration in Site I as compared to the other sites. The concentration of

heavy metals in Site I follow the trend: zinc>manganese >copper>lead>chromium. The zinc

concentration in Site I was 16.26µg/l; manganese, copper, lead and chromium was 2.99µg/l,

2.59µg/l, 2.06µg/l and 1.21µg/l respectively. In Site II concentration of heavy metals follows the

trend: zinc>copper>manganese>chromium>lead. Manganese was in the highest concentration

(5.32µg/l) in Site IV while all the other metals were in low concentration. The concentration of

heavy metals in water samples collected from Site III and Site IV followed the trend: zinc >

manganese > copper > lead > chromium and manganese > zinc > copper > chromium > lead

respectively. Copper, chromium and lead were below detection limit in water samples collected

from Site V. Zinc concentration in Site V was 0.785µg/l.

3.4.4. Heavy Metals in Sediments

Analysis of trace metals in sediment samples revealed that they were present in high

concentration, especially zinc and copper in Site I as compared to the other sites. The concentration

of heavy metals in Site I followed the trend: zinc>copper>lead> manganese>chromium. The

highest concentration of zinc in Site I was 19.855µg/g and copper was 4.32µg/g. In Site II,

heavy metal concentration followed the trend: zinc>copper>manganese>chromium>lead.

Manganese was in the highest concentration (6.18µg/g) in Site IV while all the other metals were

in low concentration. Copper, chromium and lead were below detection limit in sampling Site V.

Sediment samples at Site III and IV followed the trend: zinc>manganese>chromium>copper>lead

and manganese>zinc>chromium>lead> copper respectively.

3.5 DISCUSSION

Aquatic populations interact with the physicochemical and biological factors in their habitat.

Any change in the habitat can induce stress on the life forms. The major water bodies and rivers

in Kerala are not free from the pollution stress of varying degrees due to the influx of effluents

from nearby factories, pesticides and fertilizers from cultivating areas, besides urban and rural

sewages. Hence analyses of sediment and water quality of Periyar form a case study to highlight

the impact of pollution especially heavy metal pollution on fishes.

Periyar River is highly polluted due to the effluents released into the river from a

number of industries such as Fertilizers and Chemicals of Travancore Ltd (FACT), Travancore




Table 3.7 Trace Metals in water samples in the five study Sites of

monsoon period (March-May 2010)

Metal(µg/l) Site I Site II Site III Site IV

Chromium

1.205±0.005

0.195±0.005

0.065±0.005

0.105±0.005

Copper

2.59±0.090

1.47±0.05

0.075±0.025

0.225±0.175

Manganese

2.99±0.01

0.67±0.10

0.33±0.10

5.32±0.17

Lead

2.06±0.050

0.1±0.020

0.075±0.005

0.065±0.005

Zinc

16.26±0.250

2.19±0.10

1.02±0.01

0.565±0.055

Data are represented as mean±SD

BDL – Below detection limit


Cochin Chemical Ltd (TCC), Hindustan Insecticide Ltd (HIL) and Binani Zinc limited etc.

The water and sediment samples in Sites I and II (Kuzhikundam Creek and Pathalam bund)

showed highest variations since these are industrial areas. Analysis of the physicochemical

parameters of water samples revealed that Periyar River had a freshwater regime up to Site III

(Chowara) as observed by Jayapalan et al. (1976). The industrial effluents discharged from the

factories located downstream severely affected the aquatic biota.

Temperature is a prominent physical stressor. It exerts important influence on the immune

system of fish. Temperature stress particularly excessive hot temperatures are very detrimental

to fish, although the precise impact of sudden increase in temperature on the immune system is

not known (Wanger et al.,1997) . The observed data during the present study in Periyar River

ranged from 320C to 360C. Generally the highest value occurs during pre-monsoon period.

Many workers have noted higher water temperature at Kuzhikundam creek (Site I) near effluent

discharge point from FACT, TCC and Binani (Singh, 1981; Sharma and Pant, 1989; Bilgrami,

1990). Devi et al. (1979) also reported elevated temperature at the industrial discharge area of

Periyar River. According to them, it was partly due to the shallow nature and absence of strong

tidal influence in this region.

Saraladevi et al. (1979) noted elevated water temperature at areas of industrial discharge.

Sharma (1999), noted that rise in water temperature by few degrees due to the waste

materials and effluents in fresh water bodies. The waste are known to be thermally more

heated due to presence of different chemicals and microorganisms in the wastes in which

usually the exothermic reactions take place. All these observations support the results of this

study.

In the present study, pH of Periyar River water in the selected Study Sites (Kuzhikundum

creek, Pathalam bund, Chowara, Kalady and Malayatoor) ranged from 6.37 to 5.10. Water

samples collected from the industrial areas (Kuzhikundum creek and Pathalam bund) was acidic

with a pH of 5.10 and 5.77 compared to the samples collected from other non-industrialized

areas. Studies conducted by Paul and Pillai, (1976) in the same area reported a pH range of 5.1

to 9.5 which corroborate with the present study. Salinity in the industrial areas was higher than

the other sites of the river. This observation supports the study of Joseph et al. (1984) for the

same area of the river during the present study. According to them zero salinity was recorded

in Periyar River upto Alupuram and FACT area, during pre monsoon period with a

marginal increase in salinity in the Eloor area of the river. The substances that do not form a



part of true solution cause turbidity in water. The high turbidity of water in Site I may be due to

the presence of suspended materials that was brought into the water through the industrial

discharges. Turbidity hampers light penetration and affects the existence of primary producers

and other organisms. Water with high dissolved solids generally is of inferior palatability and

many induce an unfavourable physiological reaction in the transient consumer. In this study, the

higher value of TDS and conductivity in Kuzhikundam creek (Site I) are indicative of the presence

of industrial effluents in the water. Pollution has a direct relationship with the dissolved solids

(Verma et al. 1978; Prasad, 1980). The findings of the study on physicochemical parameters on

selected Study Sites of Periyar River denote the polluted nature of water in the river.

The results of heavy metal analysis in water and sediment revealed high concentration of Cr,

Cu, Mn, Pb and Zn in Site I. The results of this brief investigation give a strong indication

that activities of the industrial establishments, HIL, FACT, TCC and Binani Zinc plant in

Kochi, Kerala , have resulted in substantial contamination of the Kuzhikundam Creek and

adjoining areas of Kuzhikundam creek. Since Kalady, Chowara and Malayatoor are non industrial

areas they show very less concentration of heavy metals, whereas, some metals were below the

detection level in Malayatoor study area (Site V). Higher concentration of trace metals

( Meenakumari and Nair, 1996; Khurshid et al., 1998; Nair, 1997) have been reported from

Periyar water and Cochin backwater that also support the findings of the present study.

Jayapalan et al. (1976) explored some aspects of physicochemical and biological

variation of Periyar water due to the effluent discharge from the industrial complex, FACT.

Ramani et al.(1980) analyzed the chemical composition of sediments of Cochin backwaters

in relation to pollution. These works underlined the presence of heavy metals in high concentration

from the samples collected near the Eloor industrial estate, support this study. The results of

present study corroborates with the reports of Green Peace (2003), that the industrial belt of

Eloor which include Kuzhikundam Creek in Kerala is one of the world’s “top toxic hot

spots”. Based on the detailed studies on distribution and concentration of heavy metals in the

Periyar River and discussions, it was observed that, the concentration of heavy metals Cr, Cu,

Mn, Pb, and Zn was above the permissible limits of the U.S. Environmental protection

agency(USEPA) standards ,WHO Standards, and Bureau of Indian standards(BIS)(Table 3.9)



Table 3.9 Mean concentration of metals in Periyar River (Kuzhikundam creek) and

permissible standards.

Heavy metal Periyar(Kuzhikundum)(mg/L) W H O ( W H O

guidelines)(mg/L) USEPA(mg/L) BIS(IS 10500:1991)(mg/L)

Since trace metal ions are extremely toxic, the consumption of river water polluted

with heavy metals may cause serious health problems. Kuzhikundam Creek is highly

polluted, due to heavy industrial discharges. This Creek, receives the industrial discharges which

further reaches the Periyar River with all these industrial discharges. Thus it deteriorates the

quality of river water thus affecting the aquatic fauna and flora.

However detailed studies on the trace metal distribution and its dynamics for longer

sampling periods for different regions of the Periyar River would help us to understand further

more on the definite pollution and associated problems in the water body. The data evolved

through the present study would provide some indicative trend for future studies.

3.6 BIOACCUMULATION OF COPPER AND ZINC IN P. PARRAH

Concepts such as biomagnification, bioaccumulation, biotransference or concentration factors

convey little information about the real threat originating from heavy metals in an aquatic food

chain. In polluted aquatic ecosystem the transfer of metals through food chains can be high

enough to bring about harmful concentrations in the tissues of fish (Dallinger et al., 1987). In

order to describe the transfer of heavy metals through aquatic food chains terms like

“biomagnification”, “bioaccumulation”, or “concentration factors”, has been introduced.

Biomagnification means that metals are progressively concentrated within a given food chain,

metal levels increasing with the order of the trophic level. Biotransference is defined as the relative

enrichment of heavy metals through successive links of food chains. Bioaccumulation means that

heavy metals in organisms are concentrated in relation to abiotic environmental levels, such as



those of water or sediment. Concentration factors indicate how many times a fish concentrates a

metal above a certain environmental level which is usually that of water. Similarly, biotransference

factors express the concentration of a metal in an organism in relation to the next lower trophic

level. Knowing the concentration of contaminants in a particular species or trophic level tells very

little about the consequences of exposure. Hence the food web models have to relate predicted

tissue concentrations to ecologically significant effects (Cain et al., 2004; Toll et al., 2005).

It has been found that, both bioconcentration and biotransference factors can increase along

a given food chain upto the level of the organisms on which the fish species feed (Heyraud and

Cherry, 1979). The transfer of heavy metals through food chains remains an important issue in

metal assimilation by fish. Most heavy metals are effective at very low concentrations, so even

low assimilation rates are sufficient to attain biologically significant or harmful concentration in

tissues (Jackim et al., 1970; Murai et al., 1981; Segner and Back, 1985). During all contamination

processes in fish, heavy metals cross biological barriers, the gill epithelium and skin for direct

route and the wall of digestive tract for indirect route (Lloyd, 1992) and accumulate mainly in

metabolically active tissues such as the kidney, liver and gills. Fish are often at the top of the

aquatic food chain and may concentrate large amounts of some metals, this metal accumulate in

fish organs and can cause many disturbances in its vital processes (Gomaa et al., 1995).

Many fish species are among the top consumers of trophic pyramids in aquatic ecosystem.

In consequence, they are endangered by diet borne pollutants transferred along the food chain

(Sarkka et al., 1978; Moriarithy, 1984). Although food chain transfer of most metals is most

probably a less serious issue than for lipophilic organic contaminants, dietary exposure should

not be ignored when assessing ecological risk of heavy metals (Hansen et al., 2004). The

accumulation of heavy metals depends on uptake through contaminated food and via water, but

the relative importance of these two avenues for metal uptake often remains uncertain. Moreover,

the possibility has to be considered that in many aquatic ecosystems the bioavailability of heavy

metals may have changed during the past years due to increasing efforts in waste water treatment

(Jernelov and Lann, 1971) or because of the establishment of strict environmental standards and

laws which regulate emissions (Czarnezki, 1985). As a consequence, the greater part of heavy

metals may now be contained in particulate fractions because of the decreased concentrations of

water borne ionic compounds. The situation may lead to elevated concentrations of heavy metals

in benthic animals and in plants (McIntosh et al., 1978; Tessier et al., 1984).



Biomagnification of pollutants is a well known phenomenon, especially with respect to some

organic compounds, like organochlorines or polychlorinated biphenyls (Jarvinen et al., 1977;

Paasivirta et al., 1983; Passivirta et al., 1985; Newman and Clement, 2008). For heavy metals,

however, this assumption is the subject of conflicting arguments, and, as stated by Ferard et al.,

(1983), the term biomagnification has often been misused. Nevertheless, tissues of many fish

species contain elevated metal concentrations exceeding the nationally or internationally agreed

quality standards for fish meat (Nabrzyski 1975; Phillips et al., 1980; Czarnezki, 1985; Dallinger

and Kautzky, 1985a).

In aquatic systems the accumulation of a metal to organisms depends on many physicochemical

as well as biological factors. Availability is influenced, for instance, by the chemical speciation of

ionic metal forms, the chemistry of water and relative distribution of metals between soluble and

particulate fractions. The speciation of a metal in aqueous solution depends on the number and

properties of ionic species and binding states. Basic problems of metal speciation in seawater

have been discussed by Millero (1977) and Kester et al. (1986). It has been shown, moreover

that the uptake as well as the toxicity of heavy metals may substantially depend on the chemical

species involved (Sunda et al., 1978; Czuba and Mortimer, 1980; Van der Putte et al., 1981;

Borgmann, 1983; Mills, 1986; Piscator, 1986).

The chemistry of water itself influences the speciation of heavy metals in both marine and

limnic environments. Factors such as hydrogen ion activity (Hakanson, 1980; Bacini and Suter,

1979) hardness (Kinkade and Erman, 1975; Bell, 1976; McCarthy et al., 1978; Calamari et

al., 1980) and salinity (Somero et al., 1977) are reported to be crucial in this respect. Furthermore,

the presence of organic compounds and suspended particles may change the activity of free

metal ions (Gachter and Davis, 1978; Hirose and Sugimura, 1985; Bernhard and George, 1986).

Binding to, and releasing from sediment (Gardiner 1974; Patric et al.,1977; Sakata, 1985) also

affects the availability of metals to aquatic life (Tessier et al., 1984; McCloskey et al., 1998), as

do biological or chemical transformations, such as the methylation of mercury (Jensen and Jernelov,

1969).

Among the biological factors affecting metal availability, species specific differences like

feeding behaviour (Van Hassel et al., 1980; Czarnezki, 1985; Loring and Prosi, 1986; Clewell

and Gearhart, 2002) and habitat preferences (Ney and Van Hassel, 1983; Czub and McLachlan,

2004) play a dominant role. These basic features are modified by physiological factors, such as

accumulation rates and the binding capacity in an animal (Jeng and Sun, 1981; Newman and



Unger, 2003), as well as by ecological influences like temperature (Somero et al., 1977; Edgren

and Notter, 1980) and feeding habits (Mathers and Johansen, 1985). As a consequence, the

pathways of metal flux into aquatic organisms depend on specific features of water chemistry,

sediments and on the biological characteristics of the organisms. As far as fish are concerned,

there are three possible ways by which metals may enter the body: the body surface, the gills and

the alimentary tract.

Little is known on the uptake of heavy metals through the skin. According to Morsey and

Protasowiki (1990) cadmium causes pathological alterations in the gill filaments and respiratory

lamellae, hepatopancreas and kidney of Cyprinus carpio. There are some indications that mucus

secretion may prevent heavy metals from entering the body of fish (Varanasi and Markey, 1978;

Lock and Van Overbeeke, 1981; Eddy and Fraser, 1982; Part and Lock, 1983). The assumption

is that the skin does not play a dominant role in the uptake of heavy metals is not true for the gills.

They are not only the main organs of gas exchange, but, as a highly specialized and exposed part

of the body surface, also represent an important site of uptake of essential and non essential

metal ions from the water (Fenwick and So, 1974).

For instance, after exposure of fish to soluble zinc or cadmium these metals are found in

their gills (Hughes and Flos, 1978; Westernhagen et al., 1978). It has been shown by Part and

Svanberg (1981) that cadmium is taken up by perfuse gills of rainbow trout, a significant uptake

occurring immediately after exposure (Anderson and Spear1980; Collvin, 1984; Segner, 1987).

From the gills, the absorbed metals are distributed throughout the whole body and accumulate in

specific organs. Heavy metals have also been reported to induce harmful changes in gill morphology

(Van der Putte et al., 1981; Karlsson-Norrgren et al., 1985). It thus seems, that passage through

the gills is an important pathway for the soluble fractions of heavy metals into fish. Because the

gills are intimately associated with ionic regulation it is predictable that heavy metals will influence

aspects of osmotic and ionic regulation in fish. With relatively high levels of Zn2+(40ppm) rainbow

trout die mainly through tissue hypoxia found little change in the arterial blood plasma osmotic

pressure or ionic content (Skidmore, 1970 ; Burton et al., 1972) a major factor being disruption

of the brachial respiratory epithelium (Skidmore and Tovell, 1972). Gills are the first target of

water borne pollutants due to the constant interaction with the external environment, as well as

the main place for copper uptake (Campbell et al., 1999). It is well known that changes in fish

gill are among the most commonly recognized responses to environmental pollutants (Mallat,

1985).



The liver, the largest mass of glandular tissue in the body is unique among organs in addition

to a supply of arterial blood from the hepatic artery; it also receives a major supply of blood from

veins from the digestive system, pancreas, and spleen via the hepatic portal vein. The liver is

therefore situated directly in the way of blood vessels that convey substances absorbed from the

digestive system. The position gives the liver the first chance to metabolize these substances and

it is also the first organ to be exposed to toxic compounds that have been ingested. The liver has

the ability to degrade toxic compounds, but can be overwhelmed by elevated levels of these

compounds and can subsequently be damaged (Ross et al., 1989). The liver can be regarded as

the body’s detoxification organ and hence a target organ of various xenobiotic substances. After

contamination with copper or cadmium, high metal contents are found in liver and kidney (Edgren

and Notter, 1980; Dallinger and Kautzky, 1985b). Since these organs are targets for final deposition

of various heavy metals, the levels in both organs seem to be independent of the pathway of

uptake. The fish muscle has been known as water exchange tissue with blood.

The significance of bioaccumulation studies lies in the potential disruption of ecological balance

which had been attained over the years and the public health risk which may occur when organisms

including man, which occupy higher levels in the food chain, feed on highly contaminated prey

and become exposed to the toxic effects of the metals. Real life tragic experiences such as the

Minamata and Itai-Itai diseases have shown to the whole world the devasting effects that the

accumulation of heavy metals in animal/plant tissues which serve as food sources could have on

higher predators, particularly man (Varma et al., 1976). Furthermore, the observation of very

high concentrations of heavy metals in and animal/plant tissues inhabiting water bodies with low

metal concentration in their sediment and water column have necessitated the inclusion of such

bioaccumulators in monitoring programmes aimed at establishing the environmental levels of such

pollutants in aquatic ecosystems (Bryan and Langston, 1992). Therefore, studies on

bioaccumulation of heavy metals, particularly in organisms that serve as food for man, have been

a focus of many research efforts all over the world (Kiffney and Clement, 1993; Van-Den-

Heever and Frey, 1994; Oyewo, 1998; Waqar 2006; Adami et al., 2002; Rasmussen and

Anderson, 2000; Aucoin et al., 1999). The organisms developed a protective defense against

the deleterious effects of essential and non essential heavy metals and other xenobiotics that

produce degenerative changes like oxidative stress in the body (Abou EL-Naga et al., 2005;

Filipovic and Raspor, 2003).



Therefore in view of this, study on the bioaccumulation of copper and zinc in gills, liver,

kidney and muscle tissues of commercially edible fresh water fish Puntius parrah was done

under sublethal condition.

3.7 MATERIALS AND METHODS

The general methodology, collection of specimens, acclimation, preparation of test solution

and other experimental protocols have already been described in Chapter 2. Fishes were divided

into two groups, with one group serving as control and the other as exposed to sublethal

concentration of 0.06mg/L copper and 0.9mg/L zinc for 28 days. Five specimens of the control

and five specimens of the metal exposed group were sacrificed during each exposure period of

1, 3,7,14 and 28 days.

Fish from each group were dissected to separate organs (gills, liver, kidney and muscles).

The separated organs were put in Petri dishes to dry at 1200C until reaching a constant weight.

The separated organs were placed into digestion flasks and ultra pure concentration nitric acid

and perchloric acid (3:1) were added. The digestion flasks were then heated until all the materials

were dissolved. The extract was diluted with double distilled water appropriately to make a 50ml

solution. The elements copper and zinc was assayed using Shimadzu AA 6200 atomic absorption

spectrophotometer and the results were given as µg/g dry weight (dw) (APHA, 2005).

3.7.1 Statistical Analysis

Data obtained was subjected to statistical analysis for t-test and ANOVA using SPSS

16.0, version software to determine the significance of the results.

3.8 RESULTS

The heavy metals, zinc and copper were analysed in different organs like gills, liver, kidney

and muscle of the experimental fish (Table 3.10-3.17). Copper in gill ranged from 1.32µg/g to

10.46µg/g and zinc from 20.1µg/g to 243.38µg/g.dw during the initial to 28 days of exposure.

The copper accumulated in liver ranged from16.636µg/g to 78.842µg/g and zinc from 25.88µg/

g to 1083.4µg/g.dw. In kidney and muscle, the range of copper accumulation was 1.278µg/g to

63.762µg/g and 0.472µg/g to 1.46µg/g.dw respectively. The range of zinc accumulation in kidney

and muscle was 37.7µg/g to 841.474µg/g.dw. Copper in control fish in gill, liver, kidney and

muscle ranged from 1.298µg/g to 1.414µg/g, 13.326µg/g to 13.594µg/g, 1.264µg/g to 4.12µg/

g and 0.038µg/g to1.25µg/g.dw respectively. In control fish the range of accumulation of zinc in



gills, liver, kidney and muscle was 19.64µg/g to 20.234µg/g, 22.126µg/g to 22.242µg/g, 36.99µg/

g to 38.9µg/g and 20.568µg/g to 29.24µg/g.dw respectively after 28 days of exposure. The

mean values and SD value of the results are tabulated and graphically represented (Tables 3.10-

3.17; Fig. 3.9-3.16). Tables 3.17- 3.24 shows the t value and its correlation between the control

and treated samples. The results of the t-test signifies that, the accumulation of both copper and

zinc in the control and treated fishes were significant in sublethal concentration.

3.9 DISCUSSION

The discharge of potentially toxic trace metals into the marine and freshwater environments

has become a global problem. Continuous exposure of freshwater organisms to low concentrations

of heavy metals may result in bioaccumulation, causing changes in the activities of several liver

enzymes (Sorensen, 1991). Fish, as living bioindicator species, play an increasingly important

role in the monitoring of water pollution, because they respond with great sensitivity to changes in

the aquatic environment (Mondon et al., 2001).The process whereby an organism concentrates

metals in its body from the surrounding medium or food, either by absorption or ingestion is

known as bioaccumulation (Forster and Whitman, 1981; Ademoroti, 1996). According to Heath

(1991), fish can regulate metal concentration to a certain limit after which bioaccumulation occurs.

The concentration of metals in an organism’s body, vary from organ to organ and is the product

of an equilibrium between the concentration of the metal in an organism’s environment and its rate

of ingestion and excretion (Oronsaye, 1987; Gerhardt, 1992; Adeyeye et al., 1996). The ability

of each organ or tissue to either regulate or accumulate metals can be related to the total amount

of metal accumulated in the specific organ or tissue. Kotze (1997) reported that physiological

differences among tissues influence the bioaccumulation of a particular metal.

Knowledge on heavy metal concentrations in fish is important with respect to nature of

management and human consumption of fish. Heavy metals penetrate into water reservoirs via

atmosphere, drainage, soil waters and soil erosion. As the concentration of heavy metals in the

environment increases, the metals inevitably enter the biogeochemical cycle (Riget et al., 2004;

Kendrick et al., 1992; Mansour and Sidky, 2002). In contaminated water, heavy metals

accumulate in organisms, which are consumed by fish or penetrate into fish directly through skin

and gill later (Sinha et al., 2002; Surec, 2003). Heavy metals cause the mutation on internal

organs of fish, disturb immune reactions, change blood parameters, and reduce an organism’s

adaptation qualities, vitality, and resistance to diseases. Loss of fry and degeneration and diminution

of valuable varieties of fish are observed as a result of heavy metal pollution (Blasco et al., 1999;



Kime, 1999; Bird et al., 1998; Alabaster and Lloyd, 1994).Usually, many toxic compounds

affect organisms in nature at the same time, each of them having a specific effect on physical and

chemical processes that influence an organism’s condition and reactions. Therefore, in order to

maintain the quality of food it is important to regularly monitor and evaluate the pollution levels in

fish as well as in water reservoirs.

In literature, heavy metal concentrations in the tissue of freshwater fish vary considerably

among different studies (Chattopadhyay et al., 2002; Papagiannis et al., 2004), possibly due to

differences in metal concentration and chemical characteristics of water from which fish is sampled.

The ecological needs, metabolism and feeding patterns of fish and also the season in which

studies were carried out also influenced the metal accumulation. In river, fish are often at the top

of the food chain and have the tendency to concentrate heavy metals from water (Mansour and

Sidky, 2002). Therefore, bioaccumulation of metals in fish can be considered as an index of

metal pollution in the aquatic bodies (Tawari-Fufeyin and Ekaye, 2007; Karadede-Akin and

Unlu, 2007) that could be a useful tool to study the biological role of metals present at higher

concentrations in fish (Dural et al., 2007).

In the present study, the fish Puntius parrah showed higher accumulation of copper in

liver than other organs. Metal accumulation in fish bodies appear as site specific, corresponding

with the metallic toxicity of three aquatic components viz. water, plankton and sediments (Javed,

2003). Dural et al. (2007) and Ploetz et al. (2007) reported highest levels of cadmium, lead,

copper, zinc and iron in the liver and gills of fish species viz. Sparus aurata, Dicentrachus

labrax, Mugil cephalus and Scomberomorus cavalla. Yilmaz et al. (2007) reported that in

Leuciscus cephalus and Lepornis gibbosus, cadmium, cobalt and copper accumulations in the

liver and gills were maximum, while these accumulations were least in the fish muscle. The higher

levels of trace elements such as lead and chromium in liver relative to other tissues may be

attributed to the affinity or strong coordination of metallothionein protein with these elements

(Ikem et al., 2003). According to Allen-Gill and Martynov(1995), low levels of copper and zinc

in fish muscles appear to be due to low levels of binding proteins in the muscles. Canli and Kalay

(1998) determined the concentrations of cadmium and chromium in the gills, liver and muscles of



Cyprinus carpio, Barbus capito and Chondrostoma regium caught at 5 stations on the Seyhan

river system. Liver and gill tissues showed higher metal concentrations than muscle tissue. Thus,

heavy metals when discharged into the river enter the food chain and accumulate in the fish body

(Rauf et al., 2009).

In the present study bioaccumulation of copper in tissue was in the order of

liver>kidney>gills>muscle after a period of 28 days. The high levels of copper in the liver can be

ascribed to the binding of copper to metallothioneins (MT), which serves as a detoxification

mechanisms (Hogstrand and Haux, 1991). Lloyd (1992) found that, the main environmental

factor which affects copper toxicity in water is calcium concentration. This is as a result of the

competition that occurs between these two ions for binding sites in the tissue of the gills and other

organs. This could explain the low levels of copper in gills compared to liver and kidney. Copper

in the alkaline conditions precipitates as carbonate and is non toxic (Dallas and Day, 1993).

In the present investigation, the liver tissue always contained a significantly higher level of

Zn residue compared to control fish. The result of the study follows the trend:

liver>kidney>gills>muscle. The results clearly indicate that the liver appears to be one of the

most important sites for Zn accumulation as it was also evident from some of the earlier findings

of Heath (1987) and Seymore et al. (1994). The high levels of Zn in liver can be ascribed to the

bindings of Zn to metallothionein (MT) which was at highest concentration in liver (Kendrick et

al., 1992). The differences in the level of accumulation in the different organs of the test fish can

primarily be attributed to the differences in the physiological role of each organ (Karuppasamy,

2004). Regulatory ability and functions are also other factors that could influence the accumulation

differences in the different tissues. The Zn concentration in the liver which is not in direct contact

with Zn in water play a major role in detoxification as well as storage, would therefore differ from

the concentration detected in the gill which is in direct contact with Zn in water that plays a role

in the uptake and excretion of the Zn (Romanenko et al., 1986). The Zn level in gills of fish

exposed to the sublethal concentrations of Zn, was significantly higher (P<0.001) than the level

found in the control groups at all exposure periods. The high Zn levels in gill tissue can possibly be

due to the fact that they are the main sites for Zn uptake, particularly in freshwater fish and due to



the large surface that is in contact with environmental water and the very thin barrier separating

the external and internal media of the animal. However accumulated Zn in the gill tissue of Puntius

parrah was lower than that in the liver and kidney. Lower amounts of Zn in gills suggest that Zn

is excreted more rapidly and reduce the body burden of Zn and suggest that Zn are not accumulated

in prolonged period in gill tissue. According to Madhusudan et al. (2003), the excessive Zn in

muscle tissue was transferred to other organs in the fish exposed to Zn contaminated system. It is

evident that the test fish of P.parrah had a tendency to push zinc burden to other tissues like

kidney from muscle during metallic stress, perhaps may be upto some limit of exposure

concentration and time. But this Zn metabolism in fish definitely does not allow for excessive

ambient metal in muscle tissue to pose a threat to fish.

During the whole period of the study, the lowest zinc load was found in the muscles. In

their studies, Kroupa and Hartvich (1990) also reported low zinc levels in muscles. When zinc in

water rises to a level where the amount entering the organism through the gills exceeds the

requirement for this metal, the surplus has to be excreted (Lloyd, 1992).This could explain the

low level of zinc in gills from results of the present investigation. High levels of zinc leads to further

gill damage involving the separation of epithelium, enlargement of central and marginal channels,

occlusion of central blood spaces, and results in decreased oxygen consumption, the ability to

transport ions across the gill surface and an increase in hypoxia ventilation frequency(Lloyd,

1992). Zinc can bioaccumulate in the liver reflecting the multi-functional role of the liver in the

detoxification (through metallothioneins binding) and storage processes (Carpene et al, 1990). It

has the ability to bind to metallothioneins, although Cu has a greater affinity for proteins and is

able to displace zinc (Roch et al, 1985). In slightly basic, anoxic marsh sediment environments,

zinc is effectively immobilized and not bioavailable (Gambrell et al, 1991). Very high abundance

of soluble zinc are present under well oxidized conditions and at pH 5 to 6.5, whereas low

abundance of soluble zinc are present at pH 8 under all redox conditions and at pH 5 to 6.5

under moderately and strongly reducing conditions (Gambrell et al, 1991).

Gbem et al. (2001) recorded highest Cr, Cu and Zn concentration in liver and gill tissues

of Clarias gariepinus. Comparison with available literature from South Africa further supports



the general ranking order reflected in the current study: liver>kidney>gills>muscle. Avenant-

Oldewage and Marx (2000) recorded the greatest Cr concentration in the gills and the greatest

Cu and Fe concentrations in the liver. Retief et al. (2009) also recorded the highest Cr, Mn, Fe,

Cu and Zn concentrations in liver and the lowest concentrations in muscle. The latter trend was

confirmed by Ayandiran et al. (2009) for Mn, Zn and Cu. Zn was however found to occur at

higher levels in the gills by Van Aardt and Erdmann (2004), but these authors also recorded the

highest Cu concentrations in liver. The liver is highly active in the uptake and storage of pollutants

and non-nutritive molecules (Hopson and Wessels, 1990; Sorensen, 1991), while active and

passive exchanges occur between the animal and the aquatic environment through the gills (Eckert

et al., 1988; Kargin, 1996). Several other authors also reported highest essential trace metal

concentrations in fish liver (Yang et al., 2007; Yilmaz et al., 2007; Vinodhini and Narayanan,

2008; Al-Kahtani, 2009; Rauf et al., 2009; Su et al., 2009; De Boeck et al., 2010). Robinson

and Avenant Oldewage (1997) speculate that feeding and biology (e.g. bottom dwelling and

feeding), combined with blood supply mechanisms between the liver and intestinal portal system,

may help explain high metal concentrations in the organs. Mathews and Fisher (2009) also

emphasised the importance of dietary exposure. The fact that metals also accumulate in some

aquatic plants (Moodley et al., 2007), may compound the role fish diet may play in metal accumulation.

The accumulation level and toxicity of heavy metals to organisms vary according to the

type of metal and the species of organisms. Within the same species accumulation level and

toxicity of same heavy metal can also vary as discussed in the present study. Heavy metals can be

transferred through the higher classes of the food chain once accumulated by the organism. An

increase in metal remnants in food chain present in an ecosystem reaches to thousands folds in

birds and human fed on aquatic products. Fish is one of the main food sources, and as a part of

aquatic life they are subject to the maximum toxic effects due to metals. So, it is very important to

determine the accumulation levels of heavy metals in fish that source of high proportion of protein

sources in the food chain for human health and sustainable ecological balance. Therefore, this

study was conducted to determine the toxic effects of copper and zinc on the P.parrah under

sublethal concentration. The results have indicated that accumulation of copper and zinc in the

body tissues of Puntius parrah had increased with increasing exposure period in the medium.


distribution of heavy metals in periyar river and...

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