trends in impact of acidification on groundwater bodies in the czech republic; an estimation of...

Journal of Atmospheric Chemistry (2006) 53: 1–12

DOI: 10.1007/s10874-006-0911-0 C© Springer 2006

Trends in Impact of Acidification on Groundwater

Bodies in the Czech Republic; An Estimation of

Atmospheric Deposition at the Horizon 2015

ZBYNEK HRKAL1, HANA PRCHALOVA2 and DANA FOTTOVA3

1Charles University, Faculty of Sciences, Dept. of Hydrogeology, Albertov 6 Praha 2 128 43,Czech Republic, e-mail: [email protected], tel/fax: +420 2219515622Water Research Institute TGM, Podbabska 30, Praha 6, 160 62, Czech Republic,e-mail: Hana Prchalova/Praha/VUV/[email protected] Geological Survey, Geologicka 6, 15200 Praha 5 e-mail: [email protected]

(Received: 15 September 2004; accepted: 18 January 2005)

Abstract. The acidification of surface and groundwaters is a long standing issue in the Czech Republic

which culminated in the second half of the last century by mass extinction of forest cover in many

mountainous regions. The total deposition of sulfur at that time was reaching as much as about

108 kg/ha/year. This resulted in a decrease of alkalinity in groundwaters, decrease of pH and on the

other hand an increase in concentration of nitrates, sulfates, berylium and aluminium. Desulfurization

of power plants and attenuation of heavy industry leads to a decrease in sulfur deposition down to

the present mean values around 16.5 kg/ha/year. It is expected that around the year 2010 the sulfur

deposition should not have a substantial impact on the environment providing the similar trend would

continue. However, a reverse trend can be observed in deposition of nitrogen. The growth of road

traffic and more frequent use of earth gas for heating lead to a dramatic rise in nitrogen throughfall

of which mean value increased from 15.4 kg/ha/year in 1990 up to 25.7 kg/ha/year in 2001. If such

trend continues in future, then the mean values of nitrogen throughfall would attain 37.8 kg/ha/year

in 2015, so that the nitrogen would take over the role of sulfur in acidification. Therefore, the problem

of acidification in Central Europe is by no means resolved, only the structure of acidification input

has been changed.

Key words: acidification, atmospheric deposition, groundwater, Czech Republic

Introduction

One of the problems relating to water supply and distribution to be resolved inthe Czech Republic as the new member of the European Union is the demarcationof endangered groundwater bodies. The term ,,endangered“ means that a specificgroundwater body in 2015 will not be in fair condition. One of the partial steps re-solving this problem is the analysis of trends in “pressure” – i.e., the anthropogenicactivities which have negative impact on the quality of groundwater bodies. Theacidification represents an important regional pressure affecting the quality of sur-face and groundwaters in the Czech Republic. The major source of acidification

2 ZBYNEK HRKAL ET AL.

are enhanced concentrations of sulfur and nitrogen in atmospheric deposition andfrom farming. The main objective of this paper is to describe the methodology ofarea demarcation of nitrogen and sulfur input at the present time and in the year2015, and presentation of achieved results.

Brief Summary of Historical Development

The negative impact of acid deposition in the Czech Republic goes back to thesecond half of 19th century when mining for low quality lignite high in sulfur in theKrusne hory piedmont basins had begun. The output had gradually been increasingtill the eighties of the last century when it reached maximum amounting to roughly75 million tons a year (Novak et al., 2000).

Due to the impact of acid atmospheric deposition the local ecosystem was com-pletely disturbed in the eighties of the last century, which resulted in mass extinc-tion of the forest cover in apical parts of the Krusne hory (Kubelka et al., 1992).The process of acidification has had a considerable impact on the quality of localgroundwaters. The alkalinity dropped considerably when compared with results ofchemical analyses from the fifties of the last century. The HCO3 locally completelydisappeared from water in apical parts of the mountain range. On the other hand,the concentrations of nitrates and sulphates increased (Hrkal, 1992). Average ni-trates concentration of 0.06 meq/l in the period 1955–69 increased to 0.31 meq/l inthe period 1980–1990. Fivefold increase in nitrates concentration in the area withno farming activities over the 25 year period must be regarded as very significant,caused directly by atmospheric deposition or by rapid changes in vegetation cover(Hrkal and Fottova, 1999). Due to the removal of forest cover reduced the propor-tion of dry deposition, the sulphates concentration changed not so dramatically. Onthe foothill region average sulphates concentration increased from 1.2 meq/l in theperiod 1955–1969 to 1.5 meq/l in 1980–1990 and on apical, completely deforestedzone, sulphates concentration remained more or less stable. Similar ecological dis-asters also affected mountain ranges of Jizerske hory, Krkonose and Orlicke horybut with certain delay.

The end of the nineties and the onset of the new millenium are characteristicof significant decline in atmospheric deposition. Obvious downward trend in de-position of sulfur in particular can be ascribed to attenuation of heavy industry andmassive investment into desulfurization of power plants. The total deposition ofsulfur in a region mostly affected by air pollution, i.e., in the Krusne hory piedmontarea, gradually decreased from the highest values in 1980 attaining 108 kg/ha/year(Cerny and Paèes, 1995) down to 70 kg/ha/year in 1994, and later to 40 kg/ha/yearin 2001 (Fottova, 2002).

More complex situation appears to be in the case of nitrogen. The impacts offarming as one of the major sources of NO3 pollution in Central Europe is generallyin decline. Nevertheless, the issue of nitrogen pollution in the Czech Republic has

TRENDS IN IMPACT OF ACIDIFICATION ON GROUNDWATER BODIES 3

some specific features. According to statistical data revealed by the Ministry ofAgriculture the consumption of nitrate fertilizers grew up to values around 100kg/ha/year till the year 1989. However, the change of economic conditions after theyear 1989 caused a sharp decline in their consumption down to about 40 kg/ha/yearin the period 1990–1994.

On the other hand, contemporaneous growth of other sources of nitrogen depo-sition, the road traffic in particular, then the use of earth gas as a fuel, becomes animportant factor showing increasing trend in nitrogen concentrations especially indry atmospheric deposition (Fottova, 2003).

Nevertheless, the acid atmospheric deposition on large areas remains the majorsource of acidification in the Czech Republic. In long term, its impact on ground-water bodies is expected to be reduced. Optimistic forecasts based on downwardtrend in sulfur deposition are to large extent compensated by the rise of nitrogendeposition. As follows from the results of monitoring of a grid of small catchmentsthe issue of improvement of surface and groundwaters quality is much more com-plex, and cannot simply be reduced to straight proportion between the extent ofatmospheric deposition of the quality of waters. It is to be taken into account thatanother important form of ,,pressure“ enters the process of acidification which arethe secondary sources of sulfur in the soil horizon.

Regardless of all positive signs of improving atmospheric conditions, the qualityof surface and groundwaters is only slowly returning to the initial state what canbe ascribed to lingering low concentrations of hydrogen carbonates and perma-nently growing contents of SO4. This may be explained by substantial decline inbuffer capacity of metamorphic rocks, which can be manifested in the Krusne horyarea by the results of studies in an experimental catchment of Jezeı (Novak et al.,2000). Isotopic analyses of sulfur entering and leaving the catchment showed thatthe drained sulfur comes from a soil horizon. It actually represents a secondarysource, which originated during a few decades and which the sulfur is nowadaysgradually washed out from. The study by Novak shows that approximately 30%of the total sulfur content in the drained water comes from organic matter of theupper humic layer of the soil horizon. The rock environment, such as the Krusnehory paragneisses, which is more resistant against the acidification, is able to pro-tect longer the groundwaters against the impact of acid precipitation. However,after dying away or reduction of acid deposition effect, the return to initial condi-tions is likely to last longer since the rock environment may conversely support theacidification.

As follows from the above-mentioned information, the development of “pres-sures” influencing the acidification of groundwater bodies is difficult to forecast.On the one hand there exists a decline in intensity of action of some constituents buton the other the effect of other components grows. It may be worth to look at trendsin development of single components of the ,,pressure“ affecting the acidificationof groundwater bodies in more detail.


The Methods of Data Processing and the Achieved Results

The overall ,,pressure“ consists of a combination of inputs from agricultural activi-ties and atmospheric deposition of sulfur and nitrogen. The definition of the presentstate and estimation of future trends till the year 2015 came out from three types ofbasic materials:

i. wet deposition derived from systematic measurements of the Czech Hydrome-teorological Institute and Water Research Institute,

ii. throughfall and wet deposition of monitoring network GEOMON of the CzechGeological Survey covering exclusively only forested catchments,

iii. data on nitrogen input from agricultural activities on regional scale.

Area distribution of monitoring stations and individual experimental catchmentsis shown in Figure 1.

Atmospheric Deposition of Nitrogen

As concerns the atmospheric deposition of nitrogen, the most complex and difficultappears to be the prognosis of the overall input of nitrogen showing maximumuncertainties because of a number of conflicting trends. Graphic presentation (inform of maps) of the development of nitrogen deposition in the Czech Republicwas divided into several steps. At first the maps characterizing existing conditions

Figure 1. Acidification monitoring network in Czech Republic.


were constructed and then, based on analysis of dominant trends, maps showingpossible development were compiled.

The territory of the Czech Republic was at first divided, basing on the CORINEinterpretation of LANDSAT imagery, into areas with and without forest cover.While throughfall represents the total deposition in forested areas (throughfall isthe rainfall collected under the forest canopy after it passes through the forestcanopy. It will indicate which elements are removed from the trees or perhaps areabsorbed by the trees), the bulk wet deposition prevails in other areas.

The further step included construction of maps expressing the current state ofbulk wet deposition interpolated in a grid 2 × 2 km.

The third step depicted the nitrogen throughfall. As the frequency and density ofinput data on throughfall are considerably lower relative to the number of objectsmonitoring bulk wet deposition, the following procedure was applied, being awareof certain simplification and schematization. The mean value of throughfall in 2001in the GEOMON monitoring network was by 55% higher than the bulk deposition.Therefore, a previous map of bulk deposition grid 2 × 2 km was used as a sourcematerial. The bulk values in forested areas were increased by the established valueof 55%.

The next stage of works was focused on the establishment of development trendand its presentation in form of maps. As follows from a graph of mean valuesof nitrogen deposition in individual years of the period 1990–2001 (Figure 2)there exist two contradicting trends. While the value of bulk wet deposition inall monitored systems was decreasing, the throughfall showed an opposite trend.

Figure 2. Trend of nitrogen atmospheric deposition.


For instance, the nitrogen throughfall in the Orlicke hory area in the year 2000 was81.7 kg/ha/year, which is one of the highest values in Europe. For comparison, so farthe highest nitrogen throughfall around 70 kg/ha/year was reported from Belgiumand Holland, the countries with extensive stock farming (Gundersen 1995, Diseet al., 1998). In this particular case, however, the nitrogen occurred in form ofammonia, whereas N–NO3 prevails in the Czech Republic.

Providing we accept a hypothesis of linear trend in further development ofnitrogen deposition, then the gradual decline in bulk wet deposition will result in2015 in countrywide mean values around 12 kg/ha/year. In contrast, the effect ofdry deposition will increase particularly in forested areas and at higher altitudesabove sea level. The mean value of nitrogen throughfall in the Czech Republic inthe year 2015 is expected to fluctuate around 45 kg/ha/year (Figure 2).

A map showing simulation of conditions of nitrogen deposition in 2015 (Fig-ure 3) is based on data reported in 2001. The data on deposition in 2001 in singlegrids were reduced (in areas with prevailing bulk wet deposition, in an environ-ment without forests) or increased (in areas with prevailing dry deposition, in anenvironment with forests) using the trends equations shown in Figure 2.

In conclusion to this part it is worth to point out another expected change indevelopment of this ,,pressure“. The sources of sulfur deposition, represented inparticular by power plants were in the past concentrated into a few centers. However,the deposition of nitrogen which may ,,successfully“ replace the sulfur in the nextdecade is a phenomenon whose source is more or less evenly distributed across thewhole territory of the Czech Republic, thus expected to act on regional scale. Thisphenomenon can clearly be seen on Figures 3a–3c. The total deposition of nitrogengradually grows from 15.4 kg/ha/year in 1990 up to 25.7 kg/ha/year in 2001. Inthe year 2015, a mean deposition around 38 kg/ha/year can be expected to occurproviding the existing trend will be maintained.

From the practical point of view it means that while the area distribution of totalatmospheric deposition in the past varied considerably (higher around the sourcesof pollution, lower in other areas), then a gradual smoothing of these differencestowards higher values can be expected in the future. The reason for this event isthe rise of road traffic mentioned earlier. This trend can be documented by datasummarized in Table I.

Table I. Increase of road traffic in the Czech Republic (Fottova, 2003)

Czech Republic (10.3 mil. inhabitants) Prague (1.2 mil. inhabitants)

Year Motor vehicles – total Passenger cars Motor vehicles–total Passenger cars

1990 4 039 606 2 411 297 428 769 336 037

2000 5 230 846 3 720 310 746 832 620 663


Figure 3. Maps of distribution of nitrogen atmospheric deposition in 1990, 2001 and prognosis

in 2015.


Atmospheric Deposition of Sulfur

To forecast the development of total deposition of sulfur appears to be more simpleat the first glance. With regard to large investment into desulfurization of powerplants and progressing attenuation of heavy industry it is very likely to expect furtherdecrease in sulfur input. Nevertheless, this at the fleeting glimpse clear developmentmay be in some regions influenced by the governmental ecological policy. The riseof prices of environment-friendly fuels, such the earth gas, leads in some regions tothe return to local heating using poor quality lignite. Consequently, the downwardtrend in sulfur deposition in these regions may be endangered. For instance, thedelayed implementation of desulfurization of the Chvaletice power plant in thelate eighties resulted in transfer of traditional center of sulfur deposition from theKrusne hory area to the Orlicke hory region where the growth of sulfur depositionculminated in 1998 in throughfall equal to 91.1 kg/ha/year (Fottova, 2003).

The data matching regarding the development of bulk wet deposition monitoredby the Czech Hydrometeorological Institute and that obtained from the GEOMONnetwork provided more or less the same results. If we simplify the issue of sulfurdeposition and the trend curves from the nineties interpolated till the year 2015,then the sulfur deposition in 2010 will be on average across the whole territoryof the Czech Republic close to zero. It is very likely that in 2015 the sulfur inputshould not play any important role in the Czech Republic, providing no contingencywould arise (Figure 4).

The total deposition of sulfur depicted in form of maps (Figure 5) was derivedusing the same principles as in the case of nitrogen. The series of maps character-izing the years 1990 and 2001 clearly show the mountain border areas which weremostly affected by sulfur deposition in the past but then an overall sharp decline insulfur impact can also be seen.

Figure 4. Trend of sulfur atmospheric deposition.


Figure 5. Maps of distribution of sulfur atmospheric deposition in 1990 and 2001.

When analyzing the ,,pressure“ then the effect of sulfur deposition in 2015 onregional scale can be neglected. However, the only unanswered question remains theduration of negative impact of sulfur accumulated in soil horizon in mountain areasof the Krusne hory, Jizerske hory, Krkonose and Orlicke hory mountain ranges. Theprognosis of future development of the intensity of effect of sulfur accumulated insoil horizon is extremely difficult to establish. It is obvious that contents of thissulfur will be gradually decreasing with time due to draining but the rate of thisprocess is difficult to estimate. Such considerations can be done only when applyingsome geochemical models.

Input of Nitrogen from Agricultural Activities

The atmospheric deposition is more or less evenly affecting the whole territoryof the country although showing higher intensity in mountain regions with higher


precipitation and with forest cover. However, an important source of acidifica-tion are agricultural activities which become evident in areas with intense plantproduction and animal farming. These areas suffer from much intense acidifica-tion. The process of input of nitrates into rock environment and their migration isvery complex deserving interdisciplinary cooperation including biology, chemistry,pedology, geology and other subjects.

Statistical data on application of manure in single districts since 1950 were usedin order to establish the development of nitrogen input from agricultural activitiestill the year 2015. Unpublished data summarized in a report of the Research Instituteof Crop Production (Klır, 2004) served as another source of information revealinginput of nitrogen from various types agricultural production converted into the areaof arable land. However, the prognosis based on such data suffers from similar un-certainty as in the case of nitrogen input from atmospheric deposition. Moreover,the intensity of agricultural production as a source of nitrogen input is influencedby a number of economic and political factors, which are difficult to foresee. Thediagram in Figure 6 shows increasing trend in application of nitrate fertilizers since1950 until the fall of communist regime in 1989. The use of commercial fertilizersculminated at values around 100 kg/ha/year but the privatization of agriculturalsector after the year 1989 led to sharp decline in application of fertilizers downto less than half values. On the other hand the proportion of nitrogen from animalfarming remained constant for long period of time. Nevertheless, even the inputof this nitrogen shows decreasing trend after year 1989 in accordance with agri-cultural policy of the European Union leading to reduction of cattle breeding. Atthe present time the stock farming represents less than half source of nitrogen thanfertilizing.

As follows from data provided by the Research Institute of Crop Production(Klır, 2004), the farming on arable land in particular remains the dominant sourceof nitrogen. An average input of nitrogen on one hectare of arable land and pastures

Figure 6. Total nitrogen inputs on agricultural land in Czech republic (Klír, 2004).


Figure 7. Changes of nitrogen input structure between 2001 and 2015.

and other cultivated areas in the Czech Republic was 49 kg and 34 kg, respectively.On the other hand, the importance of nitrogen input from atmospheric depositionin forested regions is demonstrated in Figure 7. These regions constitute 30% ofthe country territory so that the mean value of nitrogen input in these areas may beclose to 50 kg/ha/year, which is similar to that in arable land.

Conclusions

The overall ,,pressure“ on groundwater bodies from the viewpoint of acidificationis caused by combination of atmospheric deposition of nitrogen and sulfur andnitrogen from agricultural activities.

The sulfur deposition in the Czech Republic shows a downward trend. An overallmean value of total sulfur deposition equal to 43.6 kg/ha/year in 1999 decreased to16.5 kg/ha/year in 2001. The sulfur deposition in the territory of the Czech Republicis expected to play much less important role around the year 2010 as follows fromthe expected downward trend.

The nitrogen deposition shows much more complex features. While the bulkwet deposition slightly decreases, the dry deposition rises considerably. Conse-quently, the nationwide mean value of nitrogen deposition gradually grows from15.4 kg/ha/year in 1999 to 25.7 kg/ha/year in 2001. The continuing trend wouldlead to mean value of 37.8 kg/ha/year in 2015.

Agricultural activities represent another source of nitrogen. Data on applicationof fertilizers on farmland show dominant effect on arable land in particular, andcurrently many times exceeding values of nitrogen deposition. A mean nitrogeninput on arable land from farming was 49 kg/ha/year in 1999, while its value inpastures and other cultivated areas was 34 kg/ha/year. Nevertheless, the proportionof atmospheric deposition within the total nitrogen load grows, particularly in


forested areas. If the current trend will continue then these areas may suffer fromthe current mean total deposition of 31 kg/ha/year up to 48/ha/year in 2015.

Acknowledegments

Authors would like to thank the Czech Geological Survey for maintaining GE-OMON network monitoring data (project of Czech Ministry of Environment VaV-1D/2/16/II/04). Groundwater monitoring data were obtained with the support of5th Framework Programme project LOWRGREP EVK1-1999-00040.

References

Bormann, F. H. and Likens, G. E., 1970: The nutrient cycles of an ecosystem, Sci. Am. 223, 92–101.

Cerny, J. and Paèes, T. (eds.), 1995: Acidification in the Black Triangle Region, in Proceedings ofthe 5th International Conference on Acidic Deposition, Science and Policy, Czech Geological

Survey, Prague.

Dise, N. B., Matzner, E., and Gundersen, P., 1998: Synthesis of nitrogen pools and fluxes from

European forest ecosystems, Water Air Soil Pollut. 105, 143–154.

Fottova, D., 2002: Material flow in small acidified catchment, Final report D3 LOWRGREP project

EVK1-1999-00040 5th Framework program EU.

Fottova, D., 2003: Trends in sulfur and nitrogen deposition fluxes in the Geomon network, Czech

republic, between 1994 and 2000, Water Air Soil Pollut. 150, 73–87.

Gundersen, P., 1995: Nitrogen deposition and leaching in European forests – preliminary results from

a data compilation, Water Air Soil Pollut. 85, 1179–1184.

Hrkal, Z., 1992: Acidification of groundwater in the Bohemian Massif. Nor. Geol. Unders. Bull. No.

422, pp. 97–102.

Hrkal, Z. and Fottova, D., 1999: Influence des pluies acides a la qualite des eaux de la Republique

tcheque., Bulletin du BRGM, Hydrogeologie 2, 39–45.

Klır, J., 2004: Nitrogen Balance in Agricultural Lands of Czech Republic, Unpublished final report,

Research Institute of Crop Production, Prague.

Kubelka, L., Karasek, A., Ryba, V., and Slodinèak, M., 1992: Reconstruction of forest in immissionendangered area of the Krusne hory Mts, Final Report (In Czech), North Bohemian State Forestry,

Research Branch Krusne hory Mts. Teplice, 139 pp.

Matzner, E., Alewell, C., Bittersohl, J., Lischeid, G., Kammerer, G., Manderscheid, B., Matschonat,

G., Moritz, K., Tenhunen, J. D., and Totsche, K., 2001: Biogeochemistry of spruce forest catchment

of Fichtelgebirge in response to changing atmosperic deposition, in Tenhunen, J. D., et al. (eds.),

Ecologicasl Studies, Vol. 147: Ecosystem Approaches to Landscape Management in CentralEurope, Springer-Verlag, Berlin.

Novak, M., Kirshner, J. W., Groscheova, H., Havel, M., Cerny, J., Krejeı, R., and Buzek, F., 2000:

Sulfur isotope dynamics in two Central European watersheds affected by high atmospheric depo-

sition of Sox, Geochim. Cosmochim. Acta 64(3), 367–383.

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