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allowing controlling their mobility.

The forecast assessments of radionuclides migration in the peat soil (the peat deposit Pogonyanskoye, the Polessye radiation-ecology reserve) under the natural and anthropogenic factors impact had been carried out.

References

1.Brovka, G.P. & Rovdan, E.N. The influence of the sorption kinetics of radionuclides on processes of diffusion and convective transport them in natural media. Proceedings of the National Academy of Sciences of Belarus. Chemical series , Minsk. 1999, 2 : 6367p. (in Russian)

2.Prokhorov V. M. Radioactive pollutants migration in soils. Moskow.: Energoizdat, 1981. 97 p. (in Russian)

3.Deryagin B.V., Churayev N. V., 1980, “Current non-freezing water layers and frost porous bodies

goggling”. Colloid J. V. 42, 5, 842–852 p. (in Russian)

4.Brovka, G.P. Theoretical analysis of radionuclides migration process in frozen rocks”. Colloid J.,

1999, V. 61, 6, 752-757 p. (in Russian)

5.Brovka, G.P., Dedyulya, I.V. & Rovdan, E.N.An experimental study of radionuclides migration in frozen grounds. Colloid J., V. 61, 6, 758-763 p. (in Russian)

6.Lykov A. V. The thermal conductivity theory. Moscow: Vyschaya shkola, 1967. (in Russian)

7.Scofield R.K., Graham-Bryce I.J.Diffusion of ions in soil”, Nature. V.188, No 4755, 1980 , 10481049 p.

8.Rovdan, E.N. ”Forecast and control of hydrothermal and radioecological peat soils conditions”. Ph.D. Thesis, National Academy of Sciences of Belarus, Institute for Problems of Natural Resources Use and Ecology , Minsk, Belarus, 1997. (in Russian)

9.Lishtvan, I.I., Brovka, G.P., Davidovsky, P.N., Dedyulya, I.V., Rovdan E.N.1997 “Forecasting and control of the migration of radionuclides upper soil layers”.One decade after Chernobyl: Summing up the consequences of the accident. Poster presentations-V.2.- Vienna: IAEA, pp. 71-78.

EVALUATION OF THE EFFECT OF DNIPRO RIVER RESERVOIRS ON COASTAL LANDSCAPES

V. STARODUBTSEV, O. FEDORENKO

National Agricultural University, Geroiv Oborony st.15, Kyiv, 03041, UKRAINE

1. Introduction

Construction of large reservoirs and their cascade causes large-scale environmental changes in their vicinity and in the entire basins of rivers with a regulated run-off [1-3]. The achievement of the main objectives of (hydropower utilization, flood control, irrigation, etc) is usually accompanied by the flooding of fertile lands in river valleys, waterlogging and water table elevation, swamping, development of saline and alkaline (sodic) soils and stream-bank erosion. Downstream of the dam some profound changes occur in the characteristics of runoff water and in the landscape of river valleys and deltas, as a result of which the landscapes become steppe-like or desert-like [2-3]. The research work allowed us to identify some general regularities of coastal lands waterlogging and landscape changes which depend on geographic conditions of the region. At the same time, there is a need to perform special investigations of mentioned processes in reservoirs, where some unique practices of hydrotechnical construction were realized to protect the reservoir coastal lands from floods and waterlogging. Such a situation is characteristic for reservoirs on the Dnipro (Dnieper) river in Ukraine. This situation is aggravated by a nuclear-waste pollution of the region [4-6]. The Dnipro river in 50-70s was transformed into a series of reservoirs 855 kilometres long, which crosses the territory of Ukraine from the forests on the north to the dry steppes on the south. A run-off regulation caused a flooding of 0,5 million hectares of lands, changed environmental situation and conditions for farming and forestry on the adjacent territories.

2. The effect of Kyiv reservoir on coastal soils and landscapes

On the territory round the Kyiv reservoir in the forest belt soddy-podzolic soils are spread. These soils (sands and loamy sands) are typical by low organic matter content and acid reaction. They are used primarily in forestry and in farming. Soils along lower banks of the reservoir (left and northern part of right banks) were subject to ground water table elevation on an outstretch of land 0,5- 1,0 km wide. A waterlogging was not observed any further along the left bank of the reservoir because of special conservation structures, such as protective dams and drainage channel, which protect the lowland territory between the rivers Dnipro and Desna. There is a strengthening of the processes of gleyzation and sometimes swamp-formation in soils, which became excessively wet under the reservoir impact. This changes the water regime, morphological features and chemical properties of soils. The reaction of formerly acid soddy-podzolic soils

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has become neutral under the impact of seepage waters containing calcium hydrocarbonate. Soil organic matter (SOM) content has increased from 0,8-1,0 to 1,2-1,9%. The reduction of hydrolytic acidity caused an increase in percentage base saturation [4]. On excessively wet plots with high water table there takes place the formation of soddy-gley, meadow and meadow-swampy soils gleyed all over the profiles. Organic matter content in their surface horizons is now over 2%.

The research results have enabled us to subdivide the territory associated with the Kyiv reservoir according to changes in the environmental status of soils [4, 6]. Regions I-III were outlined on the left bank. Soils in these regions were wetted by the infiltration water, flowing from the basin of a reservoir to the drainage channel, which was designed along the entire left bank. The degree of soil wetness is increasing from the north (region I) to the south (region III). The landscapes and soils of the region I are characterized by a line of soil profiles (description of the lines of profiles 1-5 was published in [4, 6]). Zonal soils here are suitable for the forestry (coniferous forests). In the lowlands of topography with high level of ground water table (1-2 m below the soil surface) slightly waterlogged gleyed soils with less acid reaction are formed. In the region II an environmental situation is influenced by the wetting of the territory by seepage water, which move towards the drainage channel. According to ground water levels the soils become considerably waterlogged (soddy-gley) on a coastal strip 200-250 m wide. At a distance 300-350 meters from the coast there is a moderate water table elevation and at distance 400450 meters slightly waterlogged soils are being formed. The coastal territory is used for pastures and grasslands. The western part of the region is forest. In the region III adjoining the dam of a hydropower plant (lines 2 and 2a) a territory between the Dnipro and Desna rivers is protected from floods by a special concrete-faced dam. The soils next to dam are less waterlogged and towards the drainage channel they become moderately and sometimes considerably waterlogged.

On the right bank of the reservoir (region IV, Fig.1, line 3, [4, 6]) soil creep, stream-bank and surface erosion are encountered. On the elevated coasts, 30- 40-meters high over the water level of the reservoir, the destruction of soils continues. Only in the southern part of the region near the town of Vyshgorod, stream-bank erosion has ceased and surface erosion becomes weaker due to the practices of erosion control (terracing and afforestation of slopes) and concrete-wall fencing of the banks. In the region V the processes of bank erosion are accompanied by fragmentary waterlogging of soils in the locked depressions of topography (Fig. 2, line 3b, 3v, [4, 6]). In the northern direction the processes of bank erosion gradually disappear, but the waterlogging of soils becomes more intensive. The changes of vegetation correspond to those of the soils: meadow grasses grow on intensively waterlogged soils; deciduous forests with meadow grasses are associated with moderately waterlogged soils; mixed forests - with slightly waterlogged ones. And only beyond any reservoir-associated wetness (Fig.1, line 4b, [4, 6]) there are typical coniferous forests. In the VIth region the processes of stream-bank erosion are practically absent, but soil waterlogging on the territories near the reservoir is intensive (Fig.2, line 6, [4, 6]). Large areas of farmland are waterlogged, primarily grasslands, including those ameliorated by drainage.

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Radionuclides migration in soils of the coasts. Nuclear pollution of the territories associated with the Kyiv reservoir is now a serious environmental problem. We investigated the migration of radionuclides in soils of both low (waterlogged) and high coastal plains, the latter having stream-bank and surface forms of erosion (Fig. 1, 2, [4, 6]). It was found that since Chernobyl accident 137Cs radionuclides have penetrated into the soil profiles to the depth 15-25 cm, depending on soil type, organic matter content and texture. The majority of the radionuclides was accumulated in forest litter and sod as well as in the surface 7-10 centimetres layer of the soil rich in organic matter, where pollution was up to 850-1839 Bq/kg. About one-tenth of the initial amount of pollutants has penetrated 15-20 centimetres deep, and even less - to 20-25 centimetres. An exception are the soils on the slopes of the territory near the village of Lyutezh (Fig.2, line 3 and 3a, [4, 6]) as well as the soils subjected to ploughing (line 4a), in which the radionuclides have penetrated deeper [6, 8]. On the slopes where the soils were subject to erosion only one-fourth of the initial pollution remained (269 Bq/kg, line 3a). In general, the downward radionuclide migration into the soddy-podzolic soils under the impact of precipitation still goes on, though slowly. A slight accumulation of nuclear wastes was detected in a capillary fringe of the waterlogged soils on the left bank. Their migration takes place with the seepage of water from the reservoir to the adjacent territories and afterwards with capillary fringe the radionuclides rise to the low horizons of the soils. But on the right bank this process does not occur. Results of our investigation were partly published earlier [4, 6], so we show here last data only (table 1). Along the elevated right bank the newly formed deposits (because of soil erosion) partly overlay the polluted bottom sediments.

Table 1. 137Cs Activity in the Coastal Soils of Kyiv Reservoir

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3. The effect of Kaniv reservoir on landscapes and soils

Kaniv reservoir is situated in forest-steppe zone. Parent materials of soils on the high right-side bank are the silt-loam loesses. At the altitude of the reservoir level there are the layers of marl clays, which are helpful in preventing of a streambank erosion. On the lower left-side bank there are the alluvial sediments of the sandy terrace of the Dnipro, which further to the east become overlain by the loesslike sediments. There are a series of unique practices of coastal land protection from submerging and waterlogging.

We have identified 8 coastal regions according to soils changes (Fig.3, [4, 6]). 1-st region on the right bank is the polder system with soddy and podzolic-soddy gleyed and meadow-swamp soils that is protected by a dam against the submergence. It could be used for grasslands, pastures and recreation. 2-nd region is a territory occupied by the buildings of Trypilska heat power plant. 3-d region is represented by the high-bank territory covered with chernozems and dark-grey forest soils. The coasts are subject to bank erosion, sheet and gully erosion and landslips. 4-th region is the high-bank coastal territory between the towns of Rzhyschiv and Kaniv covered mainly by dark-grey forest soils. There is fragmentary bank erosion, but high cliff does not form on the bulk of the coasts. However, gully erosion and landslips are encountered here. The region is important for recreation and forestry.

The following regions have been identified on the left bank: 5-th region is a system of polders with mostly soddy, meadow and meadow-swamp waterlogged soils. The pumping stations are regulating their water regime. The lands here are being used as grasslands and pastures, but not effectively. 6-th region is a waterlogged territory containing numerous lakes and coastal bays and covered by meadow and swamp soils. This territory is important for recreation, hunting and fishing. 7-th region is a sandy terrace of the Dnipro. Predominant here is soddypodzolic soils of sandy and sandy-loam texture. A terrace is being very slightly waterlogged and important for recreation, forestry and a nature protection reserve. 8-th region is a system of polders protected from submergence by a dam with the highway.

Nuclear wastes less pollute landscapes here. The activity of 137Cs in surface horizons (0-5 cm) of Kozyn polder soils reaches 250-300 Bq/kg. Lower in the profile it decreases and only in the capillary fringe reaches 40-50 Bq/kg (Table 2, line 10, [4, 6]). Hydromorphic soils on the left bank are less polluted. Even in the surface horizon the activity of 137Cs does not exceed 100 Bq/kg (line 13, p.3; line 11, p.22). But the radionuclides have penetrated to a greater depth being chelated by the fulvic organic acids. Only near village of Tsybly waterlogged coastal soils are more polluted in upper part of profile. It caused by a capillary raising of polluted ground water and entering of radioactive particles with surface waters in 1986 (line 8, p.1). The soils on the high right-side coasts are very weakly polluted (line 7, 14), except the territory near village of Khodoriv, where the activity of 137Cs in the upper horizons of chernozems reaches 340-370 Bq/kg, (line 15, p.1).

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4. The effect of Kremenchuk reservoir on soils

Kremenchuk reservoir was built in 1961 on the south of the forest-steppe zone. The effect of the reservoir on the ecological status of the coastal landscapes is less investigated. So we propose a schematic zoning of the coasts (Fig. 5, [4, 6]). On the right-side bank we identified 4 regions: I – High rough coasts with eroded chernozems, where bank erosion and landslips take place. This territory is suitable

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for forestry. II – High coasts with typical chernozems where abrasion and surface erosion of soils take place in the thin strip on the shore only. III – Polder system with lakes and swamps. This territory is suitable for fish farming. IV – Lowland territory with complex of waterlogged soils and lakes that has good prospects for fodder grass production.

On the left-side bank we identified 5 regions: V – Lowland territory, divided by numerous riverbeds, covered with a complex of hydromorphic and zonal soils. Waterlogging of soils manifests itself more strongly in northwest part of the region. This territory is fit for a forestry and fodder production. VI – High coastal territory covered with typical chernozems that is not subject for waterlogging. An agricultural land use has not any restrictions. VII – Polder system that can be used mainly for a fishery and hunting. VIII – Territory, which adjoins the polder system on the northwest (Fig.5, 6, line 2). There are salination and alkalisation processes in waterlogged soils. This territory is used as the agricultural lands and grasslands. IX

– Lowland territory, adjoining the estuary of river Sula. Swamp, meadow and meadow-chernozemic soils are prevailing here. Processes of a salination are more intensive in waterlogged soils. It is mainly grasslands and pastures. X – Elevated territory covered with typical chernozems, which are a subject for slight waterlogging only (Fig.6, line 1). There are weak processes of salination and alkalisation in deep horizons of waterlogged soils. An agricultural land use has not restrictions so far here.

The most danger processes in the coastal landscapes are salination and alkalisation of the waterlogged soils (Table 3).

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5. Conclusion

The processes of land waterlogging, bank erosion and soil salination and alkalisation take place on the coastal landscapes of Kyiv, Kaniv and Kremenchuk reservoirs. We identified some regions on these reservoirs coast according to the intensity and peculiarities of such processes.

An important environmental characteristic of landscapes on Kyiv and Kaniv reservoirs coast is their pollution by nuclear wastes. The radionuclides (137Cs) have penetrated into the soil profile to the depth 15-25 cm, but their predominant part is concentrated in sods, forest litter and the upper 7-10-cm layer of soil. On elevated banks the nuclear wastes are subject to surface erosion while on low banks is a slight accumulation of radionuclides in the capillary fringe of soils waterlogged by seepage waters.

References

1.Reservoirs and Their Impact on the Environment. 1st ed. MAB UNESCO, Moscow : Nauka, 1986. 367 p. In Russian.

2.Starodubtsev, V. M.: The Impact of Reservoirs on Soils. 1st ed. Alma-Ata: Nauka, 1986. 296 p. In Russian.

3.Starodubtsev, V. M.: Changes of Soil-Ameliorative Conditions in River Basins Caused by Water

Management Construction. A Precis of Doctor of Biology Thesis. Novosibirsk. 1988. 36 p. In Russian.

4.Starodubtsev, V.M. – Petrenko, L.R. – Kazanina, O.V.: The Effect of Kyiv Reservoir on Environmental Status of Soils. // Journal of Hydrology and Hydromechanics. Bratislava. N 47. 1999. No 5. Pp. 366-377. In English.

5.Starodubtsev, V.M. – Kolodyazhnyy, O.A. - Petrenko, L.R. et al.: Soil Cover and Land Use in Ukraine. Kyiv: Nora-Print, 2000. 98 p. In English.

6.Starodubtsev, V.M. - Petrenko, L.R. - Fedorenko, O.L. et al.: Radionuclides Pollution in Soils of the Kyiv Reservoir Coasts after Chernobyl Accident. / Fifth International Symposium and Exhibition on Environmental Contamination in Central and Eastern Europe, Prague, 2000. P.215. In English.

RADIATION EFFECTS ON THE POPULATIONS OF SOIL INVERTEBRATES IN BELARUS

S. MAKSIMOVA

Institute of Zoology of NASB, Akademicheskaya str., 27, Minsk, 220072, BELARUS

1. Introduction

On April 26, 1986, the Chernobyl Nuclear Power Plant (CNPP), located in the Kiev region of northern Ukraine, 12 km from the Belarusian border, exploded accidently. As a result of the accident 1.95x10 18 Bq of radioactive material, the largest amount ever reported, was released into the environment [1]. A radionuclide content exceeding 37 kBq m -² resulted in contamination over 46 500 km ² of surface soil in Belarus. This area amounts to 23 % of the total territory of the Republic. Within this contamination region a 30-km zone around the CNPP was therefore heavily contaminated.

Investigation of the long-term impact of radionuclides on the zoocenosis in the contaminated region is of interest because a precise description of the changes in the faunal complexes will permit a better understanding of the nature and the rate of recovery. To study the effects of ionizing radiation on terrestrial ecosystems it is essential to make observations on soil fauna. They comprise 90 – 95 % of all animal species and 90 – 99 % of total zoomass. Their high population density is stable. Since they also have permanent feeding habits (phytophagous, saprophagous and zoophagous), soil arthropods represent a convenient subject for elucidation of the ways and quantitative patterns of radionuclide migration in biogeocenoses, and may be used as bioindicators of contaminated territories [2].

The following requirements are imposed upon animals used as bioindicators of contamination by radioactive isotopes [3]: (a) high density and metabolism level; (b) great length of life; (c) intensive reproduction; (d) a small home range; (e) sedentary way of life; (f) permanent contact with the anthropogenic factor under study; (g) available collection of mass samples; (h) sensitivity to the factor concerned; (i) fairly large size in order to facilitate dissection.

Investigation of the long-term impact of radionuclides on the zoocenosis in the contaminated region is of interest because a precise description of the changes in the fauna complexes will permit a better understanding of the nature and rate of recovery. As part of a larger study of the impact of the CNPP event on the zoocenosis of the various biogeocenoses , we undertook a study of the soil mezofauna.

The main goal of our study was to investigate the character of effect of a high radioactive background level on soil invertebrates. The objectives of the study were (1) to investigate the main trends in the changes of the soil invertebrate communities subject to radioactive contamination; (2) to reveal the character and degree of the radiocontamination effect on the functional groups; (3) to characterize the state of invertebrate hemolymph under radiological pressure.

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