V. N. Bashkin

Review: Behavior of Persistent Organic Pollutants in the Air-Plant-Soil System

A conceptual model for transformation of environmentally widespread persistent organic pollutants (DDT, HCH, PCBs and benz(a)pyrene) in the air-plant-soil system was developed. Basedon this model, analyses and systematization were made in order to assess the empirical generalizations, models, and hypothesesfrom different literature sources related to studying the peculiarities of the above-mentioned phenomenon. They are illustrated by the examples of pollutant behavior on the agricultural areas of the former Soviet Union.

Calculation and mapping of critical loads of S, N and acidity on ecosystems of the Northern Asia

On the basis of modified simple steady state mass-balance equations, the critical loads for nutrient and acidifying nitrogen as well as for sulphur and acidity have been calculated for various ecosystems of northern Asia using simplified expert-modelling GIS and grid cells 150×150 km. The minimal values of critical loads of nitrogen, CL(N), (<50eq/ha/yr) were shown for arctic and subarctic ecosystems and the maximal ones (>300eq/ha/yr) for ecosystems of chernozemic and chernozem-like soils in southern Siberia and the Far East. The minimal values of critical loads of sulphur, CL(S), as well as acidity were shown predominantly in the northern part of east Siberia and in the Kamchatka peninsula and the maximal ones for ecosystems having neutral and alcaline soils. The corresponding exceedances were indicated for many regions of the northern part of Asia with maximal values for regions of Ural mountains, frontery of Kazakhstan, Altai, lower Yenisei river flow, Far East, Sakhalin and South-Kurilean islands.

Organochlorinated compounds (PCBs and insecticides) in irrigated agrolandscapes of Russia and Uzbekistan

The spatial and temporal distribution of persistent chlororganic compounds in the form of insecticide residues—DDT, DDE, DDD, HCH and industrial pollutants—polychlorobiphenyls (PCBs) has been monitored in various components of irrigated agrolandscapes (soil, water, bottom sediments) in the Moscow region, the Kuban lowplain of the Krasnodar region (Russia) and in the Samarkand oasis (Uzbekistan) for the period 1989–1990. The widespread occurence of PCB compounds requires action for their hygienic control and monitoring. The main chlororganic pollutant found were DDT residues and their content in soils and bottom sediments in all regions under study exceeded in many cases the existing baselines (100 µg/kg). Special attention has been given to the ratios between various metabolites and isomers of chlororganic insecticides as well as between various homologs of PCBs among which tetrachlorobiphenyls were predominant in soils, bottom sediments and surface waters.

Biogeochemical approaches to assessment of East Asian ecosystem sensitivity to acid depositon

We used the critical load (CL) concept to calculate ecosystem response to acid deposition in East Asia. The calculation of critical loads to assess the sensitivity of ecosystems to acidic deposition was made using a biogeochemical approach, which took into consideration both rates of biogeochemical cycling and temperature responses. On the basis of these data the soil-biogeochemical mapping has been carried out for the area of East Asia and the CL values for acid-forming compounds have been calculated using modified steady-state mass balance (SSMB) equations. In the north-eastern ecosystems of the Asian part of Russia these values of critical loads for N [CL(N)] and S [CL(S)] compounds are shown to be less than in Europe due to peculiarities of climate, soil and vegetation. The minimum values of both CL(N) and CL(S) are <50 eq/ha/yr (which occur in 8.3% and 40.5% of this area for N and S, correspondingly) and the maximum values are >300 eq/ha/yr. These values are occasionally lower than for corresponding European ecosystems. For the south-eastern ecosystems of the northern part of Thailand the minimum values are <200 eq/ha/yr and maximum values are >700 eq/ha/yr. The minimum CL values (<200 eq/ha/yr) occur in more than 75% of the studied Thai area.

Reclamation of soil polluted by gas condensate using peat compost

An approach to the reclamation (the recovery of fertility) of soil polluted by gas condensate in the territory of a boosting compressor station using peat compost was developed. The efficiency of soil reclamation was evaluated by an analysis of catalase and dehydrogenase enzyme activities and by the sowing and cultivation of perennial grasses in the area.

Uncertainty analysis of critical loads for terrestrial ecosystems in Russia

The goal of this study is to give a comprehensive and quantitative estimation of the uncertainty of computed in different scale nitrogen (N) and sulphur (S) critical loads (CL) values for terrestrial ecosystems of the Northern Asia, European part and the North-Western regions of Russia. The CL values are used to set goals for future deposition rates of acidifying compounds so that the environment is protected. In this research CL values for terrestrial ecosystems are determined using the expert-modelling geoinformation system (EM GIS) approach. UNCSAM software package is used as the tool for uncertainty analysis. The analysis presented here focuses on the estimation and effect of the input source uncertainties and sensitivities on the CL values in various regions under study. In spite of the region, nitrogen uptake by vegetation, nitrogen leaching from terrestrial ecosystems and the difference between deposition and uptake by plants of base cations (BC) are the most influential factors for all terrestrial ecosystems of Russia.

Application of peat to land reclamation in a natural gas production area

The rapid evaluation of the effectiveness of land reclamation (soil fertility restoration) in the abnormal tundra soils of the Tazovsk peninsula (Yamalo-Nenets autonomous okrug) in a natural gas production area was performed. The high efficiency of abnormal soil reclamation by means of peat was confirmed by an increase in the activity of the enzyme dehydrogenase.

CARTOGRAPHIC ASSESSMENT OF RESIDUAL QUANTITIES OF DDT IN AGRICULTURAL LANDSCAPES OF SAMARKAND OASIS, UZBEKISTAN

Three Russian environmental scientists describe a program of monitoring and mapping of accumulations of the now-banned pesticide DDT in a major area of irrigation agriculture in the republic of Uzbekistan—the Samarkand Oasis. Measurements from soil, water, and river/lake/canal bottom sediment samples were taken within the zone of irrigated crop cultivation along the Zeravshan River. The final map product is intended not only as a graphic tool for depicting the spatial distribution of accumulated DDT residues and derivative metabolic compounds, but as an operational document supporting the implementation of measures to mitigate the environmental hazard they pose. Translated by Edward Torrey, Alexandria, VA 22308 from: Geografiya i prirodnyye resursy, 1996, No. 4, pp. 51-54.