From the samples of gradually drying (beginning from the field moisture capacity, FMC) soddy-podzolic sandy loam soil (Albic Retisol (Loamic, Ochric)) contaminated with Zn were isolated the soil solutions (SS) by centrifugation, while from the other samples of the soil, moistened to FMC, various energy fractions of the SS were pressed using a hydraulic press. The acidity of the centrifuge solutions extracted from the soil of the experiment variant with the cultivation of plants ("barley") was, on average, 1 pH higher than on "bare fallow", and decreased with decreasing soil moisture content. The acidity of the solutions extracted from the soils of the "bare fallow" variant in the same range of soil moisture content practically did not change. It was also found that in more acidic solutions from the "bare fallow" variant the content of Ca, Mg, Mn, Zn and K was 2.4 - 6.9 times higher than the content of these metals in solutions from the "barley" variant. The positive correlation between pF and pH was clearly observed for the pressed solutions from the soils of both variants. Concentrations of Ca, Mg, Sr, Ba,Zn, K and Na in successively pressed fractions of SSs from more acidic soil of the "bare fallow" variant, on average, 3.0 - 8.4 times exceeded their concentrations in similar fractions of solutions of the "barley" variant and showed an inverse correlation with soil moisture (pF value).

The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn 2+ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P) Zn ). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.

The relationship between the main physicochemical properties of soils and the accumulation of natural Zn and 65 Zn radionuclide has been studied, and the capacity of soils to limit the mobility of the element in the soil–plant system has been assessed. The contribution of each of the selected soil state parameters to the accumulation of zinc by barley has been determined, and the soil state parameters have been ranked. It has been found that the largest contributions to the variation of the resulting parameter ( 65 Zn accumulation coefficient, K a ) are made by mobile Fe (25%), free carbonates (21%), and acid-soluble Zn (18%). The largest contributions to the Zn ac K a are made by free carbonates (13%) and mobile Fe (8%). The contributions of physical clay and organic carbon in soils and qualitative composition of humic substances are almost similar (4% for each). No differences in the inactivating capacity of different soils (soddy-podzolic soils, gray forest soils, and chernozems) for 65 Zn are observed. This is related to the fact that the transfer of 65 Zn to plants is statistically significantly controlled by the contents of free carbonates, mobile iron, and potentially plantavailable forms of stable natural Zn (carrier of 65 Zn) rather than the quantitative and qualitative composition of organic matter and the degree of dispersion of mineral particles. The analysis of the Zn ac K a / 65 Zn K a ratios has shown that the share of plant-available Zn in the acid-soluble form of the metal (1 M HCl) is 0.61 on the average for the studied soils, and its share in the total Zn content in the soils is only 0.14.

The quantitative composition of biogenic macroand microelements of milk is known to be closely connected with the chemical composition and environmental pollution of fodders by heavy metals. During grazing and stabling periods we examined feeds and milk from milk cows on private farms within Bryansk Province (Klintsovskii and Novozybkovskii regions, 2004-2007) contaminated by 137Cs (670-1010 kBq/m 2) after the Chernobyl accident. During the monitoring all animals received a specific enzyme, ferrocyn, which provided effective decrease in milk contamination by 137Cs, at a daily dose of 6 g/head for 4 years. The absence was shown of critical concentrations of heavy metals in milk in radiocesium comtaminated areas in the Bryansk region. Quantitative variations in the composition of macroand microelements in milk were connected with the diet mineral composition and physiological condition of cattle. The reasons for variations in the mineral metabolism of tested cows were mainly the species composition of vegetation and the condition of local plots in the spring-autumn period, as well as non-certified components of the ration in the indoor period. The levels of chemical elements decreased or increased slightly in the milk which was less contaminated with 137Cs, except Co and Al, which increased 1.8 and 1.5 times, respectively (0.14-0.23 mg/l). Salting on private farms did not always meet the requirements. The existing Co deficit in pasture fodder in the region needed a relevant correction by mineral additives. The use of ferrocyn did not have a noticeable influence on mineral metabolism in animals, but reduced the 137Cs level in milk from 680 to 95 Bq/l, if the pastures less polluted with 137Cs were also used. Overall, our data on mineral metabolism and milk composition in areas affected by significant radioactive contamination after the Chernobyl accident showed the effectiveness of countermeasures applied in the region.