Dmitry Viktorovich Ladonin

Within the landscapes of the upper reaches of the Klyazma River, the long-term component composition of natural waters in the system has been studied: snow waters — soil solutions — soil-ground waters — surface waters. It has been determined that the regular excess of the content of the main macro- and microelements in soil solutions in comparison with snow waters at subsequent stages is first replaced by an increase in the concentration of components in soil-ground water, followed by a decrease in the content in surface waters — streams and river waters. It is shown that the relatively high mobility of sodium, magnesium, potassium and calcium, and of the anions chloride and nitrate ions, is accompanied by a significant decrease in the mobility of elements of the family of iron, copper and zinc at the transition from groundwater to surface water. This explains the wide distribution of segregated forms, presented in the form of nodules in soils of semi-hydromorphic landscapes, up to ortsands, and in the boggy conditions of near-terrace depressions on the border with the super-aquatic landscape, the formation of typical bog ores. Thus, the composition of natural waters and its change serves not only as a good, but also a necessary tool for explaining the features of migration of elements in the soil — natural water system.

The total content of lead, the content of its acid-soluble and mobile forms of compounds in sod-carbonate soils of the impact zone of the Cherepovets Steel Mill (Vologda region) were studied. The isotopic composition of lead of its specified forms of compounds has been determined. It is shown that lead, being a part of the gas and dust emissions of the enterprise, is detected in increased quantities up to 6–10 km in the north direction studied by us from the source of pollution. The penetration of technogenic lead compounds down the soil profile up to horizon B is observed. The isotopic ratios of lead ²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁷Pb studied by us reveal clear dependencies on the lead content in soils. For all isotopic ratios in the series «total lead < acid-soluble lead < mobile lead», the contribution of technogenic lead compounds to its isotopic composition increases, since in the same series there is an increase in the proportion of technogenic lead compounds from its total amount. Extrapolation of the dependence of the ratio ²⁰⁶Pb/²⁰⁷Pb on the lead content in the low content area gives the value of this ratio in the range of 1,19–1,25, which corresponds to the isotopic composition of the total lead of the background soils of the European part of Russia. In high polluted soils near Steel Mill, this ratio decreases to 1.10, which corresponds to numerous literature data. The choice of isotope ratio is crucial for obtaining more detailed information about the nature and sources of technogenic lead contamination of soils. Thus, in soils with a low lead content, according to the values of the isotope ratio ²⁰⁸Pb/²⁰⁷Pb, lead is released associated with another source of pollution, presumably from a city thermal power plant operating on coal.

The effectiveness of remediators in detoxification of soils contaminated with heavy metals was studied in a lab experiment. The objects of the study were the soils of the southern tundra, functioning under conditions of anthropogenic impact: Haplic Gleysols (Gelic) and Histic Fluvisols (Oxyaquic). The chemical ability of remediants to bind metals (Ni and Cu), transferring them to a sedentary state in comparison with the reference variants (without any addition of remediants), was evaluated. In experiments, remediants were used in three doses (D1, D2, D3): shungite; diatomite, glauconite and bentonite. To assess the immobilization of Ni and Cu in soils, acid-soluble (CR) forms (extraction of 1 n. HNO₃), mobile forms (ammonium acetate buffer solution with pH 4.8), water-soluble forms of Ni and Cu (1:20 aqueous extract) were determined by inductively coupled plasma mass spectrometry. The effectiveness of soil detoxification during the application of remediants was evaluated by the phytotoxic effect in an express phytoassay with standardized tests (Brassica rapa CrGC and Avena sativa) represented by higher plants. A decrease in the proportion of mobile forms of Ni and Cu by 50% or more in Haplic Gleysols (Gelic) was revealed with the addition of any dose of ameliorants. The greatest effect of reducing mobility was exerted by shungite and diatomite at a dose of D1 — up to 15% Ni and Cu for Histic Fluvisols (Oxyaquic) soil. The use of the selected remediants in the indicated amounts did not reveal a phytotoxic effect on the tests in the experiment.