ОСОБЕННОСТИ ФЕРМЕНТАТИВНОГО ДЕГИДРИРОВАНИЯ ОРГАНИЧЕСКИХ ВЕЩЕСТВ В ПОЧВАХ, ЗАГРЯЗНЕННЫХ ТЯЖЕЛЫМИ МЕТАЛЛАМИ

Abstract

The influence of heavy metals of hazard classes I (Pb, Cd, Zn) and II (Cu) on the dehydrogenase activity of soils, which plays an important role in the transformation of organic matter in them, was studied. An annual model experiment was carried out on three types of medium-loamy soils (gray forest, typical chernozem, urbanozem) with the introduction of different doses of lead and cadmium in the form of acetic acid salts, zinc and copper in the form of sulfates. A decrease in the intensity of dehydrogenation of organic substances with an increase in the dose of the studied metals on 3, 90, 180 and 360 days from the beginning of the experiment was revealed. This was confirmed by reliable correlation coefficients, which were in the range (-0.63) – (-0.99) at p ≤ 0.05. This pattern was already evident at minimal doses of pollutants. An increase in the content of toxicants increased the inhibitory effect. Lead in different doses reduced the intensity of the processes of dehydrogenation of organic substances by 28-46%, cadmium by 4-42%, zinc by 2-35%, copper by 3-45%. During the experiment, the type of soil with greater resistance of dehydrogenases to pollutants was not identified. In annual dynamics, the intensity of dehydrogenase reactions decreased in gray forest soil by 4-40% and typical chernozem by 4-32% and in urbanozem by 3-45%. The processes of transformation of organic compounds in soils are dynamic in time and proceeded differently depending on their type and metal. The established regularities in the change of dehydrogenase activity allow us to recommend it as a criterion for assessing the negative impact of lead, cadmium, zinc and copper on the dehydrogenation of organic substances in soils due to enzyme systems.