CHANGES IN THE BIOLOGICAL STATUS OF GRAY FOREST SOILS OF WESTERN CAUCASUS UPON POLLUTION BY CADMIUM, ZINC, MOLYBDENUM AND SELENIUM

摘要

Caucasus possesses unique natural resources. However, active economic, recreational and touristic development of the region results in increased anthropogeneous influence on the natural ecosystems. One of the negative consequences of this impact is chemical contamination of soil. Significant part of the soil cover of Western Caucasus is gray forest soil. However, it remains poorly studied, including its resistance to pollution. It has been found that pollution of gray forest soils of the Western Caucasus with Zn, Cd, Mo, and Se results in deterioration of the soil biological state: the total number of bacteria reduces, activity of catalase and dehydrogenase, and cellulolytic ability deteriorate, the number of bacteria of genus Azotobacter reduces, and the indicators of radish germination and initial growth deteriorate. In most cases, the degree of biological indicators' deterioration is directly dependent on the concentration of soil contaminants. By the degree of negative impact on the biological state of gray forest soils of the Western Caucasus, the studied elements form the following sequence: Se > Zn >= Cd > Mo.