Priority Toxicants in Elements of Lower Don Ecosystem

The main sources of pollutants entering the Don R. ecosystem in its lower reaches are discussed. The principal sources are navigation, construction of new berths, dredging operations, and transshipment. At the economic revival, the level of anthropogenic load increases every year, producing an adverse effect on the ecosystem. Data of observations carried out in the recent 5 years and focused on the pollution level of water and bottom sediments by oil products, stable organochlorine pesticides, congeners of polychlorinated biphenyls, heavy metals (mercury, lead, cadmium, copper, iron, zinc, chromium, nickel, and manganese), and arsenic. The stable dynamics of accumulation of some pollutants in bottom sediments is demonstrated. Some hazardous toxicants were found to accumulate in the tissues of commercial fish in the Don. The pollution of water and bottom sediments was evaluated in accordance with the Russian and regional standards and the accumulation of toxicants in commercial fishes was evaluated in accordance with the Technical Regulation of the Customs Union.