Ecotoxicological assessment of water quality and ecosystem health: a case study of the Volga River.

A comprehensive assessment is presented of the ecotoxicological situation in the Volga River basin from the viewpoint of ecosystem health. Concentrations of organic and inorganic toxic substances in water are reported. Basic clinical and postmortem signs of fish intoxication are described; changes in the cellular structure of their organs and tissues, as well as disturbances in hemogenesis, developing under the effect of toxic agents, are characterized. The comparative characteristics of several microelements (Ni, Cu, Sr, Al, Zn, Co, Mn, Pb, Cd, Hg, As) found in fish are presented. The main disturbances to fish caused by the accumulation of microelements in their organs and tissues are also considered. Based on dose-effect dependencies calculated with respect to the total concentration of toxic substances, standardized to MPC, and fish health criteria, cases that exceed the critical levels of pollutants are demonstrated for the investigated river sections.

Trace metal accumulation and fish pathologies in areas affected by mining and metallurgical enterprises in the Kola Region, Russia.

Throughout the Kola region of Russia there has been a substantial increase of metal concentrations in water, which are related to local discharges from metallurgical and mining industry, transboundary transmissions as well as indirect leaching of elements by acid precipitation. This study presents data on the levels of Ni, Cu, Sr, Al, Zn, Co, Mn, Pb, Cd, Hg in the organs and tissues of fish, and evaluates relationships with water chemistry. Special attention is paid to fish pathologies, whose aetiology is related to the accumulation of metals and the associated changes of the elementary ratios within the organism. Ecotoxicological assessment of the copper nickel, strontium and acidification regimes also is considered in this article. In general we observed a large number of lakes that are heavily contaminated by Ni and Cu. Fish in these lakes contain high concentrations of Ni and Cu and display frequent pathologies, mostly associated with the kidneys. In lakes contaminated with Sr, there also are high Sr levels in fish and pathologies associated with skeletal tissues. Exposure to acidified water appears to increase the transport of metals (including Al, Ni and Cu) into fish and hence the toxic effects.