Impact of geochemical factors of aquatic environment on the metal bioaccumulation in fish

Conceptions of the influence of geochemical factors on the penetrating ability and bioaccumulation of elements in fish are systematized. Two mechanisms have been proposed to explain the element detoxication in fish: (1) binding of metals by low-molecular sulfur-bearing proteins (metallothionein) with subsequent withdrawal and (2) sequestering in specific granules. It was shown that the low-mineralized and acidified waters provide higher penetrating ability and more intense accumulation of most metals. Most of the elements are better-able to penetrate in fish as ions, however, the large concentrations of Hg are accumulated in form of methylmercury. Original data on the contents and distribution of the majority of toxic elements (Hg, Cd, and Pb) are reported for fish from the Kola North basins. It was justified that the polymetallic contamination of waters causes a decrease of essential elements in the functionally important organs owing to the pathological disturbances. Technogenic-hydrogeochemical anomalies were distinguished in the Kola region (copper-nickel, strontium, and acidified hydrochemical provinces) on the basis of the element abundance in fish and the development of endemic pathophysiological disturbances. The elevated contents of some elements, including toxic metals, in fish in the Volga Basin are used to distinguish the hydrogeochemical provinces in the Lower Volga (Sr-Cd-Al-Cr-Ni), Middle Volga (Hg-Zn), and Upper Volga (Mn-Pb) regions.