Distribution of Metal Species and the Assessment Their Bioavailability in the Surface Waters of the Arctic: Proposals for the Water Quality Standards

The paper deals with the vulnerability of surface waters in the Arctic to regional and global base-metal pollution fluxes, a problem whose solution requires specialized approaches to water quality assessment. The metals are shown to be contained in low-salinity waters of the northern territories mostly in ionic forms, which predetermines the high bioavailability of these metals for aquatic life. A model for calculating the ionic species of metals was developed on the basis of mathematical modeling of chemical reactions in natural waters. For 22 aquatic areas in the Kola Peninsula, concentrations of metals (Hg, Cd, Pb, Ni, Cu, Al, and Sr) and their speciation in the waters were calculated. The accumulation of metals in organs and tissues of the fish (as exemplified by whitefish) was studied at the same sites. The biogeochemical activity of metals was demonstrated to determine, first of all, the ratio of labile and nonlabile metal species in the water. The bioavailability of metal species was estimated depending on the geochemical parameters of the aquatic environment and the in-situ speciation of the metals, based on the results of original studies of local lakes. The relationships between the contents of metals in the fish and the content of metal species in the water are clarified using methods of multidimensional scaling and the RDA technology. Values are proposed for the maximum permissible concentrations (MPC) of metals with regard to their high bioavailability in northern low-salinity waters.