Heavy metal contamination in freshwater fish from the border region between Norway and Russia.

The contents of Cd, Cu, Cr, Hg, Ni and Zn in muscle, liver and gills were studied in whitefish, perch, pike, brown trout, burbot and vendace from three lake localities in a watercourse in the border region between Norway and Russia, in the vicinity of mining activity and several metallurgic smelters. The contents of Cd and Ni in fish tissue increased with increasing proximity to the smelters, whereas the other elements showed similar concentrations at the three localities. The recorded heavy metal concentrations appeared to be within the ranges reported for fish from other metal-contaminated lakes, and higher than comparable observations from unpolluted systems. The heavy metal concentrations were usually lowest in muscle and highest in the liver or the gills. Significant differences in metal concentration levels were found between different fish species, but Hg was the only metal where these species differences were possibly related to biomagnification. For the other elements, the concentrations generally appeared to be inversely related to the trophic level of the fish species.