Organochlorine contaminants in fish from an arctic lake in Alaska, USA.

A wide range of organochlorine pesticides and polychlorinated biphenyls (PCBs) were measured in muscle tissue and livers of lake trout (Salvelinus namaycush) and Arctic grayling (Thymallus arcticus) from Schrader Lake in Arctic Alaska. Results confirm the long-range transport of these contaminants to a US Arctic freshwater system. The most abundant group of compounds in all tissues was composed of PCBs. Mean concentrations of the sum of a selected group of PCB congeners ranged from 3.2 ng/g in grayling liver to 22.8 ng/g in trout liver and from 1.3 ng/g in grayling muscle to 6.6 ng/g in trout muscle (wet wt.). The second most abundant group was composed of chlordane-related compounds. No significant correlations of organochlorine concentrations with fish weight or length were observed for the data set as a whole. There were marked differences in sigma PCB, sigma chlordane and p,p'-DDE concentrations between species. The biomagnification factors for these compounds are similar to ratios reported for other aquatic systems. Comparisons showed that contaminant concentrations in lake trout from Schrader Lake were similar to levels found in burbot and slightly higher than levels in whitefish reported in Canadian studies from the Mackenzie River Delta.