EFFECTS OF PAST MINING ACTIVITIES ON THE ARSENIC CONCENTRATION IN FISH FROM MOIRA LAKE, ONTARIO

The effects of the past mining activities on. the arsenic (As) concentration in 14 species of fish from Moira Lake, Ontario, Canada, were determined The lake is characterized by elevated concentrations of As, with up to 106 mu g/L in water and 1,000 mu g/g in bottom sediments. The mean whole-body concentration of As in 13 of the fish species ranged from 0.03 to 0.34 mg/kg wet weight, whereas that for the creek chub (Semotilus atromaculatus) was 2.4 mg/kg. For rock bass (Ambloplites rupestris), concen- trations of As were greatest in the intestine, followed by the bones plus scales. The mean ratio for the liver:muscle As concentration in rock bass (0.53) suggests a relatively low level of As stress. Despite the elevated environmental concentrations of As, and with the exception of creek chub, the tissue residues of As suggest that Moira Lake fish are not under As stress. Moreover, the As concentrations in the fish do not seem to represent a health hazard to local residents that consume fish.