METAL CONCENTRATION IN THE GILL, GASTROINTESTINAL-TRACT, AND CARCASS OF WHITE SUCKERS (CATOSTOMUS-COMMERSONI) IN RELATION TO LAKE ACIDITY

Adult white suckers were collected from four lakes in Maine that range d in pH from 7.0 to 5.4. The gastrointestinal tract and remainder of t he carcass of fishes of similar age and size from each lake, and gills from additional fishes of similar size, were analyzed for Al, Cd, Pb, and Zn. Carcasses were also analyzed for Hg. Concentrations of Al, Cd , and Pb were highest in the gastrointestinal tract and lowest in the carcass; Zn concentration was highest in the gill. For carcass, all me tals except Al differed significantly among lakes, for gill tissue Cd and Pb differed, and for gastrointestinal tract, only Cd differed amon g lakes. Where differences were significant, patterns among lakes were similar in each tissue analyzed. Concentrations of Cd, Hg, and Pb wer e negatively correlated with lake water pH, acid neutralizing capacity (ANC), Ca, and lake:watershed area, and positively correlated with la ke water SO4, indicating that concentrations were higher in fish from more acidic lakes. Zinc concentrations in gills were unrelated to lake acidity, and carcass concentrations were higher in the less acidic la kes, which is the opposite of the pattern for the other metals studied . Zinc in gastrointestinal tract did not differ among lakes. Although the lakes we studied were located in undisturbed watersheds and did no t receive any point source discharges, fish metal concentrations were comparable to or higher than those reported from waters receiving indu strial discharges.