Concentrations of lead, cadmium, mercury, and copper in the crayfish (Pacifasticus leniusculus) obtained from a lake receiving urban runoff

Abstract

Commercially caught crayfish (Pacifasticus leniusculus) were placed in a municipal lake below a combined sewer overflow outfall and a storm drain outfall associated with elevated sediment metal concentrations. Abdominal muscle, viscera, and exoskeleton from each crayfish were analyzed for mercury, cadmium, lead, and copper. Crayfish metal concentrations for each sampling site were evaluated relative to unexposed samples from the commercial catch and samples held in the laboratory. Results indicated that 1) mercury accumulated in muscle tissue, highest cadmium concentrations were in the viscera, and highest lead concentrations were in the exoskeleton, 2) uptake of copper is well-regulated by the organism at non-toxic water concentrations, and 3) viscera concentrations of cadmium, lead, and copper tended to be higher and more variable than in muscle tissue. A significant correlation was found between body weight and muscle mercury concentration. Relative to allowable limits for metals in foods, there was not sufficient accumulation of any metal to indicate that a significant health hazard would result from consumption of these organisms. These data indicate that analysis of trace metals in various body parts ofP. leniusculus may be a useful biological indicator of trace metal pollution of freshwater lakes and streams.