Analysis of Lead in Freshwater Clams from the Embarrass River, Coles County, Illinois

Abstract

Twenty-two freshwater clams of various genera were collected by hand from two sites on the Embarrass River located at 240 meters and 400 meters downstream from the dam at Lake Charleston and at depths of .4 and 2.5 meters. Ten grams of gill tissue from each clam was prepared by furnace ashing, dissolved in 30 ml. of acid mixture and analyzed for lead content using an atomic absorption spectrometer. The average lead concentration for the clams was 3.60 ppm, while that of the ambient water was 0.33 ppm indicating that these local bivalves show a lead biocentration of about ten times. The levels of lead found, and the proximity of the sites to motor routes, suggest that lead from automobile exhaust fumes finds its way into the River