Arsenic concentration and distribution in Chautauqua Lake sediments

In order to describe the occurrence and to investigate the sources of arsenic found in Chautauqua Lake sediments, 98 grab samples have been analyzed by neutron activation analysis. The arsenic concentrations were found to range from 0.5 to 58.75 ppm for 96 of the 98 samples with an overall average value of 22.10 ppm. The two other samples had concentrations of 140.0 and 306.0 ppm. High arsenic concentrations have been positively correlated with a decrease in the sediment particle size. Natural arsenic concentrations found in the soil and bedrock in the area do not explain the observed concentrations in the lake sediment. The increase in arsenic appears to be related to the spraying of sodium arsenite as an aquatic pesticide during the period 1955-1963. (T.G.)