Publication Summary

Since 1980, metals concentrations in water and sediments in the Claypit Pond vicinity in Whatcom County, Washington, have been found to intermittently exceed background concentrations. One potential nearby source is a municipal-sized incinerator and ash dump. To gain an understanding of contemporary as well as historical heavy metal levels in the Claypit Pond, sediments were sampled for heavy metals in June 1988.

Since 1980, metals concentrations in water and sediments in the Claypit Pond vicinity in Whatcom County, Washington, have been found to intermittently exceed background concentrations. One potential nearby source is a municipal-sized incinerator and ash dump. To gain an understanding of contemporary as well as historical heavy metal levels in the Claypit Pond, sediments were sampled for heavy metals in June 1988. Concentrations of copper, chromium, and zinc in sediments in Claypit Pond and the associated drainages are significantly elevated with respect to nearby reference areas. Copper concentrations range from 25 to 99 ppm (dry weight), chromium 69 to 740 ppm, and zinc 72 to 813 ppm. Concentrations of arsenic, nickel, and mercury were also examined. Compared with other freshwater and marine environments, chromium concentrations are very high. Even after some of the potential confounding effects of variations in overall surface area of sediments (measured by percent clay and percent total organic carbon) are accounted for, the concentrations of chromium in sediments near claypit Pond are still substantially above those from reference areas. The potential biological effects of these high concentrations of metals in sediments should be evaluated through measurements of benthic infaunal diversity and bioassay responses to sediments. Collection and analyses of sediment cores from the pond may help to determine how contemporary metals sources compare with historical contaminant loads.