The authors understanding of the effects of contaminants on benthic organisms lags well behind that for water column species because of the way in which sediments mediate bioavailability and because test protocols using infaunal organism are still in the developmental stage. Although quantitative analyses of benthic communities continue to be a primary assessment tool, their interpretation as to contaminant effects remains difficult, especially under conditions of moderate contamination. It is, therefore, important to determine how sediment contaminants affect lower levels of biological organization.