Most chemical contaminants entering the marine environment eventually accumulate in sediments and, thereby, potentially render the sediments toxic to benthic and demersal organisms. Through deposition, adsorption, diffusion, resuspension, and emigration, sediments serve as both a sink and source for toxic contaminants in the marine environment. The relationship between the concentrations of chemicals in sediments and in the tissues of benthic biota is well established. Although the linkage between bioaccumulation and toxicological responses is poorly documented, logic indicates a strong association. Chemical contaminants in sediments have been implicated as the cause of the abnormal pathology observed in benthic and demersal organisms and the alterations in the structure of benthic invertebrate populations and communities. (Copyright (c) 1992 by Lewis Publishers, Inc.)