The nature and extent of heavy metal contamination was assessed using plant, earthworm, and clam bioassays in conjunction with soil sample analyses. The study site consisted of terrestrial uplands, transition zones and wetlands in both freshwater and brackishwater environments contaminated with arsenic, cadmium, copper, lead, zinc, and selenium as a result of uncontrolled discharges of chemical wastes. Test data from the bioassays were used in conjunction with soil chemical analyses to determine the specific areas of contamination and the need for remedial action. Laboratory plant and earthworm bioassay results and field clam bioassay results indicated potential migration of hazardous chemicals from soil into foodwebs associated with the site. Field collected mice confirmed bioassay test results and showed bioaccumulation of cadmium and lead in some of those areas implicated by laboratory bioassay test results. Bioassays gave a good indication of the nature and extent of chemical migration into foodwebs associated with the site.