Bioassay and biomonitoring assessments of contaminant mobility from dredged material

The Clean Water Act in the United States requires that the environmental evaluation of dredged material prior to its discharge must include the effects of the proposed disposal environment on the bioaccumulation of contaminants in the food chain. Although the total amount of contaminated material is relatively small when the national dredging program is considered, a significant effort is expended to ensure that, through the application of predictive tests prior to dredging, the contaminated material is deposited in a manner that will result in minimum contaminant mobility. There also has been a necessity to conduct studies and develop management plans in relation to the potential movement of contaminants at disposal sites constructed before the hazardous nature of many contaminants were known. Three case studies illustrate some of the bioassay and biomonitoring procedures currently being applied by the Corps of Engineers.