David H. Shull and Eugene D. Gallagher, Ph.D.

Environmental, Coastal and Ocean Sciences Program
University of Massachusetts Boston
Boston, MA 02125

Capping of subaqueous dredged-material disposal areas is becoming a common method for isolating contaminated sediments from the environment. This paper presents two methods for determining how thick a sediment cap must be to isolate contaminants from the sediment reworking activities of organisms. Both methods use data on local benthic communities to make quantitative predictions of the minimum cap thickness necessary to isolate contaminated dredged material. For Boston Harbor, this thickness is about 50 cm.