Impact of Contaminants Mobilized from Sediment Upon Disposal

Abstract

Contaminated sediments are often regarded as a nuisance, although not much is known about the effects of the contaminants on organisms exposed to them. High concentrations of contaminants in sediments are a general cause of concern. The problem becomes acute when large amounts of contaminated dredgings have to be disposed of. Harbor authorities worldwide are faced with the conflict between environmental concern on one hand and economical, feasible solutions on the other, a conflict that raises such questions as why and how sediments should be disposed of, what uses they can be put to, and how they should be treated (Tent 1984). Strangely enough we are far from answering the crucial questions in this context: whether the ecosystems living on top of contaminated sediments are “good” or “bad”, and whether disposal of contaminated sediments poses a threat to ecosystems elsewhere. Hardly any research has been done to answer these questions. This creates the incongruous situation where great efforts are being made towards solving the problem of transporting, confining and treating contaminated sediments when a sound ecotoxicological basis is lacking. This chapter summarizes and evaluates research attempting the basic question, whether, and if so, why, contaminated sediment poses a threat to the environment.