The study is a continuation of research into the effects of sludge and industrial wastes on two dumping sites in the mid-Atlantic continental shelf waters off Delaware Bay. There are two basic effects of marine pollution, both of which are under investigation in this area. Short-term effects typically occur in the water column and primarily affect plankton and pelagic organisms immediately or shortly after actual dumping occurs. Long-term effects are more generally observed in the benthic communities. This specific study is concerned only with the benthic organisms and must distinguish between the natural seasonal and successional fluctuations from fluctuations resulting from dumping.