Ecotoxicologic change at a remediated superfund site in San Francisco, California, USA

Lauritzen Channel is an industrial waterway adjacent to the former United H eckathorn facility in the inner Richmond Harbor area of San Francisco Bay, California, USA. Marine sediments at this Superfund site were dredged from late 1996 through early 1997 to remove the primary chemicals of concern: DD T, and dieldrin. This study assessed the Lauritzen Channel marine environme nt immediately before and approximately one year after the dredging of sedi ments. The study included chemical analysis of sediments, tissue concentrat ions of transplanted mussels, toxicity resting of sediment samples, and cha racterization of benthic community structure. Results indicated that sedime nt toxicity to bivalve larvae (Mytilus galloprovincialis) decreased in post remediation samples. but that toxicity to the amphipod Eohaustorius estuari us increased significantly. Assessment of benthos at this site suggested a transitional benthic community structure. In addition, postremediation sedi ments remained contaminated by a variety of organic chemical compounds, inc luding DDT, dieldrin, chlordane, polycyclic aromatic hydrocarbons, and poly chlorinated biphenyls. Tissue concentrations of DDT and dieldrin in mussels (M. galloprovincialis) were lower than those in preremediation samples. in dicating that although sediment concentrations of organochlorine pesticides : remained high, concentrations of these chemicals in the water column were reduced after dredging. This study demonstrates that the components of the site assessment were useful in determining effectiveness of the remediatio n activities.