ASSESSMENT OF SEDIMENT TOXICITY AND CHEMICAL CONCENTRATIONS IN THE SAN-DIEGO BAY-REGION, CALIFORNIA, USA

Sediment quality within San Diego Bay, Mission Bay, and the Tijuana Ri ver Estuary of California was investigated as part of an ongoing state wide monitoring effort (Bay Protection and Toxic Cleanup Program). Stu dy objectives were to determine the incidence, spatial patterns, and s patial extent of toxicity in sediments and porewater; the concentratio n and distribution of potentially toxic anthropogenic chemicals; and t he relationships between toxicity and chemical concentrations. Rhepoxy nius abronius survival bioassays, grain size, and total organic carbon analyses were performed on 350 sediment samples. Strongylocentrotus p urpuratus development bioassays were performed on 164 pore-water sampl es. Toxicity was demonstrated throughout the San Diego Bay region, wit h increased incidence and concordance occurring in areas of industrial and shipping activity. Trace metal and trace synthetic organic analys es were performed on 229 samples. Copper, zinc, mercury, polycyclic ar omatic hydrocarbons, polychlorinated biphenyls, and chlordane were fou nd to exceed ERM (effects range median) or PEL (probable effects level ) sediment quality guidelines and were considered the six major chemic als or chemical groups of concern. Statistical analysis of the relatio nships between amphipod toxicity, bulk phase sediment chemistry, and p hysical parameters demonstrated few significant linear relationships. Significant differences in chemical levels were found between toxic an d nontoxic responses using multivariate and univariate statistics. Pot ential sources of anthropogenic chemicals were discussed.