SEDIMENT QUALITY ASSESSMENT STUDIES OF TAMPA BAY, FLORIDA

A survey of the toxicity of sediments throughout the Tampa Bay estuary was performed as part of the National Oceanic and Atmospheric Adminis tration's National Status and Trends Program. The objectives of the su rvey were to determine the spatial extent and severity of toxicity and to identify relationships between chemical contamination and toxicity . Three independent toxicity tests were performed: a 10-d amphipod sur vival test of the whole sediments with Ampelisca abdita, a sea urchin fertilization test df sediment pore water with Arbacia punctulata, and a 5-min Microtox(R) bioluminescence test with solvent extracts of the sediments. Seventy-three percent of the 165 undiluted sediment pore-w ater samples were significantly toxic relative to reference samples wi th the sea urchin fertilization test. In contrast, only 2% of the 165 samples were significantly toxic in the amphipod tests. The causes of toxicity were not determined. However, concentrations of numerous trac e metals, pesticides, poly-chlorinated biphenyl (PCB) congeners, polyc yclic aromatic hydrocarbons (PAHs), and ammonia were highly correlated with pore-water toxicity. Concentrations of many substances, especial ly total dichlorodiphenyltrichloroethanes (DDTs), endrin, total PCBs, certain PAHs, lead, and zinc, occurred at concentrations in the toxic samples that equaled or exceeded concentrations that have been previou sly associated with sediment toxicity.