The chemistry and toxicity of sediment affected by oil from the North Capespilled into Rhode Island Sound

On 19 January 1996, the barge Nor tk Cape spilled more than three million l iters of No. 2 fuel oil into Rhode Island Sound near Matunuck, Rhode Island . The toxicity and chemistry of this oil in two subtidal sediments were fol lowed for more than 9 months. Maximum concentrations of polycyclic aromatic hydrocarbons (PAHs) in the sediments reached 730 mu g/g dry weight (DW), W ater samples taken immediately after the spill were phototoxic to embryos o f the bivalve Mulinia lateralis. Total PAHs and toxicity to the amphipod Am pelisca abdita were high immediately after the spill, decreasing to backgro und values (10 mu g/g DW and <20% mortality, respectively) after 6 months. Changes in toxicity to A. abdita related closely to changes of PAH concentr ations in sediments. Weathering and degradation of the oil were followed by using ratios of PAHs, and alkanes as indicators. To distinguish effects of local boat traffic from spill effects, these ratios plus distributions of PAHs in sediments from a nearby marina were used. (C) 1999 Published by Els evier Science Ltd.