Exxon Valdez oil spill restoration project final report

Auke Bay Laboratory (Juneau, Alaska)

We sampled subtidal and low intertidal sediments at eight locations in the northern Gulf of Alaska in July 1994 to determine the geographical and bathymetric distribution of oil from the Exxon Valdez oil spill in the subtidal region and compare oil concentrations with those in the low intertidal zone. Sediments were sampled near mean lower low water and at three subtidal depths in the 3-20 m range. The sediments were analyzed for hydrocarbons using gas chromatography/mass spectrometry. No Exxon Valdez oil was found in sediments from 0 m at assessment sites where the greatest mean intertidal concentration of total polynuclear aromatic hydrocarbons excluding perylene (79 k 16.4 ngg) was observed at Hallo Bay. One intertidal sediment sample from Tonsina Bay showed evidence of Exxon Valdez oil. A proportion (one half) of the subtidal sediment samples collected at one station (Windy Bay, 6-m depth) showed mean concentration of total polynuclear aromatic hydrocarbons excluding perylene in benthic sediments (138 k 28.8 ndg) occurred at 6 m at Windy Bay. Petroleum hydrocarbons at the 20 m depth were chiefly (47% of all 20-m assessment samples) from the "Katalla" source.

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