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Chemical gradients in sediment cores from an EPA reference site off the Farallon Islands - Assessing chemical indicators of dredged material disposal in the deep sea

Marine Pollution Bulletin

By:
, , , ,
DOI: 10.1016/S0025-326X(98)00003-4

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Abstract

Heavy metal and organic contaminants have been determined in undisturbed sediment cores from the US Environmental Protection Agency reference site for dredged material on the continental slope off San Francisco. As expected, the concentrations are significantly lower than toxic effects guidelines, but concentrations of PCBs, PAHs, Hg, Pb, and Clostridium perfringens (a bacterium spore found in sewage) were nearly two or more times greater in the surface sediments than in intervals deeper in the cores. These observations indicate the usefulness of measuring concentration gradients in sediments at the San Francisco deep ocean disposal site (SF-DODS) where a thin (0.5 cm thick) layer of dredged material has been observed beyond the boundary. This thin layer has not been chemically characterized by the common practice of homogenizing over the top 10 cm. An estimated 300 million cubic yards of dredged material from San Francisco Bay are expected to be discharged at the SF-DODS site during the next 50 years. Detailed depth analysis of sediment cores would add significant new information about the fate and effects of dredged material in the deep sea.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Chemical gradients in sediment cores from an EPA reference site off the Farallon Islands - Assessing chemical indicators of dredged material disposal in the deep sea
Series title:
Marine Pollution Bulletin
DOI:
10.1016/S0025-326X(98)00003-4
Volume
36
Issue:
6
Year Published:
1998
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
443
Last page:
457
Number of Pages:
15