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Contaminated Sediment Off Palos Verdes, CA, the Subject of a Special Issue of Continental Shelf Research
The April/May 2002 issue of Continental Shelf Research reports the results of an interdisciplinary, USGS-led study of contaminated sediment off the Palos Verdes Peninsula, on the southeastern margin of the greater Los Angeles metropolitan area. During the 1950s and 1960s, the world's largest producer of DDT was connected to the Los Angeles County sewer system, which collects and treats wastewater that is then discharged through an ocean outfall just south of the Palos Verdes Peninsula. Significant quantities of DDT from the manufacturing plant entered the waste stream and were deposited on the Palos Verdes margin. Release of DDT waste from the manufacturing plant to the sewer system was stopped in the 1970s, and subsequent discharges from the outfall have deposited sediment with low levels of contamination above the highly contaminated deposit. However, biological, chemical, and physical processes have modified and partly mixed the sediment, introducing contaminants from the deeper part of the deposit into surface layers. Both benthic and pelagic organisms in the area have displayed elevated levels of DDT in their tissue. Reproduction of the brown pelican off southern California was severely reduced owing to egg-shell thinning caused by excess levels of DDT in tissue. Warnings against consuming White Croaker fish are still posted along the shores of the Palos Verdes Peninsula because of their high DDT content, and bald eagles continue to experience difficulties in reproduction owing to egg-shell thinning. Extensive studies of the contaminated sediment deposit were conducted by the Southern California Coastal Water Research project (SCCWRP), the Sanitation Districts of Los Angeles County (LACSD), and others through the 1970s and 1980s. In the early 1990s, a large, new research effort, led by the USGS, was undertaken off the Palos Verdes Peninsula in support of a lawsuit filed by the U.S. Department of Justice against the DDT manufacturer. Most of the papers in the special issue of Continental Shelf Research describe work conducted as part of this investigation. Edited by Homa J. Lee (USGS, Menlo Park, CA) and Patricia L. Wiberg (University of Virginia, Charlottesville), the special issue is entitled "Sedimentation Processes, DDT, and the Palos Verdes Margin." Its many authors include nine USGS scientists honored last summer by the Department of Justice for describing the nature and extent of the contamination, as well as its potential fate and transport, in support of the lawsuit against the DDT manufacturer (see article in August 2001 Sound Waves).
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in this issue:
Williams' Presentation on Videotape Caribbean Climate Change Conference Scientists Speak in Reston & D.C. Regional Geologist Visits WHFC Award-Winning Student Volunteer
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U. S. Department of the Interior | U.S. Geological Survey
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