Dec. 19, 2000—The U.S. Department of Justice (representing the EPA and several natural resource trustee agencies) and the California Attorney General announced a $73 million settlement with Montrose Chemical Corporation of California, Aventis CropScience USA Inc., Chris-Craft Industries Inc., and Atkemix Thirty-Seven Inc., companies which either owned or operated DDT-manufacturing plants in Los Angeles County.
Along with the prior settlements in this case, there will be approximately $140 million that can be used by federal and state agencies to help rehabilitate natural resources and clean up DDT contamination on the offshore Palos Verdes Shelf. The EPA's pilot cleanup project is already underway.
From 1947 to 1983, the now-banned pesticide DDT was manufactured by the Montrose Chemical Corporation at its former plant near Torrance, California. The Montrose plant discharged wastewater containing DDT into Los Angeles sewers that empty into the Pacific Ocean off the Palos Verdes peninsula. These contaminated sewer discharges stopped in the early 1970s. The DDT manufacturing process also resulted in groundwater and surface soil contamination on and near the Montrose plant property.
Several other industries discharged PCBs, a group of toxic chemicals, into the Los Angeles sewer system. Much of the DDT and PCBs settled on the ocean floor to create a vast 17-square-mile contaminated sediment deposit. The current mass of DDT in sediments at the Palos Verdes Shelf site weighs over 100 metric tons, and the total mass of PCBs weighs over 10 metric tons. DDT concentrations in the ocean have been measured at nearly 100 times greater than the state's recommended safe levels for the protection of human health.
Ecological and Health Risks
High levels of DDT and PCBs continue to threaten the Palos Verdes Shelf marine environment. DDT and PCBs move from contaminated sediments into the water. They also enter the food chain through worms and microorganisms, which may be consumed by other marine life. DDT and PCBs accumulate in fish tissue, then harming fish-eating birds, marine mammals, and birds of prey that feed on both.
For people, eating DDT- and PCB-contaminated fish can increase cancer risks, harm the liver, and affect the central nervous system. Nursing infants whose mothers regularly consume the fish are also at high risk.
Historically, the waters of the Palos Verdes Shelf have been used extensively by both sport and commercial fishers. Sport anglers fish from boats and beaches in the area. The waters are also used for swimming, windsurfing, surfing, scuba diving, snorkeling and shellfishing.
Since 1985, fish consumption advisories and health warnings have been posted in southern California because of elevated DDT and PCB levels. Bottom-feeding fish are particularly at risk for high contamination levels. Consumption of white croaker (also known as kingfish or tomcod), which has the highest contamination levels, should be avoided. Consumption of other bottom-feeding fish, including kelp bass, rockfish, queenfish, black croaker, sheepshead, surfperches, and sculpin, should be limited.
Cleanup Approaches
In August 2000, the EPA began a pilot "in situ capping" project on a small area of the Palos Verdes Shelf. Clean sediment was deposited over a small portion of the contaminated ocean floor, providing a cap to isolate the contaminants and reduce the amount of DDT and PCBs transferred to the water and marine life.
The pilot project includes evaluation of short-term results and cap placement methods. The EPA will use the data from this project, along with other relevant information, to decide whether to propose full-scale capping as a cleanup action for the Palos Verdes Shelf site.
