Offshore of the Palos Verdes peninsula, the contaminated Palos Verdes Shelf Superfund Site stretches nine miles from Point Fermin in the southeast to Redondo Canyon in the northwest.
Undersea sediments along the shelf contain 110 tons of the pesticide DDT and about 10 tons of polychlorinated biphenyls, PCBs, the agency says. The contaminated sediment at the Superfund site is too deep for direct human contact, but fish in the area contain levels of the toxics that pose risks to people and wildlife that eat them.
The EPA plans to cover the most contaminated sediment with a layer of clean material and strengthen the existing public outreach and education program, monitoring, and enforcement.
Community educators on a boat tour of the Palos Verdes Shelf hosted by Los Angeles County Sanitation District, June 2009. (Photo by Alfonso Montiel courtesy Cabrillo Marine Aquarium)
This strategy is expected to reduce DDT and PCB concentrations in fish by reducing the concentration of chemicals in the sediment, the agency said today.
"Signing this interim cleanup plan is a major milestone that puts the Palos Verdes Shelf Superfund Site on the road to remediation," said Keith Takata, Superfund director for the EPA’s Pacific Southwest region.
"The EPA will spend more than $50 million to cap the most contaminated sediment on the shelf, as well as continue the highly effective public outreach program to protect at-risk populations from consuming contaminated fish," Takata said.
The primary source of the DDT was industrial waste from the world’s largest manufacturer of the pesticide, the Montrose Chemical Corporation. The company manufactured the pesticide at its facility in Torrance, California from 1947 to 1982.
The Montrose plant discharged wastewater containing the now-banned pesticide into Los Angeles sewers that emptied into the Pacific Ocean by way of the outfall pipes at White Point on the Palos Verdes Shelf.
It is estimated that over 1,700 tons of DDT were discharged between the late 1950s and the early 1970s. Other industries discharged PCBs into the Los Angeles sewer system that ended up on the Palos Verdes Shelf via the outfalls.
DDT was banned from general use in the United States as of January 1, 1973 after the federal government determined the pesticide posed unacceptable risks to the environment and potential harm to human health.
Used as coolants and lubricants in electrical equipment, PCBs were banned by the EPA in 1979.
The EPA classifies both families of chemicals as a probable human carcinogens. The discharge of these chemicals ceased more than 30 years ago, but their impacts persist today.
In 1989, Comprehensive Environmental Response, Compensation, and Liability Act natural resource trustees determined that DDT and PCB contamination of the marine environment off the southern California coast, including the Palos Verdes Shelf, could result in significant damage to natural resources.
In June 1990, the federal government and the state of California filed suit on behalf of federal and state natural resource trustees as well as EPA and the California Department of Toxic Substances Control.
Litigation concluded in 2000, with $136 million from the settlements set aside to pay for restoration and remediation.
In March 2001, the court approved the last of the settlements providing funds to the EPA to respond to the ecological and human risks posed by the DDTs and PCBs, and to six federal and state natural resource trustee agencies to restore injured natural resources and compensate for the loss of the services they provide.
Yet, today, large amounts of DDTs and PCBs remain in ocean water and sediments, and certain fish, birds, and other wildlife continue to accumulate DDTs and PCBs in harmful amounts.
Historically, the waters of the Palos Verdes Shelf have been used by both sport and commercial fishers. 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.
People should avoid eating white croaker, also known as kingfish or tomcod, which has the highest contamination levels, the EPA warns. Consumption of other bottom-feeding fish, including kelp bass, rockfish, queenfish, black croaker, sheepshead, surfperches, and sculpin, should be limited.
The EPA has established the Fish Contamination Education Collaborative, which includes community organizations, to reach out to the public and educate anglers and ethnic communities about the potential dangers in consuming contaminated fish, and how to minimize the danger.
Copyright Environment News Service (ENS) 2009. All rights reserved.