Palos Verdes Shelf

Description and History

The Palos Verdes Shelf (PV Shelf) site is a large area of DDT- and PCB-contaminated sediment located in the ocean off the coast of the Palos Verdes peninsula near Los Angeles, California. The offshore site stretches from Point Fermin in the southeast to Palos Verdes Point in the northwest, a distance of about 15 kilometers. The shelf varies in width from approximately 1 to 6 km, begins in water depths of 30 meters and gently slopes to water depths of approximately 70 to 100 meters, where the shelf breaks. At the shelf break, the slope increases to 13 to 18 degrees, leading to the ocean floor at depths of over 800 meters.

DDT is present in the Palos Verdes sediments largely as a result of wastewater discharges from the former Montrose Chemical Corporation DDT manufacturing plant in Torrance, California, which operated from 1947 to 1983. Wastewater containing significant concentrations of DDT was discharged from the Montrose plant to local sewers and conveyed to the Joint Water Pollution Control Plant (JWPCP) owned and operated by the County Sanitation Districts of Los Angeles County. Wastewater from the JWPCP is discharged to the Pacific Ocean through submarine outfalls located off White Point on the Palos Verdes peninsula. It is estimated that over 1,700 tons of DDT were discharged by the JWPCP from the late 1950s to the early 1970s.

PCBs from several sources in the greater Los Angeles area were also discharged into the sewer system and released through the White Point outfalls. Much of the DDT and PCBs released through the outfalls settled out on the ocean floor along with the suspended solids and other contaminants in the JWPCP effluent, forming what is referred to as an effluent-affected sediment layer. The DDT- and PCB-contaminated sediment deposit covers portions of both the continental shelf (the Palos Verdes Shelf) and continental slope off the Palos Verdes peninsula and ranges in thickness from 5 centimeters (cm) to greater than 60 cm. The total volume of the effluent-affected sediment deposit is over 9 million cubic meters, with approximately 70% of this volume on the continental shelf (i.e., in water depths less than 100 m). In its 1994 report, the U.S. Geological Survey (USGS) characterized an area of 44 km2 (17 sq. miles) on the PVS with elevated levels of DDT and PCBs in surface sediments. Subsequent data showed that the effluent-affected DDT- and PCB- contaminated sediments covered a larger area, and EPA expanded the PVS study area to include sediments from Point Fermin in the southeast to the southern edge of the Redondo canyon, northwest of the Palos Verdes peninsula. EPA's evaluation of potential cleanup actions is focusing on the areas of highest contamination.

Historically, the waters of the Palos Verdes Shelf have been used extensively by both sport and commercial fishermen. Sport fishermen angle from party boats, private boats, rocky intertidal areas and sandy beaches. Other activities in this coastal area include boating, swimming, windsurfing, surfing, scuba diving, snorkeling and shellfishing.

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Contaminants and Risks

Sediments and Surface Water

The area of highest DDT and PCB contamination in sediment is located roughly 2 km offshore and extends westward from the outfalls approximately 5 km along the shelf. Because the most significant discharges of DDT and PCBs to the Palos Verdes Shelf ceased in the early 1970s, the most contaminated sediments have gradually been covered over, primarily by solids discharged through the outfalls and by solids eroded from the nearby Portuguese Bend landslide area. The depth in the sediment column to the maximum concentration of DDT is greater than 40 cm on parts of the shelf but is commonly less than 10 cm on the slope. The maximum concentration of DDT exceeds 200 ppm near the outfall pipes; concentrations in excess of 50 ppm extend up to 4 km to the west of the outfalls. The distribution of PCBs follows a similar pattern, although concentrations are about an order of magnitude lower than the DDT.

Currently, high levels of DDT and PCBs are found in the active biologic zone of the Palos Verdes Shelf sediments, and fish from the Shelf are contaminated with high levels of DDT and PCBs. Generally speaking, contaminant levels are highest in bottom-feeding fish such as the white croaker and are significantly lower in fish that live higher up in the water column. DDT levels in ocean waters over the site range from 0.6 to 15.8 ng/L, while PCBs range from 0.06 to 1.14 ng/L. These levels all exceed the California Ocean Plan standards for DDT and PCBs. DDT levels in samples from a reference station upcurrent from the Palos Verdes Shelf were 0.20 ng/L, while PCBs were not detected. While DDT and PCBs at the site do not pose a risk for swimming and other types of water contact recreation, they are present at unsafe levels in some fish.

California EPA’s Office of Environmental Health Hazard Assessment (OEHHA) has issued health warnings for consumption of certain fish off Palos Verdes and other Southern California sites because of elevated DDT and PCB levels. These have been included in the California sport fishing regulations since March 1992. In 1990, the California Department of Fish and Game closed commercial fishing of white croaker on the Palos Verdes Shelf and nearby areas due to health risks posed by DDT and PCB contamination. Commercial fishing for other species of fish is permitted. A 1997 study by Heal the Bay of contaminant levels in commercially sold white croaker raised serious questions about the effectiveness of the fishing ban in terms of both the area closed and enforcement of the ban. In 1998, the Department of Fish and Game established a bag limit for white croaker to address the concern that sport fishermen may be illegally selling their white croaker catch to markets.

Ecological risks are being evaluated for a variety of assessment endpoints, including the benthic macroinvertebrate community, demersal (bottom-dwelling) and pelagic (water column) fish, fish-eating birds, raptors (such as bald eagles) and marine mammals. The results to date indicate that existing concentrations of DDT and PCBs in sediments on the Palos Verdes Shelf continue to pose a risk to benthic organisms, to fish (particularly demersal fish) and to fish-eating birds and raptors.

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Who is Involved

This site is being addressed through Federal agency actions.

EPA's response actions are being implemented with funds from cash-out settlements with several parties, including Montrose Chemical Corporation of California, Aventis Crop Science USA, Chris-Craft Industries, Atkemix Thirty-seven Inc., Potlach Corporation, Simpson Paper Co., CBS/Westinghouse, and settling local government entities.

In August 1997, EPA issued a proposed rulemaking to formally include the Palos Verdes Shelf as part of the Montrose NPL site listing.

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Investigation and Cleanup Activities

In 1990, the federal and state natural resource trustees began a natural resource damage assessment for the Southern California Bight, which includes the Palos Verdes Shelf. Following a review of the Trustees' 1994 expert reports, EPA in July 1996 initiated a Superfund non-time critical removal action to evaluate the need for and feasibility of actions to address human health and ecological risks.

In July 1997, EPA completed the Screening Evaluation of Response Actions for Contaminated Sediment on the Palos Verdes Shelf. That document looked at several potential remediation technologies and determined that the most feasible response technology was in situ (in place) capping (possibly augmented by institutional controls). In March 2000, EPA completed the Engineering Evaluation/Cost Analysis (EE/CA) report for Palos Verdes Shelf that summarizes site risks and evaluates the potential response actions. Based on the EE/CA report, EPA issued a Proposed Plan (see Community Involvement section below) that recommended institutional controls (public outreach & education, monitoring and enforcement) as an initial response actions to address human health risks associated with the consumption of contaminated fish.

As part of the EE/CA report, the U.S. Army Corps of Engineers Waterways Experiment Station (WES) performed an evaluation of in-situ capping options for EPA. The WES report is available via their web site at http://el.erdc.usace.army.mil/elpubs/pdf/trel99-2.pdf . Based on the WES report, EPA conducted a pilot capping project in 2000 in a small area of the site to evaluate cap placement methods and short-term impacts of cap construction. The pilot project report can be viewed or downloaded at the following web site: http://libweb.wes.army.mil/Archimages/12579.pdf . See below to view the October 2002 fact sheet that summarizes the pilot capping project. In 2002, EPA concluded that cap construction would be technically feasible; however, additional studies were needed. In 2004, EPA conducted several data gap studies to better understand the sediment fate and transport and the stability of the cap. Once these data gap studies are completed, EPA will go forward with the Remedial Investigation and Feasibility Studies (RI/FS) to evaluate cleanup options to address long term risks associated with the site.

The natural resource trustee agencies are addressing restoration of natural resource damages through the Montrose Settlements Restoration Program (MSRP). The MSRP is responsible for planning and implementing restoration projects to benefit injured natural resources such as bald eagles and peregrine falcons, and to create improved recreational and subsistence fishing opportunities to offset the impairment of fishing caused by contamination present in sports fish caught off the coast of Southern California. MSRP project updates is available via their website site at http://www.darcnw.noaa.gov/montrose.htm.

EPA issued the Action Memorandum for institutional controls in September 2000 and it can be downloaded from Region 9's web page. The web address is www.epa.gov/Region9/superfund/pvshelf/ and is called "Region09: Cleaning up the Palos Verdes Shelf."

The institutional controls program has three major elements: public outreach and education, fish monitoring, and enforcement. The public outreach and education program is being implemented by EPA in collaboration with several federal, state and local agencies, environmental groups and community-based organizations. To facilitate coordination and cooperation among these entities, EPA created the Seafood Contamination Task Force (now known as the Fish Contamination Education Collaborative), which meets regularly to discuss implementation issues and activities. In addition, EPA and key stakeholders have been meeting for strategic planning of the Palos Verdes Shelf Institutional Controls Program. For more information on the Fish Contamination Education Collaborative is available on www.pvsfish.org.

The fish monitoring program involves sampling both fish in the ocean and fish in retail markets. The MSRP and EPA completed the ocean fish sampling program in July 2007. EPA utilized the data to update the risk assessments for the site. EPA and the public are currently awaiting the State of California to update the existing fish advisory based on the recent data. EPA continues to sample white croakers at local markets. The first phase effort started in 2004. Finally, EPA is working with the local county health departments on marketplace inspection. EPA will be working with the California Department of Fish and Game to enhance enforcement of the white croaker commercial fishing ban off Palos Verdes peninsula and the daily catch limit on white croaker for noncommercial anglers.

Institutional Controls Program Update as of December 2007

The Institutional Controls (ICs) program was put in place to address the significant human health risks associated with consumption of certain fish, in particular the white croaker, contaminated by the DDTs and PCBs in the sediment at the Palos Verdes Shelf (PVS) site. Below is an update of the three components of the EPA’s ICs program.

Ocean Fish Monitoring Update

The EPA and MSRP completed a comprehensive ocean fish sampling effort in July 2007 to assess current fish contamination levels in the Southern California coast area. The collected fish species were pacific barracuda, pacific (chub) mackerel, pacific sardine, yellowtail, opaleye, sargo, kelp (calico) bass, surfperches, rockfishes, California sheephead, barred sandbass, top smelt, half-moon, California scorpionfish (sculpin), white seabass, black croaker, white croaker, yellowfin croaker, jacksmelt, California corbina, California halibut, shovelnose guitarfish and queenfish. These fish were caught at designated locations from Ventura to Dana Point, mostly in the Los Angeles area. Approximately 1000 fish samples were analyzed for DDTs, PCBs, dieldrin, chlordane and mercury. The final report and fact sheet are available at www.epa.gov/region09/superfund/pvshelf.

The data collected will be used for the following purposes:

To update health advisories and commercial fishing bans: The EPA is working with appropriate California state agencies to examine the existing fish consumption advisories for Southern California marine waters and the ban of commercial fishing for white croaker near PVS. CalEPA-Office of Environmental Health Hazard Assessment (OEHHA) will use the collected data to update the existing sport fish consumption advisories and existing commercial catch ban area, as appropriate, for white croaker near the PVS.

To provide information for the RI/FS: The fish data were used to help estimate what levels of DDTs and PCBs in sediment would not pose a significant health risk to human health and the environment.

To determine restoration of lost fishing opportunities: The Natural Resource Trustees, through the Montrose Settlement Restoration (MSRP) program, are investigating several potential approaches to increase the availability of wholesome fish to catch along the coast of Southern California. The collected fish data will provide information for the MSRP to plan and conduct its restoration projects.

To provide public information: The ICs program will update the existing public outreach material with information from the OEHHA’s advisory update and white croaker commercial catch ban assessment.

Market Fish Monitoring

As part of Phase I of the market monitoring program, the EPA conducted sampling at local markets from July 2004 through January 2005. The purpose of the sampling was to evaluate whether contaminated white croakers from the PVS site are reaching local consumers through markets. The EPA completed 135 visits at 68 markets in the Los Angeles and Orange counties. The EPA was able to collect 30 white croakers at 6 markets, mostly on repeated visits. The DDTs and PCBs levels in those white croakers were still of concern. EPA is working with local county health departments to put in place white croaker market inspection and surveillance program.

Angler Survey

The EPA and the MSRP jointly implemented a “two phased” angler survey in the fall 2002 and summer 2003. In order for the EPA to implement an effective outreach program, updated knowledge of the communities and their fishing and fish consumption practices was critical. The focus of the study was on people who fish, for recreation or subsistence, in coastal waters from Point Dume in Los Angeles County to Dana Point in Orange County. The information from this study is being used to ensure that the targeted populations are effectively reached in a culturally appropriate manner. A total of 2,441 angler interviews were completed with 1,181 in Phase 1 and 1,260 in Phase 2. Interviews were conducted at piers, beach/banks jetties, private/rental boats and party/charter boats. The collected information has been used in designing the overall evaluation and strategies for the ICs program.

Public Outreach and Education Program (Fish Contamination Education Collaborative {FCEC}) Update

Currently, the EPA is its 5th year of full implementation of the public outreach and education program. The EPA created the FCEC, as a mechanism for drawing interested agencies, groups and community based organizations together to design and implement a community based outreach program to address the health risks from eating contaminated fish related to the PVS site.

The cornerstone of the FCEC is the partnership between federal and state government agencies, local health departments, community based organizations, and other local institutions. The goal of the program is to conduct education for the most affected populations, so they can make informed decisions about fish contamination issues. The outreach efforts have been conducted in English, Spanish, Cambodian, Chinese, Filipino, Korean, Vietnamese, Chamorro, Samoan, Marshallese and Tongan.

The current program focus is to measure risk reduction through the ICs program implementation. EPA, with assistance from all stakeholders, put together a draft roadmap for the Institutional Controls Program which outlines the numeric objectives and associated strategies and tactics for the program. The draft document is available at www.pvsfish.org.

Remedial Investigations/Feasibility Study Update

In 2000, EPA conducted a pilot capping study project over a small area of the PV Shelf site. Three 45-acre areas at different depths were capped with sand from two different areas, using different capping methods. Post-cap monitoring in 2002 showed that contaminant levels over the capped areas were comparable to uncapped areas. The post-capping report identified additional information that was needed to evaluate the potential viability of capping. The EPA conducted four studies to address these data gaps and to learn more about the site. The studies are described below:

1.) The geotechnical study consisted of collecting sediment cores and performing a sonar survey. The sediment cores were analyzed for erodibility and geotechnical properties, such as grain size, bulk density, and total organic carbon. These studies provide information about the sediments’ erosion potential and other sediment characteristics throughout the site. The final report is available under "Site Documents and Reports" on the following link: www.epa.gov/region09/superfund/pvshelf

2.) The large bioturbator study collected samples at 19 stations in the sediments to study the extent of sediment mixing caused by ocean-dwelling creatures, including large species that could burrow through a sand cap and/or mix sediment from the deeper, more contaminated areas, with the cleaner top sediment layer. The study provided an assessment of the extent of sediment mixing that occurs on the Shelf due to these species. The study found evidence of large bioturbators, especially in the northwest region of the site; however, the populations were low to average and were not responsible for the recontamination found on the caps. The final report is available under "Site Documents and Reports" on the following link: www.epa.gov/region09/superfund/pvshelf

3.) The resuspension study looked at one of the pilot caps placed in 2000. In 2001 the Los Angeles County Sanitation District collected sediment cores across the PV Shelf and noted that the peak concentration of contaminated sediment was closer to the surface along the edge of one of the pilot caps. This study took sediment cores across the cap to assess the extent to which cap placement may have displaced the upper layer of less contaminated sediment, thereby bringing the more contaminated layer closer to the surface. This study found evidence of sediment displacement, but was unable to gauge the extent of it. It appeared that the capping technique caused the displacement. The final report is available under "Site Documents and Reports" on the following link: www.epa.gov/region09/superfund/pvshelf

4.) The oceanographic study focused on learning more about the tides and currents around the PV Shelf. Equipment that measures currents, turbidity, temperature and other factors was anchored on the Shelf from February to July 2004. This study provided the EPA with additional data; however, it only captured one storm event, leaving unanswered questions about the magnitude and frequency of oceanographic processes that resuspend and transport PV Shelf sediment. As a result, EPA funded an additional oceanographic study that ran from December 2007 to April 2008. This study captured three major storms and collected data on ocean conditions that can be used in modelling sediment transport.

Remedial Investigation Report

These four studies were completed in 2004. Data analysis and report preparation took place in 2005. The geotechnical, sediment displacement and bioturbation reports have been finalized. A draft oceanographic data report has been prepared; however, as mentioned above, additional work is needed to determine if the effluent-affected deposit will erode. Nevertheless, information from these and earlier studies were used to prepare the Remedial Investigation (RI) Report. The RI Report (October 2007) has been finalized and a copy is posted on “Site Documents and Reports.” The RI Report discusses the nature and extent of contamination on the PV Shelf and the transport and fate of the contaminants. The RI report also discusses levels of DDT and PCBs that birds, animals, and people may be exposed to through consumption of fish and other creatures found on the PV Shelf.

Feasibility Study

The Feasibility Study (FS) built on the findings of the 2004 field studies and the Remedial Investigation Report. The FS analyzed cleanup strategies for the Shelf, including dredging, natural recovery, capping, and in situ and ex situ treatment. The FS determined capping and monitored natural recovery are the most feasible alternatives, i.e., most effective at reducing the human health and ecological risk posed by the site. The FS analyzes in detail three alternatives, including no action, using nine criteria required by law. The Feasibility Study is available on-line.

Proposed Plan/Record of Decision

EPA presented its Proposed Plan that includes the remedial cleanup alternatives evaluated, and identifies EPA’s preferred alternative for the PV Shelf site. The public comment period was from June 15 to July 15, 2009. Three public meetings were held from June 23rd through June 25th at the; Cabrillo Beach House in San Pedro, CA; Banning's Landing in Wilmington, CA; and Palos Verdes Library in Rolling Hills Estates, CA. The Proposed Plan was mailed to the Site's mailing list, sent to the information repositories and posted on the website. EPA also met informally with many interested stakeholder groups. Comments received through this period are included in the Record of Decision (ROD) under Responsiveness Summary. The ROD is a document that memorialize EPA's interim decision.

On September 30, 2009, the EPA signed an interim Record of Decision (ROD) that selected an initial remedial action for PV Shelf of capping, monitored natural recovery, and institutional controls.

EPA initiated its work on the Palos Verdes Shelf as a non-time-critical removal action and is implementing the institutional controls program under that authority. EPA continued with the evaluation of ecological risks and sediment cleanup activities such as capping under its remedial program authority. The cleanup decision will be documented in a Record of Decision, supported by the remedial investigation/feasibility study (RI/FS).

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Cleanup Results to Date

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Potentially Responsible Parties

Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.

On-line information about the PRPs for the site is not yet available.

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Documents and Reports

Administrative Records
		Removal Action
Fact Sheets
	10/01/97	Update on EPA's Investigation of Contaminated Sediments
	03/01/00	Palos Verdes Shelf Proposed Plan
	10/01/02	EPA Issues Report on Pilot Capping Project
	05/01/05	Site Update
	04/01/08	Remedial Investigation Report Completed; Feasibility Study Underway
	06/01/08	Overview
	06/05/09	EPA Announces Proposed Plan
Records of Decision
	09/30/09	Interim Record of Decision
Technical Documents
	11/01/03	Final Ecological Risk Assessment
	01/01/07	Cruise Report for the 2007-2008 Palos Verdes Moored Measurement Program Field Deployment

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Community Involvement

Public Meetings:

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Public Information Repositories

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Additional Links

The Fish Contamination Education Collaborative (http://www.pvsfish.org) is part of EPA's ongoing public outreach and education efforts to address risks associated with consumption of contaminated fish.

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Contacts

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