EPA begins groundwater remediation project for DDT superfund sites

The Del Amo Pits and Montrose Superfund Sites ground water remediation project was the subject of a federal Environmental Protection Agency community meeting in Harbor Gateway in February. The properties are located between Normandie and Vermont north of Torrance Boulevard in an area of Los Angeles known as the Harbor Gateway.

The EPA describes the site contamination this way: “Montrose Chemical Corporation of California (Montrose) manufactured the technical grade of the pesticide DDT (dichloro-diphenyl-trichloroethane) from 1947 until 1982 at a plant located at 20201 Normandie Avenue. The 13-acre former plant property is located in the Harbor Gateway, a narrow half-mile-wide strip of land extending southward from Los Angeles proper to the Los Angeles Harbor.”

“These pathways included, but were not limited to, releases of non-aqueous phase liquid (NAPL) and wastewaters to the ground, releases to the storm water drainage pathways, discharge of hazardous substances to sanitary sewers and to the Pacific Ocean, aerial dispersion of DDT dust, and disposal of DDT in soil fill materials.”

According to EPA documents, Montrose was dumping up to 56,000 gallons a day of liquid chlorobenzenes into the Palos Verdes Landfill between 1970 to 1980. The L.A. County Sanitation District Permit 1487 approved Class I landfill disposal.

Air quality issues

When questioned about providing the air quality studies for air dispersion overtime and human health risks, the EPA said they have not yet put the pieces together to give an answer regarding exposure to any air quality issues. The EPA declared the site a Superfund site in 1989 and has been studying it before and since that time. The agency explained, however, that the chemicals being remediated are vaporizing up through the ground.

The Del Amo site operated from 1943 until 1972 as a center of large-scale industrial activities from synthetic rubber production during World War II. Owned by the U.S. government, the 280-acre operation consisted of a styrene plant operated by Dow Chemical Co., a butadiene plant operated by Shell Oil Co., and a synthetic rubber plant operated by U.S. Rubber Co., Goodyear Tire & Rubber Co., and others. In 1955, the U.S. government sold all three plants to Shell Oil.

While in operation, Montrose dumped DDT sediments in sanitary sewers. The sewers flowed into the Joint Water Pollution Control Plant (Carson, owned/operated by Los Angeles County Sanitation District) and then into the Pacific Ocean at the White's Point Outfall. Sediments on the ocean floor of the Palos Verdes Ocean shelf are contaminated with DDT. The Palos Verdes ocean waters are declared a Superfund Site due to the high levels of DDT left by this dumping.

Clean up to begin

The EPA is about to embark upon a Groundwater Cleanup Project. Chemicals involved in the clean up action are benzene, TCE, DDT, and chlorobenzenes.These chemicals in the groundwater were caused by the operations at the Montrose Chemical plant and the Synthetic Rubber Plant now known as the Del Amo site. Other near by industries chemical contamination must also be cleaned up.

The contamination has spread to an area more than a mile long and about a mile wide. The project will require a total of 22 wells; 14 to extract the water and 8 to re-inject the water. Eleven of the 22 wells have already been completed; an additional 11 wells will be dug as part of this groundwater project.

Construction is scheduled to begin March 18 on wells that will be dug in the streets in front of homes. Many residents at the meeting shared concerns about this operation. Installation of wells and pipelines will take place on public and private property. Pipes carrying contaminated water will be sent to a treatment plant. The pipes will be buried in trenches under neighborhood streets. Roads may be shut down at times to complete the project.

Kevin Mayer, EPA project manager, told the audience that the project will pull up the contaminated waters from the wells to remove the chlorobenzene, benzene, and TCE and return the cleaned water back into the ground through other wells. Soil removed from the trenches will be stored at the former Montrose property. Waters will be cleaned in an air stripping process. Activated carbon filters will absorb contaminants.

“Systems are expected to operate for another 40 to 70 years to clean up the entire site,” according to an EPA handout for the air stripping process. For more information, call the EPA Technology Branch at (703) 603-9910.

Check out this map for a location and update on the project.

Joan Davidson is a member of the Sierra Club South Bay Open Space Task Force. You can reach her at  j135cooper@yahoo.com. Photo of EPA and Shell Oil Co. recently started construction at the Del Amo site. Credit: EPA