A Threat from Below
State water officials ask the EPA’s Superfund program for “emergency assistance” to address toxic plume underneath Playa del Rey
By Gary Walker
Citing “potential substantial risks to human health,” the Los Angeles Regional Water Quality Board is requesting “emergency assistance” from both the U.S. Environmental Protection Agency’s Superfund Division and county health officials to evaluate and possibly clean up a toxic chemical plume underneath Culver Boulevard in Playa del Rey.
Last November, The Argonaut reported local concerns about toxins found to exist underneath the former Del Rey Dry Cleaners at 310 Culver Blvd. — specifically tetrachloroethene, trichloroethylene and vinyl chloride, potentially carcinogenic chemicals that the California Regional Water Quality Control Board describes as “contaminants of concern.”
Community organizers in Playa del Rey are worried that excavating nearby land for development could disturb the chemicals, pulling the plume closer to residential housing and the Ballona Wetlands Ecological Preserve.
The L.A. board is the regional arm of the state water board, and the U.S. EPA’s Superfund program is responsible for responding to environmental emergencies and cleaning up the nation’s most contaminated land.
Because the dry cleaning business no longer exists and the property’s new owners say they cannot afford to clean up the site, state and local officials are unable to identify a responsible party whom they can compel to remove the chemicals.
“We are seeking your financial and/or technical assistance to further characterize and/or mitigate the potential high human health risks to residents and others posed by subsurface VOC [volatile organic compounds],” state Water Quality Control Board Executive Director Samuel Unger writes in the letter to the EPA.
The EPA reviewed water quality board’s letter and recommended that they contact other local or state agencies, since these sites are regulated by the state, said agency spokesman Nahal Mogharabi.
“If local or state agencies are unable to address the site, either due to the size or scope of the problem, then EPA would look further into assisting the state,” Mogharabi said.
Health officials are concerned that the underground chemicals could impact human health if the plume spreads underneath buildings and contaminated groundwater vapor seeps up from the soil, a process the EPA describes as vapor intrusion. The primary concern about buildings with even low concentrations of toxic vapors is whether the toxins could increase health risks due to long-term exposure.
The EPA classifies tetrachloroethene, also known as perchloroethylene or PCE, as likely being carcinogenic to humans. The agency classifies vinyl chloride, often used in the production of polyvinyl chloride (PVC) plastics and vinyl, as a Class A human carcinogen. Constant exposure to the industrial solvent trichloroethylene has been shown to have adverse effects on the human nervous system.
The amount of hazardous chemicals underneath the former dry cleaners is considered unusually large for that type of site.
“Based on the levels of chemicals in the soil, they are of concern to us. It’s not common that you find these levels in the soil,” said Cyrus Rangan, director of the L.A. County Department of Health’s Bureau of Toxicology and Environmental Assessment.
Rangan said county heath scientists and members of the L.A. County Department of Public Works have conducted their own investigation of the site, an indoor modeling study to test the compound levels above ground and get a sense of how serious a threat vapor intrusion could be. An analysis of their findings is due out later this month.
“Based on some of our preliminary testing, the amount of chemicals that were found in the indoor phase was not close to what we found in the soil,” Rangan said. “But there still needs to be further testing of the soil to see if any mitigation is needed.”
That state water officials felt compelled to contact the EPA’s Superfund Division shows that they consider the potential groundwater hazards and the possibility of vapor intrusion to be serious, said Rachel Adams, a professor of environmental and civil engineering at Loyola Marymount University.
“Most sites where underground chemicals are found usually don’t have the potential to become Superfund sites,” Adams said.
The potential hazards posed by the toxic plume are complicated by plans for new residential construction in the area. Not far from the former dry cleaner, developers the Legado Companies hope to build a large apartment complex at 138 Culver Blvd., a property known as Jake’s Lot.
Hydrologists and Playa del Rey residents worry that the toxins under the former dry cleaner could spread if Legado begins pumping groundwater from Jake’s Lot in order to construct a two-level subterranean parking garage.
“Because the water table is so shallow, [Legado] has to de-water the site through pumping or drainage, and lowering the water table will create a greater driving force for moving the contaminants” toward the new structure, said Steven Deverel, a hydrologist who was hired by a group of concerned residents who later formed the Playa del Rey Guardians Society.
The nearby Ballona Wetlands could also be impacted if the toxins move west due to water removal through pumping, according to Deverel.
“Site de-watering may alter the groundwater hydrology at the Ballona Wetlands, which in turn may result in altered water quality and changes in water levels in the marsh habitat,” Deverel wrote. “Specifically, shallow groundwater levels can be lowered at the wetland. This may in turn affect the salinity of the wetland by drawing water of different quality (e.g. salinity) into the wetlands.”
LMU’s Adams said it would be difficult to identify the exact underground footprint of the toxic chemical plume and whether it may have moved into the groundwater stream.
Removing the chemicals would also represent a significant challenge.
“Groundwater is tough to remediate. The ‘pump and treat’ method tends to be very time-intensive and not very easy, and it can be quite expensive,” Adams said.