Sixty percent of California’s public water supply wells that were tested for so-called forever chemicals contain those compounds, according to research that the State Water Resources Control Board released Wednesday.
That same investigation into contamination from per- and polyfluoroalkyl substances (PFAS) also found that groundwater and surface water sampled at airports far exceeded the concentrations detected in water near landfills and public supply wells.
The findings, which detail an ongoing sampling effort launched in 2019, shed new light on the presence of PFAS contamination and areas that could be vulnerable based on proximity to known sources like airports and landfills.
The PFAS sampling as part of the investigation, for instance, found concentrations of up to 1 million parts per trillion at airports, compared to 10,000 parts per trillion at landfills and 100 parts per trillion at public wells, according to the survey.
Other interesting findings: The size of airports had no impact on PFAS concentration levels. And at landfills, contamination was more concentrated in leaching from solids than in groundwater.
“For me, this is a stark reminder about source control,” board member Sean Maguire said. “Ideally we’re getting it out of the system in the first place and stopping it from spreading.”
The Southern California Alliance of Publicly Owned Treatment Works, which represents wastewater and water treatment agencies serving 15 million residents, said keeping the contamination out of the system is a preferred option over costly treatment.
“We can’t treat our way out of this problem,” Executive Director Steve Jepsen said Wednesday. “We need aggressive product stewardship.”
The state survey began with an initial look at airports, landfills, and water supply wells. Chrome-plating operations were added later. Bulk fuel terminals and refineries will begin reporting at the end of this year.
State officials say the data will help the state identify sources of PFAS and give a better picture of contamination so the state can set a drinking water standard, which is years down the line.
PFAS are a family of more than 6,300 man-made chemicals that are widely used in consumer products because they are grease-, stain-, and water-resistant. They’re also used in certain firefighting foams to control fuel fires because they envelope the substance, cutting off oxygen.
The compounds have become ubiquitous in water supplies across the nation, and California is no different.
Exposure can cause developmental issues in children, increase the risk of certain cancers, suppress the immune system, and can reduce the effectiveness of vaccines, according to a Centers for Disease Control and Prevention Agency.
The Environmental Protection Agency has a health advisory level of 70 parts per trillion combined for two PFAS, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).
California in February lowered its response levels—exceedances require wells to be treated, taken offline, or blended with other sources—to 10 parts per trillion for PFOA and 40 parts per trillion for PFOS.
More than 3,000 water samples have been take so far at 30 airports, 196 landfills, and 900 public supply wells as part of the investigation. The tests have detected PFOS, PFOA and seven other PFAS at the sites.
PFAS can be separated into short-chain and long-chain forms, which differentiate between the number of molecules present. Short-chain PFAS were more prevalent than long-chain PFAS in the sampling done by the state, but both types were present.
An ongoing question is how the state may set its drinking water standard and if it will be by individual compound or groups of similar compounds, known as a class. Board Chair E. Joaquin Esquivel said Wednesday that the grouping could be based on how the compounds can be removed or remediated.
A key way to address the contamination is to identify sources and prevent release into the environment, state officials say.
Last month, Gov. Gavin Newsom signed a bill banning firefighting foams containing PFAS. And the state toxics agency is also reviewing PFAS in carpets, rugs, treated textiles, and food packaging.