Results from the first phase of sampling drinking water supply wells for per- and polyfluoroalkyl substances (PFAS) were recently published by the California State Water Resources Control Board (State Water Board) and show reportable levels at approximately 190 or 35% of the 570 wells tested. The State Water Board’s initial testing program focused on wells near commercial airports and municipal solid waste landfills. Of the 570 drinking water supply wells sampled, only four percent were above the response level (RL) of 70 parts per trillion (ppt) for perfluorooctane sulfonic (PFOS) and perfluorooctanoic acid (PFOA), the two most common PFAS compounds tested. Sixty-five percent of the wells sampled were below the notification levels set for PFOS and PFOA, 6.5 ppt and 5.1 ppt respectively. The results thus far are good news for many public water systems, as they show more than half of the wells tested are largely free of PFOA and PFOS. For those public water systems with supply wells impacted above the RL, and for the neighboring airports, the State Water Board will be requiring additional sampling to identify sources contributing to PFAS in the impacted wells.
The initial PFAS test results are from the first wave of sampling ordered by the State Water Board. In March 2019, the State Water Board announced a sweeping investigation to study and sample potential sources of PFAS in drinking water supplies from a variety of industrial and municipal sources of PFAS, including airports, landfills, manufacturing facilities, bulk terminals, and wastewater treatment facilities. PFAS are highly fluorinated manmade compounds that are resistant to heat, water and oil. They are used in fire suppression foams and in a wide range of products designed to be waterproof, stain-resistant or non-stick, such as carpets, furniture, cookware, clothing and food packaging. PFAS have been found in drinking water supplies and are reported to have a variety of adverse health effects.
Phase one of the State Water Board’s PFAS investigation focused on sampling and testing for PFAS in drinking water wells near airports where fire training or fire response sites may have used fire retardant foam containing PFAS and near municipal solid waste landfills. The results indicate that 369 wells tested below the current notification levels for PFOA and PFOS, 178 tested between the notification levels and the RL, 11 sampling sites tested between the RL and 100 ppt, and 12 tested over 100 ppt.
Public water systems with wells testing above the RL must now consider whether to take the well out of service or provide treatment if available. Public water systems with wells above the notifications levels for PFOA and PFOS are encouraged to report this information to customers.
Testing results show that while PFAS are present in California drinking water wells, thus far only a small percentage of wells have PFAS above the recommended health advisory level of 70 ppt.
What’s Next?
When the State Water Board announced its investigation in March, it announced that it would issue a second wave of orders under the PFAS sampling program. Phase Two focuses on testing at chrome plating facilities, refineries, bulk storage fuel terminals, and non-airport fire training locations.
Separately, the State Water Board also has indicated that it will publish groundwater testing results in areas known to have had PFAS and PFOA contamination such as airports and landfills by the end of the year. In addition, early next year the State Water Board plans to publish sampling data from federal facilities such as military bases where flame retardant foam containing PFAS may have been used.
In the regulatory arena, the Office of Environmental Health Hazard Assessment (OEHHA) is developing a public health goal (PHG) for PFOA and PFOS. This is an important step in the process to establish a maximum contaminant level (MCL), a regulatory standard for drinking water that a public water system must comply with and could be used as a groundwater remediation goal for sites with PFAS contamination. The development of a PHG and MCL could take at least a year.
The impact of PFAS on California drinking water systems, including health effects and costs of treatment and remediation remain to be seen. Litigation has yet to be filed in California because of PFAS contamination. But as more testing is conducted, more PFAS are likely to be found in groundwater and in drinking water supply wells. As a result, there will be a significant push to identify sources for PFAS and litigation will likely follow for the costs of investigation, treatment and remediation.
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