What are PFAS, PFOA, and PFOS? Valley Water proactively tests for man-made chemicals

You may have heard about Per-and Polyfluoroalkyl Substances, better known as PFAS, recently in the news or even at the movie theater. PFAS are a group of man-made chemicals that have been widely used for decades in industrial applications and consumer products.

Two of the most extensively produced and studied of these chemicals are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Both chemicals are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. Their oil and water repelling properties can render any material treated with these chemicals oil, water and stain resistant. As a result, PFAS are found in many types of products like frying pans (e.g. Teflon), food packaging, stain and water repellants, clothes, furniture, carpeting and textiles.

Available studies suggest that exposure to PFAS can lead to adverse human health effects.

Because of their persistence in the environment, PFAS have the potential to accumulate in water supplies. The major sources of PFAS in water supplies are fire training/response sites, industrial sites, landfills, and wastewater treatment plants/biosolids.

The United States Environmental Protection Agency (EPA) and State Water Resources Control Board (State Board) have set health advisory levels for PFOA and PFOS in drinking water. These health advisory levels provide guidance for water suppliers and require certain actions, but there are currently no state or federal regulatory limits for PFAS in drinking water. State and federal lawmakers and regulators are moving toward stricter regulations and standards for PFOA and PFOS, and possibly additional PFAS compounds in drinking water.

To better understand the occurrence of PFAS, the EPA required large public water systems to test for various PFAS, including PFOA and PFOS, between 2013 and 2015. There were no detections of PFAS in groundwater or surface water in Santa Clara County as part of this testing.

The ability to detect these chemicals at even lower levels has evolved since the EPA-required sampling. Based on limited sampling conducted since then, PFOA and PFOS have not been detected in Valley Water’s imported water or treated water supplies.

The State Board continues to order testing of wells throughout the state for PFOA and PFOS to help inform potential drinking water standards. The first phase of mandated testing targeted wells near landfills or airports, or those with prior detections of PFOA or PFOS. Future phases will target other potential PFAS sources like industrial sites and wastewater treatment systems.

PFOS was found above the notification level in six water supply wells in San Jose, prompting the water retailer to discontinue use of the wells out of an abundance of caution. PFOA or PFOS have not been detected in any water supply wells at levels where the State Board recommends removing the water source from service (also known as the response level) in Santa Clara County.

In February 2020, Valley Water voluntarily sampled PFAS at 55 monitoring wells throughout Santa Clara County. None of the 55 wells tested are used for drinking water. These results and other available data indicate that PFOA and PFOS are not widely present above current State Board health-advisory levels.

Valley Water will continue to work with the State Board and with local water retailers to better understand the presence and potential sources of PFAS in local water supplies, and to act if needed to ensure a safe and reliable drinking water supply. To support this, we are considering additional monitoring and our water quality laboratory has recently obtained state accreditation to test for PFAS in drinking water.

We take our responsibility to provide safe, clean water and to protect local groundwater seriously. Valley Water and local water retailers use proven technologies and best practices to ensure drinking water delivered to businesses and residents meets or exceeds all state and federal drinking water standards.

If you have more questions on PFAS, you can check out the information from the Environmental Protection Agency at https://www.epa.gov/pfas/basic-information-pfas and also our FAQ at https://www.valleywater.org/your-water/where-your-water-comes-from/groundwater/groundwater-quality. The FAQ includes information about treatment options for PFAS.

This information was updated June 1, 2020.

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