science
Study Finds PFAS Pesticides in California Surface Water and Sediment
The Environmental Working Group reviewed state and federal test data from 2020 to 2024 and reported PFAS detections in multiple agricultural counties. Nearly half of surface water samples and over half of sediment samples contained bifenthrin.
May 29, 5:01 PM·1m read1 source
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U.S. Geological Survey between 2020 and 2024. The review covered Butte, Colusa, Imperial, Merced, Monterey, San Luis Obispo, Santa Barbara, Stanislaus, Sutter, and Yolo counties. Nearly half of all surface water samples and more than half of all sediment samples contained bifenthrin, a PFAS pesticide.
Detections exceeded 80 percent of surface water samples in San Luis Obispo and Stanislaus counties.
Health and Regulatory Context The U.S.
Environmental Protection Agency has stated that researchers have not determined how long PFAS components take to break down. A 2024 National Library of Medicine study noted limited research on widespread PFAS exposure and its effects on the immune system.
In February the EPA reported that drinking water for at least one in seven Americans contained unsafe PFAS levels, with multiple California systems affected. On May 18 the EPA announced plans to rescind and restart regulation of certain PFAS chemicals, citing procedural issues from the prior administration.
Little, California legislative director for the Environmental Working Group, called for a swift phase-out of PFAS pesticides in agriculture and announced support for Assembly Bill 1603. The bill seeks to ban the use, sale, and manufacture of PFAS pesticides on crops by 2035.
As of May 29 the bill had completed its first reading in the California Senate. 5 million pounds of PFAS pesticides annually, according to the Environmental Working Group.
