EPA finds no PFAS in 10 pesticides

The US Environmental Protection Agency did not find any per- and polyfluoroalkyl substances (PFAS) in 10 pesticides, 6 of which were previously reported to contain low parts-per-million levels of perfluorooctanesulfonic acid (PFOS). The results in question were published last year by researchers at Texas Tech University and the US Department of Agriculture (J. Haz. Mat. Lett. DOI: 10.1016/j.hazl.2022.100067). The sample-preparation method used in that study involved solvent dilution, which could have led to erroneous results, the EPA says. The agency suggests that the researchers may have multiplied background levels of PFOS by a large dilution factor, which would result in an overexaggerated concentration or false-positive identification. The EPA developed an extraction method that it says is a more appropriate preparation method than solvent dilution for pesticides containing nonvolatile oil and nonionic surfactants. The agency obtained samples of the 10 pesticides from the study authors and also purchased 4 of the products in the marketplace. When using its new extraction method, the EPA did not find any of 29 targeted PFAS, including PFOS, above the detection limits in any of the samples.