Levels of PFAS in sewage sludge used as fertilizer can pose risks that sometimes exceed safety thresholds “by several orders of magnitude,” the agency said.
For the first time, the Environmental Protection Agency has warned that “forever chemicals” present in sewage sludge that is used as fertilizer can pose human health risks, saying in a study on Tuesday that, in some cases, the risks could exceed the agency’s safety thresholds “sometimes by several orders of magnitude.” The agency maintained, however, that the general food supply was not at risk.
A growing body of research has shown that the sludge can be contaminated with manmade chemicals known as per- and polyfluoroalkyl substances, or PFAS, which are used widely in everyday items like nonstick cookware and stain-resistant carpets. The chemicals, which are linked to a range of illnesses including an increased risk of cancer, do not break down in the environment, and, when tainted sludge is used as fertilizer on farmland, it can contaminate the soil, groundwater, crops and livestock.
Last year, The New York Times reported that 3M, which for decades has manufactured PFAS, found as early as 2000 that the chemicals were turning up in sludge samples from municipal wastewater plants across the country. In 2003, 3M told E.P.A. of its findings.
The E.P.A. has for decades encouraged the use of sludge from treated wastewater as inexpensive fertilizer with no limits on how much PFAS it can contain. But the agency’s new draft risk assessment sets a potential new course. If finalized, it could mark what could be the first step toward regulating PFAS in the sludge used as fertilizer, which the industry calls biosolids. The agency currently regulates certain heavy metals and pathogens in sewage sludge used as fertilizer, but not PFAS.
The Biden administration has tackled PFAS contamination elsewhere, setting limits on PFAS in drinking water for the first time and designating two kinds of PFAS as hazardous under the nation’s Superfund cleanup law. Those rules came after the agency said in 2023 that there is no safe level of exposure to those two PFAS.