In response to questions about whether perfluoroalkyl and polyfluoroalkyl substances (PFAS) in water can get into the plants we eat, the Wisconsin Department of Health Services has issued a memo recommending that people do not use water that contains PFAS concentrations greater than 70 parts per trillion (ppt) for gardens. The 70 ppt threshold is the equivalent of EPA’s health advisory level for PFOA and PFOS in drinking water.
PFOA and PFOS are two of the most-studied PFAS chemicals however thousands exist. PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals have caused tumors in animals, according to the EPA.
“We have been researching the health effects of PFAS given the ongoing investigation into groundwater contamination in the Town of Peshtigo and City of Marinette from Tyco Fire Training Facility,” wrote senior toxicologist Robert Thiboldeaux, PhD. “Some plants concentrate PFAS slightly above what is in groundwater. Many other plants take up very little PFAS from water. Overall, the available research indicates that most garden plants are not a major source of exposure, but we cannot say there is no exposure.”
This spring, Tyco tested 129 residential wells for a limited number of PFAS compounds. Of the 129 homes tested, 23 homes had PFAS contamination below the federal advisory level of 70 ppt and one home was above.
Following the release of these test results, CSWAB contacted WDNR objecting to the limited scope of residential well testing when compared to on-site analysis. Residential wells were tested for only 6 PFAS compounds when as many as 19 PFAS compounds were detected in groundwater at the nearby Tyco site. As a result, the true number of affected homes may change when residential wells are appropriately tested.