Spatial and Temporal Patterns of PFAS Occurrence at a Wastewater Beneficial Reuse Site in Central Pennsylvania
By Mroczko, Olivia, Heather E. Preisendanz, Christopher Wilson, Tamie L. Veith, Michael L. Mashtare, John E. Watson, and Herschel A. Elliott
July 20, 2021
Per- and polyfluoroalkyl substances (PFAS) are a collective name for a growing range of synthetic compounds produced to enhance both consumer and industrial products since the 1940s. Due to their chemical composition, PFAS do not easily degrade and can accumulate within humans and the environment. As water quality detection technologies advance, PFAS are being classified as emerging contaminants because of the risks they pose to human health when present at sufficiently high levels in drinking water and crops. Because PFAS persist in treated wastewater, reusing treated wastewater as an irrigation source can introduce PFAS into agricultural fields. The Pennsylvania State University has been spray-irrigating its treated wastewater at a site known as the “Living Filter” since the 1960s. The site contains ~250 ha of agricultural fields and 13 monitoring wells. Water samples were collected from October 2019 to December 2020 from the wastewater influent and effluent, and from each of the groundwater monitoring wells and analyzed for 20 PFAS compounds. Additionally, crop residue samples were collected from irrigated and non-irrigated areas to assess PFAS build-up in corn silage and fescue resulting from PFAS in the irrigated water. Overall, data suggest that wastewater irrigation has resulted in detectable PFAS concentrations across the Living Filter, with concentrations generally increasing with the direction of groundwater flow. Concentrations varied little across sampling events but were inversely related to groundwater elevation. Further, PFAS present in the crop tissue suggests that PFAS may enter the food chain once those crops are fed to livestock. Research results provide insight into potential impacts of beneficial reuse of treated wastewater on groundwater and crop tissue quality.
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