Spatiotemporal patterns of PFAS in water and crop tissue at a beneficial wastewater reuse site in central Pennsylvania

Authors: MROCZKO, OLIVIA - Pennsylvania State University; PREISENDANZ, HEATHER - Pennsylvania State University; WILSON, CHRISTOPHER - Pennsylvania State University; ELLIOTT, HERSCHEL - Pennsylvania State University; Veith, Tameria - Tamie; MASHTARE, MICHAEL - Pennsylvania State University; Soder, Kathy; WATSON, JOHN - Pennsylvania State University

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2022
Publication Date: 11/3/2022
Citation: Mroczko, O., Preisendanz, H.E., Wilson, C., Elliott, H.A., Veith, T.L., Mashtare, M.L., Soder, K.J., Watson, J.E. 2022. Spatiotemporal patterns of PFAS in water and crop tissue at a beneficial wastewater reuse site in central Pennsylvania. Science of the Total Environment. 51(6):1282–1297. https://doi.org/10.1002/jeq2.20408.
DOI: https://doi.org/10.1002/jeq2.20408

Interpretive Summary: Numerous everyday products contain or are coated with chemicals, called per- and polyfluoroalkyl substances (PFAS), that create benefits such as water repellency, non-stick surfaces, and heat protection. These non-degrading chemicals, which pass through standard wastewater treatment facilities, are difficult to detect without advanced chemical analysis but have been shown to seriously impact human health and endanger other animals. This study collected water and crop tissue samples from a wastewater reuse site in Central PA called the "Living Filter" in addition to influent and effluent samples from the treatment plant providing the wastewater. Wastewater has been spray irrigated onto forest and crop land at the Living Filter since the 1960's as a means of natural filtration and reclamation. Analysis of the soil water samples showed that PFAS compounds were present in soil water throughout the Living Filter. However, PFAS concentrations were below health advisory levels and did not appear to change much over time. PFAS concentrations in crop samples suggested that the PFAS present at the site is taken up by the plants and thus can enter the food chain if used as forage.

Technical Abstract: Per- and polyfluoroalkyl substances (PFAS) are a collective name for a growing range of thousands of synthetic compounds produced to enhance both consumer and industrial products since the 1940s. These compounds are not easily degraded and pose serious ecological and human health concerns at trace concentrations (ng/L levels). PFAS persist in treated wastewater and therefore are inadvertently introduced into the environment when treated wastewater is reused as an irrigation source. The Pennsylvania State University has been spray-irrigating its treated wastewater at a site known as the “Living Filter” since the 1960s. The 2.45 km2 site is mixed use agricultural and forested land, with 13 monitoring wells that enable assessment of the potential impacts of this long-term wastewater irrigation on groundwater quality. To understand the spatiotemporal trends of 20 PFAS compounds at the Living Filter, water samples were collected bi-monthly from fall 2019 through winter 2021 from the University’s wastewater influent and effluent and from each of the 13 monitoring wells. Additionally, crop tissue was collected from irrigated and non-irrigated fields within the study site to assess PFAS presence in corn and tall endophyte-infected fescue grown at the Living Filter. Overall, data suggest that wastewater irrigation resulted in detectable PFAS concentrations across the Living Filter, with concentrations generally increasing with the direction of groundwater flow. Concentrations within each well varied little across sampling events, with coefficients of variation < 0.25. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were detected at levels below the health advisory levels (i.e., < 70 ng/L). Further, PFAS present in the crop tissues suggest that PFAS enter the food chain once those crops are fed to livestock, even when crops were not directly spray-irrigated with treated wastewater. This research provides insight into the potential impacts of long-term beneficial reuse of treated wastewater on groundwater and crop tissue quality.