Presence of Perfluoroalkyl Substances in Landfill-adjacent Surface Waters: Case Studies in Orange County and Sampson County, North Carolina

Abstract

Background/Aim: Perfluoroalkyl substances (PFAS) are a synthetic class of compounds used in consumer products. Landfills have been identified as major sources of PFAS into the environment, though they are not commonly monitored in surface and groundwater near landfills in the US. This study characterized PFAS in surface waters adjacent to two landfills in North Carolina: one in Sampson County (SC) and another in Orange County (OC). The site in SC accepts PFAS-containing industrial sludge. Both sites are close to predominantly African-American neighborhoods. Landfills pose an important public health risk, especially in low-income communities and communities of color that are disproportionately sited for landfills and in rural areas where private wells may be impacted. Methods: Water samples were collected along surface water features near the landfills at points that were upstream, adjacent, downstream and downgradient. Samples were collected every 3 weeks between October 2019 and January 2020. Concentrations of thirty-four PFAS were measured using liquid chromatography with tandem mass spectroscopy (LC-MS) using the large volume direct injection method. A simple t-test was performed to determine if the average concentrations measured adjacent and downstream of the landfill were statistically significantly different from concentrations upstream of the landfill. Results: Across the 35 samples collected, we detected twelve PFAS (six novel and six legacy). Legacy PFAS were detected in surface water near both landfills, with concentrations most elevated at sampling sites adjacent to the landfill, compared to upstream sites. Novel PFAS were only detected in surface water near the SC landfill, with similar concentration profiles as the legacy PFAS. Conclusions: Offsite migration of leachate is the likely contributor of PFAS measured in landfill adjacent surface waters in SC and OC. These findings support the need for more comprehensive and more frequent water monitoring near landfills and stricter regulation regarding the landfilling of industrial materials.