OCCURRENCE AND DISTRIBUTION OF PER- AND POLYFLUOROALKYL SUBSTANCES IN JURUPA COMMUNITY SERVICES DISTRICT

Per- and polyfluoroalkyl substances (PFAS) are increasingly detected in surface water and groundwater, which serve as a primary source of drinking water. Due to their persistence and potential risk to human health, many water utilities have implemented PFAS remediation technologies without fully delineating the extent of PFAS contamination, trends, and vulnerabilities under extreme climatic conditions. This study assesses the occurrence and distribution of PFAS in the Jurupa Community Services District (JCSD) using data from multiple years of groundwater monitoring. Spatial distribution and temporal trends were analyzed across multiple groundwater wells that serve as drinking water sources for JCSD. Statistical analysis was conducted using the US EPA’s ProUCL software to assess trends in PFAS concentrations in time-series data. Results indicate that naturally recharged wells exhibited compound-specific behavior, with some PFAS showing increasing, stable, or decreasing trends, reflecting inherent differences in chemical properties and subsurface geochemical conditions. Overall, PFAS concentrations trend upward over time, attributed to underlying hydrological mechanisms. Among the six PFAS for which National Primary Drinking Water Standards exist, five PFAS, perfluorobutane sulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS), were consistently detected. Although GenX was not observed in any groundwater samples. These findings underscore the need for comprehensive, site-specific characterization of PFAS sources and hydrogeologic controls before selecting remediation technologies.