Distribution of Per- and Polyfluoroalkyl Substances in the Rapidly Urbanizing Arroyo Colorado Watershed, Texas

This study presents the first report of per- and polyfluoroalkyl substances (PFAS) in water samples collected in the Arroyo Colorado (n = 15), irrigation canals (n = 6), stormwater and wastewater retention ponds (n = 7), as well as drinking waters (n = 2) across the Arroyo Colorado watershed. Of the 30 PFAS monitored in this study, 14 were detected in the samples in various combinations. Short-chain PFAS (less than 8 carbon atoms) were observed in most samples. Water collected from the Arroyo Colorado showed significant spatial variabilities, with high total PFAS concentrations observed near possible point sources - a municipal airport and wastewater treatment facilities. PFAS concentrations were generally higher in water samples collected in stormwater and wastewater retention ponds than in the Arroyo Colorado and irrigation canals. PFAS in stormwater retention ponds likely came from roadway runoff. Short-chain PFAS were observed in the two municipal water samples, but they were below the current U.S. EPA regulation limits or are not currently regulated. This study provides useful information for water quality in this region and provides insights into PFAS occurrence in a rapidly urbanizing area.