Per- and Polyfluoroalkyl Substances (PFASs) in the Fountain Creek Watershed, Colorado Springs, CO, USA: A Yearlong Investigation of PFAS Levels in Water, Soils, and Sediments

Per-and polyfluoroalkyl substance (PFAS) contamination of water resources and impact on affected populations in the southern Colorado Springs metro area have been of research interest since initial reports were announced via local news outlets in 2016. In this study, surface water, soils, and sediments were collected monthly for a full year at eight locations within the Fountain Creek Watershed of Colorado Springs, CO, USA. Using a novel quantitative method, levels of nine PFASs were determined via liquid chromatography tandem mass spectrometry (LC/MS/MS). Mean levels of n-ary sumation 9PFAS in water were 71.4 ng/L (median 57.9 ng/L) and ranged from 18.1 to 172.3 ng/L. Using these data, logKow values, and % total organic carbon content, predicted levels of PFASs in soil and sediment samples were modeled. Actual concentrations via LC/MS/MS for PFASs in soils and sediments reflected previously reported metadata for solid samples affected by aqueous film-forming foam use and release. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were detected in most (>87%) soils and all sediment samples. Predicted vs actual concentrations (ng/gdw) of PFOS agreed extremely well for soil and sediment samples in this study, while agreement of predicted vs actual concentrations for PFOA was less robust. This latter observation motivated a follow-up study to assess whether, and to what extent, PFOA levels in affected at the sites.