Per- and Polyfluoroalkyl Substances (PFAS) and Co-occurring Contaminants in the Fraser River, a Headwater Tributary to the Colorado River - September 2021 to August 2023

The Fraser River, located in the Colorado Rocky Mountains, is a headwater tributary to the Upper Colorado River. This investigation by the U.S. Geological Survey (USGS) Water Mission Area, Water Quality Processes Program Proxies Project was conducted from September 2021 through August 2023 and consisted of eight sampling events incorporating 17 sites (15 stream sites and two wastewater treatment plant effluents) along a longitudinal transect of the Fraser River from the Continental Divide to the confluence with the Colorado River. Field measurements, water-quality samples, and streamflow measurements were collected at approximately quarterly intervals to capture a range of flow conditions. The water samples (filtered and unfiltered) were analyzed for field parameters (pH, temperature, specific conductance, and dissolved oxygen), nutrients (carbon, nitrogen, and phosphorous), optical properties (absorbance and fluorescence), 52 major and trace elements, 32 per- and polyfluoroalkyl substances (PFAS), and 113 pharmaceutical compounds. This data release provides a curated compilation of results from multiple USGS sources including: (1) Water Data for the Nation (USGS WDFN), (2) Organic Matter Research Laboratory (USGSOMRL), and (3) Analytical Trace Element Chemistry and Common Services Laboratory (USGSTECO). This dataset also lists Proxies Project codes that aligns these data with data in other data releases that include the same sites and sample times. The information compiled includes sample site location information, flow measurements, and all chemical measurements.