Concentration results for per- and polyfluoroalkyl substances (PFAS) analyzed in fish tissue, bed sediment, and biofilm samples, Montana, 2023

This data release contains the concentration results of per- and polyfluoroalkyl substances (PFAS) collected in fish tissue and whole blood, bed sediment and biofilm samples from water bodies in and surrounding the Little Bighorn River (LBHR) in Montana in July 2023. A total of 29 filets and whole blood samples were collected from 10 brown trout, 10 catfish, 6 rock bass, and 3 goldeye specimens collected by U.S. Geological Survey personnel and community volunteers in two locations along the LBHR. Bed sediment samples were collected from the top 2.54 centimeters in depositional zones in 12 sampling locations where surface-water-quality samples also were collected (Romanok and others, 2023). Biofilm scrapings were collected from rocks at five locations on the LBHR where bed-sediment and surface-water-quality samples were collected. Fish filet, whole blood, and biofilm samples were analyzed for 28 PFAS at RTI Laboratories, Inc., Livonia, Michigan, following EPA method 537.1 (liquid chromatography, tandem mass spectrometry). Bed-sediment samples were analyzed for 40 PFAS at SGS AXYS, Sidney, British Columbia, Canada, also using EPA method 537.1. References cited: Romanok, K.M., Bradley, P.M., Smalling, K.L., Doyle, J.T., Eggers, M.J., Gray, J.L., Hladik, M.L., Kanagy, L.K., McCleskey, R.B., Meppelink, S.M., Richards, C.L., and Roth, D.A., 2023, Target-chemical concentrations and microbiological results in surface water and tapwater, Montana, 2022-23 (ver. 2.0, December 2025): U.S. Geological Survey data release, https://doi.org/10.5066/P9R7MV6I.