Concentrations of Per- and Polyfluoroalkyl Substances (PFAS) in Lake Ontario and Surrounding Tributaries, New York, July to September 2023

This data release contains per- and polyfluoroalkyl substances (PFAS) concentration data from surface water samples collected from 35 locations along the New York shoreline of Lake Ontario and surrounding tributaries. Samples were collected monthly from July 2023 through September 2023 at nearshore, embayments, and tributaries from Niagara River to Chaumont Bay. Nearshore and embayment locations were grab samples collected approximately 4 to 60 feet from the shoreline, depending on water level conditions, and no more than 0.5 feet below the waters surface. Tributaries were sampled at several points across the channel cross section based on the equal-discharge-increment (EDI) method to create one composite sample. Samples were analyzed for 40 PFAS compounds using EPA draft method 1633. Field replicate and field blank samples were collected for quality assurance and quality control purposes. Laboratory quality control samples included isotope dilution standard recoveries, method blanks, and matrix spike isotope dilution standard recoveries.