Concentrations of Inorganic and Organic Substances in Lake Ontario and Surrounding Tributaries, New York, April to October 2023

This data release contains nutrient, metal, hormone, pharmaceutical, dioxin, and furan concentration data and field readings associated with surface water samples collected from 35 locations along the New York shoreline of Lake Ontario and surrounding tributaries. Samples were collected from April 2023 through October 2023 at nearshore, embayment, and tributary sites 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 water's surface. Tributaries were sampled at several points in across the channel cross section based on the equal-discharge-increments (EDI) method to create one composite sample. Samples were analyzed for 174 target substances (nutrient, metal, hormone, pharmaceutical, dioxin, furan, suspended solids, nonylphenols, mirex), 75 quality assurance samples (isotopes and surrogates), and 8 calculated substances based on sample results. 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.