title: Probabilistic analysis of risks to US drinking water intakes from 1,4-dioxane in domestic wastewater treatment plant effluents.
abstract: The risks of 1,4-dioxane (dioxane) concentrations in wastewater treatment plant (WWTP) effluents, receiving primarily domestic wastewater, to downstream drinking water intakes was estimated using distributions of measured dioxane concentrations in effluents from 40 WWTPs and surface water dilution factors of 1323 drinking water intakes across the United States. Effluent samples were spiked with a d8 -1,4-dioxane internal standard in the field immediately after sample collection. Dioxane was extracted with ENVI-CARB-Plus solid phase columns and analyzed by GC/MS/MS, with a limit of quantification of 0.30 μg/L. Measured dioxane concentrations in domestic wastewater effluents ranged from <0.30 to 3.30 μg/L, with a mean concentration of 1.11 ± 0.60 μg/L. Dilution of upstream inputs of effluent were estimated for US drinking water intakes using the iSTREEM model at mean flow conditions, assuming no in-stream loss of dioxane. Dilution factors ranged from 2.6 to 48 113, with a mean of 875. The distributions of dilution factors and dioxane concentration in effluent were then combined using Monte Carlo analysis to estimate dioxane concentrations at drinking water intakes. This analysis showed the probability was negligible (p = 0.0031) that dioxane inputs from upstream WWTPs could result in intake concentrations exceeding the USEPA drinking water advisory concentration of 0.35 μg/L, before any treatment of the water for drinking use.
authors.affiliation: Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon, USA; Department of Chemistry, Oregon State University, Corvallis, Oregon, USA.
authors.forename: Staci Massey
authors.initials: SM
authors.lastname: Simonich
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: Ken
authors.initials: K
authors.lastname: Casteel
authors.forename: Scott
authors.initials: S
authors.lastname: Dyer
authors.forename: Dave
authors.initials: D
authors.lastname: Wernery
authors.forename: Kevin
authors.initials: K
authors.lastname: Garber
authors.forename: Gregory
authors.initials: G
authors.lastname: Carr
authors.forename: Thomas
authors.initials: T
authors.lastname: Federle
mesh_terms: D004146:Dioxanes / Q000032:analysis*; D060766:Drinking Water / Q000737:chemistry*; D011336:Probability; D018570:Risk Assessment; D014481:United States; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004146:Dioxanes; D060766:Drinking Water; D062065:Wastewater; D014874:Water Pollutants, Chemical; C025223:1,4-dioxane
keywords: 1,4-Dioxane; Drinking water intake; Effluent; Probabilistic analysis; WWTP