title: Evaluation of anionic surfactant concentrations in US effluents and probabilistic determination of their combined ecological risk in mixing zones.
abstract: Alcohol sulfates (AS), alcohol ethoxysulfates (AES), linear alkyl benzenesulfonates (LAS) and methyl ester sulfonates (MES) are anionic surfactants that are widely used in household detergents and consumer products resulting in over 1 million tons being disposed of down the drain annually in the US. A monitoring campaign was conducted which collected grab effluent samples from 44 wastewater treatment plants (WWTPs) across the US to generate statistical distributions of effluent concentrations for anionic surfactants. The mean concentrations for AS, AES, LAS and MES were 5.03±4.5, 1.95±0.7, 15.3±19, and 0.35±0.13μg/L respectively. Since each of these surfactants consist of multiple homologues that differ in their toxicity, the concentration of each homologue measured in an effluent sample was converted into a toxic unit (TU) by normalizing to the predicted no effect concentration (PNEC) derived from high tier effects data (mesocosm studies). The statistical distributions of the combined TUs in the effluents were used in combination with distributions of dilution factors for WWTP mixing zones to conduct a US-wide probabilistic risk assessment for the aquatic environment for each of the surfactants. The 90th percentile level of TUs for AS, AES, LAS and MES in mixing zones were 1.89×10-2, 2.73×10-3, 2.72×10-2, and 3.65×10-5under 7Q10 (lowest river flow occurring over a 7day period every 10years) low flow conditions. Because these surfactants have the same toxicological mode of action, the TUs were summed and the aquatic safety for anionic surfactants as a whole was assessed. At the 90th percentile level under the conservative 7Q10 low flow conditions the forecasted TUs were 4.21×10-2which indicates that there is a significant margin of safety for the class of anionic surfactants in US aquatic environments.
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States. Electronic address: mcdonough.k@pg.com.
authors.forename: Kathleen
authors.initials: K
authors.lastname: McDonough
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Casteel
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Nina
authors.initials: N
authors.lastname: Itrich
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Menzies
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Scott
authors.initials: S
authors.lastname: Belanger
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wehmeyer
authors.affiliation: The Procter and Gamble Company, Mason Business Center, Mason, OH 45040, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Federle
mesh_terms: D000476:Alkanesulfonates / Q000032:analysis*; D004784:Environmental Monitoring; D006801:Humans; D018570:Risk Assessment; D013431:Sulfates / Q000032:analysis*; D013501:Surface-Active Agents / Q000032:analysis*; D014481:United States; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000476:Alkanesulfonates; D013431:Sulfates; D013501:Surface-Active Agents; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Aquatic; Dilution factors; Risk assessment; Toxic units; WWTP monitoring