title: iSTREEM(®) : An approach for broad-scale in-stream exposure assessment of "down-the-drain" chemicals.
abstract: The "in-stream exposure model" iSTREEM(®) , a Web-based model made freely available to the public by the American Cleaning Institute, provides a means to estimate concentrations of "down-the-drain" chemicals in effluent, receiving waters, and drinking water intakes across national and regional scales under mean annual and low-flow conditions. We provide an overview of the evolution and utility of the iSTREEM model as a screening-level risk assessment tool relevant for down-the-drain products. The spatial nature of the model, integrating point locations of facilities along a hydrologic network, provides a powerful framework to assess environmental exposure and risk in a spatial context. A case study compared national distributions of modeled concentrations of the fragrance 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8,-hexamethylcyclopenta-γ-2-benzopyran (HHCB) and the insect repellent N,N-Diethyl-m-toluamide (DEET) to available monitoring data at comparable flow conditions. The iSTREEM low-flow model results yielded a conservative distribution of values, whereas the mean-flow model results more closely resembled the concentration distribution of monitoring data. We demonstrate how model results can be used to construct a conservative estimation of the distribution of chemical concentrations for effluents and streams leading to the derivation of a predicted environmental concentration (PEC) using the high end of the concentration distribution (e.g., 90th percentile). Data requirements, assumptions, and applications of iSTREEM are discussed in the context of other down-the-drain modeling approaches to enhance understanding of comparative advantages and uncertainties for prospective users interested in exposure modeling for ecological risk assessment. Integr Environ Assess Manag 2016;12:782-792. © 2016 SETAC.
authors.affiliation: Waterborne Environmental, Leesburg, Virginia, USA. kapok@waterborne-env.com.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Kapo
authors.affiliation: American Cleaning Institute, Washington DC, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: DeLeo
authors.affiliation: Waterborne Environmental, Leesburg, Virginia, USA.
authors.forename: Raghu
authors.initials: R
authors.lastname: Vamshi
authors.affiliation: Waterborne Environmental, Leesburg, Virginia, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Holmes
authors.affiliation: American Cleaning Institute, Washington DC, USA.
authors.forename: Darci
authors.initials: D
authors.lastname: Ferrer
authors.affiliation: The Procter & Gamble Company, Cincinnati, Ohio, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Dyer
authors.affiliation: University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Xinhao
authors.initials: X
authors.lastname: Wang
authors.affiliation: The Procter & Gamble Company, Cincinnati, Ohio, USA.|Retired.
authors.forename: Charlotte
authors.initials: C
authors.lastname: White-Hull
mesh_terms: D003671:DEET; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D008956:Models, Chemical; D011446:Prospective Studies; D018570:Risk Assessment; D045483:Rivers; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D014874:Water Pollutants, Chemical; D003671:DEET
keywords: Effluent; Exposure model; Geographic information systems; Risk assessment; Wastewater