Household and personal care products (like shampoo, hand soap, and laundry detergent) are used daily, and in high volumes. Often times, the end life of the chemicals in these products are disposed of "down-the-drain". iSTREEM® is a free, web-based GIS-model that estimates the concentration of "down-the-drain" chemicals within the aquatic environment. It was created in order to promote product stewardship and regulatory compliance among chemical suppliers and formulated product manufactures. 

iSTREEM full color CMYK TM

WHAT’S NEW in version 2.0?

Most recent wastewater facility information from EPA added, increasing total number of facilities in model by 27%.

  • Facility information updated using 2012 Clean Watershed Needs Survey.
  • Conversion of underlying river network to higher spatial resolution, National Hydrology Dataset Plus (NHDPlus).
  • iSTREEM output can be directly linked to NHDPlus and USEPA StreamCat.
  • Users can now download model results to be used in QGIS, Esri ArcReader, and Esri ArcMap.
  • Algorithm enchantments and improved processing performance.Society for Environmental Toxiocology and Chemistry (SETAC) course:  iSTREEM® – A Web-based River Chemical Concentration Estimation Model

iSTREEM® 2.0 estimates the concentration of these chemicals at the discharge of over 13,000 wastewater treatment plants (WWTPs), and at the intake of 1,700 downstream municipal drinking water treatment facilities. The model measures approximately 228,00 river segments, covering over 243,000 river miles.

Version River Network WWTP DWI
1.4 25,200 segments
209,000 river miles
Total Pop = 138 million
Total Flow = 21,200 MGD
2.0 228,000 segments
243,000 river miles
Total Pop = 185 million
Total Flow = 25,500
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  • Simonich S., Sun P, Casteel K, Dyer S, Wernery D, Garber K, Carr G, and Federle T. Probabilistic Analysis of Risks to US Drinking Water Intakes from 1,4-Dioxane in Domestic Wastewater Treatment Plant Effluents. Integrated Environmental Assessment and Management (2013) 9(4): 554–559. (
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  • Kapo KE, DeLeo P, Vamshi R, Holmes CM, Ferrer D, Dyer SD, Wang X, White-Hull C. 2016. iSTREEM®: an approach for broad-scale in-stream exposure assessment of "down-the-drain" chemicals. Integrated Environmental Assessment and Management. 2016. 12(4): 782-792
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