iSTREEM is a web-based computer model that predicts concentrations of a chemical used in consumer products with down-the-drain disposal in approximately 22,000 river segments across 200,000 river miles in the continental United States receiving municipal wastewater discharges. This model differs from other surface water models by incorporating widely dispersed discharges across broad geographies, incorporating loads of consumer product ingredients from more than 10,000 municipal wastewater treatment plants. The model also provides the ability to predict the concentration distributions of a chemical at the intake of a municipal (drinking) water treatment facility as a result of upstream wastewater treatment plant discharges.

The model provides information on:

• The distribution of consumer product ingredient concentrations in river waters, including drinking water intakes, by the percent of river miles or the population served
• The number or percentage of river miles for which concentrations of the consumer product ingredient exceed a certain value
• The number of facilities that could receive raw drinking water containing a consumer product ingredient above a certain concentration
• The locations of WWTPs and drinking water facilities for reaches with high ingredient concentrations

In addition, U.S. EPA databases included in the iSTREEM system provide information on wastewater treatment plants and drinking water facility characteristics and locations, and river characteristics. This information can be used to design monitoring studies and to address specific regional issues.

For more information and to begin using iSTREEM, go to the ACI Science website (http://www.aciscience.org) and navigate to “Environmental Health” and “iSTREEM” using the navigation bar on the left.