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Triclosan and triclosan-derived dioxins in the Mississippi River sediment record

PIs: Kristopher McNeill, Associate Professor and William Arnold, Associate Professor, Department of Civil Engineering, University of Minnesota

Funding Source: USGS-WRRI 104B/ CAIWQ Competitive Grants Program

Project Duration: 3/1/07 - 2/29/08

This project is focused on establishing whether triclosan has been and continues to be a source of dioxins to the aquatic environment. It is hypothesized that triclosan, a widely used antimicrobial found in consumer products, is transformed into toxic dioxin compounds through chlorination of triclosan-containing wastewater and sunlight exposure in rivers that receive chlorinated wastewater. It is further hypothesized that triclosan and its products will associate with the sediment downstream of point of discharge and their release to the environment thus will be recorded in the sediment record. To determine the historical inputs of triclosan and its products in to the Upper Mississippi river from Minnesota’s largest wastewater treatment plant, the Metro Plant, in St. Paul, sediment cores from Lake Pepin will be analyzed. It is expected that triclosan and its products will not be found in pre-1960 sediment, it will be at low levels between 1960 and 1990 when its use was limited, and will be at the highest levels after 1990 following its widespread use in liquid handsoap and toothpaste. The results of this study will further our understanding of micropollutants in wastewater and will provide specific information about the appropriateness of chlorination disinfection for triclosan-containing waters.