Triclosan and Triclosan-derived Dioxins in the Mississippi River Sediment Record

Project Staff: 

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

Funding: 

USGS-WRRI 104B/ CAIWQ Competitive Grants Program

Project Duration: 

March 2007 - February 2008

Summary: 

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.

Publications: 

Books and Book Chapters

Arnold, W.A., K. McNeill. 2007. “Transformation of Pharmaceuticals in the Environment: Photolysis and Other Processes” In M. Petrovic and D. Barcelo (eds). An Analysis, Fate and Removal of Pharmaceuticals in the Water Cycle. Elsevier Science, Amsterdam, The Netherlands. Pages 361 – 383.

Conference Proceedings

Buth, J.M., W.A. Arnold, K. McNeill. 2009. Formation and Occurrence of Chlorinated Triclosan Derivatives (CTDs) and their Dioxin Photoproducts. Micropol & Ecohazard 2009. 6th IWA/GRA Specialized Conference on Assessment and Control of Micropollutants/Hazardous Substances in Water, June 8-10, 2009, San Francisco, CA.

Steen, P.O., Grandbois, M., McNeill, K., Arnold, W.A. 2009. Photolysis of Hydroxylated Polybrominated Diphenyl Ethers. Micropol & Ecohazard 2009. 6th IWA/GRA Specialized Conference on Assessment and Control of Micropollutants/Hazardous Substances in Water, June 8-10, 2009, San Francisco, CA.

Steen, P.O., Grandbois, M., Arnold, W.A., McNeill, K. 2008. Hydroxylated Polybrominated Diphenyl Ether Photolysis: Quantum Yields and Product Identification. Oral Presentation. Minnesota Water Conference, October 27-28, 2008, St. Paul, MN.

Steen, P.O., M. Grandbois, W.A. Arnold, K. McNeill. 2008. Hydroxylated polybrominated diphenyl ether photolysis quantum yields and product identification. Oral Presentation Environmental Chemistry Division, ACS National Meeting, August 17-21, 2008, Philadelphia, PA, 48(2), 608-611.

Buth, J.M., Arnold, W.A., McNeill, K. 2008. Photochemical Fate of Chlorinated Triclosan Derivatives. Poster Presentation. Gordon Research Conference, Environmental Sciences: Water, June 22 – 28, 2008, Holderness, NH.

Other Publications

McNeill, K., 2009. Incineration or liquid handsoap: Which is the larger source of dioxins to the aquatic environment? College of St. Catherine, St. Paul, MN.

McNeill, K., 2009. Incineration or liquid handsoap: Which is the larger source of dioxins to the aquatic environment? Gustavus Adolphus College, St. Peter, MN.

Arnold, W.A., 2008. Pharmaceutical Photolysis and Impacts: Tetracycline and Triclosan. ETH-Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, Switzerland.

Arnold, W.A., 2007. Solar photochemistry of pharmaceutical compounds. American Water Works Association Water Quality Technology Conference, Advanced Oxidation Technologies in Water Treatment: Fundamentals and Applications Workshop, November 4, 2007.