Sunlight-driven Transformation of Organic Contaminants

Stormwater runoff transports pesticides, pharmaceuticals, antibiotics, and other organic micro-contaminants from our cities and farmland to natural or engineered surface waters. Rarely is specific treatment done to remove these contaminants, and consequently we rely on natural processes that transport and transform these contaminants to maintain environmental concentrations below harmful levels. Photochemical reactions initiated by sunlight are important in the natural attenuation of these contaminants and may be important in limiting downstream ecological impacts and human exposure. Little is known, however, about the way in which watershed land cover and water chemistry control the photochemical fate of these contaminants. In this research project, we have studied the photochemistry of these contaminants in urban and rural runoff collected from the Minneapolis-St. Paul region. The outcomes of this research will provide design parameters for constructed wetlands and detention ponds that optimize conditions for photochemical transformation reactions of organic micro-contaminants in rural and urban landscapes.

Project Staff: 

William Arnold and Andrew J. McCabe