Statewide Endocrine Disrupting Compound Monitoring Study 2007 - 2008

It is well established that some chemicals can mimic the effects of hormones in animals and cause adverse physiologic effects such as changes to the reproductive system or to the growth and development of an organism. These endocrine disrupting compounds, or EDCs, do not usually exhibit acute toxicity at the levels normally found in the environment, but instead can alter the normal functioning and growth of the exposed organism at very low concentrations. Previous investigations of the Mississippi River and its tributaries have shown that EDCs are widespread at low concentrations in rivers. The studies also demonstrated that fish in these waters show signs of endocrine disruption, such as the feminization of male fish. Most of these investigations focused on locations near wastewater treatment plants (WWTPs). Much less is known, however, about the presence of EDCs and their effects in Minnesota's lakes. In this study, commissioned by Minnesota lawmakers in the 2007 Legislative Session, twelve lakes and four rivers in Minnesota were sampled for the presence and concentrations of a diverse group of EDCs and other chemicals in surface water and sediment. In addition, caged and wild-caught fish from these bodies of water were examined for evidence of endocrine disruption and environmental stress. The lakes and rivers were selected to represent a wide range of land use and development. Two lakes without development were selected as reference lakes. Three rivers in south-central Minnesota and one in western Minnesota were also included in the study.