Students in the "Environmental Science" course at the Dakota County Community College in Rosemount, Minnesota, have been treated to a variety of guest speakers from the U. S. Fish and Wildlife Service.  On November 18, Annette Trowbridge, an Environmental Contaminants Biologist from the Twin Cities Ecological Services Field Office, provided an overview of how contaminants in the environment can adversely affect natural resources and provided examples illustrating how the principles of environmental health and ecotoxicology are applied to natural resource management in Minnesota .