Endocrine disrupting chemicals in the Chesapeake Bay watershed: Evidence for effects on fish populations

Land-use practices in the Chesapeake Bay watershed are diverse and include urban/residential activities, industrialized areas, row-crop agriculture, and high-density animal production facilities. Fish die-offs and the elevated occurrence of intersex condition among bass populations within tributaries to the Chesapeake Bay raised questions regarding linkages of these adverse outcomes and land-use in the region. In particular, resource managers were concerned that endocrine disrupting chemicals (EDCs) may be responsible for testicular oocytes (intersex) in male bass and elevated rates of disease in fish populations. Congress requested the Environmental Health Mission Area of U.S. Geological Survey develop a set of studies to evaluate the sources and occurrence of EDCs within the Chesapeake Bay watershed, as well as the potential effects on fish and wildlife populations. The seminar will provide an overview of this program with special emphasis on studies designed to evaluate the sensitivity of bass towards EDCs and an effects-directed analysis (EDA) aimed at identification of chemicals causally-linked to the observed adverse effects.