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203 Contaminants in Great Lakes Fish: Historic, Current, and Emerging Concerns Cheryl A. Murphy, Satyendra P. Bhavsar, and Nilima Gandhi The Great Lakes basin has seen some dramatic changes over the past century. The area has experienced marked changes in land use, accelerated population and industrial growth, and a vast array of contaminants and anthropogenic stressors that have changed in composition and relative importance over time. There have been several international treaties and policy initiatives put forth to deal with contaminants and stressors, but contaminants of concern continue to change as our technology changes. In past, we focused on harmful effects of industrial wastes, and several policy initiatives were formulated to ameliorate these effects. Although we are still dealing with the legacy of industrial wastes, attention now focuses on emerging stressors, such as recently-detected persistent organic pollutants, pharmaceuticals, low dissolved oxygen, nanotechnology, and invasive species. To put this problem into perspective, the Environmental Protection Agency (EPA) has registered more than eighty-three thousand substances on the Toxic Substances Control Act (TSCA) Inventory, which includes chemicals manufactured or processed in the United States (see additional information for website: Toxic Substances Control Act Inventory); most have not been appropriately tested for toxicity (Denison 2007). In addition to single contaminants, there is now growing concern regarding the effects of multiple stressors—a more realistic scenario for the Great Lakes. It is hypothesized that multiple stressors can act additively, synergistically, or antagonistically, but, unfortunately, even just the effect of a single stressor is often unknown. This chapter begins with a brief overview of the major events related to contaminant release and contaminant control in the Great Lakes basin over the last one hundred years. It then discusses contaminant biomonitoring programs in the Great Lakes basin and the availability of various types of data. Next, it reviews contaminants in light of their physical-chemical properties, as well as toxicologically relevant and observed levels in Great Lakes fish and, where required, other matrices (e.g., sediments) on temporal and spatial scales, and related industrial and government actions. Finally, this chapter reflects on important lessons and evaluates the future outlook and necessary management actions based on more than half a century in handling pollution problems in Great Lakes fish. Murphy, Bhavsar, and Gandhi 204 Contaminants in the Great Lakes: Brief History The first major anthropogenic stressor to the Great Lakes basin that likely changed water chemistry and aquatic life dramatically was the extensive and widespread logging that occurred around the mid-1800s by early Euro-American settlers. These early logging practices permanently altered the landscape and switched the dominant vegetation from mixed conifer-broadleaf forests to open land vegetation consisting primarily of row crop agriculture and grassland (Vogelmann et al. 2001; Schulte et al. 2007). Accompanying this switch was a loss in plant diversity and structural complexity, resulting in a vegetation homogenization over the entire northern U.S. Great Lakes region (Schulte et al. 2007). Such dramatic changes to vegetation can have cascading effects through ecosystems and impact water flow, nutrient cycles, vegetation and soil composition/structure, and terrestrial and aquatic species diversity (Foley et al. 2005). The United States and Canada started a long history of working together to address significant issues related to shared waters, by signing the Boundary Waters Treaty in 1909. In the 1940s, demands for chemicals, rubber, steel, weapons, and other materials in support of World War II led to a major industrial expansion in the Great Lakes basin. This period marked the beginning of large-scale discharges of various man-made chemicals to the Great Lakes (Ihde 1978). During the 1950s, an excessive input of phosphorus from sewage and detergents into the Great Lakes caused excessive growth of algae in Lake Erie (Beeton 1963). The decomposition of dead algae consumed oxygen from water, which affected a large part of the aquatic food web. Lake Erie had extensive areas of low dissolved oxygen, also known as “dead zones,” and was itself regarded as “dying.” As the economy of the Great Lakes region grew, so did the industrial wastes. The use of polychlorinated biphenys (PCBs) mainly as fire resistant hydraulic and electrical fluids and of dichlorodiphenyltrichloroethane (DDT) widely used as an agricultural insecticide grew between 1940 and 1960. Both PCBs and DDT are persistent (i.e., have fairly long half-lives), are lipophilic, and have been shown to bioaccumulate. Other persistent organochlorine pesticides (e.g., mirex, lindane, aldrin, endrin, chlordane, and heptachlor epoxide) were also used extensively during the 1960s and accumulated...

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