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Quality of a River - Water Quality
Contaminants: Endocrine disruptors (pg 7 of 8)



Endocrine disruptors in streams exert their most obvious effect on fish, since fish spend their lives in the stream environment. In Minnesota, for example, both carp and walleye collected from the effluent channel of the Metropolitan Wastewater Treatment Plant in St. Paul showed signs of gender-bending, with not only females but also males of each species producing vitellogenin, a protein needed for egg-making. Male walleye collected from control sites did not have vitellogenin (Folmar et al., 1996); (Lee et al., 2000); (Folmar et al., 2001).

In Lake Pepin, a large pool of the Mississippi downstream from the Twin Cities, U.S. Geological Survey scientists discovered male smallmouth bass with immature eggs in their testes. Fish taken from many streams have shown signs of endocrine disruption, including abnormal ovaries, testes, and sex hormone levels. The effect on fish populations is still unclear (Schmitt et al., 2002).

Sandra Steingraber
Hear Sandra Steingraber
Chemicals in the water

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