Biology - Contaminant Biology Program
Endocrine DisruptionThe ability of environmental contaminants to affect reproductive and developmental processes in fish and wildlife species has long been known. An increasingly persuasive body of evidence indicates that many of these chemicals may be causing such effects through interference and disruption of normal endocrine function. Field observations have correlated abnormal sex organ morphology, unusual sex hormone levels and ratios, and altered physiological and biochemical processes with exposure to environmental contaminants. These developmental end points are under the control of the endocrine system, lending support to the hypothesis that environmental contaminants may disrupt endocrine function.
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River otter baculi. USGS biologists in Corvallis, OR, studied river otters in the lower Columbia River and found a correlation between the size of the baculum, a bone found in the penises of certain mammal groups, and PCB concentrations.
Egg and sperm cells of fish. USGS biologists have found "intersex" fish (those with both eggs and sperm) in many aquatic environments throughout the country. August 2006 testing at three tributaries emptying into the Potomac revealed that more than 80 percent of all male smallmouth bass found were growing eggs, according to Vicki S. Blazer, a fish pathologist within the U.S. Geological Survey. Listen to USGS CoreCast "Endocrine Disruption: Sex-Changing Fish and More" to learn more about the effects humans are having on aquatic life by introducing chemicals and waste products into lakes and streams. Featured Publications
Lead authors Dr. David Alvarez, Columbia Environmental Research Center, Columbia, MO, and Dr. Luke Iwanowicz, National Fish Health Research Laboratory, Kearneysville, WV, and their co-authors, detail the reproductive health of the bass and the seasonal occurrence of persistent and emerging organic contaminants. Further sampling is also being conducted in the mainstream upper Potomac River and the tidal area downriver of Washington, D.C. Partners in these studies include the U.S. Fish and Wildlife Service and the Maryland Department of Natural Resources Fisheries Service. (David Alvarez, Columbia, MO 573-441-2970)
Iwanowicz, L.R., Blazer, V.S., Guy, C.P., Pinkney, A.E., Mullican, J.E. and Alvarez, D.A. 2009, Reproductive health of bass in the Potomac, USA, drainage: Part 1. Exploring the effects of proximity to wastewater treatment and plant discharge. Reproductive health of bass in the Potomac, USA, drainage: Part 1. Exploring the effects of proximity to wastewater treatment and plant discharge. Environmental Toxicology and Chemistry, 28(5): 1072-1083.
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