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Environmental Endocrine Disrupters: Effects and Possible Mechanism(s) in Young Male River Otters
Completed
The river otter (Lontra canadensis) is a top predator of most aquatic food chains. This mammal has adapted to a wide variety of aquatic habitats, from marine environments to high-mountain lakes of North America. River otter eat a wide variety of fish species and aquatic invertebrates, such as crabs, crayfish and mussels. This makes river otters good integrators of their aquatic environments and a useful species for determining both wildlife and human chemical exposure and potential harmful effects. A preliminary study involving the collection of a small number of otters from the lower Columbia River showed males less than one year old had significantly smaller baculum (penis bone) size and weight, and much smaller testes when compared to reference animals. The frozen otter carcasses were provided by trappers in both the Portland, Oregon metropolitan area and at various downstream sites along a 110 mile stretch of the lower Columbia River. No other body parameter appeared to be significantly different from those of reference animals. Reproductive organ hypoplasia of young male river otter was correlated with 6 organochlorine insecticides (OCs), 29 polychlorinated biphenyls (PCBs), 2 polychlorinated dibenzo-p-dioxins (PCDDs), and 4 polychlorinated dibenzofurans (PCDFs). The goal of this study is to further evaluate the relationship among the contaminants and observed reproductive organ hypoplasia in young male river otters, their occurrence, and mode of action or mechanism that causes hypoplasia with a larger series of data from throughout western Oregon and Washington.
PROGRAM: Contaminants Biology 5-YEAR GOAL: (goal 2; objective 2A; strategies 2A-1, 2A-3)
Evaluate the ecological risk posed by contaminants. Objectives of the research are: (1) to further evaluate contaminants identified in the initial field study to determine those with the strongest possibility of the hypothesized hormone disruption. River otter from several river basins with differing contaminant body burden profiles will be used to compare physiological and biochemical measures of reproductive organs in a statistical model, (2) to quantify blood serum/plasma and gonadal tissue concentrations of selected sex hormones of male river otters from contaminated sites along the lower Columbia river and compare them to reference animals for possible endocrine alterations which may explain observed reproductive organ hypoplasia in young male river otters, (3) to quantify androgen and estrogen receptor numbers in select sex organ target tissue in relation to contaminant body burdens and examine receptor binding affinities of suspected xenobiotic androgens/antiandrogens and/or estrogen/antiestrogens which may be responsible for the observed reproductive organ hypoplasia in young male river otters, and (4) to develop a non-invasive biomonitoring method using river otter scats which would accurately reflect lipophilic contaminant body burdens and hormone levels of otters in contaminated situations.
Frozen otter carcasses will be obtained from trappers and some animals will be live-trapped to permit a more detailed evaluation. A detailed necropsy will be performed on each animal. Livers will be analyzed for OC pesticides, PCB congeners (42), PCDDs, PCDFs, a metal scan, perfluoroctane sulfonates, and butyltin compounds. Histology slides will be evaluated for general histology with gonadal tissue evaluated for spermatogenesis. In addition, testes will be evaluated for steroid hormones. Scat samples will be collected and analyzed for a series of chemicals to test their usefulness as a biomarker for regional contaminant patterns. Otters will be aged by the number of cementum layers in a canine tooth.
Grove, R.A., Henny, C.J., 2008, Environmental contaminants in male river otters from Oregon and Washington, USA, 1994-1999: Environmental Monitoring and Assessment, v. 145, p. 49-73. [Highlight] [Abs] [FullText] Catalog No: 1776 Grove, R.A., 2006, Environmental Contaminants in Male River Otters Collected from Oregon and Washington, 1994-1999, with Reproductive Organ Hypoplasia Observed in Otter Males: Corvallis, OR, Oregon State University--PhD Dissertation, 335 p. [FullText] Catalog No: 1718 Grove, R.A., Henny, C.J., 2005, Environmental Contaminants in River Otter ( Lontra canadensis) Collected from the Willamette River, 1996-99. Final Report to the U.S. Fish and Wildlife Service: U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, p. 98. [FullText] Catalog No: 1641 Grove, R.A., Bildfell, R., Henny, C.J., Buhler, D.R., 2003, Bilateral uric acid nephrolithiasis and ureteral hypertrophy in a free-ranging river otter ( Lontra canadensis): Journal of Wildlife Diseases, v. 39, no. 4, p. 914-917. [Highlight] [FullText] Catalog No: 1226 Grove, R.A., Buhler, D.R., Henny, C.J., Haffner, D., 2002, Organochlorine and heavy metal contaminants in river otter collected from the Puget Sound, 1996[abs.]: Proceedings of the 2001 Puget Sound Research Conference, p. 15. [FullText] Catalog No: 1945 Elliott, J.E., Henny, C.J., Harris, M.L., Wilson, L.K., Norstrom, R.J., 1999, Chlorinated hydrocarbons in livers of American mink ( Mustela vison) and river otter ( Lutra canadensis) from the Columbia and Fraser River Basins, 1990-1992: Environmental Monitoring and Assessment, v. 57, no. 3, p. 229-252. [Abs] [FullText] Catalog No: 611 Kannan, K., Grove, R.A., Senthilkumar, K., Henny, C.J., Geisy, J.P., 1999, Butyltin compounds in River Otters ( Lutra canadensis) from the Northwestern United States: Archives of Environmental Contamination and Toxicology, v. 36, no. 4, p. 462-468. [Abs] [FullText] Catalog No: 614 Henny, C.J., 1998, Environmental contaminants in waterbirds from the Great Basin (Abstract)[abs.]: Wetland Connectivity and Waterbird Conservation in the Western Great Basin of the United States Symposium, March, 1998. Workshop Abstracts., v. 85, p. 20. [FullText] Catalog No: 156 Hoberg, E.P., Henny, C.J., Hedstrom, O.R., Grove, R.A., 1997, Intestinal helminths of river otters ( Lutra canadensis) from the Pacific Northwest: Journal of Parasitology, v. 83, no. 1, p. 105-110. [FullText] Catalog No: 440
Henny, Charles J. - Research Zoologist
Phone: 541-757-4840
Email: charles_j_henny@usgs.gov
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