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dc.contributor.authorWalters, David M.
dc.contributor.authorRosi-Marshall, Emma
dc.contributor.authorKennedy, Theodore A.
dc.contributor.authorCross, Wyatt F.
dc.contributor.authorBaxter, Colden V.
dc.date.accessioned2016-02-25T23:12:56Z
dc.date.available2016-02-25T23:12:56Z
dc.date.issued2015-10
dc.identifier.citationWalters, David M., Emma Rosi-Marshall, Theodore A. Kennedy, Wyatt F. Cross, and Colden V. Baxter. "Mercury & selenium accumulation in the Colorado River food web, Grand Canyon, USA." Environmental Toxicology & Chemistry 34, no. 10 (October 2015): 2385-2394. DOI: 10.1002/etc.3077.en_US
dc.identifier.issn0730-7268
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/9601
dc.description.abstractMercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long‐range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries.en_US
dc.description.sponsorshipUS Geological Survey Grand Canyon Monitoring & Research Center; the US Environmental Protection Agency Office of Research & Developmenten_US
dc.titleMercury and selenium accumulation in the Colorado River food web, Grand Canyon, USAen_US
dc.typeArticleen_US
mus.citation.extentfirstpage2385en_US
mus.citation.extentlastpage2394en_US
mus.citation.issue10en_US
mus.citation.journaltitleEnvironmental Toxicology & Chemistryen_US
mus.citation.volume34en_US
mus.identifier.categoryLife Sciences & Earth Sciencesen_US
mus.identifier.doi10.1002/etc.3077en_US
mus.relation.collegeCollege of Letters & Scienceen_US
mus.relation.departmentEcology.en_US
mus.relation.universityMontana State University - Bozemanen_US
mus.data.thumbpage3en_US


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