Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: health implications in an urbanized estuary.
We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n=138) and blood (n=73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted.
Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA. Electronic address: emchuron@ucsc.edu.
Elizabeth A
EA
McHuron
Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA.
James T
JT
Harvey
Institute of Marine Science, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, P.O. Box 757220, Fairbanks, AK 99775-7220, USA.
J Margaret
JM
Castellini
U.S. Geological Survey, Fort Collins Science Center, Denver Federal Center, Building 21, MS963, Denver, CO 80225, USA.
Craig A
CA
Stricker
Department of Veterinary Medicine, University of Alaska Fairbanks, P.O. Box 755940, Fairbanks, AK 99775-7000, USA.
Todd M
TM
O'Hara
D000818:Animals; D002140:California; D063366:Estuaries; D005260:Female; D006197:Hair / Q000737:chemistry; D008297:Male; D008628:Mercury / Q000097:blood*; D046049:Phoca / Q000097:blood*; D012643:Selenium / Q000097:blood*; D014507:Urbanization; D014874:Water Pollutants, Chemical / Q000097:blood*
D014874:Water Pollutants, Chemical; D008628:Mercury; D012643:Selenium
Blood; Hair; Marine mammals; San Francisco Bay; Stable isotopes (C, N, S); Trace elements