title: Mercury and cadmium in ringed seals in the Canadian Arctic: Influence of location and diet.
abstract: Concentrations of total mercury (THg) and total cadmium (TCd) were determined in muscle and liver of ringed seals (Pusa hispida) from up to 14 locations across the Canadian Arctic. Location, trophic position (TP) and relative carbon source best predicted the THg and TCd concentrations in ringed seals. THg concentrations in ringed seals were highest in the western Canadian Arctic (Beaufort Sea), whereas TCd was highest in the eastern Canadian Arctic (Hudson Bay and Labrador). A positive relationship between THg and TP and a negative relationship between THg and relative carbon source contributed to the geographical patterns observed and elevated THg levels at certain sites. In contrast, a negative relationship between TCd and TP was found, indicating that high TCd concentrations are related to seals feeding more on invertebrates than fish. Feeding ecology appears to play an important role in THg and TCd levels in ringed seals, with biomagnification driving elevated THg levels and a dependence on low-trophic position prey resulting in high TCd concentrations. The present study shows that both natural geological differences and diet variability among regions explain the spatial patterns for THg and TCd concentrations in ringed seals.
authors.affiliation: Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada. Electronic address: tanya.brown@mun.ca.
authors.forename: Tanya M
authors.initials: TM
authors.lastname: Brown
authors.affiliation: Great Lakes Institute of Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada.
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Fisk
authors.affiliation: Environment Canada, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada.
authors.forename: Xiaowa
authors.initials: X
authors.lastname: Wang
authors.affiliation: Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Ferguson
authors.affiliation: University of Manitoba, 500 University Crescent, Winnipeg, Manitoba R3T 2N2, Canada.
authors.forename: Brent G
authors.initials: BG
authors.lastname: Young
authors.affiliation: Environmental Sciences Group, Royal Military College of Canada, PO Box 17000, Stn Forces, Kingston, Ontario K7K 7B4, Canada.
authors.forename: Ken J
authors.initials: KJ
authors.lastname: Reimer
authors.affiliation: Environment Canada, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada.
authors.forename: Derek C G
authors.initials: DC
authors.lastname: Muir
mesh_terms: D000818:Animals; D001110:Arctic Regions; D002104:Cadmium / Q000378:metabolism*; D004032:Diet; D004784:Environmental Monitoring; D008628:Mercury / Q000378:metabolism*; D046048:Seals, Earless / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D008628:Mercury
keywords: Cadmium; Mercury; Pusa hispida; Ringed seals; Spatial trends; Stable isotope analysis