Mercury and cadmium in ringed seals in the Canadian Arctic: Influence of location and diet

Document Type

Article

Publication Date

3-1-2016

Publication Title

Science of the Total Environment

Volume

545-546

First Page

503

Keywords

Cadmium, Mercury, Pusa hispida, Ringed seals, Spatial trends, Stable isotope analysis

Last Page

511

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.

DOI

10.1016/j.scitotenv.2015.12.030

ISSN

00489697

E-ISSN

18791026

PubMed ID

26760271

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