Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada.
Great Lakes Institute of Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada.
Sci Total Environ. 2016 Mar 1;545-546:503-11. doi: 10.1016/j.scitotenv.2015.12.030. Epub 2016 Jan 4.
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.
在加拿大北极的多达 14 个地点，测定了环斑海豹（Pusa hispida）肌肉和肝脏中的总汞（THg）和总镉（TCd）浓度。位置、营养位置（TP）和相对碳源最佳预测了环斑海豹中的 THg 和 TCd 浓度。在加拿大西部北极（波弗特海），环斑海豹的 THg 浓度最高，而在加拿大东部北极（哈德逊湾和拉布拉多），TCd 浓度最高。THg 与 TP 之间的正相关关系以及 THg 与相对碳源之间的负相关关系导致了所观察到的地理模式和某些地点 THg 水平升高。相比之下，发现 TCd 与 TP 之间呈负相关关系，表明高 TCd 浓度与海豹更多地以无脊椎动物而不是鱼类为食有关。摄食生态似乎在环斑海豹的 THg 和 TCd 水平中起着重要作用，生物放大作用导致 THg 水平升高，对低营养位置猎物的依赖导致 TCd 浓度升高。本研究表明，自然地质差异和区域间饮食的变化都解释了环斑海豹中 THg 和 TCd 浓度的空间模式。
