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Age and trophic position dominate bioaccumulation of mercury and organochlorines in the food web of Lake Washington

Science of the Total Environment

By:
and
DOI: 10.1016/j.scitotenv.2006.10.035

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Abstract

Understanding the mechanisms of bioaccumulation in food webs is critical to predicting which food webs are at risk for higher rates of bioaccumulation that endanger the health of upper-trophic predators, including humans. Mercury and organochlorines were measured concurrently with stable isotopes of nitrogen and carbon in key fishes and invertebrates of Lake Washington to explore important pathways of bioaccumulation in this food web. Across the food web, age and trophic position together were highly significant predictors of bioaccumulation. Trophic position was more important than age for predicting accumulation of mercury, ???DDT, and ???-chlordane, whereas age was more important than trophic position for predicting ???PCB. Excluding age from the analysis inflated the apparent importance of trophic position to bioaccumulation for all contaminants. Benthic and pelagic habitats had similar potential to bioaccumulate contaminants, although higher ???-chlordane concentrations in organisms were weakly associated with more benthic carbon signals. In individual fish species, contaminant concentrations increased with age, size, and trophic position (??15N), whereas relationships with carbon source (??13C) were not consistent. Lipid concentrations were correlated with contaminant concentrations in some but not all fishes, suggesting that lipids were not involved mechanistically in bioaccumulation. Contaminant concentrations in biota did not vary among littoral sites. Collectively, these results suggest that age may be an important determinant of bioaccumulation in many food webs and could help explain a significant amount of the variability in apparent biomagnification rates among food webs. As such, effort should be made when possible to collect information on organism age in addition to stable isotopes when assessing food webs for rates of biomagnification. ?? 2006 Elsevier B.V. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Age and trophic position dominate bioaccumulation of mercury and organochlorines in the food web of Lake Washington
Series title:
Science of the Total Environment
DOI:
10.1016/j.scitotenv.2006.10.035
Volume
372
Issue:
2-3
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Science of the Total Environment
First page:
571
Last page:
584
Number of Pages:
14