Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature

Limnology and Oceanography
By: , and 

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Abstract

We conducted a study with cadmium (Cd) and copper (Cu) in the delta of San Francisco Bay, using nitrogen and carbon stable isotopes to identify trophic position and food web structure. Cadmium is progressively enriched among trophic levels in discrete epiphyte‐based food webs composed of macrophyte‐dwelling invertebrates (the first link being epiphytic algae) and fishes (the first link being gobies). Cadmium concentrations were biomagnified 15 times within the scope of two trophic links in both food webs. Trophic enrichment in invertebrates was twice that of fishes. No tendency toward trophic‐level enrichment was observed for Cu, regardless of whether organisms were sorted by food web or treated on a taxonomic basis within discrete food webs. The greatest toxic effects of Cd are likely to occur with increasing trophic positions, where animals are ingesting Cd‐rich prey (or food). In Franks Tract this occurs within discrete food chains composed of macrophyte‐dwelling invertebrates or fishes inhabiting submerged aquatic vegetation. Unraveling ecosystem complexity is necessary before species most exposed and at risk can be identified.

Publication type Article
Publication Subtype Journal Article
Title Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature
Series title Limnology and Oceanography
DOI 10.4319/lo.2005.50.5.1511
Volume 50
Issue 5
Year Published 2005
Language English
Publisher Wiley
Contributing office(s) San Francisco Bay-Delta, Toxic Substances Hydrology Program, Pacific Regional Director's Office
Description 9 p.
First page 1511
Last page 1519
Online Only (Y/N) N
Additional Online Files (Y/N) N
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