Rohonczy et al. 2024 — Cadmium and mercury trophic transfer in the Arctic marine food web, Hudson Bay
This study quantified cadmium and mercury (total and methylmercury) concentrations across multiple trophic levels in the Hudson Bay Arctic marine food web, including blue mussel (Mytilus edulis), common eider (Somateria mollissima), shorthorn sculpin (Myoxocephalus scorpius), Arctic cod (Boreogadus saida), and ringed seal (Pusa hispida). The authors examined trophic magnification factors (TMF) for both metals and compared Hudson Bay concentrations against available regulatory limits and prior circumpolar baseline data. The paper documents how climate change and reduced sea ice in Hudson Bay may be altering metal cycling and trophic transfer in Arctic marine ecosystems.
Key numbers
Total sample size: n=781 across species and matrices (THg n=436, Cd n=345 reported). THg biomagnifies strongly through the food web (TMF >1 for methylmercury). Cd does not biomagnify (TMF <1 or ~1) and is highest in bivalves relative to upper trophic levels. ICP-MS for Cd; DMA-80 for total Hg. Methylmercury measured by isotope-dilution GC-ICPMS in a subset. Species-level means and ranges are presented by tissue type.
Methods (brief)
ICP-MS for cadmium; DMA-80 for total mercury; GC-ICPMS for methylmercury speciation in a subset. Stable nitrogen isotopes (δ¹⁵N) used to establish trophic position. Samples collected from multiple Hudson Bay sites, Canadian Arctic.
Implications
Certification: Provides trophic-transfer context for seafood categories; bivalves (mussels) accumulate Cd at highest levels; fish at upper trophic levels accumulate MeHg. Directly relevant to seafood product-category pages. Courses: Key reference for Arctic seafood contamination module and trophic magnification discussion. App: Contributes to seafood and marine fish contamination profiles, particularly for MeHg and Cd. Microbiome: Not addressed.