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Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity

Environmental Science and Technology

By:
, , , , , , and
DOI: 10.1021/es300794q

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Abstract

We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on unamended food pellets (0.1 μg/g MeHg) or was switched to food pellets with 1.0 μg/g or 4.0 μg/g of added MeHg, for a period of 2 months. The difference in δ202Hg (MDF) and Δ199Hg (MIF) between fish tissues and food pellets with added MeHg was within the analytical uncertainty (δ202Hg, 0.07 ‰; Δ199Hg, 0.06 ‰), indicating no isotope fractionation. In experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ202Hg and Δ199Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting reequilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity
Series title:
Environmental Science and Technology
DOI:
10.1021/es300794q
Volume
46
Issue:
14
Year Published:
2012
Language:
English
Publisher:
American Chemical Society
Publisher location:
Washington, D.C.
Contributing office(s):
Great Lakes Science Center
Description:
8 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Science and Technology
First page:
7527
Last page:
7534