Use of stable isotope signatures to determine mercury sources in the Great Lakes

Ryan F. Lepak; Runsheng Yin; David P. Krabbenhoft; Jacob M. Ogorek; John F. DeWild; Thomas M. Holsen; James P. Hurley

doi:10.1021/acs.estlett.5b00277

Use of stable isotope signatures to determine mercury sources in the Great Lakes

Environmental Science & Technology Letters

By: Ryan F. Lepak, Runsheng Yin, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, Thomas M. Holsen, and James P. Hurley

https://doi.org/10.1021/acs.estlett.5b00277

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Abstract

Sources of mercury (Hg) in Great Lakes sediments were assessed with stable Hg isotope ratios using multicollector inductively coupled plasma mass spectrometry. An isotopic mixing model based on mass-dependent (MDF) and mass-independent fractionation (MIF) (δ²⁰²Hg and Δ¹⁹⁹Hg) identified three primary Hg sources for sediments: atmospheric, industrial, and watershed-derived. Results indicate atmospheric sources dominate in Lakes Huron, Superior, and Michigan sediments while watershed-derived and industrial sources dominate in Lakes Erie and Ontario sediments. Anomalous Δ²⁰⁰Hg signatures, also apparent in sediments, provided independent validation of the model. Comparison of Δ²⁰⁰Hg signatures in predatory fish from three lakes reveals that bioaccumulated Hg is more isotopically similar to atmospherically derived Hg than a lake’s sediment. Previous research suggests Δ²⁰⁰Hg is conserved during biogeochemical processing and odd mass-independent fractionation (MIF) is conserved during metabolic processing, so it is suspected even is similarly conserved. Given these assumptions, our data suggest that in some cases, atmospherically derived Hg may be a more important source of MeHg to higher trophic levels than legacy sediments in the Great Lakes.

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Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	Use of stable isotope signatures to determine mercury sources in the Great Lakes
Series title	Environmental Science & Technology Letters
DOI	10.1021/acs.estlett.5b00277
Volume	2
Issue	12
Year Published	2015
Language	English
Publisher	American Chemical Society
Publisher location	Washington, DC
Contributing office(s)	Toxic Substances Hydrology Program, Wisconsin Water Science Center
Description	7 p.
Last page	335
Country	United States
Other Geospatial	Lake Erie, Lake Huron, Lake Michigan, Lake Ontario, Lake Superior
Online Only (Y/N)	N
Additional Online Files (Y/N)	N
Google Analytic Metrics	Metrics page