Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes.
Mercury (Hg) is a neurotoxin that humans are exposed to primarily through consumption of fish. Significant gaps remain in our knowledge of Hg biogeochemistry and measurement of natural abundance Hg stable isotopes is beginning to answer some of the outstanding questions. Mass-dependent fractionation...
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ftumdeepblue:oai:deepblue.lib.umich.edu:2027.42/95961 2024-01-07T09:41:57+01:00 Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. Sherman, Laura S. Blum, Joel D. Dvonch, Joseph T. Keeler, Gerald J. Basu, Niladri Ewing, Rodney C. Lohmann, Kyger C. 2012 application/pdf https://hdl.handle.net/2027.42/95961 en_US eng https://hdl.handle.net/2027.42/95961 Mercury Stable Isotopes Geology and Earth Sciences Science Thesis 2012 ftumdeepblue 2023-12-10T17:55:32Z Mercury (Hg) is a neurotoxin that humans are exposed to primarily through consumption of fish. Significant gaps remain in our knowledge of Hg biogeochemistry and measurement of natural abundance Hg stable isotopes is beginning to answer some of the outstanding questions. Mass-dependent fractionation (MDF, reported as δ202Hg) and mass-independent fractionation (MIF, reported as Δ199Hg) of Hg isotopes occur during many biogeochemical processes. To better understand Hg cycling in volcanic systems we first investigated the isotopic composition of Hg emissions from Yellowstone volcanic field. We found that the light isotopes of Hg were preferentially emitted as Hg0(g) from hydrothermal waters, suggesting that natural Hg0(g) emissions may display negative δ202Hg values. Next, we used Hg isotopes to explore the role of photochemical reactions in Arctic atmospheric mercury depletion events. We found that a significant percentage of the Hg deposited during these events is subsequently photochemically reduced and lost, producing negative MIF of Hg remaining in the snow. We also found that a portion of the reemitted Hg accumulates on nearby ice crystals. These results suggest that although a large percentage of the Hg deposited during these events is lost from the snow, a portion of the Hg is retained locally and may enter local aquatic ecosystems. Finally, we investigated whether Hg isotopes could be used to trace anthropogenic Hg emissions to deposition sites and ultimately into fish populations. We found that Hg in precipitation collected downwind of a coal-fired power plant in Florida displayed anomalously negative δ202Hg values. We then explored whether this isotopic signature could be used to trace Hg emitted by the power plant into local sport fish. Instead, we found that Hg in largemouth bass was largely derived from accumulated Hg in lake sediments. This dissertation demonstrates that measurement of natural Hg isotopes in environmental samples is a powerful tool that can be used to gain greater understanding of ... Thesis Arctic University of Michigan: Deep Blue Arctic |
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University of Michigan: Deep Blue |
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English |
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Mercury Stable Isotopes Geology and Earth Sciences Science |
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Mercury Stable Isotopes Geology and Earth Sciences Science Sherman, Laura S. Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
topic_facet |
Mercury Stable Isotopes Geology and Earth Sciences Science |
description |
Mercury (Hg) is a neurotoxin that humans are exposed to primarily through consumption of fish. Significant gaps remain in our knowledge of Hg biogeochemistry and measurement of natural abundance Hg stable isotopes is beginning to answer some of the outstanding questions. Mass-dependent fractionation (MDF, reported as δ202Hg) and mass-independent fractionation (MIF, reported as Δ199Hg) of Hg isotopes occur during many biogeochemical processes. To better understand Hg cycling in volcanic systems we first investigated the isotopic composition of Hg emissions from Yellowstone volcanic field. We found that the light isotopes of Hg were preferentially emitted as Hg0(g) from hydrothermal waters, suggesting that natural Hg0(g) emissions may display negative δ202Hg values. Next, we used Hg isotopes to explore the role of photochemical reactions in Arctic atmospheric mercury depletion events. We found that a significant percentage of the Hg deposited during these events is subsequently photochemically reduced and lost, producing negative MIF of Hg remaining in the snow. We also found that a portion of the reemitted Hg accumulates on nearby ice crystals. These results suggest that although a large percentage of the Hg deposited during these events is lost from the snow, a portion of the Hg is retained locally and may enter local aquatic ecosystems. Finally, we investigated whether Hg isotopes could be used to trace anthropogenic Hg emissions to deposition sites and ultimately into fish populations. We found that Hg in precipitation collected downwind of a coal-fired power plant in Florida displayed anomalously negative δ202Hg values. We then explored whether this isotopic signature could be used to trace Hg emitted by the power plant into local sport fish. Instead, we found that Hg in largemouth bass was largely derived from accumulated Hg in lake sediments. This dissertation demonstrates that measurement of natural Hg isotopes in environmental samples is a powerful tool that can be used to gain greater understanding of ... |
author2 |
Blum, Joel D. Dvonch, Joseph T. Keeler, Gerald J. Basu, Niladri Ewing, Rodney C. Lohmann, Kyger C. |
format |
Thesis |
author |
Sherman, Laura S. |
author_facet |
Sherman, Laura S. |
author_sort |
Sherman, Laura S. |
title |
Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
title_short |
Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
title_full |
Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
title_fullStr |
Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
title_full_unstemmed |
Understanding Sources and Cycling of Mercury using Mercury Stable Isotopes. |
title_sort |
understanding sources and cycling of mercury using mercury stable isotopes. |
publishDate |
2012 |
url |
https://hdl.handle.net/2027.42/95961 |
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Arctic |
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Arctic |
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Arctic |
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Arctic |
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https://hdl.handle.net/2027.42/95961 |
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1787422779357790208 |