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Mercury stable isotope approaches to the study of monomethylmercury in the environment
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Janssen, Sarah Elizabeth. Mercury stable isotope approaches to the study of monomethylmercury in the environment. Retrieved from https://doi.org/doi:10.7282/T3J67K35

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TitleMercury stable isotope approaches to the study of monomethylmercury in the environment
NameJanssen, Sarah Elizabeth (author); Reinfelder, John R (chair); Barkay, Tamar (internal member); Yee, Nathan (internal member); Blum, Joel D (outside member); Rutgers University; Graduate School - New Brunswick
Date Created2016
Other Date2016-05 (degree)
SubjectEnvironmental Sciences, Mercury--Isotopes, Mercury--Environmental aspects
Extent1 online resource (xi, 143 p. : ill.)
DescriptionMercury stable isotopes provide additional insights into the biogeochemical cycling of mercury, but the isotopic composition of MeHg in the environment is understudied. The overall objective of this work was to examine the mercury isotopic composition of MeHg in the microorganisms (anaerobic bacteria) and environmental matrices (anoxic sediment) in which it is formed, in order to understand what controls the isotopic composition of MeHg in aquatic systems. A system for the quantitative separation of MeHg for isotope analysis that did not cause fractionation of mercury isotopes was built and tested (Chapter 2). Methylmercury from estuarine sediments had 202Hg values that varied from −0.41 to +0.41‰ and were generally higher, and spatially and temporally more variable, than those for total Hg (−0.21 to −0.48‰). This work provided a reproducible and precise method for measuring MeHg isotopes in complex matrices and also represents the first high precision isotope measurement of MeHg in sediments. The mercury isotopic composition of MeHg was estimated in fish tissue and compared to sediment MeHg measurements in order to gain insight about feeding locality of white perch and killifish species (Chapter 3). Localized estuarine fish showed similarities between the isotopic composition of MeHg in their tissue and sediment from their capture location. Migratory species were isotopically heavier than sediment MeHg, indicating different feeding areas or mercury sources. This study provides mercury stable isotope data on estuarine species and an improved estimation for isotopic composition of MeHg in fish tissue to aid in source tracking applications. Mercury isotope fractionation factors during microbial mercury methylation were determined in pure cultures of a sulfate-reducing and an iron-reducing bacterium (Chapter 4). Both bacteria had similar fractionation factors despite differences in methylation rates. The mercury stable isotope composition (202Hg) of MeHg produced by these organisms eventually exceeded that of the initial Hg(II) provided, indicating that the organisms accessed an intra- or extracellular pool of Hg that was enriched in 202Hg. This study is the first to establish both a fractionation factor for methylation in an iron-reducing bacterium and observe an isotopically-enriched pool of bioavailable Hg(II).
NotePh.D.
NoteIncludes bibliographical references
Noteby Sarah Elizabeth Janssen
Genretheses, ETD doctoral
Persistent URLhttps://doi.org/doi:10.7282/T3J67K35
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.
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