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dc.contributor.authorBrown, Megan Elizabethen_US
dc.date.accessioned2014-03-14T20:37:44Z
dc.date.available2014-03-14T20:37:44Z
dc.date.issued2004-05-11en_US
dc.identifier.otheretd-05202004-174341en_US
dc.identifier.urihttp://hdl.handle.net/10919/33028
dc.description.abstractThis study utilized freshwater mussel shells to assess the role of mercury contamination in the North Fork Holston River, an aquatic habitat affected by extensive extirpations of mussel populations starting in the early 1970â s. Mussel shells (n=366) collected from 5 sites, upstream and downstream of Saltville (where mercury was used from 1950-1972) were analyzed to test if: (1) geochemical signatures of shells record variation in mercury levels relative to the contamination source; and (2) shell taphonomy could be used to differentiated affected and unaffected sites. Analysis of 40 shells for geochemical signatures using atomic absorption spectroscopy indicated a strong longitudinal pattern. Mercury content was as follows: upstream sites had low Hg concentrations (<5 to 31ppb), shells directly below Saltville had high concentrations (23-4,637ppb), shells 18km downstream of Saltville displayed intermediate values (7-115ppb), and those 38.4km downstream were comparable to upstream sites (<10ppb). Two pre-industrial shells collected from Saltville in 1917 also yielded Hg estimates (5-6ppb) comparable with upstream estimates. The Hg content was not correlated with shell length (r=-0.3; p=0.2) or degree of taphonomic alteration (r=0.18; p=0.28). Analysis of 366 shells for taphonomic signatures indicated that shells are most heavily altered and fragmented directly downstream of Saltville. In contrast, upstream sites, inhabited by reproducing mussel populations, contain many fresh-dead shells. Taphonomic signatures can thus be used to differentiate sites with different extirpation histories. Relic mussel shells can provide useful spatial and temporal data on Hg concentrations in polluted ecosystems and offer a tool for delineating areas with unknown extirpation histories.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartThesis-2.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectVirginiaen_US
dc.subjectmollusksen_US
dc.subjecttaphonomyen_US
dc.subjectpollutionen_US
dc.subjectextirpationen_US
dc.titleGeochemical and Taphonomic Signatures of Freshwater Mussel Shells as Evidence of Mercury-Related Extirpations in the North Fork Holston River, Virginiaen_US
dc.typeThesisen_US
dc.contributor.departmentGeosciencesen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeosciencesen_US
dc.contributor.committeechairKowalewski, Michalen_US
dc.contributor.committeememberSchreiber, Madeline E.en_US
dc.contributor.committeememberCherry, Donald S.en_US
dc.contributor.committeememberNeves, Richard J.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05202004-174341/en_US
dc.date.sdate2004-05-20en_US
dc.date.rdate2005-06-10
dc.date.adate2004-06-10en_US


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