Senior Honors Projects, 2010-current

Preferred Name - First Author

Mansour, Gregory

Date of Award

Spring 2017

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Biology

Advisor(s)

W. Dean Cocking, Ph.D.

Bruce Wiggins, Ph.D.

Idell Cooper, Ph.D.

Abstract

Forest ecosystems in the Shenandoah Valley of Virginia are not directly exposed to major sources of Hg contamination. Rockingham Co was assumed to be suitable as a low-level control in comparison with sites exposed to major industrial contamination in Waynesboro VA for studies in the late 1900’s. Subsequently the presence of low level Hg from background sources has been demonstrated. This study was conducted from 2014-2016 and expanded from two sites in to four sites in 2016. A composite air index, soil, and decaying organic material “duff” were analyzed for total THg concentrations using a Perkin Elmer Flow Injection Spectrophotometer dedicated to Hg analysis. The samples were digested in hot concentrated nitric and sulfuric acid. The results demonstrated a detectable amount of THg was present within the various samples with extensive variability. This prompted the question of whether there is an ambient level of mercury in terrestrial ecosystems which are not associated with demonstrated contamination. An extensive literature search aggregated THg values from control sites used in a variety of studies. Comparing the findings with the Rockingham Co. sites indicated that the Hg presence is below the global average for control locations, yet remains detectable. None of the concentrations attained at these sites are great enough to be considered a health hazard. Annual sampling is needed to provide longitudinal data to account for seasonal variation and identify long term trends.

Available for download on Saturday, April 14, 2018

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