Date of Graduation

2007

Document Type

Thesis

Degree Type

MS

Committee Chair

Dorothy Vesper

Abstract

Diel (24-hour) cycling of dissolved ions has been linked to various mechanisms such as fluctuations in temperature and photosynthetically-mediated pH. Yttrium and the rare earth elements (YREE) appear to fluctuate in response to temperature. After selecting a field site based on pH and temperature screening, five sampling events were undertaken: each involved hourly or bihourly sampling with concurrent stage, pH and temperature logging. For all events, YREE increased during the nighttime and decreased during the daytime. Dissolved Fe and Mn exhibited similar trends at one of the two sampled locations. Speciation models suggest that sulfate and carbonate-bound YREE species dominate over free ion species. Calculated adsorption enthalpies are similar to previously determined field values. Diel YREE cycle magnitude appears to decrease in response to a decrease in Fe load. The results of these experiments indicate that diel cycles of YREE, Fe and Mn occur in the coal mine drainage setting.

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