Document Type

Honors Capstone Project

Date of Submission

Spring 5-1-2019

Capstone Advisor

Svetoslava Todorova

Honors Reader

Katie Cadwell

Capstone Major

Biomedical and Chemical Engineering

Capstone College

Arts and Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biochemistry, Biophysics, and Structural Biology | Chemistry | Life Sciences | Other Biochemistry, Biophysics, and Structural Biology

Abstract

The trophic transfer and bioaccumulation of methyl mercury (MeHg) in aquatic ecosystems is a substantial concern, resulting in fish consumption advisories worldwide. Aquatic ecosystems have been identified as the critical environments that breed production of MeHg and low levels of initial accumulation in biota. MeHg production is a microbially-mediated process, occurring primarily at the transition between oxic and anoxic environments. This research aimed to assess the extent to which dissolved organic matter (DOM) affects methylation of mercury in the oligotrophic meromictic lake, Green Lake, in Fayetteville, NY and the warm monomictic lake, Seneca Lake, in Geneva, NY. General physical parameters (pH, temperature, dissolved oxygen, and conductivity) were collected on the field. Additional water column samples were analyzed for sulfide, inorganic anions, dissolved organic carbon, total mercury, MeHg, and DOM. Redox parameters delineated a wide redox transition zone in Green Lake between 18-21 m, while the water column of Seneca Lake remained oxygenated. The highest methylation of mercury, 41-49% (determined by the percent mercury as MeHg), was found at the chemocline of Green Lake. A secondary peak of 33%MeHg was found at the 5 m depth. At these same depths, increases in readily available labile DOM were also found. Substantial methylation and increases in labile DOM were not observed in Seneca Lake. A correlation analysis determined that the changes in labile DOM explained 54% of the changes in the percent MeHg. These findings indicate that high levels of in-situ produced labile DOM stimulated methylation of mercury

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.

Available for download on Thursday, July 16, 2020

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