Effects of mercury, organic carbon, and microbial inhibition on methylmercury cycling at the profundal sediment-water interface of a sulfate-rich hypereutrophic reservoir
| Autor: | Jeffery Pasek, Sarah Brower, Byran C. Fuhrmann, Peggy A. O'Day, Marc W. Beutel, Christian Tran, Mark Seelos, Andrew Funk |
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| Rok vydání: | 2020 |
| Předmět: |
Geologic Sediments
010504 meteorology & atmospheric sciences Health Toxicology and Mutagenesis chemistry.chemical_element 010501 environmental sciences Toxicology 01 natural sciences chemistry.chemical_compound Humans Profundal zone Sulfate Methylmercury Ecosystem 0105 earth and related environmental sciences Total organic carbon Sulfates Water General Medicine Mercury Methylmercury Compounds Pollution Carbon Mercury (element) chemistry Environmental chemistry Bioaccumulation Anaerobic bacteria Microcosm Water Pollutants Chemical |
| Zdroj: | Environmental pollution (Barking, Essex : 1987). 268 |
| ISSN: | 1873-6424 |
| Popis: | Methylmercury (MeHg) produced by anaerobic bacteria in lakes and reservoirs, poses a threat to ecosystem and human health due to its ability to bioaccumulate in aquatic food webs. This study used 48-hr microcosm incubations of profundal sediment and bottom water from a sulfate-rich, hypereutrophic reservoir to assess seasonal patterns of MeHg cycling under various treatments. Treatments included addition of air, Hg(II), organic carbon, and microbial inhibitors. Both aeration and sodium molybdate, a sulfate-reducing bacteria (SRB) inhibitor, generally decreased MeHg concentration in microcosm water, likely by inhibiting SRB activity. The methanogenic inhibitor bromoethanesulfonate increased MeHg concentration 2- to 4- fold, suggesting that methanogens were potent demethylators. Pyruvate increased MeHg concentration under moderately reduced conditions, likely by stimulating SRB, but decreased it under highly reduced conditions, likely by stimulating methanogens. Acetate increased MeHg concentration, likely due to the stimulation of acetotrophic SRB. Results suggest that iron-reducing bacteria (IRB) were not especially prominent methylators and MeHg production at the sediment-water interface is elevated under moderately reduced conditions corresponding with SRB activity. In contrast, it is suppressed under oxic conditions due to low SRB activity, and under highly reduced conditions ( |
| Databáze: | OpenAIRE |
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