| Description |
Mercury is one of the most toxic trace elements that is found in the environment, and has no recognized biological functions. Nevertheless, it is being introduced at profoundly alarming rates through various anthropogenic activities. The global cycle of Mercury (Hg) is a result of slow and complex bio-physiochemical transformations, involving various environmental pathways, and influencing its speciatiation into the highly toxic methylated form known as methyl mercury. This has resulted in bioaccumulation and biomagnification of mercury in the various water bodies of The United States, including the Great Salt Lake (GSL), Utah. The GSL watershed and the surrounding wetlands are of critical importance, and are instrumental in the sustenance of the regional ecosystem. Recent studies have reported alarmingly high concentrations of mercury in the Great Salt Lake (GSL), posing serious questions on its ecological viability. Bacteria-mediated methylation of mercury in wetland sediments has come to be an issue of recent concern and this is the focus of interest in this study. The research approach employed involved the synoptic analysis of the Total Mercury (THg) and Methyl Mercury (MeHg) concentration in the water column and sediments of the Farmington Bay (FB) in GSL, Utah Lake, and upper and lower sections of the Jordan River. Further, sediment samples were collected at three locations from a site in the wetlands of FB duck clubs to evaluate (1) the rate of mercury methylation, and (2) the ecology of sulfate reducers, which possibly participated in mercury methylation. The total and methyl mercury concentrations in the water column of Farmington Bay analyzed were 19.05±9.48 ng/L and 1.49±1.19 ng/L, respectively; the Utah Lake water column and the corresponding sediments total and methyl mercury concentrations were 2.74±0.393ng/L, 0.0536±0.024 ng/L and 27.13±2.58 ug/Kg, 0.0717±0.0235 ^ig/Kg, respectively. In the upper section of the Jordan River, mercury concentrations in the water column and the sediments estimated were 19.95±0.78 ng/L, 0.18±0.08 ng/L and 18.5±0.282 fig/Kg, 0.021 ±0.0 (Jg/Kg, respectively while, in the lower sections were 26.9±0.78 ng/L, 0.64±0.07 ng/L and 79.05±29.63 |ng/Kg, 0.15±0.023 ug/Kg, respectively. The average mercury methylation rates for the three sites in the FB duck clubs were estimated to be 0.018±0.001 /day. The phylogenetic analysis and diversity of the sulfate reducers has been analyzed and reported. The majority of the clones belong to the family of Desulfobacteraceae, signifying that the acetate-utilizing family of Sulfate Reducing Bacteria (SRB) may be more prevalent and the phylogenetic study established diversity within the sulfate reducers belonging to the four major genuses of Desulfovibrio, Desulfobacter, and Desulfonema. |
