Abstract
The potential net MeHg formation in water bodies and surface sediments was investigated. The radiochemical method was applied to the methylation assays performedin situ. The role of sulfate reducing bacteria and overall bacteria activity in the methylation process was examined by molybdate and formaldehyde addition, respectively. The impact of light conditions was tested by light and dark incubations. Low but detectable methylation was found in the oxic epilimnion of all lakes. The rates were affected neither by molybdate nor by formaldehyde. The highest rates were observed in the hypolimnion within the sulfide maxima. Near the sediment surface the rates again declined. Usually, the methylation rates in sediments were of the same level as the rates the anoxic water. Formaldehyde prevented methylation in the anoxic water and sediment. Molybdate inhibited methylation in sediments but in the sulfidic waters the inhibition was only partial or the methylation process was stimulated by molybdate. No significant differences in methylation activity were found between the natural light and the dark bottle incubations. The highest methylation rates were not always concomitant with the highest MeHg concentrations, the highest concentrations more likely to be found in the particle rich water layers. The results show that MeHg in sulfidic waters was formed biotically by sulfate reducing bacteria which were competing with methanogens for acetate and hydrogen under sulfate limiting conditions.
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References
Bloom, N. S., Watras, C. J. and Hurley, J. P.: 1991,Water, Air, and Soil Pollution 56, 477–491.
Compeau, G., and Bartha, R.: 1985,Appl. Environ. Microbiol. 50, 498–502.
Eloranta, P.:1985,Arch. Hydrobiol. Suppl. 71(3), 459–469.
Furutani, A. and Rudd, J. W. M.: 1980,Appl. Environ. Microbiol. 40, 770–776.
Gadd, G. M.: 1992,FEMS Microbiol. Lett. 100, 197–204.
Gelwicks, J. T., Risatti, J. B. and Hayes, J. M.:1994,Appl. Environ. Microbiol. 60, 467–472.
Gilmour, C. C. and Henry, E. A.: 1991,Environmental Pollution 71, 131–169.
Gilmour, C. C., Henry, E. A., Mitchell, R.: 1992,Environ. Sci. Technol. 26, 2281–2287.
Imura, N., Sukegava, E., Pan, S.,et al.: 1971,Science 172, 1248–1249.
Jones, J. G. and Simon, B. M.: 1984,FEMS Microbiol. Lett. 21, 47–50.
Lee, B-G. and Fisher, N. S.: 1992,Limnol. Oceanogr. 37(7), 1345–1360.
Lee, B-G. and Fisher, N. S.: 1992,Limnol. Oceanogr. 38(8), 1593–1602.
Lovely, D. R. and Klug, M. K.: 1983,Appl. Environ. Microbiol. 45, 187–192.
Mason, R. P., Fitzgerald, W. F., Hurley, J.,et al.: 1993,Limnol. Oceanogr. 38(6), 1227–1241.
Parkman, H., Östlund, P., Samuelsson, M-O.,et al.: 1994,Mercury Pollution: Integration and Synthesis, Lewis Publishers, (in press).
Vena, M., Matilainen, T., Porvari, P.,et al.: 1994,Mercury Pollution: Integration and Synthesis, Lewis Publishers, (in press).
Verta, M. and Matilainen, T.: 1994, this volume.
Watras, C. J., Bloom, N. S.: 1994,Mercury Pollution: Integration and Synthesis, Lewis Publishers, (in press).
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Matilainen, T. Involvement of bacteria in methylmercury formation in anaerobic lake waters. Water Air Soil Pollut 80, 757–764 (1995). https://doi.org/10.1007/BF01189727
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DOI: https://doi.org/10.1007/BF01189727