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Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation.
- Source :
-
Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2017 Jan; Vol. 220 (Pt B), pp. 1359-1365. Date of Electronic Publication: 2016 Nov 09. - Publication Year :
- 2017
-
Abstract
- Atmospheric deposition of mercury (Hg) to surface water is one of the dominant sources of Hg in aquatic environments and ultimately drives methylmercury (MeHg) toxin accumulation in fish. It is known that freshly deposited Hg is more readily methylated by microorganisms than aged or preexisting Hg; however the underlying mechanism of this process is unclear. We report that Hg bioavailability is decreased by photochemical reactions between Hg and dissolved organic matter (DOM) in water. Photo-irradiation of Hg-DOM complexes results in loss of Sn(II)-reducible (i.e. reactive) Hg and up to an 80% decrease in MeHg production by the methylating bacterium Geobacter sulfurreducens PCA. Loss of reactive Hg proceeded at a faster rate with a decrease in the Hg to DOM ratio and is attributed to the possible formation of mercury sulfide (HgS). These results suggest a new pathway of abiotic photochemical formation of HgS in surface water and provide a mechanism whereby freshly deposited Hg is readily methylated but, over time, progressively becomes less available for microbial uptake and methylation.<br /> (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Subjects :
- Biological Availability
Mercury chemistry
Mercury metabolism
Methylation
Methylmercury Compounds chemistry
Methylmercury Compounds metabolism
Water chemistry
Water Microbiology
Water Pollutants, Chemical chemistry
Water Pollutants, Chemical metabolism
Bacteria metabolism
Mercury analysis
Methylmercury Compounds analysis
Photochemical Processes
Water Pollutants, Chemical analysis
Subjects
Details
- Language :
- English
- ISSN :
- 1873-6424
- Volume :
- 220
- Issue :
- Pt B
- Database :
- MEDLINE
- Journal :
- Environmental pollution (Barking, Essex : 1987)
- Publication Type :
- Academic Journal
- Accession number :
- 27836473
- Full Text :
- https://doi.org/10.1016/j.envpol.2016.10.099