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Photoinduced reduction of divalent mercury in ice by organic matter

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Title: Photoinduced reduction of divalent mercury in ice by organic matter
Authors: Bartels-Rausch, Thorsten1 thorsten.bartels-rausch@psi.ch, Krysztofiak, Gisèle2, Bernhard, Andreas3, Schläppi, Manuel1,3, Schwikowski, Margit1,3, Ammann, Markus1
Source: Chemosphere. Jan2011, Vol. 82 Issue 2, p199-203. 5p.
Subjects: Photochemistry, Chemical reduction, Mercury (Element), Organic compounds, Reaction mechanisms (Chemistry), Food chains, Oxalic acid, Temperature effect
Abstract: Abstract: Reduction of divalent mercury and subsequent emission to the atmosphere has been identified as loss process from surface snow, but its mechanism and importance are still unclear. The amount of mercury that stays in the snow pack until spring is of significance, because during snow melt it may be released to the aquatic environment and enter the food web. Better knowledge of its fate in snow might further assist the interpretation of ice core data as paleo-archive. Experiments were performed under well-controlled laboratory conditions in a coated wall flow tube at atmospheric pressure and irradiated with light between 300nm and 420nm. Our results show that the presence of benzophenone and of oxalic acid significantly enhances the release of mercury from the ice film during irradiation, whereas humic acid is less potent to promote the reduction. Further it was found that oxygen or chloride, and acidic conditions lowered the photolytically induced mercury release in the presence of benzophenone, while the release got larger with increasing temperatures. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Abstract: Reduction of divalent mercury and subsequent emission to the atmosphere has been identified as loss process from surface snow, but its mechanism and importance are still unclear. The amount of mercury that stays in the snow pack until spring is of significance, because during snow melt it may be released to the aquatic environment and enter the food web. Better knowledge of its fate in snow might further assist the interpretation of ice core data as paleo-archive. Experiments were performed under well-controlled laboratory conditions in a coated wall flow tube at atmospheric pressure and irradiated with light between 300nm and 420nm. Our results show that the presence of benzophenone and of oxalic acid significantly enhances the release of mercury from the ice film during irradiation, whereas humic acid is less potent to promote the reduction. Further it was found that oxygen or chloride, and acidic conditions lowered the photolytically induced mercury release in the presence of benzophenone, while the release got larger with increasing temperatures. [ABSTRACT FROM AUTHOR]
ISSN:00456535
DOI:10.1016/j.chemosphere.2010.10.020