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Comparison of gaseous oxidized Hg measured by KCl-coated denuders, and nylon and cation exchange membranes.
Environ Sci Technol ; 47(13): 7307-16, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23651121
ABSTRACT
The chemical compounds that make up gaseous oxidized mercury (GOM) in the atmosphere, and the reactions responsible for their formation, are not well understood. The limitations and uncertainties associated with the current method applied to measure these compounds, the KCl-coated denuder, are not known due to lack of calibration and testing. This study systematically compared the uptake of specific GOM compounds by KCl-coated denuders with that collected using nylon and cation exchange membranes in the laboratory and field. In addition, a new method for identifying different GOM compounds using thermal desorption is presented. Different GOM compounds (HgCl2, HgBr2, and HgO) were found to have different affinities for the denuder surface and the denuder underestimated each of these compounds. Membranes measured 1.3 to 3.7 times higher GOM than denuders in laboratory and field experiments. Cation exchange membranes had the highest collection efficiency. Thermodesorption profiles for the release of GOM compounds from the nylon membrane were different for HgO versus HgBr2 and HgCl2. Application of the new field method for collection and identification of GOM compounds demonstrated these vary as a function of location and time of year. Understanding the chemistry of GOM across space and time has important implications for those developing policy regarding this environmental contaminant.
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Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Assunto principal: Óxidos / Brometos / Monitoramento Ambiental / Compostos de Mercúrio / Poluentes Atmosféricos / Cloreto de Mercúrio Idioma: Inglês Revista: Environ Sci Technol Ano de publicação: 2013 Tipo de documento: Artigo País de afiliação: Estados Unidos