Articles online

Speciation of Mercury (II) and Methylmercury in Cloud and Fog Water

Category: Articles

Volume: 11 | Issue: 2 | Pages: 161-169
DOI: 10.4209/aaqr.2010.08.0067
PDF | Supplemental material | RIS | BibTeX

D.R. Bittrich1, S.P. Chadwick1, C.L. Babiarz1, H. Manolopoulos1, A.P. Rutter1, J.J. Schauer 1, D.E. Armstrong1, J. Collett2, P. Herckes3

  • 1 Environmental Chemistry and Technology Program, University of Wisconsin, Madison, 660 North Park Street, Madison, WI 53706, U.S.A.
  • 2 Department of Atmospheric Science, Colorado State University, 200 West Lake Street, Fort Collins, CO 80523, U.S.A.
  • 3 Department of Chemistry and Biochemistry, Arizona State University, PO Box 871604, Tempe, AZ 85287-1604, USA


The fate of oxidized mercury (Hg) in clouds and fogs is affected by the complexation of oxidized Hg(II) with other chemical species present in cloud and fog water. Metal complexation often influences the types of reactions available to a metal in an aqueous system. The influence of pH, major inorganic ions, and organic acids on the complexation of Hg(II) and methylmercury (MeHg) was examined for a range of cloud and fog water compositions. Fog water was collected in the San Joaquin Valley, CA and rain water was collected at Devil’s Lake State Park, WI to provide additional measurements of the chemical conditions of atmospheric media. A thermodynamic model was used to determine the speciation of Hg(II) and methylmercury (MeHg) over a range of atmospherically-relevant cloud and fog compositions. The speciation of Hg(II) in cloud and fog water was highly dependent on pH. For conditions found in most clouds and fogs, the chloride ion was the most important major ion controlling Hg(II) complexation, even under conditions of relatively low chloride content. However, Hg(OH)2(aq), and HgClOH(aq) were found to dominate over HgCl2 in locations with high pH due emissions of agricultural ammonia; i.e. San Joaquin and Sacramento Valleys, CA. At concentrations relevant to typical cloud and fog waters, carboxylic acids (e.g. formate and acetate) did not play a significant role in Hg(II) speciation. Methyl mercury was speciated as MeHgCl in most locations, except for the locations with high pH, where MeHgOH dominated. These results provide constraints over potential reaction pathways that may transform oxidized Hg(II) in clouds and fogs.


Mercury Methylmercury Atmosphere Rain Complexation

Related Article

Photodecomposition of Methylmercury in Atmospheric Waters

D.R. Bittrich, A.P. Rutter, B.D. Hall, J.J. Schauer
Volume: 11 | Issue: 3 | Pages: 290-298
DOI: 10.4209/aaqr.2010.11.0096
PDF | Supplemental material

Critical Emissions from the Largest On-Road Transport Network in South Asia

Saroj Kumar Sahu , Gufran Beig, Neha Parkhi
Volume: 14 | Issue: 1 | Pages: 135-144
DOI: 10.4209/aaqr.2013.04.0137

Ambient Air Quality during Diwali Festival over Kolkata – A Mega-City in India

A. Chatterjee , C. Sarkar, A. Adak, U. Mukherjee, S.K. Ghosh, S. Raha
Volume: 13 | Issue: 3 | Pages: 1133-1144
DOI: 10.4209/aaqr.2012.03.0062

Exploring the Variation between EC and BC in a Variety of Locations

Gbenga Oladoyin Salako, Philip K. Hopke , David D. Cohen, Bilkis A. Begum, Swapan K. Biswas, Gauri Girish Pandit, Yong-Sam Chung, Shamsiah Abd Rahman, Mohd Suhaimi Hamzah, Perry Davy, Andreas Markwitz, Dagva Shagjjamba, Sereeter Lodoysamba, Wanna Wimolwattanapun, Supamatthree Bunprapob
Volume: 12 | Issue: 1 | Pages: 1-7
DOI: 10.4209/aaqr.2011.09.0150