Journal of Atmospheric Chemistry

, Volume 60, Issue 2, pp 153–168 | Cite as

Speciation and Photochemistry of Mercury in Rainwater

  • Robert J. KieberEmail author
  • Nichole E. Parler
  • Stephen A. Skrabal
  • Joan D. Willey


Mercury speciation was determined in rainwater from 76 storms in southeastern North Carolina between September 1, 2003 and September 30, 2005. Volume-weighted average concentrations of total Hg (THg), total dissolved Hg (TDHg), particulate Hg (Hgpart) and dissolved monomethyl Hg (MMHg) were 45.5 pM, 34.8 pM, 12.0 pM and 1.1 pM respectively. TDHg accounted for 77% of THg in precipitation which is similar to Cu but significantly higher than Cr or Fe. Concentrations of the various Hg species were very similar during summer and winter indicating that there was not a dominant seasonal influence on Hg speciation in rainwater at this location. THg, TDHg, and MMHg concentrations were also not significantly impacted by storm origin suggesting that they are relatively well mixed regionally and that air mass back trajectory is not the dominant factor controlling their concentration at this location. Concentrations of TDHg and Hgpart were inversely correlated in rainwater samples subjected to irradiation with simulated sunlight, suggesting the distribution between dissolved and particulate Hg may be controlled by photochemical transformations. Unlike TDHg and Hgpart, no significant changes in MMHg were observed upon photolysis of rainwater indicating that its distribution is not significantly driven by sunlight-mediated reactions, in contrast to what has been observed in surface waters. Results presented in this study indicate that the speciation of Hg in rainwater is dynamic and is driven by a complex combination of natural and anthropogenic processes as well as interactions with sunlight.


Rainwater Mercury speciation Photochemistry 



This work was supported by NSF Grant ATM-0646153. The Marine and Atmospheric Chemistry Research Laboratory at UNC Wilmington assisted with sampling and analyses.


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Robert J. Kieber
    • 1
    Email author
  • Nichole E. Parler
    • 1
  • Stephen A. Skrabal
    • 1
  • Joan D. Willey
    • 1
  1. 1.Department of Chemistry and BiochemistryUniversity of North Carolina WilmingtonWilmingtonUSA

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