Mercury Oxidation and Depletion in the Reactive Halogen Enriched Troposphere of the Dead Sea

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The aim of this study is to elucidate atmospheric conditions and chemical pathways responsible for recently observed atmospheric mercury depletion events (AMDE) at the Dead Sea in Israel. Hypotheses include: (1) depletion of gaseous elemental mercury (GEM) at the Dead Sea is accompanied by increased levels of reactive gaseous mercury (RGM) and particulate forms (PHg), which would confirm that AMDE at the Dead Sea are analogous to those observed in the polar troposphere; (2) AMDE are correlated with high levels of reactive halogen compounds (RHC), specifically BrOx (Br + BrO); (3) even small concentrations of RHC may initiate GEM oxidation, with implications for other midlatitude marine boundary layer sites with lower RHC levels. These hypotheses will be tested by simultaneous measurement of speciated mercury, halogen oxides, nitrogen oxides, ozone, sulfate aerosols, fine particulates, and meteorological parameters. A modeling study will help identify the mechanisms for reactive halogen chemistry and mercury oxidation.Knowledge of source and sink strengths of atmospheric mercury species is critical for regulatory agencies to protect humans and ecosystems from this potent toxin. The research will involve undergraduate and graduate students from the University of Nevada, Reno. A partnership will be initiated with a local (Nevada) school district to expose teachers and students to this research and expand a current collaboration with their Gifted and Talented Program.