Direct observations of atmospheric oxidized mercury speciation in polar areas.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41946705.
- Also identified by DOI 10.1038/s41467-026-71146-z and PMC identifier 13057356.
- Licence recorded as CC BY-NC-ND.
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Abstract
Mercury is a persistent pollutant with significant public health impacts in polar regions where fish consumption drives human exposure. Atmospheric oxidation pathways control where mercury deposits globally, but the lack of molecular-level observations of oxidized mercury products has hindered the validation of proposed chemical mechanisms. Here, we show the in-situ online detection of individual mercuric halides (HgCl<sub>2</sub>, BrHgCl, HgBr<sub>2</sub>, ClHgI, BrHgI, and HgI<sub>2</sub>) in the polar boundary layer using atmospheric pressure chemical ionization mass spectrometry. Our observations identify HgBr<sub>2</sub> as the dominant oxidized mercury species at both poles, while HgCl<sub>2</sub> and other halides were also observed in Antarctica. The observed speciation diverges from current model predictions, which favor HgCl<sub>2</sub> and HOHgBr as dominant oxidized forms. Our results show that real-time molecular measurements can substantially advance global mercury monitoring and improve the chemical models used to assess environmental policies and predict deposition patterns.