Abstract
Abstract. Isotopic compositions of Mercury (Hg) in atmospheric particles (HgPM) are probably the mixed results of emission sources and atmospheric processes. Here, we present Hg isotopic compositions in daily fine particles (PM2.5) collected from an industrial site (Chunxiao – CX) and a nearby mountain site (Daimeishan – DMS) in a coastal area of East China, and in surface seawater close to the industrial area, to reveal the influence of anthropogenic emission sources and atmospheric transformations on Hg isotopes. The PM2.5 samples displayed a significant spatial difference in δ202Hg. For the CX site, the negative δ202Hg values are similar to those of source materials, and the HgPM contents were well correlated with chemical tracers, indicating the dominant contributions of local industrial activities to HgPM2.5, whereas the observed positive δ202Hg at the DMS site was likely associated with regional emissions and extended atmospheric processes during transport. The Δ199Hg values in PM2.5 from the CX and DMS sites were comparably positive. The unity slope of Δ199Hg versus Δ201Hg over all data suggests that the odd mass independent fractionation (MIF) of HgPM2.5 was primarily induced by the photoreduction of Hg2+ in aerosols. The positive Δ200Hg values with a minor spatial difference were probably associated with the photooxidation of Hg0, which is generally enhanced in the coastal environment. Total Hg in offshore surface seawater was characterized by negative δ202Hg and near-zero Δ199Hg and Δ200Hg values, which are indistinguishable from Hg isotopes of source materials. Overall, the PM2.5 collected from industrial areas had comparable δ202Hg values but more positive Δ199Hg and Δ200Hg as compared to surface seawater. The results indicate that atmospheric transformations would induce the significant fractionation of Hg isotopes and obscure the Hg isotopic signatures of anthropogenic emissions.
Highlights
Mercury (Hg) is a genotoxic element and was ranked with the priority-controlled pollutants in many countries
HgPM can be formed by the uptake of gaseous oxidized mercury (GOM) in particles, which made an important contribution to HgPM in the heavily particle polluted areas (Xu et al, 2020), whereas the reduction of GOM binding with dissolved organic carbon ligands in aqueous particles potentially converts it back to the gas phase (Horowitz et al, 2017)
The research has suggested that atmospheric HgPM is generally a combined result of anthropogenic emissions and atmospheric processes, which plays a crucial role in the global cycling of Hg
Summary
Mercury (Hg) is a genotoxic element and was ranked with the priority-controlled pollutants in many countries. A previous study conducted in remote areas of China has reported that the HgPM exposed to air masses of regional and long-range sources had distinct isotopic signatures (Fu et al, 2019). These studies have implied that the long-range transboundary Hg transport from southern Asia played a crucial role in the Himalaya and the Tibetan Plateau and even in southwestern and northwestern China (Fu et al, 2019; Guo et al, 2021, 2022). The objectives of this study are (1) to differentiate the Hg isotopes in PM2.5 from the two neighboring industrial and mountain sites, (2) to use the Hg isotopes to explore the influence of anthropogenic sources on the HgPM, and (3) to reveal the role of atmospheric transformations in varying HgPM isotopic compositions.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
