Atmospheric Hg(0) dry deposition over environmental surfaces: Insights from mercury isotope fractionation

Atmospheric Hg(0) dry deposition is a vital process that significantly affects the global distribution and cycling of Hg. However, significant knowledge gaps and challenges persist in understanding atmospheric Hg(0) deposition and its subsequent post-deposition processes. Hg isotope fractionation has emerged as the most powerful tool for evaluating the impact of atmospheric Hg(0) deposition and unraveling key processes associated with it. By focusing on Hg isotope fractionation processes, Hg isotope compositions, and influencing factors, this review presents current knowledge, recent advancements, and new insights on atmospheric Hg(0) deposition and post-deposition processes over vegetation, soil, snow, and water surfaces. This review also points out the knowledge gaps pertaining to atmospheric Hg(0) deposition and highlights the need for further investigations into the associated processes, mechanisms, isotope fractionation, and modeling. Further research into Hg isotope fractionation in atmospheric Hg(0) deposition and post-deposition processes will advance source and process tracing, paleoclimate reconstruction, and the modeling of Hg isotope distribution on regional and global scales.