National Institute for Environmental Studies, 16-2 Tsukuba, Ibaraki 305-8506, Japan.
NOAA/Air Resources Laboratory (ARL), Atmospheric Sciences Modeling Division (ASMD), 5830 University Research Ct., College Park, MD 20740, USA.
Ecotoxicol Environ Saf. 2024 Oct 1;284:116993. doi: 10.1016/j.ecoenv.2024.116993. Epub 2024 Sep 10.
Our investigation seeks to uncover the intricate nature of mercury dynamics in the free troposphere through analysis of the isotopic composition of total gaseous elemental mercury (TGM) at the high altitude Mauna Loa Observatory (MLO, 3397 m) in Hawaii, USA. By focusing on this unique site, we aim to provide essential insights into the behavior and cycling of mercury, contributing valuable data to a deeper understanding of its global distribution and environmental impacts. Forty-eight hours of TGM sampling from January to September 2022 revealed significant variations in δHg (-1.86 % to -0.32 %; mean = -1.17 ± 0.65 %, 2 SD, n = 34) and small variations in ΔHg (-0.27 % to 0.04 %; mean = -0.13 ± 0.14 %, 2 SD, n = 34) and ΔHg (-0.20 % to 0.06 %; mean = -0.05 ± 0.13 %, 2 SD, n = 34). During the sampling period, GEM was negatively correlated with gaseous oxidized mercury (GOM). However, the GOM/GEM ratio was not -1, suggesting that GEM oxidation and subsequent scavenging occurred previously. The δHg isotopic compositions of TGM at MLO were different from those of reported values of high-altitude mountains; the δHg of TGM at MLO was lower than the isotopic ratios that were obtained from other mountain regions. The unique atmospheric conditions at Mauna Loa, with (upslope winds during the day and downslope winds at night, likely result in the) possibly mixing of GEMs from terrestrial (and possibly oceanic GEM emission) sources with and tropospheric sources, influencing and affect the isotopic composition. During the late summer to early fall (September 14-28), negative correlations were found between relative humidity and GOM and between particle number concentrations and ΔHg, indicating the gas-to-particle partitioning of the atmospheric mercury during this period. This study will improve our understanding on mercury dynamics of marine origin and high altitudes and shed light on its complex interactions with environmental factors.
我们的研究旨在通过分析美国夏威夷莫纳罗亚山观测站（MLO，海拔 3397 米）高层自由对流层中总气态元素汞（TGM）的同位素组成，揭示汞在自由对流层中的复杂动态变化。通过关注这个独特的地点，我们旨在为汞的行为和循环提供重要的见解，为更深入了解其全球分布和环境影响提供有价值的数据。2022 年 1 月至 9 月期间，我们对 48 小时的 TGM 进行了采样，结果表明 δHg 存在显著变化（-1.86%至-0.32%；平均值=-1.17±0.65%，2SD，n=34），ΔHg 变化较小（-0.27%至 0.04%；平均值=-0.13±0.14%，2SD，n=34），ΔHg 变化也较小（-0.20%至 0.06%；平均值=-0.05±0.13%，2SD，n=34）。在采样期间，GEM 与气态氧化汞（GOM）呈负相关。然而，GOM/GEM 比值并不为-1，这表明 GEM 发生了氧化并随后被清除。MLO 的 TGM 的 δHg 同位素组成与报告的高海拔山脉的值不同；MLO 的 TGM 的 δHg 低于从其他山区获得的同位素比值。莫纳罗亚山独特的大气条件，白天为上坡风，夜间为下坡风，可能导致陆地（和可能的海洋 GEM 排放源）和对流层源的 GEM 混合，影响并影响其同位素组成。在夏末初秋（9 月 14 日至 28 日），相对湿度与 GOM 之间以及颗粒物数浓度与 ΔHg 之间存在负相关关系，表明在此期间大气汞发生了气粒分配。本研究将提高我们对海洋起源和高海拔地区汞动态变化的认识，并阐明其与环境因素的复杂相互作用。
