Distribution, alkylation, and migration of mercury in soil discharged from the Itomuka mercury mine
Distribution, alkylation, and migration of mercury in soil discharged from the Itomuka mercury mine
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糸冢汞矿排放土壤中汞的分布、烷基化和迁移
DOI：
10.1016/j.scitotenv.2021.152492
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Takashi Tomiyasu
中科院分区：
文献类型：
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作者：
Hitoshi Kodamatani;Azusa Shigetomi;Junna Akama;Ryo Kanzaki;Takashi Tomiyasu
本研究的目的是调查以前排放的汞（Hg）从Itomuka汞矿释放到周围环境中，特别是到土壤中的行为。矿区周围8个采样点表层土壤中总汞、甲基汞和乙基汞的含量分别为3.8- 64.2mg/kg、6.0-54.7 μg/kg和4.5 μg/kg。从8个样点中的7个样点采集的岩芯样品表明，T-Hg的垂直分布在表层最高，在较低的层迅速下降。一个很强的正相关性之间的T-Hg和甲基汞浓度的核心样本，但是，每个核心的回归线的斜率变化很大。这表明汞和甲基汞不是同时从大气中提供的，而是甲基汞在现场产生的。此外，MeHg和EtHg在土壤中的形成被认为是根据总有机碳/总氮比，这是土壤有机质的分解指数。T-Hg和MeHg之间的强正相关性可以归因于含汞有机质向下层的迁移。在河床采样点，T-Hg和甲基汞之间没有关系，因为在较低的土壤层中的T-Hg高，这表明汞在该采样点的矿石提供。分级实验和淋溶实验的结果支持了这些关于土壤中汞的形态变化和迁移的假设。为了了解该地区的现状，还对水、沉积物、大气和植物中的汞进行了测量。
The purpose of this study was to investigate the behavior of previously discharged mercury (Hg) released from the Itomuka Hg mine into the surrounding environment, especially into soil. Total-Hg (T-Hg), methylmercury (MeHg), and ethylmercury (EtHg) concentrations in the surface soil at eight sample sites around the mine were 3.8–64.2 mg/kg, 6.0–54.7 μg/kg, and undetected to 4.5 μg/kg, respectively. Core samples collected from seven of the eight sample sites showed that the vertical distribution of T-Hg was the highest in the surface soil layer and decreased rapidly in the lower layers. A strong positive correlation was observed between T-Hg and MeHg concentrations in the core samples; however, the slope of the regression line varied considerably for each core. This suggests that Hg and MeHg were not supplied from the atmosphere simultaneously, but rather that MeHg was produced on-site. Further, the formation of MeHg and EtHg in soil was considered in terms of the total organic carbon/total nitrogen ratio, which is a decomposition index of soil organic matter. The strong positive correlation between T-Hg and MeHg can be attributed to the migration of organic matter containing Hg species to the lower layers. There was no relationship between T-Hg and MeHg at the riverbed sample site because of the high T-Hg in the lower soil layers, suggesting that Hg was supplied by ore at this sample site. These assumptions of the formation change and migration of Hg in soil were supported by the results of the fractionation experiment and the elution test. To understand the current conditions in this area, measurements of Hg in the water, sediment, atmosphere, and plants were also conducted.