Distribution and variation of mercury in frozen soils of a high-altitude permafrost region on the northeastern margin of the Tibetan Plateau
Distribution and variation of mercury in frozen soils of a high-altitude permafrost region on the northeastern margin of the Tibetan Plateau
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DOI：
10.1007/s11356-017-9088-0
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发表时间：
2017-05
影响因子：
5.8
通讯作者：
Shiwei Sun;Shi-chang Kang;Jie Huang;Shengyun Chen;Qianggong Zhang;Junming Guo;Wenjie Liu;Bigyan Neup
中科院分区：
文献类型：
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作者：
Shiwei Sun;Shi-chang Kang;Jie Huang;Shengyun Chen;Qianggong Zhang;Junming Guo;Wenjie Liu;Bigyan Neup
青藏高原是中低纬度地区最大的冻土区，但多年冻土区汞的分布和变化规律尚不清楚。在疏勒河流域的高海拔多年冻土区，东北TP进行了广泛的土壤采样活动，在23个土坑，从12个样地。分析了土壤中汞的分布、变化及其与土壤性质的关系。结果显示，总汞浓度较低，为6.3 - 29.1 ng g−1。在大多数土壤坑的垂直剖面上观察到近地表的THg浓度的峰值，然后持续下降。THg浓度与土壤有机碳（SOC）含量和粉粒级之间存在显著正相关关系，表明SOC含量和粉粒级是影响THg空间分布的两个主导因子。土壤总汞含量随海拔升高呈下降趋势，这可能是由于高海拔地区土壤有机碳含量和粉粒级较低，土壤对汞的累积潜力较低所致。土壤（0-60 cm）中的汞含量估计约为130.6 t，疏勒河流域上游地区的高稳定性和稳定性多年冻土（H-SP）区通过多年冻土退化预计损失64.2%的汞，这表明由于持续的大范围多年冻土退化，大面积的多年冻土区可能成为全球汞排放的重要来源。
The Tibetan Plateau (TP) is home to the largest permafrost bodies at low- and mid-latitudes, yet little is known about the distribution and variation of mercury (Hg) in frozen soil of the permafrost regions. In this study, extensive soil sampling campaigns were carried out in 23 soil pits from 12 plots in a high-altitude permafrost region of the Shule River Basin, northeastern TP. Hg distribution, variation, and their dependences on soil properties were analyzed. The results have revealed that total Hg (THg) concentrations were low ranging from 6.3 to 29.1 ng g−1. A near-surface peak of THg concentrations followed by a continuous decrease were observed on the vertical profiles of most soil pits. Significant positive relationships among THg concentrations, soil organic carbon (SOC) contents, and silty fractions were observed, indicating that SOC content and silty fraction are two dominant factors influencing the spatial distribution of THg. THg concentrations in soils showed a decreasing trend with altitude, which was probably attributed to a lower soil potential to Hg accumulation under the condition of lower SOC contents and silty fractions at high altitudes. Approximately, 130.6 t Hg in soils (0–60 cm) was estimated and a loss of 64.2% of Hg from the highly stable and stable permafrost (H-SP) region via permafrost degradation was expected in the upstream regions of the Shule River Basin, indicating that the large areas of permafrost regions may become an important source of global Hg emission as a result of the ongoing widespread permafrost degradation.