State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Res. 2013 Aug;125:2-11. doi: 10.1016/j.envres.2013.03.014.
Soil erosion is a main cause of land degradation, and in its accelerated form is also one of the most serious ecological environmental problems. Moreover, there are few studies on migration of mercury (Hg) induced by soil erosion in seriously Hg-polluted districts. This paper selected Wanshan Hg mining area, SW China as the study area. Revised universal soil loss equation (RUSLE) and Geographic information system (GIS) methods were applied to calculate soil and Hg erosion and to classify soil erosion intensity. Our results show that the soil erosion rate can reach up to 600,884tkm(-2)yr(-1). Surfaces associated with very slight and extremely severe erosion include 76.6% of the entire land in Wanshan. Furthermore, the cumulative erosion rates in the area impacted by extremely severe erosion make up 90.5% of the total. On an annual basis, Hg surface erosion load was predicted to be 505kgyr(-1) and the corresponding mean migration flux of Hg was estimated to be 3.02kgkm(-2)yr(-1). The erosion loads of Hg resulting from farmland and meadow soil were 175 and 319kgyr(-1) respectively, which were enhanced compared to other landscape types due to the fact that they are generally located in the steep zones associated with significant reclamation. Contributing to establish a mass balance of Hg in Wanshan Hg mining area, this study supplies a dependable scientific basis for controlling soil and water erosion in the local ecosystems. Land use change is the most effective way for reducing Hg erosion load in Wanshan mining area.
土壤侵蚀是土地退化的主要原因，在加速形式下也是最严重的生态环境问题之一。此外，在严重汞污染地区，关于土壤侵蚀引起的汞迁移的研究很少。本文选择中国西南万山汞矿区作为研究区。应用修正的通用土壤流失方程（RUSLE）和地理信息系统（GIS）方法计算土壤和汞侵蚀，并对土壤侵蚀强度进行分类。研究结果表明，土壤侵蚀速率可达 600884tkm（-2）yr（-1）。非常轻微和极度严重侵蚀的表面占万山整个土地的 76.6%。此外，受极度严重侵蚀影响的地区的累积侵蚀率占总量的 90.5%。在每年的基础上，预测汞表面侵蚀负荷为 505kgyr（-1），汞的相应平均迁移通量估计为 3.02kgkm（-2）yr（-1）。农田和草地土壤的汞侵蚀负荷分别为 175 和 319kgyr（-1），由于它们通常位于与大规模开垦相关的陡峭地带，因此与其他景观类型相比有所增加。为了在万山汞矿区建立汞的质量平衡，本研究为当地生态系统的水土保持提供了可靠的科学依据。土地利用变化是万山矿区减少汞侵蚀负荷的最有效途径。
