广西土壤和沉积物砷含量及污染分布特征

广西素有“有色金属之乡”美誉,土壤重金属污染问题较为突出。通过总结1989年以来相关文献,探讨了广西土壤和沉积物中砷含量及污染分布特征。3 045个和477个土壤和沉积物有效样点的统计分析表明,广西砷污染土壤主要分布于桂西北地区,尤其是刁江及金城江流域;矿业活动显著影响土壤砷积累,从其均值看：工矿区非农用土壤（140.5 mg/kg）>工矿区农用土壤（80.68 mg/kg）>非工矿区农用土壤（19.11 mg/kg）>城区土壤（18.35 mg/kg）,重度砷污染农用地样本均来自南丹;工矿区河流沉积物砷含量（283.5 mg/kg）远高于非工矿区,主要受影响区分布在刁江及大环江流域。为了控制环境风险,建议开展主要水系沉积物砷污染详查,加强南丹及周边区域污染防控和污染土壤修复。

Contents and Pollution Distribution Characteristics of Arsenic in Soils and Sediments in Guangxi Zhuang Autonomous Region

Guangxi was known as “the hometown of nonferrous metals”, and the problem of heavy metal pollution in soil was very prominent. Based on the published papers about arsenic(As) in Guangxi since 1989 and our previous work in Guilin, Nandan and Huanjiang, this study explored the concentration and pollution distribution of As in soils and sediments in Guangxi. Totally, 3 045 soil samples and 477 sediment samples were collected. Results showed that: 1) In Guangxi, the As polluted soil mainly distributed in the northwest of Guangxi, especially in the Diaojiang and Jinchengjiang River basins. 2) Mining activity affected the accumulation of As in soil significantly. The soils with concentrations of As from high to low in order were non-agricultural soil in industrial and mining areas (140.5 mg/kg), agricultural soil in industrial and mining areas (80.68 mg/kg), agricultural soil in non-industrial and mining areas (19.11 mg/kg) and urban soil (18.35 mg/kg). Compared with the standard of soil environment quality in China (GB15618-1995), 89.4%, 69.0%, 18.7% and 12.1% of the above four types of soil samples exceeded the standard limit. The most seriously polluted samples in agricultural soil were all in Nandan. 3) The accumulation of As in marine sediments (8.76 mg/kg) and river sediments in non-industrial and mining areas (16.11 mg/kg) were not remarkable. As for river sediments, the pollution levels of As in industrial and mining areas (283.5 mg/kg) were much higher than those in non-industrial and mining areas. The affected areas mainly distributed in the Diaojiang and Dahuanjiang basins. In order to control the environmental risk, it is recommended to carry out the survey of As pollution in the surface sediments of the main river systems in Guangxi, especially in the river of Diaojiang, Dahuanjiang and Jinchengjiang, and the pollution in Nandan areas should be controlled and prevented and the contaminated soil should be repaired.