Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning Normal University, Nanning, 530001, PR China; Key Laboratory of Earth Surface Process and Intelligent Simulation (Guangxi), Nanning Normal University, Nanning, 530001, PR China.
School of Geography and Planning, Nanning Normal University, Nanning, 530001, PR China.
Environ Pollut. 2020 Aug;263(Pt A):114338. doi: 10.1016/j.envpol.2020.114338. Epub 2020 Apr 3.
Cadmium (Cd) contamination in soils has become a serious and widespread environmental problem, especially in areas with high natural background Cd values, but the mechanism of Cd enrichment in these areas is still unclear. This study uses the Guangxi Zhuang Autonomous Region (Guangxi), a typical area with a high background Cd level and Cd pollution related to mining activities, as an example to explore the source and predict areas with high Cd risk in soils based on the geographical detector method. The areas with high Cd in Guangxi soils were classified into non-mining areas and mining areas according to their potential Cd sources. The results show that the rich Cd content in the soils from the non-mining area of Guangxi was mainly derived from the soil type (q = 0.34), geological age (q = 0.27), rock type (q = 0.26) and geomorphic type (q = 0.20). Specifically, the Cd content was derived from the weathering and deposition processes of carbonatite from the Carboniferous system in the karst area. The high Cd content in the soils of the mining area of Guangxi was mainly derived from the area mined for mineral resources (q = 0.08) and rock type (q = 0.05). Specifically, the Cd content was derived from the mining of lead-zinc ores. The areas in Guangxi with a high risk of Cd soil pollution are mostly concentrated in karst areas, such as Hechi, Laibin, Chongzuo, southern Liuzhou and Baise, northern Nanning city and northeastern Guilin city, and some mining areas. These results indicated that the high Cd concentration in the soils of large areas of Guangxi is probably due to natural sources, while the high Cd concentration around mining areas is due to anthropogenic sources. The results will be useful for soil restoration and locating and controlling contaminated agricultural land.
镉（Cd）污染已成为土壤中一个严重且广泛存在的环境问题，尤其是在天然背景镉含量较高的地区，但这些地区镉富集的机制仍不清楚。本研究以广西壮族自治区（广西）为例，该地区是一个具有高背景镉水平和与采矿活动相关的镉污染的典型地区，利用地理探测器方法探讨土壤中镉的来源和预测高镉风险区。根据潜在镉源，将广西土壤中高镉区分为非矿区和矿区。结果表明，广西非矿区土壤中丰富的镉含量主要来源于土壤类型（q=0.34）、地质年代（q=0.27）、岩石类型（q=0.26）和地貌类型（q=0.20）。具体而言，镉含量来源于石炭系碳酸岩的风化和沉积过程。广西矿区土壤中高镉含量主要来源于矿区面积（q=0.08）和岩石类型（q=0.05）。具体而言，镉含量来源于铅锌矿的开采。广西土壤镉污染高风险区主要集中在岩溶地区，如河池、来宾、崇左、南部柳州和百色、南宁北部和桂林东北部，以及一些矿区。这些结果表明，广西大部分地区土壤中高镉浓度可能是由于自然来源，而矿区周围高镉浓度则是人为来源造成的。研究结果将有助于土壤修复以及定位和控制受污染的农田。
