A comprehensive investigation of hazardous elements contamination in mining and smelting-impacted soils and sediments.
A comprehensive investigation of hazardous elements contamination in mining and smelting-impacted soils and sediments.
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DOI：
10.1016/j.ecoenv.2020.110320
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发表时间：
2020-02
影响因子：
6.8
通讯作者：
Xiaolan Zhao;Bihong He;Hanyu Wu;G. Zheng;Xiangxian Ma;Jianjun Liang;Ping Li;Q. Fan
中科院分区：
文献类型：
--
作者：
Xiaolan Zhao;Bihong He;Hanyu Wu;G. Zheng;Xiangxian Ma;Jianjun Liang;Ping Li;Q. Fan
白银区大量的采矿和冶炼活动导致土壤和岸边沉积物中的有害元素(HES)受到严重污染。在这项研究中，分析了HES的浓度和化学形态，以评估这些HES在重点地区的环境风险。土壤中锌、铜、铅、镉的含量较2012年有明显下降，说明政府对污染土壤的治理在土壤修复中发挥了非常重要的作用。但锌、铜、铅仍超过背景值，研究区仍为Cd污染严重的地区。HES的空间分布表明，污染区域主要集中在采矿区、冶炼区和污灌区。顺序提取结果表明，污水灌区土壤中锌主要以残渣形态存在，而不稳定形态的比例有所增加。Cd的生物有效态含量极高(90%以上)，其生态风险远高于锌。在沉积物中，HES的浓度极高。然而，很少有研究调查研究区沉积物中HES的污染情况。随着气候和环境条件的变化，沉积物中的HES容易释放并影响地下水和灌溉水。此外，沉积物中锌和镉的有效态含量均在80%以上，表明沉积物具有较高的生物有效性和可移动性。与土壤中的HES污染相比，沉积物中的HES污染应受到更多的关注。
Extensive mining and smelting activities in the Baiyin district have resulted in a serious hazardous elements (HEs) contamination in the soils and overbank sediments. In this study, the concentrations and chemical fractions of HEs were analyzed to evaluate the environmental risks of these HEs in the focus areas. In soils, Zn, Cu, Pb, and Cd exhibited an obvious decline compared to the results in 2012, which confirmed that the treatments of the contaminated soils by the government have played a very important role in the remediation of the soils. However, Zn, Cu, and Pb still exceeded the background values, and the study areas were still extremely contaminated with Cd. The spatial distribution of HEs showed that the contaminated areas were mainly focused around the mining and smelting regions and the sewage irrigation regions. Sequential extraction showed that Zn was mainly present as a residue fraction, while the percentages of unstable fractions increased in the sewage irrigation region samples. As for Cd, the bioavailable fractions were extremely high (over 90%) and the ecological risk was much higher than Zn. In the case of the sediments, the concentrations of HEs were extremely high. However, few researches have investigated HEs contamination in the sediments from the study area. With changes in climate and environmental conditions, HEs in sediments will easily release and influence the groundwater and the irrigation water. Furthermore, the available fractions of Zn and Cd were over 80%, which suggests high bioavailability and mobility in sediments. HEs pollution in sediments should receive more attention compared to that in soils.