Abstract
Major sources of pollution during the antimony (Sb) mining and processing are mining waste rock, smelting waste, tailings dam, and underground tunnel wastewater. The aim of the present study was to assess magnitude of pollution from Sb mine by taking four types of samples: soil in the mining waste rock zone, soil in the smelting zone, soil in tailings zone, and soil in underground tunnel wastewater zone. Sixty soil samples from the four zones were taken for experimental work, and the contents and morphological characteristics of the six potentially toxic elements (PTEs) such as Sb, As, Hg, Pb, Cd, and Zn in the soil samples were measured by using a hydride generation atomic fluorescence spectrometer (AFS-9700). The results show that the soil of the mine area is seriously polluted. The average contents of Sb, As, Hg, Pb, Cd, and Zn in the soil reach 1267.20 mg·kg−1, 94.44 mg·kg−1, 1.46 mg·kg−1, 184.19 mg·kg−1, 8.54 mg·kg−1, and 1054.11 mg·kg−1, respectively. There exists good correlation between the PTEs in the soil, with Sb strongly positively correlated with As, Hg, Pb, and Zn. The intensity of pollution is highest in the antimony-smelting zone, where the potential ecological risk index is over 15,000, followed by the tailings zone and mining waste rock zone, with the underground tunnel wastewater zone being the lowest. Using sequential chemical extraction, the elements are associated with the residual fraction, followed by organic-sulfide fraction, and smaller portions in the Fe-Mn oxide, carbonate, and exchangeable fractions. There are great differences in the speciation content of different elements in different sampling zones. The study implicates that Sb-smelting zone is the potential source of PTEs and maximum metals are associated with residual phase, out of which significant portion is associated with mobile fraction or phase.
Highlights
Metal mining, mineral processing, and smelting have caused serious environmental pollution, which has attracted extensive attention from researchers [1,2,3]. e wastes produced during the process of mining, processing, and smelting occupy a large area, and release a large number of harmful elements under the effect of rain leaching, resulting in continuous environmental pollution [4,5,6,7]
Previous studies have shown that the exploitation and smelting of antimony result in very serious Sb pollution in the soils of the surrounding mining areas [20], and antimony smelting slag is an important source of Sb pollution in nearby farmland soils [21]; the content of elements such as Sb, As, and Pb is usually very low in uncontaminated soils, but increases by three orders of magnitude in soils contaminated by antimony mining [11, 22], and the concentration of Sb in soils contaminated by abandoned mines ranges from 585 to 3184 mg·kg− 1 [23]
Pollution occurs during the whole exploitation process, and each process presents different pollution characteristics; only a general study of potentially toxic element (PTE) pollution is not conducive to fully grasp the detail on the nature of information of heavy metal pollution. erefore, taking XKS Sb mine as an example, this study makes a systematical investigation of the potentially toxic elements (PTEs) pollution in the soil in different functional zones of the Sb mine, fully exposing its characteristics, aiming to provide theoretical support for soil pollution reduction and soil remediation
Summary
Mineral processing, and smelting have caused serious environmental pollution, which has attracted extensive attention from researchers [1,2,3]. e wastes produced during the process of mining, processing, and smelting occupy a large area, and release a large number of harmful elements under the effect of rain leaching, resulting in continuous environmental pollution [4,5,6,7]. E wastes produced during the process of mining, processing, and smelting occupy a large area, and release a large number of harmful elements under the effect of rain leaching, resulting in continuous environmental pollution [4,5,6,7]. Xikuangshan (XKS) Antimony Mine in Hunan Province is the only super-large antimony mine in the world It has been mined and smelted for nearly 120 years, and its annual average output of antimony accounts for 25% of the global total [8]. Up to Journal of Analytical Methods in Chemistry the researches are mainly focused on the leaching, migration, and transformation of metals in solid waste of mineral resources [17,18,19], and there are few studies on the characteristics of metal pollution in different functional mining zones. Pollution occurs during the whole exploitation process (mining, mineral processing, and smelting), and each process presents different pollution characteristics; only a general study of potentially toxic element (PTE) pollution is not conducive to fully grasp the detail on the nature of information of heavy metal pollution. erefore, taking XKS Sb mine as an example, this study makes a systematical investigation of the PTE pollution in the soil in different functional zones of the Sb mine, fully exposing its characteristics, aiming to provide theoretical support for soil pollution reduction and soil remediation
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