Risk Assessment of Potentially Toxic Elements Pollution from Mineral Processing Steps at Xikuangshan Antimony Plant, Hunan, China

Abstract

We evaluated the direct release to the environment of a number of potentially toxic elements (PTEs) from various processing nodes at Xikuangshan Antimony Mine in Hunan Province, China. Sampling wastewater, processing dust, and solid waste and characterizing PTE content (major elements Sb, As, Zn, and associated Hg, Pb, and Cd) from processing activities, we extrapolated findings to assess wider environmental significance using the pollution index and the potential ecological risk index. The Sb, As, and Zn in wastewater from the antimony benefication industry and a wider group of PTEs in the fine ore bin were significantly higher than their reference values. The content of Sb, As, and Zn in tailings were relatively high, with the average value being 2674, 1040, and 590 mg·kg−1, respectively. The content of PTEs in the surface soils surrounding the tailings was similar to that in tailings, and much higher than the background values. The results of the pollution index evaluation of the degree of pollution by PTEs showed that while dominated by Sb, some variation in order of significance was seen namely for: (1) The ore processing wastewater Sb > Pb > As > Zn > Hg > Cd, (2) in dust Sb > As > Cd > Pb > Hg > Zn, and (3) surface soil (near tailings) Sb > Hg > Cd > As > Zn > Pb. From the assessment of the potential ecological risk index, the levels were most significant at the three dust generation nodes and in the soil surrounding the tailings reservoir.

Implications of Soil Potentially Toxic Elements Contamination, Distribution and Health Risk at Hunan’s Xikuangshan Mine

“…The P i of Sb had a maximum value of each site. Sb pollution was the most serious element in soil, consistent with the finding of the wastewater, dust, and tailings produced from discharge points at the antimony mineral processing plant of XKS [14]. For all the metals at SXN and SXS, P i > 1, and it was also found SXN had the highest P Sb (902.57 ± 910.98, average ± standard deviation, hereafter the same), indicating an extensive Cr/Zn/Cd/Pb/As/Hg/Sb multi-pollution at SXN and SXS.…”

“…As the metal with the most potential risk, Sb posed the highest ecological risk in SXN, SZS, and SXS, reaching 6317.99, 5784.30, and 3979.18, respectively, followed by SYA (1403.32). The E Sb of soils surrounding the tailings reservoir in the north of XKS reached 10548.42, indicating very high ecological risk [14]. Based on the average RI values (Figure 4) of all seven PTEs, the analysis showed that, overall, sites were at very high ecological risk.…”

“…A majority of the investigated research about XKS focuses on Sb and As contamination of water, sediment, and crops and estimates the contamination generation by the mining and smelting waste water, indicating that mining activities at the XKS mine have disturbed the natural equilibrium [11][12][13]. Processing wastes in the Sb beneficiation steps at the XKS, contributing severe contamination in localized soil, then dispersing into the air and water and leading to migration in the food chain [14]. The related researchers have studied the distribution characteristics and ecological risk of Sb, As, Pb, and Cd in the smelting area, the road nearby ore, the mining area, and the ore tailing area samples of XKS, which indicate that the antimony mining area was seriously polluted [15].…”

Speciation Distribution and Influencing Factors of Heavy Metals in Rhizosphere Soil of Miscanthus Floridulus in the Tailing Reservoir Area of Dabaoshan Iron Polymetallic Mine in Northern Guangdong

“…The existing studies on the changes of the rhizosphere environment mostly focus on the changes of heavy metal content in rhizosphere soil solution and the changes of plants' effective state of heavy metals. More studies on the morphological changes of heavy metals in soil solid phase use rhizosphere bags, rhizosphere boxes, and other artificial rhizosphere environments [9,10]. This simulated rhizosphere environment is different from the growth environment of natural plants.…”

Gas, Water and Solid Waste Treatment Technology

“…Zhou et al [22] evaluated the direct release to the environment of a number of potentially toxic elements (PTEs) from various processing nodes at Xikuangshan Antimony Mine in Hunan Province, China. Sampling wastewater, processing dust, and solid waste and characterising PTE content (major elements Sb, As, Zn, and associated Hg, Pb, and Cd) from processing activities, we extrapolated findings to assess wider environmental significance using the pollution index and the potential ecological risk index.…”