ISSN 1000-3665 CN 11-2202/P

    典型锑矿区地下水中锑污染年际变化特征和成因分析

    Characterization and causes of interannual variation of antimony contamination in groundwater of a typical antimony mining area

    • 摘要: 湘中锡矿山锑矿区重金属污染问题突出,近年来矿区大力实施废渣综合整治和生态修复工程,但地下水污染修复成效未知。通过2013—2022年连续10 a 采集的锡矿山锑矿区地下水样品,运用水化学分析、离子相关性分析、地统计学等方法,对地下水化学特征、锑污染年际变化特征、锑污染来源和途径进行了系统研究。结果显示:(1)锡矿山锑矿区地下水水化学类型主要为HCO3·SO4—Ca型,地下水水化学组分的形成过程受固废淋滤和盐岩溶解控制;(2)矿区泥盆系上统佘田桥组、锡矿山组以及矿区外围下石炭统3个灰岩裂隙含水层受到不同程度的锑污染,尤其是佘田桥组含水层,锑质量浓度均值达7.139 mg/L,受辉锑矿氧化影响显著,而锡矿山组、下石炭统含水层锑的来源主要受尾渣、废石等固体废弃物淋滤控制;(3)10 年间佘田桥组地下水锑质量浓度均值差异较大,2013—2015年,锑质量浓度均值为13.31 mg/L,逐年下降,2016—2018年锑质量浓度均值为7.28 mg/L,逐年略升,2019—2022年锑质量浓度均值为6.06 mg/L,整体呈下降趋势。分析表明矿区生态环境逐步转好,研究成果可为矿区生态修复工程实施成效评估、矿区重金属污染防治提供科学依据。

       

      Abstract: Heavy metal pollution is a prominent problem in the antimony mining area of Xikuangshan in central Hunan. In recent years, integrated waste remediation and ecological restoration projects have been vigorously implemented in mining areas, but the effectiveness of groundwater pollution remediation is unknown. Groundwater samples collected from the antimony mining area for 10 consecutive years from 2013 to 2022 are used to systematically study the chemical characteristics of groundwater, the inter-annual variation characteristics of antimony pollution, and the sources and pathways of antimony contamination by the hydrochemistry analysis, ion correlation analysis, and geostatistics. The results show that (1) the HCO3·SO4—Ca type is the main hydrochemical type of groundwater in Xikuangshan, and the formation process of chemical components in the groundwater is controlled by solid waste leaching and salt rock dissolution. (2) Three aquifers in the mining area are contaminated with antimony to different degrees, especially the Shetianqiao Formation aquifer, with an average antimony concentration of 7.139 mg/L, which is significantly affected by the oxidation of pyroxene. The sources of antimony in the Xikuangshan Formation and the Lower Carbonifer aquifer are mainly controlled by the leaching of solid waste such as tailings and waste rocks. (3) The average value of antimony mass concentration in groundwater in the Shetianqiao Formation aquifer varies greatly during the 10 years. From 2013 to 2015, the average value of antimony concentration was 13.31 mg/L, decreasing year by year. From 2016 to 2018, the average value of antimony concentration is 7.28 mg/L, increasing slightly year by year. From 2019 to 2022 the average value of antimony concentration is 6.06 mg/L, with an overall decreasing trend. Analysis shows that the ecological environment in the mining area is gradually improving. This study will provide a scientific basis for assessment of the effectiveness of the implementation of ecological restoration projects in mining areas, as well as the prevention and control of heavy metal pollution in mining areas.

       

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