云南省某煤矿开采遗址周边农用地土壤重金属污染评价及源解析研究

    Pollution Assessment and Source Identification of Heavy Metals in Farmland Soils around a Coal Mine Area in Yunnan Province

    • 摘要: 为开展某煤矿开采遗址周边农田土壤重金属污染源识别, 对土壤、大气降尘、灌溉水、农业化肥和煤矸石样品进行采集分析工作, 综合分析重金属污染因子、空间分布和外源介质, 结合重金属同源性分析、剖面分析、主成分分析和正定矩阵因子分析, 摸清调查区域土壤重金属污染情况以及污染源清单和贡献率。结果表明: (1)91.00%的土壤样品存在重金属污染情况, 土壤Cd、Cu、Cr、Ni、Zn、Pb和As含量超风险筛选值点位率分别为86.00%、15.00%、14.00%、19.00%、12.00%、6.00%和19.00%;土壤Cd、Zn、Pb和As含量超风险管制值点位率分别为23.00%、2.00%、2.00%和3.00%;(2)根据污染源解析结果, 土壤重金属主要来自于3种源。其中, 土壤本底贡献率为64.20%, 对Cu、Cr和Ni的贡献率较高, 分别为83.00%、90.80%和89.40%;煤矿区活动贡献率为23.10%, 对Cd的贡献率最高, 达93.70%;农用化肥施用贡献率为12.60%, 对As的贡献率最高, 为93.90%。研究结果可为同类型区域土壤重金属调查评价与污染源定量解析工作提供参考, 为掌握煤矿遗址周边农田重金属污染水平、采取有效断源措施和开展农田安全利用措施提供数据支撑。

       

      Abstract: The research area was located in one of the 100 priority coal mine counties in China. The area is an epitome of China's coal development, and thus is typical and representative. Samples from the soil, dust-fall, agrochemical and coal residue were collected, so as to analyse the soil contamination and the inventory and contribution of main pollutants around the coal mining site. The pollution factor, spatial distribution, and environmental medium of the heavy metals were comprehensively analysed, and statistical methods including homology analysis, profile analysis, principal component analysis, and positive matrix factorization, were combined to investigate the soil contamination and the inventory and contribution of main pollutants. Results show that: (1) 91.00% of samples were contaminated by heavy metals. The rate of soil Cd, Cu, Cr, Ni, Zn, Pb, and As exceeded risk screening values for soil contamination of agricultural land were 86.0%, 15.00%, 14.00%, 19.00%, 12.00%, 6.00%, and 19.00%, respectively. The rate of soil Cd, Zn, Pb and As exceeded risk intervention values for soil contamination of agricultural land were 23.00%, 2.00%, 2.00%, and 3.00%, respectively. (2) Based on the results of pollution source analysis, the heavy metal contamination in the area mainly came from three sources, i. e., soil background, coal mining production, and fertilizer application, which account for 64.20%, 23.10%, and 12.60% of the contamination, respectively. Specifically, the soil background has the highest contribution to Cu, Cr, and Ni, and the corresponding contribution rate was 83.00%, 90.80% and 89.40%, respectively. Coal mining production and fertilizer application have the highest contribution to Cd and As separately, and the corresponding contribution rate were 93.70% and 93.90%. The results could be a reference for heavy metal evaluation and pollution resources quantitative analysis of similar areas. Meanwhile, the study may provide data support for investigating the heavy metal pollution status around coal mine, cutting off the pollution sources, and taking effective measures for farmland safe utilization.

       

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