山东新泰废弃石灰岩矿区土壤重金属污染特征及来源解析

Pollution Characteristics and Source Apportionment of Heavy Metals in Soil of Abandoned Mines in Xintai City in Shandong Province

摘要:

土壤中重金属的富集是自然过程和人为活动共同作用的结果，土壤重金属来源解析及生态风险评价是开展土壤重金属污染防治的必要手段。为查明新泰市废弃石灰岩矿区土壤中重金属来源及其生态风险特征，系统的采集分析了新泰市15座典型废弃矿山65组表层土壤样品，对其pH和8种重金属含量进行统计分析。综合运用内梅罗污染指数（NPI）、地累积指数（Igeo）和潜在生态风险指数（Er）对研究区土壤重金属污染状况进行评价，利用相关性分析、聚类分析和主成分分析探究土壤重金属来源，采用绝对主成分得分多元线性回归（APCSMLR）受体模型定量计算各个污染源贡献率。结果显示，Cd、Hg、Cu、Zn、Ni的含量均值均超出当地土壤背景值；根据内梅罗污染指数可知，Cd、Hg、Cu、Zn为中度污染，As、Pb、Cr、Ni为轻度污染；根据地累积指数分析，土壤中Hg和Cd元素污染相对严重，为污染主要贡献因子；根据综合生态风险指数计算，处于中等生态风险点位占72%；相关性分析及主成分分析结果显示，As、Cr、Ni主要来源于母岩风化自然源，Cu、Zn主要来源于农用化肥、农药使用的农业源，Cd、Hg、Pb主要来源于汽车尾气、煤矿开采、燃煤等交通—工业混合源；APCSMLR模型揭示自然源、农业源、交通—工业混合源和未知源对研究区土壤重金属的贡献率依次为：28.77%、26.54%、28.33%和16.46%。

Abstract:

The enrichment of heavy metals in soil is the result of the interaction of natural processes and human activities. The source analysis and ecological risk assessment of heavy metals in soil are necessary means to carry out the prevention and control of heavy metal pollution in soil. In order to find out the sources and ecological risk characteristics of heavy metals in the soil of abandoned limestone mining areas in Xintai city, 65 groups of surface soil samples from 15 typical abandoned mines in Xintai city have been systematically collected and analyzed, and their pH values and contents of 8 heavy metals have been statistically analyzed. The Nemero comprehensive pollution index ( NPI ), geoaccumulation index ( Igeo ) and potential ecological risk index (Er) are used to evaluate the pollution status of soil heavy metals in the study area. Correlation analysis, cluster analysis and principal component analysis are used to explore the sources of soil heavy metals. The absolute principal component score-multiple linear regression ( APCS-MLR ) receptor model is used to quantitatively calculate the contribution rate of each pollution source. It is showed that the average contents of Cd, Hg, Cu, Zn and Ni can exceed the local soil background values. According to the Nemero comprehensive pollution index, Cd, Hg, Cu and Zn are moderately polluted, while As, Pb, Cr and Ni are lightly polluted. According to cumulative index analysis, the pollution of Hg and Cd in soil is relatively serious, which is the main contribution factor of pollution. According to comprehensive ecological risk index, the moderate ecological risk points can account for 72%. As showed by the results of correlation analysis and principal component analysis, As, Cr and Ni are mainly derived from the natural source of parent rock weathering, Cu and Zn are mainly derived from agricultural sources of agricultural fertilizer and pesticide use, Cd, Hg and Pb are mainly derived from traffic-industrial mixed sources, such as automobile exhaust, coal mining and coal combustion. According to APCS-MLR model, it is revealed that the contribution rates of natural sources, agricultural sources, traffic-industrial mixed sources and unknown sources to soil heavy metals in the study area are 28.77%, 26.54%, 28.33% and 16.46% respectively.