ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    塔里木河下游垦区土壤重(类)金属地球化学特征及潜在生态风险评价

    Geochemical Characteristics and Potential Ecological Risk Assessment of Soil Heavy Metals in the Lower Tarim River Reclamation Area

    • 摘要: 为查明塔里木河下游垦区土壤重(类)金属地球化学特征及潜在生态风险,采集表层土壤样品125件,测定其As、Hg、Ni、Cr、Cu、Zn、Cd和Pb 8种元素含量和pH值大小,基于地统计学、内梅罗综合污染指数法(Nemerow comprehensive pollution index,Pn)和潜在生态风险指数法(Potential ecological risk index,RI)对土壤重(类)金属潜在生态风险进行评价,利用正定矩阵模型(Positive matrix factorization,PMF)对重(类)金属来源进行解析。结果表明:①研究区内所有重(类)金属元素的含量均值未超过国家农用地土壤污染风险管控筛查值,含量整体处于正常水平。②研究区RI指数的变化范围为50.75~179.07,生态风险轻微、中等、较强的样点分别占29.37%、63.63%和7%,说明研究区整体处于中等生态风险等级。③PMF模型结果表明,研究区土壤重(类)金属主要来自于自然因素(48.88%),其含量与地质背景密切相关;其次为农业生产(31.63%),大量化肥、农药的使用导致耕地区重(类)金属含量较高;煤炭燃烧(12.20%)和交通运输(7.29%)对重(类)金属元素累积也有一定的贡献。

       

      Abstract: To identify the geochemical characteristics and potential ecological risk of heavy metals in soils of the lower Tarim River reclamation area, 125 surface soil samples were collected and their As, Hg、Ni、Cr、Cu、Zn、Cd and Pb concentrations and pH values were determined. The potential ecological risk of soil heavy metals was evaluated based on geostatistics, Nemerow comprehensive pollution index(Pn)and Potential ecological risk index(RI), and the sources of heavy metals were analysed using Positive matrix factorization (PMF). The results show that:①The average values of all heavy (class) metal elements in the study area did not exceed the national screening values for soil pollution risk control on agricultural land, and the levels were generally at normal levels. ②The range of variation of the index in the study area was 50.75 to 179.07, with 29.37%, 63.63% and 7% of the sample points with slight, medium and strong ecological risk respectively, indicating that the study area as a whole was in the medium ecological risk class. ③The results of the PMF model show that the heavy (class) metals in the study area come mainly from natural factors (48.88%) and their content is closely related to the geological background; followed by agricultural production (31.63%), the use of large amounts of chemical fertilisers and pesticides leads to a high content of heavy (class) metals in the cultivated area; coal combustion (12.20%) and transportation (7.29%) also contribute to the accumulation of heavy (class) metal elements. Coal combustion (12.20%) and transportation (7.29%) also contribute to the accumulation of heavy (class) metals.

       

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