陕西省农用地和建设用地重金属污染评价与生态风险分析

Assessment of Heavy Metal Contamination and Ecological Risk in Agricultural and Construction Lands of Shaanxi Province

  • 摘要:
    目的 科学评估土壤重金属污染,为土壤污染的精准治理与风险管控提供依据。
    方法 通过文献提取2000 ~ 2024年陕西省农用地和建设用地的土壤重金属实测数据,整合有效样本点位653个,采用反距离权重插值法(IDW)分析镉(Cd)、铅(Pb)和铜(Cu)的空间分布格局,并结合单因子污染指数法、内梅罗综合指数法(NPI)和潜在生态风险指数法(RI)评估其污染程度与生态风险。
    结果 渭南市农用地为Cd、Pb、Cu复合污染核心区,Cd平均含量2.36 mg kg−1,超出陕西省背景值23.60倍;宝鸡市建设用地Pb污染显著,其平均含量329.70 mg kg−1,为背景值的15.40倍。农用地中延安市、西安市、宝鸡市、咸阳市、渭南市、安康市和商洛市内梅罗综合指数大于3,达重度污染水平,其中Cd的单因子污染指数平均值为1.52,是主要驱动因子;建设用地整体污染程度较轻,但宝鸡市因Pb污染导致内梅罗指数高达4.87。潜在生态风险评价表明,建设用地综合潜在生态风险指数为1061.18,属高风险等级,显著高于农用地的306.69,主要源于Cd的较高毒性及其在建设用地中含量超过背景值41.50倍。
    结论 陕西省污染分布格局呈渭南和宝鸡双核突出特征,其中高毒性Cd是生态风险的主导因子,且建设用地因Cd的极端富集呈现出远超农用地的生态风险。

     

    Abstract:
    Objective The aim was to assess heavy metal contamination in agricultural and construction lands, in order to provide a basis for precise pollution control and risk management.
    Method Measured data of heavy metals in agricultural and construction lands of Shaanxi Province from 2000 to 2024 were extracted from the literature, integrating 653 valid sampling sites. The spatial distribution patterns of cadmium (Cd), lead (Pb) and copper (Cu) were analyzed using inverse distance weighting (IDW). The contamination degree and ecological risk were evaluated by the single-factor pollution index, Nemerow pollution index (NPI) and potential ecological risk index (RI).
    Result The agricultural land in Weinan City was identified as the core area of combined Cd–Pb–Cu contamination, where the average Cd content (2.36 mg kg−1) exceeded the Shaanxi background value by 23.60 times. Significant Pb contamination was observed in the construction land of Baoji City, with an average content of 329.70 mg kg−1, 15.40 times of the background value. In agricultural land, the Nemerow pollution index (NPI) exceeded 3 in Yan’an, Xi’an, Baoji, Xianyang, Weinan, Ankang and Shangluo, indicating severe contamination. Cd was the main driving factor, with an average single-factor pollution index of 1.52. Although the construction land was generally less contaminated, the NPI in Baoji reached 4.87 due to Pb pollution. The comprehensive potential ecological risk index (RI) for construction land was 1061.18 (high risk), significantly higher than that for agricultural land (306.69), which was largely attributed to the high toxicity of Cd and its concentration in the construction land exceeding the background value by 41.50 times.
    Conclusion The contamination pattern in Shaanxi Province is characterized by two prominent cores in Weinan and Baoji. Highly toxic Cd is the dominant factor of ecological risk, and the construction land exhibits far greater ecological risk than agricultural land due to the extreme enrichment of Cd.

     

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