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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