四川省建设用地污染地块土壤污染特征

Study on soil contamination characteristics of contaminated construction land sites in Sichuan Province

  • 摘要: 为支撑四川省建设用地污染地块再开发安全利用,对四川省2017—2023年完成土壤污染状况调查的1 075个建设用地关闭搬迁地块土壤污染特征开展地块和行业层面统计分析。采用污染负荷指数法与系统聚类法,从污染地块占比、单位面积污染量与综合超标倍数表征风险,同时统计分析污染类型、典型污染物、超标空间分布及成因。结果表明:污染地块数量居前三的行业分别为铅锌冶炼、铅锌矿采选和铁矿采选;金属表面处理及热处理加工、炼焦、铅锌冶炼等行业污染物种类大于10个且土壤污染风险较高;污染类型以无机污染为主,砷、铅、六价铬为高频污染物(出现频率大于30%);污染地块超标空间主要分布于物料堆存区、生产区、污水处理区等。研究揭示了四川省建设用地污染地块“行业-污染物-分布区域-来源”的风险耦合特征,建议将金属表面处理及热处理加工、铅锌和铁合金冶炼等行业企业,砷、铅、六价铬等污染物,企业物料堆存区、生产区、污水处理区等重点区域纳入重点排查和监管清单,并对不同行业建设用地污染地块采取差异化管理模式,以提高管理资源分配和建设用地污染地块再开发利用效率。

     

    Abstract: To support the safe utilization of contaminated construction land for redevelopment in Sichuan Province, this study conducted statistical analysis on the soil pollution characteristics of 1 075 closed and relocated construction land sites that completed soil pollution status surveys from 2017 to 2023 at the site and industry levels. The pollution load index (PLI) and systematic clustering method were adopted to characterize the risk based on the proportion of contaminated sites, the amount of pollution per unit area, and the comprehensive exceedance multiple. Meanwhile, the types of pollution, typical pollutants, the spatial distribution of exceedance and causes of pollution were statistically analyzed. The results showed that the top three industries in terms of the number of contaminated sites were Pb/Zn smelting, Pb/Zn mining, and Fe ore mining. Industries such as metal surface treatment and heat treatment processing, coking, and Pb/Zn smelting had more than 10 types of pollutants and a relatively high risk of soil pollution. The pollution types were mainly inorganic pollution, with As, Pb and Cr6+ being high-frequency pollutants (occurrence frequency greater than 30%).The areas with excessive pollution in contaminated sites were mainly distributed in material storage areas, production areas, sewage treatment areas, etc. This study reveals the risk coupling characteristics of "industry-pollutant-distribution area-source" in contaminated construction land plots in Sichuan Province. It is suggested that enterprises in industries such as metal surface treatment and heat treatment processing, Pb/Zn and ferroalloy smelting, As, Pb, Cr6+ and other pollutants, as well as key areas such as material storage areas, production areas and sewage treatment areas of enterprises be included in the list of key investigations and supervision, while adopting differentiated management models for contaminated construction land plots in different industries to optimize resource allocation and enhance the redevelopment and utilization of contaminated construction land sites.

     

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