大连市农田土壤重金属污染特征分析

韩雪榕; 张洪轩; 谌启鹏; 白金剑

doi:10.13421/j.cnki.hjwsxzz.2026.04.005

大连市农田土壤重金属污染特征分析

Analysis of heavy metal pollution characteristics in farmland soils of Dalian, China

摘要

摘要:
目的了解大连市农田土壤重金属含量特征、分布、来源及生态风险, 为制定本地化防治措施提供科学依据。
方法 2024年采集大连市所有涉农区市县土壤样品54份, 采用石墨炉原子吸收分光光度法测定铅(Pb)和镉(Cd), 火焰原子吸收分光光度法测定铬(Cr), 原子荧光分光光度法测定汞(Hg), 电位法测定pH值; 利用GIS地统计法、单因子污染指数法、内梅罗综合污染指数法和单因子潜在生态风险指数法研究大连市农田土壤重金属污染特征和污染水平; 结合Spearman秩相关分析和聚类分析法解析大连市农田重金属来源。
结果土壤样本中重金属含量中位数依次为: Cr (55.821 mg/kg)＞Pb(8.123 mg/kg)＞Cd(0.112 mg/kg)＞Hg(0.021 mg/kg)。以算术平均数与风险筛选值, Cd和Cr的超标率分别为22.22%和5.56%, 但所有点位算术平均数均未超过管制值。空间上, Pb、Cr、Cd高值区集中于金普新区。污染评价显示, Cd为首要污染物, 其单因子污染指数(1.983)、内梅罗指数(金普新区77.78%点位为重度污染)和潜在生态风险指数(算术平均数59.475, 较高风险)均最高, Hg次之(中等风险)。来源解析表明Cd与Pb同源, Hg和Cr来源独立。
结论大连市农田土壤环境质量总体较好, Cd和Hg污染风险较高。

Abstract:
Objective To investigate the content characteristics, distribution, sources, and ecological risks of heavy metals in farmland soils of Dalian, China, and to provide a scientific basis for the formulation of localized control measures.
Methods In 2024, 54 soil samples were collected from all agricultural areas in the counties and districts of Dalian. Lead (Pb) and cadmium (Cd) were measured using graphite furnace atomic absorption spectrometry, chromium (Cr) was measured using flame atomic absorption spectrometry, mercury (Hg) was measured using atomic fluorescence spectrometry, and pH was measured using potentiometry. Geographic Information System (GIS) geostatistical method, single-factor pollution index, Nemero comprehensive pollution index, and single-factor potential ecological risk index were applied to study the heavy metal pollution characteristics and levels in Dalian farmland soils. Spearman correlation analysis and cluster analysis were used to explore the sources of heavy metals in Dalian farmland soils.
Results The median concentrations of soil heavy metals in soil samples were the following: Cr (55.821 mg/kg) > Pb (8.123 mg/kg) > Cd (0.112 mg/kg) > Hg (0.021 mg/kg). Compared with risk screening value using arithmetic mean values, the exceedance rates of Cd and Cr were 22.22% and 5.56%, respectively, but the arithmetic mean values at all sites did not exceed the regulatory limits. Spatially, high-value areas of Pb, Cr, and Cd were concentrated in Jinpu New Area. Pollution assessment showed that Cd was the primary pollutant, with the highest single-factor pollution index (1.983), Nemero index (77.78% of sites in Jinpu New Area were heavily polluted), and potential ecological risk index (arithmetic mean 59.475, indicating relatively high risk), followed by Hg (moderate risk). Source analysis revealed that Cd and Pb shared the same origin, whereas Hg and Cr had independent sources.
Conclusion The overall environmental quality of farmland soils in Dalian is relatively good, but Cd and Hg pose relatively high pollution risks.

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