天津市中心城区绿地土壤重金属污染分布现状分析

Distribution and Present Situation Analysis of Heavy Metal Pollution in Green Space Soil of Tianjin Central Urban Areas

为了解天津市中心城区绿地土壤重金属污染情况,该文对天津市中心城区部分公园绿地、居住绿地、道路绿地与特殊绿地4种土壤利用类型中的重金属铅(Pb)、镉(Cd)、汞(Hg)、砷(As)、铬(Cr)含量以及土壤pH值进行了测定分析。结果表明,天津市中心城区城市绿地整体土壤质量良好,符合土壤质量筛选值标准;而鉴于不同的地域土壤特性,与天津市土壤背景值对比发现,Hg、Cd、Pb均超过土壤背景值。土壤污染评价结果表明,西沽公园为重度污染,且具有强生态风险。pH值与重金属含量及分布没有明显相关性。该文还分析了重金属在垂直空间上的分布,不同功能用地重金属的分布特征以及重金属来源,并结合分析结果提出了绿地土壤重金属污染治理的具体措施。

To understand the heavy metal pollution situation in green space soil of Tianjin central urban area,the heavy metal concentrations of lead(Pb),cadmium(Cd),mercury(Hg),arsenic(As),chromium(Cr)and pH values in the soil of 4 functional areas such as park green space,residential green space,road green space and special green space were analysed.The results show that the overall soil quality of green space in the central urban area of Tianjin is good and meets the standard of soil quality screening value.However,in view of soil characteristics in different functional areas,Hg,Cd and Pb exceeds the background values of soil by comparison with the background values of Tianjin.The results of soil pollution evaluation show that Xigu Park is heavily polluted with strong ecological risk.According to pH value analysis,there is no significant correlation between pH value and heavy metal content and distribution.The distribution of heavy metals in vertical space and different functional areas,as well as the sources of heavy metals are also compared and analysed,and specific control measurements of heavy metal pollution in green space soil are proposed based on the analysis results.