受污染场地土壤重金属化学形态组成特征

受污染场地中重金属总量反映了场地的污染程度;而其形态则能反映场地的生态风险。通过采集天津某受污染场地内外土壤样品,分析测试了其重金属含量及形态。结果显示:污染场地内土壤中重金属含量显著高于场地外,其中Cd的污染最为严重,处于地累计指数评价法的2级水平。通过对重金属的形态分析发现,受污染场地内重金属的离子交换态、酸可提取态比例要高于场地外;因此,对于受污染场地的修复技术选择,要充分考虑重金属形态。

Concentration and form characteristics of heavy metals in soil of contaminated site

The total amount of heavy metal in soil of contaminated sites reflects the degree of contamination of contaminated sites while its forms are able to reflect the ecological risks of contaminated sites. Through collecting the soil samples inside and outside the contaminated sites of Tianjin, the concentration and form characteristics of heavy metals were analyzed. The results indicated that the heavy metal contents in soil within contaminated sites were significantly higher than that without contaminated sites. Among them, Cd was the most serious pollution and the pollution class of geo-accumulation index assess was Class 2, which meant moderately polluted. Through analyzing the forms of heavy metals in soils within or without the contaminated sites, it was found that the proportion of ion exchange forms and acid extractable forms in soils within contaminated sites were higher than that without contaminated sites. Therefore, when selecting remediation technologies of contaminated sites, to fully consider the heavy metal form.