农灌区土壤重金属形态分布及潜在生态风险

在对关中盆地典型农灌区土壤柱状样品进行重金属含量和形态分析的基础上,采用Hakanson潜在生态风险指数法评价了灌区土壤中重金属的潜在生态危害程度.结果表明,关中盆地农灌区土壤中Cd和Pb含量超过陕西省黄土母质背景值,并在土壤剖面上,Cd、Pb和Cr含量总体呈现波动的增加趋势.Cd、Cr和Pb的优势结合态主要以残渣态为主,其次为铁锰氧化物结合态和有机质结合态；生物有效态含量为泾惠渠灌区＞交口灌区＞洛惠渠灌区.从重金属潜在生态危害程度来看,重金属的潜在生态危害大小顺序为Cd＞Pb ＞Cr,交口灌区和洛惠渠灌区重金属的生态危害程度为强度,所以进行前期治理和预防显得非常必要.

Speciation Characteristics and Potential Ecological Risk of Heavy Metals in Soil in Irrigation District

Based on the heavy metal content and chemical speciation analysis of soil column sample in typical agricultural irrigation areas of Guanzhong Basin,the potential ecological risk of the irrigation areas soil was evaluated using Hakanson potential ecological risk index.The results showed that Cd and Pb content in agricultural irrigation areas soil were more than Shaanxi Province soil background value.In the soil profile,the content of Cd,Pb and Cr show the fluctuation increasing trend,wholly.The mainly chemical speciation of Cd,Pb and Cr were residual,the secondly chemical speciation of Cd,Pb and Cr were bound to iron and manganese oxides and bound to organic matter.The content of bio-availability in different agricultural irrigation areas were Jinghuiqu irrigation district>Jiaokou irrigation district>Luohuiqu irrigation district.The potential ecological risk of heavy metals were Cd>Pb>Cr.The heavy metal potential ecological risk degree was strength in Jiaokou irrigation district and Luohuiqu irrigation district.So,the preliminary treatment and prevention about heavy metals is very necessary in agricultural irrigation areas.