渭河西安段沿岸土壤重金属化学形态及其潜在生态风险评价

CHEMICAL SPECIATION AND POTENTIAL ECOLOGICAL RISK ASSESSMENT OF HEAVY METALS IN NEAR-SHORE SOIL OF WEIHE RIVER( XI'AN SECTION)

分析渭河西安段4个断面近岸土壤中Cd、Pb和Cr元素的污染分布特征。采用Hakanson评价法分析3种重金属元素的潜在生态风险影响,并基于此对其赋存形态和迁移特征进行研究。结果表明:河段中Cd、Pb和Cr的平均值含量高于陕西背景值,其中Cd尤为突出。潜在生态风险评价表明,耿镇桥断面土壤采样点潜在风险处于"中等"程度。耿镇桥断面Cd元素形态分析结果表明,Cd元素主要赋存形态为可交换态(近56.59%),潜在迁移能力强,危害较大。

Horizontal distribution characteristics of three kinds of heavy metal elements, cadmium （Cd） ,lead （ Pb ） and chromium （Cr） in the near-shore soil in 4 sections of Weihe River in Xi＇an had been investigated. Potential ecological risk of heavy metals was evaluated using Hakanson risk assessment index. Their chemical speciation and migration characteristics were researched as well. Results indicated that the average concentration of Cd,Pb and Cr were higher than Shaanxi soil element background value, especially for Cd. Potential ecological risk assessment results showed that Gengzhen bridge section was in the middle rank and other sampling sites were in safety rank. The chemical speciation analysis of Cd element on Gengzhen Bridge section showed that Cd mainly existed in exchangeable form, which has stronger potential migration capability and higher harm.