蔬菜地土壤重金属污染与潜在生态风险研究

该研究选择4种不同的评价标准，采用Hakanson的潜在生态风险评价法对蔬菜地6种重金属污染潜在生态风险进行评价。评价结果表明，不同的评价标准，As、Cd、Pb、Cu和Zn单一元素的潜在生态危害系数差异不大，Eri值都小于40，生态危害程度均为Ⅰ级(轻度)，但不同评价标准之间，Hg元素的潜在生态风险系数差异较大，Eri值的波动幅度在19.59~114.4，生态危害程度为Ⅰ~Ⅳ级(轻度~很强)；从Eri值排序结果可以看出，两个采样区的Hg元素污染都排在第一位，其次是Cd元素污染。从潜在生态危害指数来看，4种不同的评价标准，两个采样区的RI值都小于150，As、Hg 、Cd、Pb、Cu和Zn 6种重金属的综合潜在危害程度均为轻度，但一号采样区的潜在生态危害风险高于二号采样区，建立蔬菜基地时应优先选择二号区。

Potential Ecological Risk of Heavy Metals in Vegetable Soils

Potential ecological risks of 6 heavy metals in vegetable soil were evaluated by using Hakanson’s potential ecological risk evaluation method, and 4 different sets of evaluation standards. The results showed that there didn’t exit significant difference among the evaluation standards in single-element potential ecological risk coefficient of As, Cd, Pb, Cu and Zn. The Eri value of As, Cd, Pb, Cu and Zn were all less than 40, posing little（Ⅰgrade） ecological hazard, but it was significant in the case of Hg, the Eri value of Hg was19.59 to 114.4, posing little(Ⅰ grade) to very strong (Ⅳ grade) ecological hazard. Sequencing of Eri value revealed that Hg pollution was on top of the list and followed by Cd pollution in the two sampling sites. In terms of potential ecological risk index, RI value of both sampling sites were less than 150, regardless of evaluation standards, suggesting that integrated potential ecological harzard of 6 heavy metals contents of As, Hg, Cd, Pb, Cu and Zn were slight. The potential ecological risk of heavy metals in Sampling Site No.1 was higher than in Sampling Site No. 2. Therefore, the latter should enjoy the priority of being chosen as vegetable production base.