陕西潼关农田土壤及农作物重金属污染及潜在风险

对矿业活动频繁的陕西潼关农田土壤和主要农作物小麦和玉米中的Hg、Cd、Pb、Cu、Zn和As元素的污染现状进行了调查.结果表明,潼关农田土壤主要受到Hg、Cd、Pb的污染,超标率分别为89.8%,57.1%和12.2%,研究区83.6%的土壤已经受到了不同程度的重金属污染.小麦和玉米样品的调查表明,Hg、Cd、Pb是研究区农作物最主要的污染物,小麦和玉米中3种重金属的超标率分别为39.1%和44.4%,39.1%和33.3%,47.8%和33.3%.从潜在生态危害指数可以看出,样品具有轻微、中等、强和很强生态危害的比例分别为44.9%、38.8%、12.2%和4.1%,具有轻微的生态危害的农田土壤主要分布在研究区西北部和东部;具有中等的生态危害的农田土壤主要分布在研究区中部和南部;具有强生态危害和很强生态危害的农田土壤分布在南部.小麦和玉米中重金属含量与土壤中重金属含量的相关性分析表明,小麦和玉米中Hg的含量与土壤中Hg的含量显著相关.研究表明,加紧对陕西潼关重金属污染农田的治理刻不容缓.

Assessment of the heavy metal pollution and potential ecological hazardous in agricultural soils and crops of Tongguan,Shaanxi Province

Tongguan, Shaanxi Province was found to suffer the influence of mining activity. The contamination status of Hg, Cd, Pb, Cu, Zn and As in both farmland and main crops wheat and corn was investigated. 83.6% of farmland soils were polluted to different extent, mainly by Hg, Cd and Pb, which exceeded the standard by 89.8%, 57.1% and 12.2%, respectively. Crops were also mainly polluted by Hg, Cd and Pb, which exceeded the standard by 39.1%, 39.1% and 47.8% in wheat and 44.4%, 33.3% and 33.3% in corn, respectively. The soils with low, moderate, high and very high values of potential ecological risk index were 44.9%, 38.8%, 12.2% and 4.1%, respectively. The soils with low values of potential ecological risk index mainly occurred in northwest and east, the soils with moderate values of potential ecological risk index were mainly distributed in the middle and south and the soils with high and very high values of potential ecological risk index were primarily located in the south. Correlation analysis between metal concentration in farmland soils and crops showed a significant correlation between the Hg in wheat and corn and the Hg in soil. Overall, immediate action was needed to remediate the heavy metal pollution in the farmland of Tongguan.