矿区复垦土壤种植小麦的重金属安全性

为分析矿区充填复垦土壤种植农作物的生态安全性，以中国徐州市柳新矿区复垦场地为例，对照当地农田土壤，对充填场地种植小麦不同部位As、Cd、Cr、Cu、Hg、Pb、Zn 7种重金属元素含量进行检测，分析了Cd、Cr在成熟小麦不同器官中的分布、富集情况，并利用单项污染指数法和综合指数法对小麦籽粒进行了风险评价。结果表明，三场地中Cd 和Hg在未成熟苗中的含量小于成熟茎中的含量，Cr、Cu和Zn则与之相反，Pb和As的含量规律性不太明显；复垦场地小麦未成熟根的重金属含量都小于成熟根中的含量；比照地中除Cr 和Zn之外，其余元素在未成熟根中的含量均大于成熟根的含量；参照粮食污染限量标准，小麦籽粒中Cd和Cr含量均超标。风险评价显示三场地小麦籽粒中Cd、Cr单项污染指数达到轻度至重度水平，综合污染指数处于轻度污染至中度污染水平之间。该研究对矿区粮食安全的监控具有重要的实际应用价值。

Safety of heavy metals pollution for wheat planted in reclaimed mining soil

To keep the ecological safety of cultivated crops in reclaimed lands by filling mining wastes and fly ash into subsided lands, the paper took Liuxin mining area, Xuzhou in China as research area. The contents of heavy metals As, Hg, Pb, Cu, Cd, Cr, Zn in different parts of wheat planted in reclaimed soils and control soil were tested and compared. The distributions of Cd and Cr in different organs of mature wheat and enrichment coefficient of root were studied. Besides, the single index and comprehensive index methods were used to evaluate the risk of wheat grain. The results showed that Cd and Hg contents were lower in immature seedlings than in mature stems, Cr, Cu and Zn contents were higher in immature seedlings than in mature stems, while the content regularity of Pb and As were not too obvious. All heavy metals contents were lower in immature roots than in mature roots in reclaimed soils. With exception of Cr and Zn, all the other heavy metals contents were higher in immature roots than in mature roots in control soil. According to the food standard, Cr and Cd contents in wheat grain exceeded the standard. The risk assessment results showed the single pollution index of Cd and Cr of wheat grain reached middle to high pollution level, the comprehensive risk index of wheat grain was in the middle to moderate pollution level. The study has important practical value for grain safety monitoring in mining areas.