畜禽粪便农用区土壤-小麦系统中重金属污染及迁移

畜禽粪便农用导致农产品中重金属含量超标,通过生物链传递,最终会影响人体健康。以山东禹城典型畜禽粪便农用区为例,研究了不同畜禽粪便农用区土壤—小麦系统中重金属的污染及迁移累积情况。结果显示:某些区域存在着一定的重金属污染,鸡粪农用区、猪粪农用区污染较高,综合污染指数均值分别为0.83、0.78,都达到了警戒级,其中某些点的污染指数超过了1和2,达到了轻污染或中污染级;牛粪农用区污染较轻,综合污染指数为安全级。不同畜禽粪便农用区小麦中的Cr、Ni、Cd、As均存在不同程度超标情况,其中鸡粪农用区Cr的超标率达66.67%,Ni、Pb超标率都为16.67%;牛粪农用区小麦中Cr、Ni超标,Cr超标率达91.67%;猪粪农用区小麦中只有Cr超标,超标率为41.67%。研究区小麦显示出不同的重金属富集能力,小麦对Cd、Zn、Cu几种元素的富集情况较高,而对Pb、As的富集能力则较低。除Zn外,小麦茎叶对同一种重金属的富集能力要大于小麦的种子。

Heavy metal pollution and migration in soil-wheat system of different livestock manures agricultural areas

Application of livestock manure to farmland can result in heavy metal contents of agricultural products.Through the food chain,ultimately,heavy metals have effect on human health.In this study,three areas of application different livestock manure in Yucheng city, Shandong province were selected to explore the heavy metal pollution and migration in soil-wheat system.The results showed that there was heavy metal pollution in the study areas.In areas with application of chicken manure and pig manure,the average values of pollution index were 0.83 and 0.78,respectively,reaching alert levels.The average values at some points were more than 1 and 2,at light pollution or pollution levels.The areas with application of cow manure was less contaminated,with the pollution index being at the security level.There were different degrees of over standard of Cr,Ni,Cd and As in wheat of different agricultural areas with livestock manures.In the wheat of chicken manure agricultural areas,the exceeding standard rate of Cr was 66.67%,and those of Ni,Pb were both 16.67%.In cow manure agricultural areas,Cr and Ni exceeded the standard,and exceeding standard rate of Cr was 91.67%.In the wheat of pig manure agricultural areas, only Cr exceeded the standard,the exceeding standard rate of Cr was 41.67%.The wheat showed a different ability of heavy metal enrichment.The wheat could highly enrich Cd,Zn and Cu but lowly enrich Pb and As.In addition,the accumulation ability of the same heavy metal of wheat stems and leaves was greater than that of wheat seeds.