重庆地区主要作物重金属富集特征

Enrichment characteristics of heavy metals in main crops in Chongqing

采集了重庆地区6种主要作物(水稻、玉米、空心菜、红薯、土豆、南瓜)食用部分和对应根系土壤样品,分析了Pb、Cr、Zn、As、Hg、Cu、Ni、Cd8种重金属元素的含量,讨论了作物对重金属的富集水平及重金属的协同和排斥关系。结果表明,不同作物食用部分重金属的含量为籽粒类>根茎类>瓜果类,南瓜对8种重金属的富集能力远远低于其他物种,水稻富集水平较高;红薯和空心菜对Cr的富集、水稻对Cd的富集分别较为依赖于土壤中Cr、Cd的含量,而土豆对As元素的富集与土壤中该元素的浓度含量呈显著负相关关系;不同重金属在植物体内的富集协同和排斥关系均存在,但总体协同大于排斥,Zn和Cu、Cd和Ni、Cr和Ni多数呈协同关系,这种协同关系可以应用于重金属复合污染区域的植物修复。

The edible parts of six main crops （ Oryza sativa, Zea mays, lpomoea aquatica, Ipo- moea batatas, Solanum tuberosum, and Cucurbita moschata ） and corresponding root-zoning soil samples in Chongqing were collected to measure their Pb, Cr, Zn, As, Hg, Cu, Ni, and Cd contents, with the enrichment levels of and the synergistic/exclusion relationships between these metals in test crops were discussed. The heavy metals content in the edible parts of the crops was in the order of grain 〉 rootstalk 〉 melon and fruit, and the enrichment level of the metals was the highest in O. sativa and the lowest in C. moschata. The enrichment level of Cr in L batatas and L aquatica and of Cd in O. sativa depended on the soil Cr and Cd contents, respectively, while the enrichment level of As in S. tuberosum had a significant negative relationship with soil As content. Both the synergistic and exclusion relationships between the metals in test crops were observed, but in general, synergistic relationship was more existed than exclusion relationship. In most cases, the relationships between Zn and Cu, between Cd and Ni, and between Cr and Ni were synergistic, being available for the phytoremediation of the regions with multiple heavy metals pollution.