污灌区土壤—小麦系统重金属污染、迁移和积累——以开封市化肥河污灌区为例

Polluting, transferring and accumulating of heavy metals in soil-wheat system in sewage irrigation region: a case study in Huafei River in Kaifeng, Guangdong

以开封市化肥河污灌区为例,研究了土壤-小麦系统重金属(Cd、Pb、Cr、Cu、Zn、Ni和As)污染、迁移和积累规律。结果表明,该区土壤重金属污染较为严重,所有样点的综合污染指数均大于1,其中Cd和As污染最为严重,其平均质量分数远远超出了土壤环境二级标准值。在该区土壤上种植的小麦也表现出一定程度的重金属累积,但其茎叶和种子重金属质量分数差别较大;在所有种子样品中,Zn质量分数都未超标,As、Cr和Pb质量分数部分到达了较高的残留水平,Cd质量分数则远远超出了国家食品限量卫生标准。依据重金属迁移累积率(?i),小麦对As和Cr的吸收能力较低,而对Ni和Cd的吸收能力较高;在所有小麦样品中,除Cu外,茎叶对同一重金属的平均富集能力均大于种子。

Thirteen paired samples both of soils and wheat grown in the sewage irrigation region of Huafei River in Kaifeng, Guangdong, were analyzed for Cu, Zn, Pb, Cr, Cd, Ni and As with AAS. Results indicate that soil pollution in the sewage irrigation region is very serious, and synthetic pollution index of all samples is more than 1. Cd and As were the most serious among the seven elements, and their content in soil are far beyond grade II of the national standard of soil quality in China. For all wheat seed samples, the contents of Zn is below, As, Cr and Pb are partly beyond, and Cd is beyond the national hygienic limits for foods in China.