| To select wheat varieties with low accumulation ability of heavy metals,edible safety and suitable to grow in Yellow and Huai River winter wheat zone,a field experiment was carried out to study the differences of Pb,As,Cr,Hg,Cd and Ni accumulation among 12 wheat varieties in typical farmlands in Fengxian in the ancient Yellow River old course. Then their potential health risks were assessed by Target Hazard Quentients(THQ). The results showed that the average contents of As,Cr,Cd and Ni in surface soils from 144 sampling points were about 0.14,0.20,1.32 and 0.20 times higher compared with national background values of soil elements,respectively. While the contents of Pb and Hg were lower than the corresponding values,and points of Pb content in soils beyond the standard were not found. But the contents of the six heavy metals in surface soils were lower than the secondary standard values of environmental quality standard for soils and the limit values of green food-environmental quality for production area. The content of the six heavy metals in grains of the twelve wheat varieties did not exceed the limit values of National Food Safety Standard. The differences of Pb,Ni,As and Cr accumulation were more apparent than other two elements,with Pb being the most obvious. Cluster analysis of the contents of the six heavy metals in grains showed that the twelve wheat varieties could be sorted into three groups. Baomai 20,Yannong 19,Bainong 207,Baomai 5,Ligao 6 and Qianmai 1were in the group of low accumulation varieties. Xinmai 28,Huaimai 20,Bainong AK 58 and Yunong 035 were in the group of midium accumulation varieties. Xumai 30 and Xumai 33 were in the group of high accumulation varieties. The average bioaccumulation factors of the six heavy metals for the twelve wheat varieties declined according to Hg,Cd,As,Pb,Ni and Cr. The different bioaccumulation degrees of heavy metals were found among the twelve wheat varieties. THQ value of individual heavy metal of each wheat variety and TTHQ value of the six heavy metals were below 1.0,implying that these heavy metals through consumption of the twelve wheat varieties had little potential health risk to the local residents.TTHQ value of Xumai 30,Yunong 035 and Xumai 33 ranged from 0.9 to 1.0,and the phenomenon must arouse enough attention. Based on synthesized evaluation,Baomai 2,Bainong 207,Baomai 5,Ligao 6 and Xinmai 288 with low accumulation ability of heavy metals were suitable to be planted in Yellow and Huai River winter wheat zone. |
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