小麦富集重金属的品种差异及其潜在健康风险评价

为了筛选出适合黄淮冬麦区种植的具有重金属低累积潜力且食用安全的小麦品种,在黄河故道丰县境内选取代表性农田,采用田间小区试验,研究了12个小麦品种籽粒对Pb、As、Cr、Hg、Cd和Ni富集的差异,并用目标危害系数(THQ)法对其食用后的潜在健康风险进行了评价。结果表明,试验区144个采样点表层土壤中As、Cr、Cd和Ni的平均含量较中国土壤元素背景值分别超标0.14倍、0.20倍、1.32倍和0.20倍,Pb和Hg均低于背景值,仅Pb未见超标点位,但所测6种重金属的含量均低于《土壤环境质量标准》中的Ⅱ级标准值和《绿色食品产地环境质量》规定的土壤中污染物含量限值。供试的12个小麦品种籽粒中的6种被测重金属含量均符合国家食品安全标准限制值,但对Pb、Ni、As、Cr的吸收累积差异较Cd、Hg明显,以Pb最为明显。聚类分析可将12个品种划分为较低累积类群(保麦2号、烟农19、百农207、保麦5号、荔高6号和迁麦1号)、中等累积类群(新麦288、淮麦20、百农AK58和豫农035)和高累积类群(徐麦30和徐麦33)。12个小麦品种的籽粒对6种重金属的平均富集系数由大到小依次为Hg、Cd、As、Pb、Ni和Cr,富集程度在不同品种间差异程度不同。其THQ值和总危害系数(TTHQ)值均小于1.0,表明居民消费供试品种小麦籽粒无被测重金属引起的潜在健康风险。但徐麦30、豫农035和徐麦33籽粒中重金属的TTHQ值均介于0.9~1.0,对此应引起重视。综合评价,保麦2号、百农207、保麦5号、荔高6号和新麦288可作为黄淮冬麦区种植的重金属低累积小麦品种。

Difference of Heavy Metal Bioaccumulation among Wheat Varieties and Their Potential Health Risk Assessment

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.