【摘要】 通过田间采样及室内样品分析,对新乡市寺庄顶污灌区土壤和小麦子实中重金属污染特征进行了初步探讨。结果表明,土壤中Cr含量达标,Cd、Ni、Zn和Cu的含量超标,其平均含量分别为65.31、1196.64、2799.25和145.78mg.kg-1,是国家土壤环境二级标准的108.85、19.94、9.33和1.46倍;污染最严重的Cd主要以铁-锰氧化物结合态存在,所占比例平均为56.84%,Ni主要以铁-锰氧化物结合态和残渣态存在,所占比例平均为37.44%和39.55%,Zn主要以残渣态存在,所占比例平均为78.24%,Cu主要以有机结合态存在,所占比例平均为57.70%。小麦子实中Cd污染最严重,其平均含量为2.55mg.kg-1,是国家食品卫生标准的25.5倍,这主要是由于土壤中Cd总量严重超标且迁移能力最强的可交换态所占比例较高引起的,Ni、Cr和Zn含量分别是国家食品卫生标准的12.98、6.12和1.32倍,表明长期污水灌溉对寺庄顶灌区小麦的食品安全造成严重威胁,应引起足够的重视。更多还原

【Abstract】 A primary study was performed to investigate heavy metal pollution in soil and wheat grains in sewage-irrigated area in Sizhuangding,Xinxiang City.The results showed that the concentrations of Cd,Zn,Ni and Cu in soil were 65.31,1 196.64,2 799.25 and 145.78 mg.kg-1,and they were about 108.85、19.94、9.33 and 1.46 times of the value for target element in the National Environmental Quality Stan-dard for soils,respectively.The concentration of Cr in soil was less than the limited value.The chemical fractions of Cd,Zn,Ni and Cu in soil were also investigated.The results showed that Cd,Zn,Cu were dominated by iron-manganese oxides fraction,residual bound fraction and or-ganic fraction with the percentage of 56.84%,78.24% and 57.70%,respectively.But Ni was dominated by iron-manganese oxides fraction and residual bound fraction with the percentage of 37.44% and 39.55%.Moreover,the present study indicated that the contents of Cd,Ni,Cr and Zn in wheat grains were 25.5,12.98,6.12 and 1.32 times of value of the China National Hygienic Standards for Food.It showed that irrigation using wastewater resulted in the steadly increasing contents of heavy metals in soil which,in turn,contributed to elevated levels in grains.更多还原