选择豫北山前平原大田蔬菜种植区地下水为研究对象,分枯水期(5月)和丰水期(10月)采集地下水样品,采用电感耦合等离子体质谱仪(ICP-MS)分析重金属含量,借助空间分布特征,并结合主成分分析方法,对地下水重金属进行源解析.结果表明:(1)研究区枯水期和丰水期浅层地下水pH值均值分别为7.26和7.15,电导率(EC值)均值分别为1200μS·cm^-1和1256μS·cm^-1,丰水期浅层地下水表现为较低的pH值和较高的EC值.(2)研究区枯水期和丰水期浅层地下水重金属含量均低于《地下水质量标准》Ⅲ类标准,枯水期浅层地下水重金属含量均值大小依次为Ni〉Zn〉V〉Cu〉Cr〉Co〉As〉Pb〉Cd,丰水期浅层地下水重金属含量均值大小依次为V〉Ni〉Zn〉Co〉Cu〉Cr〉Pb〉As〉Cd.除V、Co和Ni外,其余重金属含量均值在枯水期和丰水期差异不显著.(3)受人类活动影响的Pb、Zn和As等重金属的空间分析结果表明,区内浅层地下水重金属含量较大的区域主要分布在区内东南部以及丹河和沁河交汇处附近,这两个区域土地利用方式主要为蔬菜用地,显示化学肥料对地下水重金属的影响.(4)采用主成分分析方法,提取4个主成分,主成分1包括Cr、Pb、Cd和V,其来源一致,可能与施用磷肥有关等;主成分2包括Ni和Cu,显示成土母质以及复合肥等肥料的混合作用;主成分3包括Co,显示其来自成土母岩;主成分4包括As和Zn,显示锌肥以及有机肥等肥料使用的影响.
Shallow groundwater of vegetable fields in North Henan Province was sampled during dry and wet season,and the heavy metal concentrations in groundwater were determined by ICP-MS. Spatial distributions of heavy metals in groundwater and principle component analysis were used to analyze the sources of heavy metals. The results demonstrated that the mean pH values of the shallow groundwater during dry season and wet season were 7.26 and 7.15,and the mean EC values were 1200 μS·cm-1 and 1256 μS·cm-1 respectively. The groundwater during wet season had low mean pH values and high mean EC values. The heavy metal concentrations in shallow groundwater in the two seasons did not exceed the "Groundwater Quality Standard" Class Ⅲ standard. Mean heavy metal concentrations decreased in the order of Ni〉 Zn〉 V〉 Cu〉 Cr〉 Co〉 As〉 Pb〉 Cd in dry season,and V〉 Ni〉 Zn〉 Co〉 Cu〉 Cr〉 Pb〉 As〉 Cd in wet season,respectively. Except for V,Co and Ni, the mean concentrations of other heavy metals had no obvious differences between dry and wet seasons. (3)The spatial distributions of Pb,Zn and As of shallow groundwater in the two seasons demonstrated that groundwater with high heavy metal concentrations mainly distributed in the southeast and west part of studied area which were mainly covered by vegetable fields with high application of fertilizers.Four major components could be extracted through PCA analysis. The first component,including Cr,Pb,Cd and V,might derive from phosphate fertilizer use,and the second component including Ni and Cu may reflect sources from both parent soil and rock and compound fertilizer,and the third one was Co mainly derived from parent soil and rock,and the last one included As and Zn from Zn fertilizer and organic fertilizer.