为研究典型农田土壤重金属和微塑料污染状况和空间分布,选取河南省开封市某典型农田为研究区域,对土壤重金属(Cr、Ni、Cu、Zn、Cd、Pb)和微塑料含量进行测定,采用克里金插值法对研究区域土壤重金属和微塑料污染状况进行空间分析,并利用内梅罗(Nemerow)综合污染指数法和污染负荷指数法对研究区域农田土壤重金属和微塑料污染进行评价.结果表明:研究区域土壤中存在不同程度的重金属和微塑料污染,其重金属污染Nemerow指数为2.51,处于中度污染水平;重金属-微塑料复合污染Nemerow指数平均值为2.62,处于中度污染水平.污染负荷指数法表明,研究区土壤已开始受到重金属和微塑料的污染,其重金属污染负荷指数为1.32,处于轻度污染水平;重金属-微塑料复合污染综合污染负荷指数为1.26,处于轻度污染水平.此外,土壤Cr、Ni、Cu、Zn、Cd和Pb的含量均值分别为49.24,28.29,29.67,68.69,0.29,22.28 mg·kg-1,分别是河南省土壤元素背景值的0.92,1.14,1.39,1.06,3.22,1.55倍,这表明开封典型农田土壤中的Cd和Pb不仅受成土母质的影响,还受人为活动的影响;土壤微塑料平均丰度为694.35 n·kg-1,高于背景值1.45倍.同时,重金属和微塑料空间分布结果表明,研究区域南半部分土壤Cd、Ni和Cu这3种元素较高,应当是由灌渠污泥施肥所造成的;道路两侧土壤Pb、Zn和微塑料含量较高,以及机井附近土壤Cd、Zn和微塑料含量出现高值,可归因于人类活动干扰的结果.人类活动是土壤环境微塑料输入的主要途径,再加上开封冬冷夏热的气候条件,推断开封典型土壤中微塑料含量高于背景值的原因可能是农膜的使用.
In order to study the pollution status and spatial distribution of heavy metals and microplastics in typical farmland,a typical farmland in Kaifeng City,Henan Province was selected as the study area,and the contents of heavy metals(Cr,Ni,Cu,Zn,Cd,Pb)and microplastics in soil were measured.The spatial analysis of soil heavy metal and microplastic pollution in the study area was carried out by the kriging interpolation method,and the soil heavy metal and microplastic pollution in the study area was evaluated by the Nemerow index method and the pollution load index method.The evaluation results showed that there were different degrees of heavy metal and microplastic pollution in the soil in the study area,and the Nemerow index of heavy metal pollution was 2.51,which was at the moderate pollution level,and the average Nemerow index of heavy metal-microplastic composite pollution was 2.62,which was at the moderate pollution level.The pollution load index method showed that the soil in the study area had begun to be polluted by heavy metals and microplastics,and the heavy metal pollution load index was 1.32,which was at the light pollution level,and the comprehensive pollution load index of heavy metal-microplastic composite pollution in the study area was 1.26,which was at the light pollution level.In addition,the results showed that the mean values of soil Cr,Ni,Cu,Zn,Cd and Pb were 49.24,28.29,29.67,68.69,0.29 and 22.28 mg·kg-1,respectively,which were 0.92,1.14,1.39,1.06,3.22 and 1.55 times as high as the background values of soil elements in Henan Province.This results indicate that Cd and Pb in typical farmland soils in Kaifeng are not only affected by the parent material,but also by human activities.The average abundance of microplastics in the study area was 694.35 n·kg-1,1.45 times higher than the background value.At the same time,the spatial distribution results of heavy metals and microplastics showed that the three elements of Cd,Ni and Cu in the southern half of the study area were high,which should be caused by the fertilization of irrigation canal sludge.The high content of Pb,Zn and microplastics in the soil on both sides of the road,as well as the high content of Cd,Zn and microplastics in the soil near the machine well,may be the result of interference from human activities.Human activities are the main way of soil environment microplastic input,coupled with the cold winter and hot summer climate conditions of Kaifeng,it is inferred that the content of microplastics in the typical soil of Kaifeng is higher than the background value may be the use of agricultural film.