陕西省某工业园区春季大气降尘重金属污染特征及评价

Characteristics and Assessment of Heavy Metal Pollution in Spring Atmospheric Dust of an Industrial Park in Shaanxi Province

为研究陕西省某工业园区春季大气降尘中重金属元素污染特征,于2013年3月21日-6月7日使用降尘缸被动采样方法收集大气降尘样品,并利用火焰原子吸收分光光度法测定样品中Cu、Pb、Zn、Cd、Ni、Cr等重金属元素的质量分数,运用ArcGIS 9.3研究其空间分布特征,并使用Igeo(地累积指数)法评价大气降尘重金属污染水平.结果表明:研究区大气降尘中w(Cu)、w(Pb)、w(Zn)、w(Cd)、w(Ni)、w(Cr)的平均值分别为131.1、2 630.5、4 449.3、65.5、21.7、79.5 mg/kg,分别为陕西省表层土壤元素背景值的6.1、122.9、64.1、696.8、0.8、1.3倍.工业园区重金属元素质量分数高值区集中分布在西北-东南一带,Pb、Zn、Cu、Cd等重金属质量分数高值区位于园区中部,临近冶炼厂,Ni、Cr等质量分数高值区位于火电厂附近;重金属元素(Cu、Pb、Zn、Cd、Ni和Cr)质量分数水平方向高值区分布在以冶炼厂为中心0~2 km范围内,并随与冶炼厂距离的增加而逐渐降低.重金属元素相关分析表明,Cu、Pb、Zn、Cd四种元素之间及Ni与Cr之间存在极显著相关关系.聚类分析结果显示,Pb-Zn-Cu-Cd为一类,Ni-Cr为一类;结合空间分布变化特征,初步判断工业园区Pb、Zn、Cu、Cd重金属污染主要受金属冶炼和交通运输影响,影响Ni和Cr主要因素为燃煤.Igeo评价结果表明,工业园区春季大气降尘中Cd达极强污染,Pb、Zn达强-极强污染,Cu为中度污染,Cr、Ni基本无污染.

In order to characterize and assess the heavy metal pollution in the atmospheric dust of an industrial park in Shaanxi in the spring,the atmospheric dust samples were collected using dust deposition cylinder from March 21st to June 7th,2013.The concentrations of Cu,Pb,Zn,Cd,Ni and Cr in the samples were measured using flam atomic absorption spectrophotometry.The spatial distribution characteristics of heavy metals were analyzed by the ArcGIS 9.3,and the contamination levels were assessed based on the geo-accumulation index.The results show that the average concentrations of Cu,Pb,Zn,Cd,Ni and Cr in atmospheric dust were 131.1,2630.5,4449.3,65.5,21.7 and 79.5 mg/kg,respectively,which were 6.1,122.9,64.1,696.8,0.8 and 1.3 times of the background value of Shaanxi topsoil,respectively.The heavy metals were concentrated in the northwest-southeast zone.Pb,Zn,Cu,Cd were mainly distributed in the center of the industrial park near a smelting plant,and Ni and Cr were mainly distributed in the north near a coal-fired power plant.The high concentrations of heavy metals were distributed horizontally within the range of 0-2 km centered on the smelting plant,and gradually decreased with the increase of the distance from the smelting plant.Correlation analysis of heavy metals showed that Cu,Pb,Zn and Cd were significantly correlated with each other,as well as between Ni and Cr.Cluster analysis showed that Pb,Zn,Cu and Cd fell into one category,Ni and Cr belonged to another category.Based on the spatial distribution variation characteristics,it was suggested that the pollution of Pb,Zn,Cu and Cd in industrial park was mainly affected by metal smelting and transportation,while the main influence factors of Ni and Cr were coal combustion.The geo-accumulation index showed that in the spring atmospheric dust,Cd reached extremely high pollution level,Pb and Zn reached strong to extremely high level,Cu level was moderate,and there was no Cr and Ni pollution.