中国城市公园灰尘的重金属空间分布特征及其影响因素

Spatial distribution characteristics and influencing factors of heavy metals in urban park dust in China

通过收集公开发表的中国城市公园灰尘重金属数据,分析公园灰尘中Cr、Cu、Zn、Pd、Ni和Cd等6种元素的空间分布特征及富集状况,并对其影响因素进行了探讨.结果表明,Cr、Cu、Zn、Cd等4种重金属含量的空间分布具有相似性,东部地区为高值区,东北地区和西北地区为低值区;Pb和Ni具有相似的空间分布特征,东部和中部地区为高值区,西北地区则为低值区.与各省份的土壤背景值对比发现,除Cr在武汉市和开封市、Zn在包头市、Ni在北京市、武汉市和焦作市无富集状况以外,在其他城市公园灰尘中均具有一定的富集水平,且Cu、Pb、Cd等3种重金属元素在各城市公园灰尘中的累积指数均大于1.社会经济发展指标与公园灰尘重金属的相关性分析表明,Pb与总人口呈显著正相关;Cu、Zn与原煤呈显著正相关;Pb、Ni与民用汽车拥有量呈显著正相关.Cu、Zn元素含量主要受燃煤能源等能源结构的影响,Pb元素含量主要受到人口和交通因素的控制,Ni元素含量主要受交通因素的影响;Cr、Cd来源较为复杂,可能是自然和人为的混合源.

The data published on heavy metal contents in urban park dust in China were collected to analyse the spatial distribution and enrichment of Cr,Cu,Zn,Pd,Ni,and Cd in this dust.In addition,the factors that influence the distribution and enrichment of heavy metals were investigated.The results showed that the spatial distribution of Cr,Cu,Zn,and Cd contents was similar,and the eastern region was the high-value region,whereas the northeast and northwest regions were the low-value regions.The spatial distribution characteristics of Pb and Ni were similar,with high values in the eastern and central regions and low values in the northwest regions.By comparing the soil background values of each province,we found that except for Cr in Wuhan and Kaifeng,Zn in Baotou,and Ni in Beijing,Wuhan,and Jiaozuo,dust of other city parks exhibits a certain concentration level.In all the city parks,the three heavy metal elements,namely Cu,Pb,Cd,exhibited a dust accumulation index of>1.The correlation analysis of social and economic development indicators and heavy metals in park dust showed that Pb was significantly positively correlated with the total population;Cu and Zn were positively correlated with raw coal;and Pb and Ni were significantly positively correlated with the occupancy of civil vehicles.Moreover,Cu and Zn contents were mainly affected by the energy structure such as coal burning energy,the Pb content was chiefly controlled by population and traffic factors,and the Ni content was principally affected by traffic factors.The sources of Cr and Cd may be both natural and artificial and thus are highly complex.