我国城市街道灰尘中重金属的成分分析

收集了国内39个大中城市的3 720个城市街道灰尘重金属数据,通过描述性分析、评价分析、聚类分析和功能分异分析,初步确定了我国大中城市街道灰尘中重金属的成分及其污染程度。结果表明,我国城市街道灰尘中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的平均赋存量分别为17.82mg/kg、3.67 mg/kg、152.85 mg/kg、143.58 mg/kg、0.66 mg/kg、46.74mg/kg、220.88 mg/kg、602.30 mg/kg,且变化幅度较大,呈偏态分布。除As、Cr、Hg外,其余重金属均低于国外相应平均值。富集系数、Nemerrow指数、地质累积指数和潜在生态危害指数评价表明,污染最为严重的重金属是Cd、Hg、Pb。39个城市中,铜陵、广州、株洲、湘潭、惠州、韶关属于Cd-Hg-Pb-Zn-Cu极严重污染型,南京、上海、北京、芜湖、沈阳、香港、石家庄、杭州、合肥、乌鲁木齐等15个城市属于Cd极严重污染,成都、金华、镇江属于Pb-Zn-Cu强度污染型,其余15个城市的其他重金属为一般中度污染型。南方片区城市街道灰尘重金属污染整体比北方片区严重,中小城市的Cd、Hg、Cu、Zn等污染比特大城市严重,Pb、Cr则相反。城市街道灰尘重金属污染按功能区从高到低为工业区、居民区、商业区、风景区。

Heavy metal ingredient analysis in the dust of the Chinese urban areas

The present paper intends to provide a heavy metal ingredient analysis in the dust of the Chinese urban streets based on the 3 720 samples collected from 39 large and media-sized cities in China.The results of our synthetic analysis indicate that the average content of eight heavy metals, such as that of As,Cd,Cr,Cu,Hg,Ni,Pb,Zn in the dusts over the streets of the above mentioned cities are respectively 17.82 mg/kg,3.67 mg/kg,152.85 mg/kg,143.58 mg/kg,0.66 mg/kg,46.74 mg/kg,220.88 mg/kg,602.30 mg/kg.The primary analysis findings also reveal that the distribution of such metals are in great variety and in skewed manner.Except for those of As,Cr and Hg,the ingredients of other metals prove to be lower than those in similar-sized cities of other countries.However,the ingredients of Cd,Hg and Pb tend to be the most severe pollutants in accordance with the related concentration coefficients.As to the Nemerrow index,geoaccumulation index and the potential ecological risk index,it is possible to divide the 39 cities involved into four types,that is,those extremely heavily contaminated by Cd-Hg-Pb-Zn-Cu(such as Tongling,Guangzhou,Zhuzhou,Xiangtan,Huizhou,Shaoguan),those 15 cities severely contaminated by Cd(such as Nanjing,Shanghai,Beijing,Wuhu,Shenyang,Hong Kong,Shijiazhuang,Hangzhou,Hefei,Urumqi and so on),and those seriously contaminated with Pb-Zn-Cu(e.g.Chengdu,Jinhua,Zhenjiang) and the rest 15 cities medium contaminated with the rest heavy metals involved.Generally speaking,cities in China south are more severely contaminated with heavy metals than those in the north.In addition,biggest cities are less contaminated with Cd,Hg,Cu and Zn than small towns,whereas biggest cities suffer worse contamination of Pb and Cr than those in towns.Besides,according to the functional zones,the contamination extent can also be categorized in the following order: industrial district > residential area > shopping centre > scenic spots.