摘要
以上海中心城区为例,在分析地表灰尘重金属污染粒级效应基础上,研究重金属赋存形态及其生物有效性.结果表明,地表灰尘平均中值粒径为132μm,低于75μm粒径级别颗粒物占有最大的体积含量.重金属污染显示出明显的粒级效应,随着粒径降低,重金属含量呈现明显的增加趋势,150μm和75μm是主要级别,其中<75μm颗粒物污染物含量依次为Cr>Pb>Cd>Zn>Ni>Cu.对地表灰尘重金属赋存形态研究表明,Zn以碳酸盐态为主;Ni以残渣态为主;Pb主要为铁锰结合态存在,Cu和Cd则以有机态为主;Cr主要以残渣态存在.重金属活性形态比例依次为Zn>Pb>Ni>Cd>Cu>Cr.与国外城市相比,上海城市地表灰尘Zn、Pb和Ni生物活性比例较大,而Cu和Cd活性比例相对较低,Cr活性水平与其它城市相当,环境危害相对最小.
This paper presents data on size fractionation and bioavailability of heavy metal characteristics of urban surface dusts in Shanghai City. Result shows that medium size of surface dust is 132μm, 〈 75μm fraction has the highest volume percentage. Particle size distribution has the important influence on pollutant concentrations. With particle size decreasing, the heavy metal concentration increase, and the 〈 75μm fraction contains the highest levels of all of the heavy metals, and the order refers to Cr 〉 Pb 〉 Cd 〉 Zn 〉 Ni 〉 Cu. A five-step sequential extraction of roadside sediments showed that Zn is predominantly in the carbonate fraction; Pb is highest in the Fe/Mn oxide fraction; Cu and Cd are mainly distributed in the organic fraction; Cr and Ni are predominantly associated with residual fraction. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreases in the order of Zn 〉 Pb 〉 Ni 〉 Cd 〉 Cu 〉 Cr. Comparing with literature data abroad, the labile fraction of heavy metal bioavailability in Shanghai is higher for Zn, Pb and Ni, lower for Cu and Cd, and the same level for Cr.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2008年第12期3489-3495,共7页
Environmental Science
基金
国家自然科学基金重点项目(40730526)
国家自然科学基金项目(60670253)
关键词
城市地表灰尘
重金属
粒级效应
生物有效性
上海
urban surface dust
heavy metal
fractionation
bioavailability
Shanghai City
