基于生物监测法的北京空气质量空间分布特征

基于生物监测法，以北京城区为研究区域，采集了不同功能区和交通水平下的20个采样点的油松松针，采用ICP-AES测定了松针中的w(Pb)、w(Cd)、w(Cu)、w(Zn)、w(S)和w(Ca)，对北京城区空气质量空间分布特征及潜在生态风险进行了分析. 结果表明:较高的w(Pb)主要分布在北京西南部的工业区和人口密集居住区；位于老城的交通繁忙区和人口密集居住区及西南部工业区的w(Cu)均较高；较高的w(S)主要出现在北京城西南及东南部的工业区. 因子分析表明:污染物Pb、Zn、Cd和S主要来源于混合污染源(如工业排放、家用炉灶和汽车尾气)；Cu主要由人为活动过程(如金属加工)释放. 总的说来，松针中w(Pb)与w(S)高于植物生长的正常范围，对植物生长和人类健康构成了潜在威胁，而Cd、Cu和Zn的污染未呈现潜在生态风险. 

Analysis of Spatial Distribution of Air Quality in Beijing Based on Biomonitoring Method

To assess the air quality of Beijing,China,using a biomonitoring method,samples of Pinus tabulaeformis needles were collected from 20 sites with different functions and traffic levels.The concentrations of heavy metals(Pb,Cd,Cu and Zn),sulfur(S) and calcium(Ca) in the needle samples were determined by ICP-AES.The results showed that high Pb concentrations were observed in the southwestern industrial area and densely populated residential area.Heavy traffic and dense residential sites located in the old city area,together with the industrial area in the southwestern part of Beijing,showed high Cu contents.High S concentrations primarily existed in the industrial sites,which are located in the southwestern and southeastern districts of Beijing.Furthermore,Pb,Zn,Cd and S were mostly originated from mixed pollution sources of industrial emissions,home furnaces and vehicle exhaust.Cu was mainly originated from anthropogenic activities such as metallurgical processes.On average,Pb and S posed a potential threat to plant and human health,since their contents in the needles were far above the normal ranges for plant growth.However,Cd,Cu and Zn did not show potential ecological risk.