城市树木铅含量调查

Investigation on Contents of Lead in Trees in Urban Area

目的了解城市树木铅含量特征。方法于2001年5月(春)、8月(夏)、10月(秋)和12月(冬)采集A市阴香、大叶紫薇和芒果叶片,并于2001年12月采集黄葛榕树皮、树枝、叶片,以原子吸收分光光度法测定样品铅含量。结果阴香、大叶紫薇、芒果叶片铅含量随暴露于空气时间的延长而增加,且成叶铅含量高于幼叶。黄葛榕不同器官铅含量顺序为树皮>污染叶片>树枝>清洁叶片,大气铅污染源均为机动车尾气,且车流量大的路段黄葛榕树皮、树枝、叶片的铅含量较高。结论树木可吸附大气中的铅,对空气有净化作用。

Objective To understand the distribution characteristics of the contents of lead in trees in urban area.Meth-ods The leaves of Cinnamomum Burmanii,Lagerstroemia speciosa and Mangifera indica L were sampled in May(spring),Aug(summer),Oct(autumn )and Dec(winter),2001respectively.The barks,branches,leaves of Ficus virens ait var sublancelo-lata were collected in Dec,2001.The lead contents of all samples were determined by atomic absorption spectrophotometry.Results The lead contents of leaves of C burmani ,L speciosa and M indica in creased with the prolongation of the period of ex-posure to air.The mature leaves of these three kinds of trees showed higher contents of lead compared with those of tender leaves.The lead contents of different organs of F sublanceolata showed the following orders:barks>polluted leaves>branches>cleaned leaves.Higher contents of lead in barks,branches and leaves were found in F Virens near the roads with higher traf-fic volume and a same air pollution source of automobil exhausts.Conclusion The trees could adsorb lead in air and purify the air.