北京市三环沿线油松叶片重金属的累积特征、季节变化和来源解析

Accumulation,Seasonal Variations and Source Apportionments of Heavy Metal in Pinus tabulaeformis Needles of Beijing,China

城市绿化植物松树能够净化城市空气和土壤重金属污染,常被作为监测城市环境质量的指示植物。分别在2009年6月、2009年9月、2009年12月和2010年3月在北京市三环沿线采集油松(Pinus tabulaeformis)松针样品,进行重金属分析,并采用主成分分析对重金属的来源进行解析。结果发现,三环地区油松样品中存在重金属Pb、Cd和Hg污染,且具明显季节变化,冬季污染最严重。源解析结果表明冬季和秋季时,植物中重金属污染源主要为土壤源、交通源和燃烧源,其源贡献率约占40%、20%和20%。春季和夏季时,植物中重金属污染源主要为土壤源和交通源,其源贡献率约占40%和20%。

Deciduous trees could take up airborne metallic particulates and soil metals and accumulate them in their leaves.Therefore,the leaves of deciduous trees could be considered as a useful tool to decipher metal contaminations in mega cities.The concentrations of Cd、Cr、Hg、Zn、Cu and Pb in the Pinus tabulaeformis needle samples around the Three Ring Road in Beijing were collected in July,September,December 2009 and March 2010;respectively and measured by inductively coupled plasma mass spectrometry（ICP-MS）.The source apportionments of heavy metal in Pinus tabulaeformis needles were analyzed by principal component analysis（PCA） method.The metal elements in needle samples have shown different seasonal variations.Concentrations of Cd、Cr、Hg、Zn、Cu and Pb in samples collected in winter were significantly higher than other seasons,furthermore,Pb、Cd and Hg contaminations have existed in collected samples.The metal sources identified by PCA with needle samples indicated that the variances of metal element in autumn and winter were mainly influence by soil factor（accounted for40%）,traffic factor（accounted for 20%） and combustion factor（accounted for 20%）,respectively,whereas,the variances of metal element in spring and summer were mainly influence by soil factor（accounted for 40%） and traffic factor（accounted for 20%）,respectively.