几种城市绿化树种叶片中铅砷铬镉汞元素的含量特征

2003年对昆明、思茅、丽江3个城市的16个绿化树种叶片中的铅、砷、铬、镉、汞5种重金属元素的含量进行了测定，并结合采集地的空气污染指数进行了相关分析。结果表明：麻栗坡含笑、山玉兰和杜英叶片中Pb的含量与空气污染指数间的相关性显著；石楠、云南拟单性木兰、山玉兰、冬樱花叶片中As的含量与空气污染指数间的相关性达显著或极显著水平；杜英、山玉兰、石楠、天竺桂、云南拟单性木兰叶片中Cr的含量与空气污染指数间的相关性均为显著和极显著；石楠、杜英、冬樱花叶片中Cd的含量与空气污染指数间有显著或极显著的正相关性；8个树种叶片中Hg的含量与污染指数间均没有显著的正相关性。而16个树种中，冬樱花叶片中5种重金属元素的总含量最大，为15．563mg／kg；总含量最低的树种是竹柏（0．692mg／kg）等，两者总含量的差异达14．871mg／kg。不同树种对环境中Pb、As、Cr、Cd、Hg等5种元素的吸收富集能力有较大的差异。16个树种叶片中Cd和Cr含量的相关系数为r0.05=0．582^＊，说明Cr与Cd之间有显著的互相促进作用；Cd与Hg元素含量的相关系数为r0.01=0．807^＊＊，也表明Cd与Hg间有十分显著的互相促进的作用。

Contents of Pb, As, Cr, Cd and Hg in Leaves of Sixteen Urban Tree Species

Contents of five heavy metal lead,arsenic,chromium,cadmium and mercury in leaves of 16 urban tree species planted at Kunming,Simao and Lijiang were measured in 2003.Correlation analysis between these content data and air pollution index from where the leaf specimens were collected was conducted.The results indicate that the Pb contents in the leaves of Michelia chartacea,Magnolia delavayi and Elaeocarpus decipiens are very significantly correlated with Air Pollution Index(API).There is significantly or very significantly correlation between API and As contents in the leaves of Photinia serrulata,Parakmeria yunnanensis,Magnolia delavayi and Cerasus cerasoides.The Cr contents in the leaves of Elaeocarpus decipiens,Magnolia delavayi,Photinia serrulata,Cinnamomum japonicum and Parakmeria yunnanensis are significantly or very significantly correlated with API.As far as Cd content is concerned,there is significant or very significant correlation between the Cd contents in the leaves of Photinia serrulata,Elaeocarpus decipiens and Cerasus cerasoides and API.There is no significant correlation between API and the heavy metal contents in other eight species.Among all the sixteen urban species tested,Cerasus cerasoides is the species with highest content of the five tested heavy metal elements,15.563 mg/kg,which is 14.871 mg/kg higher than that of Podocarpus nagi(0.692 mg/kg).Plant's ability of absorbing heavy metal elements varies a lot with species.It is also found that in the leaves of these 16 species,the content of Cd is correlated with the content of Cr(r_(0.05)=0.582~(*)),which implies the significant positive correlation between the content of these two elements.Besides,the content of Cd is correlated with the content of Hg(r_(0.05)= 0.807~(*)),which implies the very significant positive correlation between the content of these two elements.