| Bai Yun Mountain in Guangzhou is famous for its beautiful natural scenery. There are 179 families, 553 genuses, 1002 categories of plants in Bai Yun Mountain, which accounts for 50% plants categories in Guangzhou. Located near the tropic of Cancer, Bai Yun Mountain has plenty of sunshine and rain. The plants here can grow all the year, which is beneficial for the formation of Semi-tropic Evergreen Broadleaved Forrest. Semi-tropic Evergreen Broadleaved Forrest is a regional forest type in Guangzhou and also the main botanic scenery in Bai Yun Mountain.Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds in the environment. Their contamination to environment can be transfer through atmosphere movement and atomosphere sedimentation. PAHs have strong biological accumulating property as a long standing lipophilic organic contaminant. The leaves of plants can accumulate PAHs which exist as gas and particles through dry or wet sedimentation and gas diffusion. Broadleaved plants have large surface area and the absorption by leaves is the main approach for the accumulation of lipophilic organic compounds in plants. Studies show that under the same exposure conditions large surface area and high lipid containing leaves have higher accumulating efficiency.16 PAHs from the leaves of 9 kind of broadleaved plants in Bai Yun mountain in Guangzhou were separated and analyzed quantitatively by GC-MS. The results are showed as follows.1. The overall concentration of the 16 PAHs from the leaves of the 9 broadleaved plants is 460.2～1286.9(average 751.2)ng/g. Pyr, Phe and Flu have relatively high concentration. The concentration of PAHs of different spieces are ranked as follows: Schima susperba (460.2 ng/g) < Symplocos lancifolia (503.3 ng/g) < Acacia mangiumm(584.5 ng/g)< Castanopsis fissa(606.8 ng/g)< Acacia auriculiformis(668.3 ng/g)< Ficus altissima(739.4 ng/g) < Ormosia pinnata(808.1 ng/g)< Celtis sinesis(1286.9 ng/g) < Schefflera octophylla(1303.5 ng/g)2. 3～4 ring compounds are the main components of the 16 PAHs. The ratio of 2, 3, 4, 5, 6 ring compounds are 12.5%, 23.3%, 43.3%, 15.9%, 5.0% respectively.3. The average content of PAHs from the broadleaved samples in this study and the average content of PAHs from the air samples collected by Xinhui Bi at old zone of Guangzhou were compared. The contents of 3, 4, 5, 6 ring compounds in PAHs of air sample are 34.33, 49.34, 22.24, 29,41 ng/m~3 respectively. And the contents of 3, 4, 5, 6 ring compounds in PAHs of plant leaves are 180.06, 334.73, 123.12, 38.88 ng/g. It is observed that the main components were the 3～4 ring compounds both in the air sample and the leaves sample. The contents of 5～6 ring compounds were small in both samples. These results demonstrated a good correlation in PAHs component between the air sample and the leaves sample.4. The ratio compare method of Molecular Mark was used to analyze the source of PAHs. Studies showed that PAHs in the broadleaved plants' leaves were originated from heat.In summary, the content and component_of PAHs from the leaves of broadleaved plants in Bai Yun Mountain in Guangzhou were studied. The effect of PAHs on the vegetation system in the region could be reflected by this study. The developed industry in Guangzhou has lead to high PAHs in the atmosphere, which is reflected by the content of PAHs in leaves of broadleaved plants in Bai Yun Mountain. The control and management of disposing PAHs to environment should be strengthened.
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