| The study on the analysis and distribution of PAHs has never carried out in Guangxi. The research project was carried out in Liuzhou, the biggest industrial city in Guangxi and its distribution and source were discussed and analyzed.In order to research the distribution of PAHs in the atmospheric particles in Liuzhou, we at first made quality control and quality assurance on analytical process. Through the experiments of the recovery percentage of the labeling analytical standards add to the blanks, matrix, etc. it turned out that our recovery `percentage is satisfactory, the instrument detection limit is 4.21-12.95pg. and the method detection limit is 0.83-4.37μg/kg. The relative standard deviation of paralleling samples in the objective compounds account for all less than 17 per cent. Then we went taking some systematic collections in the respective places , such as. No.9 Middle School sample spot, Water Plant in Hexi, Environmental Monitoring Station in Sanzhong road as well as Fake-limbs Plant of Guangxi, and then extracted the samples with super-sonic wave's extraction, then contracted, purified, separated and contracted once again, at last blew it to the minority with nitrogen so as to conduct GC/MS analysis and obtained the respective percentage of sixteen preferentially controlling PAHs.Through the content analysis of PAHs, it turned out: ①the content in winter of particles or PAHs is much more than it in spring. However, the content of PAHs is neither proportional to the content of the particles, nor relative to it. The distribution of the PAHs has not any connection with the distribution of the particles. ②From January on, the content of PAHs in one day is on the declining trend. ③From winter to spring, the content of PAHs containing two benzene rings, such as naphthalene, acenaphthylene, acenaphthene, fluorene, etc is on the rising trend, while the contents of phenanthren, anthtacene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene containing 3～4 benzene rings, are on the declining side. From January to February, the contents of different PAHs areapproaching to average value. ④All the PAHs in Liuzhou City that their contents are high almost contain four benzene rings. ⑤ In winter, the content of respective sampling spot is as follows: Water Plant is more than the No. 9. Middle School, the No, 9 Middle School more than the Fake-limbs Plant and the Fake-limbs Plant more than Monitoring Station. In spring, the case is as follows: Water Plant is more than No.9 Middle School that is approximate to the Fake-limbs Plant, and the Monitoring Station. The contents of different PAHs in different spots reveal that there should be common sources of contamination to these spots.Through the analysis and discussion, we consider that the PAHs pollution mainly comes from the combustion of the coal, Because of higher temperature in spring than in winter, it makes the ratio of gas/solid of phenanthrene, anthtacene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene that contain 3~4 benzene rings, increase obviously . That makes the content of PAHS containing 3~4 benzene rings in particles decrease. Naphthalene, acenaphthene, acenaphthylene, fluorene that contain 2 benzene rings exist in form of gas principally, while benzo[ghi]perylene, dibenz[a,h]an thracene, indeno[1,2,3—cd]pyrene, etc. that contain 5~6 benzene rings mainly exist in the solid particles. The ratio of the gas/solid of all these compounds changes little with the temperature, which resulted in comparatively average distribution of the 16 kinds of PAHs.The discrepancy of the respective sampling spots stems from the climate and the locality. The north in Liuzhou is the central industry district. The large units consuming energy, such as Liuzhou Steel Plant, Liuzhou Power Plant, Liuzhou Chemical Fertilizer Plant. All locate in this district. Nevertheless, during the period of sampling, the principal wind orientation is the north-wind in the city which made the pol... |
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