• 关键词：珠三角  PCBs  空间分布  氯数分布  logK_p vs logP_L^o

• 基金项目：国家自然科学基金项目(No.40503011);中国科学院知识创新工程项目(No.KZCX22SW2414)

• 李春雷
• 复旦大学环境科学与工程系, 上海200433

• 郝永梅
• 上海市水产研究所, 上海200433

• 麦碧娴
• 中国科学院广州地球化学研究所, 有机地球化学国家重点实验室, 广州510640

• 盛国英
• 中国科学院广州地球化学研究所, 有机地球化学国家重点实验室, 广州510640

• 傅家谟
• 中国科学院广州地球化学研究所, 有机地球化学国家重点实验室, 广州510640

• 摘要：为了考察珠三角地区冬季大气中PCBs的空间分布,于2001年12月24日至2002年1月16日在广州的市区、郊区和背景区进行连续的空气样品采样.采用GC-MS-SIM模式进行PCBs分析.结果表明,空气中PCBs的总浓度按照距离市区从近到远的次序依次降低.市区PCBs平均浓度是郊区的1.61倍,是背景区的2.54倍.PCBs各单体化合物的浓度分布表现出明显的地区差异.低氯取代PCBs的市区浓度比郊区和背景区的浓度高出很多,而高氯取代PCBs的空间差异不明显.在不同氯数PCB浓度之和对PCBs总浓度的百分贡献率分布中,市区、郊区和背景区都表现为三氯和四氯取代PCBs的贡献最大,而且不同地区两者的贡献率之和非常接近.市区和郊区空气中三氯和四氯取代PCBs的贡献比较接近;而背景区空气中四氯取代PCBs的贡献高达52.79%,是三氯贡献的近2倍.郊区和背景区空气中五氯取代PCBs的平均贡献率分别是9.65%和10.87%.仅就颗粒相而言,其PCBs平均贡献率在市区、郊区和背景区表现出非常好的一致性.对市区、郊区和背景区空气中logK_p与logP_L^o进行回归分析,其斜率mr分别是-0.60、-0.42和-0.45,都明显地偏离空气中气/固分配的理想平衡状态.

• Abstract：To study the spatial distribution of atmospheric PCBs in winter Pearl River Delta, air samples were collected from 24/12/2001 to 16/1/2002 in urban, suburban and background of Guangzhou city. Atmospheric PCBs were analysed by GC-MS-SIMmode. The result indicated that the winter concentrations of atmospheric PCBs decreased in the order of urban, suburban and background. The average PCBs concentration in urban area was 1.61 times as that in suburban and 2.54 times as that in background. The homologue patterns of PCBconcentrations were geographically different among urban, suburban and background. The concentrations of lower chlorinated congeners in urban atmosphere were much higher than those in suburban and background atmosphere, while for the higher chlorinated congeners, the spatial difference was not significant. With respect to the spatial distribution of PCBhomologues, tri- and tetra-CBs were identified as the main components. The summed contributions of these two components were similar among the three areas, with values of 77.21%, 77.19%, and 81.10%. The percentages of tri- and tetra-CBs were similar in the urban and suburban atmosphere, while in the background atmosphere, the percentage of tetra-CBs was nearly two times as that of tri-CBs, with value of 52.79%. The average contributions of penta-CBs to the total atmospheric PCBs were similar between suburban and background area, with values of 9.65% and 10.87%. Taking only particulate PCBs into account, the percentages of penta-CBs were well consistent among urban, suburban and background area, with values of 15.20%, 16.23%, and 15.87%. The slopes of logK_p versus logP_L were -0.60, 0.42 and -0.45 for urban, suburban and background, respectively, which were larger (shallower) than the expected theoretical value of^-1.

• Key words：Pearl River Delta  polychlorinated biphenels (PCBs)  spatial distribution  homologue pattern  logK_p vs logP_L^o

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