上海市大气环境中有机卤素污染物的来源及分布规律

采用中子活化分析和气相色谱分析方法，检测了上海嘉定区2004-12～2005-08期间大气颗粒物和降水样品，分析了可萃取有机卤素（EOX）、可萃取持久性有机卤素（EPOX）、有机氯农药(OCPs)和多氯联苯(PCBs)含量.不同粒径大气颗粒物（TSP、PM₁₀）和降水中EOX月均浓度分别为：1?425.37 ng·m^-3、552.78 ng·m^-3和815.7 ng·L^-1，EPOX月均浓度分别为：21.18 ng·m^-3、10.7 ng·m^-3和低于检测值，OCPs月均浓度分别为：64.4　pg·m^-3、31.00 　pg·m^-3和7.08 pg·L^-1.结果表明，EOCl含量占EOX的 80%～96％，即有机氯是大气环境中有机卤素污染物的主要成分，有机卤素污染物绝大部分是酸不稳定化合物，而且大多数有机卤素是未知结构化合物.发现细颗粒具有元素择优富集效应.大气颗粒物是有机氯农药和多氯联苯的主要载体，有机卤素吸附物以5～8氯取代数的高氯PCBs和DDT及其代谢物组分为主，而降水中则以3～5氯取代数的低氯PCBs和HCH组分为主.

Source and Distribution of Organohalogens in Atmosphere in Shanghai

Neutron activation analysis (NAA) and gas chromatography (GC) were used to determine organohalogens in air particles and precipitation in Jiading District, Shanghai, collected between December 2004 and August 2005. Analysis of extractable organohalogens (EOX), extractable persistent organohalogens (EPOX), organochlorine pesticides (OCPs) and polychlorinated diphenyls (PCBs) in atmosphere were presented. Monthly average concentration of EOX in air particles (TSP, PM10) and precipitation were 1425.37 ng x m(-3), 552.78 ng x m(-3), and 815.7 ng x L(-1) respectively, EPOX were 21.18 ng x m(-3), 0.7 ng x m(-3) and ND, OCPs were 64.4 pg x m(-3), 31.00 pg x m(-3) and 7.08 pg x L(-1). Analytical results showed that 80% - 96% of EOX was EOC1, which indicated organochlorine was the major component of organohalogens in atmospheric environment. Most organohalogens were acid-liable and unknown compounds. Correlativity between different size particles and organohalogens concentration implied that fine air particles has the effect of preference for absorbance of organohalogens especially for organobromine and organoiodine. Distribution of PCBs congeners in air particles and precipitation was preliminarily studied, which suggested that air particles were major carrier of OCPs and PCBs absorbed predominantly penta-, hexa-, hepta-, octa-PCBs, DDT and its metabolites, however precipitation contained mainly tri-, tetra-, penta-PCBs and HCH.