[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.