Study On Organohalogens In Atmosphere In Shijingshan District, Beijing

Due to their carcinogenicity, mutagenicity and teratogenicity, as well as persistence and bioaccumulation, some organohalogens have gained utmost attention as contaminants of threat to human health. In this study, neutron activation analysis (NAA) and gas chromatography (GC) have been used to study organohalogens in air of gas and particles phase in Shijingshan District, Beijing, in order to get the distribution and sources of oganohalogens in the atmosphere, and support data to establish the related controlling steps and rules and to set up organohalogens models for further developments. It is analysis for organohalogens in Beijing atmosphere by NAA combined with GC, which detemined the extractable organohalogens bulk and species. Effects by related climate factor were discussed. It discovered clear correlations between EOCl, EOBr and EOI in air in Beijing, China.The method of NAA and GC for determination for organohalogens in gas and particle phase has been established. The NAA detection limits were 50ng, 8ng and 3.5ng for Cl, Br and I, respectively. The recoveries of OCPs and PCBs by GC were from63.0%～123.0% and from 60.5%~131.5%, which met the requirements of OCPs analysis by EPA (recovry range:100%±40%).The relative standard deviations (RSD) of them were from 7.3%～24.2% and from 4.4%～25.6%.The method of NAA and GC for determination of EOX and EPOX in air has been proved credible by experiments. The analysis results show that major fractions of EOX in air is an acid-liable or acid-soluble fraction during the sampling period, and the most of EOX is EOCl; The main source of EOBr(EOI) is the burning of heating fluel in Winter. The results might indicate that there are new inputs of HCH and DDT in air in Beijing. This implied that there are the additional usage of lindane and dicofol in recent years. The mean concentration of PCBs in gas phase is higher than it in particulate phase. C13-5-CBs are the most abundant isomers in polluted air. Because the products of PCBs in our country are mainly C13-CBs,C15-CBs,and most of them are used as transformer oil. It suggests that PCBs in air mainly originate from the leakage of transformer oil. In addition, the concentrations of EOX/EPOX in air are observably influenced by time, temperature and so on. So the resources of EOX/EPOX need to be studied furtherly.