Pollution Characterization and Source Apportionment of Organochlorine Pesticides in Air in Xi'an City

Air samples were collected by a high volume active air sampler from July to October,2008,in Xi'an City.Twenty-four total suspended particle(TSP) samples and gas phase air samples were obtained,and concentrations of 17 organochlorine pesticides(OCPs) were analyzed.Results showed that the average mass concentrations of α-endosulfan and β-endosulfan were 260.7 and 212.0 pg m3 ,respectively,higher than the other OCPs.Average mass concentrations of DDTs(o,p′-DDD + o,p′-DDT + o,p′-DDE + p,p′-DDD + p,p′-DDT + p,p′-DDE ), HCHs(α-HCH + β-HCH + γ-HCH ), trans-chlordane, cis-chlordane, and hexachlorobenzene were 167.4,199.3,104.0,97.3 and 74.9 pgxA3 ,respectively.All the OCPs were mainly detected in the gas phase.Source apportionment indicated that DDTs was significantly caused by the application of dicofol,and HCHs mainly came from the usage of lindane.α-HCH,HCB,p,p′-DDE and p,p′-DDT could be subjected to long range transport,while γ-HCH,trans-chlordane,cis-chlordane,α-endosulfan and β-endosulfan might be from emissions in the surrounding area.