西安城区大气有机氯农药的污染特征及来源分析

采用大流量主动采样器于2008年7—10月对西安城区大气进行采集,共获得颗粒态和气态样品24个,并对其中含有的17种有机氯农药(OCPs)进行了分析.结果表明:西安城区大气中ρ(α-硫丹)和ρ(β-硫丹)最高,分别为260.7和212.0pg m3,ρ(DDTs)(DDTs=o,p′-DDD+o,p′-DDT+o,p′-DDE+p,p′-DDD+p,p′-DDT+p,p′-DDE)为167.4pgm3,ρ(HCHs)(HCHs=α-HCH+β-HCH+γ-HCH)为199.3pgm3,ρ(trans-氯丹)和ρ(cis-氯丹)分别为104.0和97.3pgm3,ρ(六氯苯)为74.9pgm3,且都主要分布在气相中.来源分析表明,西安大气中DDTs受三氯杀螨醇的影响显著,而HCHs则主要来源于林丹的使用残留.α-HCH,HCB,p,p′-DDE及p,p′-DDT主要受污染物长距离传输影响,而γ-HCH,trans-氯丹,cis-氯丹,α-硫丹和β-硫丹主要受采样点周边地表挥发的影响.

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/m~3, 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 pg/m~3, 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.