北京市大气中多氯联苯的污染水平和分布特征

Levels and distribution of polychlorinated biphenyls in the atmosphere of Beijing

利用XAD树脂被动采样技术和同位素稀释高分辨气相色谱/高分辨质谱联用法(HRGC/HRMS)研究了2012年11月至2014年1月北京地区大气中多氯联苯(PCBs)的污染现状、区域分布特征及季节性变化规律.结果表明,北京大气中19种PCBs总浓度为8.42—45.2 pg·m-3(平均值23.1 pg·m-3),各采样点全年平均毒性当量范围为0.33—3.33 fg WHO-TEQ m-3(平均值1.85 fg WHO-TEQ m-3).PCB-11浓度范围为27.9—136pg·m-3,平均值为78.2 pg·m-3.大气中的PCBs以低氯代(2—5氯代)PCBs为主.季节变化规律呈现出夏/秋季节PCBs浓度高于冬/春季节的规律;区域分布特征呈现出人口密集的城区大于背景区、工业区大于城区的规律.

Air samples in Beijing were collected from November 2012 to January 2014 by XAD-resin passive sampling techniques to investigate the current contamination levels, regional distribution and seasonal variation of atmospheric polychlorinated biphenyls （PCBs）. Instrumental analysis was performed by high resolution gas chromatography/high resolution mass spectrometry （HRGC/ HRMS）. The results showed that the air concentration of PCBs were 8.42--45.2 pg. m-3（ average 23.1 pg. m-3 ）. The TEQ values were 0.33-3.33 fg WHO-TEQ m-3（ averagel. 85 fg WHO- TEQ m-3）. PCB-llconcentrations ranged from 27.9 to 136 pg. m-3 ,with an average of 78.2 pg-m-3 PCB profiles were dominated by low （2--5） chlorinated PCBs. The concentration of PCBs in summer/autumn was higher than those in winter/spring. The regional distribution of PCBs in Beijing air were in the order of industrial region〉densely populated urban areas〉the background area.