不同粒径空调灰尘中的多氯联苯分布特征

Distribution characteristics of polychlorinated biphenyls in size-specific dust from air conditioner filters

多氯联苯(polychlorinated biphenyls,PCBs)是一类典型持久性有机污染物,尽管已被禁止近50年,但是这类污染物仍然能在环境中检出.室内灰尘是PCBs人体暴露的重要来源之一.空调滤网灰尘主要是沉积的室内空气颗粒物,在一定程度上反映了室内污染状况.以餐厅和实验室空调滤网灰尘为研究对象,测定不同粒径空调滤网灰尘中PCBs的暴露水平,分析灰尘性质对PCBs浓度的影响.结果表明,PCBs总浓度在6.73～23.90 ng/g之间,餐厅空调滤网灰尘中的PCBs浓度高于实验室.灰尘样品与世界其他地区室内灰尘的污染水平相比处于较低水平.由于样品中主要为低氯代PCBs,因此工业品Aroclor1016,Aroclor1232或Aroclor1242可能是主要来源.PCBs浓度与灰尘平均粒径及有机质含量有显著的正相关关系,与灰尘比表面积、总孔容、平均孔径、N/C原子比以及H/C原子比呈显著负相关,说明灰尘性质本身对PCBs暴露有重要影响.

Polychlorinated biphenyls （PCBs） are a class of typical persistent organic pollutants. They are still detectable in the environmental though prohibited in the past 50 years. Indoor dust is an important source of human exposure to PCBs. Dust settled or adsorbed on air conditioner filters causes indoor particles, reflecting contamination of the indoor environment to some extent. In the present study, PCBs in dust of different sizes were collected from air conditioner filters in dining rooms and laboratories. The results show that the total amount of PCBs ranges from 6.73 to 23.90 ng/g dw. The PCB level in dining room dust is higher than that in laboratories. Compared with other regions worldwide, the present results are relatively low. Industrial products Aroclor1016, Aroclor1232, or Aroclor1242 may be main sources of PCBs because low chlorinated compounds dominate the totals. In addition, it has been found that significant correlation exists between the concentrations of PCBs and dust properties including particle sizes and organic contents. However, PCB concentrations are negatively correlated with surface area, total pore volume, average pore size, ratio of nitrogen to carbon （N/C）, and ratio of hydrogen to carbon（H/C） in the dust. The results indicate that the dust properties have great influence on the concentrations of PCBs.