Polychlorinated biphenyl residues in sandstorm depositions in Beijing, China.

Sandstorms, which distribute many particles, are a special atmospheric occurrence and are frequent in northern China. We conducted this study to determine, for the first time, the concentration of polychlorinated biphenyls (PCBs) in sandstorm depositions. We collected 13 samples from urban areas of Beijing, and we measured a total of 144 PCB congeners. Thirteen samples all contained PCB residues. The total PCB concentration ranged from 1.6 to 15.6ngg(-1) (median, 4.8ngg(-1), dry weight), with trichlorinated biphenyls as the predominant homologue (>50.4%). Furthermore, we observed increasing PCB contamination from northwest to east Beijing. We later explored possible factors affecting contamination of the sandstorm depositions, which revealed a significant correlation between SigmaPCBs and the minimum particle size of the sandstorm deposition samples. Principal-component analysis revealed that the major source of PCBs in Beijing may be potentially associated with the number-one commercial PCB through the long-range transmission. In previous results, PCBs were not a severe component of contamination in sandstorm depositions of Beijing. However, this study suggested that sandstorm deposition may be a potential source of exposure to PCBs for the residents of Beijing, China.