Atmospheric deposition fluxes and compositions of dioxin-like polychlorinated biphenyls in Guangzhou, China
广州市类二恶英-多氯联苯大气沉降通量和组成

Atmospheric deposition of dioxin-like polychlorinated biphenyls (DL-PCBs) was investigated at four locations in Guangzhou between November 2005 and March 2006. The average deposition flux of DL-PCBs was 223 pg·m-2·d-1, and the corresponding TEQ was 1.5 pg·m-2·d-1. The deposition fluxes of DL-PCBs in urban areas were 1.6 times as high as those in suburban areas. Similar congener profiles were observed for four sites with PCB118, PCB105 and PCB77 being the major congeners. The relative mass contribution to the total deposition fluxes of DL-PCBs was in the following order: PCB118 (mean 30%) > PCB105 (mean 18%) > PCB77 (mean 17%). The deposition fluxes of DL-PCBs in the wet season were higher than those in the dry season, indicating that wet precipitation significantly impacted the deposition fluxes of DL-PCBs. Some products containing PCBs and solid waste incinerators were possibly the main sources of DL-PCBs.