Atmospheric Bulk Deposition of PCDD/Fs, PCBs, and PBDEs in the Vicinity of Steel Complex

Abstract

An IRA-743 resin bulk sampler was used to monitor long-term bulk deposition of polychlorinated dibenzo-p-dioxins and dibenzofuran (PCDD/F), polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) bulk deposition. Six consecutive sampling campaigns (January 2008？CMay 2009) were conducted at four sites around an iron and steel making plant in Pohang, South Korea to investigate spatial and seasonal variations of PCDD/F, PCB, and PBDE bulk deposition. The steel complex site showed the highest average deposition fluxes of 0.35, 74.00, 2.10, and 41.60 ng/m2/day for °4？C8 PCDD/F (Tetra-Octa), °tri？CdecaPCBs (Tri-DecaCBs), °12PCBs (dioxin-like PCBs), and °8PBDEs (8 PBDE congeners), respectively, indicating the steel complex is an important source of persistent organic compounds (POPs) in this study area. Furthermore, the prevailing winds were confirmed to influence the spatial distribution of PCDD/F deposition. There were apparent seasonal variations of the bulk deposition of PCDD/Fs at each site, and seasonal homologue patterns of PCDD/Fs were clearly observed in the steel complex. However, no clear seasonal variation of PCB and PBDE deposition was observed except at the steel complex site. According to passive air sampling in the study area, no significant seasonal change of ambient air concentrations of PCDD/Fs was observed. Therefore, it was concluded that the seasonal variations of deposition fluxes of PCDD/Fs probably resulted from temperature-dependent gas/particle partitioning i.e., increased amount of PCDD/Fs in the particles and thus more deposition during colder seasons. Precipitation and homologue patterns appeared to play important roles in the deposition distribution of PCBs and PBDEs in this study area. In addition, the contribution of DL PCBs to the total TEQ (Toxicity Equivalent Quantity) showed a seasonal variation at each site and was not negligible in the vicinity of steel complex.