Spatial Distribution And Source Apportionment Of Polybrominated Flame Retardants In The Atmosphere Of North China

Brominated flame retardants (BFRs) such as polybrominated diphenyl ethers(PBDEs) are important pollutants. They have drawn much attention for theirubiquity in the environment and potential adverse effects on human health, yet fewdata on ambient BFR levels have been available for North China, one of the mostdeveloped regions of the country. In this study, we investigated atmospheric levels,spatial distributions, and sources of BFRs based on gridded field observationscoupled with90-day passive air sampling in the aforementioned region.Among all analytes,13PBDE species (BDE-17,-28,-47,-49,-66,-99,-100,-153,-154,-183,-207,-208, and-209) and two substitutes (TBE and DBDPE) weredetected in most field samples. BDE-209and DBDPE were the two most abundantcongeners, with median concentrations of4.0and10.2ng/sample (average8.8and24.6ng/sample), respectively. These two chemicals constituted27.4±12.2%(range,17.2-35.2%) and65.5±13.7%(range,37.5-86.8%) of∑15BFRs, respectively. Themedian level of tri-through hepta-PBDEs (∑10PBDEs) was0.56ng/sample (average1.52ng/sample; or2.60and6.65pg/m3, respectively), which was lower than thoseobserved previously in mainland China and some other regions.Significant spatial variations were observed in the spatial distributions of BFRs.Model results revealed that non-point local emissions contributed nearly78%of∑10PBDEs observed in this study, while a point source of electronic-waste recyclingsite contributed nearly20%of the observed∑10PBDEs. In contrast, highconcentrations of BDE-209and DBDPE were observed, with median concentrationsof4.0and10.2ng/sample (average8.8and24.6ng/sample), respectively. Severalpoint sources located in the region around Laizhou Bay, Shandong Province, were the major sources, which contributed31%of BDE-209and70%of DBDPEobserved in this study, indicating that this manufacturing base was the mostimportant source region for atmospheric deca-BFRs in North China.7bromobenzene species (2,4,5-TrBT,1,2,3,5-TeBB,1,2,4,5-TeBB, PBT, PeBB,PBEB, and HBB) were detected in North China, and the median concentraion was5.33pg m-3(average10.5pg m-3).2,4,5-TrBT,1,2,3,5-TeBB, and1,2,4,5-TeBBwere reported for the frst time in ambient air with relatively high levels, and theycontributed60%of the total observed bromobenzenes in North China.Concentrations of PBT, PeBB, PBEB, and HBB were lower than those observedpreviously in Southern China and the Great Lake basin, indicating a relatively lightpollution in North China.Significant spatial variations of bromobenzenes were observed in this region.Up to14%of the atmospheric bromobenzenes observed in this study wascontributed by a significant point source of electronic-waste recycling site. Pointsources located in the region around Laizhou Bay, Shandong Province contributed14%of HBB and three newly detected bromobenzenes. Besides, non-point localemissions were the major source and accounted for nearly78%of atmosphericbromobenzenes in North China.In addition, we compared the modeling effect of Gaussian diffusion model andOrdinary kriging interpolation model for bromobenzenes. The latter one showed upa better fitting result; however, the Gaussian model was better in indicatingcontributions from specific point sources.