Seasonal Variation and Gas/Particle Partitioning of PCBs in Air from Central Urban Area of an Industrial Base and Coastal City -Tianjin, China

Abstract

The 26 air samples were collected from Tianjin urban areas from July 2010 to May 2011 for the analysis of 86 PCB congeners to investigate the gas/particle partitioning of PCBs. The total PCBs concentration (in pg/m 3 ) ranged from 31.28 to 650.33 (mean: 273.77) and showed a significantly seasonal variation as summer > autumn > spring > winter. Gas PCBs accounted for 80.79% of total PCBs. The fraction of each gas PCB homolog increased with the decreasing chlorine atoms. The contribution of gas PCBs to total PCBs showed a strong seasonal variation with summer (94.07%) > autumn (78.91%) > spring (78.19%) > winter (56.02%). Tri-, tetra-and penta-PCBs were the predominantly homologs in Tianjin atmosphere. The natural logarithm of partial pressure of PCBs were well correlated with the inverse absolute environmental temperature (R = 0.79). The steep slope of -4933.64 obtained from Clausius-Clapeyron (C.C) plot indicated the influence of local PCBs sources. In generally, the C.C slopes and the surface-air exchange enthalpy (∆H SA ) for different PCB homologs increased with the increasing chlorine atoms. The fraction of particle bound PCBs were underestimated for PCBs with P L 0 > 10 -3.85 Pa and overestimated for PCB congeners with P L 0 < 10 -3.85 Pa by Junge-Pankow model. The logarithm of particle/gas partitioning coefficients (log K P ) of PCBs were well correlated with the logarithm of respective sub-cooled vapor pressures (log P L 0 ) (R = 0.72) and the octanol-air partition coefficient (log K OA ) (R = 0.77). The slopes for log K P against log P L 0 and log K OA plots were -0.44 and 0.48, deviated significantly from the expected -1 and +1 for the equilibrium state of gas/particle partitioning, possibly explained by the emission of PCBs and particles from the local industries and other sources. The TEQ concentrations (fg/m 3 ) for 12 dioxin-like PCB congeners ranged from 35.628 to 612.796 with the mean value as 144.878.

Characterization of PAHs and PCBs in Fly Ashes of Eighteen Coal-Fired Power Plants

“…The standard solutions of PCBs and organic solvents used in this study were same as Li et al (2015). The detailed sample analysis procedure was described in previous studies (Li et al, 2011(Li et al, , 2015.…”

“…The detailed sample analysis procedure was described in previous studies (Li et al, 2011(Li et al, , 2015. The 60 g of sample was Soxhlet extracted with acetone: n-hexane (v:v = 1:1) for 24 h, concentrated by rotary vacuum evaporation, purified by a silica gel column and re-concentrated to 0.5 ml under a gentle N 2 stream before analysis.…”

“…The toxic equivalency (TEQ) concentration was calculated for each dl-PCB through multiplying its concentration by its WHO 2005 toxic (Li et al, 2011(Li et al, , 2015. The sum of 11 dl-PCBs ranged from 2.23 ng g -1 for FA8 to 6.52 ng g -1 for FA5 with the mean value as 3.35 ng g -1 , which were in the range of 0.00-13.8 ng g -1 for dlPCBs in fly ashes from municipal solid waste incinerators (MSWI) in Korea reported by Shin and Chang (1999), higher than 1.65 ng g -1 for 15 large-scale MSWIs in China reported by Pan et al (2013) and 0.52-2.3 ng g -1 for 4 MSWIs in China reported by Wu et al (2016).…”

“…PCBs are a kind of classic POPs due to their high lipophilicity, toxicity and difficulty of degradation (Guo et al, 2014;Liu et al, 2014). Although CFPPs is a known PCBs emission sources (Jansson et al, 2011;Li et al, 2011Li et al, , 2015, the PCBs emission characteristics in CFAs from CFPPs has not been studied extensively as other POPs in China. The significant difference of PCB profiles existed among the flue gases, CFAs and Aroclor mixtures, possibly resulted from different formation mechanisms, so the systematically research on PCBs in CFAs is needed (Jansson et al, 2011).…”

Catalytic Decomposition of PCDD/Fs over Nano-TiO2 Based V2O5/CeO2 Catalyst at Low Temperature

“…However, dioxins and other aromatic compounds emission from incinerators are proved to be harmful for human health, and thus the extensive development of incinerators is rejected by society (Gao et al, 2009;Yan et al, 2011;Cheruiyot et al, 2015;Li et al, 2015;Tiwari et al, 2015). Dioxins, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), have been incorporated into the Annex C compounds of the Stockholm Convention (Stockholm Convention, 2006) due to their chemical properties of stability, lipophilicity and persistence.…”