Polychlorinated diebenzo-p-dioxins(PCDDs),polychlorinated diebenzofurans(PCDFs),polychlorinated biphenyls(PCBs) and polybrominated diphenyl ethers(PBDEs) were monitored in the ambient air of Taizhou,an E-waste dismant...Polychlorinated diebenzo-p-dioxins(PCDDs),polychlorinated diebenzofurans(PCDFs),polychlorinated biphenyls(PCBs) and polybrominated diphenyl ethers(PBDEs) were monitored in the ambient air of Taizhou,an E-waste dismantling area of southeast China to evaluate their concentrations,profiles and gas-particle partitioning.The ΣPCDD/Fs concentrations ranged from 2.91 to 50.6 pg/m3,with an average of 14.3 pg/m3.The I-TEQs for PCDD/Fs were in the range of 0.20-3.45 pg/m3,with an average of 1.10 pg/m3.The ΣPCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/m3,0.050 to 0.859 pg(TEQ)/m3,respectively.The concentrations of ΣPBDEs ranged from 92 to 3086 pg/m3,with an average of 894 pg/m3.The pollution levels of PCDD/Fs,PCBs and PBDEs were higher than other urban sites,which may be associated with the E-waste dismantling activities.The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase.The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient(Kp) with the subcooled liquid vapor pressure(PL0).The measured particulate sorptions of PCDD/Fs,PCBs and PBDEs were compared with the predictions from Junge-Pankow model and Koa absorption model.The Junge-Pankow model well estimated the particulate fractions of PCBs.However,it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs.The predicted particulate fractions of PCDD/Fs and PCBs from Koa model fitted well with the measured data.展开更多
Polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and polychlorinated biphenyls(PCBs) were monitored in a seasonal passive sampling scheme during June 2008 and January 2009 to investigate the spatial concentrat...Polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and polychlorinated biphenyls(PCBs) were monitored in a seasonal passive sampling scheme during June 2008 and January 2009 to investigate the spatial concentration,congener profiles and evaluate the potential inhalation risk in different functional areas in Tianjin,China.The spatial air concentrations and I-TEQs ranged 1.08×102-8.19×10 3 fg m-3(average 2.63×103 fg m-3) and 4.08-325 fg I-TEQ m-3(average 91.4 fg I-TEQ m-3) respectively for PCDD/Fs.The concentration and I-TEQs of PCBs were 3.08×104-3.01×105 fg m-3(average 1.39×105 fg m-3) and 1.72-49.6 fg I-TEQ m-3(average 18.5 fg I-TEQ m-3).It is obvious that PCB concentrations were several hundred times higher than the PCDD/Fs.However,the ambient air PCDD/Fs contributed a major part to the total toxicity equivalents,varying from 72.7% to 89.0%(average 81.8%).The atmospheric PCDD/F levels were observed to be higher in winter for most of sampling sites in the downtown.Besides,inhalation risk assessment showed that local residents might suffer more risk near the point sources than those in living area,industrial zones and background area in Tianjin City.However,the total daily dioxin intake was approximately several to hundreds of times lower than the WHO criteria,showing relatively low exposure risks from the impact of industry point sources in Tianjin City.展开更多
Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinate...Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinated dibenzofurans （PCDFs） and polycyclic aromatic hydrocarbons （PAHs） were studied. Coal and calcium oxide （CaO） were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 μg/m^3 and 8955.93 pg/m^3 in the flue gas, respectively. In the case of cocombustion with coal （msludge/mcoal =1：1）, the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant effect of CaO on PCDD/Fs formation was observed.展开更多
The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） were investigated within a seasonally active ...The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m3 （average 69.3 fg I-TEQ/m3） in summer and （89.8-1.01） x 103 fg I-TEQ/m3 （average 509 fg I-TEQ/m3） in winter, respectively, except for the E-waste dismantling site where much higher values were observed （1.04 x 103 fg I-TEQ]m3 in summer and 7.123 x 103 fg I-TEQ/m3 in winter）. The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.展开更多
Sampling and analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） are both time-consuming and expensive. In principle, real-time monitoring of chlorobenzene （CBz） as an indicator for PCDD/Fs c...Sampling and analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） are both time-consuming and expensive. In principle, real-time monitoring of chlorobenzene （CBz） as an indicator for PCDD/Fs could be useful to control and optimize incinerator operating conditions. To test this strategy, CBz was analyzed together with PCDD/Fs in flue gas samples collected from a hospital waste incinerator. Moreover, lab experiments were conducted to investigate the effect of temperature and oxygen on CBz formation from fly ash from the same incinerator. The experimental results demonstrate that chlorobenzene （in particular PeCBz） correlate well with PCDD/Fs, in line with previous research. The optimum temperature of CBz formation is in a range of 350 to 400℃ and CBz yield increases significantly with oxygen, in line with PCDD/Fs formation. This study is useful for confirming the de novo mechanism and defining correlations between CBz and PCDD/Fs.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 20607025,20777079 and 20737007)
文摘Polychlorinated diebenzo-p-dioxins(PCDDs),polychlorinated diebenzofurans(PCDFs),polychlorinated biphenyls(PCBs) and polybrominated diphenyl ethers(PBDEs) were monitored in the ambient air of Taizhou,an E-waste dismantling area of southeast China to evaluate their concentrations,profiles and gas-particle partitioning.The ΣPCDD/Fs concentrations ranged from 2.91 to 50.6 pg/m3,with an average of 14.3 pg/m3.The I-TEQs for PCDD/Fs were in the range of 0.20-3.45 pg/m3,with an average of 1.10 pg/m3.The ΣPCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/m3,0.050 to 0.859 pg(TEQ)/m3,respectively.The concentrations of ΣPBDEs ranged from 92 to 3086 pg/m3,with an average of 894 pg/m3.The pollution levels of PCDD/Fs,PCBs and PBDEs were higher than other urban sites,which may be associated with the E-waste dismantling activities.The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase.The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient(Kp) with the subcooled liquid vapor pressure(PL0).The measured particulate sorptions of PCDD/Fs,PCBs and PBDEs were compared with the predictions from Junge-Pankow model and Koa absorption model.The Junge-Pankow model well estimated the particulate fractions of PCBs.However,it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs.The predicted particulate fractions of PCDD/Fs and PCBs from Koa model fitted well with the measured data.
基金supported by the Ministry of Environmental Protection of China for the Project of Toxic Substances in the Atmosphere and Their Effect to the Soil,the National Basic Research Program of China(2009CB421600)the National Natural Science Foundation of China(20890111,20907059)
文摘Polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and polychlorinated biphenyls(PCBs) were monitored in a seasonal passive sampling scheme during June 2008 and January 2009 to investigate the spatial concentration,congener profiles and evaluate the potential inhalation risk in different functional areas in Tianjin,China.The spatial air concentrations and I-TEQs ranged 1.08×102-8.19×10 3 fg m-3(average 2.63×103 fg m-3) and 4.08-325 fg I-TEQ m-3(average 91.4 fg I-TEQ m-3) respectively for PCDD/Fs.The concentration and I-TEQs of PCBs were 3.08×104-3.01×105 fg m-3(average 1.39×105 fg m-3) and 1.72-49.6 fg I-TEQ m-3(average 18.5 fg I-TEQ m-3).It is obvious that PCB concentrations were several hundred times higher than the PCDD/Fs.However,the ambient air PCDD/Fs contributed a major part to the total toxicity equivalents,varying from 72.7% to 89.0%(average 81.8%).The atmospheric PCDD/F levels were observed to be higher in winter for most of sampling sites in the downtown.Besides,inhalation risk assessment showed that local residents might suffer more risk near the point sources than those in living area,industrial zones and background area in Tianjin City.However,the total daily dioxin intake was approximately several to hundreds of times lower than the WHO criteria,showing relatively low exposure risks from the impact of industry point sources in Tianjin City.
基金supported by the Important Project on Science and Technology of Zhejiang Province of China(No. 2007C03003)the National Natural Science Foundation of China (No. 50576082)
文摘Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinated dibenzofurans （PCDFs） and polycyclic aromatic hydrocarbons （PAHs） were studied. Coal and calcium oxide （CaO） were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 μg/m^3 and 8955.93 pg/m^3 in the flue gas, respectively. In the case of cocombustion with coal （msludge/mcoal =1：1）, the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant effect of CaO on PCDD/Fs formation was observed.
基金supported by the Ministry of Environmental Protection of China for the Project of Toxic Substances in the Atmosphere and Their Effect to the Soilthe National Basic Research Program (973) of China(No.2009CB421600)the National Natural Science Foundation of China (No.20897011, 20907059)
文摘The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m3 （average 69.3 fg I-TEQ/m3） in summer and （89.8-1.01） x 103 fg I-TEQ/m3 （average 509 fg I-TEQ/m3） in winter, respectively, except for the E-waste dismantling site where much higher values were observed （1.04 x 103 fg I-TEQ]m3 in summer and 7.123 x 103 fg I-TEQ/m3 in winter）. The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.
基金supported by the National High-Tech Research and Development Program(863)of China(No. 2007AA06Z336)the Natural Science Foundation of Zhejiang Province(No.Z506214)
文摘Sampling and analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） are both time-consuming and expensive. In principle, real-time monitoring of chlorobenzene （CBz） as an indicator for PCDD/Fs could be useful to control and optimize incinerator operating conditions. To test this strategy, CBz was analyzed together with PCDD/Fs in flue gas samples collected from a hospital waste incinerator. Moreover, lab experiments were conducted to investigate the effect of temperature and oxygen on CBz formation from fly ash from the same incinerator. The experimental results demonstrate that chlorobenzene （in particular PeCBz） correlate well with PCDD/Fs, in line with previous research. The optimum temperature of CBz formation is in a range of 350 to 400℃ and CBz yield increases significantly with oxygen, in line with PCDD/Fs formation. This study is useful for confirming the de novo mechanism and defining correlations between CBz and PCDD/Fs.
