Measurement of atmospheric PCDD/F and PCB distributions in the vicinity area of Waelz plant during different operating stages.
A comprehensive sampling program was conducted at four sampling sites in the vicinity area of a Waelz plant prior to and after the retrofitting of this plant for reducing PCDD/F (polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran) and polychlorinated biphenyl (PCB) emission to evaluate its effects on atmospheric PCDD/F and PCB concentrations. During the shutdown stage of the Waelz plant investigated, the atmospheric PCDD/F and PCB concentrations measured in the vicinity area (sites A, B and C) range from 24 to 170 fg-I-TEQ/m(3) and 5.0 to 8.2 fg-TEQ(WHO)/m(3), respectively. As the facility restarted to operate, the atmospheric PCDD/F and PCB concentrations measured increased to 570-1460 fg-I-TEQ/m(3) and 23-59 fg-TEQ(WHO)/m(3), respectively. When activated carbon injection (ACI) was adopted in the facility in early 2006, the PCDD/F concentrations measured in stack gas decreased dramatically from 190 to 3.4 ng-I-TEQ/Nm(3), while the PCB concentrations decreased from 4.9 to 0.08 ng-TEQ(WHO)/Nm(3). In the meantime, the atmospheric PCDD/F and PCB concentrations measured at sites A, B and C decreased to 150-340 fg-I-TEQ/m(3) and 13-19 fg-TEQ(WHO)/m(3), respectively. However, relatively high PCDD/F (180-1460 fg-I-TEQ/m(3)) and PCB (9.3-59 fg-TEQ(WHO)/m(3)) concentrations were measured at site D during all sampling stages. Overall, atmospheric sampling results indicate that over 50% of PCDD/Fs distributed in solid phase, while over 90% of PCBs distributed in vapor phase during all sampling stages.
Research Center for Environmental Changes, Academia Sinica, Taipei 115, Taiwan.
Kai Hsien
KH
Chi
Moo Been
MB
Chang
Shu Hao
SH
Chang
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control; D001572:Benzofurans / Q000032:analysis*; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D017745:Incineration; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D013624:Taiwan
D000393:Air Pollutants; D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D011078:Polychlorinated Biphenyls