Characterization of PCDD/Fs and dioxin-like PCBs in flue gas from thermal industrial processes in Vietnam: A comprehensive investigation on emission profiles and levels

• Published in: Chemosphere (Oxford) 2019-06, Vol.225, p.238-246
• Main Authors: Pham, Mai Thi Ngoc, Anh, Hoang Quoc, Nghiem, Xuan Truong, Tu, Binh Minh, Dao, Thi Nhung, Nguyen, My Hang
• Format: Article
• Language: English
• Subjects: Dioxin-like PCBs; Flue gas; Metallurgy; PCDD/Fs; Vietnam; Waste incineration
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.03.024

The emission profiles and levels of unintentionally produced persistent organic pollutants (U-POPs) comprising polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were comprehensively investigated in flue gas released from 20 facilities belonging to 11 thermal industrial processes in Vietnam. Levels and patterns of PCDD/Fs and dl-PCBs in flue gas samples varied widely between sectors and different facilities in the same sector, suggesting different formation mechanisms involved. Flue gas concentrations of PCDD/Fs and dl-PCBs generally decreased in the order: industrial waste incinerator > secondary zinc production > coal fired craft boiler > coal fired power plant ≈ medical waste incinerator > steel production ≈ cement production > secondary copper production > coal fired industrial boiler > secondary tin production ≈ municipal waste incinerator. Results obtained from diagnostic ratio and fingerprint analysis have revealed that the stack emissions of PCDD/Fs and dl-PCBs were probably attributed to the de novo formation and incomplete destruction of input materials containing technical PCB oils or paints. The average emission factors of PCDD/Fs and dl-PCBs ranged from 0.011 to 374 μg WHO-TEQ tonne−1 for the studied facilities. A total emission amount of 4.89–11.4 g WHO-TEQ year−1 was estimated for the 20 facilities investigated in our study. This is the first comprehensive investigation on the unintentional emissions of PCDD/Fs and dl-PCBs from a wide range of industrial sectors in Vietnam. •PCDD/F and dl-PCB levels and profiles were examined in Vietnamese flue gas samples.•Industrial waste, zinc, and coal boiler flue gas contained elevated PCDD/F and dl-PCB levels.•Different formation mechanisms of PCDD/Fs and dl-PCBs were estimated.•TEQ emission factors and annual emission amounts were estimated.