Temporal variations in the concentrations of PCDD/Fs and dl-PCBs in ambient air at Da Nang airport, Vietnam, and health risk assessments

Abstract Air pollution by polychlorodibenzo-p-dioxins/polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in three residential areas north, west, and south of Da Nang airport, was determined by using passive air samplers containing polyurethane foam (PUF) discs with three-month sampling intervals from 2017 to 2020. The total toxic equivalents (∑TEQs) of the PCDD/Fs and dl-PCBs, using WHO2005-TEFs, were highest north of the airport (134 to 10610 fg WHO-TEQ/PUF day with an average of 1108 fg WHO-TEQ/PUF day). ∑TEQs were lower west of the airport, between 159 and 381 fg WHO-TEQ/PUF day, and averaged 230 fg WHO-TEQ/PUF day. The lowest ∑TEQs were south of the airport, with a range of 76 and 331 fg WHO-TEQ/PUF day and an average of 152 fg WHO-TEQ/PUF day. Construction activities, including excavation and transportation of dioxin-contaminated soil north of the airport, have increased ambient air PCDD/F and dl-PCB contamination and health risks. The average daily dose values of PCDD/Fs and dl-PCBs through inhalation (ADDA) for residents north of the airport were the highest (10.9 to 3434 fg WHO-TEQ/kg BW/day and average: 597 fg WHO-TEQ/kg BW/day). Residents west of the airport faced lower health risks (13-123 fg WHO-TEQ/kg BW/day and average: 39 fg WHO-TEQ/kg BW/day). Residents south of the airport were exposed to a minimum of 6.2-107 fg WHO-TEQ/kg BW/day, with an average of 28 fg WHO-TEQ/kg BW/day. The maximum and average ADDA values for residents north of the airport exceeded 10% of the tolerable daily intake (TDI) recommended by the WHO (100-400 fg WHO-TEQ/kg BW/day). In comparison, all ADDA values for residents west and south of the airport were less than and within 10% of the TDI.