Concentrations of PCDD/Fs and dl-PCBs in ambient air in Hanoi, Vietnam, between 2017 and 2021, and health risk assessments

Abstract

The concentrations and seasonal and temporal variations in polychlorodibenzo-pdioxins/polychlorodibenzofurans (PCDDs/PCDFs) and dioxin-like polychlorobiphenyls (dl-PCBs) in ambient air from November 2017 to September 2021 were investigated via passive air samplers containing polyurethane foam (PUF) discs in three residential areas, including the Cau Giay (CG) urban, Quang Minh (QM) industrialsuburban and Ba Vi (BV) rural areas, Hanoi, Vietnam. The average total toxic equivalent value of PCDDs/PCDFs and dl-PCBs (∑TEQ D/F&dl ) in the QM area was the highest (506 fg/PUF/day) and ranged from 317 to 752 fg/PUF/day. Compared to that in the QM area, the average ∑TEQ D/F&dl value was lower in the CG area (372 to 615 fg/PUF/day; average: 482 fg/PUF/day), and the lowest value occurred in the BV area, ranging from 121 to 414 fg/PUF/day with an average of 231 fg/PUF/day. Air pollution involving PCDDs/PCDFs and dl-PCBs increased during spring and winter. The highest seasonal average ∑TEQ D/F&dl value in the CG area was 534 fg/PUF/day in winter. The highest average ∑TEQ D/F&dl values in the QM and BV areas were 653 and 280 fg/PUF/day, respectively, in spring. The average daily dose (ADD) values of PCDDs/PCDFs and dl-PCBs through inhalation for adults in the three areas were minimal (9.9 to 96.2 fg TEQ/kg body weight (BW)/day) and below the 10% threshold of the tolerable daily intake (TDI) value recommended by the World Health Organization (100 to 400 fg TEQ/kg BW/day). For children, the ADD values (15.1 to 243.6 fg TEQ/kg BW/day) were less than and within of 10% of the recommended TDI value.

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

“…Fifteen 13 C-labeled 2,3,7,8-substituted PCDD/Fs at 2 and 4 ng of each compound were diluted from a stock solution of EDF-8999 as surrogates. The surrogates were spiked on each PUF disc at the beginning of PAS deployment, as described in our previous studies (Sau et al 2021;Sau 2023).…”

“…Before extraction of the PAS samples, twelve 13 C-labeled dl-PCBs for quanti cation of dl-PCBs and two recovery standards ( 13 C-labeled 1,2,3,4-TCDD and 1,2,3,7,8,9-HxCDD) for determination of the retention e ciency of surrogates were added to the PUF discs. Subsequently, the 37 Cl-labeled 2,3,7,8-TCDD clean-up standard and 13 C-labeled dl-PCB recovery standards were added to the extract (Sau 2023). Then, the extracts were prepared according to the US EPA method 1613 (US EPA 1994) and the US EPA method 1668 (US EPA 2008).…”