High Abundance of Unintentionally Produced Tetrachlorobiphenyls (PCB47/48/75, 51, and 68) in the Atmosphere at a Regional Background Site in East China

Abstract

Although polychlorinated biphenyls (PCBs) have been banned for several decades, they are still detected with elevated levels due to their unintentional production from combustion and industrial thermal processes (UP-PCBs). To investigate the composition and current levels of UP-PCBs and understand which sources are controlling PCB burdens in ambient atmosphere, air samples were collected from August 2012 to August 2015 at a background site in east China. An unexpected high abundance of PCB47+48+75 was observed to be the predominant congener with an average concentration of 786 ± 637 pg/m3. It accounted for 48 ± 16% of ΣPCBs, followed by PCB51 (10 ± 4%), PCB11 (8 ± 6%), and PCB68 (7 ± 3%). Seasonal variations with high levels in summer and lowest levels in winter were observed for PCB47+48+75, 51, and 68. These tetrachlorobiphenyl congeners were strongly correlated with temperature (r 2 > 0.7), suggesting the control of temperature-dependent volatilization processes from contaminated surfaces. The decreased occurrence of PCB47+48+75, 51, and 68 in commercial products and their negative correlations (|r| < 0.35) with polycyclic aromatic hydrocarbon (PAHs) and weak correlation with other PCB congeners suggested unique unintentional sources that differ from combustion and industrial thermal processes or pigment, such as the use of polymer sealant, for PCB47+48+75, 51, and 68 in the ambient air.

Evidence for Major Contributions of Unintentionally Produced PCBs in the Air of China: Implications for the National Source Inventory

“…Previous studies have mainly focused on a selection of congeners which was dominated by IP-PCBs. 12,17,18 However, several monitoring studies have recently pointed out that that UP-PCBs, such as PCB 47/48/75 7 and PCB 11 [19][20][21] contribute significantly to the present level of PCBs. Hence, monitoring merely based on a limited number of PCB congeners could bias the estimated contribution from various PCB sources.…”

Oxidative potential of solvent-extractable organic matter of ambient total suspended particulate in Bangkok, Thailand

“…Factor 2 had high loadings from Σ 3-ring PAHs and alkanes. Since 3-ring PAHs (Phe, Ant, and Fla) and alkanes (C 15 –C 33 ) are mainly derived from domestic cooking and petroleum/diesel evaporation, 78,79 Factor 2 was attributed to oil fume emissions, and is prominent in dry I and dry II season. Factor 3 was dominated by terephthalic acid, which is commonly released by burning plastic materials.…”

Polycyclic Aromatic Carbon: A Key Fraction Determining the Light Absorption Properties of Methanol-Soluble Brown Carbon of Open Biomass Burning Aerosols

“…Analytical methods and data of other components, including organic and elemental carbon of bulk aerosols (OC and EC), water- and methanol-soluble organic carbon (WSOC and MSOC, respectively), and priority PAHs, as well as the UV–visible absorption spectra of WS-BrC and MS-BrC, have been described previously. ,, These data will be described briefly below.…”