Atmospheric oxidation mechansim of polychlorinated biphenyls (PCBs) initiated by OH radicals

Liao, Zhihong; Min, Zeng; Wang, Lingyu

doi:10.1016/j.chemosphere.2019.124756

Cited by 15 publications

(3 citation statements)

References 59 publications

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“…The metabolism is mediated through cytochrome P450 monooxygenase (CYP450) by direct electrophilic addition of oxygen or by the formation of a transient reactive arene oxide and the spontaneous rearrangement to OH-PCBs. − ,, OH-PCB metabolites formed in the living organisms can enter the food chain and be released into the environment . Abiotic formation of OH-PCBs has been demonstrated in the laboratory and in silico through the atmospheric reaction between volatile PCBs and hydroxyl radicals, − both of which are present in the atmosphere. , However, no study has directly observed the formation of OH-PCBs through this mechanism in the environment . OH-PCBs may be a result of advanced oxidation processes utilized in the treatment process because the concentrations of OH-PCBs in the surface waters collected near sewage treatment plants in urban areas were reported to be relatively higher than those collected from offshore from Lake Ontario …”

Section: Introductionmentioning

confidence: 99%

Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments

Saktrakulkla

Martínez

et al. 2022

Environ. Sci. Technol.

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We measured the concentrations of 837 hydroxylated polychlorinated biphenyls (OH-PCBs, in 275 chromatographic peaks) and 209 polychlorinated biphenyls (PCBs, in 174 chromatographic peaks) in sediments from New Bedford Harbor in Massachusetts, Altavista wastewater lagoon in Virginia, and the Indiana Harbor and Ship Canal in Indiana, USA and in the original commercial PCB mixtures Aroclors 1016, 1242, 1248, and 1254. We used the correlation between homologues and the peak responses to quantify the full suite of OH-PCBs including those without authentic standards available. We found that OH-PCB levels are approximately 0.4% of the PCB levels in sediments and less than 0.0025% in Aroclors. The OH-PCB congener distributions of sediments are different from those of Aroclors and are different according to sites. We also identified a previously unknown compound, 4-OH-PCB52, which together with 4′-OH-PCB18 made up almost 30% of the OH-PCBs in New Bedford Harbor sediments but less than 1.2% in the Aroclors and 3.3% in any other sediments. This indicates site-specific environmental transformations of PCBs to OH-PCBs. We conclude that the majority of OH-PCBs in these sediments are generated in the environment. Our findings suggest that these toxic breakdown products of PCBs are prevalent in PCB-contaminated sediments and present an emerging concern for humans and ecosystems.

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Section: Introductionmentioning

confidence: 99%

Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments

Saktrakulkla

Martínez

et al. 2022

Environ. Sci. Technol.

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“…It might be assumed that ratio of PCDDs/Fs and Dl-PCBs are deformed and reformed by heat through UV light degradation and oxidized in the environment. (Liao et al, 2020;Wang and Tang, 2011).…”

Section: Composition Of Dioxin In Ambient Air Sample In Thailandmentioning

confidence: 99%

Risk assessment of inhalation exposure to Polychlorinated dibenzo-p-dioxins, dibenzofurans and Dioxin-like PCBs in Ambient Air, Thailand

Boonyatumanond,

Rungsiriworapong,

Pornrattanapimolchai

et al. 2023

Preprint

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In order to assess the situation of air quality of Persistent Organic Pollutants (POPs), Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and Dioxin-like PCBs (Dl-PCBs) with a total of 29 isomers and their risk assessment were estimated from two hundred ambient air samples in Thailand since 2018–2022. A monitoring program was carried out in Mega-city, industrial area, landfill sites, haze pollution areas, industrial estate areas and National parks that would represent a clean area. The total concentrations of PCDD/Fs and Dioxin-like PCBs in Bangkok area ranged from 0.011–0.17 pg-TEQ/m3 and average total concentration was 0.059 pg-TEQ/m3. The calculation of Daily Inhalation Dose (DID) at an old industrial estate (Bangpoo) for adults weighing about 55–80 kg ranged from 0.12–0.19 pg-TEQ kg− 1day− 1 and the DID in children with ages less than 6 years old ranged from 0.060–0.090 pg-TEQ .kg− 1day− 1. The concentrations of PCDD/Fs detected at Bangpoo industrial estate was about ten times higher than Bangkok area. The estimated level of Cancer Risk (CR) or Carcinogenic Risk at Bangpoo industrial estate area and Bangkok area were 2.5 E-04 and 2.6 E-06 respectively. The data were analysed T-test as appropriate and statistical significance (two-sample assuming equal and unequal variances) was defined as p < 0.05.

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“…The investigation of these compounds' reactivity in different environments is of great interest to understand their degradation, which will allow the development of new treatment processes and a better understanding of the toxic effect on the environment and health. In the last decade, the reactivity of organochlorides and in particular the different enantiomers of the DDT, TCDD and PCBs, have been investigated through computational approach [28][29][30][31][32][33][34] . The degradation processes were investigated from molecular dynamics simulation on the DDT in a water-sediment environment, and several studies have implemented atmospheric reactions initiated by radicals such as OH, CH or molecules such as O 3 and H 2 O 2 .…”

Section: Please Cite This Article As Doi:101063/50120831mentioning

confidence: 99%

Development of a novel ReaxFF reactive potential for organochloride molecules

Wolf

Bégué

Vallverdu

2022

The Journal of Chemical Physics

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This article presents a new reactive potential in the ReaxFF formalism. It aims to include the chlorine element, and opens up the fields of use of ReaxFF to the whole class of organochloride compounds including conjugated or aromatic groups. Numerous compounds in this family raise global awareness due to their environmental impact, and such a reactive potential will help investigate their degradation pathways. The new force field belongs to the aqueous branch. The force field parameters were fitted against high-level quantum chemistry calculations, including CASSCF/NEVPT2 calculations and density functional theory calculations, and its accuracy was evaluated using a validation set. The root means square deviation against quantum mechanics energies is 0.38 eV (8.91 kcal/mol). From a structural point of view, the root means square deviation is about 0.06Å for the bond lengths, 11.86{degree sign} for the angles and 4.12{degree sign} for the dihedral angles. With CHONCl-2022_weak new force field, we successfully investigated the regioselectivity for nucleophilic or electrophilic attacks on polychlorinated biphenyls (PCB), which are toxic and permanent pollutants. The rotation barriers along the bond linking the two benzene rings, which is crucial in the toxicity of these compounds, are well reproduced by CHONCl-2022_weak. Then our new reactive potential is used to investigate the chlorobenzene atmospheric oxidation, initiated by a hydroxyl radical. The reaction pathways computed with ReaxFF agree with the quantum mechanics results. We showed that, in the presence of dioxygen molecules, the oxidation of chlorobenzene likely leads to the formation of highly oxygenated compounds after the abstraction of hydrogen radicals.

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Atmospheric oxidation mechansim of polychlorinated biphenyls (PCBs) initiated by OH radicals

Cited by 15 publications

References 59 publications

Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments

Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments

Risk assessment of inhalation exposure to Polychlorinated dibenzo-p-dioxins, dibenzofurans and Dioxin-like PCBs in Ambient Air, Thailand

Development of a novel ReaxFF reactive potential for organochloride molecules

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