Polychlorinated diphenyl ethers—A review

Becker, Mauro R.; Phillips, T. D.; Safe, Stephen

doi:10.1080/02772249109357761

Cited by 61 publications

(40 citation statements)

References 34 publications

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“…PCDEs are becoming of great concern because of their structural and toxicological similarity to polychlorinated biphenyls (Becker et al 1991). Studies indicate that PCDE congeners show a broad spectrum of toxic and biochemical responses in laboratory animals, including the induction of cytochrome P-450-dependent mono-oxygenase enzymes.…”

Section: Introductionmentioning

confidence: 99%

Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes

Liu

Zheng

Liu

et al. 2007

Environ Sci Pollut Res

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Section: Introductionmentioning

confidence: 99%

Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes

Liu

Zheng

Liu

et al. 2007

Environ Sci Pollut Res

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“…Industrially, DEs are finding increased uses as components of heat transfer media, as solvents, and in plasticizers (Francis, 1986). Polychlorinated DEs are manufactured for use as flame retardants and herbicides (Becker et al, 1991). Due to the marked toxicity of several congeners of the halogenated diaryl ethers and their general resistance to degradation, because of their physical, chemical, and biological stabilities (Hoffman et al, 1991), the study of mechanisms whereby such compounds may be degraded are of interest.…”

Section: Microbial Degradation Of De and 3-or 4-carboxy Dementioning

confidence: 99%

Bacterial degradation of aromatic compounds via angular dioxygenation.

Nojiri

Habe

Omori

2001

J. Gen. Appl. Microbiol.

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Dioxygenation is one of the important initial reactions of the bacterial degradation of various aromatic compounds. Aromatic compounds, such as biphenyl, toluene, and naphthalene, are dioxygenated at lateral positions of the aromatic ring resulting in the formation of cis-dihydrodiol. This "normal" type of dioxygenation is termed lateral dioxygenation. On the other hand, the analysis of the bacterial degradation of fluorene (FN) analogues, such as 9-fluorenone, dibenzofuran (DF), carbazole (CAR), and dibenzothiophene (DBT)-sulfone, and DF-related diaryl ether compounds, dibenzo-p-dioxin (DD) and diphenyl ether (DE), revealed the presence of the novel mode of dioxygenation reaction for aromatic nucleus, generally termed angular dioxygenation. In this atypical dioxygenation, the carbon bonded to the carbonyl group in 9-fluorenone or to heteroatoms in the other compounds, and the adjacent carbon in the aromatic ring are both oxidized. Angular dioxygenation of DF, CAR, DBT-sulfone, DD, and DE produces the chemically unstable hemiacetal-like intermediates, which are spontaneously converted to 2,2,3-trihydroxybiphenyl, 2-aminobiphenyl-2,3-diol, 2,3-dihydroxybiphenyl-2-sulfinate, 2,2,3-trihydroxydiphenyl ether, and phenol and catechol, respectively. Thus, angular dioxygenation for these compounds results in the cleavage of the three-ring structure or DE structure. The angular dioxygenation product of 9-fluorenone, 1-hydro-1,1a-dihydroxy-9-fluorenone is a chemically stable cis-diol, and is enzymatically transformed to 2-carboxy-2,3-dihydroxybiphenyl. 2-Substituted 2,3-dihydroxybiphenyls formed by angular dioxygenation of FN analogues are degraded to monocyclic aromatic compounds by meta cleavage and hydrolysis. Thus, after the novel angular dioxygenation, subsequent degradation pathways are homologous to the corresponding part of that of biphenyl. Compared to the bacterial strains capable of catalyzing lateral dioxygenation, few bacteria having angular dioxygenase have been reported. Only a few degradation pathways, CARdegradation pathway of Pseudomonas resinovorans strain CA10, DF/DD-degradation pathway of Sphingomonas wittichii strain RW1, DF/DD/FN-degradation pathway of Terrabacter sp. strain DBF63, and carboxylated DE-degradation pathway of P. pseudoalcaligenes strain POB310, have been investigated at the gene level. As a result of the phylogenetic analysis and the comparison of substrate specificity of angular dioxygenase, it is suggested that this atypical mode of dioxygenation is one of the oxygenation reactions originating from the relaxed substrate specificity of the Rieske nonheme iron oxygenase superfamily. Genetic characterization of the degradation pathways of these compounds suggests the possibility that the respective genetic elements constituting the entire catabolic pathway have been recruited from various other bacteria and/or other genetic loci, and that these pathways have not evolutionary matured.

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“…Similar to their analogues, PCDEs with lipophilic and persistent properties tend to bioaccumulate and biomagnify in food webs (Domingo, 2006). Some PCDEs may have biochemical and toxic effects similar to those of PCBs and PCDD/Fs (Becker et al, 1991). Furthermore, PCDEs may be converted to or form toxic PCDD/Fs by photolysis or pyrolysis (Norström et al, 1976;Lindahl et al, 1980;Liu et al, 2010), and have been observed in the flue gas and fly ash of waste incinerators (Kurz and Ballschmiter, 1995;Nakao et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Validation and Characterization of Persistent Organic Pollutant Emissions from Stack Flue Gases of an Electric Arc Furnace by Using a Long-Term Sampling System (AMESA®)

Wang

Lin

et al. 2014

Aerosol Air Qual. Res.

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A long-term sampling system, called the Adsorption Method for Sampling of Dioxins and Furans (AMESA), was used for long-term sampling (up to 168 hours) of an electric arc furnace (EAF) to obtain the representative flue gas samples. In order to have a comprehensive view of the emissions of persistent organic pollutants (POPs) from EAFs, six POPs, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PCDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs), were investigated. Tests showed the breakthroughs of PBDD/Fs and PBDEs are much larger (8.9%-43%), while the others are less than 3%. A significant increase in breakthrough with the increase in halogen numbers is observed, because highly halogen-substituted POPs tend to partition to the particulate-phase. Except for PCBs and PCDEs, whose percentages of the POPs in the rinses to the total POPs collected from the long-term samples (cartridges + rinses) are less than 7%, those of the other POPs are all greater than 30%. Therefore, the solvents from the rinses of the sampling probe and other components need to be combined with an XAD-2 cartridge for analyses. The PCBs and PBDEs are the most abundant pollutants in the stack flue gases of the EAF, and their mass concentrations are one to three orders higher than those of the other POPs. With regard to POPs with dioxin-like toxicity, the percentages of the contributed toxicities by PCDD/Fs, PCBs and PBBD/Fs are 87.1%, 11.7% and 1.2%. The close association that PBDEs and PBDD/Fs have with the concentrations and congener profiles is not present for PCDEs and PCDD/Fs, suggesting the need for further studies of the formation mechanisms of these analogues.

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Polychlorinated diphenyl ethers—A review

Cited by 61 publications

References 34 publications

Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes

Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes

Bacterial degradation of aromatic compounds via angular dioxygenation.

Validation and Characterization of Persistent Organic Pollutant Emissions from Stack Flue Gases of an Electric Arc Furnace by Using a Long-Term Sampling System (AMESA®)

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