Photodecomposition of 1-nitropyrene and other direct-acting mutagens extracted from diesel-exhaust particulates

Stärk, G.; Stauff, J.; Miltenburger, H.G.; Stumm-Fischer, I.

doi:10.1016/0165-1218(85)90021-7

Cited by 29 publications

(18 citation statements)

References 17 publications

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“…19 No evidence of a direct NO 2 dissociation of the first excited singlet or triplet state into a pyrenyl radical was obtained since pyrene, a product that could result from a hydrogen atom abstraction from the solvent by this radical was not detected (Scheme 1). This product was reported by Stark 17 . Others reported products such as aminopyrene 45 , methoxypyrene 20 and hydroxymethylpyrene 20 were not observed in this study.…”

Section: Discussionmentioning

confidence: 66%

Photodegradation Mechanisms of 1-Nitropyrene, an Environmental Pollutant: The Effect of Organic Solvents, Water, Oxygen, Phenols, and Polycyclic Aromatics on the Destruction and Product Yields

García-Berríos

Arce

2012

J. Phys. Chem. A

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This work describes studies of the photodegradation mechanism of 1-Nitropyrene (1-NO2Py) in a chemical model system consisting of an organic solvent and known constituents of an aerosol particle. Photoproducts such as 1-hydroxypyrene (1-OHPy), 1-hydroxy-x-nitropyrenes (1-OH-x-NO2Py), 1-nitrosopyrene and 1,6- and 1,8-pyrenediones were identified by HPLC and HPLC-MS techniques and their quantum yields show a significant dependence on the type of solvent. The photodegradation quantum yield of 1-NO2Py, ϕ(−1−NO2Py), was larger in toluene, benzene and polar protic solvents (10−3) in comparison with nonpolar and polar aprotic solvents, where the yield is in the order of 10−4. In solvents with an abstractable hydrogen atom the products formed in higher yields were 1-OHPy and 1-OH-x-NO2Py. These represent 60 to 80% of the photodestruction yield and result from abstraction and recombination reactions of the pyrenoxy radical, an intermediate postulated to be formed as a result of a nitro-nitrite rearrangement in nitroaromatics. The small O2 effect in the photodegradation yield and the quenching experiments with azulene demonstrate the small contribution of the 3(π,π*) state in the 1-NO2Py photoreaction. The nitrosopyrene product was not observed under these conditions, demonstrating the participation of the 3(π,π*) state in its formation. In the presence various phenols aerosol constituents the photodegradation yield increased by ten fold in all solvents. This effect is partly ascribed by the reaction of 3(π,π*) state with the phenol. The effect of water resulted in the reduction of the 1-NO2Py photodegradation yield and of its photoproducts. The phototodegradation of 1-NO2Py was also studied in a viscous solvent, hexadecane, and it was determined that this medium does not inhibit its photodecay.

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Section: Discussionmentioning

confidence: 66%

Photodegradation Mechanisms of 1-Nitropyrene, an Environmental Pollutant: The Effect of Organic Solvents, Water, Oxygen, Phenols, and Polycyclic Aromatics on the Destruction and Product Yields

García-Berríos

Arce

2012

J. Phys. Chem. A

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“…Nitro-PAHs with a perpendicular nitro group are less mutagenic than those with a parallel nitro group due to their inability to be metabolized into reactive intermediates that form covalent DNA adducts [187,194]. Nitro-PAHs with a parallel nitro groups undergo photooxidation of the aromatic rings [195][196][197].…”

Section: Photoirradiation Of Nitro-pahsmentioning

confidence: 99%

Phototoxicity and Environmental Transformation of Polycyclic Aromatic Hydrocarbons (PAHs)—Light-Induced Reactive Oxygen Species, Lipid Peroxidation, and DNA Damage

Xia

Sun

et al. 2012

Journal of Environmental Science and Health, Part C

196

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Polycyclic aromatic hydrocarbons (PAHs) are a class of mutagenic and tumorigenic environmental contaminants. Although the mechanisms by which PAHs induce cancer in experimental animals have been extensively studied and the metabolic activation pathways have been determined, the environmental fate of PAHs and the phototoxicity exerted by PAHs, as well as their photoreaction products formed in the environment, have received much less attention. In this review, the formation of oxygenated PAHs, PAH quinones, nitro-PAHs, and halogenated PAHs from photoreaction of environmental PAHs are addressed. Upon light irradiation, PAHs and all PAH photoreaction products can absorb light energy to reach photo-excited states, which react with molecular oxygen, medium, and coexisting chemicals to produce reactive oxygen species (ROS) and other reactive intermediates, such as oxygenated PAHs and free radicals. These intermediates, including ROS, induce lipid peroxidation, and DNA damage including DNA strand breakage, oxidation to 8-oxo-2'-deoxyguanosine, and DNA-adducts. Since these toxicological endpoints are associated with age-related diseases, including cancer, environmental PAHs concomitantly exposed to sunlight may potentially promote human skin damage, leading to ageing and skin cancers. Thus, we suggest that (i) in addition to the widely recognized metabolic pathways, more attention must be paid to photoreaction as an important activation pathway for PAHs, (ii) risk assessment of environmental PAHs should take into consideration the complex photochemical reactions leading to mixtures of products that are also phototoxic; and (iii) the study of structure-toxicity relationships should be expanded to cover the complex photoreactions and extrinsic factors that affect phototoxicity endpoints.

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“…The photochemical reaction of these nitro-PAHs is complex due to the formation of complex mixture of photoproducts. This is probably why most of these photodegradation products have not been isolated and characterized, although the photodegradation of some of this type of nitro-PAHs have been studied (82,(84)(85)(86)(91)(92)(93). To have a look of the difficulty of studying the photochemical reaction of this type of nitro-PAHs, one can look at the nine photodecomposition products for 1-nitropyrene (85,86,93).…”

Section: Pah Photochemistrymentioning

confidence: 99%

“…The photochemical degradation of nitro-PAHs mainly leads to photo-oxidation products. The photochemical reaction rate of nitro-PAHs depends on the position of the nitro-substitution (82,(84)(85)(86)(87). Nitro groups peri to two hydrogen atoms is forced to be in a perpendicular orientation to the aromatic ring due to steric hindrance while nitro groups peri only to one hydrogen atom stay in a parallel orientation to the aromatic ring (18,22,33,83) (Figure 9).…”

Section: Pah Photochemistrymentioning

confidence: 99%

“…Larger ring PAHs are relatively rare and their photoproducts can be more complex due to greater complexity of the rings. Photo-oxidation of some nitro (56,82,84,86,(88)(89)(90)146), amino (94)(95)(96)102), and hydroxy (71) PAHs also lead to quinones. In addition to quinones, hydroxy (53,65,67,93), carboxy (53), hydroxymethyl and formyl-PAHs for methyl substituted PAHs (70) are also detected among the photolysis products.…”

Section: Perspectivesmentioning

confidence: 99%

See 1 more Smart Citation

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

2002

Journal of Environmental Science and Health, Part C

341

252

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Photodecomposition of 1-nitropyrene and other direct-acting mutagens extracted from diesel-exhaust particulates

Cited by 29 publications

References 17 publications

Photodegradation Mechanisms of 1-Nitropyrene, an Environmental Pollutant: The Effect of Organic Solvents, Water, Oxygen, Phenols, and Polycyclic Aromatics on the Destruction and Product Yields

Photodegradation Mechanisms of 1-Nitropyrene, an Environmental Pollutant: The Effect of Organic Solvents, Water, Oxygen, Phenols, and Polycyclic Aromatics on the Destruction and Product Yields

Phototoxicity and Environmental Transformation of Polycyclic Aromatic Hydrocarbons (PAHs)—Light-Induced Reactive Oxygen Species, Lipid Peroxidation, and DNA Damage

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

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