A Novel Compound, 9-Hydroxy-1-Nitropyrene, is a Major Photodegraded Compound of 1-Nitropyrene in the Environment

Abstract

1-Nitropyrene is a widely distributed environmental contaminant, but its fate in the environment remains unknown. 1-Nitropyrene in benzene exposed to sunlight was found to degrade rapidly, whereas 1-nitropyrene adsorbed on soot was stable and degraded at a rate of 42% in 40 d. The major degraded compound was identified as 9-hydroxy-1-nitropyrene, using nuclear magnetic resonance and gas chromatography/mass spectrometry. Concentrations of 9-hydroxy-1-nitropyrene were found to be between 15 and 23 pg/m3 in urban airborne samples. The mutagenic potency of 9-hydroxy-1-nitropyrene was much lower than that of 1-nitropyrene. We concluded that 1-nitropyrene in the environment is photodegraded into 9-hydroxy-1-nitropyrene to become a less mutagenic compound.

Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity

“…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).…”

“…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). Several publications contributed to the identification of some of the nine photoproducts: pyrene quinone (no information about the position of the oxygen) (86) Photolysis of 1-aminopyrene (AP) was first reported to produce the direct acting mutagen 1-nitropyrene and several other unidentified photoproducts (95,99).…”

“…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. Quinones are known reactive oxygen species sensitizers (28,31,147,148).…”

Photochemical reaction of nitro-polycyclic aromatic hydrocarbons: effect by solvent and structure

“…The likely photoreaction is oxidation of the aromatic rings. These are slower reactions than the nitro to nitrite rearrangement reaction [3, 15]. The relatively faster rate for 2-NF and 6-NC may be due to the quick conversion to the respective quinones [9].…”

Integrating Field Analyses with Laboratory Exposures to Assess Ecosystems Health

“…Photo-oxidation of the unsubstituted PAHs -two-ring naphthalene (Vialaton et al, 1999); three-ring anthracene (Mallakin et al, 2000) and phenanthrene (Wen et al, 2002); four-ring benz [a]anthracene (Dong et al, 2002) and pyrene (Sigman et al, 1998); and five-ring benzo [a]pyrene (Lee-Ruff et al, 1988) -can produce respective quinones, ring-open products or hydroxy-substituted products. In addition to quinones, hydroxy- (Koizumi et al, 1994), carboxy- (Zeng et al, 2002), hydroxymethyl-and formyl-PAHs or methyl-substituted PAHs are also detected among the photoproducts. Quinones are known sensitizers of reactive oxygen species, but are relatively stable against photo-oxidation.…”