Nitro-organic compounds, mutagenic

The larger concern about nitro-aromatic compounds is that environmental exposure to these molecules can cause cancer in humans and in other living organisms. Nitro-aromatic compounds are acutely toxic, mutagenic, and carcinogenic in laboratory mammals and in vitro test systems [6, 8]. Despite the potential negative impact of nitro-aromatic compounds on human health, they continue to be emitted into ambient air from municipal incinerators [9], motor vehicles (particularly from diesel exhausts) [10, 11], industrial power plants [12], and other sources. Evidence... 

Compared to the extensive data that have been obtained on the mutagenicity of nitro PAHs in S. typhimurium, relatively little is known about the metabolism of these compounds in this organism. Messier et al. (67) reported that incubation of 1-nitropyrene with S. typhimurium TA98 yielded 1-aminopyrene and 1-acetylaminopyrene as major and minor metabolites, respectively. The reduction of 1-nitropyrene was slow and was accompanied by a slow formation of DNA adducts. When incubations were conducted with the nitroreductase-deficient strain, TA100 F50, both the extent of 1-amino-pyrene formation and DNA binding decreased. Howard ej al. (71,115) also found reduction of 1-nitropyrene to 1-aminopyrene in strains TA98, TA1538 and ATCC 14028. 

Oxidation/hydroxylation of aromatic compounds by OH and HOONO is expected to enhance their degradation rate and hence decrease their lifetime on particulate matter, which in the case of pollutants is beneficial from the point of view of human health. Oxidation of PAHs could also lead to the production of photosensitizers such as quinones and aromatic carbonyls [10, 40, 41]. These compounds, if present in the gas phase, are also able to form aggregates and are therefore involved in the formation of secondary organic aerosol [42]. In contrast, nitration induced by OH + N02 or HOONO could lead to highly mutagenic nitro-PAHs [43] or phytotoxic nitrophenols [44, 45], in which case the health and environmental impact of the reaction intermediates is not negligible and is sometimes higher than that of the parent molecules. 

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