title: Increased formation of carcinogenic PAH metabolites in fish promoted by nitrite.
abstract: Nitrite (NO(2)(-)), a highly reactive chemical species, accumulates in coastal waters as a result of pollution with nitrogenous waste and/or an imbalance in the bacterial processes of nitrification and denitrification. The present study probed the impact of nitrite (NO(2)(-)) on the metabolism of polycyclic aromatic hydrocarbons (PAHs) in fish. In a laboratory experiment, exposure of euryhaline fish, Oreochromis mossambicus to industrial effluents containing PAHs in the presence of NO(2)(-) enhanced the cytochrome P450-dependent biotransformation activity determined as 7-ethoxyresorufin-O-deethylase (EROD), by nearly 36% compared to the value observed in the absence of NO(2)(-) (50.2 +/- 6.74 pmol resorufin min(-1) g(-1) liver). Fixed wavelength fluorescence measurements in bile revealed maximum enhancement to have occurred in the metabolites of benzo[a]pyrene, a carcinogenic PAH. Lasting, sublethal physiological deterioration was apparent in fish exposed simultaneously to an oil refinery effluent and NO(2)(-), from the unremittingly decreasing liver somatic index, even after the withdrawal of the contaminants.
authors.affiliation: National Institute of Oceanography, Dona Paula, Goa, India. shaila@darya.nio.org
authors.forename: M S
authors.initials: MS
authors.lastname: Shailaja
authors.forename: Rani
authors.initials: R
authors.lastname: Rajamanickam
authors.forename: Solimabi
authors.initials: S
authors.lastname: Wahidulla
mesh_terms: D000383:Agriculture; D000818:Animals; D001646:Bile / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis; D001711:Biotransformation; D002273:Carcinogens / Q000378:metabolism*; D004781:Environmental Exposure; D007220:Industrial Waste; D008099:Liver / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D017210:Tilapia / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D007220:Industrial Waste; D009573:Nitrites; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical