title: Biodegradation of the ultraviolet filter benzophenone-3 under different redox conditions.
abstract: Biodegradation of the ultraviolet (UV) filter benzophenone-3 (BP-3) was investigated in the laboratory to understand its behavior and fate under oxic and anoxic (nitrate, sulfate, and Fe [III]-reducing) conditions. Biodegradation experiments were conducted in microcosms with 10% of activated sludge and digested sludge under oxic and anoxic conditions, respectively. Benzophenone-3 was well degraded by microorganisms under each redox condition. Under the redox conditions studied, the biodegradation half-life for BP-3 had the following order: oxic (10.7 d) > nitrate-reducing (8.7 d) > Fe (III)-reducing (5.1 d) > sulfate-reducing (4.3 d) ≥ anoxic unamended (4.2 d). The results suggest that anaerobic biodegradation is a more favorable attenuation mechanism for BP-3. Biodegradation of BP-3 produced two products, 4-cresol and 2,4-dihydroxybenzophenone, under oxic and anoxic conditions. Biotransformation of BP-3 to 2,4-dihydroxybenzophenone by way of demethylation of the methoxy substituent (O-demethylation) occurred in cultures under each redox condition. The further biotransformation of 2,4-dihydroxybenzophenone to 4-cresol was inhibited under oxic, nitrate-reducing, and sulfate-reducing conditions.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, PR China.
authors.forename: You-Sheng
authors.initials: YS
authors.lastname: Liu
authors.forename: Guang-Guo
authors.initials: GG
authors.lastname: Ying
authors.forename: Ali
authors.initials: A
authors.lastname: Shareef
authors.forename: Rai S
authors.initials: RS
authors.lastname: Kookana
mesh_terms: D001577:Benzophenones / Q000032:analysis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001711:Biotransformation; D003408:Cresols / Q000032:analysis / Q000378:metabolism; D006207:Half-Life; D009566:Nitrates / Q000032:analysis / Q000378:metabolism; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology; D013431:Sulfates / Q000032:analysis / Q000378:metabolism; D013473:Sunscreening Agents / Q000032:analysis / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D001577:Benzophenones; D003408:Cresols; D009566:Nitrates; D012722:Sewage; D013431:Sulfates; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical; C032538:4-cresol; C005290:oxybenzone