title: Photodegradation of common environmental pharmaceuticals and estrogens in river water.
abstract: Photodegradation rates of five pharmaceuticals (gemfibrozil, ibuprofen, ketoprofen, naproxen, and propranolol) and of four estrogens (estriol, estrone [E1], 17beta-estradiol [E2], and 17alpha-ethinylestradiol [EE2]), which are common contaminants in the aquatic environment, were measured in both purified and river water at environmentally relevant concentrations (1-2 microg/L) and different oxygen concentrations. Solutions were irradiated with a xenon arc lamp (765 W/m2; 290 nm < lambda < 700 nm) and analyzed using a high-performance liquid chromatography-tandem mass spectrometry method with electrospray ionization for pharmaceuticals and atmospheric pressure photoionization for estrogens. In river water, half-lives were 4.1 min [corrected] for ketoprofen, 1.1 h [corrected] for propranolol, 1.4 h for naproxen, 2 to 3 h for estrogens, and 15 h for gemfibrozil and ibuprofen. In air-saturated purified water, rates generally were slower except for that of ketoprofen, which reacted with a half-life of 2.5 min. Naproxen, propranolol, and E1 reacted with half-lives of 1.9, 4.4, and 4.7 h, respectively. The EE2, estriol, E2, gemfibrozil, and ibuprofen reacted with half-lives of 28.4, 38.2, 41.7, 91.4, and 205 h, respectively. The presence of oxygen doubled the direct photolysis rates of naproxen and propranolol. In nonautoclaved river water, 80% of E2 rapidly biotransformed to E1 within less than 20 min, whereas all other compounds remained stable over 22 h.
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305-4020, USA.
authors.forename: Angela Yu-Chen
authors.initials: AY
authors.lastname: Lin
authors.forename: Martin
authors.initials: M
authors.lastname: Reinhard
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring / Q000379:methods; D004967:Estrogens / Q000737:chemistry*; D015248:Gemfibrozil / Q000737:chemistry; D006207:Half-Life; D007052:Ibuprofen / Q000737:chemistry; D007660:Ketoprofen / Q000737:chemistry; D009288:Naproxen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D010782:Photolysis; D011433:Propranolol / Q000737:chemistry; D045483:Rivers; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004967:Estrogens; D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical; D009288:Naproxen; D007660:Ketoprofen; D011433:Propranolol; D015248:Gemfibrozil; D010100:Oxygen; D007052:Ibuprofen