Untitled

Abstract

Phototransformation of aromatic pollutants (ethiofencarb, 4-chloro-2-methylphenol, nitrobenzene, propiconazole, acifluorfen and thiobencarb) in natural sunlight was investigated in various aqueous media: (i) in pure water, (ii) in natural water samples, and (iii) in pure water to which humic acid (HA) (10 mg L -1 ) had been added. Half-lives were measured and photoproducts assessed. In natural water samples and in HA solutions Aquat. Sci. 64 (2002) 207 -215 1015-1621/02/020207-9 © EAWAG, Dübendorf, 2002 Aquatic Sciences ethiofencarb and 4-chloro-2-methylphenol were found to disappear mainly by photosensitized reactions whereas the other compounds underwent mostly direct photolysis. Photosensitized transformations were shown to be largely due to photoreactants other than singlet oxygen and hydroxyl radicals. These species oxidize preferentially compounds bearing a phenolic OH group or an oxidizable S atom.

Photolysis, oxidation and subsequent toxicity of a mixture of polycyclic aromatic hydrocarbons in natural waters

“…It was found that both singlet oxygen and hydroxyl radicals were not important for the observed decay of the PAHs in both natural waters studied, using both UV lamp types. Similar results were obtained by Canonica and Freiburghaus [31] in regard to phenol photosensitization from DOM, and Vialaton and Richard [33] who reported no effect of these additives on 4-chloro-2-methylphenol and nitrobenzene photo-transformation.…”

“…Experiments to identify singlet oxygen and hydroxyl radicals were performed by adding 0.001M sodium azid or 0.085M 2-propanol to a mixture of PAHs solution. At neutral pH, azide ions scavenge both singlet oxygen and hydroxyl radicals at rate constants of 7.9 × 10 8 M −1 s −1 and 1.2 × 10 10 M −1 s −1 respectively, and 2-propanol scavenge hydroxyl radicals at rate constant of 1.9 × 10 10 M −1 s −1 [33]. It was found that both singlet oxygen and hydroxyl radicals were not important for the observed decay of the PAHs in both natural waters studied, using both UV lamp types.…”

“…Loibner et al [17] found additive bioluminescence inhibition effects to V. fischeri for low molecular weight PAHs acenaphthene (ACE), FLU, phenantherene (PHE), naphthalene, and acenaphthylene. For a mixture of ACE, FLU, PHE, and pyrene, Swartz et al [33] observed antagonistic interactions for the amphipod Rhepoxynius abronius. Verrhiest et al [45] found synergistic PAHs interactions of PHE, FLU, and benzo[k]fluoranthene measured in wholesediment tests using Daphnia magna, Hyallela azteca, and Chironomus riparius as test organisms.…”

Aquatic Phototransformation of Organic Contaminants Induced by Coloured Dissolved Natural Organic Matter

“…The high production volume chemical, 4-chloro-2-methylphenol, XVI was photolysed in distilled and natural waters and aqueous solutions of soilextracted humic substances (Ranker, Spain) under various irradiation conditions: with monochromatic light at 280 nm, using polychromatic lamps emitting between 300 and 450 nm, and in natural sunlight (June, ClermontFerrand, France) [78,79].…”

Chemical Dosimetry System for γ-Ray Irradiation Based on the Formation of Phenol from Aqueous Benzene Solutions

“…[4][5][6][7][8] For the determination of hydroxyl radicals, many chemical probe methods based on the determination of products formed by reactions between hydroxyl radicals and probe compounds have been reported. In these methods, benzene, 4,5,9 nitrobenzene, 10 benzoic acid, 11,12 terephthalate, 13 2-propanole, 13 methanol 11 and dimethyl sulfoxide 14 were used as the probe compounds. The benzene probe method in which phenol formed from benzene and hydroxyl radicals is determined by HPLC is a simple, rapid, low-cost and highly sensitive method for determining the photochemical formation of hydroxyl radicals in environmental water.…”