title: Chlorpropham and phenisopham: phototransformation and ecotoxicity of carbamates in the aquatic environment.
abstract: In this study, a comparison of two carbamic pesticides, chlorpropham and phenisopham, was carried out in terms of both photodegradability and ecotoxicity. The photochemical behaviour of the two pesticides was investigated under environmental-like conditions (aqueous media, UVB or solar irradiation). The photochemical kinetic parameters were calculated by irradiating 5 × 10(-5) M solutions (H₂O-CH₃CN, 9 : 1 v/v) using UVB lamps. For chlorpropham and phenisopham similar half-life times (39.0 and 55.0 min) were determined. Irradiation by sunlight leads to longer degradation half-life times (about 3 months), while it is possible to observe the formation of the same photoproducts. The well-known dechlorination reaction to a hydroxyphenylcarbamate was observed for chlorpropham. Phenisopham undergoes photo-Fries reaction to give rearranged products (hydroxybenzamides) and fragmentation products (hydroxyphenylcarbamate and N-ethylaniline). Acute and chronic toxicity tests of pesticides and their photoproducts were performed on organisms from two levels of the freshwater aquatic chain, the anostraca crustacean Thamnocephalus platyurus, the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata. The acute results showed that chlorpropham had median lethal concentrations for the crustacean T. platyurus and the rotifer B. calyciflorus of 10.16 and 35.19 mg L(-1), respectively, and phenisopham did not show any acute toxicity as the derivatives up to 10 mg L(-1). The only exception was N-ethylaniline which exhibited an acute LC₅₀ value of 0.46 mg L(-1). Phenisopham was the most toxic in the long term exposure while its five derivatives showed lower chronic potential for rotifers and algae. The same trend was observed for chlorpropham except for rotifers.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126 Napoli, Italy. ftemussi@unina.it.
authors.forename: Monica
authors.initials: M
authors.lastname: Passananti
authors.forename: Margherita
authors.initials: M
authors.lastname: Lavorgna
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Iesce
authors.forename: Marina
authors.initials: M
authors.lastname: DellaGreca
authors.forename: Emma
authors.initials: E
authors.lastname: Criscuolo
authors.forename: Alfredo
authors.initials: A
authors.lastname: Parrella
authors.forename: Marina
authors.initials: M
authors.lastname: Isidori
authors.forename: Fabio
authors.initials: F
authors.lastname: Temussi
mesh_terms: D000818:Animals; D002219:Carbamates / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D002748:Chlorpropham / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D054750:Ecotoxicology; D010782:Photolysis; D018570:Risk Assessment; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000528:radiation effects / Q000633:toxicity*
chemical_list: D002219:Carbamates; D014874:Water Pollutants, Chemical; D002748:Chlorpropham