title: Diuron biotransformation and its effects on biofilm bacterial community structure.
abstract: The effect of realistic environmental contamination of diuron on natural epilithic biofilms dwelling bacterial communities and their transformation capacities were investigated by using microcosm experiments. Cobbles carrying biofilms from two sites ("Pau" and "Lacq") located in areas of contrasting pesticide use (urban and agricultural) on the Gave de Pau river (South-West France) were analysed. The water of the upstream site, Pau, was characterised by fewer pesticides than the water of Lacq, whereas concentrations were higher at Pau. The sampled cobbles were exposed to diuron (10 μg L(-1)) in microcosms. After 3 weeks of exposure, pesticides were analysed and bacterial community structures were assessed with terminal-restriction fragment length polymorphism (T-RFLP). Diuron was biotransformed during contact with biofilms, revealing that these communities contribute to the production of DCPMU (1-(3,4-dichlorophenyl)-3-methylurea) and DCPU metabolites (1-(3,4-dichlorophenyl) urea) in the river ecosystems. Bacterial communities from the most contaminated site appeared to be more resistant to diuron exposure. Correlation analyses combining chemical data with molecular fingerprinting showed that past in situ exposure drove the response of the bacterial communities.
authors.affiliation: Équipe Environnement et Microbiologie, UMR IPREM 5254, IBEAS, Université de Pau et des Pays de l'Adour, Avenue de l'Université, BP 1155, Pau cedex 64013, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Vercraene-Eairmal
authors.forename: Béatrice
authors.initials: B
authors.lastname: Lauga
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Saint Laurent
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mazzella
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutry
authors.forename: Maryse
authors.initials: M
authors.lastname: Simon
authors.forename: Solange
authors.initials: S
authors.lastname: Karama
authors.forename: François
authors.initials: F
authors.lastname: Delmas
authors.forename: Robert
authors.initials: R
authors.lastname: Duran
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000378:metabolism*; D044822:Biodiversity; D018441:Biofilms / Q000187:drug effects*; D001711:Biotransformation; D004237:Diuron / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D005618:Fresh Water / Q000737:chemistry; D006540:Herbicides / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity
chemical_list: D006540:Herbicides; D014874:Water Pollutants, Chemical; D004237:Diuron