title: Diffuse urban pollution increases metal tolerance of natural heterotrophic biofilms.
abstract: This study is a first attempt to investigate the impact of urban contamination on metal tolerance of heterotrophic river biofilms using a short-term test based on β-glucosidase activity. Tolerance levels to Cu, Cd, Zn, Ni and Pb were evaluated for biofilms collected at three sites along an urban gradient in the Seine river (France). Metallic pollution increased along the river, but concentrations remained low compared to environmental quality standards. Biofilm metal tolerance increased downstream from the urban area. Multivariate analysis confirmed the correlation between tolerance and contamination and between multi-metallic and physico-chemical gradients. Therefore, tolerance levels have to be interpreted in relation to the whole chemical and physical characteristics and not solely metal exposure. We conclude that community tolerance is a sensitive biological response to urban pressure and that mixtures of contaminants at levels lower than quality standards might have a significant impact on periphytic communities.
authors.affiliation: Cemagref-Unité de Recherche Hydrosystèmes et Bioprocédés, Parc de Tourvoie, Antony, France. lise.fechner@cemagref.fr
authors.forename: Lise C
authors.initials: LC
authors.lastname: Fechner
authors.forename: Catherine
authors.initials: C
authors.lastname: Gourlay-Francé
authors.forename: Adeline
authors.initials: A
authors.lastname: Bourgeault
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Tusseau-Vuillemin
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena / Q000187:drug effects; D001426:Bacterial Proteins / Q000032:analysis / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000494:pharmacology*; D014506:Urban Renewal; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000494:pharmacology*; D014877:Water Pollution, Chemical / Q000032:analysis; D001617:beta-Glucosidase / Q000032:analysis / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D001617:beta-Glucosidase