title: What are the outcomes of an industrial remediation on a metal-impacted hydrosystem? A 2-year field biomonitoring of the filter-feeding bivalve Corbicula fluminea.
abstract: The Riou-Mort watershed (southwest France) exhibits high metal contaminations (Cd and Zn) related to an important mining past. In this context, a remediation process has been implemented in 2007 to reduce the watershed contamination. The aim of this study was to assess the early effectiveness of the remediation process on the hydrosystem contamination state. A biomonitoring was realized over two years (2008-2010) with the filter-feeding bivalve Corbicula fluminea, exposed along a contamination gradient. Several biological parameters were monitored: (1) Cd and Zn bioaccumulation, (2) Metallothionein (MT) production as detoxification mechanism, (3) differential gene expression (cat, sod, gst, 12S, cox1, mt). The physicochemical data highlighted strong metal contamination persistence in the river water and failed to demonstrate a significant decrease of metal contamination during the 2-year monitoring. The bioaccumulation results confirmed the persistence of a water contamination despite remediation works, with maximum values measured downstream from the industrial site (Joany). The bioaccumulation increased in 2010, reaching 69.3±5.3 μg Cd g(-1) DW at Joany in July 2010, whereas it did not exceed 1.4±0.2 μg Cd g(-1) DW at the reference site throughout the biomonitoring. MT concentrations were closely related to the contamination gradient, especially at Joany, demonstrating their strong involvement in the detoxification processes. The mt gene induction was strongly correlated to the MT and metal concentrations. The gene inductions of cat, sod, gst and 12S were correlated to both the metal concentrations and the seasonal variations, especially temperatures. This suggests that environmental factors require serious consideration for the interpretation of bioaccumulation kinetics and thus for the assessment of the remediation effectiveness. Consequently, the whole results did not yet highlight strong beneficial effects of remediation work on the hydrosystem contamination state. First benefits of that process should be progressively felt, once the remediation achieved, and should grandly accelerate the decontamination process of the contaminated area.
authors.affiliation: University of Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, F-33405 Talence, Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Arini
authors.affiliation: University of Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, F-33405 Talence, Cedex, France.
authors.forename: G
authors.initials: G
authors.lastname: Daffe
authors.affiliation: University of Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, F-33405 Talence, Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Gonzalez
authors.affiliation: University of Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, F-33405 Talence, Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Feurtet-Mazel
authors.affiliation: University of Bordeaux 1, UMR CNRS 5805 EPOC, Place du Docteur Peyneau, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, F-33405 Talence, Cedex, France. Electronic address: m.baudrimont@epoc.u-bordeaux1.fr.
authors.forename: M
authors.initials: M
authors.lastname: Baudrimont
mesh_terms: D000818:Animals; D002104:Cadmium / Q000032:analysis*; D049874:Corbicula / Q000737:chemistry* / Q000378:metabolism; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation; D005602:France; D005618:Fresh Water / Q000737:chemistry; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D008906:Mining; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015032:Zinc / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc
keywords: Corbicula fluminea; Gene expression; Metallothioneins; Recovery, metals; Remediation