Silver and copper accumulation in oyster Crassostrea gigas : geochemical tools for environmental message optimization

• Main Author: Mikolaczyk, Mathilde
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Jörg Schäfer, Gérard Blanc
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2016
• Subjects: Biomonitoring; Accumulation kinetics; Bioavailability; Copper; Silver; Cuivre; Argent; Biosurveillance; Cinétiques d’accumulation; Biodisponibilité; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; Crassostrea gigas
• Online Access: https://tel.archives-ouvertes.fr/tel-01423911; https://tel.archives-ouvertes.fr/tel-01423911/document; https://tel.archives-ouvertes.fr/tel-01423911/file/MIKOLACZYK_MATHILDE_2016.pdf

The data-base analyses of the French biomonitoring program (RNO/ROCCH, IFREMER, 2003-2014) in terms of silver (Ag) and copper (Cu) concentrations accumulation in oysters from 13 sites along the French Atlantic Coast showed spatial and time-dependent variations reflecting local pressures. The high Ag and Cu relations seems to be partly due to physiological processes involved in their bioaccumulation by oysters. The Cu/Ag elementary ratios showed an interesting potential for Ag and Cu sources detection, which were invisible through the use of only absolute concentrations characterized by a high individual variability. Chemical measurements and histological observations performed in wild oysters from Gironde Estuary showed a preferential Ag and Cu accumulation in the digestive gland with important cellular damages. The innovative isotope spiking method is highly sensitive and precise to observe rapid in vivo Ag and Cu accumulation kinetics through direct pathway using close-to-real exposure concentrations. The isotopic signals allowed to quantify the rapid MTE accumulation in the different organs and to observe the Ag and Cu co-regulation. Furthermore, it represents a real step forward in ecotoxicological experiments allowing to obtain the initial and final contamination state inside the same organism. The study of the trophic pathway suggested a higher Ag accumulation in algae than for Cu. The Ag and Cu potentially bioavailable fraction in estuarine particles was estimated respectively at 60% and 82%. The results showed that this estimation depends on the exposure time and sediment concentration, which can lead to important under-estimations. L’analyse des données de biosurveillance (RNO/ROCCH, IFREMER, 2003-2014) des concentrations en argent (Ag) et cuivre (Cu) dans les huîtres sauvages de 13 sites de la côte atlantique française a montré des variations spatio-temporelles reflétant les pressions locales. De fortes relations entre Ag et Cu semblent en partie dues à des facteurs physiologiques impliqués dans leur ...