Tracing cadmium contamination kinetics and pathways in oysters (Crassostrea gigas) by multiple stable Cd isotope spike experiments

• Published in: Ecotoxicology and Environmental Safety
• Main Authors: Strady, Emilie, Schäfer, Jörg, Baudrimont, Magalie, Blanc, Gérard
• Other Authors: UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (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), Environnements et Paléoenvironnements OCéaniques (EPOC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDE]Environmental Sciences; Pacific; Crassostrea gigas
• Online Access: https://hal.archives-ouvertes.fr/hal-02357365; https://hal.archives-ouvertes.fr/hal-02357365/document; https://hal.archives-ouvertes.fr/hal-02357365/file/Strady%20et%20al.,EESA%202011%20HAL.pdf; https://doi.org/10.1016/j.ecoenv.2010.10.020

International audience Laboratory experiments using stable Cd isotopes (110 Cd and 112 Cd) were conducted to separately and simultaneously characterize Cd accumulation in different tissues of Pacific oysters (Crassostrea gigas) via the (i) trophic and (ii) direct pathways. For this, we exposed juvenile oysters to 110 Cd-spiked seawater (110 Cd: 2 mg l À 1 constant level) and 112 Cd-spiked food (Thalassiossera weissflogii, 112 Cd: 2 mg l À 1 in 35 Â 10 3 cells/oyster/L) in four experimental treatment groups, each containing 6 oysters, for 21 days with constant trophic feeding. These Cd contamination levels were $ 10 times lower than those typically used in experimental accumulation studies. Three oysters per treatment group were dissected every 7 days with separate sampling of the gills, digestive gland and the rest of the body. Metallothioneins were analysed in the digestive gland and gills. Cadmium concentrations and isotope ratios were measured in water (daily) and tissues (weekly) by GF-AAS and ICP-MS. The observed time-dependant evolution in Cd concentrations and 110 Cd/ 114 Cd and 112 Cd/ 114 Cd isotope ratios clearly revealed the bio-accumulation short-term kinetics and pathways of Cd contamination in the different tissues. Under the experimental conditions, significantly changed isotope ratios in gills and the digestive gland of oysters suggested rapid and efficient contamination by 110 Cd derived from direct exposure followed by internal Cd transfer between organs. Trophic contamination became measurable after 14 days of exposure corresponding to a trophic transfer rate of 1%. Constant metallothionein levels during the experiment suggested that the initially present metallothionein levels were sufficient to deal with the experimental Cd exposure.