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Biokinetics of selected heavy metals and radionuclides in the common Mediterranean echinoid Paracentrotus lividus: Sea water and food exposures

par Warnau, Michel ;Teyssié, Jean-Louis;Fowler, Scott W.
Référence Marine ecology. Progress series, 141, 1-3, page (83-94)
Publication Publié, 1996-10

Article révisé par les pairs

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Résumé :

Uptake and loss kinetics of Zn, Ag, Cd, 134Cs, and 241Am by the echinoid Paracentrotus lividus contaminated through either water or food were determined in controlled laboratory radiotracer experiments using low contaminant concentrations. The echinoid efficiently accumulated most of the elements from water. The only exception was 134Cs (concentration factor at steady state = 2.7). With respect to relative metal bioavailability, concentrations in the different body compartments of P. lividus were generally ranked in the order: digestive wall > gonads ≤ body wall > Aristotle's lantern > coelomic fluid. However, for 241Am, body wall uptake was as efficient as that of the digestive wall. The loss kinetics for Zn, Ag and 134Cs were described by a 2-component model whereas loss of Cd and 241Am was linear during the time course of the experiment. Loss of the different elements was relatively slow, except for 134Cs, whose long-lived loss component was characterized by a biological half-life of 6 d. Loss of the different elements ingested with food was described by a single-component model for Cd, 134Cs, and 241Am and by a 2-component model for Zn and Ag. Parameters of the kinetics indicate that all (for Cd, 134Cs, and 241Am) or most (for Zn and Ag) of the ingested amount of element is readily lost from the organism with the faeces. However, estimation of the assimilated fraction of elements ingested by the echinoids suggests that food could contribute significantly t the iota body burden of Ag in P. lividus.