A mechanistic approach to evaluate the influence of Cd and Zn on 57Co, 110mAg and 134Cs accumulation and depuration by a freshwater mussel (Dreissena polymorpha).
C. Adam, B. Fraysse, J. Garnier-Laplace, J.P. Baudin and A. Boudou
Actes du congrès ECORAD, 3-7 sept 2001, Aix en Provence, France
Radioprotection - Colloques, volume 37, C1-847/ C1-852.
The effects of Cd and Zn on 110mAg, 57Co and 134Cs uptake and depuration in the freshwater mussel Dreissena polymorpha were investigated under laboratory controlled conditions. Differences at the whole body level were identified between groups exposed to radionuclides alone or to radionuclides and metals under different conditions (Cd or Zn alone or a mixture of Cd and Zn). The accumulation of 57Co was reduced in the presence of Zn, at the whole organism level and in the soft body. On the opposite, 134CS increased in the presence of Cd or Zn, Finally, 110mAg uptake decreased in the presence of both metals in the whole organism but increased in the soft tissues. Two hypotheses related to the major mechanisms governing the influence of metals on radionuclides were tested. First, the uptake was hypothesised to be directly related to the filtration rate, which has been shown to decrease with increasing zinc concentrations. On the other hand, whole organism zinc regulation mechamsms may include the radioactive pollutant as well. None of these two hypotheses could be validated. Consequently, further explanations were provided to link metal exposure to the radionuclide uptake by the bivalves.