Impact of cadmium and zinc prior exposure on 110m Silver, 58+60 Cobalt and 137 Caesium uptake by two freshwater bivalves during a brief field experiment.
C. Adam*, B. Fraysse*, J. Garnier-Laplace*, J. P. Baudin**, A. Boudou***
Bull. Environ. Contam. Toxicol. (2002), 68 : 428-435
In the framework of freshwater radioecology, numerous studies have been carried out on the contamintion of aquatic organisms by artificial radionuclides taken separately, whereas the bioaccumulation of radionuclides may be influenced by non-radioactive metals present at significant concentrations in many aquatic ecosystems. To our knowledge, the effect of the physiological disruption induced by these trace metals on radionuclide bioaccumulation by freshwater organisms has never been investigated. This multipollution context must be taken into consideration to improve the biomonitoring of the radioactive liquid wastes released by nuclear powe plants. The methodology for efficient monitoring includes the use of bioindicators, which alleviates a number of problems associated with the analysis of trace pollutants in water or sediments and gives a direct indication of their bioavailability to the biocenosis. The possible organisms for use as trace pollutant indicators include bivalve species, e.g. the Asiatic clam Corbicula fluminea and the zebra mussel Dreissena polymorpha. The two species are complementary, since their ecological specificities are different. C fluminea is a benthic species whereas D. polymorpha is an epilithic one.
The aim of this study was to examine the effects of a prior exposure, to waterborne cadmium and zinc, on the uptake of artificial radionuclides by C. fluminea and D. polymorpha. The metallic contamination site was located downstream from an old zinc ore treatment facility. This prior metallic contamination was followed by radionuclide in situ exposure of the bivalves at the nuclear power plant of Golfech (France), in an artificial channel.
* Laboratory of Experimental Radioecology, Institute of Radioprotection and Nuclear Safety, B. 186, BP 1, 13108 Saint Paul-Lez-Durance Cedex, France
** National Center of Scientific Research, Institute of Protection and Nuclear Safety, B. 186, BP 1, 13108 Saint Paul-Lez-Durance Cedex, France
*** Laboratory of Ecotoxicology, University of Bordeaux I/NCSR, Avenue des Facultés, 33405 Talence Cedex, France