THE PRESENT PROPOSAL AIMS TO ENLARGE THE ACTUAL KNOWLEDGE ON THE ECO-PHYSIOLOGY OF TRANSURANIUM ELEMENTS. SPECIFIC ATTENTION IS CENTERED AROUND DATA NEEDED FOR MODELLING PURPOSES. THEREFORE A STUDY ON TRANSURANIC (AMERICIUM AND CURIUM) ACCUMULATION AND TURNOVER IN FRESHWATER ORGANISMS UNDER DIFFERENT ENVIRONMENTAL AND PHYSIOLOGICAL CONDITIONS IS PROPOSED. THIS RESEARCH WILL BE CARRIED OUT IN CLOSE COOPERATION WITH SIMILAR RESEARCH ON ESTUARINE AND MARINE ORGANISMS. COOPERATION THAT SUCCESSFULLY STARTED IN THE FOREGOING CEC CONTRACT.
The claim that microbial activity can profoundly change the behaviour of americium-241 and curium-244 in sediments and water cannot be demonstrated for either of the 2 isotopes in coarse sandy sediments. For sediments with a higher silt, and particularly a higher clay content, however, larger differences in adsorption are obtained, up to 6 times more in the nonsterile than in sterile sediments. Bioavailability is not seriously influenced by microbial activity. Gamarus pulex fixes quite similar quantities of both transuranics under sterile and nonsterile conditions. The concentration factors of americium-241 were in these experiments about 1 order of magnitude higher than for curium-244. The data demonstrate how experimental values are to be used with caution in modelling and risk assessment studies.
1. BIOLOGICAL AVAILABILITY OF TRANSURANICS IN AQUATIC ECOSYSTEMS
2. SPECIATION OF TRANSURANICS IN AQUATIC ENVIRONMENTS