Chernobyl accident fallout and major radioactive water leaks from the damaged Fukushima Daiichi nuclear power plant arouse concerns regarding the potential radioactive contamination of aquatic systems nearby and set a necessity for a reliable risk assessment tool in case of accidental radioactive discharge in the environment. Determination of trace levels of environmental plutonium, typically at femtomolar concentration levels, and other tetravalent metals requires a thorough radiochemical separation and very sensitive analytical methods. DGT technique (Diffusive Gradient in Thin-films) is widely used for sampling trace metals in various media (water, pore-water of soils and sediments). It has been successfully applied for determining radioisotopes and radioelements (134Cs, 137Cs, U, etc.). For the moment, there is no specific DGT able to discriminate different tetravalent species (An4+) from di or trivalent transition metals. We propose to develop specific An4+ resins usable in various physico-chemical environments (water, pore-water of soils and sediments). For this purpose, it is mandatory to design and select the optimal chelators, which should exhibit very high binding affinity and selectivity towards the tetravalent elements at the pH values of natural waters, over all other metals. The chelator metal binding properties in solution will be characterized from a structural and thermodynamic point of view in order to assess their efficiency in terms of sensitivity and specificity. The next step will be to immobilize these ligands onto organic polymers to afford original chelating resins (i) for analytical separation and (ii) for hitherto unavailable DGT-type devices. The pre-concentration capacities of the analytical DGT tool will be validated with respect to Pu and other tetravalent metals in laboratory (lab tests) and real environmental conditions (field tests). Last but not least, the industrial partner is committed to produce and commercialize the various resins and DGTs.
Principal Investigator: Dr Michel Meyer