Laser-induced optical spectroscopy for the speciation of f-elements in natural aquatic systems

For the R + D work of this project, the aquifer system of the Gorleben site was the counterpart selected for the comparative analysis verifying the applicability of the laboratory data on the solubility and sorption of radionuclides in an aquatic system. The progress report in hand deals with spectroscopic studies of the complex-forming behaviour of trivalent Cm, Eu, and Am, and with the spectroscopic quantification of the uranyl ions in aquatic solutions and ground waters. The experiments were carried out using modern, sensitive laser spectroscopy, i.e. techniques such as time-resolved, laser-induced fluorescence spectroscopy (TRLFS) and laser-induced photoacoustic spectroscopy (LPAS), which at the same time were tested and found suitable for analysing the chemical reactions of the elements under natural aquatic conditions for the concentrations ranging from 1x10-6 to 1x10-12 mol L-1. In addition, a method was developed and tested allowing a quantitative deterination of ground water colloids by means of photoacoustic measurement of light scattering (PALS). (orig.)