The radiotracer method has been used for the analysis of speciation of pollutants in environmental samples, and for characterisation of the interaction of pollutants with humic substances and the solid phase in surface waters.
Application of the radiotracer method has facilitated the development of separating methylmercury and inorganic mercury from human hair. Speciation of cadmium in soil solutions was investigated with Cd-109 added to soil extracts and with electrophoresis, ultrafiltration and dialysis. The results corroborate that the radiotracer method enables us to avoid the shift of equilibria in solution caused by many invasive methods of speciation analysis.
The radiotracer method was used for the study of the complexation of cadmium, europium and uranium with humic substances in aqueous solutions. Special attention has been paid to the kinetics of dissociation of metal humate complexes, which can significantly affect environmental migration of metals and radionuclides. The kinetics has yet been studied with europium, simulating behaviour of tervalent actinoids. The effect of humic substances on the distribution of uranium and cadmium between clay and aqueous solution was investigated with the aim to elucidate the effect of humic substances on the migration of these contaminants in the environment and to examine potential application of clay-humate complex for treatment of waste waters.
Laboratory batch experiments were carried out where the distribution of Cs-137, Co-58 and Sr-85 between sediments and river water was measured. The results elucidated a mechanism of interaction of the radionuclides with sediments and indicated some factors to be considered in modelling the migration of radionuclides in rivers.
Part of this research was carried out in the framework of research programmes coordinated by the International Atomic Energy Agency. Some of the problems were studied in collaboration with Institut fuer Nukleare Entsorgungstechnik, Forschungszentrum Karlsruhe.