Grütter, A.A.Grüttervon Gunten, Hans RudolfHans Rudolfvon GuntenRössler, E.E.Rössler2024-10-252024-10-251992https://boris-portal.unibe.ch/handle/20.500.12422/160856Drinking water is recovered in the alpine and peri-alpine regions to a large extent from shallow aquifers in unconsolidated deposits of quaternary glaciofluvial origin. Due to the importance of drinking water in the exposure pathway for many radionuclides we are studying sorption processes on samples from this aquifer and, in addition, on clay minerals. Here, we report on batch measurements of sorption, desorp-tion and exchange with barium in the concentration range of 1.0E-08 to 1.0E-04 Μ on glaciofluvial materials from Glattfelden, Switzerland, and on the clay minerals montmorillonite, illite and chlorite. For the aquifer material, the influence of grain size, mineralogy of the < 32-μηι size fraction and composition of the synthetic groundwater was investigated. The results suggest that reversible cation-exchange mechanisms on clay minerals are responsible for the sorption behaviour of barium on the glaciofluvial aquifer material. Its dependence on the composition of the groundwater was reproduced with a 3-site model based on ion-exchange. The sorption isotherm for the aquifer material resembles that of the clay minerals illite and chlorite, but deviates considerably from that of montmorillonite.enarticle10.7892/boris.11505010.1524/ract.1992.5859.2.259