Effect of metal ions in groundwater to radiocesium sorption into bentonite mineral from Tasikmalaya

Karawang and Sumedang areas were two of the preferred sites for radioactive waste disposal facilities in the future, and the effect of coexistence ions in their groundwater to radiocesium sorption in bentonite sample has been studied. Bentonite material is placed in the surrounding of disposal facility and usually is used as an engineered barrier to prevent the migration of radiocesium from the facility to the environment by sorption mechanism. The concentration of cation in groundwater such as K+, Na+, Ca2+ and Mg2+ have been obtained from the field work and could many folds higher when compared with the assumed radiocesium concentration releases to the environment. The existed cations in groundwater were predicted to be able affected to the radiocesium sorption into the bentonite sample. Coefficient of distribution (Kd) was used as the indicator of radiocesium sorption into bentonite sample. The result showed that increased in cation concentration in groundwater reduced the Kd value of radiocesium into bentonite samples up to 21 % compared with no cation exists condition in groundwater.