ABSTRACT:The Tsunami due to the Great East Japan Earthquake on March 11, 2011 indirectly caused a nuclear disaster at the Fukushima Daiichi nuclear energy plant of the Tokyo Electric Power Company. The radioactive strontium dispersed by the accident has spread to the soil, lake, river and marine environments. In addition, contaminated groundwater continues to be generated by the flow under the damaged facilities of the plant. The increase of collected tainted water makes it difficult to secure the storage facility. In the face of such situation, the decontamination work for the radioactive strontium has not been completed. It is possible that humans may be exposed as a result of transfer through the food chain and biomagnification when the tainted water, including the major quantity of strontium leak to the marine environment. Therefore, the decontamination of strontium is an urgent requirement. To help address this risk, we previously conducted an experiment to sequester strontium into an adsorbent so as to decrease the degree of contamination. The results of this earlier study confirmed that the uptake ability of adsorbent for strontium varied in different solutions. In this study, the adsorption test of adsorbent is conducted to understand its ability in solution composed of magnesium, potassium or chloride. The hydroxyapatite derived from fish bones is developed and used as the adsorbent. From the result of tests, it is confirmed that the adsorption ability of the hydroxyapatite for divalent cation is high in the various solutions.