@misc{oai:repo.qst.go.jp:00080348,
 author = {N.Kavasi and Y.Omori and A.Sorimachi and T.Aono and K.Shozugawa and M.Hori and S.K.Sahoo and Kavasi, Norbert and Aono, Tatsuo and Sahoo, Sarata},
 month = {Aug},
 note = {The main contaminants released from the Fukushima Daiichi Nuclear Power Station accident is the volatile radioisotopes of caesium (137Cs ~15 PBq, 134Cs ~15 PBq) with the non-volatile 90Sr (~0.14 PBq). The 90Sr (T1/2 = 28.8 y) is a pure beta particle emitter artificial radionuclide, produced by the fission of U and Pu isotopes. Low level (some Bq kg-1 or mBq kg-1) 90Sr contamination exists in different environmental matrices as a result of nuclear weapon tests and nuclear accidents. 
For the public, radiation dose resulted from external beta particles exposure is not relevant because the low penetration efficiency of beta particles and limited radionuclide deposition on human skin. However, radiation dose due to beta emitter radionuclide incorporation via ingestion and inhalation into human body must be considered in case of a nuclear accident. Basically, Sr element has no biological role in the human body, however it is an alkaline earth metal with similar bio-chemical properties of calcium thus can attach into the bone structure causing long-term radiation dose. From the view point of public health and natural radiation protection, 90Sr monitoring in various environmental, samples is essential.
In this work 90Sr contamination was determined in well and ground water samples collected from the Fukushima exclusion zone using a multi-collector thermal ionization mass spectrometry instrument equipped with wide aperture retardation potential (WARP) energy filter and Daly ion-counter. 90Sr could not detected in the water samples since the concentration of the 90Sr was below 30 mBq kg-1 (minimum detectable activity concentration). Considering the radiation protection of the population, the radiation dose from 90Sr ingestion is negligible., VII. Terrestrial Radioisotopes in Environment International Conference on Environmental Protection, 10-13 AUGUST, 2020 (TREICEP 2020)},
 title = {Sr-90 analysis in Fukushima water samples},
 year = {2020}
}