Distribution of radioactive 134Cs due to the Fukushima Dai-ichi Nuclear Power Plant accident was measured using a scintillation spectrometer in the mountainous areas of southern part of the Tohoku, northern and southern parts of Kanto and Koshin-etsu regions. As a result, intensity of radiation increased with decrease of altitude in Mt. Azuma and Mt. Yamizo, whereas intensity increased with increase of altitude in Mt. Gozen and Mt. Oyama. This indicates that plumes (polluted air masses) with their center at the specific height moved depending on the meteorological condition. Although radioactive 134Cs was not detected at Mt.Kaikoma, relatively intense γ-ray was observed due to radioactive 40K from granite.
To remove catechin from green-tea extracts, N-vinylacetamide (NVAA) as an amide monomer was graft-polymerized onto a commercially available nylon-6 fiber. The resultant NVAA-grafted fiber with a degree of grafting of 79％ exhibited a saturation capacity for catechin of 0.78 mmol/g of the fiber, which is 3.7-fold higher than that of N-vinyl-2-pyrrolidone-grafted fiber. The catechin adsorbed onto the NVAA-grafted fiber was quantitatively eluted with 0.1 M NaOH and the fiber was repeatedly used for catechin adsorption.
Low-sodium salt is produced to prevent over-consumption of salt by substituting potassium chloride (KCl) for 30 or 50 wt％ of sodium chloride (NaCl) in the usual salt produced from sea water. As 0.0117％ of naturally occurring potassium contains radioactive nuclide 40K, low-sodium salt emit radiation. Therefore, the compression and formation method was applied to fabricate disk-shaped natural radiation sources from the branded low-sodium salt (LSS-source), Yasashio (Ajinomoto Co., Inc.). Thus, 22 sources were fabricated and their weight, thickness, diameter, and 1-min counts were examined. Measurement tests on the three principles of radiation protection were performed to evaluate the practical suitability of the LSS-source for educational use. It was found that the individual differences of the 22 LSS-sources were very small. In addition, LSS-sources are useful educational radiation sources compared with KCl-natural radiation sources, and comprehensible results were obtained for LSS-sources more than for kelp-natural radiation sources.