Elimination of137Cs from highly accumulated trefoil (leaf and stem) through boiling in distilled and salted water were investigated in relation to study the effect of cooking and processing on biochemical states of radionuclides (RI) contaminat-ing in foods. (1) 137Cs was hardly eliminated from the trefoil immersed in a distilled water at room temperature (about 15°C) during 10 min. (2) 137Cs was considerably eliminated from the trefoil when boiled in a distilled water, 0.3-3.0% salt concentration of the water and soy sauce: about 40-60% (after 2 min), 70-85% (5 min) and 80-90% (10 min), respectively. (3) Elimination of137Cs in the soy sauce (e.g. 77.0±2.9%, at 1% salt concentration after 10 min) was restrictive comparing to that in the salt water (93.4±2.3%) . These results are expected to contribute to evaluate the radiation exposure to man when a boiled trefoil contaminating with 137Cs was ingested.
An radioactivity monitor for waste solution has been constructed using a liquid scintillation technique, which enables beta-emitter mixture to be analytically radioassayed. The method of least squ-ares has been applied to the radioassay for relatively low-level beta-emitter mixture in radioactive waste solution. This system can get rid of the difficulty of analysis for beta-emitter mixture in a mon-itoring sample, and provides fundamental information for subsequent waste-treatment. Detection limit of five nuclides was estimated to be about 0.02 Bq/cm3, which is sufficiently low compared with the values of authorized safety guideline.