Leakage of gaseous125I from the various kinds of plastic film bags packing Na125I solution was determined. The polyethylene bag was permeable to the gaseous125I and active charcoal could not prevent the leakage. The laminated plastic bags composed of polyethylene terephthalate and polyethylene was slightly permeable, and the leakage decreased either in the presence of active charcoal or with the use of doubly packed bags. Leakage of125I from the various kinds of container for the Na125I solution was also determined.
Background radioactivity levels in Niigata city area were studied through the years of 1981-1984. As the results, it was found that the gross β-radioactivity in underground (well) water samples were comparatively higher than those of other ground water samples. Ion chromatographic and γ-ray spectroscopic determination revealed that this higher radioactivities were contributed by40K rather than radium or thorium series nuclides or fallout originated90Sr.