Radioactivity surveillance data for the environment around Ningyo Toge Works (1997)

Radioactivity level of the environment around Ningyo Toge Works and the ruins of uranium mine has been periodically determined for the purpose of keeping the favorable natural environment. Periodical measurements for plutonium levels around the Works and the control site are also carried out as the use of recycled uranium. As the measuring sites, ten sites in the Works and 22 sites outside were chosen. Various samples from the air, land water, soil, plants, etc. were periodically collected 1-4 times per year for analyzing radioisotopes and fluorine and the data were all reported to Okayama prefectural office. The spacial γ-ray dose level and the levels of 238U and 226Ra in airborne dusts,river water, river sediments and paddy soil were lower than the respective desired levels. Furthermore, the plutonium levels in the river sediments and uncultivated soil collected from those sites were similar to the levels detected in other domestic regions. (M.N.)