Concentration of fallout plutonium in environments

not registered; not registered; not registered; Ishimori, Yuu  

Most of plutonium isotopes resulting from nuclear weapons tests from 1945 through 1980 accumlated in environments because or their long half-lives. This report is a summary on the environmental fallout of plutonium concentration data obtained in Japan. Pu levels are as follows: (1)annual deposition (in recent 5 years; 1988-1992), from 0.004 to 0.02 Bq/m; (2)surface air (in recent 5 years; 1988-1992), less than the detectable limit; but only in Fukui prefecture, 22.910 mBq/m in 1988; (3)surface soil, usually, from about 0.1 to a few Bq/kg dry; from 3.3 to 12.3 Bq/kg dry at Okuetsu in Fukui prefecture where it is a typical mountainous area on the side of the Sea of Japan; and from 10.4 to 55.5 Bq/kg dry at Nishiyama district in Nagasaki city where the atomic bomb exploded; (4)river water, from 0.0008 to 0.059 mBq/l; (5)lake sediments, from 0.43 Lo 8.0 Bq/kg dry; (6)river sediments, from less than the detectable limit to 0.27 Bq/kg dry; (7)sea water, from less than the detectable limit to 0.084 mBq/l; (8)sea sediments, from less than the detectable limit to 7.25 Bq/kg dry. Pu/Pu activity ratio is about 0.04 (from 0.01 to 0.07 observed usually).