Abstract
The seasonal variations of gross counts of the radioactive substances in fall-out deposited on leaf-vegetables, rinsed vegetables and that in milk were previously reported by the author. This report deals with additional foodstuffs such as short-necked clam, fruits and other standard foods recommended by the National Laboratory of Dietics for normal adult Japanese. The following results were obtained;
(1) Gross counts of the radioactive substances in fall-out deposited on leaf-vegetables decreased continuously since November in 1961 and about a-thousandth of its count were observed in 1965.
(2) Gross counts of the radioactive substances in fall-outs on leaf-vegetables and that contained in vegetable itself varied seasonally, i.e., increased in winter, decreased gradually untill autumn and then increased again in winter.
(3) Remarkable seasonal variations on the gross counts of radioactive substances in raw milk and pasteurized milk were not observed, but a little lower counts were observed in Jan. and Feb.
(4) Higher gross counts of radio active substances were observed in perennial fruits, such as pear and grape in comparison with water melon and the annual fruits.
(5) Gross counts of the radio active substances in shortnecked clam increased in May and June, but the value decreased gradually untill winter and were observed the lowest value in Jan. and Feb.
(6) The different value of radio activity in each standard foodstuffs was observed between 1958 and 1959. But the total value of each year was almost the same.
(7) The 137Cs was found in all materials by a nuclear analysis of radio active substances.
