C. Dose Estimation from Residual and Fallout Radioactivity 3. Fallout in the Nagasaki —Nishiyama District—

Review of Thirty Years Study of Hiroshima and Nagasaki Atomic Bomb Survivors I. DOSIMETRY

Abstract

Fallout from the Nagasaki atomic bomb was mainly concentrated in the Nishiyama district of Nagasaki. Studies conducted in 1945 and 1946 indicated the average dose due to the external irradiation from fallout in Nishiyama to be as high as 30 to 130 R. A significant leucocytosis occurred among Nishiyama residents two months following the explosion. In the present 1969-1972 investigation, Nishiyama residents and appropriate comparison residents elsewhere in Nagasaki underwent comprehensive clinical evaluations including thyroid function and chromosome studies, radiochemical urinalysis and whole body counting. No clinical abnormalities were found among the Nishiyama residents, but whole body counting demonstrated significantly elevated ¹³⁷Cs concentrations with parallel results by radiochemical urinalysis. Increased ¹³⁷Cs contents of soil and agricultural products of the Nishiyama area were apparently responsible for the relatively high body burdens. The annual internal doses from ¹³⁷Cs in the Nishiyama district were estimated to be 0.292 mrad per year for males and 0.187 mrad for females.