TRITIUM CONCENTRATIONS OF BLOOD-SAMPLES COLLECTED THROUGHOUT JAPAN

Tritium concentrations were measured for blood samples collected from 20 cities throughout Japan during 1989-1990. The mean JH concentration was found to be 1.4 +/- 0.4 Bq L(-1) and 1.0 +/- 0.4 Bq L(-1) (combus tion water) for free water H-3 and organically-bound H-3, respectively , excluding the abnormally high data of one city. The organically-boun d H-3 contents clearly depended on the latitudes of sampling locations , although the free water H-3 concentrations showed no correlation wit h the latitudes. Organically-bound H-3 is considered to be more suitab le than free water H-3 as an indicator of long time H-3 exposure to hu man.