Efficacies of manganese chloride and Ca-DTPA (calcium diethylenetriaminepentaacetic acid) for the elimination of incorporated 54Mn were investigated in mice. Each mouse was given an intraperitoneal injection of 54Mn and initial whole-body radioactivity was measured immediately. Manganese chloride (10mg-Mn/kg) or Ca-DTPA (10 or 100mg/kg) was injected intraperitoneally once or repeatedly at various times after 54Mn injection. Efficacies for elimination were estimated by measuring the whole-body retention of 54Mn for 14 or 21 days. A single injection of manganese chloride eliminated more than 80% of the incorporated 54Mn when it was injected within 24h after the injection of 54Mn. Although the efficacy was decreased with the passage of time after the injection of 54Mn, about 50% was still eliminated after 14 days. Repeated injection of this agent raised the efficacy, but the second or later injection was less effective than the first injection. Ca-DTPA eliminated the incorporated 54Mn by 57% for 100mg/kg and by 19% for 10mg/kg when it was injected after 3h. But after 6h or later, Ca-DTPA had little efficacy. These results indicate that manganese chloride is very effective to eliminate the 54Mn from accidentally contaminated persons and the efficacy of Ca-DTPA is less than that of manganese chloride.
Transfer factor (Tf) is empirically obtained as the ratio of radionuclide concentration in plant edible part and that in soil. Because of its simplicity, Tf is widely used in dose estimation of human exposure. However, since Tf concept has not sufficient physical meaning, the estimated results have uncertainty. In practice, large variation range is seen in the Tf values reported in literatures. The method for deceasing the uncertainty should be developed. In the present study, Tf values of cesium (Tf-Cs) reported in a literature were statistically analyzed according to classification variables. Some statistical values (geometric mean, minimum, maximum, percentile values) were shown and the effect of classification on decrease of the uncertainty was evaluated. The following information were obtained; (1) The geometric mean of Tf-Cs obtained from field was greater than that from lysimeter- and pot-experiment. (2) The geometric mean of Tf-Cs obtained in sand was greater than that in loam. (3) Tf-Cs variation in sand were greater than those in loam. Then the uncertainty of Tf-Cs is expected to be decreased in loamy soil. (4) Correlation between soil-pH and Tf-Cs was small. Then soil-pH is not effective information for the decrease of Tf-Cs uncertainty.