Total Ground Deposition of Strontium-90 in Japan (1)

Abstract

In view of the discrepancies between some data of the soil analysis, and the accumulated deposition of ⁹⁰Sr (1) technical errors in the analysis and (2) sampling errors due to the horizontal surface distribution were examined. The NaOH-HCl leach method was found the best among the conventional substitutes for the standard fusion method and an interlaboratory comparison also probed the applicability of this method as a standard. A study was made how to obtain a representative sample from an area of 1000 m² of particular location. Statistical analysis of data obtained from undisturbed, rice and wheat-field suggested that to get a confidential limit of 10% at least 10, 4 and 8 cores, respectively, should be taken for making a composite sample. A preliminary study on the vertical distribution was also made in undisturbed soils. The amount in the upper 10 cm layer was 81.3% on the average of the total to the depth of 30-50 cm in different soil profiles.