SIMPLIFIED AND SENSITIVE ANALYSIS OF ORGANICALLY BOUND TRITIUM IN TREE RINGS TO RETROSPECT ENVIRONMENTAL TRITIUM LEVELS

摘要

In order to estimate the environmental tritium level retrospectively, the authors tried to establish a simplified and sensitive method for determination of organically bound tritium in tree rings. Organically bound tritium as low as approx. 1 Bq L(-1) was determined with sufficient reproducibility, after combusting 25 g of dried wood without isolating cellulose. In Japan, this tree ring analysis reproduced the historical fallout tritium levels during 1961-87 in the general environment and detected a probable local effect of tritium discharge from nuclear facilities retrospectively.