Tritium concentration in monthly precipitation in Okinawa and Kagoshima, southern Japan

Abstract

This study aimed at understanding the background concentration level of tritium in precipitation in southern Japan, where precipitation samples were collected monthly in 2022 in Okinawa and Kagoshima. Tritium concentration in monthly precipitation collected in Okinawa since 2014 ranged from 0.05 to 0.39 Bq per L with the mean value (2015-2022) of 0.15 ± 0.06 Bq per L. That of Kagoshima since 2022 ranged from < 0.11 to 0.58 Bq per L with the mean value of 0.30 ± 0.13 Bq per L. Our observed values were summarized with reported values, from which a clear latitude effect for tritium concentration was found in precipitation of southern Japan.