Levels of artificial radionuclides and uranium in rain water collected from Ibaraki (Japan) following the Tomsk-7 accident in Russia

Abstract

Measurements of some selected radionuclides were carried out in rain waters collected from Ibaraki Prefecture, Japan, following the nuclear accident at Tomsk-7, Russian Federation, in April 1993. The concentrations obtained for artificial radionuclides were⁹⁰Sr≦1.8 mBq l⁻¹,¹³⁷Cs≦0.1 Bq l⁻¹,¹³¹I≦0.1 Bq l⁻¹ and¹²⁹I≦4 μBq l⁻¹. Uranium (²³⁸U) concentrations in rainfalls in April 1993 were 6.3–39 ng l⁻¹. These data were compared to control values obtained previously and there was no appreciable influence on the radioactivity levels in Japan after the Tomsk-7 accident. Since only limited data on the concentrations of¹²⁹I and uranium in rain water are available, these new analytical results contribute to understanding the background levels for these nuclides.