Concentration of natural radioactive nuclide (Pb-214 and Bi-214) in foods from Yamanashi

Abstract

The concentrations of Pb-214 and Bi-214 in groundwaters and agricultural products from several geologically distinct parts of the Yamanashi region of Japan were measured and compared. The concentrations of Pb-214 and Bi-214 in groundwaters were well correlated with each other, and were consistent with the predominant geology in each area. The concentrations of both radionuclides in agricultural products were much lower than the levels in groundwaters, and did not appear to be related to local geology or habitat. Freshwater fish showed higher levels than agricultural products, though the levels were lower than those in groundwaters. Unexpectedly, wild mushrooms (but not cultivated mushrooms) showed relatively high levels of Bi-214, though their levels of Pb-214 were undetectable. Based on the levels of Pb-214 and Bi-214 detected here, annual internal radiation exposure of humans from these sources is considered to be extremely low.