Accumulation of mercury in excavated bones of two natives in Japan.

Mercury content of excavated bones and surrounding soil was compared between the two areas of Shikoku, Tokushima and Matsuyama. Results show a high variance of mercury content between localities and between ages of the burials. There was a high mercury occurrence in the 6-7th century in Tokushima and a moderate one in Matsuyama, and a trace in the 12-17th century in both places. Moreover, a low level of mercury was observed in the soil samples of Tokushima, and mercury was not detected in any of the Matsuyama soil samples. Therefore, these occasions of high mercury content may be due to artificial uptake, and may relate to differences in conventions and customs.