Abstract: The selenium contents in the soil, food, and children’s hair samples collected from Kashin-Beck disease (KBD) and non-KBD areas in Tibet were deter mined to approach the relationship between the distribution of KBD and the selenium content in soil-plant-animal (human being) ecosystem in Tibet. The results showed that in Tibet, there was an overall low level of selenium. The selenium content in the samples collected from KBD areas was significantly lower than that in non-KBD areas (P<0.05). The low soil selenium content in KBD areas was the critical reason leading to the low selenium level in grain and human bodies in these areas, and the KBD prevalence in Tibet. Therefore, to improve soil environment and to increase soil selenium content would be the critical way to prevent the KBD prevalence in Tibet. Moreover, selenium supplement could obviously improve the selenium content of children’s hair, and prevent and control KBD effectively. However, this supplement should be insisted on longtime.

Key words: Soil organic matter, ¹⁴C, Carbon cycling, Subtropical zone, Dinghushan Biosphere Reserve