Selenium-poor regions in China could be the result of monsoon activity, according to an article published in Nature Communications. This finding could lead to predictions of terrestrial selenium distributions, which may help prevent health hazards, such as chronic bone, cartilage and heart disorders, that are related to selenium deficiency.

Selenium deficiency is a major problem globally, with up to one billion people suffering from low selenium intake. The problem is particularly noticeable in central China, where many young women and children suffer from Kashin-Beck disease, affecting bone and causing joint pain, and the potentially-fatal Keshan disease, which affects the heart. However, the cause of these selenium-poor areas remains unknown.

Lenny Winkel and colleagues analyse climate records from central China, covering almost seven million years, and show that changes in selenium concentrations over time could be related to the intensity of the East Asian monsoon. The team propose that high concentrations of selenium are transported from the oceans via the atmosphere and are deposited by rainfall during the summer monsoon.

Although bedrock geology can explain localised areas with high soil selenium concentrations, the similarity between selenium distribution and rainfall intensity, south of the summer-monsoon limit, identified by the team is significant. Further work is needed to confirm the team’s hypothesis that this is caused by the monsoon rains.