Our researchers once thought that the Qinghai Tibet Plateau is relatively free from mercury pollution. However, a previous study on domestic sewage found that the total mercury emissions of domestic sewage in Tibet have reached the national peak, both in total and per capita.
Domestic sewage is closely related to people's daily life. The concentration of pollutants in it is high, and the pollution of relevant people is likely to be high. (in fact, this idea has enabled researchers to develop technology to detect toxic substances in sewage, and it has been used in actual drug control work.)
Until now, we have always believed that the food-borne mercury intake in China mainly comes from rice and fish. In this study, since we found the high concentration of domestic sewage in Tibet, we have a hunch that there will be new sources of mercury in Tibet. After all, on the one hand, the food types in Tibet are quite different from those in other regions (Tibetans have no habit of eating fish, even tend not to eat fish in religion; the consumption of rice is also far lower than that in other regions); on the other hand, due to the relatively backward industrial development compared with other regions in China, the industrial emissions of pollutants in Tibet are relatively small.
We found that the source of this mercury is Tibetan medicine.