Spatial-temporal analysis and background value determination of molybdenum concentration in basins with high molybdenum geochemical background - A case study of the upper Yi River basin

The environmental background value of the river section is important. It can be used to evaluate the effect of pollution control of the upstream of that river section, analyze the trend of environmental pollution, and assist the government to make decisions. Yi river is the main tributary of the Yellow River. In the headwaters of the Yi river, there are two very large molybdenum mines with a history of mining and smelting of many years. This area is also a region with a high molybdenum geochemical background.