Distribution characteristics, enrichment patterns and health risk assessment of dissolved trace elements in river water in the source region of the Yangtze River

The security of water environment in the source region of the Yangtze River (SRYR) is also vital to the water environment security of the whole basin. The results showed that the rivers in the SRYR were weakly alkaline and the values of total solid solubility (TDS), electrical conductivity (EC), turbidity concentration and salinity were higher than the values in the middle and lower reaches of the Yangtze River. The results showed that the dissolved trace elements detected displayed obvious regional distribution characteristics, showing a concentration trend of high in the Chumar River, low in the Dangqu, and middle in Tong River. All water quality indexes in the SRYR met the surface water environmental quality standard of class II based on GB 3838-2002 except Hg, while the average concentration of As exceeded 10 mu g/L. The main enrichment elements in the SRYR were Li, Se, As and Pb, and their concentrations were far higher than the average concentration of the world rivers. Moreover, the HI and HQ(ingrstion) of children caused by As in the SRYR were greater than 1. This study could provide basic data for water environment protection and water resource management in the SRYR.