Abstract: To reveal the hydrochemical composition and the distribution of heavy metals in the surface water of typical inland rivers in Qinghai, water samples were collected from the Bayin River, Golmud River and Xiao Qaidam Lake during July-August 2015. The concentrations ofmajor ions and twelve heavy metal elements were analyzed, and the water quality was assessed. The results showed that the chemical composition of surface water in rivers and lakes were primarily dominated by the rock weathering and evaporation crystalization processes, respectively. The concentrations of most heavy metals in lakes were higher than those in rivers, due to the enrichment and crystallization of heavy metals caused by lake water chemistry and evaporation. Principal component analyses (PCA) showed that the heavy metals mainly came from rock weathering and were less affected by human activities. The concentrations of heavy metals in river waters met grade I water quality according to the standard of Surface Water Environmental Quality Standard of China (GB 3838-2002).

Key words: fertilizer of calcium silicon magnesium potassium (CSMP), soil improvement, exchangeable base cations, soil pH, soil available silicon