Abstract: The concentrations of 14 heavy metals in sediments and surrounding soils of major rivers in the source region of the Yangtze River were detected by using inductively coupled plasma mass spectrometry and atomic fluorescence spectrophotometer. The accumulation of heavy metals was evaluated by enrichment factor method, and the distribution characteristics and sources of heavy metals were also analyzed. Results unraveled that except for Ni, Pb, Cd, and Hg, all other heavy metals in river sediments were lower than the background values of sediments in China; however, Hg, Ni, and Cd were enriched in sediments. Compared with other rivers in the source region, Tuotuo River suffered from a relatively high concentration of Cd, Tongtian River was subjected to high concentrations of Hg and Fe, while Chumar River boasted a low concentration of all heavy metals. The heavy metals in sediments were mainly affected by natural factors. In terms of bank soils, the concentrations of Ni, Pb, Cd, and Ti were slightly higher than the background values of soils in Qinghai Province, yet with light enrichment.Compared with the soils along other rivers in the source region, the bank soil along Dangqu River had high concentrations of Cr, Ni, and Cu, and Tuotuo River Pb, Cd, Sb, and Tl, whereas Tongtian River saw a high concentration of V. The heavy metals in bank soils along rivers were mainly affected by natural factors, and also some affected by traffic factors. The research achievements offer fundamental support for the eco-environmental protection in the source region of the Yangtze River.

Key words: source region of Yangtze River, heavy metals, distribution characteristics, enrichment factor method, influence factors, surface sediment, bank soil