Distribution of Heavy Metals in the Upstream of Yellow River and Ecological Risk Assessment

14 sampling sections in the upstream of Yellow River were selected to detect concentrations of As, Zn, Cu, Cr, Pb and Cd, followed by ecological risk assessment. The metal content in water ranged among ND to 5.496 µg/L, while ND to 1097.995 µg/g in suspended solids (SS) and ND to 75.524 µg/g in sediment. NMDS results proved that metal contents in water displayed significant difference in spatial scale, while that in SS and sediments were remarkably diverse in different season. Correlation analysis proved that Zn, Cu, Cr and Pb were mainly from natural process, while As and Cd were partially from man-made pollution. Meanwhile, establishment and operation of reservoirs also impacted metal distributions, which could be the combined actions of interception to SS by big dams, dilution by impounding, and distribution effect in mud-water interface. Results by potential ecological risk index proved that heavy metals in the upstream of Yellow River showed low risk, and Cd and As played the important role. © 2021 Peking University.