Spatial Distribution and Risk Assessment of Heavy Metals in Ziya River Basin

This study examines the spatial distribution and ecological risks of heavy metals (Hg, Pb, Zn, Cu, Cd) in wetlands and rivers of China’s Ziya River Basin. Sampling in 2017–2018 covered key wetlands (Nandagang, Beidagang) and rivers (Fuyang River, Ziya New River). Water, sediment, and zooplankton were analyzed via ICP-MS and standard methods. Results showed spatial variability: riverine Hg (441.7 ± 1354.1 ng·L −1 ) exceeded standards by fourfold, while Dongwushi Reservoir’s high Pb (53.1 ± 33.9 μg·L −1 ) linked to mining. Nandagang’s Hg (88.3 ± 109.6 ng·L −1 ) correlated with historical contamination. Cu, Cd, and Pb indicated anthropogenic sources (urban/agricultural runoff), whereas Zn and Hg tied to fertilizers and atmospheric deposition. Despite localized risks, comprehensive indices (I ≤ 1) showed no basin-wide pollution. Findings emphasize targeted control for hotspots and support wetland conservation.