Distribution, source apportionment, and assessment of heavy metal pollution in the Yellow River Basin, Northwestern China

The Ningxia region in Northwest China, a significant grain-producing area, heavily relies on the Yellow River for agricultural irrigation. Maintaining the ecological health of the Yellow River is crucial due to its role as the primary water source. This research comprehensively assessed heavy metal (HM) levels in surface water and sediments within the Ningxia section of the Yellow River basin. It specifically examined the concentrations of Sr, Zn, Mn, Cu, As, Cd, Cr, Co, Sb, Pb, Tl, Ni, and Hg, detailing their spatial distribution and associated risks. Sources of pollution were identified, and their relationships were explored using statistical analysis and positive matrix factorization (PMF). The risk assessment results indicated elevated pollution levels of Tl and slight pollution of Hg in surface water. Integrated Nemerow Pollution Index (PN) calculations revealed that 18% and 20% of surface water samples exhibited pollution during the wet and dry seasons, respectively. In sediments, mean concentrations of Mn, As, Ni, Cr, Zn, Cu, Cd, Sr, Co, Sb, and Tl exceeded background levels, with Mn being the highest. Sediments exhibited low to moderate HM pollution, with higher concentrations found in northern Ningxia’s irrigated areas. Major sources of HM pollution included agriculture, traffic emissions, and natural sources. Overall, this study provides essential data to improve water resource management and mitigate HM pollution in the Ningxia section of the Yellow River Basin. © Higher Education Press 2025.