Ecological and health risk assessment based on source apportionment of heavy metals in the River Jhelum: a landscape-scale analysis

This study comprehensively investigated the spatial distribution, source identification, and ecological and human-health implications of heavy metal (HM) contamination in the River Jhelum, Pakistan. Sixty sampling locations were analyzed for heavy metals concentrations. Concentrations of Zn, Cu, and Fe reached 3,365 µg/L, 1,910 µg/L, and 1,185 µg/L, respectively, whereas Cd remained comparatively low (0.5–15 µg/L), indicating localized contamination peaks. Descriptive statistics showed significant variation, particularly for Cu and Zn, reflecting sporadic contamination events. Spatial analysis revealed the highest Fe and Zn levels in downstream industrial zones, whereas Cd remained the lowest across the basin. Pollution indices, including the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), and Potential Ecological Risk Index (PERI), identified localized zones of elevated contamination and ecological concern, especially downstream. However, overall conditions ranged from moderate to high risk. Principal component analysis (PCA) and positive matrix factorization (PMF) indicated contributions from industrial/urban, agricultural, and geogenic sources. The health-risk assessment showed HI values below 1.0 for both adults and children, with slightly greater vulnerability in children. This study provides a comprehensive integrated assessment framework for evaluating heavy metal contamination in transboundary river systems, linking geological sources, landscape-scale patterns, and ecological-health risks to support evidence-based sustainable water resource management.