Pollution assessment and apportionment of toxic elements within urban riverine: Economic implications for rehabilitation

To combat rampant pollution, it is vital to implement approaches that quantify the contributions of various sources to the overall pollution levels, which could enhance comprehension of environmental impacts and formulate effective pollution control strategies. The study implemented an effective strategy to identify pollution sources, assess sediment quality and evaluate potential ecological risks. The sediment and water samples were collected from nine sampling points and subsequently analysed for total concentrations, yielding the following ranges: iron (Fe) 8200 – 32167 mg/kg, lead (Pb) 13.9 – 130 mg/kg, uranium (U) 3.91 – 6.92 mg/kg, thorium (Th) 2.93 – 5.50 mg/kg, arsenic (As) 0.66 – 9.93 mg/kg, cadmium (Cd) <0.01 – 0.3 mg/kg, and mercury (Hg) <0.01 – 160 μg/kg. The quantities of toxic elements in water were determined as U (0.08 – 1.35 µg/L), As (97.2 – 114 µg/L), Th (0.01 – 0.48 µg/L), Hg (0.01 – 0.39 µg/L), and Fe (0.09 – 1.37 mg/L) and Cd (0.01 – 0.27 µg/L). The ecological risk index demonstrated low and moderate potential index risk, with the pollution index revealing very high and moderate contamination factors for Pb and U, respectively. A combination of Principal Component Analysis and Positive Matrix Factorization employed for potential source identification revealed atmospheric disposition, gold mining activities, domestic and urban activities waste, agricultural practices, and unidentifiable sources with contributions of 23.9%, 19.0%, 18.7%, 8.1% and 8.0%, respectively. The economic advantages of river pollution rehabilitation mandate a balance between ecological integrity and socio-economic constraints to ensure an integrated approach to water management. To reduce long-term health effects, policies should address exposure thresholds and river pollution prevention strategies.