Health Risk Analysis and Source Apportionment of Polyaromatic Hydrocarbons in Water and Sediment in Aluu River

Abstract

This study focuses on the health risk analysis and source apportionment of polyaromatic hydrocarbons in water and sediment in Aluu River. The objectives were to quantify and characterize PAH concentrations, determine the sources of these contaminants and the health risks associated with exposure to polycyclic aromatic hydrocarbons. Surface water and sediment samples were collected from multiple locations along the Aluu River using standard sampling protocols. PAHs were extracted and quantified using Gas Chromatography-Mass Spectrometry (GC-MS) methods. Source apportionment was conducted using principal component analysis (PCA), while ecological and human health risk assessments were performed using hazard quotient (HQ) and cancer risk (CR) models. PAHs were detected in both water and sediment, with total concentrations ranging from 3.33 to 6.41 µg/L in water and 22.33 to 31.00 µg/kg in sediments. High molecular weight PAHs (HPAHs) predominated, suggesting pyrogenic sources. Health risk assessments indicated elevated HQs for several carcinogenic PAHs such as chrysene, benzo[a]pyrene, and benzo[ghi]perylene. The total cancer risk from PAHs in surface water ranged from 0.039 to 0.090, significantly above the acceptable threshold (1.0 × 10⁻⁶), indicating potential long-term health concerns. Principal component analysis (PCA) identified distinct pollution sources for PAHs, including industrial discharge, combustion activities, and urban runoff. The findings demonstrate significant contamination of the Aluu River by PAHs, with sediment acting as a major sink for these pollutants. The dominance of high-risk carcinogenic PAHs, coupled with elevated health risk indices, indicates potential long-term ecological degradation and serious public health concerns for populations dependent on the river. Establishment of a long-term environmental monitoring program to track PAHs trends and evaluate effectiveness of mitigation strategies is recommended