POLYCYCLIC AROMATIC HYDROCARBON (PAHS) CONTAMINATION IN TEGUERE RIVER, KORHOGO, NORTHERN CÔTE D’IVOIRE: CONTAMINATION LEVELS, PROBABLE SOURCES AND ENVIRONMENTAL IMPLICATIONS

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic contaminants that pose significant environmental and public health. The objective of this study was to assess the risks associated with the presence of polycyclic aromatic hydrocarbons (PAHs) in the Teguere River. Ten water samples were collected from upstream and downstream locations and analyzed for the 16 priority PAHs using high-performance liquid chromatography (HPLC). Eight PAHs were quantified, while the remaining compounds were below detection limits. The mean concentrations of Σ8 PAHs were 0.3320 µg/L upstream and 0.3188 µg/L downstream, with low-molecular-weight PAHs constituting the dominant fraction. Phenanthrene was the predominant PAH upstream (0.0680 µg/L), whereas naphthalene was most abundant downstream (0.0620 µg/L). According to the SEQ-Eau V2 classification, the quantified PAHs indicated water quality ranging from very good to moderate. Diagnostic ratios, including Flt/(Pyr + Flt), Flt/Pyr, and LMW/HMW, indicated mixed pyrogenic and petrogenic sources. The non-carcinogenic hazard indices associated with dermal exposure were substantially below 1 for both adults and children, suggesting no appreciable non-carcinogenic risk under the exposure assumptions considered. However, the estimated total dermal cancer risks ranged from 2.16 × 10⁻³ to 3.91 × 10⁻³, exceeding the commonly accepted risk range of 10⁻⁶ to 10⁻⁴. Benzo[a]pyrene and benzo(b)fluoranthene were the primary contributors to carcinogenic risk. The total toxic equivalent quotient (TEQ) was 0.009904 µg/L upstream and 0.010123 µg/L downstream, while the mutagenic equivalent quotient (MEQ) was 0.013895 and 0.015176 µg/L, respectively. Regular PAH monitoring and reduced anthropogenic inputs are needed to limit dermal exposure, particularly among children.