Department of Environmental Management and Toxicology,

This study assessed the health risk assessment of surface water from Orhionmwon River, Southern Nigeria. A total of 18 water samples were collected at each location from May 2025 to July 2025. From upstream to downstream, water samples were taken from three locations in accordance with normal guidelines. While certain heavy metals were identified using the method of the association of analytical chemistry, the physicochemical properties of surface water were analysed using normal laboratory procedures. The average mean concentration of physicochemical and heavy metal properties in surface water were 30.12±0.20 (temperature), 6.97±0.13 (pH), 20.00±1.20 (EC), 9.89±0.51 (TDS), 4.50±0.17 (TSS), 14.39±0.48 (TS), 6.38±0.27 (turbidity), 5.76±0.59 (alkalinity), 4.84±0.32 (DO), 3.71±0.08 (BOD), 33.78±11.04 (COD), 6.61±0.78 (chloride), 7.61±2.34 (NO3), 0.47±0.25 (PO4), 1.84±0.19
(SO4), 6.92±0.31 (hardness), 1.80±0.16 (Ca), 0.63±0.10 (Mg), 0.87±0.06 (Na), 1.50±0.08 (K), 1.24±0.08 (Fe), 0.11±0.01 (Cu), 0.61±0.08 (Zn), 0.06±0.01 (Pb), 0.28±0.08 (Mn), 0.05±0.01
(Cr) and 3.96±0.15 (THC) respectively. Cadmium was not detected in the surface water from Orhionmwon River. The summative water quality index (WQI) for the three sampled stations were classified Grade E indicating that the water from Orhionmwon River is unsuitable for drinking (>100). The comprehensive pollution index across the sampled stations were classified as slightly polluted. Non-carcinogenic target hazard quotients (THQs) for oral exposure for the heavy metals were < 1.0 except for THC across the sampled stations, which suggests that consumers of water from these locations may be at high risk of non- carcinogenic illnesses associated with THC contaminants. The hazard index (HI) values for oral exposure shows that (HI > 1) which indicates that the consumption of the water predisposes them to potential health risk. The result for the integrated carcinogenic risk (ICR) values classified the surface water from Orhionmwon River as Grade VI (high risk – 10 -3) which calls for immediate attention and adequate action and should be further investigated for heavy metals such as lead and chromium

Genotoxicity refers to the ability of certain physical or chemical agents to cause damage to thegenetic material DNA and RNA within cells, thereby affecting their structural and functionaintegrity. This study was designed to evaluate the genotoxic effects of vehicular emissions onintra state drivers at central park Benin city. The central objective was to determine whethersustained exposure to vehicular fumes induces measurable genotoxic damage in these individualsA total of 100 buccal cell samples were collected from 25 commercial bus drivers, eachcontributing four samples (two from each cheek). The samples were analyzed using the BuccaMicronucleus Cytome Assay.The results obtained from the exposed group were compared with36 buccal cell samples collected from nine individuals who served as negative controls, each alsocontributing four samples. Altogether, 3,400 cells were examined under a light microscope 2,500from the exposed group and 900 from the control group, to identify and quantify nuclearaberrations such as micronuclei, binucleated, and anucleated cells.The mean frequencies omicronucleated, binucleated and anucleated cells in exposed drivers where significantly highe(p< 0.05) than those in the control. By systematically comparing these findings, this studyprovides critical insights into the potential of vehicular emissions to induce genetic instabilityand cellular damage among occupationally exposed individuals. The outcomes underscore thebiological impact of prolonged exposure to traffic-related air pollutants and highlight the urgenneed for strengthened environmental policies and public health measures aimed at minimizinggenotoxic risks in urban populations