ASSESSMENT OF IRON-SMELTING INDUSTRY ON GROUNDWATER (A CASE STUDY OF KAM ROLLING MILL) JIMBA OJA, KWARA STATE.

This study evaluated the potential impact of Effluent generated from KAM Steel Rolling Company, a secondary steel processing facility located in Jimba Oja, Ifelodun Local Government Area, Kwara State, Nigeria, on the quality of shallow groundwater used by the surrounding community. Groundwater samples were collected from four boreholes/hand-dug wells at varying distances from the mill and one control point approximately 500 m away and Raw effluent from Kam Steel rolling Mill. Samples were analyzed for selected physicochemical parameters (pH, turbidity, color, total dissolved solids, total hardness, alkalinity, fluoride, nitrate, nitrite) and heavy metals (Fe, Cu, Pb, Zn, Cd) using standard methods at Obafemi Awolowo University, Department of Civil Engineering Laboratory. Results revealed clear signs of early-stage industrial effluent despite the relatively short operational history of the plant. Turbidity in all impacted samples (28.92–30.96 NTU) was virtually identical to untreated rolling-mill effluent (30.89 NTU) and exceeded WHO/NSDWQ limits by more than a factor of five, confirming direct infiltration of mill scale and oil emulsions. Groundwater pH was consistently acidic (5.92–6.55) compared to the neutral control (6.84), reflecting infiltration and subsequent neutralization of highly alkaline effluent (pH 12.78). Apparent color surpassed the 15 Pt-Co aesthetic limit in every borehole, while one sample exhibited fluoride at 4 mg/Lmatching effluent concentration and 2.7 times the permissible 1.5 mg/Lindicating localized leaching from process additives. Nitrite was uniformly elevated at 1 mg/L (exceeding NSDWQ 0.2 mg/L and WHO 0.3 mg/L), and nitrate reached the 10 mg/L ceiling in half the samples.Dissolved heavy metals (Fe, Pb, Cu, Zn, Cd) remained below detection or well within regulatory thresholds. Total dissolved solids, hardness, and alkalinity posed no concern.The findings demonstrate that, although gross heavy-metal contamination has not yet occurred, aesthetic degradation and specific secondary parameters already render the groundwater unsuitable for direct domestic consumption without treatment. Immediate installation of engineered effluent treatment, regular monitoring, and community water purification are strongly recommended to protect public health and prevent irreversible aquifer impairment. Keywords: Steel Effluent, Groundwater Contamination, Physiochemical Parameters