Physicochemical Profiling and WQI of Ikorodu Boreholes: Nitrate-Iron Risks in Lagos Peri-Urban Aquifers

Abstract

In Ikorodu, a fast-growing suburb of Lagos, Nigeria (6.63°N, 3.48°E, pop. >2.1 million), many families depend on backyard boreholes for drinking water—yet pollution from nearby factories, markets, and farms is putting that supply at risk. Our study looked closely at eight groundwater samples (A–H) from across a 5 km area in February 2026, testing 15 key qualities under steady lab conditions (27.43°C, 46.48% humidity), following standard methods: pH ranged from acidic 4.91 to 6.82, turbidity stayed low at 0.99–1.38 NTU, conductivity 0.8–1.4 mS/cm, TDS 632–924 mg/L, hardness 48–122 mg/L (with magnesium often dominant), iron 0.34–0.96 mg/L, nitrates up to 78.12 mg/L, and more. Stats showed clear differences between samples (ANOVA, p<0.01), a tight link between TDS and conductivity (r=0.98), and an average Water Quality Index of 68.4—mostly "poor to fair," with six samples over WHO safe limits for drinking, especially TDS, nitrates, and iron. For health, this matters: high nitrates in samples D–F could cause "blue baby syndrome" in infants, iron levels might upset stomachs or help bacteria grow, hard water and salts in B and C raise kidney stone or blood pressure worries, and low pH in E could leach more toxins. The brownish tint in most samples hints at iron particles that might spread diseases like cholera, common here. Likely from a mix of natural rocks and human waste, these waters need simple fixes like filters or treatment plants. Stronger checks by local agencies would protect families and support clean water goals.