Investigating the quality of groundwater in Ibeju-Lekki Local Government Area, Lagos State

ABSTRACT This study assessed the groundwater quality in the rapidly urbanizing peri-urban region of the Ibeju-Lekki Local Government Area in Lagos State, Nigeria, during the rainy season. This study employed a two-stage sampling technique to select representative sampling locations, including boreholes and hand-dug wells. Seven towns in Ibeju-Lekki were sampled for this study. A total of 14 sampling points were chosen for the analysis of 15 water parameters, which included five physical parameters (NTU, TCU, E.C. TDS and TSS), eight (8) chemical parameters (pH, T.H. Ca, Mg, Cl-, NO3-, SO42- and Fe), and two (2) microbial parameters (E.Coli count and BOD) after standard procedures. The data obtained were subjected to statistical analysis using Python to assess correlations between the physicochemical parameters. The results were compared with water quality standards set by the World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). In addition, a water quality index (WQI) was calculated to provide a single numerical expression of the overall water quality. The findings revealed variations in the quality of borehole and well water, with some parameters exceeding the recommended standards, such as magnesium and iron concentrations. The presence of elevated turbidity, total dissolved solids (TDS), and electrical conductivity (E.C.) in well water indicated potential contamination sources. The study also demonstrated the significance of understanding physicochemical parameter correlations in groundwater quality assessment. The WQI results emphasized that groundwater is suitable for various purposes, including animals and other domestic and agricultural purposes. However, the paper recommended routine monitoring and thorough treatment to address the high magnesium (Mg) and iron (Fe) levels in both borehole and well water sources.