Assessment of Well Water Quality in Obudu Cross River Nigeria: A Multi- Parameter and Regression-Based Water Quality Index Analysis

Access to clean and safe drinking water is essential for human health and well-being. This study evaluates the water quality of well water in Obudu Local Government Area, Cross River State, Nigeria, by correlating the Water Quality Index (WQI) with various physical, chemical, and bacteriological parameters. 65 well water samples were analysed using the Oregon WQI model,incorporating parameters such as temperature, electrical conductivity, pH, turbidity, total dissolved solids (TDS), heavy metals, and microbial contaminants. Results showed that temperature ranged from 26.1–27.9°C, pH from 7.01–7.98, and electrical conductivity from 138.1–217.2 µS/cm, all within acceptable World Health Organization (WHO) limits. However, concentrations of lead (0.01–0.08 mg/L), Iron (1.90-5.32) and total hardness (120.5-202.3) exceeded the WHO standard of 0.01 mg/L, 0.3 mg/l and less than 150 respectively. Results of total Coliforms and faecal Coliforms were too numerous to count (TNTC) in several wells, indicating contamination. WQI values ranged from 67.5 to 99.54, with some wells classified as poor to fair water quality (60–84 WQI), requiring treatment before consumption. Using multiple linear regression analysis (MLRA) water quality via WQI could be predicted by some physical, chemical and bacteriological parameters from Models 1-4. Model1 with adjusted R² value of 0.873 provided the best correlation. Water treatment interventions and sustainable management strategies are required to ensure safe drinking water for the local population.