Keywords: human health, Lagos, Nigeria, multivariate analysis, septic tanks, shallow wells, water quality, electrical conductivity, pH, total dissolved solids, temperature, salinity, chloride, calcium, alkalinity, total hardness, sulphate, nitrate, magnesium, sewage, wastewater treatment
Evaluating the effects of septic tank on shallow wells in Iba housing estate, Ojo LGA, Lagos
Water samples from 30 shallow wells were measured for depth, depth to water table, and distance to septic tank. In situ parameters including electrical conductivity, pH, total dissolved solids, and temperature were measured using portable meters. Chemical parameters including salinity, chloride, calcium, alkalinity and total hardness were determined using titrimetry method. Sulphate and nitrate were determined by spectrophotometer while magnesium was determined by atomic absorption spectrophotometer. Results of the functional linear relationship of the parameters show that electrical conductivity and salinity have a significant linear relationship with TDS obtained at 0.999 and 1.000 respectively. Factor analysis extracted four factors and explains 89.2% of total variance. Factors I and II represent wastewater/sewage and nitrate sources. The study concluded that microbiological test and appropriate treatment will be required to make it fit for consumption. It was recommended that the locations of septic tanks around wells should follow international standards to prevent contamination.