Effects of Pit Latrines and Poor Design of Sanitary Facilities on Groundwater Quality: A Case Study of Minna and Bida, Northcentral Nigeria

Abstract

A study on the water quality of groundwater in unconfined shallow aquifers was conducted with the aim of assessing physicochemical and bacteriological contamination of groundwater as a result of poor design of water and sanitation facilities in Minna and Bida, Nigeria. The study was conducted using a grid-based approach on wells and boreholes in households. The water has a high Total Dissolved Solids and Electrical Conductivity indicating high concentration of dissolved and suspended materials. The pH is slightly acidic to basic and mean distance of wells to pit latrines, septic tanks and other waste disposal facilities is 12m. Chemical parameters that occur in high concentrations are sulphates, chlorides, nitrates and sodium. Nitrate and chloride are pollution indicators from sewage in groundwater. Total Coliform count, Faecal Coliforms and Faecal Streptococci are very high and far above the maximum permissible limit. Contamination of deeper sources of water from the dug wells is both lateral and vertical with contamination plume spreading to better planned areas. Sanitation facilities in unplanned areas should be upgraded from pit to Ventilated Improved Pit latrines and with adequate provision of water to pour-flush and septic tank system. Septic tanks and soakaways should be designed to protect groundwater from contamination.