Evaluation of Groundwater Quality in Shallow Aquifers in Minna, North-Central Nigeria using Pollution Load Index

Abstract

Water is essential to life but can serves as a means of diseases transmission when the quality is compromised. The degree of water contamination in an area can be attributed to the local geology and anthropogenic activities. This present study assesses the quality status of groundwater from hand-dug wells in Minna metropolis, North-central Nigeria using geo-statistical techniques. A total of eighteen samples were collected from hand-dug wells and taken to the laboratory for relevant physico-chemical and bacteriological analysis.  Result of the analysis indicates that most of the physico-chemical parameters analyzed compete fovourably with the guideline for safe drinking water recommended by the Nigeria Standard for Drinking Water Quality and World Health Organization except the following parameters Mn, Fe, NO₃, colour and total coliform whose concentration in some location exceed their respective recommended maximum permissible limit for a safe water. The observed high concentration of Mn and Fe may be attributed to bedrock dissolution through weathering processes while the enriched concentration of NO₃ can be due to fertilizer application by farmers in the area. The presence of total coliform in water is an indication of faecal contamination due poor hygiene. The dissolution of these parameters in water generally affects the colour. The pH, indicate that the water is slightly alkaline.  The dominant water type in the area as revealed by Piper diagram, Stiff and Durov diagrams is Mg–HCO^3-. The water quality index value indicates that the quality of the water in the area is poor while the outcome of metal pollution index revealed that the water in the area is slightly to moderately contaminated.  Siting of hand-dug well far away from septic tanks, boiling of the water and good hygiene practice is recommended.

Keywords: Groundwater Quality Assessment, Water Quality and Pollution Index, Hand-dug wells, Minna, North-Central Nigeria