Assessment of Spatio-Temporal Variation of Groundwater Quality in Udi-Ezeagu Watershed, Enugu Area Southeastern Nigeria

Abstract

This study was carried out to assess the spatio-temporal variation of groundwater quality in Udi-Ezeagu Watershed, Enugu Area, Southeastern Nigeria. The specific objectives were to determine the physical, chemical and microbiological characteristics of groundwater samples in space and time and to ascertain the quality of groundwater using the parameter in comparison with WHO permissible limits. A total of five (5) groundwater samples were collected in triplicates from boreholes located at Ninth Mile Corner, Obioma, Umuase, Abor and Akama-Amankwo at two different time scales. The samples were collected in April (before the onset of rainy season) and September (before the cessation of rainy season), in 2014. The groundwater samples were analyzed in the laboratory for their physical, chemical and microbiological characteristics. On comparing the results with standard values recommended by World Health Organization (WHO), it was discovered that most of the groundwater samples were within permissible limits with slight variation across the locations and in seasons. However, pH of the groundwater samples were not within the permissible limit of 6.50mg/l – 8.50mg/l in four different locations which are Ninth Mile Corner, Umuase, Abor and Akama-Amankwo with pH values of 5.60, 6.20, 5.00 and 5.00. Total hardness of the groundwater samples with values of 12.00mg/l, 58.50mg/l, 45.00mg/l, 15.50mg/l and 11.70mg/l in the dry season and 8.00mg/l, 59.00mg/l, 43.00mg/l, 12.00mg/l and 7.00mg/l respectively in the rainy season were not within the permissible limit of 100.00mg/l – 200.00mg/l in all the locations and in the seasons for Ninth Mile Corner, Obioma, Umuase, Abor and Akama-Amankwo respectively. Magnesium hardness of the groundwater samples with values ranging from 1.50mg/l - 1.65 in the dry season and 5.60mg/l - 6.80mg/l respectively in the rainy season were slightly above the permissible limit of 1.00mg/l in all the locations and in seasons. Total coliform were absent in all the locations during the dry season and was slightly in excess during the rainy season at 9th Mile Corner and Abor with a value of 4.00 per 100ml against the permissible limit 3.00. The study found out that minimal treatment is required in the study area and recommends continuous monitoring of the groundwater supply to keep the quality in check.