Geostatistical-based spatial distribution of in-situ groundwater quality parameters in the crystalline basement aquifer in urban and peri-urban city: A case study of Akure, Nigeria

This study examines the spatial distribution of in-situ groundwater quality parameters in the crystalline basement aquifer in Akure City, Nigeria using geostatistical methods. The area was divided into urban and peri-urban areas. Water samples were taken to the laboratory for characterization of the water quality parameters in the water samples obtained in the study area. The oil/water interphase meter was used to determine the depth to the surface of the selected wells in the study area. The depth of the well is between 3.07 and 7.03 meters. The well depth was divided into four categories: Low (3.07 to 7.03 m), Moderate (4.88 to 5.05 m), High (5.06 to 5.22 m), and Very High (5.23 to 7.03 m). Four categories were used to classify the well depth: Low (2.27 to 4.18 m), Moderate (4.19 to 4.29 m), High (4.30 to 4.41 m), and Very High (4.42 to 6.32 m). The pH scale is 5.48 to 6.71. Four pH ranges were identified: Low (5.48 to 5.91), Moderate (5.92 to 6.20), High (6.21 to 6.41), and Very High (6.42 to 6.71). Four categories were assigned to the ORP: Low (29.71% to 45.63%), Moderate (45.64 percent to 57.42%), High (57.43 percent to 66.16%), and Very High (66.17 percent to 77.95%). There were four categories for the Electrical Conductivity distribution (EC): Low (100.64 µS/cm to 242.50 µS/cm), Moderate (242.51 µS/cm to 347.61 µS/cm), High (347.52 µS/cm to 425.49 µS/cm), and Very High (425.50 µS/cm to 483.20 µS/cm). There were four categories for the Total Dissolved Solid (TDS): Low (50.87 ppm to 120.75 ppm), Moderate (120.76 ppm to 172.53 ppm), High (172.54 ppm to 210.89 ppm), and Very High (210.90 ppm to 239.32 ppm).