2D electrical resistivity imaging and induced polarization monitoring for groundwater contamination in an uncontrolled landfill. Case study: Gyadi-Gyadi Tarauni LGA, Kano, Nigeria

Abstract

This study investigated the impact of the Gyadi-Gyadi dumpsite on groundwater quality
using Geophysical and Physicochemical methods. The area is located between latitudes
11°58ʹ15ʺN to 12°02ʹ22ʺN and longitudes 08°32ʹ55ʺE to 08°38ʹ50ʺE. Data were collected at
a length of 150 m to four profiles using Advance Geoscience Imaging (AGI) SuperSting R1/
induced polarization (IP) resistivity meter. Results from the resistivity model showed that the
profiles were underlain by four lithologic layers which involved lateritic soil, clay sand, highly
weathered basement complex, and partially weathered basement complex rocks, respec-
tively. The possible water bearing identified zones existed between the horizontal distance
of 40 to 150 m at depth of 15 m in Profile 1; 25 to 45 m depth of 15 m in Profile 2; 35 to
50 m and 75 to 90 m, depth of 13 m in Profile 3; and 40 to 70 m, depth of 16 m in Profile 4,
respectively. The IP result revealed that the waste in the dumpsite was buried to a depth of
over 16 m along the profiles. The physicochemical results when compared with the WHO
standard and Nigerian Standard for Drinking Water show that the pH of the water samples
and Zn (0.121 to 0.975 mg/l) were within the permissible limit. Parameters such as the elec-
trical conductivity (16.5 to 99.3 dS/m), Pb (0.142 to 0.602 mg/l), Cu (1.765 to 0.188 mg/l),
and Cd (0.020 to 0.083 mg/l) were above the permissible limit. The results of this study iden-
tified the presence of conductive zones around the profiles, thus, indicating the surrounding
underground water around the dumpsite may have been contaminated, especially in Profile
2 and Profile 3 having low resistivity values of 12 and 17 Ωm, which were indicative of highly
conductive area as a result of leachate migration