Abstract

Vertical electrical sounding, 2-D resistivity imaging and hydrochemical analysis have been applied in the study of the aquifer around the automobile mechanic workshop in Sapele, Nigeria. Fifteen sounding points were done and six resistivity imaging employing dipole-dipole configuration around the automobile mechanic village. The geoelectric sections revealed four distinct layers namely topsoil, lateritic sand, fine sand, and medium coarse sand. The third and the fourth layers were identified as the aquiferous layers with resistivity values and depth ranged from 17.4 Ωm to 459 Ωm and 4.5 m to 10.0 m respectively. The low resistivity values of 19.1 Ωm to 454 Ωm obtained around the automobile mechanic workshop in the geoelectric sections is attributed to the effect of leachate from the activities of the workshop. The aquifer protective capacity was found to be predominantly weak. The results of the hydrochemical analysis of water samples from boreholes revealed that the concentration of cadmium, nickel and lead are greater than the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO), implying that the groundwater is polluted by leachates. The results of the pollution load index (PLI) which is greater than one, revealed that the groundwater from the sampling sites is deteriorating and polluted due to the presence of heavy metals, and the water quality indices (WQI) is >300 which reveals that the water is unsafe for drinking. Based on these, the water in the study area was rated as unsuitable and thus need proper treatment before domestic use.