Investigating Groundwater Quality and Soil Cultivation Viability Using Geophysical and Geochemical Approach at A Dumpsite in Mokwa, Niger State, Nigeria

Abstract

Geophysical survey involving electrical resistivity method, soil and hydro-chemical analyses was conducted around Masallachi Idi dumpsite in (latitudes 9o18' N and longitudes 5o04' E) Mokwa, Niger State, Nigeria with the aim of investigating the degree and impact of the waste dumpsite on the quality of the groundwater and the recent farming activities observed in the study location. Forty Vertical Electrical Sounding survey were carried out at the study location. The Schlumberger array with a maximum electrode spread of 150 m was employed in all the points. Results from the sounding data indicated that the location is generally underlain by three to four geo-electric sections which include top soil, Clay Sandstone, Weathered basement, and Fresh basement. Based on the results obtained, the fractured and the weathered basement constitute the aquifer zones within the study location. These zones are characterized by dominant low resistivity zones <75 Ωm due to the delineated leachate invasions up to the depth of 20 m which indicate very poor soil and groundwater quality. The results of the groundwater samples analyzed in this location revealed contamination by leachates containing Lead, Chromium and Cadmium whose average concentration levels (0.48, 1.06, and 0.04) mg/l respectively exceed the WHO and SON regulated limits. The results of soil analysis indicated that the soil samples collected in this dumpsite were also contaminated by the same elevated highest concentrations of Chromium 136 mg/kg and Cadmium 10.49 mg/kg implying that the poor quality state of both the soil and the groundwater had made it unviable for any agricultural activity or normal consumption. Immediate and appropriate law enactment on stoppage of farming activity within any dumpsite by the government is among the major recommendations.