Geoelectrical investigation and hydrochemical analysis of groundwater in a waste dump environment, Isolo, Lagos

Abstract

Geoelectrical and hydrochemical analysis of groundwater in a waste dump environment was carried out to investigate the effect of the infiltrations of leachates and other sources of pollution from waste dump on groundwater. This was done by engaging the vertical electrical sounding method and laboratory water sample analysis. An Abem SAS 3000 terrameter was used to acquire the geophysical data from the vicinity of a major dumpsite called Oke Afa refuse dumpsite at Isolo, Lagos. The WINRESIST (version1.0) software was adopted in the interpretation of the survey data. Groundwater samples from boreholes were collected from the vicinity of the dumpsite with the aim of assessing the physiochemical impacts of the waste dumps on the quality of groundwater. Levels of various physiochemical parameters investigated include total dissolved solids (TDS), alkalinity, pH, electrical conductivity (EC), and hardness using standard analytical methods. Traces of metals like Fe, Cu, Zn, Mg and Na were equally determined using flame atomic absorption spectrophotometer (Unicam model 911). Many of the parameters determined following the specification of the World Health Organisation (WHO), groundwater samples in the area were found to be inadmissible for human consumption. This raises the question of toxicities of these elements, hence it is a threat to man. This shows that the groundwater is polluted because of the high conductivity of the water samples. This was confirmed by the water analysis from the study area in the laboratory.

Key words: Geoelectrical investigation, hydrochemical analysis, major dumpsite, groundwater.