Geophysical and hydrochemical assessment of groundwater pollution due to a dumpsite in Lagos state, Nigeria

The impact of the buried refuse at the abandoned Achakpo refuse dumpsite in Ajeromi-Ifelodun Local Government area of Lagos State on the groundwater has been carried out using geophysical and hydrochemical methods. The geophysical method involved vertical electrical soundings while the hydrochemical analysis carried out on the samples of groundwater from four hand dug wells in the vicinity of refuse dumpsite and one sample of surface water. Three geoelectric layers were delineated from the interpretation of vertical electrical sounding data and the map of the depth to the top of resistive bed was produced to show the extent of pollution. Supporting evidence was provided by the hydrochemical analysis of samples from groundwater and surface water which show very high value of conductivity, total dissolved solids, total suspended solids, Alkalinity, Total hardness, Ca2+, Fe2+ and PO43+.