This book provides adequate information on a research that integrated both geophysical and hydrochemical methods to investigate subsoil and groundwater pollution around three cassava processing factories at Ireti-Ayo Community, Ilesha, Southwestern Nigeria. The geophysical investigation reveals that the topsoil at and around the cassava effluent dumping units had relatively low resistivity diagonistic of the cassava effluent pollution plume impacted zones. The hydrochemical analysis reveals that the concentration of all the physicochemical parameters of well water samples in the area do not exceed the WHO maximum permissible standards for drinking water. Other details are presented in this book.