This book comprehensively discusses the methods and practices for evaluating geochemical processes in aquifer groundwater. Possible occurrence and mechanisms of rock-water interaction, trace metal mobilization, thermodynamic explanation, actions of aquifer CO2, pollution sources, geogenic influencing factors, and isotope dilution methods are the primary areas of focus. These water quality variables are analyzed using a variety of logical/theoretical explanations, statistical techniques, and experimental procedures to determine the suitability of groundwater for drinking, irrigation, and other industrial purposes. The work is an important addition to hydrogeochemical literature since many existing indexing methods for the assessment of water quality are very old and have some degree of limitation. The book will be a useful resource for students, lecturers, and researchers working in the fields of hydrogeochemistry, hydrology, water pollution, and groundwater quality.