"There is an increasing interest in environmental issues. Hydrogeochemistry is very important from viewpoint of environmental impact assessment. Both surface water and ground water are used as sources of water for many purposes. This sub-discipline has been developed due to the importance of water quality issues, and gradually changed into a well established field of research. The study of quantity of water alone is not sufficient to solve the water management problems because its uses for various purposes depend on its quality. In addition, a number of other researchers show that the hydrogeochemical characteristics of ground water and groundwater quality in different aquifers over space and time are important parameters in solving the groundwater management issues. This volume Hydrogeochemistry deals with quality, contamination, chemistry, chemical processes and reactions that take place in various groundwater systems. The purpose of the text is to present comprehensive and practical information necessary for treatment and interpretation of environmental hydrogeochemical data. It provides some baseline data on the geochemical characteristics of the sediments and the water quality. Natural origin of groundwater and groundwater pollution by anthropogenic activities is considered in the groundwater quality analysis for drinking water purpose. Hydrogeochemical processes such as dissolution, precipitation, absorption and desorption, ion exchange reactions and the residence time along the flow path which controls the chemical composition of groundwater, constitutes the other issues that are dealt with in this book. Advances in our ability to quantify these processes will improve our ability to manage our water resources, help us identify potential sources of contamination, and illuminate potential solutions to water-quality problems. To better address societal needs, future advances will require a holistic approach to interpreting geochemical data."