||Water plays an integral part in every ecosystem and many industrial processes. Nearly all water quality evaluations rely on water chemistry analyses and the determination of the concentrations of various chemical compounds or substances. This course introduces the principles and applications of chemical equilibrium in aquatic systems in a thorough yet easily accessible presentation. The main objective of this course emphasizes on the application of principles from chemical thermodynamics and kinetics to the study and interpretation of the chemical characteristics of complex natural water systems. Explanation of the chemical composition of natural waters from a consideration of metal ion solubility controls, pH, carbonate equilibria, absorption reactions, redox reactions, and oxygenation reactions which occur in natural aquatic environments.