The intrusion of industrial, agricultural and domestically produced organic chemicals and wastes into the aquatic environment is a well known reality and is considered to be one of the most important environmental problems. The widespread finding of these anthroprogenic substances, in addition to naturally occurring organics, and their detrimental impact on the Nation's water resources points to our need to understand how these substances act and react in the environment. Knowledge of transport, persistence, transformation, solubility, sorption, and reaction kinetics is needed to determine the fate of the substances in the hydrosphere. Objectives of project are to (1) identify organic substances associated with the field problem, in aqueous and non- aqueous condition, sorbed and in the unsaturated atmosphere; (2) chemically determine any biotic and/or abiotic degradation or transformations occurring in the field; (3) measure sorption and reaction equilibria and rates within the aqueous system and at the water-mineral interface, using both field observations and laboratory simulations; and (4) determine the behavior of organic solutes and vapors in the unsaturated zone.