This course will cover selected aspects of the chemistry of aquatic systems. Lectures cover basic principles of physical-organic chemistry relevant to the aquatic environment under realistic conditions. Specific topics covered in Part I include the basic principles of equilibrium chemical and physical processes important natural waters. Topics include: chemical potential, fugacity, phase transfer, acid-base chemistry, metal-ligand substitution chemistry, surface chemistry, octanol-water partitioning, air-water partitioning, partitioning to solid organic matter and biomedia, sorption processes, air-water exchange dynamics, and the kinetics and mechanisms of coupled organic and inorganic redox reactions. Thermodynamics, transport, phase transfer and kinetics are emphasized.