This module provides an understanding of the principles of global biogeochemical cycling, and its associated concepts and terminology. This allows understanding of the chemical, physical and biological processes that govern transfer of matter through the environment. These principles are applied to understand environmental issues such as: climate change; stratospheric ozone depletion; food chain transfer of organochlorine pollutants; urban air pollution; acid deposition; and eutrophication etc. The modulealso applies chemical principles to the cycling of water, mass balances and kinetics of weathering and carbonate precipitation in continental environments, with particular reference to stable isotopic studies of water, and the operation of the carbonate system. Fast-reacting environments such as glacial and karstic systems provide a focus in the context of local and global environmental change.