ABSTRACT
The transport and fate of organic chemicals in the subsurface is a topic of great interest. Mathematical models are used to simulate the transport and fate of dissolved chemicals through soils and aquifers for a variety of purposes. Environmental regulators use models to evaluate the threat posed to groundwater by chemicals entering the subsurface. Industrial chemists use models to assess the fate of pre-production chemicals. The distribution of organic chemicals between solution and solid phases has been and is being studied within several disciplines, including soil science, geology, environmental science and engineering, analytical chemistry, and chemical engineering. The disposition of biomass in the subsurface may be described using one of three approaches: biofilms; microcolonies; and macroscopically uniform distribution. The spatial distribution of bacteria in porous media has been examined by few investigators. The growth status of the biomass is a major factor controlling the form of transformation model that is appropriate.
