The objective of this project is to obtain a better understanding than is now existant of the transport of groundwater contaminants in the subsurface environment. Laboratory work will be conducted to study the simultaneous movement of multiple fluids in porous media and biodegradation of contaminants in flowing aqueous solutions. The mathematical characterization obtained from this work will then be related to its potential applicability in field-scale applications that could be utilized to address environmental engineering problems relating to and associated with aquifers that are contaminated.