This is an award to support research on contaminant interactions with clays used in containment of structures for storing hazardous wastes. The objectives of this research include quantification of the structural changes in clays when they are permeated by organic fluids, determination of the distribution pattern of contaminants in these clays, and examination of the feasibility of removing volatile organic compounds from these clays by a vapor extraction process. This proposal was submitted in response to Program Announcement NSF 88-99, Research Initiation Awards. Results are expected to improve the engineering design of containment ponds, landfills, waste covers and slurry walls associated with storage of hazardous solids and liquids. Results may also be applied in a process for decontamination of contaminated soils by vapor extraction alone or in combination with another physical process, and/or chemical and biologically-based remediation systems.