A series of centrifuge tests were performed to investigate the behavior of copper ionic migration in unsaturated cohesive soils. From this study

it is indicated that the hydraulic driven flow controlled the migration of copper ions in soils during the period of the first year. The contaminant region changes from a triangular shape in the first year to a more square like later. Vertical movement is more significant than horizontal. Compaction is a very practical method to reduce the hydraulic conductivity of the soil and thus to retard the movement of contaminants. It was demonstrated effective by centrifuge tests. Minor difference of clay content in natural soils will result in significant difference on copper ionic migration. When mixed with bentonite

this barrier effect of clay was enhanced.