OBSERVATIONS ON THE MIGRATION OF CHLORINATED SOLVENTS IN POROUS MEDIA

摘要

Preliminary laboratory tests have been carried out to investigate the migration of chlorinated compounds in coarse-grained soils above and below the water table. The laboratory tests were carried out by staining trichloroethylene (TCE) with the rec dye Sudan IV (Fisher Scientific) and monitoring the migration through a sample of glass ballotini. The results illustrate the downward migration TCE as a finger and eventually pooling at the base of the container. In the dry sample, TCE preferentially coated the ballotini as the wetting fluid. In a moist sample of ballotini, water displaced TCE as the wetting fluid and created discrete globules of TCE (termed residuals) within a broader band of pollution. Penetration of TCE below the water table (once sufficient head overcame capillary pressures between soil grains) was characterised by preferential wetted pathways.