Short-term and long-term permeabilities of contaminated clays

The change in hydraulic conductivity of saturated clays due to short-term and long-term exposure of organic chemicals to clays is investigated to explain the change in hydraulic conductivity of contaminated soils. The long-term exposure of soils to chemicals is simulated in a laboratory environment by premixing chemicals with soils. Under short-term and simulated long-term exposures of water soluble chemicals to soils, the hydraulic conductivities of laboratory consolidated clays are measured and reported. The permeability tests are performed using the both flexi-wall and modified fixed-wall permeameters with soil samples subjected to confining pressures. The fixed-wall and flexi-wall permeameters produced similar results. The short-term permeability tests showed a change in hydraulic conductivity values but not the intrinsic permeabilities of soils. The simulated long-term exposure of organic chemicals to soils showed a change in the soil structure and an increase in the intrinsic permeability of soils. The increasing trend in the intrinsic permeability of a given soil was weakly correlated to the decreasing dielectric constant of the pore fluid.