Polychlorinated biphenyl diffusion through HDPE geomembrane

Experiments conducted to evaluate the partitioning coefficient from aqueous solution into and out of high-density polyethylene geomembrane, as well as the diffusion coefficient through the geomembrane are reported. The best estimate partitioning coefficient (S_gf) is about 150 000 with an upper-bound estimate of 325 000. The best estimate diffusion coefficient (D_g) is 1.0 × 10⁻¹⁴ m²/s, with lower and upper bounds of 0.5 × 10⁻¹⁴ and 5 × 10⁻¹⁴, respectively. Using the diffusive properties obtained from the above experiments, the potential impacts on an aquifer of the migration of polychlorinated biphenyls and chloride are compared for a composite liner in a hypothetical municipal solid waste landfill. It is shown that, with good construction quality assurance to limit the number of holes and length of covered wrinkles to acceptably low values, a modern composite liner limited the impact of polychlorinated biphenyls on the aquifer concentration to well below regulatory limits.