Volume 17, Issue 2 (March 1989)
Preventing and Coping with Water Pollution
Halogenated organic solvents (HOS) have only recently been recognized as a major class of ground water contaminants. The mechanisms for HOS subsurface migration are discussed and the available investigative and remedial techniques summarized. HOS migration involves transport in the saturated and unsaturated zones by any of the following mechanisms: liquid HOS movement, volatilization into and diffusion through the air phase of the unsaturated zone, and aqueous phase transport. Several processes affect the migration. These include advection, dispersion, sorption/desorption, biochemical transformation, volatilization, and diffusion. With an appropriate understanding of how HOS migration occurs, an investigator can more effectively utilize available diagnostic tools such as remote sensing, geophysics, and direct measurements to ascertain the nature, extent, and impacts of a release to the environment. Cost-effective remedial solutions can then be designed and implemented. These solutions can consist of a combination of source control, recovery of “free product”, soil remediation, and ground water restoration.