USING TREES AS A BARRIER TO METALS-CONTAMINATED, SALINE GROUNDWATER

Groundwater in the shallow transmissive zone at an AMOCO site is highly saline and contaminated with inorganics and radionuclides that exceed the U.S. Environmental Protection Agency maximum concentration limits. Under a voluntary cleanup program agreement, additional response actions would be required (i.e., additional containment, pump and treat, etc.) if the plume migrates past the compliance monitoring boundary.

A dilution study and greenhouse feasibility study are under way to determine the suitability of installing a tree barrier strip at the site. The installation of dense rows of deep-rooted water-loving trees perpendicular to groundwater flow and along the leading edge of the plume may serve as added insurance against further off-site migration; the trees essentially acting as a flow confinement system.