Read the full story from U.S. EPA.
One promising solution for cleaning up contaminated groundwater systems is phytoremediation. Phytoremediation techniques use living plants as a cost-effective, environmentally friendly approach for cleaning up contaminated soil and groundwater. Since the mid-1990s, plant systems have been used at several Superfund and private sites to contain and degrade contaminants. Phytoremediation of groundwater using trees is firmly established as a successful remediation technology for certain contaminants, particularly petroleum and chlorine-based products and solvents. Through a process called, phytodegradation, trees have been shown to degrade dissolvable contaminants in the root system and in the plant. For example, trees can break down contaminants through enzymes within the plant. Pollutants are degraded through oxidization and turned into carbon dioxide.
However, one limitation is that tree roots cannot always reach the depth where the contaminated aquifer is located. To find a solution to this issue, EPA researchers conducted a pilot scale study to test a system for extracting contaminated water from a deep aquifer and used drip irrigation on contained sets of trees to determine if and to what extent the trees can treat the deep aquifer contaminated water.