to the earth after aquaculture must be permitted. 8.Less efficient for hydrophobic contaminants, which bind tightly to soil (Black, 1997).At the Naval Air Station Joint Reserve Base Fort Worth, phytoremediation is being usedto clean up trichloroethylene (TCE) from a shallow, thin aerobic aquifer. Cottonwoods are beingused, and after 1 year, the trees are beginning to show signs of taking the TCE out of the aquifer.(Hecht, 1998) At the Iowa Army Ammunitions Plant, phytoremediation is being used as a polishingtreatment for explosive-contaminated soil and groundwater. The demonstration, which ended inMarch, 1997, used native aquatic plant and hybrid poplars to remediate the site where anestimated 1-5% of the original pollutants still remain. A full-scale project is estimated to reducethe contamination by an order of magnitude (Hecht, 1998). After investigating using phytoremediation on a site contaminated with hydrocarbons, theAlabama Department of Environmental Management granted a site. The site involved about1500 cubic yards of soil, and began with approximately 70% of the baseline samples containingover 100 PPM of total petroleum hydrocarbon (TPH). After 1 year of vegetative cover,approximately 83% of the samples contained less than 10-PPM TPH (Hecht, 1998). Phytoremediation was used at the decommissioned Detroit Forge plant to clean upapproximately 5,800 cubic yards of lead-impacted soil. Two plantings were completed, the firstusing sunflowers and the second mustard plants. Following treatment, analysis indicated soillead concentrations were below the target clean-up criteria. The project resulted in an estimatedsaving of $1,100,000 over hazardous waste disposal (Hecht, 1998). Water, soil, and trees transpired gases were monitored to track the fate of TCE. About 2-4% of the TCE remained in the effluent as compared to 68% in a non-vegetated control group.The field trial demonstrated that over 95% of TCE were removed by planting t...
