ers and the second mustard plants. Following treatment, analysis indicated soil lead concentrations were below the target clean-up criteria. The project resulted in an estimated saving of $1,100,000 over hazardous waste disposal. 5) 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 trees and letting them grow. Additional studies showed that the trees did not release TCE into the air, as no measurable TCE was present in the air immediately surrounding the leaves (captured in small leaf bags and analyzed) or in the general atmosphere (using a laser technology that can see TCE in the air in the tree canopy). CONCLUSION: Phytoremediation is an aesthetically pleasing, solar-energy driven, and passive technique that can be used at sites with low to moderate levels of contamination. Phytoremediation is more than just planting and letting the foliage grow; the site must be engineered to prevent erosion and flooding and maximize pollutant uptake. Currently, the majority of research is concentrated on determining the best plant for the job, quantifying the mechanisms by which the plants convert pollutants, and determining which contaminants are amenable to phytoremediation. Polluted sites are being studied, and phytoremediation looks promising for a variety of contaminants....
