| Mature trees, suspected of intercepting trichloroethylene (TCE) contaminated groundwater at Operable Unit 2 (OU2), Hill Air Force Base, UT, and Site 15, Vandenberg Air Force Base, CA were sampled for evidence of TCE uptake, phytovolatilization, and metabolism. TCE was found in all 6 trees at OU2 but in only 2 of 19 trees at Site 15. The mean concentration of TCE in the OU2 phytovolatilization samples was 16 p mu/L, while no phytovolatilization was observed at Site 15. Phytovolatilization is estimated to remove 410 to 730 mg of TCE per tree per year from the OU2 aquifer. No TCE metabolites were found at OU2, but were found in 2 of 19 Site 15 trees where leaves may not be dropped annually. The difference between sites is likely due to lower TCE groundwater concentrations at Site 15 and the higher transpiration rates and greater groundwater utilization by trees at OU2. |
