PHYTOREMEDIATION OF TRICHLOROETHYLENE ANDPERCHLOROETHYLENE AT THE SAVANNAH RIVER SITE

摘要

Bioremediation of chlorinated solvents, both natural and accelerated, is exemplified byphytoremediation and biodegradation by rhizosphere microorganisms. Phytoremediation is theuse of vegetation for the treatment of contaminated soils, sediments, and water. The potential forphytoremediation of chlorinated solvents has been demonstrated at the Savannah River Site(SRS) Miscellaneous Chemical Basin, Southern Sector of A/M Area and TNX/D-Area. Recentcharacterization work at the SRS has delineated widespread plumes (1-2 miles) of lowconcentration (40 ppb –10-ppm range) trichloroethylene (TCE) and perchloroethylene (PCE)contaminated groundwater. Phytoremediation deployments are underway for TCE and PCEphytoremediation in select SRS areas. Phytoremediation appears to be an excellent technologyto intercept and control plume migration.The ongoing Southern Sector treatability study is part of a multi- year field study of SRSseepline-soil systems maintained under saturated conditions. The primary focus is on determining howtrees, seepline groundcover, soil microbial communities, and geochemical and surface-volatilizationprocesses affect TCE and PCE in contaminated groundwater that flows through surface seepline areas.Therefore, FY00 represented an initial acclimation phase for soil and plant systems and will facilitateexamination of seepline phyto- and bioactivity in subsequent growth season in FY01.The Southern Sector project has concentrated on groundwater upgradient of the seepline at TimsBranch. The field research has the objective of determining the efficiency of plants and soil for in situbioremediation of the VOCs, TCE and PCE, under seepline conditions. Well MSB 88C was selected asthe groundwater supply because of it’s VOC concentrations (TCE 188 ppb, PCE 55 ppb) and proximityto the seepline. Three phytoreactors were deployed with soil from the seepline. Phytoreactors 1 and 2were planted with loblolly pines (Pinus taeda) and hybrid poplars (Trichocarpa X deltoides)