Comparative fate of [¹⁴C]trichloroethylene in the root zone of plants from a former solvent disposal site

A comparison of the environmental fate of [¹⁴C]trichloroethylene ([¹⁴C]TCE) in vegetated and nonvegetated soils from a contaminated field site indicated increased mineralization (¹⁴CO₂ production) in soils containing vegetation. Mineralization in soils containing Lespedeza cuneata (Dumont), Pinus taeda (L.), Solidago sp. (all collected from a former chlorinated solvent disposal site), and Glycine max, germinated from commercially available seeds, accounted for >26% of the total recovered radioactivity compared with approximately 15% for nonvegetated soil and <9% for control (sterile) soil. Uptake of ¹⁴C into plant tissues ranged from 1 to 21% total for leaves (or needles), stems, and roots and appeared to be related to plant species and water use during the experiment. The higher mineralization rates for [¹⁴C]TCE in the vegetated soils compared with nonvegetated soils indicates that the rhizosphere provides a favorable environment for microbial degradation of organic compounds. Therefore, vegetation may play an important role in enhancing biological remediation of contaminated surface soils in situ.