USE OF NATIVE PLANTS FOR REMEDIATION OF TRICHLOROETHYLENE: II. CONIFEROUS TREES.

Area of Science:

• Environmental Science
• Plant Biology
• Bioremediation

Background:

• Trichloroethylene (TCE) is a common groundwater contaminant.
• Hybrid poplar (Populus spp.) is effective for TCE phytoremediation.
• Native species screening is crucial for effective field applications.

Purpose of the Study:

• Compare native southeastern conifers with hybrid poplar for TCE phytoremediation potential.
• Analyze TCE and metabolite concentrations in plant tissues.
• Evaluate growth parameters relevant to phytoremediation.

Main Methods:

• Greenhouse study comparing longleaf pine, Leyland cypress, loblolly pine, and hybrid poplar.
• Exposure to low (50 mg L⁻¹) and high (150 mg L⁻¹) TCE doses for 2 months.
• Analysis of TCE and metabolites (TCEOH, DCAA, TCAA) in plant tissues; measurement of water uptake, height change, transpiration, and biomass.

Main Results:

• All trees accumulated TCE in root and stem tissues.
• Trichloroethanol (TCEOH) detected only in longleaf pine, indicating TCE metabolism.
• Trichloroacetic acid (TCAA) found in hybrid poplar and loblolly pine leaves.
• Conifers showed lower water uptake and slower growth than hybrid poplar.

Conclusions:

• Native conifers, particularly longleaf pine, demonstrate potential for TCE phytoremediation.
• Evergreen conifers offer year-round transpiration benefits for contaminated sites.
• Further research into native species can enhance phytoremediation strategies for TCE-contaminated groundwater.