Mass recovery methods for trichloroethylene in plant tissue

Monitoring expenses form a significant fraction of the costs associated with remediation of contaminated soil and groundwater sites. A novel monitoring method that could result in significant cost savings is the use of plants as monitoring devices; previous work indicates that plant tissue samples, especially trunk (core) and branch samples, can be used to delineate soil and groundwater plumes at phytoremediation sites. An important factor in reducing the uncertainty associated with this sampling method is development of a technique to analyze, both consistently and accurately, the chemicals stored in plant tissue samples. The present research presents a simple, robust, and inexpensive technique to recover most of the contaminant in plant branch tissue, irrespective of the age or species of the plant. Tricholoroethylene (TCE) was the chemical analyzed. A number of headspace and solvent extraction techniques in the literature were evaluated, including headspace extraction at different incubation times and temperatures and solvent extraction using hexane or hot methanol. Extraction using hot methanol was relatively fast, simple, and reliable; this method recovered more than 89% of the TCE present in branches of five different tree species.