Chlorinated Ethenes from Ground Water in Tree Trunks

By Don A. Vroblesky, Christopher T. Nietch, and James T. Morris

ABSTRACT

The purpose of this investigation was to determine whether tree-core analysis could be used to delineate shallow ground-water contamination by chlorinated ethenes. Analysis of tree cores from baldcypress [Taxodium distichum (L) Rich.], tupelo (Nyssa aquatica L.), sweetgum (Liquidambar stryaciflua L.), oak (Quercus spp.), sycamore (Platanus occidentalis L.), and loblolly pine (Pinus taeda L.) growing over shallow ground water contaminated with cis-1,2-dichloroethene (cDCE) and trichloroethene (TCE) showed that those compounds also were present in the trees. The cores were collected and analyzed by headspace gas chromatography. Baldcypress, tupelo, and loblolly pine contained the highest concentrations of TCE, with lesser amounts in nearby oak and sweetgum. The concentrations of cDCE and TCE in various trees appear to reflect the configuration of the chlorinated-solvent ground-water contamination plume. Baldcypress cores collected along 18.6-meter vertical transects of the same trunks showed that TCE concentrations decline by 30 to 70 percent with trunk height. The ability of the tested trees to take up cDCE and TCE make tree coring a potentially cost effective and simple approach to optimizing well placement at this site