Screening plant species for growth on weathered, petroleum hydrocarbon-contaminated sediments

Rapid and cost-effective techniques are needed to select plant species and genotypes for use in phytoremediation, vegetative capping, or revegetation at hazardous waste sites. A greenhouse screening procedure to aid the selection of plant materials would help increase success and decrease the cost. Twenty-nine vascular plant species were compared for growth in weathered sediments contaminated with petroleum hydrocarbons. An uncontaminated reference soil was used to estimate relative seedling growth in stressed and unstressed conditions. Plants were grown in a greenhouse and harvested at 60 and 180 days after planting to estimate variation in seedling growth and full-season growth. Plant growth characteristics measured included height, aboveground biomass, root biomass, root diameter, root-length density, and root surface area density. Concentration of total petroleum hydrocarbons (TPH) was estimated at the final harvest. Considerable variation existed among species for all characteristics except TPH concentration. Under the conditions and length of this trial, no variations in rates of TPH degradation were detected. In general, plant growth was stunted in the contaminated soil compared with the uncontaminated soil; however, differences among plant species for relative seedling growth indicated that they varied in their tolerance to the petroleum hydrocarbon-contaminated soil. For example, tall fescue, Festuca arundinacea, seemed tolerant to the contaminated soil, whereas barley, Hordeum vulgare, seemed sensitive. Comparison of results from the 60- and 180-day harvests suggested that a short-season greenhouse screening could aid selection of species for planting in contaminated soil, if plant growth results are interpreted along with information on the life history characteristics of the species under consideration.