Wednesday, November 7, 2007 - 1:00 PM
326-11

Energy Crops for Reducing Areawide Lead Soil Contamination.

Mark Elless1, Dongmei Wang2, and Michael J. Blaylock2. (1) Edenspace Systems Corp., Edenspace Systems Corporation, 3810 Concorde Parkway Suite 100, Chantilly, VA 20151-1131, (2) Edenspace Systems Corporation, 3810 Concorde Parkway, Suite 100, Dulles, VA 20151-1131

Because areawide lead soil contamination poses significant risks to large populations in the United States, reducing lead levels in these soils is an important environmental health priority. Current methods that address localized, small-scale lead contamination, such as excavation and replacement of soil, are too expensive for large-scale application. This study seeks to develop an innovative, low-cost method of extracting lead from soils over wide areas using TPA-based phytoextraction and high-biomass grasses suitable for energy production. TPAs are defined as transient phytoextraction agents, chelants that are known to biodegrade more rapidly than EDTA, thereby minimizing the risk of off-site migration of chelated lead. Previous investigations have shown the ability of TPA-based phytoextraction using turf grasses to safely remediate soil lead at urban residences. This project will evaluate switchgrass and elephant grass, two high-biomass plants targeted for production of power and cellulosic ethanol, for their ability to accumulate lead following TPA treatment from soils contaminated by lead smelters and mining compared to a spiked soil. Mobility of the lead remaining in each soil after treatment will be assessed by sequential extraction to determine changes, if any, in post-treatment soil lead bioavailability due to TPA application. The biomass harvested following lead phytoextraction will be processed to determine if the lead interferes with ethanol production. In addition, attempts to recycle the lead from the biomass will also be investigated. The expected end result of this study will be to establish the foundation for a low-cost, solar powered method of removing lead over large areas of soil that also produces useful renewable energy co-products, thereby offsetting a portion of the remedial costs.