Phytoextraction of Lead in Soil Using Lead-Accumulating Grass (Vetiveria Zizanioides) in the Presence of Beneficial Arbuscular Mycorrhizal Fungi
Pravin A. Punamiya, Mandakini J. Patel, Rupali Datta, and Dibyendu Sarkar
Environmental Geochemistry Laboratory, University of Texas At San Antonio, One UTSA circle, San Antonio, TX
Lead (Pb) is a toxic metal that can be harmful to humans when ingested or inhaled, particularly to children under the age of six. Lead poisoning can cause a number of adverse human health effects, but is particularly detrimental to the development of children. Soil ingestion by hand-to-mouth activity is a major source to lead exposure to children. Primary source of Pb pollution includes industrial activities, vehicular emission, coal burning, refuse incineration, pesticide applications, and paints applied to structural surfaces. Lead in paints is the principal source of human exposure to environmental Pb in the U.S. Despite efforts made to reduce residential exposure to Pb (including setting a maximum allowable Pb content in paint of 0.06% in 1977), there exists a significant number of housing facilities in every city in the U.S. that were built prior to the implementation of that policy. Current technologies to remediate lead contaminated soils are very expensive, and it is vital to find an environmentally friendly way to remediate these lead contaminated soils. Our previous research has shown that Vetiver grass (Vetiveria zizanioides), a fast-growing, high biomass plant, is an effective accumulator of lead. However, uptake of lead by plants is limited by the strong association of Pb with organic matter, Fe-Mn oxides, clays, and precipitation as carbonates, hydroxides, and phosphates in the soil. The beneficial arbuscular mycorrhizal fungi have shown the potential of solubilizing the lead mineral; which could potentially increase the plant-availability of lead. A greenhouse study was executed to elucidate the ability of beneficial arbuscular mycorrhizal fungi to solubilize lead, and enhance the uptake of lead by vetiver grass.
AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas