Date of Award

Spring 4-28-2015

Degree Type


Degree Name

Master of Science in Integrative Biology (MSIB)



Committee Chair/First Advisor

Dr. Dale Lynn Vogelien

Major Professor

Dr. Sigurdur Greipsson

Second Committee Member

Dr. Marina Koether


Lead (Pb) contamination in soil represents a threat to human health and cleanup efforts often requires expensive or environmentally disruptive techniques. Phytoextraction has gained attention as a possible alternative to traditional remediation methods because of lower cost and minimal soil disruption. Panicum virgatum L. (switchgrass) was chemically enhanced with applications of the soil-fungicide benomyl, chelates (EDTA and citric acid), and phytohormones for phytoextraction of Pb from contaminated urban soils in Atlanta, GA. EDTA is often regarded as the most effective chelate, but has potential problems associated with its use due to long persistence time in soil and possible Pb mobilization into groundwater. Citric acid has been proposed as a possible alternative; however no consensus exists on its ability to generate similar phytoextraction without supplemental EDTA application. Chemical application of citric acid, EDTA, benomyl, and phytohormone BAP were tested separately and in combination to determine the efficacy of phtyoextraction. Application of citric acid without supplemental EDTA application was found to produce shoot Pb concentrations no different than those of plants treated with EDTA, indicating there was no benefit of EDTA application to translocation of Pb into foliage. Application of BAP was found to significantly increase root Pb concentration when combined with EDTA, citric acid, and benomyl (E+B+C+H), but did not result in increased translocation when combined with benomyl and chelates (B+C+H). Total Pb phytoextraction was greatest in plants treated with combined chemical application of B+C and B+C+H. Plants treated with E+B+C and E+B+C+H resulted in less total Pb extracted.