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PM01 Phytoremediation and Risk Assessment
(PM005) Experimental determination of Pb phytoremediation by Gaillardia pulchella.
Moore, S1, Bradford, A1, Howard, C1, 1 University of Houston- Clear Lake, Houston, Tx, USA
ABSTRACT- Pb (lead) contamination of urban soils is a long-standing, persistent environmental problem. There is increasing interest in developing non-destructive techniques for remediating Pb in these soils. Indian paintbrush, Gaillardia pulchella, is a member of the plant family Asteraceae. Other members of this family are known to hyper-accumulate Pb. G. pulchella is an indigenous plant of the central U.S. and tolerates a wide range of soil types, pH and moisture levels. The purpose of this study was to determine the phytoremediation capabilities of G. pulchella in acidic and non-acidic conditions of lead contaminated soils. Plants were grown from seed in a laboratory setting, in soil composed of 48:38:18 sand:silt:clay. The plants were divided into 3 replicates of 40 pots containing 1kg of soil and 8 plants each. Replicate 1 served as control; replicates 2 and 3 were treated with 500 mg PbNO3; replicate 3 was also treated with HNO3 at a pH of 5.6 to 6.0. Groups of ten from each replicate were harvested beginning 150 days from planting. Three additional groups were harvested at 14, 28 and 42 days. Plants were separated into roots and shoots and frozen at −70C. Samples were processed for Pb analysis using hot acid digestion (modified EPA method 200.3), then analyzed using ICP-AES. Plants in replicate 3 (Pb + HNO3), harvested at 42 days, accumulated the maximum amount of Pb. A greater proportion of Pb was found in the roots compared to above ground biomass in all treatment groups. Like other members of the Asteraceae family, G. pulchella has demonstrated the ability to accumulate Pb from soil, therefore is a good candidate for urban phytoremediation.
Key words: phytoremediation, Indian paintbrush, Lead
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