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PT12 Metals and Bioaccumulation
(PT164) The impact of EDTA on the bioaccumulation of cadmium by hydroponic dwarf sunflowers.
Meighan, M1, MacNeil, J1, 1 Chatham College, Pittsburgh, PA, USA
ABSTRACT- Phytoremediation has been proposed as an effective, cost-efficient tool for restoring metal-contaminated soil, sediment and ground water. Past studies have shown that the application of chelating agents can improve metal uptake in plants, although the relative effectiveness of such application varies as a function of the chelator, the characteristics of the soil, the metal ion and the plant species under study. In the present work, hydroponically grown dwarf sunflowers (Helianthus annuus) were immersed in solutions containing between 3 ppm and 30 ppm cadmium cations. Some experimental solutions included nitrate and phosphate ions, while others contained solely DI water. In the absence of chelators, cadmium was bound tightly at the roots, transpiration was significantly impaired and plant health deteriorated. No cadmium uptake into shoot was evidenced. The presence of EDTA in 3x molar excess inhibited the accumulation of cadmium on the root structures of the plant, allowing the plants to look healthier and live longer than their experimental counterparts. When EDTA was applied concurrently with nitrate and phosphate anions, cadmium was translocated into the leaves. This uptake was not observed when nitrate and phosphate anions were not present in solution. Current experiments are investigating the synergistic relationship between phosphate and nitrate anions with the EDTA.
Key words: cadmium, phytoremediation, sunflower, chelator
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