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Dr. Rupali Datta

Associate Professor, Biological Sciences A Chemically-Catalyzed Phytoextraction Method for Remediation of

Lead Paint Contaminated Soil

Lead poisoning remains the most common environmental health problem affecting children in the United States. Phytoremediation is a cost-effective and “green” technology for cleaning up lead contaminated residential soils in homes built prior to 1978, when lead-based paint was commonly used. Developing a phytoremediation model requires a good understanding of the role of soil properties governing lead availability for plant uptake, as well as the biochemical mechanisms involved in lead uptake and tolerance in the candidate plant. Our long-term goal is to develop and test a phytoremediation model applicable to residential soils with varying physico-chemical properties using a high biomass, metal tolerant grass, Chrysopogon zizanioides (vetiver grass). In order to achieve this goal, we pursued the following objectives (1) Develop prediction models for exchangeable soil lead using lead paint-contaminated residential soils from two cities, San Antonio and Baltimore, (2) Evaluate the effectiveness of vetiver in lead uptake using a biodegradable chelating agent, ethylenediaminedisuccinic acid (EDDS) in a greenhouse setting, and (3) Validate the greenhouse study results using a simulated field study. Results indicate that the success of a phytoremediation design could be assessed upfront by predicting the exchangeable lead fraction in a given soil type based on its properties. Greenhouse column experiments indicated that EDDS was effective in mobilizing lead from paint-contaminated soils. Simulated field experiments showed that EDDS applications increased lead solubility, enhanced uptake by vetiver, and promoted translocation root to shoot. Results demonstrate the potential of a chemically-catalyzed phytoremediation system as a cleanup method for lead-contaminated residential soils.