Ethylenediaminedisuccinic Acid (EDDS) Enhances Phytoextraction of Lead by Veviver Grass From Paint Contaminated Residential Soils: A Field Study.

Phytoextraction is a green remediation technology for cleaning up contaminated soils. Application of chelating agents to soil increases metal solubility and therefore enhances phytoextraction.  A field study is being conducted to elucidate the efficiency of environment-friendly, biodegradable chelating agent; namely, ethylenediaminedisuccinic acid (EDDS) on phytoextraction of lead (Pb) by vetiver grass from lead-based paint contaminated residential soils. Lead-based paint contaminated soils were collected from residential properties in Baltimore, MD and San Antonio, TX.  Baltimore soils were acidic whereas San Antonio soils were alkaline.  Three soils from each city that had Pb content between 1000 and 2400 mg/kg were chosen for the field study. Field experiments were set up in San Antonio, TX and Stockton, NJ, in custom made wooden panels loaded with 5 inches of uncontaminated play sand and 5 inches of lead contaminated soil.  Vetiver grass was transplanted and allowed to grow in the wooden panels for 75 days before the first application of 10 mmol EDDS/kg soil.  Plant, soil and leachate samples were collected before and after (on day 10) the application of EDDS solution. Vetiver grass in the wooden panels was harvested on 10^th day after EDDS application. The results show that the first EDDS application significantly enhanced the phytoextraction of lead from acidic and alkaline contaminated soils.   In addition, EDDS also enhanced the translocation of Pb from root to shoot. Based on the results after the first season, it is clear that EDDS applications enhance the uptake of lead from contaminated soil by vetiver grass, without any toxic effects on the plant.