Chemically Catalyzed Phytoextraction for Sustainable Cleanup of Soil Lead Contamination in a Community Garden in Jersey City, New Jersey

Abstract

Soil lead (Pb) contamination in Pb paint-contaminated homes is a serious health risk in urban areas. Phytoextraction is a green and sustainable technology for soil Pb remediation, but its efficiency depends on the geochemical partitioning of Pb in soil. Following successful laboratory, greenhouse, and panel experiments, a field study was conducted to demonstrate the effectiveness of a chemically catalyzed phytoextraction model for Pb removal. A biodegradable chelating agent, ethylenediaminedisuccinic acid (EDDS) was applied during Pb phytoextraction by vetiver grass (Chrysopogon zizanioides) in a Pb-contaminated community garden in Jersey City, New Jersey. Results showed that soil Pb concentration was reduced from 1144 to 359 mg/kg in 3 years, despite ongoing Pb input to the field plots from a nearby construction site. EDDS was effective in converting non-plant-available forms of Pb (i.e., carbonate-bound, oxide-bound, and organic-bound forms) to plant-available forms (i.e., water-soluble and exchangeable forms). With EDDS application, vetiver roots accumulated 532, 231, and 401 mg/kg of Pb in Years 1, 2, and 3, respectively, which were higher than the values obtained without EDDS applications (228, 154, and 214 mg/kg). This field study demonstrated the effectiveness of a chemically catalyzed phytoextraction model for Pb removal from urban soils.