(341c) Phytoremediation of Cr-Contaminated Soil: Use of Chelators in Cr Phytoextraction

In the age of industrialization and developmental progress, technological advancements have contributed to the challenge of environmental contamination of organic and inorganic pollutants. Moreover, contamination of heavy metals is considered one of the most critical threats to the soil, the environment, human health, and water resources. There are many conventional remedial methods used for environmental contaminants, though costly and often not efficient. Consequently, phytoremediation is an environmentally friendly and cost-effective way to clean up the environment of contaminants using plants. Nonetheless, the concept of using plants to remediate the environment of contaminants is not a new technology as Hartman (1975) indicated that phytoremediation was used about 300 years ago for wastewater treatment. Therefore, research has been conducted on many inorganic metals, e.g., iron (Fe), lead (Pb), zinc (Zn), and copper (Cu), using plant species but only sparse research has been performed on the heavy metal chromium (Cr⁶⁺). Moreover, hexavalent chromium is not an essential element for plants therefore, specific uptake mechanisms for Cr⁶⁺ have not been developed. Consequently, this research investigates the use of phytoextraction to remove Cr⁶⁺ from contaminated soil and the study is being conducted in three scenarios - a controlled greenhouse environment, a rooftop field setting and on a contaminated site in central Alabama. Thus, research results indicate that the use of plant species brassica kaber (wild mustard), thlaspi caerulescens (pennycress), and cyperus esculentus L. (yellow nutsedge)) alone statistically improve contaminant removal of Cr⁶⁺. Moreover, this study enhanced the uptake process with the use of amendments, such as, ethylene diamine disuccinic acid (EDDS), citric acid (C₆H₈O₇) and ethylene diamine tetraacetic acid (EDTA), which have indicated that plant species statistically removed greater contamination than that conducted with the use of no amendments.

Reference

Hartman, W.J., Jr. 1975. An Evaluation of Land Treatment of Municipal Wastewater and Physical Siting of Facility Installations. U.S. Department of Army, Washington, DC.