Phytoremediation of Lead‐Contaminated Soil in the Westside of Atlanta, GA

• Published in: Geohealth Vol. 7; no. 8; pp. e2022GH000752 - n/a
• Main Authors: Yao, X., Saikawa, E., Warner, S., D’Souza, P. E., Ryan, P. B., Barr, D. B.
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01-08-2023; John Wiley and Sons Inc; American Geophysical Union (AGU)
• Subjects: Aerosols; Aerosols and Particles; Atmospheric Composition and Structure; Bioaccumulation; Bioavailability; Biogeosciences; Biomass; Bioremediation; Community Engaged Research to Action: Examples from GeoHealth; Composts; Food contamination & poisoning; Gardens & gardening; Growing season; Investigations; Landfill; Lead; Marine Pollution; Megacities and Urban Environment; Metals; Natural Hazards; Oceanography: Biological and Chemical; Oceanography: General; Paleoceanography; Phytoremediation; Plant species; Pollution: Urban and Regional; Pollution: Urban, Regional and Global; soil; Soil amendment; Soil contaminants; Soil contamination; Soil erosion; Soil remediation; Superfund; Translocation; Urban Systems; Atlanta Georgia; United States > US; soil; lead; phytoremediation
• ISSN: 2471-1403; 2471-1403
• DOI: 10.1029/2022GH000752

Phytoremediation has been explored as a cost‐effective method to remediate soil Pb contamination. A greenhouse study was conducted to evaluate the efficacy of Vigna unguiculata, Brassica pekinensis, Gomphrena globose, and Helianthus annuus for removing and immobilizing Pb in soil collected from the Westside Lead Superfund site in Atlanta. Plants were cultivated in sampled soil with a Pb concentration of 515 ± 10 mg/kg for 60 days. Soils growing H. annuus were additionally treated with ethylenediaminetetraacetic acid (EDTA) (0.1 g/kg) or compost (20% soil blend) to assess their capabilities for enhancing phytoremediation. Mean post‐phytoremediation Pb concentrations in the four plant species were 23.5, 25.7, 50.0, and 58.1 mg/kg dry weight (DW), respectively, and were substantially higher than 1.55 mg/kg DW in respective plant species grown in control soils with no Pb contamination. The highest Pb concentration, translocation factor, and biomass were found in V. unguiculate among four species without soil amendments. H. annuus treated with EDTA and compost resulted in a significant increase in the total Pb uptake and larger biomass compared to non‐treated plants, respectively. Although this study found that V. unguiculata was the best candidate for Pb accumulation and immobilization among four species, soil remediation was limited to 54 mg/kg in a growing season. We find that it is critically important to perform phytostabilization in a secure manner, since Pb bioavailability of edible plant parts implies the potential risk associated with their unintentional consumption. Efficiently and effectively remediating Pb‐contaminated soils in a low‐cost manner needs to be further studied.
Plain Language Summary
Exposure to lead can cause well‐documented adverse health effects, especially on children. Contaminated soil is a major source of lead exposure. This study investigated a potential intervention involving a remediation method of lead‐contaminated soil, called phytoremediation, using four common plants: cowpea, Chinese cabbage, globe amaranth, and sunflower. We studied the ability of these plants to either take up or stabilize lead in soil and also examined the effect of two soil amendments, including EDTA and compost, on facilitating plants to remediate soil contaminants. Results showed that cowpea was the most promising candidate for taking up and stabilizing lead in soil among four species, although one growing season was not sufficient to bring down the lead concentration to the regulatory threshold. Furthermore, cowpea and Chinese cabbage accumulated lead in their tissues and can be absorbed in the body upon ingestion, the unintentional consumption of plants grown in contaminated soil can be dangerous. We also found that the application of soil amendments could facilitate further remediation, but the remediation methods need to be performed in a safe manner and more research is needed.
Key Points
Phytoremediations using Helianthus annuus, Gomphrena globose, Brassica pekinensis, and Vigna unguiculata were evaluated
Selected plants were not able to reduce the soil Pb concentration to a regulatory standard (<400 mg/kg) in a single growing season
Phytoremediation can be enhanced with soil amendents, including EDTA and compost, which increased the lead uptake and the plant biomass