2026-12-07, 17:00–18:00 (Europe/Athens), Basement (Foyer)
Phytoremediation offers a sustainable approach for remediating heavy metal-contaminated soils through strategies that either enhance metal uptake (phytoextraction) or reduce metal mobility (phytostabilization). This study evaluated the influence of metal bioavailability on phytoremediation outcomes in an acidic boreal forest soil (pH =5.6) using chelator-assisted phytoextraction and biochar-assisted phytostabilization. A 10-week greenhouse experiment was conducted on moderately contaminated soil using Indian mustard (Brassica juncea) and six chelator treatments: control, EDTA, citric acid (CA), oxalic acid (OA), and combinations of EDTA with CA or OA at rates of 3 mmol kg⁻¹ for natural chelators and 1.5 mmol kg⁻¹ EDTA in combined treatments. EDTA significantly increased the solubility of Cd, Cu, and Zn in soil and pore water; however, severe phytotoxicity resulted in plant mortality when EDTA was applied alone or in combination with natural chelators. In contrast, CA and OA caused no phytotoxicity but produced only limited increases in metal bioavailability and phytoextraction. A second three-month growth chamber experiment evaluated biochar (BC) and H2O2-modified biochar (HBC) applied at 5% (w/w) to a higher heavy metal-contaminated soil using Canada wild rye (Elymus canadensis), little bluestem (Schizachyrium scoparium), and switchgrass (Panicum virgatum). Biochar amendments improved plant growth, reduced metal accumulation in plant tissues, and enhanced metal stability. In BC-amended soils, Canada wild rye produced the highest biomass and reduced shoot Cd, Cu, and Zn concentrations by up to 81%, 77%, and 84%, respectively. Results demonstrate that metal bioavailability is a key factor governing phytoremediation success in acidic boreal soils. While chelator amendments increased metal solubility, excessive mobilization caused phytotoxicity and limited phytoextraction. Conversely, biochar reduced metal availability, enhanced plant growth, and improved metal stability, highlighting the importance of balancing metal availability with plant tolerance during phytoremediation.
Dr. Darshani Kumaragamage is a Professor at the Department of Environmental Studies and Sciences, University of Winnipeg, Canada. Her research interests include sustainable soil management and mitigating the environmental impacts of fertilizers and animal manure under different climatic and management scenarios. She has an active research program at the University of Winnipeg focusing on reducing phosphorus loadings to Lake Winnipeg and other water bodies through better agricultural management practices.
Dr. Srimathie Indraratne is an Assistant Professor in the Department of Environmental Studies and Sciences at the University of Winnipeg. Her research focuses on soil and water quality, contaminant remediation, trace metal dynamics, and sustainable soil management. She investigates the use of biochar, soil amendments, and phytoremediation approaches to reduce environmental risks associated with contaminated soils and waters.