Enhanced As, Pb and Zn Uptake by Helianthus annuus from a Heavily Contaminated Mining Soil Amended with EDTA and Olive Mill Wastewater Due to Increased Element Mobilization, as Verified by Sequential Extraction Schemes

Soils close to former mines or metallurgical facilities often contain extreme concentrations of potentially toxic elements (PTEs), and among soil remediation actions needed, enhanced phytoextraction techniques using chelating agents could be a very promising option. In this context, pot experiment was conducted evaluate the effect Na2-EDTA, olive mill wastewater (OMW), their combination (EDTA + OMW) on As, Pb Zn uptake by Helianthus annuus (sunflower), grown in heavily contaminated from Lavrio, Greece. After harvest, aboveground belowground biomass were determined. Additionally, composite samples all treatments subjected appropriate sequential extraction procedures for each PTE. Results showed that although nonstatistically significant effects plant growth As concentration observed, increased EDTA addition, alone combined with OMW. When total bioavailability parameter assessed, treatment also found significantly enhance (50% increase, p ≤ 0.05). These results further supported respective schemes which both corresponding more soluble fractions, probably as an outcome partial Fe–Mn amorphous oxide dissolution. Our study thus suggests applied EDTA, OMW application play key role reductive enhancing mobility these PTEs environment, triggering H. annuus.