Phytoextraction of lead (Pb) by Phragmites australis (Cav.) Trin. ex Steud. (Poaceae).

Abstract

Heavy metal pollution, particularly from lead (Pb), remains one of the major environmental challenges facing society worldwide. Pb is frequently detected in surface water bodies and sediments, and its exposure can cause a range of adverse health effects in plants, animals, and humans. Therefore, the development of sustainable and cost-effective technologies to reduce Pb concentrations in aquatic systems is critically important. Phytoremediation using Phragmites australis has emerged as a promising remediation strategy. This study aimed to evaluate the phytoextraction potential of P. australis for Pb removal. Two experimental conditions were tested: natural river water (PbNW) and deionized water (PbDW), both amended with 250 mg/L of Pb (NO₃)₂. Pb accumulation was quantified in both aerial and underground plant tissues. In aerial tissues, Pb concentrations reached 26.4 ± 1.3 mg/kg (PbDW) and 1.5 ± 0.2 mg/kg (PbNW), while in under-ground tissues, concentrations were 103.4 ± 11.5 mg/kg (PbDW) and 38.9 ± 10.3 mg/kg (PbNW). Based on the translocation factor (TF) and bioconcentration factor (BCF), Pb was found to accumulate predominantly in underground tissues. Additionally, a slight increase in electrical conductivity (DW: 0.2 to 0.6; PbDW: 0.2 to 0.6; PbNW: 0.3 to 0.6 mS/cm) was observed. Pb concentrations in solution decreased during the experiment, from 227.4 to 170.1 mg/L in PbDW and from 83.95 to 4.6 mg/L in PbNW, confirming the plant's potential for Pb removal. P. australis demonstrated a significant capacity to accumulate Pb, mainly in roots and rhizomes, and was classified as a phytostabilizing species. These characteristics make it a suitable species for the restoration of sites impacted by Pb.