The phytoremediator capacity of <i>Quercus cerris</i> L. against heavy metals contamination in the Ezer forest, Lebanon

Abstract The uncontrolled rise in heavy metal pollution due to anthropogenic activities has become a global environmental concern. Lebanon's Ezer forest, dominated by Quercus cerris L., is exposed to vehicular activity along its northern edge due to an unpaved public road and intensive recreational activities in its center. This study aimed to determine the concentrations of metals in Q. cerris leaves and soil across three distinct forest stands: S1 and S2 (polluted sites) and Ctrl (control site). Cadmium, chromium, lead, and aluminium were extracted via the wet digestion method and analyzed by Atomic Absorption Spectrometry. Additionally, hydrogen peroxide levels, the total carbohydrate and phenolic content in Q. cerris leaves, as well as the activity of antioxidant enzymes, were measured. The results revealed that Ezer forest is at risk of heavy metal contamination, with a significant increase in hydrogen peroxide levels at the polluted sites compared to the Ctrl site. The total carbohydrate and phenolic content was notably reduced at the polluted sites, while peroxidase and catalase activity increased, indicating that Q. cerris has developed adaptive mechanisms to cope with oxidative stress. National strategies to raise public awareness and reduce heavy metal contamination in the forest are urgently needed to protect the rare Q. cerris species.