Scholarly record

THE USE OF OXYGEN TREES IN THE SOIL AND WATER ENVIRONMENT TREATMENT

Dominika Dabrowska

Abstract

The generation of leachates containing heavy metals, salts, and organic contaminants like polycyclic aromatic hydrocarbons (PAHs) makes municipal solid waste landfills a major contributor to soil and water degradation. Because traditional remediation techniques are often cost-prohibitive, sustainable approaches such as phytoremediation have gained considerable attention. This research investigates the efficacy of Paulownia tomentosa (Oxytree) in restoring soils impacted by landfill leachates. In a controlled greenhouse experiment, seedlings were subjected to three irrigation treatments: distilled water (control), 50% leachate concentration, and 100% leachate concentration. Subsequent chemical assessments of the soil and plant tissues (roots, stems, and leaves) demonstrated that the plant selectively absorbed macronutrients, notably nitrogen and phosphorus, alongside specific potentially toxic elements like copper, zinc, and lead. Crucially, these contaminants were predominantly sequestered within the root system. The application of leachates induced measurable physiological stress in the plants, evidenced by a rise in proline concentrations and a concurrent decline in flavonoid and phenol levels, which are key stress biomarkers. Interestingly, P. tomentosa showed a capacity to degrade 4- and 5-ring PAHs, with the most significant reductions occurring under moderate (50%) leachate exposure. Despite these capabilities, the overall phytoremediation performance of Paulownia was found to be inferior when contrasted with specialized phytoremediation grasses, which display a more robust ability to extract contaminants. Ultimately, the findings suggest that P. tomentosa has limited practical application for landfill remediation unless leachate concentrations are carefully managed and optimized.

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