Assessment of selected tree species as phytoremediation agents in polluted soils

Abstract

The study investigates the ability of selected tree species to absorb heavy metals (Pb, Ni, Zn) from polluted soils. Seedlings of Adansonia digitata (P₁), Jatropha curcas (P₂), and Hildegardia barteri (P₃) were transplanted into polythene pots with soils from a dumpsite (T₁), highway (T₂), industrial area (T₃), and farmland (T₄), forming a 3x4 factorial experiment replicated five times in a Completely Randomized Block Design. Pre-sowing analysis showed T₁ and T₂ had the highest Pb and Zn concentrations, T₃ had the highest Ni, and T₄ had the lowest heavy metal concentrations. After 12 weeks, heavy metal concentrations decreased in all soils. P₁ concentrated metals in the root, P₂ in the shoot, and P₃ in various plant parts, with significant differences between species. P₂ was identified as an effective phytoextractor for Pb and Zn (TF > 1), and P₃ for Ni. All species showed potential for phytostabilization. The study concludes that these species are viable options for phytoremediation of heavy metals in contaminated soils.