Comparative Analysis of Phytoremediation Potential of Selected Indigenous Nigerian Plants for Lead-Contaminated Soils from Mining Areas in Ebonyi State

Phytoremediation offers a cost-effective and ecologically compatible approach to rehabilitating heavy metal-contaminated soils at mine sites, yet the phytoextraction potential of indigenous Nigerian plant species for lead-contaminated soils has not been systematically evaluated. This study comparatively analyses the phytoextraction potential of five indigenous plant species for lead removal from soils collected from lead-zinc mine sites in Ebonyi State, South East Nigeria. Greenhouse pot experiments were designed using three contamination levels of mine-derived soil and five plant species: Vetiveria zizanioides, Tithonia diversifolia, Chromolaena odorata, Eleusine indica, and Axonopus compressus. After 60-day growth periods, above-ground and root biomass were harvested and analysed for lead content by flame atomic absorption spectrometry. Bioconcentration factors, translocation factors, and total lead removal per pot were calculated. Results indicate that Tithonia diversifolia and Vetiveria zizanioides achieve bioconcentration factors above 1.0 at moderate soil lead concentrations, qualifying them as hyperaccumulators under the experimental conditions tested. Total lead extraction per season for Tithonia diversifolia is estimated at 2.8 kilograms per hectare at 1,500 milligrams per kilogram soil lead concentration. The study identifies soil pH adjustment with organic amendments as a significant enhancement measure. Recommendations include field-scale pilot trials and development of a multi-species phytoremediation protocol for South East Nigerian mining sites. Keywords: phytoremediation, lead contamination, indigenous plants, Ebonyi State, mine rehabilitation.