Olumuyiwa A. Olorunyomi^1,, Simon G. Mafulul¹, Ayodeji E. Olorunyomi², Peace O. Abaya¹, Segun A. Olomu¹, Samuel Y. Gazuwa¹

Tin mining has resulted in persistent contamination of soils by potentially toxic elements (PTEs), posing significant ecological and human health risks in many mining regions of Nigeria. Native weed species that naturally colonize contaminated sites may provide a sustainable and cost-effective approach for phytoremediation. This study evaluated the phytoremediation potential of five dominant native weed species (Cyperus bipartitus, Spermacoce verticillata, Festuca rubra, Tithonia diversifolia, and Ipomoea asarifolia) growing on active mining, abandoned mining, and non-mining soils in Jos North, Plateau State, Nigeria. Rhizosphere soils and plant tissues were analyzed for Cd, Pb, Zn, As, and Ni using Atomic Absorption Spectrophotometry (AAS), while phytoremediation performance was assessed using biological accumulation coefficient (BAC), bioconcentration factor (BCF), and translocation factor (TF). Nickel had the highest mean soil concentration, followed by Cd, Zn, As, and Pb. Significant differences (p < 0.05) were observed in PTE concentrations, BAC, BCF, and TF among weed species, plant tissues, and site conditions, indicating species-specific metal uptake, accumulation, and translocation patterns. Cyperus bipartitus and control-site populations of Spermacoce verticillata, Ipomoea asarifolia, and Tithonia diversifolia exhibited notable Pb phytoextraction potential, whereas Festuca rubra, Spermacoce verticillata, and Ipomoea asarifolia demonstrated effective Zn phytoextraction in mining-impacted soils. In contrast, Festuca rubra showed Cd phytostabilization potential, while Cyperus bipartitus, Ipomoea asarifolia, and Tithonia diversifolia displayed metal-specific phytostabilization capacities for Zn, As, Ni, and Pb depending on site conditions. Principal component analysis revealed that mining activities predominantly influenced the spatial distribution of potentially toxic elements, with Ni and Pb emerging as the principal indicators of mining-derived contamination. These findings demonstrated that dominant native weeds employ diverse, site-dependent remediation strategies that enhance their adaptation to heterogeneous contamination. Overall, the identified native weed species represent promising candidates for metal-specific and multi-metal phytoremediation of mining-impacted landscapes. The study provides baseline evidence to support the selection of indigenous plants for ecological restoration, sustainable management of contaminated soils, and remediation planning in tin mining regions of Nigeria and similar tropical environments.

phytoremediation, native weed species, potentially toxic elements, tin mining, bioaccumulation, phytostabilization, phytoextraction