The potential of selected ornamental plants for remediating heavy metal-contaminated soil: A case study at the Zenica Steel Mill, Bosnia and Herzegovin

In this study, a greenhouse experiment was carried out from April to July 2024 to assess the effectiveness of four ornamental plants in removing heavy metals from the polluted soil surrounding the Zenica steel mill in Bosnia and Herzegovina. The selected ornamental plants - blue mink (Ageratum houstonianum Mill.), marigold (Tagetes erecta L.), impatiens (Impatiens walleriana Hook. f.), and begonia (Begonia semperflorens - Cultorum Group) - demonstrated potential for addressing soil contamination. These plants were cultivated in grow bags filled with soil collected from different areas surrounding the Zenica steel mill. The concentrations of heavy metals (Cu, Zn, Pb, Cd, Cr, Mn, and Fe) in both soil and plant samples were analyzed using atomic absorption spectrophotometry. The findings of this study reveal that soils adjacent to the Zenica steel mill are heavilycontaminated with Zn, Cd, and Pb and also contain notable levels of Mn and Fe. The bioaccumulation factor (BAF) and translocation factor (TF) were calculated to determine the potential of the selected ornamental plants to uptake and transport heavy metals from the soil to its aboveground parts. The BAF values for all heavy metals in all studied plant species were consistently below 1, indicating a limited capacity to remove heavy metals from the soil. This limited effectiveness can be attributed, among other factors, to the high pH levels of the tested soils. Despite the limitation, the findings revealed a significant difference in the plants’ capacity to uptake and accumulate heavy metal ions from the examined soils. Among the tested plants, blue mink demonstrated the highest ability to absorb Cu, Pb, Cr and Fe, while the highest concentrations of Zn and Cd were found in begonia