Soil–plant interactions and metal uptake efficiency of native species in phosphate mining-affected environments

BACKGROUND: Wild plant species serve as significant models for evaluating the effects of anthropogenic activities on terrestrial ecosystems. In recent years, phytoremediation has garnered significant attention as a sustainable approach to remediate metal-contaminated soils, due to its ability to maintain soil structure while facilitating potential metal recovery. This study assessed the phytoremediation capabilities of seven indigenous wild plant species in soils impacted by phosphate mining operations. METHODS: Metal concentrations in soil and plant samples were measured by atomic spectroscopy. Ten biologically distinct rhizosphere soil samples were collected for each of the seven wild plant species; each biological replicate was made up of pooled material from five individual plants. The effectiveness of phytoremediation was evaluated by computing the Biological Accumulation Coefficient (BAC), Bioaccumulation Factor (BF), Element Accumulation Index (EAI), and Translocation Factor (TF) for selected trace metals. RESULTS AND DISCUSSION: Metal bioavailability was significantly associated with soil pH and organic matter content. The concentration of soil macronutrients was low. The bioconcentration factor exceeded one for most tested elements. Mn and Zn in Bidens pilosa and Conyza bonariensis were the sole exceptions. All metals except Mn had biological accumulation coefficients greater than 1. TF values suggested variable translocation potential among the studied plant species. CONCLUSION: The results indicate that the examined native plant species can tolerate elevated metal concentrations and sequester them, thereby endorsing their potential application in the remediation of phosphate-mining-affected metal-contaminated soils.