Mining activities produce waste materials and effluents with very high metal concentrations that can negatively impact ecosystems and human health. Consequently, data on soil and plant metal levels are crucial for evaluating pollution severity and formulating soil reclamation strategies, such as phytoremediation. Our research focused on soils and vegetation of a highly contaminated site with potentially toxic metals (Pb, Zn, and Cu) in the Touissit mining districts of eastern Morocco. Vegetation inventory was carried out in three mine tailings of the Touissit mine fields using the “field tower” technique. Here, 91 species belonging to 23 families were inventoried: the most represented families were Poaceae and Asteraceae, and the biological spectrum indicated a predominance of Therophytes (55.12%). From the studied areas, 15 species were selected and collected in triplicate on the tailings and sampled with their corresponding rhizospheric soils, and analyzed for Pb, Zn, and Cu concentrations. Reseda lutea, lotus marocanus, and lotus corniculatus can be considered as hyperaccumulators of Pb, as these plants accumulated more than 1000 mg·kg⁻¹ in their aerial parts. According to TF, these plant species could serve as effective plants for Pb phytoextraction.

Growing concerns over metal pollution highlight the need for effective remediation strategies. This study evaluates the accumulation capacity and tolerance of Melia azedarach and Ailanthus altissima for trace elements (Pb, Zn, and Cu), aiming to assess their phytoremediation potential. Three-month-old seedlings of both species, grown from seeds collected at the Touissit mine site, were cultivated in perlite and irrigated with Hoagland nutrient solution. Plants were exposed to various concentrations of metal salts—Pb(NO₃)₂ (8, 40, and 80 mg.L⁻¹), ZnSO₄ (8, 40, and 80 mg.L⁻¹), and CuSO₄ (2, 10, and 20 mg.L⁻¹)—over a 90-day period. Growth, biomass, metal accumulation, chlorophyll, and carotenoid contents were measured. Results indicate that M. azedarach exhibited enhanced biomass under Pb exposure, suggesting notable tolerance and potential for phytoremediation. Conversely, A. altissima showed an initial increase in biomass at low Pb levels, followed by a significant reduction at higher concentrations. Both species demonstrated decreased biomass under Zn and Cu treatments, with varying degrees of sensitivity. Notably, A. altissima accumulated significant levels of Pb, Zn, and Cu, particularly in the roots, indicating high phytoremediation potential. While M. azedarach also accumulated metals, levels were comparatively lower. Both species maintained chlorophyll content under metal stress, indicating resilience. Overall, this hydroponic screening highlights the considerable capacities of M. azedarach and A. altissima for Pb, Zn, and Cu tolerance, with A. altissima showing particularly high potential for Pb phytostabilization.

Mining activities often contaminate soils with heavy metals, generating environmental and health risks. This study investigates the ecotoxicity of muddy (Mw) and sandy (Sw) mining wastes on Phaseolus vulgaris and assesses the impact of five locally sourced biochar amendments on plant growth and soil pore water (SPW) properties. Most biochars improved water retention, except for argan nut shells (An) biochar, highlighting the importance of feedstock type. Sw supported better plant growth than Mw regardless of biochar addition, due to textural differences. Palm fronds (Pf) biochar significantly enhanced surface leaf area in Sw. SPW analysis revealed that biochar affected pH and electrical conductivity (EC) differently across soil types. Mw consistently increased pH, while Sw’s pH was biochar-dependent. A significant 5.1-fold EC increase was recorded in Sw amended with Pf. All biochars reduced Pb availability in Mw at planting, while Cu availability decreased in Sw at harvest. In Mw, Pb, Zn, and Cu, uptake and accumulation were unaffected by biochar, while a slight reduction was observed in Sw roots. A germination test with Lepidium sativum confirmed these findings, particularly the inhibition observed with An. This dual approach highlights the toxicity of mining soils and biochars’ potential as amendments for soil remediation programs.

Mining activities pose environmental challenges, particularly in the management of mine tailings. This study evaluates metal contamination in wastes generated during the retreatment of mine tailings for residual lead (Pb) recovery. Physicochemical and biological analyses were conducted on mine tailings (Mt), muddy wastes (Mw), and sandy wastes (Sw). Among the waste types, Mw exhibited the highest organic matter (7.4%) and clay content. The retreatment process led to shifts in metal concentrations, particularly for Pb, with total levels increasing in Mw (12.4 g·kg⁻¹). However, calcium chloride extraction indicated that Pb was more bioavailable in Sw (8.15 mg·kg⁻¹) than in Mw (5.88 mg·kg⁻¹). Sequential extraction analysis identified Mw as the most contaminated waste, displaying the highest exchangeable Pb (41.24%) and Cu (21.87%), while Zn mobility was similar in Mw (7.69%) and Sw (8.20%). The mobility factor (MF) further highlighted the environmental risks, with Mw exhibiting greater metal mobility. Enzymatic activity assessments indicated a decline in soil quality due to elevated metal concentrations. Plant surveys revealed that vegetation was primarily restricted to the clay-rich Mw, where species diversity was low and dominated by Asteraceae, Amaranthaceae, and Poaceae families. Metal analysis in rhizospheric soil and plant organs identified potential metal accumulators and hyperaccumulators. Bioaccumulation (BCF) and translocation (TF) factors highlighted distinct phytoremediation potentials, with Atractylis gummifera and Rhaponticum acaule emerging as promising hyperaccumulators. These findings provide valuable insights into metal speciation, soil contamination, and plant adaptation in newly generated wastes, supporting phytoremediation as a potential strategy for contaminant mitigation.