Illegal gold mining in Côte d’Ivoire has severely contaminated aquatic ecosystems with heavy metals, threatening environmental and human health. This study experimentally evaluated the bioaccumulation capacity of Eichhornia crassipes for six metals (Pb, Cd, Zn, Cu, As, and Hg) under controlled pH and exposure conditions. Microcosm experiments revealed maximum metal uptake at pH 6.03, with bioaccumulation factors exceeding 1 for all metals, confirming the phytoremediation potential of the plant. Temporal analysis revealed rapid adsorption during the first four weeks, followed by saturation, with pseudo-second-order kinetic models providing the best fit (R² > 0.98). The adsorption isotherms fitted the Langmuir model for Pb, Zn, and Cu, indicating monolayer chemisorption with maximum capacities of 384.6 mg.kg-1 (Pb), 529.3 mg.kg-1 (Zn), and 185.9 mg.kg-1 (Cu). The thermodynamic parameters (ΔG° 0, and ΔS° > 0) demonstrated that metal adsorption was spontaneous, endothermic, and favored at higher temperatures. Principal Component Analysis explained 92% of the total variance, grouping Pb, Cd, Zn, and Cu together, whereas As and Hg exhibited distinct behaviors. Overall, Eichhornia crassipes represents a low-cost, eco-friendly solution for remediating mining-polluted waters in developing countries.
Camille et al. (Thu,) studied this question.