Abstract

This study quantifies the potential of Eichhornia crassipes for the phytoremediation of water bodies contaminated by artisanal gold mining in Côte d’Ivoire. The initial concentrations of heavy metals in water largely exceed World Health Organisation standards: Zn=1.40±0.07 mg/l, Pb=0.86±0.04 mg/l, Cu=0.56±0.03 mg/l, Cd=0.12±0.01 mg/l, Hg=0.03±0.00 mg/l. After 6 w, bioaccumulation reached 242.9±12.5 mg/kg (Zn), 162.7±8.2 mg/kg (Pb), 155.8±7.9 mg/kg (Cu), 62.1±3.1 mg/kg (Cd), and 3.34±0.2 mg/kg (Hg), with linear correlation coefficients R2>0.99. Fitting to the pseudo-second order model revealed equilibrium capacities (qe) of 661.66±25.3 mg/g (Zn), 442.95±20.1 mg/g (Pb), 424.30±18.6 mg/g (Cu), 169.36±7.9 mg/g (Cd), and 9.09±0.6 mg/g (Hg). The global accumulation index revealed the hierarchy: Zn (54.1)>Cu (44.1)>Cd (43.1)>Pb (38.9)â?«Hg (20.0), confirming the strong affinity for Zn and Cu, while Hg remained poorly bioavailable. These results demonstrate the key role of Eichhornia crassipes as a fast heavy metal remover, provided it is used in a confined and controlled way to avoid its invasive spread.