Phytoremediation potential evaluation of multiple Salix clones for heavy metals (Cd, Zn and Pb) in flooded soils

Climate-induced flooding makes soil more vulnerable to heavy metal contamination, posing challenges for soil remediation. Salix has the potential to cope with flooding sums and environmental contamination, but its effectiveness in flooded soils with multiple heavy metals has not yet been well assessed. Thus, the present work tested fifteen Salix clones grown in multimetal (Cd, Zn and Pb) contaminated soils under non-flooded versus flooded conditions. The results indicated that all tasted Salix clones withstood long-term (90 d) flooding. Compared to the non-flooded condition, the flooded condition reduced the Cd (11.7-90.1%) contents in all organs but dramatically increased the Zn and Pb contents in the roots. The bioconcentration factor values of heavy metals in the aboveground organs were in the order of Cd > Zn > Pb. The tested Salix clones were characterized by high phytoextraction capacity for Cd and Zn under non-flooded condition and phytostabilization trait for Pb under flooded condition. To assess the overall performance of phytoremediation potentials, we attempted to use an analytic hierarchy process-entropy weight (AHP-EW) model, which considered the growth performance, photosynthetic parameters, accumulation, and mobility of toxic metals. Three Salix clones (J1010, P54 and P667) exhibited significant potential for multimetal remediation capacities. The current study provided valuable insights into the phytomanagement of woody plants, and the AHP-EW model is helpful for screening suitable trees for the phytoremediation of heavily multimetal contaminated wetlands.

Automated summary

Climate-induced flooding can make soil prone to heavy metal contamination, affecting soil remediation efforts. This study found that Salix clones have the potential to cope with flooding and environmental contamination, with certain clones showing significant remediation capacities for multiple heavy metals. An AHP-EW model was utilized to comprehensively evaluate the phytoremediation potentials of different Salix clones in heavily multimetal contaminated wetlands.