Effects of microbial inoculations and surfactant levels on biologically- and chemically-assisted phytoremediation of lead-contaminated soil by maize (Zea Mays L.)

Assisted phytoremediation has been widely used for decontamination of potentially toxic elements contaminated soils. A greenhouse experiment was conducted to evaluate the effectiveness of different microbial inoculations and surfactant levels on the phytoremediation of a Pb-polluted calcareous soil by maize. The results showed that application of surfactant increased both root and shoot dry matter yields. Microbial inoculations, however, had no significant effect on the root or shoot dry matter yield. Mean Pb uptake in maize root or shoot increased only following the application of some surfactant levels. Inoculation with microorganisms significantly increased both mean Pb concentration and uptake in maize root but not in maize shoot. Application of 4mmol surfactant kg-1 along with inoculation with Priformospora indica was effective in increasing Pb phytostabilisation potential. While the application of 2mmol surfactant kg(-1) along with inoculation with Pseudomonas fluorescens was effective in increasing Pb phytoextraction potential. The fact that the values of translocation efficiencies were low in all treatments, demonstrated the low capability of maize for translocation of Pb from root to shoot. Inoculation with P. fluorescens was the most effective treatment in increasing metal micronutrient uptake. Microbial inoculation and surfactant levels enhanced Pb phytoremediation mostly through phytostabilisation of this metal by maize.