Optimization of Phytoremediation of Lead-contaminated Soil by Spinach (Spinacia oleracea L)

Phytoremediation is a plant process that cleans polluted environments. This study investigates the phytoremediation of lead-contaminated soil by spinach. The plants were transplanted into pots that contain 7 kg of lead-contaminated soil. The response surface methodology and central composite design were used to clarify the nature of the response surface in the experimental plan and determine the optimum settings of the independent variables and their responses. The independent factors were the different concentrations of lead in the soil at 250, 500, and 750 mg/Kg. Each pot had 2, 4, and 6 spinach plants, and the growth periods were 7, 14, and 21 days, respectively. The results showed that spinach has good potential to act as a phytoremediator in lead-contaminated soil. Lead accumulated more in shoots than in roots. At the optimum conditions for the concentration of lead in soil (283.31 mg/Kg), the number of planted spinach in each pot (six plants), and the time when samples are taken (20.89 d), the removal efficiency of lead was 60.05%.