Control of lead polluted leachate in a boxscale phytoremediation test using common buckwheat (Fagopyrum esculentum Moench) grown on lead contaminated soil

The remediation of heavy metal contaminated soil using plants is a technology worth developing. However, the overall effect of phytoremediation in high-density Pb polluted sites remains unknown. Especially, little information is available about the effects of using plants to control lead polluted leachate. Thus, we investigated the control of leachate in a box-scale phytoremediation test using common buckwheat, a Pb hyperaccumulator, grown on Pb contaminated soil. In the presence of buckwheat, the change in volumetric water content was smaller than that of the control with rainfall. The total amount of Pb in the leachate strongly correlated with the amount of leachate and the decrease in the density of Pb in the leachate. During the cultivation period, the total amount of Pb leached in the control was 1.28mg per container, while in the presence of buckwheat the total amount of Pb was approximately 22.7% of the control. Moreover, with buckwheat cultivation, Pb polluted leachate resulting from rainwater was prevented. The results suggested that buckwheat was a Pb hyperaccumulator and also had a high ability for phytostabilization. Control of Pb polluted leachate using buckwheat was shown to be a phytoremediation technology applicable to heavily Pb contaminated sites.