Cleaning up of heavy metals-polluted water by a terrestrial hyperaccumulator Sedum alfredii Hance

Sedum alfredii Hance is a terrestrial zinc/cadmium (Zn/Cd)-hyperaccumulating and lead (Pb)-accumulating plant. Previous studies on S. alfredii were mostly focused on its physiological mechanism of heavy metal uptake and the application in phytoextraction of metals from contaminated soils. In this study, we evaluated the application potential of S. alfredii in the cleanup of heavy metals from contaminated lake water. Our research revealed that changing pH in lake water would not make particular difference on the final accumulation amount of heavy metals, because the acidic water environment negatively affected plant growth compared with the neutral and alkaline environments, but was more conducive for heavy metal absorption and accumulation. In addition, S. alfredii showed an increase of approximately 2.2-fold in dry weight (DW) when cultured with lake water for 25 d. At the same time, it accumulated approximately 5.0 mg/kg DWof Cd and 41.4 mg/kg DWof Pb. The absorption of heavy metals was highly effective during the first 10 d of culture. Also, the quality of lake water was greatly improved after only 2-d cleanup by S. alfredii. In general, this hyperaccumulator exhibits great potential for application in the cleanup of heavy metals-polluted waters.