Nano-hydroxyapatite immobilized lead and enhanced plant growth of ryegrass in a contaminated soil

• Nano-hydroxyapatite (NHAP) enhanced the biomass of ryegrass.
• NHAP has a good potential as immobilization in remediation technology of Pb.
• Ryegrass plus NHAP, the leaves extracted greater amounts of Pb in polluted soil.

Lead (Pb) is one of the ubiquitous soil contaminants. The strategy to increase Pb phytoremediation is of highly critical considering the difficulty in phytoextraction of Pb due to its low solubility and high retention on soil particles. The effects of application nano hydroxyapatite (NHAP) on Pb phytoextraction by ryegrass (Lolium Perenne L.) were evaluated. Ninety pots of Pb-contaminated soil with different Pb concentrations (0–800 mg/kg) were seeded with ryegrass. The effects of NHAP on biomass and Pb uptake were examined. The results indicated that the application of 5 g/kg NHAP to Pb-contaminated soils significantly increased the ryegrass biomass. The removal rates of Pb from the soil by ryegrass were enhanced obviously after NHAP addition. These results suggested that NHAP was suitable for application to in-situ Pb-contaminated soils for remediation. The observation in this study provides useful information about the effects of NHAP on lead removal, which plays an important role in the phytoremediation.

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