A real filed phytoremediation of multi-metals contaminated soils by selected hybrid sweet sorghum with high biomass and high accumulation ability

Abstract

Heavy metal-polluted soil is obtaining increasing global concerns. The phytoremediation is a promising technology that needs further research. This study was aiming to perform a field survey to assess the restoration and accumulation potential of five hybrid sweet sorghum species with high biomass. Those sweet sorghums were planted in three sites containing different toxic levels of Zn, Pb and Cd with one local commercial sweet sorghum as contrast sample. Plants and soils were sampled for the analysis of heavy metal concentrations. BCF and TF values showed that hybrid sweet sorghum species have higher accumulation ability than local one. Five species of hybrid sweet sorghum planted in all three sites showed no obvious toxicity symptoms, and moreover, their biomass were 12–24 times higher than that of the local one, indicating their high tolerance to heavy metals. Among them, the 9312 and G38 specimens were considered as the best-performing specimens due to their high ability to accumulate multiple metals in their shoots and roots without being affected by excessive metal contents. A reasonable disposed plan for harvested sweet sorghum after phytoremediation was proposed. The harvest sweet sorghums used for industrial ethanol and densified biofuel production could combine soil remediation with creating economic benefit. Consequently, those five hybrid sweet sorghum species, especially 9312 and G38 with high biomass production, metal accumulation ability and high tolerance against metal toxicity might have great potential in phytoremediation field.