Potential of enhancing the phytoremediation efficiency of Solanum nigrum L. by earthworms.

Contamination of the soil by Cadmium (Cd) is emerged as a critical environmental problem in China due to current urbanization and industrial activities that hinder the sustainable future development of agriculture. In this study, a system combined by earthworm and Solanum nigrum L. (S. nigurm) was designed for remediation of Cadmium from contaminated soils. The present study revealed that application of earthworm enhanced the biomass of S. nigrum by 61.71%, maxim; the Cd concentrations in the aboveground part of S. nigrum enhanced 35.8% when 50 g earthworm was added into each pot; the addition of earthworm also have some effect on the bio-concentration factor (BF) of S. nigrum while no effect was detected on the bio-transfer factor (TF). In addition, considering the accumulation of Cd by earthworm, the total amount of Cd extracted by the combined system enhanced 57.7% at least and 264.6% at the most, compared to the Cd extraction amount of S. nigrum alone. Generally, according to this study, the earthworm-S. nigrum system has the potential to be used for the remediation of Cd contaminated soils.