Phytoremediation Potential of Sorghum as a Bioenergy Crop in Pb-Amendment Soil

Lead contamination is among the most significant threats to the environment. The phytoextraction approach uses plants that can tolerate and accumulate metals in their tissues. Lately, biofuel plants have been recommended to be suitable for remediation and implementation of potentially toxic elements (PTEs)-polluted soil. This research assessed the Pb phytoremediation potential of three Sorghum bicolor [red cultivar (S1), white cultivar (S2) and shahla cultivar (S3)]. A pot experiment with five treatments (0, 100, 200, 400 and 800 mg Pb/kg soil) was carried out to assess the potential possibility of using these cultivars to remediate the soil of Pb. The potential possibility of using these plants to phytoremediate the soil of Pb was also assessed. The results emphasized that all the examined cultivars could attain growth to maturity in high Pb spiked soil. However, Pb influenced morphological and chlorophyll contents, especially in plants grown in soil amended with 800 mg/kg. The S1 cultivar had the most significant reduction in total chlorophyll with an average of 72%, followed by the S2 and S3 cultivars (65% and 58% reduction, respectively). The highest Pb content in root (110.0, 177.6 and 198.9 mg/kg, respectively) and in-plant shoot (83.9, 103.6 and 99.0 mg/kg, respectively) were detected by sorghum (S1, S2 and S3, respectively) grown in soil enriched by 800 mg/kg of Pb. From the calculated results of the contamination indices, contamination factor (CF), translocation factor (TF), plant uptake (UT) and tolerance index (TI), none of the investigated cultivars were considered Pb hyperaccumulators, but all were identified as particularly ideal for phytostabilization.

Automated summary

Lead contamination poses a significant threat to the environment, and the phytoextraction approach using tolerant and metal-accumulating plants is recommended for soil remediation. This study assessed the phytoremediation potential of three Sorghum bicolor cultivars (S1, S2, and S3) for lead-contaminated soil. The results showed that all cultivars could grow to maturity in high lead soil, but lead affected their morphology and chlorophyll contents, especially at 800 mg/kg. None of the cultivars were considered lead hyperaccumulators, but they were identified as suitable for phytostabilization.