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

Abstract

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.

Moving towards Biofuels and High-Value Products through Phytoremediation and Biocatalytic Processes

“…These plants, accumulate high level of HMs in harvestable above-ground structures [58] that can reach concentrations up to 1000-fold higher than those of common plants and range from 10,000 ppm for Zn and Mn to 1000 for Co, Cr, Ni, Pb and Cu and to 100 for Cd and Se and 10 for Hg [58,59]. Unlike hyperaccumulators, which have a low grow rate and limited biomass production, fast-growing species, such as Z. mays, N. tabacum, H. annuus, S. bicolor and C. sativa [18,34,36,40,41,60], can also be very effective when decontaminating polluted sites. This is due to the high amounts of produced biomass, which compensate for the low concentration of metals translocated in the aerial parts.…”