Citation: Osman, H.E.; Fadhlallah, R.S.; Alamoudi, W.M.; Eid, E.M.; Abdelhafez, A.A. Phytoremediation Potential of Sorghum as a Bioenergy Crop in Pb-Amendment Soil. Sustainability 2023, 15, 2178. https:// doi.org/10.3390/su15032178 Academic Editor: Teodor Rusu Received: 25 December 2022 Revised: 14 January 2023 Accepted: 17 January 2023 Published: 24 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Phytoremediation Potential of Sorghum as a Bioenergy Crop in Pb-Amendment Soil Hanan E. Osman 1,2, *, Ruwaydah S. Fadhlallah 1 , Wael M. Alamoudi 1 , Ebrahem M. Eid 3,4 and Ahmed A. Abdelhafez 5,6 1 Department of Biology, Faculty of Applied Science, Umm Al-Qura University, Mecca 24382, Saudi Arabia 2 Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11649, Egypt 3 Biology Department, College of Science, King Khalid University, Abha 61321, Saudi Arabia 4 Botany Department, Faculty of Science, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt 5 Department of Soils and Water, Faculty of Agriculture, New Valley University, Kharga Oasis 72511, Egypt 6 National Committee of Soil Science, Academy of Scientific Research and Technology, Cairo 11694, Egypt * Correspondence: heosman@uqu.edu.sa Abstract: Lead contamination is among the most significant threats to the environment. The phytoex- traction 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 exper- iment 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, contamina- tion 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. Keywords: sorghum; lead; phytoremediation; tolerance index; bioenergy crop; prediction modeling 1. Introduction Soil is a valuable ecosystem that provides water, energy, nutrients and organic matter, all of which are necessary for the continued existence of a wide variety of organisms [1,2]. Due to unmanaged development, excessive amounts of potentially toxic elements (PTEs) are released into the environment [3]. Metal lead (Pb) is extremely toxic to humans. Inhal- ing or ingesting even trace amounts of lead is extremely harmful to human health [4–7]. Anthropogenic activities, such as battery recycling, mining, coal burning, pesticides, Pb- based paints, automobile exhaust and leather tanning, contribute to remarkable levels of Pb in the environment [8,9]. Alloway [10] observed a Pb concentration ranging from 2–300 g/kg in unpolluted soil, with a level of 100 g/kg being a concern to both the environ- ment and humans. Reclamation of Pb-polluted soil is difficult due to its limited mobility, high toxicity, non-biodegradability and persistent nature [11–13]. As a result, scientists, policymakers and the general public throughout the world are increasingly concerned about Pb negative impacts on the environment. For the remediation of PTEs-polluted Sustainability 2023, 15, 2178. https://doi.org/10.3390/su15032178 https://www.mdpi.com/journal/sustainability