Remediation of soil polluted with Pb and Cd and alleviation of oxidative stress in Brassica rapa plant using nanoscale zerovalent iron supported with coconut-husk biochar

Moses Akintayo Aborisade; Hongzhi Geng; Belay Tafa Oba; Akash Kumar; Efomah Andrew Ndudi; Ashenafi Yohannes Battamo; Jiashu Liu; Daying Chen; Oluwaseun Princess Okimiji; Oluwasheyi Zacchaeus Ojekunle; Yongkui Yang; Peizhe Sun; Lin Zhao

doi:10.1016/j.jplph.2023.154023

Remediation of soil polluted with Pb and Cd and alleviation of oxidative stress in Brassica rapa plant using nanoscale zerovalent iron supported with coconut-husk biochar

J Plant Physiol. 2023 Aug:287:154023. doi: 10.1016/j.jplph.2023.154023. Epub 2023 Jun 15.

Affiliations

¹ School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; Tianjin Engineering Center for Technology of Protection and Function Construction of Ecological Critical Zone, Tianjin, 300072, China.
² School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
³ College of Natural Science, Arba Minch University, 21, Arba Minch, Ethiopia.
⁴ Department of Environmental Management, Faculty of Environmental Sciences, Lagos State University, PMB. 102101, Lagos State, Nigeria.
⁵ Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, P.M.B 2240, Ogun State, Nigeria.
⁶ School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; Tianjin Engineering Center for Technology of Protection and Function Construction of Ecological Critical Zone, Tianjin, 300072, China. Electronic address: zhaolin@tju.edu.cn.

PMID: 37343484
DOI: 10.1016/j.jplph.2023.154023

Abstract

Accumulation of toxic elements by plants from polluted soil can induce the excessive formation of reactive oxygen species (ROS), thereby causing retarded plants' physiological attributes. Several researchers have remediated soil using various forms of zerovalent iron; however, their residual impacts on oxidative stress indicators and health risks in leafy vegetables have not yet been investigated. In this research, nanoscale zerovalent iron supported with coconut-husk biochar (nZVI-CHB) was synthesized through carbothermal reduction process using Fe₂O₃ and coconut-husk. The stabilization effects of varying concentrations of nZVI-CHB and CHB (250 and 500 mg/kg) on cadmium (Cd) and lead (Pb) in soil were analyzed, and their effects on toxic metals induced oxidative stress, physiological properties, and antioxidant defence systems of the Brassica rapa plant were also checked. The results revealed that the immobilization of Pb and Cd in soil treated with CHB was low, leading to a higher accumulation of metals in plants grown. However, nZVI-CHB could significantly immobilize Pb (57.5-62.12%) and Cd (64.1-75.9%) in the soil, leading to their lower accumulation in plants below recommended safe limits and eventually reduced carcinogenic risk (CR) and hazard quotient (HQ) for both Pb and Cd in children and adults below the recommended tolerable range of <1 for HQ and 10^-6 - 10^-4 for CR. Also, a low dose of nZVI-CHB significantly mitigated toxic metal-induced oxidative stress in the vegetable plant by inhibiting the toxic metals uptake and increasing antioxidant enzyme activities. Thus, this study provided another insightful way of converting environmental wastes to sustainable adsorbents for soil remediation and proved that a low-dose of nZVI-CHB can effectively improve soil quality, plant physiological attributes and reduce the toxic metals exposure health risk below the tolerable range.

Keywords: Antioxidants; Brassica rapa; Health risk; ROS; Soil remediation; nZVI-supported coconut-husk biochar.