Journal of Environmental Management 258 (2020) 110020 0301-4797/© 2020 Elsevier Ltd. All rights reserved. Research article Role of sepiolite for cadmium (Cd) polluted soil restoration and spinach growth in wastewater irrigated agricultural soil Saqib Bashir a, b, * , Umeed Ali b , Muhammad Shaaban c , Allah Bakhsh Gulshan d , Javaid Iqbal e , Shahbaz Khan e , Arif Husain a , Niaz Ahmed c , Sajid Mehmood f , Muhammad Kamran b , Hongqing Hu b a Department of Soil & Environmental Science Ghazi University, DG Khan, Pakistan b Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China c Department of Soil Science, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan d Department of Botany, Ghazi University, DG Khan, Pakistan e Department of Agronomy, Ghazi University, DG Khan, Pakistan f Guangdong Provincial Key Laboratory for Radionuclide Pollution Control and Resources, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China A R T I C L E INFO Keywords: Sepiolite Soil restoration Cadmium immobilization Spinach Adsorption mechanism ABSTRACT Metals that contaminate soil are one of the major problems seriously affecting sustainable agriculture worldwide. Cadmium (Cd) toxicity to agricultural crops is a global problem. Mobility of Cd in contaminated soil can be minimized by the amendment of soil passivators which will ultimately reduce its movement from soil to plants. A pot study was performed to evaluate the impact of sepiolite from 1% to 5% on Cd solubility and its accumulation in spinach tissues. Soil pH, Cd fractionation, Cd accumulation in spinach tissue and Cd adsorption mechanism were determined. Results were recorded that soil pH was increased from 0.3 to 1.0 units with the increasing rate of sepiolite from 1% to 5%. Similarly, Cd contents in acid soluble phase was decreased by 42.8% and increased in residual phase by 35.8% at 5% rate, relative to control. Moreover, the significant reduction in Cd uptake by spinach shoots and roots was occurred by 26.2% and 30.6% at 5% rate, respectively. Furthermore, the maximum Cd adsorption capacity 37.35 mg g 1 was recorded at 5% rate relative to control. The analysis of FTIR, XRD and SEM also confirm the ability of sepiolite for Cd polluted soil restoration and thereby, reduces its phytoavailability in polluted soil to alleviate food security challenges. 1. Introduction In recent decades, release of wastewater from industries and urban societies pose a serious threat to soil health due to the presence of po- tential toxic elements. Direct irrigation of pre-treated wastewater to agricultural fields can lead to soil hardening, heavy metal accumulation as well as cause groundwater pollution (Sun et al., 2016). The presence of cadmium (Cd) in wastewater pose serious health risks which could cause liver disease, cancer and abdominal pain. It has persistent and non degradable nature and can easily be taken up through plants. Accumu- lation of Cd in agricultural soil can hinder the plant growth by disturbing its physiocological and morphological disorder and ultimately reduced crop yields (Bashir et al., 2018a,2018b). Spinach (Spinacia Oleracea L.) has been recognized as one of the important nutritious leafy vegetables that are widely grown in Asian countries, especially in Pakistan (Bashir et al., 2019). Khan et al. (2016) described that leafy vegetables have more potential to absorb potentially toxic elements from rhizosphere and translocate to their edible portions relative to fruits and root vegetables. Moreover, leafy vegetables are responsible for 70% of the total Cd accumulation in humans. Therefore, restoration of polluted soil is an important task to lessen its accumula- tion in edible plant tissues by reducing its bioavailability in farmlands to ensure food security (Hu et al., 2014). In past decades, several conventional techniques were applied including, excavation, land filling and soil washing but now in recent decades these techniques were ignored, due to their negative effects on * Corresponding author. Ghazi University, DG Khan, Pakistan. E-mail address: Saqibbashir416@yahoo.com (S. Bashir). Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: http://www.elsevier.com/locate/jenvman https://doi.org/10.1016/j.jenvman.2019.110020 Received 11 September 2019; Received in revised form 2 December 2019; Accepted 19 December 2019