Kamal Asif, Nazish Moona, Kamal Khalid, Akbar Mahnoor, Ansir Faseeha, Aslam Nawaira, Riaz Muhammad Sohail, Albasher Gadah, Munis Muhammad Farooq Hussain
Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
National Center of Excellence in Physical Chemistry, University of Peshawar, 25120, KPK, Pakistan.
Sci Rep. 2025 Aug 1;15(1):28099. doi: 10.1038/s41598-025-13759-w.
The use of microbial loaded biochar in soil remediation is becoming popular worldwide. In the current research, a maize straw biochar (MB) and Trichoderma harzianum loaded biochar (MBT) were used at various rates in Cd-Cu dual polluted soil, to see their effect on Cd-Cu removal and to explore vigorous changes of metals bio-accessibility. Throughout the 90 days of remediation experiment, the dynamic impacts on the soil's physiochemical characteristics were noted. According to the current study's findings, applying 5% MBT to the soil early in the incubation period significantly raised its pH, which eventually dropped to a neutral-alkaline level. The application of MBT promoted residual bound Cu-Cd fraction and decreased carbonate and exchangeable bound fraction in the treated soil. The exchangeable portion of Cd highly decreased by 15.33% in the MBT5 amendments. Similarly, the DTPA extractable Cu and Cd concentration (i.e., DTPA-Cu, DTPA-Cd) in the amended soil gradually decreased with time. After 90 days, the DTPA-Cd contents lowered from 45 mg kg in CT to 25.3 mg kg in MBT5 whereas the DTPA-Cu concentration was 62.3 mg kg in MBT5, respectively. The Cd bio-accessibility of gastric juice was reduced in all treatments including 68.1% of MBT5. Gastrointestinal fractions at the various treatments were recorded to be 73% (MB1), 71.1% (MBT1), 67.4% (MB5), and 63.5% (MBT5). In comparison, an obvious reduction in Cu bio-accessibility was perceived in all four amendments, viz. MB1 (72.5%), MBT1 (69.6%), MB5 (65.1%), and MB5 (61.4%) in gastric solution. The addition of MBT also enhanced soil enzymatic activity particularly urease and catalase, in the later phase of the experiment, showing the retrieval function of soil for the post-stabilization of metal. The present study confirmed that MBT effectively reduces Cd and Cu bio-accessibility and mobility, supporting long term soil stabilization. It also restores soil enzymatic activity, making it a sustainable and ecofriendly approach for heavy metal remediation.
负载微生物的生物炭在土壤修复中的应用正在全球范围内受到欢迎。在当前研究中，将玉米秸秆生物炭（MB）和哈茨木霉负载生物炭（MBT）以不同比例施用于镉 - 铜双重污染土壤中，以观察它们对镉 - 铜去除的影响，并探究金属生物可利用性的剧烈变化。在整个90天的修复实验过程中，记录了对土壤理化特性的动态影响。根据当前研究结果，在培养期早期向土壤中施用5%的MBT可显著提高其pH值，最终降至中性 - 碱性水平。MBT的施用促进了处理后土壤中残留结合态铜 - 镉组分的增加，并降低了碳酸盐结合态和可交换态结合组分。在MBT5处理中，镉的可交换部分大幅降低了15.33%。同样，改良土壤中DTPA可提取的铜和镉浓度（即DTPA - Cu、DTPA - Cd）随时间逐渐降低。90天后，DTPA - Cd含量从对照处理（CT）中的45 mg/kg降至MBT5处理中的25.3 mg/kg，而MBT5处理中DTPA - Cu浓度分别为62.3 mg/kg。在所有处理中，包括MBT5处理中68.1%的镉，胃液中镉的生物可利用性均降低。记录到不同处理的胃肠道组分分别为73%（MB1）、71.1%（MBT1）、67.4%（MB5）和63.5%（MBT5）。相比之下，在所有四种改良处理中，即胃溶液中的MB1（72.5%）、MBT1（69.6%）、MB5（65.1%）和MBT5（61.4%），铜的生物可利用性均明显降低。在实验后期，MBT的添加还增强了土壤酶活性，特别是脲酶和过氧化氢酶，显示出土壤对金属后稳定化的恢复功能。本研究证实，MBT有效地降低了镉和铜的生物可利用性和迁移性，支持长期土壤稳定化。它还恢复了土壤酶活性，使其成为一种可持续且生态友好的重金属修复方法。
