Contamination of agricultural soil with cadmium (Cd) has become a global concern because of its adverse effects on ecohealth and food safety. Soil amendment with biochar has become one of the phytotechnologies to reduce soil metal phyto-availability and its potential risks along the food chain. Biochar, derived from cocoa pod, was evaluated in soil Cd fractions (exchangeable, reducible, oxidizable, and residual) by modified Commission of the European Communities Bureau of Reference sequential extraction and its efficacy to ameliorate Cd toxicity to soil enzymes and leaf bioactive compounds. A pot experiment was conducted using Cd-spiked soil at 10 mg/kg with tomato (Solanum lycopersicum L.) at a biochar application rate of 1 and 3% (w/w) for 6 wk. The addition of biochar significantly reduced (p < 0.05) the exchangeable, reducible, and residual fractions by at least approximately 23%, with a consequential decrease in Cd root uptake and transport within tomato tissues. The activity of soil enzymes (catalase, dehydrogenase, alkaline phosphatase, and urease) was affected by Cd toxicity. However, with the exception of dehydrogenase, biochar application significantly enhanced the activity of these enzymes, especially at the 3% (w/w) rate. As for the secondary metabolites we studied, Cd toxicity was observed for glutathione, terpenoids, and total phenols. However, the biochar application rate of 1% (w/w) significantly ameliorated the effects of toxicity on the secondary metabolites. In conclusion, biochar demonstrated the potential to act as a soil amendment for Cd immobilization and thereby reduce the bioavailability of Cd in soil, mitigating food security risks. Environ Toxicol Chem 2021;40:3306–3316. © 2020 SETAC

中文翻译：

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豆荚衍生生物炭的短期老化可降低土壤镉的迁移率并改善镉对土壤酶和番茄的毒性

由于镉 (Cd) 对生态健康和食品安全的不利影响，农业土壤受到镉 (Cd) 污染已成为全球关注的问题。用生物炭进行土壤改良已成为减少土壤金属植物有效性及其沿食物链的潜在风险的植物技术之一。源自可可豆荚的生物炭通过改良的欧洲共同体参考局连续提取委员会评估了土壤 Cd 组分（可交换、可还原、可氧化和残留）及其改善 Cd 对土壤酶和叶生物活性化合物的毒性的功效。使用添加 10 mg/kg Cd 的土壤和番茄 ( Solanum lycopersicum L.) 进行盆栽实验，生物炭施用率为 1% 和 3% (w/w)，持续 6 周。生物炭的加入显着降低（p < 0.05) 可交换的、可还原的和残留的部分至少减少约 23%，随之而来的是番茄组织内 Cd 根系吸收和运输的减少。土壤酶（过氧化氢酶、脱氢酶、碱性磷酸酶和脲酶）的活性受 Cd 毒性的影响。然而，除脱氢酶外，生物炭的应用显着增强了这些酶的活性，尤其是在 3% (w/w) 的情况下。至于我们研究的次级代谢物，观察到谷胱甘肽、萜类化合物和总酚的 Cd 毒性。然而，1% (w/w) 的生物炭施用率显着改善了毒性对次级代谢产物的影响。总之，生物炭展示了作为固定 Cd 的土壤改良剂的潜力，从而降低了土壤中 Cd 的生物利用度，环境毒理学化学2021；40：3306–3316。© 2020 赛泰克