Arsenic (As) and cadmium (Cd) are two prominent metal contaminants in mining soil, threatening food and environmental safety. The aim of this study was to explore an effective material to simultaneously reduce As and Cd uptake by plants growing in multi-contaminated soil. The effects of Fe-loaded biochar on the accumulation and translocation of As and Cd in a soil-lettuce system were investigated to evaluate the efficiency of Fe-loaded biochar in reducing As and Cd bioavailability. Application of Fe-loaded biochar at a rate of 0.5-1.5% decreased the concentrations of porewater As and Cd by 4.2-53.0% and -0.6-21.7%, respectively. The results of sequential extraction showed that Fe-loaded biochar can promote the transfer of As and Cd in soils from the available fraction to a relatively stable fraction, thus reducing the mobility and availability of As and Cd. The concentrations of As and Cd in lettuce shoots in the Fe-loaded biochar treatment were significantly decreased by 11.4-26.0% and 4.4-12.9% compared with those in the untreated soil, respectively. Fe-loaded biochar applied at a rate of 0.5-1.0% had no obvious effect on plant biomass, and the lowest weight of lettuce shoots and roots was observed in the treatment with Fe-loaded biochar applied at a rate of 1.5%, in which they were reduced by 12.9% and 18.0%, respectively. Overall, Fe-loaded biochar as a soil amendment was effective in simultaneously reducing As and Cd bioavailability in As and Cd co-contaminated soils, and an application rate lower than 1.5% is recommended to avoid significant decreases in plant growth.

中文翻译：

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载铁生物炭对采矿污染土壤中生菜砷和镉生物有效性的影响


砷 (As) 和镉 (Cd) 是矿区土壤中两种主要的金属污染物，威胁食品和环境安全。本研究的目的是探索一种有效的材料，同时减少在多重污染土壤中生长的植物对砷和镉的吸收。研究了载铁生物炭对土壤-生菜系统中砷和镉的积累和转运的影响，以评价载铁生物炭降低砷和镉生物有效性的效率。以0.5-1.5%的比例施用载铁生物炭可使孔隙水中As和Cd的浓度分别降低4.2-53.0%和-0.6-21.7%。顺序提取结果表明，负载Fe的生物炭可以促进土壤中As和Cd从有效组分向相对稳定组分的转移，从而降低As和Cd的迁移率和有效性。与未处理土壤相比，负载铁生物炭处理的生菜地上部As和Cd浓度分别显着降低了11.4-26.0%和4.4-12.9%。施用量为0.5%~1.0%的载铁生物炭对植物生物量没有明显影响，施用量为1.5%的载铁生物炭处理生菜地上部和根的重量最低，其中分别减少12.9%和18.0%。总体而言，负载铁的生物炭作为土壤改良剂可有效同时降低砷和镉共污染土壤中砷和镉的生物有效性，建议施用量低于1.5%，以避免植物生长显着下降。