Biochar materials originated from sewage sludge may contain elevated levels of potentially toxic elements. There was a lack of information on the mobility of biochar-borne elements, as driven by low-molecular-weight organic acids (LMWOAs) contained in plant root exudates. A batch experiment was conducted to examine the effects of three common LMWOAs on the release of major elements and trace elements with a focus on various potentially toxic trace elements. The results showed that substantial amounts of Al, Mn, Fe, K, Na and Mg were extracted from two sewage sludge-derived biochar materials by the LMWOAs. A much higher release rate of potentially toxic trace elements was observed in the presence of LMWOAs, as compared to reported data using extractants not encountered in root exudates. The LMWOA-driven releasibility of various potentially toxic trace elements was in the following decreasing order: Zn > Ni > Pb > Cu > Cr >Co = Cd. Other trace elements that are subject to mobilization in the presence of LMWOAs included B, Ba, In, Li and Sr except Ba under oxalic acid extraction. Among the three LMWOAs, oxalic acid showed a generally stronger capacity to mobilize these metals. The findings obtained from this study provides new information that can be used for better evaluating the phyto-availability of trace elements bound to sewage sludge-originated biochar materials.

来自污水污泥的生物炭材料可能含有较高含量的潜在有毒元素。由于植物根系分泌物中所含的低分子量有机酸（LMWOA）的驱动，缺乏有关生物炭载元素的迁移性的信息。进行了批处理实验，以检查三种常见LMWOA对主要元素和痕量元素释放的影响，重点是各种潜在有毒的痕量元素。结果表明，LMWOAs从两种污泥来源的生物炭材料中提取了大量的Al，Mn，Fe，K，Na和Mg。与使用根系分泌物中未遇到的萃取剂的报道数据相比，在存在LMTOA的情况下，观察到潜在毒性微量元素的释放速率高得多。LMWOA驱动的各种潜在有毒微量元素的释放性按以下降序排列：Zn> Ni> Pb> Cu> Cr> Co = Cd。在LMWOA存在下需要动员的其他微量元素包括B，Ba，In，Li和Sr（草酸萃取下的Ba除外）。在这三种低分子轻金属中，草酸普遍具有较强的动员这些金属的能力。从这项研究中获得的发现提供了新的信息，可用于更好地评估与源自污泥的生物炭材料结合的微量元素的植物利用率。在这三种低分子轻金属中，草酸具有较强的动员这些金属的能力。从这项研究中获得的发现提供了新的信息，可用于更好地评估与源自污泥的生物炭材料结合的微量元素的植物利用率。在这三种低分子轻金属中，草酸具有较强的动员这些金属的能力。从这项研究中获得的发现提供了新的信息，可用于更好地评估与源自污泥的生物炭材料结合的微量元素的植物利用率。