The phytostabilization of mine tailings requires a previous assessment of the effects of soil amendments on metal mobility. The goal of this work was to evaluate the response of metal availability (both labile and potentially available pools) to the addition of two organic amendments (a municipal waste biosolid and a tree biochar), separately and in combination, in a mine tailings substrate. For this purpose, a comprehensive comparison among several single extraction procedures and a sequential extraction procedure was performed. The effects on metals phytotoxicity were assessed through a germination test using seeds of Zygophyllum fabago. When evaluating the effect of the amendments in the labile metal pool, the biochar resulted effective in decreasing metal-extractable concentrations, especially for Cd, Mn and Zn. The treatment with biochar also showed better germination parameters (percentage of germinated seeds and sooner germination) than the rest of the unamended and amended treatments. The use of the municipal organic biosolid increased labile metal concentrations and potentially available metal pools assessed with EDTA and did not contribute to achieve better results of seed germination. Compared to the single biosolid treatment, the combination of biochar/biosolid modulated some labile metal concentrations and showed similar germination parameters to those obtained for the treatment amended only with biochar. This positive effect of biochar in modulating the soluble metal concentrations associated with certain urban/agricultural organic materials supported the suitability of using these combinations in field applications, although a higher rate of biochar application would be recommended to obtain a more beneficial effect.

尾矿的植物稳定需要事先评估土壤改良剂对金属流动性的影响。这项工作的目的是评估金属可用性（不稳定的和潜在的可用池）对添加两种有机改良剂（城市垃圾生物固体和树木生物炭）的响应，分别和组合，在尾矿基质中。为此，对几种单一提取程序和顺序提取程序进行了综合比较。通过使用Zygophyllum fabago种子的发芽试验评估对金属植物毒性的影响. 在评估不稳定金属池中的修正效果时，生物炭可有效降低金属可萃取物的浓度，尤其是对 Cd、Mn 和 Zn。与其他未修改和修改的处理相比，使用生物炭的处理也显示出更好的发芽参数（发芽种子的百分比和更快的发芽）。使用市政有机生物固体增加了不稳定金属浓度和潜在可用的金属池，用 EDTA 评估，并没有有助于实现更好的种子发芽结果。与单一的生物固体处理相比，生物炭/生物固体的组合调节了一些不稳定的金属浓度，并显示出与仅用生物炭修正的处理获得的相似的发芽参数。