The biological dissolution of jarosite accelerates As mobilization in acid mine drainage environments, which can be influenced by coexisting metals. However, few studies have focused on the effects of coexisting Pb on this biogeochemical process. Here, we investigated the behavior of As during the reductive dissolution of Pb-As jarosite (PbFe3(SO4, AsO4)2(OH)6) by a sulfate-reducing bacterium (SRB) of Desulfovibrio desulfuricans. Pb incorporation inhibited jarosite dissolution and As mobilization. One reason was that Pb incorporation caused lattice distortion of jarosite, decreasing its solubility. Another reason was that S2− produced via anaerobic respiration of D. desulfuricans was partially captured by Pb2+ to form PbS, which negatively affected the reduction of Fe3+ in jarosite to aqueous Fe2+, slowing down the reductive dissolution of Pb-As jarosite and As release. Furthermore, the dissolved As5+ was reduced and quickly precipitated by forming As2S3 or being absorbed on the formed amorphous secondary minerals, resulting in only trace amounts of As being retained in the aqueous environment. Transcriptomic analysis provided additional evidence for As reduction, sulfate reduction, and extracellular electron transfer mediated by SRB. These findings offered new sights for understanding the geochemical cycling of As in acid mine drainage, and provided a reference basis for the treatment of Pb and As co-contaminated environment.

中文翻译：

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Pb 减轻 Pb-As 黄石生物还原溶解过程中的 As 动员


黄铁矿的生物溶解加速了酸性矿山排水环境中的 As 动员，这可能受到共存金属的影响。然而，很少有研究关注共存 Pb 对这种生物地球化学过程的影响。在这里，我们研究了 Pb-As 黄铁矿 （PbFe3（SO4， AsO4）2（OH）6） 被脱硫菌的硫酸盐还原菌 （SRB） 还原溶解过程中 As 的行为。Pb 掺入抑制黄石溶解和 As 动员。一个原因是 Pb 掺入导致黄铁矿的晶格变形，从而降低其溶解度。另一个原因是脱硫石檀厌氧呼吸产生的 S2− 被 Pb2+ 部分捕获形成 PbS，这对黄铁矿中 Fe3+ 的还原为水 Fe2+ 产生了负面影响，减缓了 Pb-As 黄铁矿的还原溶解和 As 的释放。此外，溶解的 As5+ 通过形成 As2S3 或被形成的无定形次生矿物吸收而被还原并迅速沉淀，导致仅微量的 As 保留在水环境中。转录组学分析为 SRB 介导的 As 还原、硫酸盐还原和细胞外电子转移提供了更多证据。这些发现为理解酸性矿山排水中As的地球化学循环提供了新的思路，为Pb和As共污染环境的处理提供了参考依据。