The concentration of 14 potentially toxic elements (PTE), including emerging contaminants, was determined in mine tunnel sludges, streambed sediments, and in the bank-full channel load of the Baccatoio stream, in Tuscany (Italy), in a catchment affected by AMD. The geochemical profile of streambed piston-cored sediments and the solute concentrations of the hyporheic pore water and surface water were also determined. Sediments are characterized by high concentrations of As, Cd, Tl, Sb, Ni, Cu, Zn, besides Al, Mn, and Fe. The As and Fe are closely coupled, indicating that iron oxyhydroxide precipitation plays a major role in controlling As sequestration. Mn oxides likely act as a sorbent for Zn, Ni, Sb, and Pb. Downstream geochemical trends indicate that precipitation and sorption represent the natural attenuation processes controlling the PTE loading released from the contaminated acidic effluents. The obtained results highlight that the Baccatoio stream sediments may act as secondary pollution sources via redox cycling, allowing contaminant remobilization to surface- and ground-water across the streambed, affecting the stream environment and aquatic biota.

14 种潜在有毒元素 (PTE) 的浓度，包括新出现的污染物，在矿山隧道淤泥、河床沉积物和 Baccatoio 河的全河道负载中测定，在托斯卡纳（意大利），受 AMD 影响的集水区. 还测定了河床活塞岩心沉积物的地球化学剖面和下流孔隙水和地表水的溶质浓度。沉积物的特征是高浓度的 As、Cd、Tl、Sb、Ni、Cu、Zn，除了 Al、Mn 和 Fe。As 和 Fe 紧密耦合，表明氢氧化铁沉淀在控制 As 螯合中起主要作用。Mn 氧化物可能充当 Zn、Ni、Sb 和 Pb 的吸附剂。下游地球化学趋势表明，沉淀和吸附代表了控制从受污染酸性流出物中释放的 PTE 负载的自然衰减过程。获得的结果强调，Baccatoio 河流沉积物可能通过氧化还原循环作为二次污染源，使污染物重新迁移到跨河床的地表和地下水，影响河流环境和水生生物群。