We investigated the effects of Fe-mining tailings of the Fundão dam on water quality, concerning physical and chemical parameters, aiming to infer the recovery process of the affected areas, and prospects of water quality in the coming years. Water quality data from the Gualaxo do Norte and Carmo rivers were evaluated in three moments: (i) before the dam rupture (1999–2000), (ii) 1 year after the rupture of the Fundão dam (2016), and (iii) after the implementation of recover mitigation activities (2017–2019). Concerning the variables evaluated, the mean concentrations of Fe and Mn were higher in the dry period, and increasing turbidity was detected in the rainy season. The turbidity, even after the recovery measures, peaked at 300 and 400 NTU in 2017 and 2019, respectively. The concentrations of dissolved Fe, Mn, and Cr, closely related to the tailings, decreased with rainfall by a dilution mechanism. Conversely, the concentrations of Cd, Al, Zn, and Cu increased in the rainy season, probably by greater erosion. The implementation of the recovery actions at the Gualaxo do Norte headwaters are helping to reduce the Mn and Fe concentrations and turbidity downriver, all associated with the Fe-mining tailings.

我们调查了丰达水坝的铁矿尾矿对水质的影响，涉及理化参数，旨在推断受影响地区的恢复过程以及未来几年的水质前景。在三个时刻评估了瓜拉索河和北卡莫河的水质数据：（i）大坝破裂前（1999-2000年），（ii）Fundão大坝破裂后一年（2016年），以及（iii）实施减灾措施之后（2017-2019年）。关于所评估的变量，在干燥时期，Fe和Mn的平均浓度较高，在雨季中发现浊度增加。即使采取了恢复措施，浊度也分别在2017年和2019年达到了300 NTU和400 NTU的峰值。溶解的Fe，Mn和Cr的浓度 与尾矿密切相关，通过稀释机制随降雨而减少。相反，在雨季，Cd，Al，Zn和Cu的浓度增加，可能是由于侵蚀加剧所致。在北瓜拉索上游源头实施的恢复行动正在帮助减少锰和铁的浓度以及浊度降低的河道，所有这些都与开采铁的尾矿有关。