de Souza Rolim Glauco, Pacheco Fernando António Leal, do Valle Junior Renato Farias, de Melo Silva Maytê Maria Abreu Pires, Pissarra Teresa Cristina Tarlé, de Melo Marília Carvalho, Valera Carlos Alberto, Fernandes Luís Filipe Sanches, Moura João Paulo
School of Agricultural and Veterinary Sciences, Universidade Estadual Paulista (UNESP), Via de Acesso Prof. Paulo Donato Castellane, s/n, Jaboticabal, SP 14884-900, Brazil.
CQVR-Chemistry Center of Vila Real, University of Trás-os-Montes and Alto Douro, Ap. 1013, 5001-801 Vila Real, Portugal.
Sci Total Environ. 2024 Nov 1;949:174970. doi: 10.1016/j.scitotenv.2024.174970. Epub 2024 Jul 25.
Tailings dams' disasters begin a stage of river water contamination with no endpoint at first sight. But when the river was formerly used for public water supply and the use was suspended as consequence of a dam break, a time window for safe suspension lift must be anticipated to help water managers. The purpose of this study was to seek for that moment in the case of Brumadinho dam disaster which occurred in 2019 and injected millions of cubic meters of iron- and manganese-rich tailings into the Paraopeba River, leading to the suspension of public water supply to Belo Horizonte metropolitan region with this resource, until now. To accomplish the proposed goal, an assemblage of artificial intelligence and socio-economic development models were used to anticipate precipitation, river discharge and metal concentrations (iron, manganese) until 2033. Then, the ratios of metal concentrations between impacted and non-impacted sites were determined and values representing extreme events of river discharge were selected for further assessment. A ratio ≈1 generally indicates a similarity between impacted and non-impacted areas or, put another way, a return of impacted areas to a pre-rupture condition. Moreover, when the ratio is estimated under the influence of peak flows, then a value of ≈1 indicates a return to pre-rupture conditions under the most unfavorable hydrologic regimes, thus a safe return. So, the extreme ratios were plotted against time and fitted to a straight line with intercept-x representing the requested safe time. The results pointed to 6.57 years after the accident, while using iron as contaminant indicator, or 8.71 years when manganese was considered. Despite of being a relatively low-risk timeframe, the suspension lift should be implemented in phases and monitored for precaution of potential sporadic contamination events, while dredging of the tailings from impacted areas should continue and be accelerated.
尾矿坝灾难一开始会引发河水污染，且乍一看没有尽头。但如果这条河以前用于公共供水，且因大坝决堤而暂停使用，那么必须预估一个安全恢复供水的时间窗口，以帮助水资源管理者。本研究的目的是在2019年发生的布鲁马迪纽大坝灾难中寻找那个时间点，该灾难向帕拉奥佩巴河注入了数百万立方米富含铁和锰的尾矿，导致贝洛奥里藏特大都市区的公共供水至今仍依赖该水源。为实现预定目标，使用了人工智能和社会经济发展模型的组合来预测直到2033年的降水量、河流流量和金属浓度（铁、锰）。然后，确定受影响区域和未受影响区域之间的金属浓度比值，并选择代表河流流量极端事件的值进行进一步评估。比值≈1通常表明受影响区域和未受影响区域相似，或者换句话说，受影响区域恢复到决堤前的状态。此外，当在洪峰流量的影响下估计该比值时，≈1的值表明在最不利的水文条件下恢复到决堤前的状态，即安全恢复。因此，将极端比值与时间作图，并拟合为一条直线，其截距x代表所需的安全时间。结果表明，以铁作为污染物指标时，事故发生后6.57年；考虑锰时，则为8.71年。尽管这是一个风险相对较低的时间框架，但恢复供水应分阶段实施，并进行监测以防潜在的零星污染事件，同时应继续并加快从受影响区域疏浚尾矿。
