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Understanding the Environmental Impact of a Mine Dam Rupture in Brazil: Prospects for Remediation
Author(s) -
Santos O. S. H.,
Avellar F. C.,
Alves M.,
Trindade R. C.,
Menezes M. B.,
Ferreira M. C.,
França G. S.,
Cordeiro J.,
Sobreira F. G.,
Yoshida I. M.,
Moura P. M.,
Baptista M. B.,
Scotti M. R.
Publication year - 2019
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2018.04.0168
Subject(s) - tailings , environmental remediation , sediment , environmental chemistry , environmental science , nutrient , organic matter , deposition (geology) , riparian zone , arsenic , biota , biomass (ecology) , environmental engineering , chemistry , geology , contamination , ecology , paleontology , organic chemistry , habitat , biology , oceanography
The rupture of the Fundão mine dam in Mariana municipality, Minas Gerais State, Brazil, spilled the tailings across the Doce River basin. These tailings, composed of residues discarded from the beneficiation of iron ore, are rich in SiO 2 and Al 2 O 3 , as well as some ether amine compounds and NaOH. The aim of this study was to assess the distribution of these sediments, as well as their effect on the riparian zones reached, as compared with preserved sites. Sediment deposition in the river resulted in a morphological change from a meandering profile to a braided aspect. The nutrient and mineral content (P, K, Ca, Mg, Cu, Fe, Mn, Zn, and NO 3 − ) and soil organic matter of the sediments were depleted, whereas NH 4 + , Na, and pH increased. A random presence of ether amines in the sediments was confirmed by quantitative and chromatographic analyses, with concentrations ranging from 0 to 57.8 mg kg −1 ; Na reached values as high as 150 mg kg −1 . The impact of the dam tailings on biota was assessed by estimating total microbial biomass (phospholipid fatty acids), which were depleted in sediments relative to soils from preserved sites. Overall plant mortality, as well as a low resilience capacity, were also observed. Ether amines and Na present in the sediments had a strong toxic effect in the environment. Identification of these substances as the main impact factors will help guide future remediation efforts. Core Ideas Dam disruption caused changes in the fluvial profile and nutrient depletion in the sediment. Depletion of microbial biomass in the sediment and plant mortality occurred. Despite the low organic matter and NO 3 − in the sediment, NH 4 + , Na, and pH increased. The environmental impact was attributed to the increase in NH 4 + , pH, and Na. Ether amine and Na from the dam are the main toxic factors.