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First Report of Field Remediation of Contaminated Tailings from the Collapsed Fundão Dam in Brazil



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Proceedings of the 5th World Congress on New Technologies (NewTech'19)
Lisbon, Portugal August, 2019
Paper No. ICEPR 163
DOI: 10.11159/icepr19.163
ICEPR 163-1
First Report of Field Remediation of Contaminated Tailings from the
Collapsed Fundão Dam in Brazil
Maria Rita Scotti1, Stephania S Avila1, Leonardo Mendes1, Tomas. J. Lacerda1, Samuel Lourenço L.
Silva1, Arthur C Antão1, Alessandra R. F Gomes1, Mirelli B Medeiros2, Stael Alvarenga2, Carlos
Henrique B Santos3, Everlon C Rigobelo3
1Depto de Botânica/ICB/UFMG
Av Antonio Carlos 6627, Belo Horizonte, Brasil
2Escola de Arquitetura /UFMG Programa Pós Graduação em Ambiente Construído e Patrimônio Sustentável
Av Antonio Carlos 6627, Belo Horizonte, Brasil.
3Dept. Produção Vegetal/ Universidade do Estado de São Paulo /Unesp
Via Professor Paulo Donato Castelane Castellane S/N - Vila Industrial, 14884-900 Jaboticabal, Brasil.
Abstract- The failure of the Fundão dam in Brazil spilled contaminated sediments to the Doce river basin with high levels of
pH,ether-amine and sodium. In the present study, it was established a riparian forest over contaminated sediment using two main
remediation strategies: phytoremediation with native species to the Atlantic Forest, previously selected for tolerance to the sediment
toxicity, and physico-chemical remediation by management of the sediment with incorporation of OM. In the experimental site (ES),
12 native species were cultivated under two treatments: T1- management of the sediments with incorporation of OM and T2- non-
managed sediment + superficial deposition of OM. The results were compared with a degraded site (DS) affected by the contaminated
sediments and a preserved site (PS) composed of a fragment of preserved Atlantic Forest. After 6 month of transplanting, plants from
T1 showed a better height growth performance (up to 3m) and survival index in relation to T2, as well as a significant decline of
ether- amine and sodium contents. Besides the improvement of soil fertility, the amendment with OM promoted a pH reduction,
favoring ether-amine destabilization, sodium sequestration and improvement of soil microbial populations. Soil nitrification was
improved as revealed by the significant increase of nitrate which seems to have favoured the rampant growth of tolerant plant species
after 6 months of planting. Therefore, it is recommended the incorporation of OM to the sediment and phytoremediation with selected
tolerant species to remediate sodium and ether-amine toxicity.
Keywords: Dam tailings, Ether-amine, Sodium, pH, Phytoremediation, Reclamation.
1. Introduction
The failure of the Fundão dam which belonged to the mining company Samarco S/A and was located in the Mariana
town (Brazil), has spread a sediment wave that reached the Doce River basin until the Atlantic Ocean, constituting the
largest environmental disaster in Brazil [1].
The main environmental impact of this dam rupture has been attributed to the elevated amounts of ether-amine and
sodium as well as the high pH found in the sediments as compared to preserved sites not reached by the tailings [2].
Ether-amines and NaOH are products that were found into the dam and derived from the Reverse Cationic Flotation
technique used in iron ore benefitiation process by Samarco mine [3,4,5]. The toxic effects of ether amines and sodium
in the reached zones [2] have been associated with plant mortality and a strong decline of microbial populations and
diversity [2,6].
Therefore, the aim of this study was to assess physico-chemical and phyto-remediation procedures to reclaim
ether-amine and sodium toxicity under field conditions.
2. Material and methods
2.1. Study site
The study sites consisted of the following riparian sites: 1- Preserved site (PS) located along the Lavras Velhas river
(20º20'313 4"S 43º17'13.61"W), 2- Degraded Site (DS) located in the Gualaxo river, reached by the dam tailings
(20º17'55.79"S 43º14'07.31"W) and a 3- Experimental Site (ES) located in the same river where the remediation
procedures were installed over a 2 m sediment layer (Fig 1).
ICEPR 163-2
2.2. Experimental design
The design of ES in a area of 1500 m2 (60 m x 25 m) was composed of 2 blocks with 2 plots/treatment (15 x 25 m)
and 2 treatment/block .The remediation treatments were: T1- Plant-derived organic matter (OM) incorporation to
scrapped sediment (top layer) and T2- intact sediment plus superficial deposition of OM. The OM used in ES was
composed of Ca: 1.28 %, P: 0.22 %, K: 2.1 %, Mg 0.3 %, N :2.1 %,C/N 24 and with pH 5. Itwas added 50 kg/plot in a
proportion of 1:4 (vv).
Each plot was cultivated with 12 Atlantic forest species, which were previously selected for tolerance to the
sediment. The plants were transplanted to the field after 4 months growing under nursery conditions with a spacing of 3
x 3 m. It was established four plots of 375 m2 (15 x 25 m) in the reference sites DS and PS.
Therefore, three remediation strategies were used: 1- Phytoremediation using selected plant species tolerant to the
sediment toxicity under green-house conditions; 2- Physico-chemical remediation by management of the sediment with
incorporation of OM to reduce ether-amine and sodium toxicity, besides lowering pH.
2.3. Soil analysis
Samples were obtained from 0 to 20 cm depth, at each study site (ES, DS and PS). In ES, 16 samples or 8 mixed
samples/treatment (2 mixed soil samples/plot/treatment x 2 treatments×4 plots) were collected 6 months after
transplantation. In DS and PS, 8 samples were collected composed of 2 mixed soil samples/plot/site x 4 plots. The soil
chemical analysis was performed according to EMBRAPA [2]. Total inorganic nitrogen was determined by semimicro-
Kjeldahl digestion [8] and ammonium and nitrate contents were determined according to Bremner and Keeney [9]. Ether-
amine quantification was performed using the colorimetric bromocresol green method [2,10]. Total microbial biomass
was determined by total phospholipid fatty acids (PLFA) analysis [2].
3. Results and Discusion
Using the sediment spilled from the dam, contaminated with ether-amines and sodium [2], we performed a screening
test, resulting in the selection of native species to the Brazilian Atlantic Forest with a varying tolerance degree, to be
tested in the field. Under field conditions, the plants showed a higher survival index in T1 (84%) than T2 (61%), and the
height growth in T1 was nearly twice that observed in T2 ( Table 1 ). Therefore, the combined treatment of sediment
scrapping associated with its mixture with plant-derived OM favored the establishment and survival of native plants in
the field, which showed an outstanding growth performance only 6 months after transplanting. The better growth
performance of native plants observed in T1 may be attributed to the greater reduction of sodium and ether-amine in
comparison to T2 and both in relation to DS (Table 2), as a consequence of the physico-chemical (sediment management
+ OM incorporation) remediation procedure.
Ether-amine concentrations reached levels as low as those from the PS as did the soil ammonium content. Such
reductions may be attributed to both the physico-chemical and phytoremediation procedures. Considering that there was
a decrease of N-ammonium concomitant with an increase of N-nitrate in ES, we may conclude that the plants may have
used the ammonium derived from ether-amine degradation [11]. Indeed, the pH reduction by the OM amendment leads
to ether-amine destabilization since the ionization of secondary and tertiary amines greatly depends on pH levels [12].
Under alkaline pH conditions (~9), ether-amine shows low dissociation capacity and solubility, while in pH~5, it becomes
dissociated and soluble in aqueous solution [11]. Therefore, the reduction of soil pH using OM amendment with pH 5
was also proposed to favor the ether-amine dissociation, increasing its availability to biodegradation [11] and further
utilization for plant growth as N source. Additionally, the OM favoured the oxidation of ammonium to nitrate by the
nitrifying microbial community since there was a marked increase of both soil microbial biomass and nitrate in ES,
especially in T1 in relation to DS. Besides, the N derived from the OM itself may be considered another source of N.
Thus, such increased nitrate levels in ES may have largely contributed to the outstanding plant growth, highlighting in
T1. Sodium levels also declined in ES, mainly in T1 but still showed significantly higher levels than PS (Table 2).
Sodium reduction may be attributed to the physico-chemical remediation procedure since the OM shows chelating
properties [13,14], whose acidic characteristics [15] improve the negative charges able to hold the Na ions. Thus, the
decrease of pH promoted by the OM amendment associated with the Na decline reinforce the idea of the Na chelating
properties of OM [13,14, 16]. In fact, there was a greater reduction of Na in T1 where the OM was incorporated to the
sediment in comparison to T2 where it was deposited in the superficial layer, thus, becoming more exposed to superficial
erosion and runoff.
The incorporation of SOM to the sediment also resulted in an overall increase in soil fertility in T1 than T2, as
determined by the increase of K, Ca, Mg and P (Table 2). Such increase in soil fertility in ES, particularly in T1, may
ICEPR 163-3
likely be attributed to the incorporation of organic matter to the topsoil, becoming it more homogeneously distributed in
a thicker sediment layer than the superficial deposition in T2. In consequence, it resulted in a reduction of nutrients losses
or a better physical contact of plant root and nutrients.
4. Conclusion
This is the first report of field remediation of contaminated sediments from the Fundão dam rupture. In other to
reclaim Na and ether-amine toxicity, we first selected tolerant plant species able to growth on the contaminated sediment.
Second, we proposed physical, chemical and phyto-remediation procedures under field conditions. The physico-chemical
remediation consisted in the incorporation of OM to the sediment which promoted pH reduction, favoring the Na decline,
ether-amine destabilization and soil fertility improvement as well as the increase of microbial communities. Under this
treatment, selected tolerant plant species showed a rampant growth only 6 months after planting.
Fig. 1: A: disturbed Site before transplantation, B: Experimental site (ES) 6 months and C: ES 12 months after transplantation.
Table 1: Survival index and height growth of plants cultivated in the experimental site (ES) under treatments 1 (ES T1) and 2 (ES-
T2). The variance of analysis (ANOVA1 was applied to compare mean differences among sites (significance at p ≤ 5%). Tukey
ICEPR 163-4
Table 2: Soil chemical analysis, ether-amine content and total microbial biomass in Experimental site (ES) uunder two
management treatment ( ES-T1 and ES-T2) as compared to preserved (PS) and disturbed (DS).sites . The variance of analysis
(ANOVA1 was applied to compare mean differences among sites (significance at p ≤ 5%). Tukey test.
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biomass -
C ( nmol/
2,30 b
... Metals in the sediments were registered at the same levels as preserved sites not affected by the dam tailings [2] and the regional background, both before [6] and after [7] the disaster. Despite the great impact of these contaminants over such a vast area [2], [8], [9] were able to establish a pioneer remediation model to reduce the ether-amine and sodium in a riparian area affected by contaminated sediment by using phyto-and physical-chemical co-strategies. These strategies were able to remediate and reclaim the affected site. ...
... Thus, these contaminants in the settler areas may explain the reduction of agricultural productivity by 50% and of fishing in their properties, as shown in Fig. 2 A and B, and also in reports by ANVISA (Brazilian Health Regulatory Agency) [16] . However, such toxicity may be remediated by both woody and agro-pastoral species, as shown by [8] - [9]. Such remediation strategies allowed the recovery of soil fertility and significant improvement in plant growth [9]. ...
Full-text available
On November 5, 2015 occurred the collapse of the mining tailings dam of Fundão (Mariana/MG), as well as part of the Santarém dam, both belonging to the mining company Samarco. This disruption, which flow rate was more than 55 million cubic meters of mining tailings, led to the largest environmental disaster in Brazil. Iron is the most used metal in the world, being extracted from nature in the form of iron ore. During the iron ore processing, it is usedthe reverse cationic flotation system, which occurs at alkaline pH (between 10 and 10.5). In this system, the precipitation of iron ore is promoted by the addition of starch, while the flotation of the gangue remaining material (tailing) is promoted by the addition of amines. The latter are highly corrosive and potentially toxic to biological systems. The disruption of these tailings dams has generated impacts on the quality and availability of water, on the riparian vegetation, as well as on the soil fertility and microbiota. These impacts were caused both by the accumulation of sediments, as by its toxicity (especially due to the presence of amines, which raised the soil and water pH). The impacts on the riparian vegetation can be recovered if they are used appropriate techniques of physical restraint and the correct vegetation, which must be both tolerant to the amines toxicity, as able to promote soil aggregation.
Full-text available
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 SiO2 and Al2O3, 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 NO3 −) and soil organic matter of the sediments were depleted, whereas NH4 +, 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.
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Bacteria present in effluents from the process of iron ore flotation were isolated and identified in an attempt to identify the microorganisms responsible for fatty amine degradation. Water samples collected at the tailings dam led to the identification of the bacterial species Serratia marcescens as the microorganism responsible for degradation, while in laboratory flotation conditions, a strain of Enterobacter cloacae was shown to be the biodegrading agent. Both S. marcescens and E. cloacae are Gram-negative, non-sporulated, mobile and facultative anaerobic bacteria. Monitoring of the effluent had shown that after 5 days, around 34% of amine was already consumed, increasing to 75% after 10 days; these data are important for testing the reuse of the fatty amines contained in effluents. Biodegradation experiments carried out with S. marcescens revealed the significant role of temperature and concentration on the biodegradation rate of the etheramine EDA 3B. For the concentration of 10 mg L−1, amine biodegradation rates are very close at all temperatures. However, as amine concentration increases, the influence of temperature can be better observed, mainly for concentrations of 40 and 60 mg L−1. This isolate will be potentially useful in biotreatment of wastewaters and bioremediation of contaminated soils.
Full-text available
The role of reagents utilised in iron ores flotation is reviewed. Desliming and flotation stages should be performed at pH levels as low as possible to reduce the expenses with caustic soda. Ether amines are by far the mostly utilised class of collector. The degree of neutralisation of the ether amine is an important process parameter. The partial substitution of amine by non-polar oils seems to be an attractive route. Part of the amine may be also replaced by polyglycols in its frother role. Starches still represent the most important class of iron oxides depressant. Very pure corn starch may be successfully replaced by products from the food industry containing proteins. Oil grades in the starch higher than 1.8% may act as froth inhibitors. Cassava starch may be an economically attractive option since the production capacity meets the required demand level.
On November 5th, 2015, Samarco's iron mine dam – called Fundão – spilled 50–60 million m3 of mud into Gualaxo do Norte, a river that belongs to Rio Doce Basin. Approximately 15 km2 were flooded along the rivers Gualaxo do Norte, Carmo and Doce, reaching the Atlantic Ocean on November 22nd, 2015. Six days after, our group collected mud, soil and water samples in Bento Rodrigues (Minas Gerais, Brazil), which was the first impacted area. Overall, the results, water samples – potable and surface water from river – presented chemical elements concentration according to Brazilian environmental legislations, except silver concentration in surface water that ranged from 1.5 to 1087 μg L−1. In addition, water mud-containing presented Fe and Mn concentrations approximately 4-fold higher than the maximum limit for water bodies quality assessment, according to Brazilian laws. Mud particle size ranged from 1 to 200 μm. SEM-EDS spot provided us some semi quantitative data. Leaching/extraction tests suggested that Ba, Pb, As, Sr, Fe, Mn and Al have high potential mobilization from mud to water. Low microbial diversity in mud samples compared to background soil samples. Toxicological bioassays (HepG2 and Allium cepa) indicated potential risks of cytotoxicity and DNA damage in mud and soil samples used in both assays. The present study provides preliminary information aiming to collaborate to the development of future works for monitoring and risk assessment.
Steam distillation methods of determining ammonium, nitrate, and nitrite in the presence of alkali-labile organic nitrogen compounds are described. They involve the use of magnesium oxide for distillation of ammonium, ball-milled Devarda alloy for reduction of nitrate and nitrite to ammonium, and sulfamic acid for destruction of nitrite. The methods are rapid, accurate, and precise, and they permit nitrogen isotope-ratio analysis of ammonium, nitrate, and nitrite in tracer studies using 15N-enriched compounds. They give quantitative recovery of ammonium, nitrate and nitrite added to soil and plant extracts, and appear suitable for analysis of biological materials.
Sodium leaching efficiencies (moles of Na removed per unit leachate volume) were measured and compared from four noncropped and four cropped treatments applied in duplicate to 1.0 m deep sodic calcareous silt loam in lysimeters. Treatments included a check, gypsum, chopped alfalfa (Medicago sativa L.), fresh manure, alfalfa, sorghum (Sorghum bicolor), Sudan grass (Sorghum Sudanese) hybrid (which will be called sorghum hybrid for simplicity), sorghum hybrid + leaching, and cotton (Gossypium hirsutum L.). The sorghum hybrid + leaching treatment soil was leached with tap water until 0.5 pore volume of leachate was collected from lysimeter bottoms, and then sorghum hybrid was planted. Sorghum hybrid was the most efficient treatment in reclaiming Na-affected soil. All four non-cropped soils eventually became dispersed in the lower part of the profile and hydraulic conductivity became very low. Cropped treatments continued to conduct water at a satisfactory rate for reclamation; however, due to low water use, cotton treatment produced a low total Na removal. Sorghum hybrid shows promise as a crop that could be used to speed reclamation of sodic calcareous soils. The treatments producing the highest sodium removal efficiencies also produced the highest soil atmosphere CO² concentrations. By selecting crops, amendments, and water application rates and timing, calcareous sodic soil reclamation can very likely be accomplished faster and more economically than in the past. Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © . .
Ether amine greases are commonly used in the flotation of iron ore, and after use are discarded in the tailings dams. The aim of this work was to quantify a commercial ether amine using the bromocresol green dye in chloroform. The statistical data obtained show that the method is characterized by satisfactory accuracy and precision with a detection limit below 1 mg/L. The recovery obtained was 98.53%, in average. In addition, the method presented here provided a recovery of ether amine contained in effluents and solids higher than 98%.
1. The reliability of the Kjeldahl method for the determination of nitrogen in soils has been investigated using a range of soils containing from 0·03 to 2·7% nitrogen. 2. The same result was obtained when soil was analysed by a variety of Kjeldahl procedures which included methods known to recover various forms of nitrogen not determined by Kjeldahl procedures commonly employed for soil analysis. From this and other evidence presented it is concluded that very little, if any, of the nitrogen in the soils examined was in the form of highly refractory nitrogen compounds or of compounds containing N—N or N—O linkages. 3. Results by the method of determining nitrogen in soils recommended by the Association of Official Agricultural Chemists were 10–37% lower than those obtained by other methods tested. Satisfactory results were obtained by this method when the period of digestion recommended was increased. 4. Ammonium-N fixed by clay minerals is determined by the Kjeldahl method. 5. Selenium and mercury are considerably more effective than copper for catalysis of Kjeldahl digestion of soil. Conditions leading to loss of nitrogen using selenium are defined, and difficulties encountered using mercury are discussed. 6. The most important factor in Kjeldahl analysis is the temperature of digestion with sulphuric acid, which is controlled largely by the amount of potassium (or sodium) sulphate used for digestion. 7. The period of digestion required for Kjeldahl analysis of soil depends on the concentration of potassium sulphate in the digest. When the concentration is low (e.g. 0·3 g./ml. sulphuric acid) it is necessary to digest for several hours; when it is high (e.g. 1·0 g./ml. sulphuric acid) short periods of digestion are adequate. Catalysts greatly affect the rate of digestion when the salt concentration is low, but have little effect when the salt concentration is high. 8. Nitrogen is lost during Kjeldahl analysis when the temperature of digestion exceeds about 400° C. 9. Determinations of the amounts of sulphuric acid consumed by various mineral and organic soils during Kjeldahl digestion showed that there is little risk of loss of nitrogen under the conditions usually employed for Kjeldahl digestion of soil. Acid consumption values for various soil constituents are given, from which the amounts of sulphuric acid likely to be consumed during Kjeldahl digestion of different types of soil can be calculated. 10. Semi-micro Kjeldahl methods of determining soil nitrogen gave the same results as macro-Kjeldahl methods. 11. The use of the Hoskins apparatus for the determination of ammonium is described. 12. It is concluded that the Kjeldahl method is satisfactory for the determination of nitrogen in soils provided a few simple precautions are observed. The merits and defects of different Kjeldahl procedures are discussed.