Metal concentrations and biological effects from one of the largest mining disasters in the world (Brumadinho, Minas Gerais, Brazil)

Carbon footprints of tailings dams' disasters: A study in the Brumadinho region (Brazil)

Tailings dams' breaks are environmental disasters with direct and intense degradation of soil. This study analyzed the impacts of B1 tailings dam rupture occurred in the Ribeirão Ferro-Carvão watershed (Brumadinho, Brazil) in January 25, 2019. Soil organic carbon (SOC) approached environmental degradation. The analysis encompassed wetlands (high-SOC pools) located in the so-called Zones of Decreasing Destructive Capacity (DCZ5 to DCZ1) defined along the Ferro-Carvão's stream bed and banks after the disaster. Remote sensed water indices were extracted from Landsat 8 and Sentinel-2 satellite images spanning the 2017-2021 period and used to distinguish the wetlands from other land covers. The annual SOC was extracted from the MapBiomas repository inside and outside the DCZs in the same period, and assessed in the field in 2023. Before the dam collapse, the DCZs maintained stable levels of SOC, while afterwards they decreased substantially reaching minimum values in 2023. The reductions were abrupt: for example, in the DCZ3 the decrease was from 51.28 ton/ha in 2017 to 4.19 ton/ha in 2023. Besides, the SOC increased from DCZs located near to DCZs located farther from the dam site, a result attributed to differences in the percentages of clay and silt in the tailings, which also increased in the same direction. The Ferro-Carvão stream watershed as whole also experienced a slight reduction in the average SOC levels after the dam collapse, from nearly 43 ton/ha in 2017 to 38 ton/ha in 2021. This result was attributed to land use changes related with the management of tailings, namely opening of accesses to remove them from the stream valley, creation of spaces for temporary deposits, among others. Overall, the study highlighted the footprints of tailings dams' accidents on SOC, which affect not only the areas impacted with the mudflow but systemically the surrounding watersheds. This is noteworthy.

Rhodococcus erythropolis ATCC 4277 behavior against different metals and its potential use in waste biomining

Rhodococcus erythropolis bacterium is known for its remarkable resistance characteristics that can be useful in several biotechnological processes, such as bioremediation. However, there is scarce knowledge concerning the behavior of this strain against different metals. This study sought to investigate the behavior of R. erythropolis ATCC 4277 against the residue of chalcopyrite and e-waste to verify both resistive capacities to the metals present in these residues and their potential use for biomining processes. These tests were carried out in a stirred tank bioreactor for 48 h, at 24ºC, pH 7.0, using a total volume of 2.0 L containing 2.5% (v/v) of a bacterial pre-culture. The pulp density of chalcopyrite was 5% (w/w), and agitation and oxygen flow rates were set to 250 rpm and 1.5 LO2 min-1, respectively. On the other hand, we utilized a waste of computer printed circuit board (WPCB) with a pulp density of 10% (w/w), agitation at 400 rpm, and an oxygen flow rate of 3.0 LO2 min-1. Metal concentration analyses post-fermentation showed that R. erythropolis ATCC 4277 was able to leach about 38% of the Cu present in the chalcopyrite residue (in ~ 24 h), and 49.5% of Fe, 42.3% of Ni, 27.4% of Al, and 15% Cu present in WPCB (in ~ 24 h). In addition, the strain survived well in the environment containing such metals, demonstrating the potential of using this bacterium for waste biomining processes as well as in other processes with these metals.

Environmental pollution and human health risk due to tailings storage facilities in China

Tailings storage facilities (TSFs) represent an anthropogenic source of pollution, resulting in potential risks to both environmental integrity and human health. To date, the environmental and human health risks from TSFs in China have been under-researched. This study attempts to address this gap by developing, and geo-statistically analyzing two comprehensive databases. The first database (I) focuses on failed TSFs; we supply the statistics of environmental damages from 143 TSF failure incidents. Notably, approximately 75 % of the failure incidents involved tailings flows released into water bodies, resulting in a significant exacerbation of environmental pollution. To better inform ecological and human health risks, we present another database (II) for 147 non-failed TSFs to investigate the soil heavy metal contamination, considering 8 heavy metals. The findings reveal that (i) Cd, Pb, and Hg are the prominent pollutants across the non-failed TSF sites in China; (ii) lead‑zinc and tungsten mine tailings storage sites exhibit the most severe pollution; (iii) Pb, Cd, and Ni present noteworthy non-carcinogenic risks to human health; (iv) >85 % of TSF sites pose carcinogenic risks associated with arsenic; and (v) health risks resulting from dermal absorption surpass ingestion for the majority of heavy metals, with the exception of Pb, where ingestion presents a more pronounced route of exposure. Our study presents a comprehensive evaluation of environmental and human health risks due to TSFs, highlighting the necessity for risk assessment of >14,000 existing TSFs in China.

Histopathology and changes in the expression of metallothioneins, heat shock proteins and inducible nitric oxide synthase in Prochilodus costatus from a neotropical river contaminated by heavy metals

The most recent dam rupture in Brazil released tons of mining tailings into the upper course of the Paraopeba River, affecting this river in an unprecedented way. The present study aimed to evaluate the influence of heavy metals on Prochilodus costatus, an important commercial species in Brazil, four years after the dam colapse. To this end, biomarkers of heavy metals, oxidative stress, and environmental stress were analyzed, and histological analyses of target organs were performed. The results demonstrated critical contamination of fish from the Paraopeba River. Increased expression of Metallothioneins - MTs, Heat Shock Protein - HSP70, and inducible nitric oxide synthase - iNOS, as well as greater rates of histological changes in the liver, spleen, and gonads, were observed in P. costatus. These findings demonstrate that, despite past contamination, the metals present in mining tailings have significantly increased the contamination of the Paraopeba River basin.

Attenuation of water contamination in the Paraopeba River after the collapse of B1 tailings dam: Natural wash-off and dredging contributions

Following the B1 dam collapse at Córrego do Feijão Mine, actions were taken to address environmental damage and enhance the quality of water in the Paraopeba River. Natural processes in the river involve gradual reduction of contamination through dispersion and downstream transportation of tailings-a slow, nature-driven process. Dredging, a human intervention, aimed to expedite recovery. Hence, this study aimed to explore dredging's role in reducing contamination in the impacted Paraopeba River zone. Analysis revealed a direct link between dredging and post-collapse turbidity, though recent trends suggest a lessening impact on pre-collapse conditions. Distinct seasonal variations were observed in iron and manganese concentrations, peaking during wet seasons and displaying notable upstream-downstream disparities. An analysis of ratios (downstream/upstream) was conducted to understand and even predict the return to pre-collapse conditions. Wet season averages for iron and manganese decreased by around 90 % over time, with standard deviations reducing by about 48 % and 58 %, respectively. In the dry season, the averages decreased by over 100 %, indicating water quality improvements surpassing pre-collapse levels. Standard deviations also decreased significantly, by approximately 67 % and 79 %, respectively. Employing an exponential decay model revealed that the contribution of dredging in the dry period is negligible, but in the wet period the contribution can be estimated at 28.6 % in the case of iron and 25 % in the case of manganese. While the models performed well based on extensive data, some limitations occur in estimating dredging contribution rates. The model's sensitivity might overlook influential factors, underscoring the importance of considering sediment nature and dredged area extent in understanding water quality dynamics. Despite these potential limitations, this investigation provides crucial insights into the intricate relationship between dredging and water quality in the Paraopeba River. These findings pave the way for future studies aimed at deeper exploration and more accurate assessments of this association.

A multi-biomarker approach to verify chronic effects on Eisenia andrei earthworms exposed to tailings from one of the world's largest mining disasters

Mining is of great relevance to the global economy, but its activities are challenging due to socio-environmental impacts. In January 2019, an iron ore tailings dam collapsed in Brumadinho (Minas Gerais, Brazil) releasing 12 × 106 m3 of tailings, causing human losses and devastation around 3.13 × 106 m2 of a watershed. In this context, the present study aimed to investigate the potential toxic effects of tailings from the collapsed dam using earthworms Eisenia andrei as a model organism for terrestrial environments. An extensive set of tests was performed, including behavioral (avoidance), acute (mortality and biomass) and chronic tests, such as biomass, reproduction and cytotoxicity (viability and cell density and change in coelomocyte pattern). The physical-chemical characterization revealed a higher density of the tailings in relation to the control soil, which can result in physical changes, such as soil compaction and surface sealing. Aluminum, Ca, Fe, Hg, Mg, Mn, K, Na and P registered higher concentrations in the tailings compared to the control soil, while Total Nitrogen, Total Organic Carbon and Organic Matter were higher in the natural soil. Based on the avoidance test, an EC50 of 27.18 ± 2.83% was estimated. No lethality was observed in the acute exposure, nor variations in biomass in the acute and chronic assays. However, there was a tendency to reduce the number of juveniles in relation to cocoons in the proportions of 3125; 12.5 and 25%. Significant changes in viability, cell density and pattern of amebocytes and eleocytes were observed up to the 35th day of exposure. A multi-biomarker approach (Integrated Biological Response version 2) indicated concentration-dependent effects and attenuation of cellular changes over time. These are the first results of chronic effects on earthworms exposed to tailings from the B1 dam. Despite being conclusive, we highlight the possible heterogeneity of the tailings and the necessary care in extrapolating the results.

Understanding seasonal variations in As and Pb river fluxes and their regulatory mechanisms through monitoring data

The Doce River Basin (DRB) suffers with the adverse impacts of mining activities, due to its high level of urbanization and numerous industrial operations. In this study, we present novel insights into contaminant flow dynamics, seasonal variations, and the primary factors driving concentration levels within the region. We conducted an extensive analysis using a database sourced from the literature, which contained data on the contamination of arsenic (As) and lead (Pb) in the Doce River. Our primary aim was to investigate the patterns of As and Pb flow throughout the entire basin, their response to seasonal fluctuations, and the key parameters influencing their concentration levels. The results showed significant seasonal fluctuations in As and Pb fluxes, peaking during the rainy season. The 2015 Fundão dam breach in the DRB led to notable changes, elevating elemental concentrations, particularly As and Pb, which were subsequently transported to the Atlantic Ocean. These increased concentrations were primarily associated with iron and manganese oxides, hydroxides, and sulfates, rather than precipitation, as evidenced by regressions with low R2 values for both As (R2 = 0.07) and Pb (R2 < 0.001), concerning precipitation. The PCA analysis further supports the connection between these elements and the oxides and hydroxides of Fe and Mn. The approach employed in this study has proven to be highly effective in comprehending biogeochemical phenomena by leveraging data from the literature and could be a model for optimizing resources by capitalizing on existing information to provide valuable insights for drainage basin management, particularly during crises.

Assessment of environmental pollution and human health risks of mine tailings in soil: after dam failure of the Córrego do Feijão Mine (in Brumadinho, Brazil)

The dam failure of the Córrego do Feijão Mine (CFM) located in Minas Gerais State, Brazil, killed at least 278 people. In addition, large extensions of aquatic and terrestrial ecosystems were destroyed, directly compromising the environmental and socioeconomic quality of the region. This study assessed the pollution and human health risks of soils impacted by the tailing spill of the CFM dam, along a sample perimeter of approximately 200 km. Based on potential ecological risk and pollution load indices, the enrichments of Cd, As, Hg, Cu, Pb and Ni in soils indicated that the Brumadinho, Mário Campos, Betim and São Joaquim de Bicas municipalities were the most affected areas by the broken dam. Restorative and reparative actions must be urgently carried out in these areas. For all contaminated areas, the children's group indicated an exacerbated propensity to the development of carcinogenic and non-carcinogenic diseases, mainly through the ingestion pathway. Toxicological risk assessments, including acute, chronic and genotoxic effects, on people living and working in mining areas should be a priority for public management and mining companies to ensure effective environmental measures that do not harm human health and well-being over time.

Association between urinary concentrations of toxic metals/metalloids and oxidative stress in Brazilians living in areas affected by the Fundão dam failure

The Fundão Dam failure has been the most significant environmental disaster in Brazil. The catastrophe released large amounts of mining waste into the environment, including toxic metals/metalloids, which are recognized to induce carcinogenic effects. The urinary levels of 8-hydroxy-2'-deoxyguanosine (8OHdG), a widely accepted oxidative stress and carcinogenesis biomarker, provide a potential tool for assessing the disaster's health implications. This study investigated the association between urinary levels of some toxic metals/metalloids and 8OHdG in Brazilian individuals living in areas affected by the Fundão dam failure. Urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) were determined using inductively coupled plasma mass spectrometry, while 8OHdG was analyzed by liquid chromatography-tandem mass spectrometry. Non-parametric bootstrap regression was used to estimate the associations between the urinary levels of toxic elements and 8OHdG. The results showed that except for Hg, urinary concentrations of all metals/metalloids analyzed here exceeded the reference ranges for the Brazilian population. The regression analysis revealed that As (0.337; CI 95%: 0.203; 0.474), Cd (0.268; CI 95%: 0.036; 0.520), and Ni (0.296; CI 950.108; 0.469) were positively associated with creatinine-adjusted urinary 8OHdG levels. Associations were not found for Hg (0.0122; CI 95%: -0.155; 0.183) and Pb (0.201; CI 95%: -0.040; 0.498). The current findings suggest that high exposure to toxic metals/metalloids might increase 8OHdG levels with potential adverse health effects. This study is the first one in which the relationship between toxic metals/metalloids and oxidative stress biomarkers is investigated in populations affected by environmental disasters. Further prospective studies are necessary to monitor exposure levels and explore additional health impacts.

First assessment of atmospheric pollution by trace elements and particulate matter after a severe collapse of a tailings dam, Minas Gerais, Brazil: An insight into biomonitoring with Tillandsia usneoides and a public health dataset

In this study, samples of bromeliad Tillandsia usneoides (n = 70) were transplanted and exposed for 15 and 45 days in 35 outdoor residential areas in Brumadinho (Minas Gerais state, Brazil) after one of the most severe mining dam collapses in the world. Trace elements aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni) and zinc (Zn) were quantified by atomic absorption spectrometry. Scanning electron microscope generated surface images of T. usneoides fragments and particulate matter (PM2.5, PM10 and PM > 10). Aluminum, Fe and Mn stood out from the other elements reflecting the regional geological background. Median concentrations in mg kg-1 increased (p < 0.05) between 15 and 45 days for Cr (0.75), Cu (1.23), Fe (474) and Mn (38.1), while Hg (0.18) was higher at 15 days. The exposed-to-control ratio revealed that As and Hg increased 18.1 and 9.4-fold, respectively, not showing a pattern associated only with the most impacted sites. The PM analysis points to a possible influence of the prevailing west wind on the increase of total particles, PM2.5 and PM10 in transplant sites located to the east. Brazilian public health dataset revealed increase in cases of some cardiovascular and respiratory diseases/symptoms in Brumadinho in the year of the dam collapse (1.38 cases per 1000 inhabitants), while Belo Horizonte capital and its metropolitan region recorded 0.97 and 0.37 cases, respectively. Although many studies have been carried out to assess the consequences of the tailings dam failure, until now atmospheric pollution had not yet been evaluated. Furthermore, based on our exploratory analysis of human health dataset, epidemiological studies are required to verify possible risk factors associated with the increase in hospital admissions in the study area.

Perceptions about massive environmental impacts: a Brazilian study case

The year 2019 brought three such impacts of high socio-environmental proportions in Brazil: the dam collapse in Brumadinho, oil spills on the coast, and fires in the Amazon. We investigated the Brazilian population's perceptions of the country's overall environmental situation, the degree to which Brazilians felt affected by these impacts considering personal and social factors, and the entities they held responsible for these disasters. Through Facebook's social media networks, we disseminated structured online surveys for Brazilian citizens above 18 years. Educational background explained how much the 775 respondents felt affected by the three evaluated events. Age was an explanatory factor for the degree to which the respondents felt affected by the dam collapse, and proximity to the disasters, while income levels were for the dam collapse and the fires in the Amazon. The government, criminal activity, and private companies were considered to be the main responsible for these three impacts. This perception reflects the series of changes in the country's environmental laws and protections that threaten biodiversity and the environment.

Exploring a new approach for assessing the fate and behavior of the tailings released by the Brumadinho dam collapse (Minas Gerais, Brazil)

In 2019, the Brumadinho dam rupture released a massive amount of iron ore mining tailings into the Paraopeba River. Up to now, it remains a public health issue for the local and downstream populations. The present study aims to assess the behavior and fate of metal contamination following the disaster. Using new sampling strategies and up-to-date geochemistry tools, we show that the dissolved metal concentrations (< 0.22 µm cutoff filtration) remained low in the Paraopeba River. Although the tailings present high metal concentrations (Fe, Mn, Cd, and As), the high local background contents of metals and other previous anthropogenic contamination hamper tracing the sediment source based only on the geochemical signature. The Pb isotopic composition coupled with the metals enrichment factor of sediments and Suspended Particulate Matter (SPM) constitutes accurate proxies that trace the fate and dispersion of tailing particles downstream of the dam collapse. This approach shows that 1) The influence of the released tailing was restricted to the Paraopeba River and the Retiro Baixo reservoir, located upstream of the São Francisco River; 2) The tailings' contribution to particulate load ranged from 17 % to 88 % in the Paraopeba River; 3) Other regional anthropogenic activities also contribute to water and sediment contamination of the Paraopeba river.

Bioaccumulation and physiological traits qualify Pistia stratiotes as a suitable species for phytoremediation and bioindication of iron-contaminated water

Serious concerns have recently been raised regarding the association of Fe excess with neurodegenerative diseases in mammals and nutritional and oxidative disorders in plants. Therefore, the current study aimed to understand the physiological changes induced by Fe excess in Pistia stratiotes, a species often employed in phytoremediation studies. P. stratiotes were subjected to five concentrations of Fe: 0.038 (control), 1.0, 3.0, 5.0 and 7.0 mM. Visual symptoms of Fe-toxicity such as bronzing of leaf edges in 5.0 and 7.0 mM-grown plants were observed after 5 days. Nevertheless, no major changes were observed in photosynthesis-related parameters at this time-point. In contrast, plants growing for 10 days in high Fe concentrations showed decreased chlorophyll concentrations and lower net CO₂ assimilation rate. Notwithstanding, P. stratiotes accumulated high amounts of Fe, especially in roots (maximum of 10,000 µg g^-1 DW) and displayed a robust induction of the enzymatic antioxidant system. In conclusion, we demonstrated that P. stratiotes can be applied to clean up Fe-contaminated water, as the species displays high Fe bioaccumulation, mostly in root apoplasts, and can maintain physiological processes under Fe excess. Our results further revealed that by monitoring visual symptoms, P. stratiotes could be applied for bioindication purposes.

A partial least squares-path model of environmental degradation in the Paraopeba River, for rainy seasons after the rupture of B1 tailings dam, Brumadinho, Brazil

The present study aimed to investigate the rupture of B1 tailings dam of Córrego do Feijão mine, which drastically affected the region of Brumadinho (Minas Gerais, Brazil). The contamination of water resources reached 155.3 km from the dam site. In the river channel, high concentrations of Mn, Al, As and Fe were detected and correlated to the spillage of the tailings in the river. The presence of the tailings also affected the chlorophyll-a content in the water, as well as the reflectance of riparian forests. With the increase of metal(oid) concentrations above permitted levels, water management authorities suspended the use of Paraopeba River as resource in the impacted areas, namely the drinking water supply to the Metropolitan region of Belo Horizonte. This study aimed to evaluate possible links between tailings distribution, river water quality, and environmental degradation, which worked as latent variables in partial least squares regression models. The latent variables were represented by numerous physical and chemical parameters of water and sediment, measured four times in 22 locations during the rainy season of 2019, in addition to stream flow and to NDVI evaluated in satellite images processed daily. The modeling results suggested a relationship between river flow turbulence and increased arsenic release from sand fractions, as well as desorption of Mn from metal oxides, both representing causes of water quality reduction. They also revealed increasing iron concentrations affecting the forest NDVI (greening), which was interpreted as environmental degradation. The increase of chlorophyll-a concentrations (related with turbidity decreases), as well as the increase of river flows (responsible for dilution effects), seemed to work out as attenuators of degradation. Although applied to a specific site, our modeling approach can be transposed to equivalent dam failures and climate contexts, helping water resource management authorities to decide upon appropriate recovery solutions.

A 140-year record of environmental changes in São Sebastião, Brazil

Over the past two centuries, coastal and estuarine areas have experienced environmental stress due to rapid population growth, leading to higher demand, overexploitation, habitat transformation, and pollution, which have severe consequences on the overall ecosystem and human health. This work aims to understand historical perspectives of such environmental stress in a coastal area of São Sebastião city in the São Paulo State of Brazil, which has witnessed rapid changes in land use over the past 60-70 years. We collected eleven surface sediments and one 64 cm long core from the shallow water depth sector of the São Sebastião Channel (SSC), adjacent to the Araçá Bay region. Sediments were dominantly composed of terrestrial siliciclastic material carrying signatures of both local inputs (i.e., weathered granitic and gneissic rocks of Serra do Mar Mountain ranges) and Plata Plume sediments brought by Brazilian coastal currents. Low sediment accumulation (avg. = 0.10 cm yr^-1) between 1880 and 1947 showed a stable environment followed by an abrupt increase in sedimentation (avg. = 0.84 cm yr^-1) from 1947 to 2017. This approximate eight-fold increase in sedimentation after 1947 marked significant anthropogenic changes in the region, which is coincidental with major changes in land use through the construction of the port of São Sebastião (1930s) and BR-101 Highway (1980s). While recent surface sediments showed no pollution of heavy metals, anthropogenic Zn enrichment was found between 1880 and 2000. Zn enrichment was from the combined sources, e.g., agriculture activities, domestic sewage, and possibly Zn coated ship paints. Our study also indicates that planned future expansion of São Sebastião port may further increase the sedimentation rate in SSC and impact the ecosystem of Araçá Bay and SSC.

Analyses of colloidal, truly dissolved, and DGT-labile metal species and phosphorus in mining area surrounded by tailing dams using self-organising maps

The knowledge of size-distribution and lability of metals and nutrients in freshwater systems is important for estimation of the ecological effects of mining. However, it is still limited in several mining areas such as the Quadrilátero Ferrífero (Brazil) which was severely polluted by the collapse of the Fundão tailings dam in November 2015. In this study, results of an investigation from 2014 using a neural network named self-organising map (SO-Map) into the conditions of selected trace metals that are of particular importance to mining areas (Cr, Cu, Co, Mn, Ni, Pb, Zn) are presented. Additionally, P was considered by its high importance as a nutrient and sites later affected by the dam burst were also included by chance. Water samples were collected at six sites in dry and rainy seasons and filtered and ultrafiltered for determination of total dissolved (<0.45 μm) and truly dissolved (<1 kDa) fractions. Diffusive gradients in thin films (DGT) devices were deployed in situ for determination of the DGT-labile fraction. All data were analysed using SO-Map and Spearman's rank correlation. Phosphorus in the Carmo River occurred mainly in the truly dissolved and DGT-labile fractions. The higher amounts of this element in the river water (up to 263 μg L^-1 of total P) might be related to untreated sewage discharge. Moreover, the concentrations of other trace metals (Mn, Cu, Co, Ni, Zn) were high, even under the "natural" conditions (before the dam failure) due to natural and anthropogenic factors such as local lithology and mining.

Mineralogical Fingerprint of Iron Ore Tailings in Paraopeba River Bedload Sediments after the B1 Dam Failure in Brumadinho, MG (Brazil)

The study presents SEM-based automated mineralogy to distinguish between natural sediments and iron ore tailings deposits from the Paraopeba River, after the failure of B1 Dam in Brumadinho, Minas Gerais, Brazil. Samples were obtained from borehole cores drilled over channel bars and banks eight months after the failure. After preliminary facies description, sediments from 54 chosen intervals were subjected to density measurement, X-ray diffraction (XRD), SEM-based automated mineralogy (QEMSCAN) analysis and determination of geochemical major components. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) revealed six main mineral associations governed by different contents and ratios of quartz, kaolinite and hematite. Natural sediments are predominantly composed of mineral associations containing kaolinite, quartz and quartz + hematite with density values ranging from 2.5 to 3.3 g/cm3. Tailings deposits have density values higher than 3.5 g/cm3 and are mainly composed of hematite with occasional occurrences of kaolinite + hematite. Because of geological complexity and historical terrain occupation and usage, geochemical anomalies are common in the Paraopeba River sediments. Our data suggests that mineralogical oriented studies should precede detailed geochemical investigations, to enhance the understanding of the source of such anomalies and the environmental jeopardy associated to the occurrence. In this sense, SEM-based mineralogy has an enormous potential in environment studies.

Genomic features of a multidrug-resistant and mercury-tolerant environmental Escherichia coli recovered after a mining dam disaster in South America

Mining dam disasters contribute to the contamination of aquatic environments, impacting associated ecosystems and wildlife. A multidrug-resistant Escherichia coli strain (B2C) was isolated from a river water sample in Brazil after the Mariana mining dam disaster. The genome was sequenced using the Illumina MiSeq platform, and de novo assembled using Unicycler. Resistome, virulome, and plasmidome were predicted using bioinformatics tools. Data analysis revealed that E. coli B2C belonged to sequence type ST219 and phylogroup E. Strikingly, a broad resistome (antibiotics, hazardous heavy metals, and biocides) was predicted, including the presence of the clinically relevant bla_CTX-M-2 extended-spectrum β-lactamase (ESBL) gene, qacE∆1 efflux pump gene, and the mer (mercury resistance) operon. SNP-based analysis revealed that environmental E. coli B2C was clustered along to ESBL-negative E. coli strains of ST219 isolated between 1980 and 2021 from livestock in the United States of America. Acquisition of clinically relevant genes by ST219 seems to be a recent genetic event related to anthropogenic activities, where polluted water environments may contribute to its dissemination at the human-animal-environment interface. In addition, the presence of genes conferring resistance to heavy metals could be related to environmental pollution from mining activities. Antimicrobial resistance genes could be essential biomarkers of environmental exposure to human and mining pollution.

Validation of an Empirical Model with Risk Assessment Functionalities to Simulate and Evaluate the Tailings Dam Failure in Brumadinho

The failure of tailings dams causes ecological damage and economic loss and can cause casualties. The simulation of the tailings’ spill path in the event of tailings dam failures (TDFs) can mitigate the risk by the provision of spatial information for disaster prevention and preparedness. In order to close the gap between basic one-dimensional spill-path routing models and complex numerical models, this paper examines an empirical model based on the freely available Laharz model. The model incorporates a tailings-specific planimetric area regression from the literature to describe the spatial extent of tailings flows based on the released volume. By providing information about affected residents and infrastructure, such a model can be used for preliminary risk evaluation. The model was validated against the TDF in Brumadinho (2019) and reached hit rates of over 80%, critical success indices of approximately 60% and false alarm ratios of roughly 30%. The latter is particularly evident in the overestimation of the lower part of the tailings flow. The risk assessment identified 120 affected residents, 117 destroyed buildings (109 reported) and several kilometres of affected roads (1.9 km) and railway (2.75 km). However, the OpenStreetMap-based part of the risk assessment inherits some uncertainties to be investigated in the future.

Rupture of Brumadinho dam (Minas Gerais, Brazil): embryotoxicity in zebrafish induced by metal mixture-contaminated water

Rupture of dam B-1 at the Córrego do Feijão mine in Brumadinho, state of Minas Gerais, Brazil (25/Jan/2019) contaminated the Paraopeba River with mine waste. To identify the adverse effects of this event on public and environmental health, we conducted the Fish Embryo Acute Toxicity (FET) test (OECD No. 236). During the tests, zebrafish embryos were exposed for 144 hours to solutions containing realistic concentrations of dissolved iron and aluminum and total manganese at the following analysis points upstream or downstream of the dam: 10 km, upstream; 19.7 km, downstream, at the point where water for consumption is collected; 24.5 km, downstream, in the city of Mário Franco; and 59 km, downstream, on the border between the towns of Juatuba and Betim. Metal concentrations were taken from September 2019 report No. 53 released by IGAM. Mortality was high at all exposure points and reached 93% at the Juatuba/Betim point. We also detected lethal, sublethal and teratogenic effects, such as non-hatching, non-inflation of the swim bladder, pericardial edema and scoliosis, affecting up to 25% of embryos at the other analysis points. The results highlight the need for continuous monitoring of the water quality of the Paraopeba River.

Genomic Resources for Salminus brasiliensis

The Neotropical region bears the most diverse freshwater fish fauna on the planet and is the stage for dramatic conservation struggles. Initiatives aiming for conservation of a single emblematic fish, a flagship species, to which different onlookers relate on a cultural/personal level, holds promise towards engagement and conservation actions benefiting whole biological communities and ecosystems. Here, we present the first comprehensive genomic resources for Salminus brasiliensis, a potential flagship Neotropical species. This fish faces pressing conservation issues, as well as taxonomic uncertainty, being a main species relevant to angling and commercial fisheries. We make available 178 million Illumina paired-end reads, 90 bases long, comprising 16 Gb (≈15X coverage) of filtered data, obtained from a primary genomic library of 500-bp fragments. We present the first de novo genomic assembly for S. brasiliensis, with ∼1 Gb (N₅₀ = 10,889), as well as the coding genome annotation of 12,962 putative genes from assembled genomic fragments over 10 kb, most of which could be identified from the Ostariophysi GenBank database. We also provide a genome-wide panel for more than 80,000 predicted microsatellite loci for low-cost, fast and abundant DNA marker development for this species. A total of 47, among 52 candidates, empirically assayed microsatellites were confirmed as polymorphic in this fish. All genomic data produced for S. brasiliensis is hereby made publicly accessible. With the disclosure of these results, we intend to foster general biology studies and to provide tools to be applied immediately in conservation and aquaculture in this candidate flagship Neotropical species.

Application of Multispectral Remote Sensing for Mapping Flood-Affected Zones in the Brumadinho Mining District (Minas Gerais, Brasil)

The collapse of the tailing “Dam B1” of the Córrego do Feijão Mine (Brumadinho, Brasil) that occurred in January 2019 is considered a large socio-environmental flood-disaster where numerous people died and the local flora and fauna were seriously affected, including agricultural areas of the Paraopeba River. This study aims to map the land area affected by the flood by using multispectral satellite images. To pursue this aim, Level-2A multispectral images from the European Space Agency’s Sentinel-2 sensor were acquired before and after the tailing dam collapse in the period 2019–2021. The pre- and post-failure event analysis allowed us to evidence drastic changes in the vegetation rate, as well as in the nature of soils and surficial waters. The spectral signatures of the minerals composing the mining products allowed us to highlight the effective area covered by the flood and to investigate the evolution of land properties after the disaster. This technique opens the possibility for quickly classifying areas involved in floods, as well as obtaining significant information potentially useful for monitoring and planning the reclamation and restoration activities in similar cases worldwide, representing an additional tool for evaluating the environmental issues related to mining operations in large areas at high temporal resolution.

Marine fish assemblages of Eastern Brazil: An update after the world's largest mining disaster and suggestions of functional groups for biomonitoring long-lasting effects

When the Fundão dam collapsed in Brazil, 50 million m³ of iron ore tailings were released into the Doce river, resulting in the world's largest mining disaster. The contaminated mud was transported 668 km downstream of the Doce river and reached the Atlantic Ocean 17 days after the collapse. Seven months later, there was evidence that the tailings had reached the largest and richest coral reef formation in the South Atlantic Ocean. This study provides the first description of species composition, abundance, and diversity patterns of fish assemblages in estuaries, coastal areas, and coral reefs affected by the rupture of the mining dam in the Doce river. A linear mixed model (GLMM) was used to evaluate the influence of salinity on fish abundance across estuarine and coastal ecosystems. In addition, based on functional traits related to habitat use and feeding habits, this study identified fish species suitable as bioindicators of the long-lasting effects of this major mining disaster. Bottom trawls were used to sample five estuaries and their respective coastal areas, and a visual census was employed to sample five reef areas, representing an impact gradient. A total of 269 species were recorded in all three habitats, but only seven were shared among them. The results showed lower similarity in assemblages among estuarine areas compared to the coastal and reef areas. Species composition among estuaries and reef ecosystems was more heterogeneous. In contrast, coastal habitats exhibited high homogeneity. Salinity had no statistically significant effect on fish abundance either in estuaries (p = 0.22) and along the coast (p = 0.14). Twelve fish species were identified as suitable bioindicators for evaluating the long-lasting effects of resuspension of contaminated sediments. These species are commonly found in the ecosystems under the influence of the disaster inhabiting potentially contaminated substrates and substrate-associated benthic preys.

Temporal and spatial variations in metals and arsenic contamination in water, sediment and biota of freshwater, marine and coastal environments after the Fundão dam failure

Temporal and spatial variabilities in concentrations of metals (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) and metalloid (As) associated with the Fundão dam tailings were evaluated in water, sediment and biota from freshwater (tributary, river, lakes and lagoons), marine and coastal (mangroves and beaches) ecosystems affected by the Mariana dam disaster (southeastern Brazil). In freshwater shrimps and fishes, temporal increases in the concentrations of most elements analyzed were observed. This finding was clearly associated with temporal increases in the concentrations of As and metals observed in both water and sediment. In turn, freshwater plankton showed only a temporal increase in Hg concentration, which was also associated with an increased concentration of this metal in the abiotic matrices. In marine fishes, temporal increases were only observed for Cu, Fe and Pb concentrations. Also, temporal increase was observed for Fe concentration in marine plankton (phytoplankton and zooplankton) and shrimps. Marine phytoplankton also showed a temporal increase in Hg concentration. All these findings were clearly associated with temporal increases in the concentrations of these metals in marine sediments. Mangrove crabs showed temporal increases in Hg and Cd, which were associated with temporal increases in water Hg and sediment Cd concentrations, respectively. In turn, beach crabs displayed temporal increases in Mn and Zn, which were associated with temporal increases in the concentrations of these metals in sediments, especially for Mn. In summary, all environmental matrices evaluated in the present study were shown to be contaminated with metals and metalloid associated with the Fundão dam tailings. Additionally, findings reported in the present study relative to the spatial variabilities observed in the whole aquatic area affected by the Fundão dam failure clearly reinforce the need of incorporating biological diversity in monitoring programs aiming to assess environmental health of aquatic systems, considering that patterns of metals and metalloid contamination levels may vary among taxa.

Laboratory profile after mining dam breach: Brumadinho Health Project results

ABSTRACT Objective: To evaluate changes in selected laboratory tests in the population included in the Brumadinho Health Project, according to the exposure to the dam failure. Methods: Cross-sectional study carried out on representative sample of residents (≥12 years) in Brumadinho, Minas Gerais, including: 1) non-exposed; 2) directly affected by tailings sludge; 3) residents in mining area. The prevalence of abnormal results of blood count, total, HDL and LDL cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, creatinine, urea, estimate of glomerular filtration rate (eGFR) and high-sensitivity C-reactive protein (hs-CRP) were estimated. The Prevalence Ratios (PR) and 95% Confidence Intervals (95%CI) of having an abnormal laboratory finding were estimated using Generalized Linear Models with Poisson probability distribution. Crude and adjusted models were estimated for age range, gender, diabetes, body mass index, smoking, hypertension. Results: After adjusting, there was no difference in PR between the three populations for most tests, with the exception of the population residing in an area with mining activity and not directly affected by the mud, with a lower chance of having altered total cholesterol (PR: 0.84; 95%CI 0.74–0.95) and a higher chance of having altered HDL cholesterol (PR: 1.26; 95%CI 1.07–1.50), hs-CRP (PR: 1.19; 95%CI 1.04–1.37), and eGFR <60mL/min/1,73 m2 (PR: 1.51; 95%CI 1.05–2.19). Conclusion: No significant differences were found in the prevalence of biochemical and hematological alterations between the populations directly exposed and not exposed to tailings. Only the group residing in the mining area had a higher prevalence of alterations related dyslipidemia, renal disease, and inflammation.

Perfil laboratorial após rompimento de barragem de mineração: resultados do Projeto Saúde Brumadinho

RESUMO Objetivo: Avaliar alterações em parâmetros laboratoriais na população do Projeto Saúde Brumadinho, segundo exposição ao rompimento da barragem. Métodos: Estudo transversal realizado em amostra representativa de residentes (≥12 anos) em Brumadinho, Minas Gerais, incluindo: não expostos (grupo referência); diretamente atingidos pela lama de rejeitos; e residentes em área de mineração. Foram estimadas as prevalências de resultados alterados de hemograma, colesterol total, colesterol lipoproteína de alta densidade (HDL), colesterol lipoproteína de baixa densidade (LDL), triglicérides, aspartato aminotransferase, alanina aminotransferase, creatinina, ureia, estimativa da taxa de filtração glomerular (TFGe) e proteína C-reativa ultrassensível (PCRus). As razões de prevalência (RP) e os intervalos de confiança de 95% (IC95%) de ter o exame alterado foram estimados por meio de modelos lineares generalizados com distribuição de probabilidade Poisson. Estimaram-se modelos brutos e ajustados por faixa etária, sexo, diabetes, índice de massa corporal, tabagismo, hipertensão. Resultados: Após ajustes, não se observou diferença nas RP entre as populações estudadas para a maioria dos testes, com exceção da população residente em área com atividade de mineração e não diretamente atingida pela lama, com menor chance de ter colesterol total alterado (RP=0,84; IC95% 0,74–0,95) e maior chance de ter colesterol HDL (RP=1,26; IC95% 1,07–1,50) e PCRus (RP=1,19; IC95% 1,04–1,37) alterado e TFGe<60 mL/min/1,73 m2 (RP=1,51; IC95% 1,05–2,19). Conclusão: Não foram encontradas diferenças significativas na prevalência de alterações bioquímicas e hematológicas entre a população diretamente exposta aos rejeitos e a população não exposta. Apenas o grupo residente em área de mineração apresentou maior prevalência de alterações relacionadas com dislipidemia, disfunção renal e inflamação.

Brumadinho Health Project: methodological aspects and epidemiological profile of participants in the cohort baseline

ABSTRACT: Objective: To present the methodological aspects of the Brumadinho Health Project and to describe the epidemiological profile of participants in the baseline cohort. Methods: Prospective, population-based cohort study in a representative sample of residents (aged 12 and over) of Brumadinho, Minas Gerais, after a mining tailings dam failure. Information for the baseline was collected in 2021, two years after the mining tailings dam collapsed, including sociodemographic, health and service use aspects, among others. Prevalence estimates of health outcomes were described in Brumadinho, as well as in the Metropolitan Region of Belo Horizonte and Minas Gerais, using data from the 2019 National Health Survey. All analyses were performed in the software Stata 17.0, considering the sampling weights and design effect. Results: 3,080 (86.4%) residents participated in the study, most of them being females (56.7%) and with a mean age of 46.1 years. The diseases more frequently reported were arterial hypertension (30.1%), high cholesterol (23.1%) and depression (22.5%), similarly to what was observed in the Metropolitan Region of Belo Horizonte and Minas Gerais, although the prevalence in Brumadinho was higher. At least one medical appointment and one hospitalization occurred in 75.2% and 9.4% of residents in the past year, respectively. Conclusion: It is important to monitor health, physical and mental conditions of residents after the occurrence of a disaster of this magnitude. This information can contribute with risk management of these processes, not only in the affected municipality, but also in other areas where populations are at risk of major disasters.

Manganese-Induced Neurotoxicity through Impairment of Cross-Talk Pathways in Human Neuroblastoma Cell Line SH-SY5Y Differentiated with Retinoic Acid

Manganese (Mn) is an important element; yet acute and/or chronic exposure to this metal has been linked to neurotoxicity and neurodegenerative illnesses such as Parkinson’s disease and others via an unknown mechanism. To better understand it, we exposed a human neuroblastoma cell model (SH-SY5Y) to two Mn chemical species, MnCl₂ and Citrate of Mn(II) (0–2000 µM), followed by a cell viability assay, transcriptomics, and bioinformatics. Even though these cells have been chemically and genetically modified, which may limit the significance of our findings, we discovered that by using RA-differentiated cells instead of undifferentiated SH-SY5Y cell line, both chemical species induce a similar toxicity, potentially governed by disruption of protein metabolism, with some differences. The MnCl₂ altered amino acid metabolism, which affects RNA metabolism and protein synthesis. Citrate of Mn(II), however, inhibited the E3 ubiquitin ligases–target protein degradation pathway, which can lead to the buildup of damaged/unfolded proteins, consistent with histone modification. Finally, we discovered that Mn(II)-induced cytotoxicity in RA-SH-SY5Y cells shared 84 percent of the pathways involved in neurodegenerative diseases.

Fifty years of articles in JEQ on trace elements in the environment and future outlook

Fifty years ago, the Journal of Environmental Quality (JEQ) was launched to provide an outlet for publication of research on the impacts of agriculture on the environment, and vice versa. A core concept of JEQ is advancement of environmental science, with emphasis on understanding factors that affect the fate, risks, and quality of soil, water, and atmospheric systems, and how these system processes affect plants, microbes, and animals. Trace elements are a focus area of JEQ because when present at higher than natural concentrations, they may pose risks to environmental quality and ecosystem health, depending on their bioavailability. Trace element biogeochemical cycling is affected by anthropogenic influences on land, air, and water, including land management practices such as agriculture and mining. The Journal of Environmental Quality has published a prolific catalog of scientific research publications on trace elements and their risks to humans, soil health, water quality, and the environment. In this review, research on trace elements and their impacts on environmental quality is presented, with a special focus on work published in JEQ.

Mining Dam Failures in Brazil: Comparing Legal Post-Disaster Decisions

Mining dam failures have increased worldwide since the 1980s. Two large mining dam failures occurred recently in Mariana and Brumadinho, both in the state of Minas Gerais, Brazil. We hypothesize that there were significant differences in legal post-disaster decisions. The aim of this article is to understand the similarities and differences of post-disaster actions and controversies in Mariana and Brumadinho. We reviewed 686 news reports about court decisions and settlement agreements from the websites of state and federal courts and judicial institutions. After classifying the reports using an adapted protocol from a media health observatory, we conducted a thematic analysis. Our analysis suggests that there were significant differences in legal post-disaster decisions in the cases of Mariana and Brumadinho. In Mariana, there was privatization of post-disaster management, with the creation of the Renova Foundation, a mediated indemnity program, lack of access to information for those affected, and uncertainties in health and resettlement issues. In Brumadinho, there was faster implementation of the recovery and compensation measures, faster recognition of affected parties, and stronger participation of the population since the first hearings. Even though there were particularities in post-disaster management, the ultimate goal of the corporations responsible for the disasters was to protect their profits.

Lonchocarpus cultratus, a Brazilian savanna tree, endures high soil Pb levels

Industrial revolution markedly increased the environmental contamination by different pollutants, which include the metal lead (Pb). The phytoremediation potential of native species from tropical regions is little known, especially for woody plants. The present study aimed to evaluate the performance of Lonchocarpus cultratus (Fabaceae), a tree species from the Brazilian savanna, grown in soil that was artificially contaminated with increasing Pb concentrations (control and 4 Pb treatments, 56, 120, 180, and 292 mg kg^-1) for 6 months. The biomass of L. cultratus was not depressed by exposure to Pb, despite the high accumulation of this metal (up to 7421.23 μg plant^-1), indicating a high plant tolerance to this trace metal. Lead was mainly accumulated in roots (from 67 to 99%), suggesting that the low root-to-shoot Pb translocation is a plant strategy to avoid Pb-induced damages in photosynthetic tissues. Accordingly, the content of chlorophylls a and b was maintained at similar levels between Pb-treated and control plants. Moreover, increments in leaf area were noticed in Pb-treated plants in comparison to the control plants (on average, 24.7%). In addition, root length was boosted in plants under Pb exposure (22.6-66.7%). In conclusion, L. cultratus is able to endure the exposure to high Pb concentrations in soil, being a potential plant species to be used for Pb phytostabilization in metal-contaminated soils in tropical regions.

Physicochemical, microbiological quality, and risk assessment of water consumed by a quilombola community in midwestern Brazil

The quality of the water consumed by a given community is related to its quality of life. In this sense, this study aimed to evaluate, from the perspective of health risk, the physical, chemical, and microbiological quality of drinking water, in a quilombola community, and the qualitative aspects intrinsic to its use and storage. For this, water samples, collected at the exits of the collective water supply system and from eight cisterns that store rainwater, used for human consumption, were analyzed. The samples were subjected to physical, chemical, and microbiological analysis, including adenovirus (HAdV) and enterovirus (EV). The probability of an individual acquiring infection through water consumption was determined by quantitative microbiological risk analysis using HAdV and Escherichia coli (EC) as reference pathogens. The results showed that the water in the deep tubular well had 270.8 mg/L of total hardness, leading to the rejection of its consumption by ingestion. Alternativity, the people in the community consume rainwater stored in cisterns. For this type of water, the presence of heterotrophic bacteria was found in 75%, total coliform was present in 100%, and Enterococci were detected in 25%. Furthermore, EC was present in 25%, EV in 50%, and HAdV in 100% of the samples. The probability of annual infection with HAdV and EC was, in the worst situation, 100% and 1.3%, respectively. Regarding the qualitative and quantitative aspects, there was a significant positive correlation between the absence of EC and the withdrawal of water from the cistern using a pump and the opposite when the withdrawal was carried out using a bucket or hose. Based on the results found, it is important to carry out actions aimed at improving water quality and, consequently, the quality of life of people living in the study community.

Effect of mixed bacteria on cemented tailings backfill: Economic potential to reduce binder consumption

Tailings used as backfilling material in the presence of mixed bacteria are discussed, and the relationship between mixed bacteria and compressive strength, size variation, water-holding capacity is analyzed in this study. The results illustrate a strong improving response of mixed bacteria with enhanced compressive strength, small size variation and low water-holding capacity of cemented tailings backfill (CTB) specimens. The binder dosage and mixed bacteria proportion have great influence on CTB specimens, which indicate that with the increase of mixed bacteria proportion and binder dosage, compressive strength increased obviously. The maximum compressive strength (4.01 MPa) is obtained in the presence of 100.00% mixed bacteria in contrast to only 2.79 MPa in its absence. Samples added high mixed bacteria proportion yield low water-holding capacity and small size variation. 16S rDNA analysis illustrates that bacteria community is influenced significantly during experiment. Further, possible reaction mechanism is proposed suggesting the possible role of mixed bacteria as promoter to form precipitation (KFe₃(SO₄)₂(OH)₆, (NH₄)Fe₃(SO₄)₂(OH)₆ and (KH₃O)₄Fe₃(SO₄)₂(OH)₆), which reduces tiny cracks in CTB specimens. The technique of using mixed bacteria to reduce binder consumption in this study shows economic benefits to some extent.

Time-sequence development of metal(loid)s following the 2015 dam failure in the Doce river estuary, Brazil

In the context of the Doce river (Southeast Brazil) Fundão dam disaster in 2015, we monitored the changes in concentrations of metal(loid)s in water and sediment and their particulate and dissolved partitioning over time. Samples were collected before, during, and after the mine tailings arrival to the Doce river estuary (pre-impact: 12, 10, 3 and 1 day; acute stage: tailing day - TD and 1 day after - DA; chronic stage: 3 months and 1 year post-disaster). Our results show that metal(loid) concentrations significantly increased with time after the disaster and changed their chemical partitioning in the water. 35.2 mg Fe L^-1 and 14.4 mg Al L^-1 were observed in the total (unfiltered) water during the acute stage, while aqueous Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn concentrations all exceeded both Brazilian and international safe levels for water quality. The Al, Fe and Pb partitioning coefficient log (K_d) decrease in the acute stage could be related to the high colloid content in the tailings. We continued to observe high concentrations for Al, Ba, Cd, Cr, Cu, Fe, V and Zn mainly in the particulate fraction during the chronic stage. Furthermore, the Doce river estuary had been previously contaminated by As, Ba, Cr, Cu, Mn, Ni and Pb, with a further increase in sediment through the tailing release (e.g. 9-fold increase for Cr, from 3.61 ± 2.19 μg g^-1 in the pre-impact to 32.16 ± 20.94 μg·g^-1 in the chronic stage). Doce river sediments and original tailing samples were similar in metal(loid) composition for Al, As, Cd, Cr, Cu, Fe, V and Zn. As a result, these elements could be used as geochemical markers of the Fundão tailings and considering other key parameters to define a baseline for monitoring the impacts of this environmental disaster.

N-compounds speciation analysis in environmental samples using ultrasound-assisted solid-liquid extraction and non-chromatographic techniques

A fast, efficient, and non-chromatographic method was presented in this study for nitrite, nitrate, and p-nitrophenol (N-compounds) extraction and speciation analysis of environmental samples. By applying ultrasound-assisted solid-liquid extraction (USLE), analytes were efficiently extracted from water, soil, or sediment collected in areas of environmental disaster. These analytes were selectively converted to NO_(g) through UV photolysis (NO₃^-), H₂O₂/UV photocatalysis (PNP), and direct conversion (NO₂^-). Following conversion, NO_(g) was separated from the liquid phase and determined by high-resolution continuum source molecular absorption spectrometry (HR-CS MAS). The LODs obtained were 0.097 ± 0.004 mg L^-1 for nitrite, 0.119 ± 0.004 mg L^-1 for nitrate, and 0.090 ± 0.006 mg L^-1 for p-nitrophenol. On applying this speciation method to environmental samples, concentrations were found to be up to 0.99 ± 0.03 mg L^-1 (NO₂^-), 49.80 ± 2.5 mg L^-1 (NO₃^-), and 0.10 ± 0.02 mg L^-1 (PNP). Finally, addition/recovery study of real water, soil, and sediment samples showed 101 ± 2% recovery for NO₂^-, 100 ± 1% for NO₃^-, and 96 ± 5% for PNP.

Social injustice in environmental health: A call for fortitude

The objective of this short paper is to call upon the scientific community to channel its attention to the duty and heedfulness of social justice issues. While recognized for decades the impact of social injustice on public health and its disproportionate effects on poorer communities, little has been done to systematically address it. Here, we provide several examples pertinent to the health outcomes associated with social injustice and call upon the scientific community to attend to the issue and antagonize those who attempt to subvert science and its role in ensuring social justice in health.

First year after the Brumadinho tailings' dam collapse: Spatial and seasonal variation of trace elements in sediments, fishes and macrophytes from the Paraopeba River, Brazil

On January 2019, the B1 iron ore tailings' dam collapsed in Brumadinho, Brazil, being one of the worst mining-related disasters, with 270 human deaths (11 of them still missing) and 12.10⁶ m³ of tailings released to the environment. The tailings devastated the Córrego do Feijão brook and reached the adjacent Paraopeba River, the region's main watercourse and a major tributary of the São Francisco basin. Although physicochemical parameters of the river were strongly impacted, and acute toxicological effects have been reported from exposure experiments, contamination of aquatic biota had not yet been assessed. Therefore, the aim of this study was to evaluate contamination by trace elements (As, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in sediment, fish and macrophytes along the Paraopeba River, upstream and downstream from the dam failure site, during the dry and wet season. With the exception of Cd and Hg, all elements in sediment samples had lower median concentrations downstream. An inverse pattern was observed for the aquatic biota, with significant higher concentrations of Fe, Mn, Ni and Zn in fishes, and increased concentrations of most elements in macrophytes, indicating an increase in element bioavailability. A significant seasonal variation was observed with increased concentrations of As (dry season) and Pb (wet season) in fish samples, with the same trend occurring in macrophytes. Concentrations of potentially toxic elements in fish samples in wet weight (Cr: 1.80 ± 1.31 mg kg^-1, Hg: 0.21 ± 0.11 mg kg^-1 and Pb: 0.79 ± 0.80 mg kg^-1) were lower than those reported before the disaster. Furthermore, As and Pb concentrations exceeded the safety threshold for fish consumption in 3% and 41% of samples, respectively, representing a matter of concern for public health.

Trace metals in Rio Doce sediments before and after the collapse of the Fundão iron ore tailing dam, Southeastern Brazil

The collapse of the Fundão Dam, in Southeastern Brazil, caused about 50 million m³ of iron ore tailings to sluice down the mountain to Rio Doce, in what is considered the greatest environmental disaster in Brazilian history. The fluvial system received an intense and sudden mudflow that was transported for more than 650 km, before reaching the Atlantic Ocean. Because the area was already impacted by the mineral activities in the region, it becomes essential to evaluate the environmental conditions before the disaster to correctly assess the disaster real damage. This study compares the concentration of trace metals in the sediments of the Rio Doce alluvial plain, before and after the dam collapse, as well as the newly deposited iron ore tailings that became part of the sedimentary framework. The data indicate that the fine particles deposited have since been incorporated into the sandy river sediments. The cadmium and arsenic contents in the sediments increased to levels above the National Environment Council thresholds. The comparison between the levels of trace metals in the situations before and after disaster shows that the mining mud is the source of cadmium while the arsenic was present before the environmental disaster, and its concentration increased due to sediment remobilization. The iron ore tailings deposited on the alluvial sediments also affected the physical parameters since the formed ferruginous crusts waterproofed the ground surface and may, gradually, release toxic metals when exposed to weathering and river reworking.

Negative impacts of mining on Neotropical freshwater fishes

Abstract Mining activities have significantly affected the Neotropical freshwater ichthyofauna, the most diverse in the world. However, no study has systematized knowledge on the subject. In this review, we assembled information on the main impacts of mining of crude oil, gold, iron, copper, and bauxite on aquatic ecosystems, emphasizing Neotropical freshwater fishes. The information obtained shows that mining activities generate several different disturbances, mainly via input of crude oil, metals and other pollutants, erosion and siltation, deforestation, and road construction. Mining has resulted in direct and indirect losses of fish diversity in several Neotropical waterbodies. The negative impacts on the ichthyofauna may change the structure of communities, compromise entire food chains, and erode ecosystem services provided by freshwater fishes. Particularly noteworthy is that mining activities (legal and illegal) are widespread in the Neotropics, and often located within or near protected areas. Actions to prevent and mitigate impacts, such as inspection, monitoring, management, and restoration plans, have been cursory or absent. In addition, there is strong political pressure to expand mining; if – or when – this happens, it will increase the potential of the activity to further diminish the diversity of Neotropical freshwater fishes.

Morphostructural data and phylogenetic relationships of a new cnidarian myxosporean infecting spleen of an economic and ecological important bryconid fish from Brazil

A new cnidarian myxosporean infecting the spleen of an economic and ecological important bryconid fish (Salminus franciscanus) is described based on integrative taxonomic approach including morphological, ultrastructural, biological traits, geography, molecular data and phylogenetic analysis. In a total of thirty specimens examined, nineteen (63.3%) were infected by an undescribed parasite species belonging to the genus Myxobolus. Plasmodial development was asynchronous, with young development in the periphery and mature myxospores in the central area and without projections and microvilli in the plasmodial wall. Mature myxospores were ovoid in shape and measured 7.9 ± 0.2 μm (7.6-8.1 μm) in length and 5.4 ± 0.1 μm (5.0-5.6 μm) in width. The two polar capsules were equal in size, occupying a little more than half of the myxospore body, measuring 4.0 ± 0.2 μm (3.9-4.1 μm) in length and 1.7 ± 0.1 μm (1.5-1.8 μm) in width. The polar tubules coiled in six turns, perpendicular to the long axis of polar capsule. Phylogenetic analysis placed the new species within a clade containing nine myxobolid species from South American characiforms fish and appears as a close species of Myxobolus pantanalis. Nevertheless, the sequences of the new species and M. pantanalis have a large genetic divergence of 13.5% in their SSU rDNA. In light of the differences observed from the integrative taxonomy, we confidently considered that this isolate is a new species of cnidarian myxosporean, M. douradae n. sp., increasing the knowledge of diversity of this enigmatic group of cnidarians.

Mining Waste Challenges: Environmental Risks of Gigatons of Mud, Dust and Sediment in Megadiverse Regions in Brazil

The management of long-lived mining wastes is a complex environmental challenge, but the subject is little discussed among the public, scientific community, and policymakers. The negative environmental impacts caused by mining wastes are severe and cause damage to human health and the loss and degradation of natural ecosystems. With the objective of stimulating discussion to advance the development of measures to contain threats to biodiversity and to mitigate negative impacts, we present an overview of total volumes of mining waste disposal in tailings dams and dump piles, discriminating them by ore type and biome. We highlight the major environmental risks and challenges associated with tropical forests, savannas, and freshwater ecosystems and possible limitations and advances in public policies and governance. The scale of this challenge is global, as some data show, for example, Brazil generated 3.6 billion tons of solid mining waste in dump piles in the period between 2008 and 2019. The volume is equivalent to 62% of the global mass of nonfuel minerals removed from the planet’s crust in 2006. Numerous socio-environmental disasters are caused by catastrophic mining dam failures, and over the last 34 years, an average of one failure has occurred every three years in Brazil.

Tolerance of Landoltia punctata to arsenate: an evaluation of the potential use in phytoremediation programs

Plants used in phytoremediation should accumulate and tolerate a specific pollutant. Here, we aimed at evaluating a possible arsenic (As) accumulation and mechanisms of tolerance against As-induced damage in Landoltia punctata to explore this species for phytoremediation. Plants were subjected to increasing As levels. As absorption was higher with increasing As levels. The activity of superoxide dismutase and glutathione reductase as well as anthocyanin levels increased with As levels. Catalase and peroxidase activities increased in plants subjected to As levels up to 1.0 mg L^-1 and decreased at higher levels. Due to the antioxidant system, higher levels of reactive oxygen species were restrained in plants under low levels of As. However, the levels of superoxide anion, hydrogen peroxide, and lipid peroxidation increased in response to the impaired antioxidant system induced by the highest As levels. Biomass decreased in plants exposed to As and scanning electron microscopy revealed root structural damage in the root cap of plants under 3.0 mg L^-1As. This work highlights that L. punctata can be considered a hyperaccumulator species and has potential for As phytoremediation when levels are lower than 1.0 mg L^-1-a concentration 100-fold higher than that recommended for drinking water. Novelty Statement: Landoltia punctata can be considered a hyperaccumulator species and has the potential for arsenic phytoremediation when levels are lower than 1.0 mg L^-1.