Doce River Research Articles

Ecotoxicological impacts of the Fundão dam failure in freshwater fish community: Metal bioaccumulation, biochemical, genetic and histopathological effects

This study investigates the ecotoxicological impacts of the Fundão dam rupture, one of the major environmental disaster that occurred in Brazil and in the world mining industry history, through multi-biomarkers responses and metals bioaccumulation in the fish community of different trophic levels. Specimens of the fishes (omnivorous/herbivorous and carnivorous) were collected along the Doce River channel and its affluent Guandú River, and in different lakes and coastal lagoons adjacent to the river channel, in the Espirito Santo State, Southeast of Brazil. Four sampling collections were carried out over two years (2018 to 2020, during dry and rainy seasons). For both trophic groups the biomarkers responses indicated physiological alterations related to metals exposure and showed strong seasonal variations. The principal component analysis and integrated biomarker response index showed that DNA damage and lipid peroxidation were more associated with dry season 2 (Sep/Oct 2019) and the oxidative damage in proteins, metallothioneins concentration and the activity of superoxide dismutase in the gills showed a greater association with rainy season 2 (Jan/Feb 2020). On the other hand, the enzymes of energy metabolism, catalase and histological damage in the liver and the gills, were more associated with the dry and rainy campaigns of the first year of monitoring. The multivariate approach also suggested a temporal intensification in the bioaccumulation of metals and biological effects in the lacustrine environments. Thus, these results demonstrate that the release of mineral residues from the rupture of the Fundão mine dam affects the health status of the fish from the Doce River basin, provoking metals bioaccumulation, hepatic and branchial damage in the fish besides inducing of enzyme activity related to metal contamination, even four years after the rupture.

A simpler statistical approach to estimate the allowable effluent discharge into a low monitored river network

The goal of the study was to illustrate how the variation in streamflow patterns affects the magnitude of pollutants that can be loaded into the hydrography in a more straightforward manner. For that, two basins in the Doce River basin (Brazil) were evaluated in order to estimate the variation in the allowed wastewater in streamflow units (m3s−1) into the hydrography without impairing the rivers' water quality. The main water quality parameters of the basin were considered for the analysis: E. coli, total phosphorus (P), nitrate‑nitrogen (N-NO3−), and biochemical oxygen demand (BOD). Because the already existing E. coli in the system is too high, the allowable streamflow, considering this pollutant, was null. For N-NO3−, the model was not valid because the concentration of it the wastewater is smaller than the allowed in the legislation. For last, considering P and BOD, it was observed that, for most gauges, it was possible to load more wastewater in the hydrography during wet months, especially when the effluent goes through some treatment. For example, considering P, a significant difference between the allowable pollutants in the wet season in comparison to the dry season, indicating that for one gauge, more wastewater is allowed in the dryer season. For BOD, contrarily, the allowable wastewater in the hydrography increased by about 50% in both seasons, without much variation. With that, we conclude that the dilution capacity in the waters is variable, so should be the allowed amount of pollutants into the river network throughout the year.

Impacts of tailings of Fundão dam (Brazil) rupture on marine fish: Metals bioaccumulation and physiological responses

This study evaluated the impacts of the mining tailings after the rupture of the Fundão dam on fish communities on the Atlantic Ocean southeast coast. Four sample collections were carried out over two years (2018–2020), in seasonal periods. Omnivorous/herbivorous and carnivorous fish were collected for analysis of metal bioaccumulation, multibiomarkers of environmental contamination and histopathology. Metal bioaccumulation was stronger correlated in carnivorous fish in the dry-2018 collection, besides higher activity of antioxidant enzymes, energy metabolism and higher morphological damage; however, there was less oxidative damage and less metallothioneins induction, and these variables were strongly associated with the wet-2020 collection. In a temporal view, it was possible to observe a reduction in metal levels in fish, except in the mouth of the Doce River. These events can be explained by seasonal natural events, which tend the resuspension and boost metal levels, mainly in the mouth region during the rainy season.

Deep Genomic Divergence and Phenotypic Admixture of the Treefrog Dendropsophus elegans (Hylidae: Amphibia) Coincide With Riverine Boundaries at the Brazilian Atlantic Forest

The Atlantic Forest (AF) domain is one of the Earth’s biodiversity hotspots, known for its high levels of species diversity and endemism. Factors related to palaeoenvironmental dynamics, such as the establishment of vegetational refugia and river basins, have different impacts on biological communities and biodiversity patterns in this domain. Here, we sample genome-wide RADseq data from a widespread treefrog (Dendropsophus elegans), inhabiting natural and human-impacted ecosystems at the Brazilian AF to test the impact of riverine boundaries and climatic refugia on population structure and diversification. We estimate divergence times and migration rate across identified genetic breaks related to the rivers Doce, Paraíba do Sul, Ribeira de Iguape, and Paraguaçu, known to represent barriers to gene flow for other AF endemic species, and test the role of climatic refugia. Finally, we investigate the impact of spatio-temporal population history on morphological variation in this species. We recovered a phylogeographic history supporting three distinct clades separated into two geographically structured populations, corresponding to the north and south of AF. In addition, we identified an admixture zone between north and south populations in the latitude close to the Doce River. Our findings support a pattern of isolation-by-distance and the existence of a secondary contact zone between populations, which might have been promoted by gene flow during population expansion. Further, we found support for models considering migration parameters for all the tested rivers with different population divergence times. Based on the species history and the AF palaeoenvironmental dynamics, we corroborate the role of forest refugia impacting population structure for this species through recent range expansion after the Last Glacial Maximum (LGM). The Doce and Paraíba do Sul Rivers coincide with the main genetic breaks, suggesting they might also have played a role in the diversification processes. Finally, despite finding subtle correlations for phenotypic data among different populations, variation is not strongly detectable and does not seem associated with speciation-level processes that could warrant taxonomic changes. Such results can be explained by phenotypic plasticity of the evaluated traits and by recent divergence times, where there has been insufficient time and weak selective pressures to accumulate enough phenotypic differences.

Problematizing the wickedness of the Fundão dam rupture: Are cross-sector partnerships enough to bring about the Doce river basin recovery process?

This paper aims to draw attention to the intricacies of hybrid network governance in a challenging institutional landscape. The empirical focus is a case study of the recovery process from the Fundão dam rupture, Brazil’s most significant environmental disaster, and the largest in the world involving tailings dams. To drill into the barriers to cross-sector partnerships, we adopted a multi-methods approach, including interviews, grey materials and documents, participant observation and social network analysis. We identified interrelated barriers and grouped them into institutional, power and knowledge barriers, which act through a positive feedback loop leading to a structural arrangement that is inadequate for collaboration in disaster management. As a result, the Doce river basin’s recovery process has taken the form of a wicked industrial disaster, enabling a “chain reaction” of increasing wickedness. We thereby advance cross-sector partnership research by drawing attention to the underlying causes of failure and offer guidance to public and private managers on possible strategies to address the barriers to cross-sector partnerships.

Environmental disaster in mining areas: routes of exposure to metals in the Doce River basin

Environmental disaster in mining areas: routes of exposure to metals in the Doce River basin

A Feminist Analysis of the Legal Mechanisms of Protection and Repair in the Context of the Brazilian Extractive Industry: The Doce River Case

This piece uses the Doce River case (2015) to illustrate the gendered impacts of the failure of corporate human rights due diligence. We also ask the question: would the Gender Dimensions of the Guiding Principles on Business and Human Rights1 (Gender Guidance) have made a difference to the way women were treated in preventive measures taken and in the application of redress mechanisms? Taking this specific case, we seek to illustrate the importance of integrating gender into international business and human rights (BHR) frameworks if women’s rights are to be protected and respected in the context of business activities.

Variability in nearshore fish biodiversity indicators after a mining disaster in eastern Brazil

The rupture of the Fundão mining dam (Doce river basin, Brazil) caused a wide range of negative impacts. Yet, assemblage-level implications to estuarine and coastal fishes remain unclear, partly due to the lack of pre-disaster information. Based on monthly otter trawl surveys, we analyzed spatial and seasonal variability in univariate (total biomass, biomass of species vulnerable to exploitation, rarefied richness and evenness) and multivariate (species composition and trophic composition) indicators of fish biodiversity in the Doce river delta, eastern Brazil. We determined the independent and interactive effects of environmental, seasonal and spatial variables on species composition to test whether environmental alterations provoked by mine tailings could affect assemblage's organization. Most indicators present idiosyncratic spatiotemporal patterns, suggesting they have complementary roles in revealing changes in fish biodiversity. Environmental variables, including those affected by the Fundão dam collapse such as turbidity, dissolved oxygen and pH, were much more important than seasonal and spatial predictors in explaining the variation in fish species composition. These findings highlight the potential from mine tailings to disrupt local ichthyofauna and indicate a preponderant role of environmental conditions in assemblage structuring. Given the lack of data prior to rupture, our results may be used as a baseline against which to assess temporal trends in fish biodiversity relative to changes detected in less disturbed estuarine and coastal assemblages.

Phylogeography of the Neotropical sciurid Guerlinguetus brasiliensis (Rodentia: Sciuridae)

Abstract The Brazilian squirrel Guerlinguetus brasiliensis is the only sciurid species occurring in the Atlantic Forest. We investigated the geographical distribution of the genetic diversity of this sciurid species across the Central Corridor of the Atlantic Forest, using two mitochondrial markers and one nuclear marker. We also inferred the demographic history and estimated the present and past habitat suitability for the species. We found strong mitochondrial DNA structure, possibly with both the Doce River and the valley of Paraíba do Sul River restricting gene flow between populations. The demography and ecological niche modelling highlighted a shared evolutionary history amongst several forest-dependent species in the Atlantic Forest. A pattern of isolation by distance was also found, revealing the low mobility and/or dispersal capacity of the species. Further data are required to disentangle exactly how past and/or recent habitat changes have affected population-level genetic diversity of G. brasiliensis.

New insights into metal(loid) dynamics in the Doce River estuary (Brazil) after a massive iron ore-processing tailing dam collapse.

The present study investigated metal and metalloid dynamics in theestuarine water of the Doce River (Brazil) after the collapse of an iron ore-processing tailing dam in 2015. Spectroscopic and isotopic techniques were applied to bring new insights into the effects of the dam failure on the dynamics and hazardousness of particulate and dissolved metal(loid) concentrations along the fluvial-estuarine continuum. Spectroscopic analysis showed that the suspended particulate matter (SPM) of the Doce River estuary consisted of a combination of soil-delivered particles and fine tailing mud particles with small amounts of coarse tailing mud Fe oxides (~150-μm width). Enrichment and contamination factors showed that the dam failure increased particulate Fe, Pb, Cd, and As, and dissolved Pb concentrations. Total concentrations of As (15 μg/L), Pb (30 μg/L), Cd (8 μg/L), and Cr (105 μg/L) increased up to values higher than quality and regulatory guidelines. Human health risk assessment showed that local communities are exposed to a potentially chronic Cr noncarcinogenic effects, although Cr high concentrations were not linked with the dam failure by this study. The particulate Pb isotope signatures reported herein (206/207Pb ratios of 1.214 ± 0.006 and 208/206Pb ratios of 2.025 ± 0.011) can be applied to constrain metal(loid) sources in the Doce River sediment plume and continental shelf. The river-ocean mixing zone caused abrupt changes metal(loid) partitioning (Zn, Pb, Cr, Cu, Cd, and As), controlling their fate in the estuary and the Brazilian southeast coastal.

Health condition of Chelonia mydas from a foraging area affected by the tailings of a collapsed dam in southeast Brazil

In 2015, the failure of the Fundão dam caused the release of 43 million m3 of tailings into the Doce River Basin, in southeast Brazil. It was considered the largest environmental disaster of the world mining industry. The tailings, composed mostly of heavy metals, caused massive destruction of the Doce River ecosystem endangering the organisms that live in the coastal zone where the mud reached the ocean. Among the exposed species are the sea turtles that use the region for food. The aim of this study was to evaluate the effect of contaminants on the health status of juvenile green sea turtles that feed in a coastal area exposed to ore mud (Santa Cruz) and to compare them with animals from an area not directly affected (Coroa Vermelha). A physical examination was performed to determine the health status. Blood samples were analyzed for hematological and biochemical parameters, and metal concentrations (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn). Santa Cruz sea turtles had more ectoparasites and a higher incidence of fibropapillomatosis. Statistically significant differences between sites were found for levels of calcium, phosphorus, glucose, protein, albumin, globulin, cholesterol, triglycerides, urea, CPK, ALT, and AST. The count of leukocytes, thrombocytes, and heterophils, as well as the concentrations of As and Cu were higher in Santa Cruz turtles. Together the results show a worse nutritional status and a greater degree of liver and kidney damage in animals affected by the tailings. The health status may indicate a physiological deficit that can affect their immune system and behavior, which is supported by the higher fibropapillomatosis tumor score and ectoparasite load in these animals. These results support the need for long-term monitoring of the exposed area to quantify the direct and indirect influence of the heavy metals levels on sea turtles and how this reflects the environmental health.

Emerging Contaminants in Streams of Doce River Watershed, Minas Gerais, Brazil

This study investigated the occurrence and risk assessment of ten pharmaceutical products and two herbicides in the water of rivers from the Doce river watershed (Brazil). Of the 12 chemicals studied, ten (acyclovir, amoxicillin, azithromycin, ciprofloxacin, enrofloxacin, fluoxetine, erythromycin, sulfadiazine, sulfamethoxazole, glyphosate and aminomethylphosphonic acid) had a 100% detection rate. In general, total concentrations of all target drugs ranged from 4.6 to 14.5 μg L−1, with fluoroquinolones and sulfonamides being the most representative classes of pharmaceutical products. Herbicides were found at concentrations at least ten times higher than those of the individual pharmaceutical products and represented the major class of contaminants in the samples. Most of the contaminants studied were above concentrations that pose an ecotoxicological risk to aquatic biota. Urban wastewater must be the main source of contaminants in waterbodies. Our results show that, in addition to the study of metal in water (currently being conducted after the Fundão dam breach), there is an urgent need to monitor emerging contaminant in waters from Doce river watershed rivers, as some chemicals pose environmental risks to aquatic life and humans due to the use of surface water for drinking and domestic purposes by the local population. Special attention should be given to glyphosate, aminomethylphosaphonic acid, and to ciprofloxacin and enrofloxacin (whose concentrations are above predicted levels that induce resistance selection).

Spreading and accumulation of river-borne sediments in the coastal ocean after the environmental disaster at the Doce River in Brazil

This study is focused on the fate of a large volume of mine slurry discharged from the Doce River (DR) to the coastal ocean after the worst environmental disaster in Brazilian which occurred in November 2015. We used Eulerian (ROMS) and Lagrangian (STRiPE) numerical models, as well as satellite remote sensing data, to study the spreading and seafloor accumulation of fine river-borne sediments during the initial six months following the disaster. We show that the regions of intense sediment accumulation were determined by spreading patterns of the surface-advected DR plume. The river discharge rate governed the plume surface area, while its position depended on local wind forcing conditions. The spreading of sediments carried by the DR plume was dominated by southward transport caused by prevailing upwelling-favorable northeasterly winds during the study period. Under high discharge conditions, river-borne sediments were transported over 100 km southward from the DR mouth and reached the outer shelf. In contrast, sediments were arrested near the mouth during drought periods and remained on the inner shelf. As a result, fine river-borne sediments accumulated on the seafloor, mainly in the large shallow shelf area southward from the DR mouth. Conversely, only a small fraction of residue was deposited northward. Thus, the Environmental Protection Area (EPA) of Costa das Algas, located 40 km southward from the DR, potentially exhibited more susceptibility to sediment arrival. On the other hand, their influence on Abrolhos Marine National Park, located 200 km northeastward from the DR mouth, was presumably minimal.

Fish biodiversity of a tropical estuary under severe anthropic pressure (Doce River, Brazil)

Abstract The Doce River has undergone severe changes over the last centuries (e.g., flow regulation, pollution, habitat and species loss). Here, we present the first comprehensive fish biodiversity assessment of the Doce River estuary and a summary of the main impacts and their drivers for the whole river since the early 18th century. Carangiformes, Siluriformes and Eupercaria incertae sedis were the most representative orders for the 115 species recorded. Most species are native (87.8%), euryhaline/peripheral (80%) and zoobenthivorous (33.9%). Threatened (Paragenidens grandoculis, Genidens barbus, and Lutjanus cyanopterus) and near threatened (Cynoscion acoupa, Dormitator maculatus, Lutjanus jocu, Lutjanus synagris, and Mugil liza) species are peripheral. Thirteen species are exotic at the country (Butis koilomatodon, Coptodon rendalli, and Oreochromis niloticus) or the basin level (e.g., Pygocentrus nattereri and Salminus brasiliensis). The catfish Cathorops cf. arenatus is reported for the first time on the eastern coast of Brazil and Paragenidens grandoculis, considered extinct in the Doce River, was discovered in the estuary.

Changes in dietary and water use habits after the Doce River contamination with mining tailings

The Fundão dam burst polluted watercourses with mining tailings and harmed cities bathed by Doce River, that might have changed eating habits. This study evaluated changes in dietary habits and water use in Araújos Island, Governador Valadares, Minas Gerais, southeastern Brazil, after contamination of the Doce River with mining tailings. Data were collected in residences through interviews using semi-structured questionnaires. Seventeen months after disaster, 73% of habitants changed water use habits, mainly for cooking (53%). Public supply water (PSW) was partially replaced for other sources, mainly mineral water. Additionally, 54% changed their dietary habits by reduction or interruption of the consumption of freshwater fish (50%), fruit (28%), vegetables (27%) and food made outside the home (40%). Most of them (96%) perceived an addition risk to food production after disaster. Financial (69%) and psychological (55%) damages as well as health risk (39%) were the negative effects most frequently mentioned. Only 13% positively evaluated the quality of PSW while 77% believe PWS may cause some type of damage in foods. Part (59%) did not believe in information regarding potability of PSW. These changes would be associated with healthier lifestyle habits, health risk perception about water quality and safety and lack of confidence about water potability.

DEVELOPMENT OF A WATER QUALITY INDEX WITH A REDUCED NUMBER OF PARAMETERS

The development of water quality indices (WQIs), duly modified and using a small number of parameters, may be of great economic use. The purpose of this work was to develop a WQI with a reduced number of parameters (WQIred), in relation to what is used in the Brazilian state of Minas Gerais (WQIIGAM), in the basin of the Doce River. Four different scenarios were analysed, with the absence of the following parameters for the calculation of the WQIred: BOD, E. coli and phosphate; BOD and E. coli; BOD, E. coli and total solids (TS); BOD, E. coli, phosphate and TS. The redistribution of the weight attributed to the eliminated parameters was done according to the following methods: (i) in weighted form, through optimisation of the correlation between the WQIred and the WQIIGAM; (ii) based on the cluster analysis. The best scenario found was that of the WQIred considering only DO, pH, temperature variation, nitrates and turbidity, with the weights being redistributed based on cluster analysis. This scenario maintained satisfactory performance, with a minimum difference being observed between WQIIGAM and WQIred, in terms of management purpose. The WQIred as proposed makes it possible to establish a monitoring control system operating in real time in the Doce river basin, as all the parameters considered can be obtained with the use of multiparameter probes.

Can the introduction of non-native fish induce variation in life-history traits of a native species in a neotropical lake?

Top predator fish, such as peacock bass (Cichla kelberi) and red-bellied piranha (Pygocentrus nattereri), were introduced in the lacustrine system of the Rio Doce basin and these introductions are associated with loss of aquatic biodiversity. The present work aims to investigate the life-history traits of a native species, thraira (Hoplias malabaricus), in the context of the pressures caused by the introduction of top predator fishes. Two lakes were selected in a conservation unit Doce River State Park (PERD), namely, Lake Carioca, where P. nattereri and C. kelberi were introduced, and Lake Gambazinho, where H. malabaricus occurs in the absence of introduced fish. In total, 146 specimens of H. malabaricus were caught, including 95 in Lake Gambazinho and 51 in Lake Carioca. Significant differences were found in the length–weight relationship (LWR) in the diet, the reproductive period, the vitellogenic follicle size, and the gonadosomatic index (GSI). In the lake with introduced species, thrairas showed allometric growth, a less diversified diet, longer duration of the reproductive period, and high GSI values compared with the control lake. The results indicated that the life-history traits of thrairas can be influenced by the environmental modification caused by the introduction of non-native peacock bass and red-bellied piranha.

(Ficoflórula perifítica do Baixo Rio Doce, Estado do Espírito Santo, Brasil, após passagem de rejeitos de minério, 1: Cosmarium Corda de parede lisa (Zygnematophyceae, Desmidiaceae.

ABSTRACT Study aimed at identifying and recording smooth or finely punctate cell walled Cosmarium Corda species of the low Doce river region, Espírito Santo State, Brazil. Periphytic material was collected monthly during the period October 2018 to February 2020, except for October 2019. We identified 22 taxa and analyzed the environmental conditions (trophic state, pH and total iron) in which each taxon occurred. Our study recorded 21 new records of smooth cell walled Cosmarium for Espírito Santo State and one (Cosmarium trilobulatum var. tumidum Willi Krieger & Gerloff) for Brazil.

Chemical composition, vitamins, and minerals of family farming biribiri (Averrhoa bilimbi L.) in the Middle Doce River region, Minas Gerais, BrazilTítulo 12

ABSTRACT: This study evaluated physical characteristics, chemical composition, content of vitamin C, vitamin E, carotenoids, and minerals in biribiri fruits (Averrhoa bilimbi) from the Middle Doce River region (Minas Gerais, Brazil). Titratable acidity was determined by volumetric neutralization, pH by direct potentiometry, soluble solids by refractometry, humidity by gravimetry, ash by calcination in muffle, proteins by the micro-Kjeldahl method, dietary fiber by non-enzymatic gravimetric method and lipids using a Soxhlet extractor. Carotenoids and vitamin C were analyzed by high-performance liquid chromatography (HPLC) and vitamin E by HPLC with fluorescence detector. Fourteen minerals were analyzed by inductively coupled plasma atomic emission spectrometry. Biribiri showed high yield of edible portion (100%), low lipid, protein and carbohydrate content, and; consequently, low total energy value (25.36 kcal 100 g-1). The fruit also showed low dietary fiber content (0.62 g 100 g-1), total vitamin E (17.62 µg 100 g-1), total carotenoids (0.32 g 100 g-1), and high vitamin C, zinc, copper, iron content, manganese, molybdenum and chrome content. Regarding the heavy metals, the fruit showed no cadmium, and traces of aluminum and nickel. In conclusion, biribiri presented low energy value and expressive contents of dietary fibers, vitamin C, iron, manganese, molybdenum, chromium, zinc, and copper.

Impact of climate change on the flow of the Doce River basin

ABSTRACT This study verified the impacts of climate change on river flow in the Doce River basin, using the MGB and RCM Eta projections. Despite the differences between the trends, the basin will certainly be affected by the reduction of precipitation and the increase in temperature between 2025 and 2099. Results show considerable reductions in the trends of the average flow of the basin. In 2025 - 2049, these reduction trends are greater than 64% in 50% of river reaches, according to Eta-HadGEM2-ES RCP 8.5. In 2050 - 2074, the flows simulated with Eta-CanESM2 and Eta-HadGEM2-ES RCP 8.5 achieve reductions greater than 84% and 77%, respectively, in 50% of the simulated reaches. In 2075 - 2099 the reduction trends of Eta-CanESM2 and Eta-HadGEM2-ES RCP 8.5 are greater than 91% and 79%, respectively, in 50% of the drainage reaches.