Sul River Research Articles

A comprehensive study on bisphenol A and estrogenic activity in the Paraíba do Sul River, São Paulo, Brazil

A comprehensive study on bisphenol A and estrogenic activity in the Paraíba do Sul River, São Paulo, Brazil

Development of DRIP - drought representation index for CMIP climate model performance, application to Southeast Brazil

With the escalating impacts of drought events driven by climate change, reducing the uncertainty of drought projections becomes critical for enhancing risk management and adaptation strategies. This study aimed to develop an index for assessing the performance of CMIP6 Global Climate Models in simulating meteorological drought scenarios across regional hydrological systems, intended to provide more reliable information for management purposes. Named the ‘Drought Representation Index for CMIP Climate Model Performance’ (DRIP), this index evaluates CMIP models' performance to represent drought severity, duration, and return period. DRIP was used to select CMIP models and create an ensemble of the best-performing models (E-DRIP) to improve the reliability of drought projections. E-DRIP was then compared with a general ensemble of available CMIP6 models (E-CMIP). We applied this method in Southeast Brazil, a region known for its climate uncertainties and low predictability; specifically, it was implemented within the Paraíba do Sul River Basin, a nationally strategic watershed in a highly populated and industrialized area, which has recently faced unprecedented drought-related water crises. Results showed that DRIP effectively assessed the individual performance of CMIP models, which exhibited considerable variability, and identified the top-performing models for a multi-model ensemble. Additionally, the E-DRIP ensemble significantly reduced uncertainties in drought projections, achieving an average reduction of 63 % in the study area compared to E-CMIP. Furthermore, the proposed method enables evaluations across any standardized drought index scale, reference period, or threshold, and can be readily adapted to other hydrological systems.

The revelry of plastic! Quali-quantitative variation of microplastics in freshwater before and after Carnival in south-eastern Brazil

Context Pollution by synthetic polymers is even more problematic to the environment when this material is fragmented into small portions, forming microplastics (MPs). Aims We analysed the influence of the Brazilian Carnival on the abundance and richness of MPs in the Paraíba do Sul River (PSR). Specific objectives included classifying MPs by shape, colour and polymer, and quantifying and comparing the abundance and richness of surface-water MPs before, during and after Carnival. Methods Samples were taken from the superficial layer of the water column in 2023, by using manta net. Key results In total, 843 MPs were identified in the surface water of PSR. Higher MP concentrations were observed after the Carnival event than in the other two periods. Blue and black fibres were the predominant MPs. Glitter and sequin occurred only during the Carnival and post-Carnival periods. Polyester, polyamide and polyethylene were the most abundant in all the periods. Conclusions Our findings strongly indicated that Carnival represents a potential short-term source of MP introduction into the PSR basin. Implications A significant 170% increase in MP abundance was observed 10 days after the Carnival, which is an event occurring across multiple locations in the PSR basin.

Regional assessment of overwash processes in a retrograding sand barrier (Paraíba do Sul River Deltaic Complex, Rio de Janeiro, Brazil)

Storm events are the primary mechanisms for generating overwash along the shoreline. This process occurs when wave runup exceeds the elevation of sandy features, often forming washover deposits. In retrograding barriers, overwash is the main driver of landward migration. Extreme wave energy events can lead to rapid changes in the morphology of these environments. On urbanized coastlines, storm impacts can be catastrophic and result in high reconstruction costs. Understanding the characteristics of storm events and the local morphological characteristics of these sandy features is crucial for risk assessments, hazard mitigation, and coastal area adaptations in the scenario of increasing storm events. The main objective of this study is to analyze the role of overwash processes in the retrogradation of the Quissamã barrier, located in the southern sector of the Paraíba do Sul River Delta Complex (PSRDC), on the coast of Rio de Janeiro. Using data from the global Wave Watch III model, sea warnings issued by the Brazilian Navy, atmospheric pressure charts, and astronomical tides, we identified storm events and mapped the washover fans formed after specific storm events. The washover fans were identified using PlanetScope images. The identified storm events were characterized by waves from the SE-S directions with high peak periods, and mostly occurred during spring tides or transitioning to neap tides. Additionally, the atmospheric pattern for most events was associated with the migration of cold fronts from high to low latitudes, leading to the development of extratropical cyclones. The geometry of the barrier also proved to be an essential morphological pattern. Considering the relative sea level along part of the Brazilian coast has been decreasing over the last 5500 years, storm events and associated processes are crucial for the retrogradation of barriers, maintaining the retrogradational characteristics of this coastal barrier.

Barrier-lagoon system in the Paraíba do Sul River Deltaic complex (PARNA Jurubatiba, Brazil): Insights into mesoscale behavior and geological influence

Coastal barrier systems, identified by their morphostratigraphic characteristics, are classified under various nomenclatures, including barrier islands, spits, and barrier lagoon-systems, and are found along the shores of every continent on Earth. Geological, oceanographic, and morphological influences will shape their diversity, considering spatial and temporal scales. The geological approach, considered in conjunction with the mesoscale (decades to centuries) approach, provides crucial insights into understanding barrier behavior, especially in the context of climate change and future projections. In this context, this study aims to investigate the mesoscale behavior of barrier-lagoon systems in the Paraíba do Sul River Delta Complex (PSRDC), considering shoreline geomorphic responses and aspects of geological evolution. The geological approach was investigated using GPR profiles, AMS dating, and borehole. The historical approach was investigated by mapping shoreline dynamics from 1984 to 2020; beach profile analysis; and classification of geomorphic responses (1. Accretion/erosion due to anthropic influence; 2. Dynamic equilibrium; 3. Retreat; 4. In-place narrowing; 5. Landward rollover). The barrier lagoon system exhibits a morphostratigraphic signature of a retrogradational stacking patterns, which were already formed around 6700 years BP. The persistence of this morphostratigraphic characteristic to the present day underscores the importance of sediment supply compared to accommodation space creation rates in the evolution of these barrier lagoon systems in the PSRDC during the Late Holocene. At interdecadal and interannual scales, barrier retrogradation processes do not occur uniformly due to differences in storm wave propagation along the coast, morphological differences of the barrier, and the occurrence or non-occurrence of backbarrier lagoon reworking. Shoreline retreat is most pronounced in the central part of the barrier lagoon system, mainly between beach profiles P4 and P6, with rates ranging from −0.5 m.year−1 to −2.0 m.year−1. At the mesoscale, landward rollover geomorphic response was prevalent, indicating the potential for preserving barrier sediment volumes in the retrogradation process, due to overwash processes transferring sediments to the backbarrier. However, retreat and in-place narrowing responses were also detected in the central coastal area. These responses could lead to barrier narrowing and consequently render these areas more vulnerable to global climate change scenarios. In this regard, the significant role of the Restinga de Jurubatiba National Park (PARNA Jurubatiba) stands out, which could mitigate coastal squeeze effects.

Birds from human-modified Atlantic Forest landscapes of the middle-lower Paraíba do Sul River basin, southeastern Brazil

Birds from human-modified Atlantic Forest landscapes of the middle-lower Paraíba do Sul River basin, southeastern Brazil

Sustainability Indicators Applied to Water Resource Management: A Case Study of The Lower Course of The Paraíba do Sul River Watershed, Rio de Janeiro, Brazil

Objective: This paper presents an indicator system called "thrivability appraisal", developed based on the systemic view of the UN Sustainable Development Goals (SDG). This system combines seven dimensions of sustainability with principles of integrated and participatory water management. Theoretical Framework: The deprivation of resources, functions, and ecosystem services, which play a crucial role in the well-being and sustainability of communities, represents a challenge for development as established by the Millennium Summit. The publication of the United Nations' 2030 Agenda defined seventeen SDG, with the aim of promoting prosperity for all human populations. In the face of this challenge, water stands out as an essential chemical component for life, as well as for the health, well-being, and economic prosperity of populations. SDG 6 specifically addresses this issue, recognizing it as fundamental not only to achieve sustainability at the local, regional, and global levels but also to promote prosperity. Method: The thrivability appraisal methodology is based on an indicator system composed by 49 parameters chosen according to Ostrom’s seven sustainability principles. Secondary data from technical and academic documents were analyzed, complemented by primary data obtained through the environmental perception of representatives from the Watershed Committee of the IXth Hidrographic State Region (RH-IX). Results and Discussion: Water resources management sustainability evaluation in RH-IX revealed the existence of considerable challenges, as well as the need to strengthen participatory governance. Research Implications: The research showed that thrivability appraisal can be an important tool to suport decision-making definitions of the Committee.

Species boundaries of the whiptail catfish Rineloricaria (Siluriformes: Loricariidae) from the Paraíba do Sul River drainage, southeastern Brazil, with species redescriptions and description of a new species.

Species of the catfish genus Rineloricaria are common in the Paraíba do Sul River basin, in southeastern Brazil; here we present a revision of the taxonomic diversity and geographic distribution of the species of the genus inhabiting the basin, based on novel morphologic and molecular data. Five species delimitation methods based on cytochrome C oxidase subunit 1 nucleotide sequences yielded comparable molecular operational taxonomic units. The automatic barcode gap discovery, assemble species by automatic partitioning, barcode index number, and Bayesian implementation of the Poisson tree process methods supported the recognition of five evolutionary lineages. These taxonomic units were assigned to the previously described Rineloricaria nigricauda, Rineloricaria steindachneri, Rineloricaria zawadzkii, and Rineloricaria nudipectoris, and an additional undescribed species. R. zawadzkii was further divided into two intraspecific geographically structured lineages using the generalized mixed Yule coalescent delimitation method. A maximum likelihood phylogenetic analysis revealed that the five lineages from the Paraíba do Sul have closer relationships to different species from southern and southeastern Brazil (Ribeira de Iguape, Lagoa dos Patos, Uruguay, Paraguay, and Parana river basins) than to each other. Based on the analysis of lectotypes, recently collected material, and specimens from ichthyological collections, the poorly described R. nigricauda and R. steindachneri are redescribed following current descriptive standards. The undescribed species from the middle and upper Paraíba do Sul River basin is formally described. The description of a new species, along with the description of species boundaries in R. nigricauda and R. steindachneri, contributes to the knowledge of the ichthyofauna of the Paraíba do Sul River basin and adjacent coastal drainages of southeastern Brazil. An identification key for the species of Rineloricaria occurring in the Paraíba do Sul River basin is provided.

CHARGES FOR THE USE OF RAW WATER: AN ANALYSIS OF THE PERFORMANCE OF MODELS APPLIED IN WATERS UNDER FEDERAL DOMAIN IN THE CUREMA-MÃE D'ÁGUA WATER SYSTEM

Aiming to explore the potential fundraising, models used for charging the raw waters of São Francisco, Paraíba do Sul, and Doce rivers were applied and evaluated in the Curema-Mãe D'Água water system, located in semiarid Brazil. The methodology consisted of a bibliographical review, documentary research, system operation modeling, application of models, and critical analysis of operations and collections results, comprising a total of 240 months from 2002 to 2021. When applying the Standard Operational Policy (SOP), the water system did not meet the demands 35.4% of the time. The model with the highest collection was the one used in Paraíba do Sul River (R$ 12.71 million/year). The models applied in São Francisco (R$ 1.37 million/year) and Doce Rivers (R$ 3.58 million/year) presented the lowest collections. The Paraíba do Sul River model provided the highest charging with water abstract and consumption elements. The Doce River model, conversely, delivered the highest values through the effluent discharge element. The analysis of charging results indicates that each model has specific applications and outcomes. None of the models consider eventual water scarcity conditions in their formulations.

Analysis of extreme rainfall and landslides in the metropolitan region of the Paraiba do Sul River Valley and North Coast of Sao Paulo, Brazil

Analysis of extreme rainfall and landslides in the metropolitan region of the Paraiba do Sul River Valley and North Coast of Sao Paulo, Brazil

Evaluation of Cumulus and Microphysical Parameterization Schemes of the WRF Model for Precipitation Prediction in the Paraíba do Sul River Basin, Southeastern Brazil

Evaluation of Cumulus and Microphysical Parameterization Schemes of the WRF Model for Precipitation Prediction in the Paraíba do Sul River Basin, Southeastern Brazil

Enhancing short-term streamflow forecasting of extreme events: A wavelet-artificial neural network hybrid approach

Accurate short-term streamflow forecasting models are crucial for effective water resource management, enabling timely responses to extreme flood or drought events and mitigating potential socioeconomic damage. This study proposes robust hybrid Wavelet Artificial Neural Network (WANN) models for real-world hydrological applications. Two WANN variants, WANNone and WANNmulti, are proposed for short-term streamflow forecasting of extreme (high and low) flows at eight gauging stations within Brazil's Paraíba do Sul River basin. WANNone directly feeds both the original streamflow data and the decomposed components obtained through an À Trous wavelet transform into the ANN architecture. Conversely, WANNmulti utilizes separate ANNs for the original data, with the final streamflow estimate reconstructed via the inverse wavelet transform of the individual ANN outputs. The performance of these WANN models is then compared against conventional ANN models. In both approaches, Bayesian optimization is employed to fine-tune the hyperparameters within the ANN architecture. The WANN models achieved superior performance for 7-day streamflow forecasts compared to conventional ANN models. WANN models yielded high R2 values (>0.9) and low MAPE (4.8%–14.7%) within the expected RMSE range, demonstrating statistically significant improvements over ANN models (71% and 75% reduction in RMSE and MAPE, respectively, and 69% increase in R2). Further analysis revealed that WANNmulti models generally exhibited superior performance for low extreme flow predictions, while WANNone models achieved the highest accuracy for high extreme flows at most stations. WANN models' strong performance suggests their value for real-time flood warnings, enabling improved decision-making in areas like flood/drought mitigation and urban water planning.

The use of Computational Modeling for Simulation and Comparison of Digital Elevation Models in Northwest Fluminense. Case Study: Pomba River and Paraíba do Sul River

Purpose: The work proposes the location, simulation and comparison of Digital Elevation Models (DEM) in a section where the Pomba River and the Paraíba do Sul River meet, located in the northwest of the state of Rio de Janeiro, a region known for the reproduction of some species of fish threatened with extinction. Methods: Searches for DEMs in the region were carried out on a free website, where a total of 10 DEMs were found. Several hydraulic simulations were carried out using computer modeling software called Iber, to verify the veracity and coherence of the data available. Results and conclusion: After simulating all DEMs, it was found that the DEM that best represented the study region, with greater coherence in topography and hydraulics, was the DEM provided by Copernicus with a 5m lowering. Research implications: Hydraulic simulations are fundamental for preventing dangerous situations for society as a whole. Together with the studies carried out through simulations, it is possible to analyze their hydraulic and topographic coherence for the flow of rivers and also their floodability for urbanized/dry regions. Originality/value: Verification of the coherence of data provided by the Open Topography website using Iber software, as a method of preventing hydraulic disasters (floods).

LAGOA SALGADA: AN OVERVIEW OF A BRAZILIAN HYPERSALINE LAGOON ENVIRONMENTAL STUDIES OVER THE LAST 5000 YEARS USING RADIOCARBON DATE CORRECTIONS

ABSTRACTThe Lagoa Salgada is located in the Paraíba do Sul river delta plain on the coast of Rio de Janeiro state, Brazil, and is one of the few lagoons in the world that have well-developed recent stromatolites. Lagoa Salgada is a hypersaline lagoon formed in a very complex environmental system subjected to terrestrial and oceanic influences under different sea level regimes and climate variations. In addition, sediment and stromatolites are characterized by unusually positive inorganic δ13C VPDB values. For this reason, it has been the target of several geological and paleoenvironmental studies, which, in their great majority, require a geochronological technique in order to determine the changes in the environment over time. When radiocarbon (14C) dating is used, it is necessary to consider some details as the source of 14C in the environment and perform 14C ages calibration accordingly. In the present paper, a bibliographic survey was carried out in order to review the data treatment and improve the environmental evolution discussion based on accurate calibration. Using the Marine20 curve and an undetermined ΔR, we generated growth and depositional models to establish an overview of the formation of this lagoon.

Inter-basin water transfers under changing climate and land use: Assessing water security and hydropower in the Paraíba do Sul River basin, Brazil

The intensification of climate extremes and land uses poses a major challenge for water managers, especially in heavily populated basins with large reservoirs, multiple uses, and inter-basin transfers. In this study, we analyzed water security in the Paraíba do Sul River basin, responsible for supplying a significant fraction of the needs of Brazil's two largest metropolitan areas through water transfer. Unless existent studies emphasize aspects of water scarcity disregarding other competitive water use, we considered the impacts on hydropower generation in a fully integrated modeling framework, which includes reservoir operation rules. To achieve this, we integrated future projections of land uses, global climate change (RCP 4.5 and RCP 8.5), and water demand for the period 2016–2055. Most of the climate change scenarios suggested a reduction in the frequency of both high and low flows, by nearly 25%, which resulted in an increase in flow regularization in the main basin's reservoirs. An undesirable consequence of those trends was the reduction of hydropower generation. Regarding water supply to the metropolis outside the basin, results indicated a possibility of a more contentious water governance scenario. The long-term sustainability of the basin's water resources will require implementing policies to enhance water use efficiency and reuse, in combination with other renewable energy sources.

Phylogeography, genetic diversity, and intraspecific genetic structure of the black-horned capuchin (Sapajus nigritus).

Recent molecular studies have clarified the overarching taxonomy of capuchin monkeys, but intraspecific genetic diversity remains unexplored for most capuchin species. One example is Sapajus nigritus, the southernmost capuchin monkey, found in Brazil and Argentina; its phenotypic diversity has been recognized as two geographic subspecies, but the intraspecific genetic structure of this taxon is poorly known. Here, we sampled across most of this species' geographic distribution, producing a newly sequenced data set for genetic analyses that included 78 individuals from 14 populations. We investigated the intraspecific diversity, genetic structure, and evolutionary history using three mitochondrial markers. Our results indicated that S. nigritus populations exhibited high levels of genetic structure. We found strong support for two monophyletic clades within this species with a deep phylogenetic split, and clear separation from other related taxa. Vicariance events seem to have played a prevalent role in shaping S. nigritus genetic differentiation. The Paraíba do Sul River may have driven the deep divergence between southern and northern clades, whereas the Tietê River may have had a weaker, more recent effect on the divergence of populations within the southern clade.

Temporal evolution of suspended solids in the management of medium-sized watersheds in the Metropolitan Region of Paraíba Valley

The demand for water to meet the needs of the population has increased with the rapid growth of urban centers. The urban expansion in Taubaté (23.03º S, 45.55º W) negatively impacts the Una River Basin, a significant tributary of the Paraíba do Sul River, resulting in issues of sedimentation, siltation, and flooding. Systematic monitoring of sediment characteristics in human-influenced areas allows for an understanding of water quality variations, watershed diagnosis, and analysis of impacts on aquatic ecosystems, with total suspended solids (TSS) being a widely used parameter in this context. This study investigated the temporal evolution of the TSS concentration in the Una River, highlighting the importance of sound management practices to reduce sedimentation in urban catchments, through the analysis of biochemical parameters obtained from the Cetesb/Infoaguas platform. From 2008 to 2022, lower TSS concentrations were observed in winter (86.2 ± 35.6 mg L-1), while higher values were obtained in summer (779.7 ± 1024.8 mg L-1). In general, statistically significant correlations were found at the 95% confidence level between TSS and turbidity (Pearson's r = 0.93), dissolved oxygen (Pearson's r = -0.46), and electrical conductivity (Pearson's r = -0.43), while other evaluated parameters (pH, dissolved solids, and precipitation) did not show significant correlations. Among the key findings, it is crucial to study the temporal evolution of TSS and to implement sustainable management strategies in urban catchments, including erosion control measures and stormwater management, to preserve water quality, aquatic ecosystems, and water supply in the urban communities of RMVale.
 Keywords: basin, management strategies, sustainable, total suspended solids.

The influence of climate parameters on fires in the Paraíba do Sul River valley, southeast Brazil

Brazilian biomes have been experiencing an increase in fires during the whole year, but fires increase substantially during drier periods. Several indexes might be good indicators of the severity of the droughts, such as The Rainfall Anomaly Index (RAI), Standardized Precipitation Index (SPI) and the Vegetation Health Index (VHI). This study therefore aimed to understand the dynamics of climate, using some indexes and fires in Paraíba do Sul River Valley, Paulista portion, to verify whether fire is more likely to spread in hotter and drier years. We hypothesized that fire events are more frequent and burned areas are larger in hotter and drier years in the region. By conducting a cross-correlation analysis and separating the monthly data into dry and rainy seasons, it was possible to establish a correlation between climate parameters and fire. A significant correlation was found between RAI and fires in both seasons. Additionally, we observed that high occurrences of fire events and burning areas were more explained by RAI, VHI and SPI-3 in dry and wet seasons than by temperature and SPI-1, SPI-6 and SPI-12. We noticed a complex dynamic between fire events, burned area, the environment, and climatic variables. However, the studied indexes proved to be effective tools for detecting drought conditions in the region and their relationship to fire.
 Keywords: burning, climatic indexes, Paraíba do Sul River Valley.

Hidden diversity and evolutionary diversification in Phalloceros harpagos Lucinda (Cyprinodontiformes: Poeciliidae)

AbstractThe distribution of Phalloceros species is generally allopatric and restricted; however, Phalloceros harpagos has a wide distribution and exhibits morphological variation among populations from different Brazilian river basins. Different species delimitation tests using cytochrome C oxidase subunit I gene sequences indicated that P. harpagos is a species complex that comprises between 7 and 9 phylogroups. The separation of the Paraná and Paraíba do Sul River basins most likely caused the diversification of these phylogroups in the Miocene period. The majority of phylogroups have a narrow distribution; however, one phylogroup has a broad distribution, being found primarily in the Paraná, Ribeira de Iguape, and Iguaçu River basins. This distribution can be attributed to possible headwater capture events caused by the reactivation of faults and erosion in the quaternary. Estimates about the times of divergence based on molecular data could be used to infer the biogeographic processes related to the diversification of South American freshwater fish.

Variations in benthic foraminifera biofacies since Mid-Pleistocene (MIS 7) in the Campos Basin slope, Eastern Brazil: Assessing present-day and past controlling factors

Benthic and planktonic foraminifera faunal and stable isotopic (δ18O and δ13C) analyses on foraminiferal tests were carried out on a piston core, collected from the Campos Basin slope at a water depth of 1475 m. The core location is in front of Cape São Tomé and exhibits landslide scars features. Benthic foraminifera biofacies with ecological indexes and statistics, lithological facies, biostratigraphy and stable isotopic analysis were used to understand the paleoenvironmental evolution of the region by comparison with modern foraminiferal assemblage. Six biofacies were identified between Marine Isotope Stage (MIS) 7 to MIS 1. The main ecological factors controlling the modern assemblages are: bottom currents, slope stability, oxygen concentration, and nutrient input. However, the last two factors are linked to oceanic processes associated with the Paraíba do Sul river, the influence of which has changed in the past. In particular, Biofacies 3, contains infaunal species, points to dysoxic or anoxic periods in the environment, which are interpreted as periods of increased river influence. Changing environmental conditions were observed as the dominant benthic foraminifera species varied down the core, from Epistominella exigua that thrives in stressful conditions, such as sea level oscillations to Globocassidulina crassa, that prefers mild environments during periods of sea level stability.