Revista Ambiente & Água - An Interdisciplinary Journal of Applied Science

1-12

Authors: Bruna Ferreira dos Anjos; Tatiane Kelly Barbosa de Azevêdo; Bruna Rafaella Ferreira da Silva; Renata Martins Braga; Alexandre Santos Pimenta; Francisca Adriana Ferreira De Andrade

Concern about the overexploitation of natural resources has increased in recent decades, especially involving water and its treatment. Paradoxically, one of the sources of water pollution is the treatment itself, due to the use of chemical flocculants, which end up generating sludge that may be highly aggressive to the environment. One of the ways to solve this problem is to use natural flocculants for this purpose, since they are biodegradable and do not harm nature. This study evaluated the efficiency of a natural flocculant produced from tannins extracted from the bark of the cashew tree (Anacardium occidentale) and compared it with two commercial coagulants, Tanfloc® and iron chloride. The water for treatment was collected from a weir. The cashew trees’ bark was collected, ground, and submitted to hot-water extraction to yield the tannins, and the extraction product was cationized. The flocculation tests were carried out using the jar test with solutions having concentrations of 33.3, 66.7, and 100 mg L-1. Turbidity and pH were analyzed before and after flocculation. Among the assessed flocculants, the cationized tannins produced the best responses both for removal of turbidity and final pH of the treated water. Tanfloc® also produced satisfactory results regarding turbidity removal. The iron chloride, besides not properly clarifying the water, left it very acidic. Since the cationized tannins practically did not change the pH and were effective in the removal of turbidity, they represent an interesting, sustainable alternative product to treat the water.

1-11

Authors: Natasha Berendonk Handam; Ana Beatriz Loureiro Gonçalves da Silva; Rodrigo Bezerra da Silva; Priscila Gonçalves Moura; Elvira Carvajal; Adriana Sotero-Martins; José Augusto Albuquerque dos Santos

Reused water is produced from treated effluents, and can be an alternative source of water for agriculture. However, its quality must be assessed to avoid causing damage to human and environmental health. This study evaluated the sanitary quality (bacteriological and physicochemical) of reused water samples for agricultural irrigation, compared with those described in Brazilian and international regulations. Bacteriological analyses were performed, and the results were compared with the norm of the Brazilian Association of Technical Norms (ABNT) NBR nº 13.969/1997. Physical and chemical analyses of the reused water samples were carried out, and the results were compared with the standards described by regulations: Resolution of the State Council for the Environment of Ceará No. 2 of 2017; Resolution of the Bahia State Water Resources Council No. 75 of 2010; and “Guidelines for Water Reuse” from the U.S. Environmental Protection Agency - EPA. According to Brazilian regulations, bacteriological analyses showed that the "chlorinated" and "polished" samples were suitable for agriculture. However, the “biological" sample was unsuitable for use, and showed a high level of thermotolerant coliforms (25.800 CFU / mL). According to bacteriological and physical-chemical analyses, the “polished” sample was only proper for agriculture irrigation. Therefore, the work suggests the creation of federal law regarding agricultural reuse to control the sanitary quality of water for human and environmental health.

1-16

Authors: Beatriz Milz; Patricia Oliveira de Aquino ; Jean Carlo Gonçalves Ortega; Ana Luisa Vietti Bitencourt; Cristina Souza Freire Nordi

The Billings Reservoir is an important water body for public supply of the Metropolitan Region of São Paulo, Brazil, and water captation for public supply is located in the Rio Grande environmental compartment. This article evaluates the water quality of the environmental compartment Central Body I of the Billings Reservoir, which receives the reversed waters from the polluted Pinheiros River, at four sampling points with different contributions from the surroundings, seeking to verify the influence of seasonality on water quality and whether there was a difference in water quality between the sampling points. Water sampling was carried out on the surface at four points, in a longitudinal profile, covering two periods (dry and rainy) distributed in six samplings between 2016 and 2019. Analyzed variables included temperature, dissolved oxygen, pH, electrical conductivity, chlorophyll-a and nutrients (phosphorus and nitrogen). Space-Time Interaction tests revealed that physicochemical variables did not vary due to the interaction between sampling periods and points, but several variables varied significantly during the sampling period. The results of the Trophic State Index show that waters of Central Body I are classified as Hypereutrophic, highlighting the degradation of water quality in this compartment. This research will better inform public managers and assist their efforts to minimize and mitigate the effects of progressive water quality degradation in this reservoir.

1-11

Authors: Willian dos Santos Oliveira; Elias Silva de Medeiros; Alessandra Querino da Silva ; Luciano Antonio de Oliveira

Precipitation is an important object of study and plays an important role in the dynamics of rainfall distribution in a region. This study investigated the spatial and temporal variation of precipitation in the São Francisco River Basin (SFRB). A historical series of data from 1989 to 2018 was analyzed, and a random function was decomposed into trend and residual components for analysis of precipitation. Interpolation techniques were used to analyze precipitation spatial behavior over time, using high-resolution precipitation maps. Our results showed that the exponential model prevailed in four periods. The findings also showed a high precipitation variability in the SFRB and enabled us to monitor precipitation behavior over the years, as well as in the different sub-regions in SFRB. Finally, important information was obtained, enabling, for instance, the identification of vulnerable areas suffering from lack of rainfall.

1-10

Authors: Jayson Baldera Saavedra ; Lisbet Judith Noriega Pérez; Claudio Eduardo Quiñones Cerna; José Alfredo Cruz Monzón; Fernando Javier Hurtado Butrón; Mario Esparza Mantilla

Bioelectroremediation (BER) uses electrical current to stimulate catabolism of environmental pollutants, such as petroleum spills. However, applying current to soil may have adverse effects on the microorganisms involved in petroleum degradation. We identify and evaluate the BER capabilities of a strain of Aspergillus niger obtained from petroleum-contaminated soil. Spores of this strain immobilized in alginate spheres (2 g) were mixed with 100 g of hexadecane-contaminated sandy loam soil and exposed to 5, 10, or 15 mA direct current in a 200 cm3 cell with copper electrodes. Soil hexadecane concentration was measured by gas chromatography. More than 94% of hexadecane was removed from the soil within 12 days for the currents tested, and the A. niger grew to 6 x106 CFU g-1 in 15 days at 10 mA current. The maximum hexadecane degradation was achieved using a 10-mA current for 20 days, but more than 99% of the hexadecane was removed by the fifth day. These results suggest that the use of spore-containing alginate beads promotes growth and petroleum biodegradation of A. niger exposed to electrical currents.

1-16

Authors: Diêgo Gomes Júnior; Marcos Vinicius Winckler Caldeira; Dione Richer Momolli ; William Macedo Delarmelina ; Henrique Machado Dias; Ranieri Ribeiro Paula; Kelly Nery Bighi

Litter dynamics is one of the fundamental processes for the growth and maintenance of native forest fragments, being considered the main pathway for nutrient cycling in forests. Therefore, studies on accumulated litter and nutrient content provide information for a better understanding of nutrient dynamics. The aim of the study was to evaluate leaf litter and nutrient stock in different seasons and the instantaneous rate of decomposition in an Atlantic Forest Fragment over two years. Litter sampling was carried out in 12 permanent plots with dimensions of 20 m x 50 m. Litter dry mass and nutrient concentration were determined. The average annual accumulation of litter was 5269 kg ha-1. There was no statistically significant difference in the amount of litter between seasons. There was a statistically significant difference in the contents of N, P, K Ca and Mg between the different seasons. Nutrient stocks were 123.3, 92.8, 13.2, 11.8, 9.6, 3.0 kg ha-1 year-1 for Ca, N, Mg, S, K and P respectively. The total of nutrients in the accumulated litter was 253.7 kg ha-1 year-1. The litter renewal time was 281 days. The times required for 50% and 95% litter decomposition were 196 and 850 days. The average litter stocks, nutrients and decomposition are in line with other studies, indicating that the Atlantic Forest fragment seasonal semi-deciduous presents indicators of nutrient cycling. These results show that the ecosystem is sustainable from the point of view of cycling and nutrient release.

1-18

Authors: Julio César Bizarreta Ortega; Marko Antonio Lopez Bendezu; Alexandre Almeida Del Savio; ‪Fausto Alfredo Canales

Studies concerning the debris flows in mountain areas are relevant because of their potential negative effects on the human communities and infrastructure in their areas of influence. To advance the understanding of the theoretical basis, this study qualitatively analyzes the effect of lithological characteristics and soil type on the generation of debris flows in the arid basin of Mirave, in southern Peru, as a consequence of extensive rainfall. Two debris flow events are evaluated, which occurred in the studied area in March 2015 and February 2019. The method used to achieve the objective combines the use of satellite images, field data collection, and lab tests results to estimate the relative importance of the abovementioned characteristics in the generation of debris flows. The results suggest that the poor presence of clay and the predominance of sandy-loamy structured soils in the Mirave Basin make them unstable when erosion occurs. In addition, the features of broken down materials generated from residual and colluvial soils in the primary area of study are one of the main causes of debris flows in the region.

1-9

Authors: Arnulfo Antonio Tarón Dunoyer; Luis Enrique Guzmán Carrillo ; Rafael Emilio González Cuello

Many substances of plant origin are extracted for use in the primary treatment of domestic wastewater. In most cases, they are used as coagulating and flocculating agents and are derived from seeds, leaves, bark or sap, roots, and fruits of trees and plants. In this research, the use of Cassia fistula seed was evaluated for the removal of turbidity and color in domestic wastewater from a pumping station in the city of Cartagena (Colombia). The optimal dose of C. fistula seed powder was determined by jar test using an E&Q F6-300 digital flocculator. Physicochemical parameters such as turbidity and color were determined, following the recommendations of APHA (Standard Methods for Water and Wastewater), expressing the results in UNT (Total Nephelometric Units) for turbidity, and UPt-Co (Platinum-Cobalt Units) for the color. The results obtained show that with a dose of 160 mgL-1 of the coagulant extracted from the C. fistula seed, a value of 34.14 NTU is reached for removal of 62.18% with respect to the initial turbidity value. The color decreases reaching a minimum value of 88.59 UPC for removal of 64%, at a dose of 160 mgL-1 of natural coagulant. The seed C. fistula exhibited good coagulating properties at low doses and can be an important alternative for the removal of color and turbidity in wastewater.

1-14

Authors: Juan José Humanante Cabrera ; Lucrecia Cristina Moreno Alcivar ; Carlos Alberto Deza Navarrete; Ana Mercedes Grijalva Endara; Juan Humanante Moreno; Joan Alberto Suárez Tomalá

This research evaluated the wastewater treatment system of the Punta Carnero sector, in relation to pollutant efficiency load removal, final effluent quality and impact on the ecosystem, and finally to determine if the final discharge can be reused for agricultural irrigation. The research was based on the affluent and effluent characterization of the system, carried out in three phases: i) Taking of simple samples, analyzed in an accredited water laboratory and analysis of the contaminant loads efficiency; ii) Review of results compared to the Table of “Discharge limits to a freshwater receiving body”; iii) Examination of results based on the “Water Quality Criteria for Agricultural Irrigation” Table of the Ecuadorian regulation TULSMA (2015). BOD (62.42%), COD (62.41%) and FC (53.58%) removal efficiencies did not comply with current Ecuadorian regulations. The quality of the effluent with respect to the parameters evaluated for discharges to a freshwater receiving body denoted a non-optimal quality of final discharge, negatively impacting the ecosystem. Finally, the evaluation determined parameters that exceed the water quality criteria for agricultural irrigation allowed: Oils-Fats (5.65 mg/l), FC (62,900 NMP/100ml), Hg (0.00141 mg/l), OD (8.86 mg/l). After evaluating the wastewater treatment system, it was determined that the pollutant load removal efficiency and effluent quality is not optimal for discharge into a receiving water body, so it’s not suitable for reuse in agricultural irrigation.

1-19

Authors: Vinícius Siqueira Oliveira Carvalho; Lívia Alves Alvarenga; Pâmela Aparecida Melo; Javier Tomasella; Carlos Rogério de Mello; Minella Alves Martins

Changes in precipitation and air temperature may produce different impacts on the hydrological regime, compromising water supply. This study focuses on climate change impacts in the Verde River Basin (VRB), a tropical headwater basin in southeast Brazil, located in the state of Minas Gerais. The Variable Infiltration Capacity model (VIC) was calibrated and validated in the Verde River Basin. The downscaling (Eta Regional Climate Model, at 20-km resolution) of three Global Circulation Models (CanESM2, HadGEM2-ES and MIROC5) were used to drive the VIC for a historical baseline (1961-2005) and three time-slices (2011-2040, 2041-2070 and 2071-2099), under RCPs 4.5 and 8.5 scenarios. The scenarios were used as input in the hydrological model after bias correction. The hydrological model (VIC) showed satisfactory statistical performance in calibration and validation, with CNS varying from 0.77 to 0.85 for daily and monthly discharges; however, it overestimated some peak flows and underestimated the recession flows. Multi-model ensemble means predict increases of the minimum and maximum monthly average temperature for the investigated area at the end of the century. The Eta-CanESM2 indicated greater warming, mainly for RCP8.5 at the end the century, whereas Eta-HadGEM2-ES showed higher reduction in the precipitation for RCP4.5 at the beginning of the century and for RCP8.5 at the end the century, negatively impacting the evapotranspiration and discharge. Among the Regional Climate Models (RCMs), the Eta-MIROC5 showed minor changes in the components of the hydrological cycle. This study suggests that Global Circulation Models represent an additional uncertainty, which should be accounted for in the climate change impact assessment.

1-16

Authors: Alpina Begossi; Svetlana Salivonchyk; Branko Glamuzina; Alessandro Alves-Pereira; Carlos Eduardo De Araujo Batista; Regina Helena Geribello Priolli

There are gaps in our knowledge of important fish consumed by people in tropical countries. Small-scale fisheries are difficult to regulate, especially in countries with no species monitoring. At Copacabana (Rio de Janeiro), we observed 490 individuals of badejo (Comb grouper) (Mycteropeca acutirostris in 2013-2014 and in 2018-2020. The average catch was 1.36 kg (n=466 individuals). A pattern of decreasing catches was observed for Comb grouper. Therefore, provided that the fishing gear and the number of fish have remained the same, the apparent decrease in Comb grouper needs to be further investigated. The results provide information about the major spawning season, around spring (September-December) with additional spawning during April. Genetic analyses in samples from 96 grouper obtained along the coast of Brazil were conducted. The Single Nucleotide Polymorphism (SNP) loci obtained for grouper species enabled us to determine the relative genetic proximity of M. acutirostris and Mycteroperca bonaci, information that can be useful for aquaculture and conservation. The objectives of this study were: a) to obtain data about the fishing activity (catch landings) of Comb groupers at Copacabana, Posto 6; b) to verify the reproductive period of Comb grouper, throughout the year, through the catches from the fishery; c) to develop a large numbers of SNP markers, which can be useful to studies about grouper populations (Mycteroperca and Epinephelus); and, d) to obtain data on the price of the Comb grouper. This study contributes data on the fishery and on the biology and ecology of groupers, and further contributes to conservation efforts.

1-16

Authors: Carolina Almeida Lopes ; Cely Roledo ; Adriano Gonçalves dos Reis

M. ole·ifera se·ed hu·sks (H-M·O) w·ere u·sed as adsorbent for the removal of methylene blue (MB) dye from an aqueous solution. The ads·orbent was char·acterized by SE·M, ED·X, X·RD, F·TIR, B·ET, and p·HPZC. To evaluate adsorption capacity, the influences of p·H, kinetics, isotherms, and thermodynamic prop·erties were anal·yzed. Characteri·zation tech·niques indic·ated that H-MO has het·erogeneous morp·hological charac·teristics wi·th a spe·cific sur·face a·rea of 3.24 m2 g-1, mai·nly comp·osed of ce·llulose distr·ibuted in an amor·phous stru·cture. MB adsorption was favorable at pH values higher than pHPZC of 6.6, using an adsorbent dosage of 1.0 g L-1. Equilibrium was achieved in the first 240 min, and the pseudo-second-order model was suitable for describing the kinetic data. Freu·ndlich was the mo·st adeq·uate model for descri·bing the isoth·erm cur·ves, pred·icting a max·imum adsor·ption capa·city of 122.7 mg g-1 at 24°C, hig·her tha·n oth·er natu·ral ad·sorbents. The ads·orption proc·ess w·as spo·ntaneous and exoth·ermic, indic·ating that lo·wer temper·atures fav·or the ad·sorption and th·at it is cont·rolled by p·hysical fo·rces. The da·ta presen·ted indic·ate the M·B has t·he pot·ential to be succ·essfully trea·ted by the eco-fr·iendly and l·ow-cost ads·orbent M. oleif·era seed h·usks.

1-20

Authors: Agus Tjahjono ; Rudy Sugiharto ; Okvita Wahyuni

This research (1) analyzed the content of Pb and Cd in water and sediment; (2) analyzed physical and chemical parameters in water; (3) determined the enrichment factor and accumulation index of Pb and Cd in sediments; and (4) to identified water quality based on the Pollution Index (IP) and STORET. The analysis was carried out using PCA (Principal Component Analysis) and Pearson's correlation, and was conducted in the downstream section of the Musi River, Palembang, using a random sampling technique. Based on the analysis, it was found that the content of Pb and Cd in the waters had surpassed the quality standard whereas the contents of both heavy metals found in the sediment still met the quality standard. It was also found that several variables of the physical and chemical parameters did not meet the criteria. Based on the Enrichment Factor (EF) and the Accumulation Index (Igeo) of Pb and Cd, the river had not been defiled. The pollution index values of both IP and STORET indicated that the water had been heavily polluted. Based on the PCA, three factors which affected the quality of the river water were found.

1-11

Authors: Daniel Andrioli de Lima; Guilherme Theodoro Nascimento Pereira de Lima; Vitor Eduardo Molina Júnior; Laura Maria Canno Ferreira Fais

Dams pose a high potential risk due to the possibility of rupture. An accident can cause severe consequences for the economy and the environment, besides the loss of human lives. In addition to large dams for power generation, there are also a large number of small earth dams throughout the world, mainly in rural areas, built for the purpose of irrigation or watering animals. Problems with small dams are also frequent, especially in periods of high rainfall when they are more prone to failure. When dams are in cascade, the probability of a rupture is even greater than with an isolated dam, since in most cases small dams do not have enough freeboard to contain the volume coming from the dam further upstream. However, Brazilian legislation relating to water dams only covers the large ones, unless they are classified with high Hazard Potential (DPA for its acronym in Portuguese). Thus, there is no specific legislation for small dams, which means that many of them do not undergo regular inspections and proper safety assessment. This work aims to apply the simplified classification developed by the National Laboratory of Civil Engineering (LNEC for its acronym in Portuguese) for dams in cascade and to compare it to the classification of the Brazilian law for the DPA, evaluating its applicability for small dams. In this way, this method will complement and facilitate decision-making by owners and regulators, thus allowing special attention to the safety of small dams all over the world.

1-11

Authors: Anderson Nascimento do Vasco; Amanda Vaz de Souza Oliveira; Geovane Alves Feitosa; Talita Guimarães Araújo-Piovezan; Agripino Emanuel Oliveira Alves; José Oliveira Dantas

River regularization plays an important role in socio economic development. However, it also modifies the natural flow system of the river and its biotic and abiotic characteristics, causing significant impacts on rivers. To evaluate the impacts on the macroinvertebrate community caused by dam construction on the Poxim-Açú River, metrics of composition and community structure of the macroinvertebrates were analyzed, as well as ecological and biological traits of the region. Macroinvertebrates were collected at three sites located downstream the dam, before (2013) and after (2015) dam construction. The water quality was classified as “good” to “excellent” according to the biotics indices. The alterations of the flow regime of the river after the dam construction influenced the macroinvertebrate communities, modifying their diversity, equitability, richness, and the number of individuals.

1-14

Authors: Evandro Manoel da Silva ; Hans Raj Gheyi ; Reginaldo Gomes Nobre ; Geovani Soares de Lima; Lauriane Almeida dos Anjos Soares; Benedito Ferreira Bonifácio

This study evaluated the influence of combinations of nitrogen and potassium doses on the physiology and fruit production of West Indian cherry irrigated with waters of different salinities in the second year of cultivation. The experiment was conducted in the municipality of Pombal-PB, Brazil, in plastic containers adapted as lysimeters installed in the field, in a randomized block design, 5 x 4 factorial scheme corresponding to five levels of electrical conductivity of irrigation water (ECw): 0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1, and four combinations of nitrogen and potassium fertilization: 70% N + 50% K2O; 100% N + 75% K2O; 130% N + 100% K2O and 160% N + 125% K2O of the dose recommended for West Indian cherry, with three replicates and one plant per plot. The cv. ‘Flor Branca’ was grafted on the cv. ‘Junco’, between 420 and 550 days after transplanting. Nitrogen and potassium combinations did not mitigate the deleterious effects of water salinity on the physiology and fruit formation of West Indian cherry. An increase in ECw intensifies the intercellular electrolyte leakage and reduces the water potential in the branch, chlorophyll content in the leaves, CO2 assimilation rate, equatorial and polar diameters as well as the mass of fruits. Fertilization of plants with 70% N + 50% of K2O, compared to the other fertilization combinations, causes less intercellular electrolyte leakage and promotes higher CO2 assimilation rates, higher chlorophyll content in leaves, and fruits of larger size and mass.

1-19

Authors: Jéssica Assaid Martins Rodrigues ; Marcelo Ribeiro Viola; Carlos Rogério de Mello; Marco Antônio Vieira Morais

The Brazilian Cerrado biome is the largest and richest tropical savanna in the world and is among the 25 biodiversity hotspots identified worldwide. However, the lack of adequate hydrological monitoring in this region has led to problems in the management of water resources. In order to provide tools for the adequate management of water resources in the Brazilian Cerrado biome region, this paper develops the regionalization of maximum, mean and minimum streamflows in the Tocantins River Basin (287,405.5 km2), fully located in the Brazilian Cerrado biome. The streamflow records of 32 gauging stations in the Tocantins River Basin are examined using the Mann-Kendall test and the hydrological homogeneity non-parametric index-flood method. One homogeneous region was identified for the estimate of the streamflows Qltm (long-term mean streamflow), Q90% (streamflow with 90% of exceeding time), Q95% (streamflow with 95% of exceeding time) and Q7,10 (minimum annual streamflow over 7 days and return period of 10 years). Two homogeneous regions were identified for maximum annual streamflow estimation and the Generalized Extreme Value distribution is found to describe the distribution of maximus events appropriately within the both regions. Regional models were developed for each streamflow of each region and evaluated by cross-validation. These models can be used for the estimation of maximum, mean and minimum streamflows in ungauged basins within the Tocantins River Basin within the area boundaries identified. Therefore, the results provided in this paper are valuable tools for practicing water-resource managers in the Brazilian Cerrado biome.

1-15

Authors: Gian Carlos Poleto; Dione Richer Momolli; Mauro Valdir Schumacher ; Aline Aparecida Ludvichak ; Kristiana Fiorentin dos Santos; Márcio Viera ; Clayton Alcarde Alvares; James Stahl

Given that atmospheric deposition is the first source of nutrient input into forest ecosystems, and that the precipitation partition serves as a nutritional source mainly when there is an interaction with the forest canopy, the objective of the present study was to quantify the nutrients input into rainfall, throughfall and stemflow in Eucalyptus urophylla stands with partial exclusion (E) and without exclusion (WE) of throughfall. The experiment was conducted in the northeast of the state of Paraná-Brazil, in the municipality of Telêmaco Borba. The partial precipitation exclusion system (E) is formed by a system of gutters that conduct 30% of throughfall out of the experiment. The nutrient input in rainfall was 55.7 kg ha-1 yr-1, while the sum of throughfall and stemflow was 64.1 kg ha-1 yr-1 in treatment (WE) and 39.8 kg ha-1 yr-1 in treatment (E). Interaction with the canopy of the trees enriched the rainfall with nutrients, mainly the elements potassium and chlorine, due to leaching of the vegetal tissues. The reduction of the water treatment system in partial exclusion of precipitation (E) reduced representative nutrient input. Although stemflow represents on average only 2.6% of the water volume, it is responsible for 6.7% of the amount of nutrients in relation to precipitation. Therefore, stemflow cannot be neglected in the balance of nutrient cycling. With a rotation of 7 years, the application of significant amounts of fertilizers can be avoided, considering the inputs of 449 and 277 kg ha-1year-1.

1-23

Authors: Lucivânia Izidoro da Silva ; Milton César Costa Campos ; Wildson Benedito Mendes Brito* ; José Maurício da Cunha ; Alan Ferreira Leite de Lima; Luís Antônio Coutrim dos Santos; Abdul Luís Hassane

“Erodibility” is a characteristic of the soil that represents the susceptibility with which its particles from the most superficial layer are taken and transported to lower places by erosive agents, causing environmental and economic damages. This work estimated soil erodibility in pastures and forest areas in the municipality of Porto Velho-Rondônia. In the field, three areas with different types of vegetation were selected, one with brachiaria, another with mombaça grass, and a third in native forest. In areas with pastures, a sampling mesh of equal sizes was outlined (90 m x 60 m), and in the forested area an approximate sampling mesh (90 m x 50 m), with a regular spacing of 10 m between the samples points for both areas. The sampling was done at the crossing points of the mesh at a depth of 0.0-0.2 m, composing 70 sample points in the areas with pastures and 60 sample points in the forest area, totaling 200 samples. Then, laboratory analyzes were carried out to determine the texture followed by the fractionation of the sand, and the organic carbon followed by the estimate of the organic matter of the soil. The erodibility factors were calculated using indirect prediction models, and then, univariate, geostatistical and multivariate techniques were applied. The pastures’ environments differed from the forest environment. However, the mombaça grass area functions as an intermediate environment between the forest and the brachiaria, being closer to the forest environment.

1-14

Authors: Camila Bermond Ruezzene ; Renato Billia de Miranda; Talyson de Melo Bolleli; Frederico Fábio Mauad

The study of the hydric regime of rainfall helps in management analysis and decision-making in hydrographic basins, but a fundamental condition is the need for continuous time series of data. Therefore, this study compared gap filling methods in precipitation data and validated them using robust statistical techniques. Precipitation data from the municipality of Itirapina, which has four monitoring stations, were used. Four gap filling techniques were used, namely: normal ratio method, inverse distance weighting, multiple regression and artificial neural networks, in the period from 1979 to 1989. For validation and performance evaluation, the coefficient of determination (R²), mean absolute error (MAE), mean squared error (RMSE), Nash-Sutcliffe coefficient (Nash), agreement index (D), confidence index were used (C) and through non-parametric techniques with Mann-Witney and Kruskal-Wallis test. Excellent performances of real data were verified in comparison with estimated data, with values above 0.8 of the coefficient of determination (R²) and of Nash. Kruskal-Wallis and Mann-Whitney tests were not significant in Stations C1 and C2, demonstrating that there is a difference between real and estimated data and between the proposed methods. It was concluded that the multiple regression and neural network methods showed the best performance. From this study, efficient tools were found to fill the gap, thus promoting better management and operation of water resources.

1-16

Authors: Wellinson Maximin de Souza Severino; Erick Silva dos Santos; Helenilza Ferreira Albuquerque-Cunha

This study assessed the direct impacts of Cachoeira Caldeirão Hydropower Plant (before and during its construction) on the eating habits (fish and wild meat consumption) of the residents in Porto Grande City, Amapá State, Brazil. The study was conducted in 2015, based on a questionnaire for data collection (Sample size = 53) and on comparative analysis for significance (Wilcoxon test, p < 0.05) and correlation (Pearson’s test) assessment. Results suggested significant changes in families’ eating habits. The Wilcoxon test detected three significant variables (p < 0.05): family income, number of species (fish and wild meat consumption) and rate of wild meat consumption per family. Both the Wilcoxon and the Pearson’s correlation tests confirmed two variables (p < 0.05 and r > 0.7): family income versus wild meat consumption before (p value = 0.045; r = - 0.75) and family income versus fish consumption during (p value = 0.0029; r = - 0.83) hydropower plant construction. It can be inferred that the decrease in family fish consumption may be related to changes in the families' eating habits. Changes in diet may have led families to a growing consumption of industrialized and/or ultra-processed foods, very common in geographically isolated Amazon riverside regions with limited access to electricity. Furthermore, families were forced to adapt to a new reality due to environmental changes in their territories.

1-12

Authors: André de Moura Andrade; Rui da Silva Andrade; Erich Collicchio

Brazilian soybean has undergone considerable economic growth. Its production depends on the demand for some inputs. One of these inputs is the soil water supply, which can be made artificially or obtained by natural rainfall. Knowledge of available water capacity (AWC), which depends on total water availability (TWA), is poorly accessible and difficult to measure in the field. This study aimed to map the AWC of the state of Tocantins, based on pedotransfer functions (PTFs), to evaluate the water availability of the soils of the microregions of that state. We used the Arya and Paris model, aided by a computer program, Qualisolo, made by Embrapa Instrumentação. One hundred fifty-seven tropical soil samples were extracted from the Embrapa Solos portal. Preliminarily, the soil water retention curve (SWRC) was obtained and, subsequently, the TWA and AWC for this oilseed were estimated. Multiple linear regressions show the correlation between TWA and clay (CL), Silt (ST) and total sand (TS) contents. The correlation established was TWA = 3.2993 – 0.0028TS – 0.0034CL. This main conclusion reflects a fruitful AWC for decision-making by the soybean agribusiness and exposes the regional weaknesses for this crop under a rainfed regime in some regions of Tocantins. We could observe that, in terms of water availability, agribusiness is a potential threat to the environment protection area (APA) of the Ilha do Bananal/Cantão, Formoso River microregion.

1-13

Authors: Lesly Aguilar Boleji; María Custodio-Villanueva; Fernán Cosme Chanamé Zapata; Walter Javier Cuadrado Campó; Richard Pavel Peñaloza Fernández

Bioconcentration and bioaccumulation levels of lead, zinc, iron and arsenic in Scirpus californicus of the Paca and Tragadero Lagoons, Jauja, Peru, were evaluated. Water, sediment and Scirpus californicus samples were collected from each lagoon, which were transported to the laboratory for the analytical determination of lead, iron, zinc and arsenic, which was performed by atomic absorption spectrophotometry based on the methodology recommended by FAO. The results obtained reveal the current status of the quality of the aquatic environment of natural wetlands in the central region of Peru in terms of heavy metals and arsenic, which provide an important source of water for the populations of large cities in the central region of Peru. The presence of heavy metals and arsenic with great impact on the quality of these water bodies may be due to the pressure exerted by anthropogenic activities such as mining, agriculture, industrial and domestic wastewater. The sediments of Paca and Tragadero Lagoons showed high concentrations of Fe, exceeding international standards. Aquatic vegetation represented by Scirpus californicus in both lagoons bio accumulated mainly Zn, without exceeding international standards.

1-16

Authors: Jaíza Ribeiro Mota e Silva; Luiz Fernando Coutinho de Oliveira ; Camila Silva Franco; Juliano Elvis de Oliveira; Bárbara Belchior Silvério

This study investigated the adsorption capacity of the elements Chromium (Cr), Manganese (Mn) and Zinc (Zn) to marine algae Lithothamnium calcareum by means of adsorption kinetics and batch adsorption tests, with a view to the development of a simple technique for the treatment of effluents that have a high concentration of metal ions. The algae was sieved, washed and subjected to treatment. In the adsorption kinetics, 0.2 g of algae was weighed, an amount transferred to 125 mL Erlenmeyer flasks, to which was added 15 mL of solution with a concentration of 5 mg L-1 of the metal ion. The flasks were stirred at 60 rpm for 240 minutes. In batch adsorption, 0.2 g of algae was weighed, amount transferred to 125 mL Erlenmeyer flasks, to which was added 15 mL of solution with concentrations of 5, 10, 20, 50, 100, 250 e 500 mg L-1 of the metal ion. The flasks were stirred at 60 rpm for 24 hours. In the two tests, the supernatant solutions collected were centrifuged at 2000 rpm for 5 minutes and the equilibrium concentrations of metal ions were determined by atomic absorption spectrometry. It was found that, in 240 minutes of contact, the Lithothamnium calcareum removed 15.5% of Cr, 33.0% of Mn and 8.0% of Zn in solution; and that in 24 hours of contact, at a concentration of 5 mg L-1, it removed 0.4% of Cr, 52.5% of Mn and 92.6% of Zn; and, at a concentration of 500 mg L-1, it removed 20.0% of Cr, 22.6% of Mn and 40.8% of Zn. The results showed that the Lithothamnium calcareum submitted to thermochemical treatment presented potential for use in the adsorption of Cr, Mn and Zn.

1-11

Authors: Flavia Manente da Silva; Fábio Orssatto; Eduardo Eyng; Laercio Mantovani Frare; Ilton José Baraldi ; Leandro Fleck

The demand for food production brings with it the increase of effluent generation, which represents a great problem for slaughterhouses, since effluents contain higher organic load, requiring adequate treatment to decrease environmental impacts. This study examines an alternative to solve this problem: the application of electrocoagulation in the treatment of anaerobic slaughterhouse and packing plant effluents, as this promising technique is both compact and robust. The removal of color, COD and turbidity was analyzed, and the operational cost was calculated. To optimize the process, the CCRD (central composite rotatable design) methodology was used with two independent variables: electric current density and electrolysis time, obtaining a complete factorial of 2² with 4 axial points and 4 repetitions at the central point. The most expressive removals were: 87%, 80% and 76% for color, COD and turbidity, respectively, the lower operational cost obtained was 0.12 US$.m-3. The statistical analysis allowed obtaining valid mathematical models for color removal and cost and, through the analysis of desirability, it was found that for current density of 8 mA.cm-2 and time of 20 minutes it is possible to maximize color removal (84%) and minimize the cost (0.21 US$.m-3).

1-11

Authors: Matheus Rodrigo Machado; David José Miquelluti ; Mari Lucia Campos

Arsenic (As) is one of the most harmful chemical elements known to man and to the environment, mainly due its high toxicity and wide distribution; the content of this element within the soils is a genuine concern, thus making it paramount to know its natural contents in a regional context. The present study aimed to determine the natural Arsenic content in the A horizon of 31 soil profiles from the state of Santa Catarina, Brazil, which is useful in determining reference values, monitoring, remediation of contaminated areas, legal regulation and Brazilian laws. Soil samples were prepared following the USPEA 3051A SW-846 method and were previously chemically reduced from As(V) to AS(III) by using the BCR method. The determination was performed in an Inductively Coupled Plasma - Optical Emission Spectrometry - Hydride Generation (ICP-OES-HG at cold vapor). Results obtained from the soil groups reveal the materials of basaltic origins as the ones with more As content while those of sediment origins had lesser content. Evaluated soil profiles fit into the following descending order regarding their As content: Latossolos, according to EMBRAPA (Oxisols according to Soil Taxonomy) > Nitossolo (Ultisols, Oxisols (Kandic), Alfisols) > Chernossolos (---) = Cambissolo (Inceptisols) = Argissolo (Ultisols) > Neossolos (Entisols).

1-10

Authors: Bessie Evelyn Oliva-Hernández; Francis Mariel Santos-Ruiz ; Manuel Alejandro Muñoz-Wug ; Juan Francisco Pérez-Sabino

Microplastics are plastic particles smaller than 5 mm found in the environment, which can cause health problems for aquatic organisms and humans, being classified as emerging pollutants. In Guatemala, Lake Amatitlán is one of the most polluted lakes as it receives discharges of wastewater, treated and untreated, as well as other waste from Guatemala City and other major urban populations. In a recent study, microplastics were found in sediments in Lake Amatitlán, so it was necessary to determine whether the lake's fish are affected by these pollutants, which can be harmful to their health. This research aimed to determine the microplastics in fish from Lake Amatitlán, for which 65 specimens of Nile tilapia (Oreochromis niloticus) were collected in October and December 2020, and January 2021. The collected fish were dissected in the laboratory, where the number and type of microplastics were analyzed in the digestive tract, after their separation by digestion and filtration. Lines or fibers were the most common type of microplastics, found in 63 specimens (96.9% of the analyzed specimens), ranging from 0 to 27 lines/fibers per individual. The frequency of other types of microplastics found were 0-3 fragments/individual, 0-2 films/individual, and 0-4 foams/individual, while microspheres were not found in any specimen. The presence of microplastics in tilapia from Lake Amatitlán is an indicator of contamination in the lake by pollutants that could affect the trophic network and represents a risk for the fish consumers, requiring the attention of environmental and health authorities.

1-20

Authors: Lucilene Finoto Viana; Bruno do Amaral Crispim; Juliana Caroline Vivian Sposito; Milena Perez de Melo; Luiza Flávia Veiga Francisco; Valter Aragão do Nascimento; Alexeia Barufatti

This study assessed the concentrations of metals in the Dourados and Brilhante Rivers, investigated the influence of landscape features surrounding these rivers on water quality, and evaluated the risks associated with metal contamination for aquatic biota and human health. Sampling was conducted at eighteen sites distributed along the rivers in June 2016. The concentrations of metals (Cu, Zn, Mn, Fe, Cr, Al and Co) in the water were analyzed by inductively coupled plasma optical emission spectroscopy. All the samples possessed Fe concentrations above the threshold value for aquatic biota (0.3 mg L-1). Moreover, land use and land cover assessment of the study area revealed extensive agriculture activity, particularly in areas surrounding the Dourados River headwaters. Fe bioavailability for both rivers indicated risks for aquatic biota and human health. Overall, the elevated Fe content in these rivers was attributed to anthropogenic activity in the vicinity of these water bodies and the soil characteristics of the area. Considering the importance of river basins, it is necessary to implement public policies for their conservation, especially those related to the cultivation of forests of native species and sustainable agricultural practices, in addition to improving the effluent treatment infrastructure, which is essential to minimize the adverse effects of contamination by chemical elements in water bodies.