RCAAP Repository

Abstract Coagulants can be extracted from vegetal material and applied in the treatment of wastewater. These coagulants are derived from seeds, leaves, bark, roots and fruits. This study focuses on the use of the mucilaginous extract ofStenocereus griseus(known as Cardón Guajiro) for removal of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total solids, turbidity and color in domestic wastewater from a pumping station in the city of Cartagena (Colombia). The optimal dose ofS. griseusextract was determined by a pitcher test employing an E&Q F6-300 digital flocculator. All physicochemical tests were carried out following the specifications of the standard methods for wastewater (APHA). When 1400 mgL-1 of natural coagulants were used in the sewage treatment, the turbidity obtained was 29.57 TNU, representing removal of 67.24%, considering the initial turbidity. This parameter decreases until 68.61 PCU, for a 72.12% removal at the same coagulant dosage regarding the color. It must be noted that significant statistical differences were found between all tested doses of the coagulant. The mucilaginous extract of S. griseus exhibited useful properties in the primary treatment of domestic wastewater.

Abstract Fires such as those that occurred in 2019 in the Amazon are examples of the intensification of these events in recent years and contradict the claim that forest fires only reach great proportions in years of extreme drought. This is a worrying scenario, as the Amazon Rainforest plays an important role in regional and global climate regulation. This study therefore sought to identify the methodologies used to describe and predict fire events in the Brazilian Amazon. For this, a systematic literature review was carried out in the open access databases Scientific Electronic Library Online (SciELO) and Directory of Open Access Journals (DOAJ) using the descriptors “fire risk” and “Amazon”, and their variants in the Portuguese language and the logical operator “AND” in the search. From the resulting search materia we identified the use of predictive models based on projections for climate change developed by the Intergovernmental Panel on Climate Change (IPCC), which indicate a substantial increase in the probability of fires. Another technique used is the crossing of heat foci data with the forms of land use, evidencing the areas that burn the most and when, as well as the most susceptible areas. There were also studies analyzing the performance of fire risk indexes, demonstrating those that could be used after adaptations to local characteristics. These results allow an understanding of the behavior of fire in the Amazon, since they provide a broad view of how studies on fires have been conducted and what techniques have been used.

Abstract Water erosion is one of the main forms of soil degradation, causing economic, environmental, and social damage. This study evaluated the effects of different formation stages of gullies (initial - IG; juvenile- JG; mature - MG; and senile - SG) on the chemical, organic carbon and microbiological attributes of soil, using a secondary forest (SF) and two areas of pasture as references in the “Mar de Morros” environment of the Brazilian Atlantic Forest biome. Soil samples (depth 0-0.05 m) were collected at the end of the rainy and dry seasons. Gullies in different stages of formation promote a decrease in soil fertility and modification of microbiological attributes, particularly when compared with secondary forest areas. Reductions of over 60% in total organic carbon (TOC), oxidizable organic carbon (POXC), FDA activity, β-glycosidase, acid phosphatase, C and N from microbial biomass, basal soil respiration (BSR) and glomalin-related soil protein (GRSP) were observed in gullies in early (IG) and intermediate (JG and MG) stages when compared to SF. It was found that the effect of erosion on soil chemical and microbiological attributes is more intense in gullies in the initial and intermediate stages compared with those in the senile stage (SG). Using multivariate PCA, the microbiological and chemical attributes of the soil are discriminated between gullies with distinct formation stages. Chemical attributes, TOC, POXC, FDA activity, β-glycosidase, acid phosphatase, MBC and MBN, BSR, and GRSP are good indicators for evaluating the process of erosion stabilization in gullies.

Abstract This article presents an overview of the application of soil bioengineering techniques, also modeled as natural engineering, in the state of Sergipe, northeastern Brazil, showing the importance of integrating living and inert elements to protect river banks from erosion. The employed techniques are different, ranging from the characterization of susceptibility to erosion to the use of biotechniques, considering knowledge in the areas of agronomic engineering, forestry engineering, civil engineering, biology, pedology, geology, geomorphology and geotechnics. It is an approach that uses techniques and methodologies in a multidisciplinary way, seeking to maximize synergies (for example, natural engineering techniques to combine inert materials in ways that help plants to develop increasingly efficient systems). This approach also considers maintenance-cost optimization in the conduction of the works, using different materials, differing from traditional engineering, which uses predominantly inert materials. The research work carried out in different locations sought the availability of local materials such as rocks, geotextiles made from fibers from the native flora or even available on the market, in addition to the use of native species to recovery of the banks or slopes, according to the ecological conditions of the northeastern Brazil. Size and technological and ecological reach were also considered, in addition to different biotechnical aesthetic objectives adapted to different situations.

Abstract At the beginning of 2020, about 9 million inhabitants of the Metropolitan Region of Rio de Janeiro, dependent on the Guandu Basin, experienced a water-supply crisis when their water tasted badly and gave off an odor. This work presents the results of analyses of the sanitary quality of raw water in this system at two different times during the water crisis, with respect to the presence of cyanobacteria found using metagenomic studies, and cyanotoxins, microcystin (MC) and saxitoxin (SXT) quantified by ELISA. Analyses of raw water quality parameters were carried out through the determination of total coliforms and Escherichia coli levels and some physical-chemical parameters. The raw water collected in both periods presented levels of Escherichia coli levels above the maximum allowed values (MAV) described in Resolution 357/2000 of the National Environmental Agency, as well as the levels of MC in a filter sample. The physical-chemical parameters analyzed and the SXT levels were in accordance with this resolution. The most abundant cyanobacterial genus in the critical period was Planktothricoides sp. Therefore, it is necessary to implement basic sanitation in cities upstream from the point of capture of raw water from this source, so that events similar to those that occurred in the 2020 water crisis do not recur.

Abstract The Soil Conservation Service Curve Number Model is a conceptual model intended for estimating effective rainfall (ER). This model is grounded in a parameter - referred to as Curve Number (CN), which is determined from information on the characteristics of the watershed. The Standard Method (M1) for determining the CN is based on soil and land-use tables; however, some authors have proposed alternative methodologies for defining the CN value from monitored rainfall-runoff events, such as those described by Hawkins (1993) (M2), Soulis and Valiantzas (2012) (M3), and Soulis and Valiantzas (2013) (M4). The objective of this study was to evaluate the impact of using these methods for determination of the CN parameter on the estimation of ER, taking as reference forty rainfall-runoff events monitored between 2015 and 2018 in the Cadeia River Watershed, which has characteristics of the Pampa biome. The different methods assessed for definition of the CN parameter resulted in contrasting performances with respect to the estimation of ER for CRW, as the following findings: i) M1 gave ER values with little reliability, mainly due to the classification of antecedent moisture content classes; ii) M3 provided the best results in determining ER, followed by M2; and iii) the ER values estimated according to M4 differed from those observed, mainly for events with lower rainfall depths.

Abstract This study investigated the use of a combined formula of artificial feed and fresh marine algae Gracilaria sp in a submerged cage culture system and its effect on Haliotis squamata relative growth and survival rates. The experiment was performed in Lae-Lae Island, Makassar from May to October 2016. The sample Abalone juvenile larvae were 1.5 cm in size and stocked at a density of 30 pcs/cage. The cage size was 30 cm x 15 cm x 7 cm and equipped with a 2-inch Paralone pipe. This experiment employed a completely random design (CRD) with 3 treatments and 3 replicates. The applied treatment included the combination of artificial feed and fresh marine algae Gracilaria sp. Each treatment included: A. 25% artificial feed + 75% fresh marine algae, B. 50% artificial feed + 50% fresh marine algae, C. 75% artificial feed + 25% fresh marine algae, and was given at the proportion of 20% of the abalone's weight. The results of the study indicated that the use of a combined artificial feed with fresh marine algae (Gracilaria sp.) had no significant effect on relative growth and survival rates of Haliotis squamata. Although feed treatment did not significantly affect the relative growth and survival rate, descriptively, treatment A contributed to the most optimal relative growth and the survival rate compared to treatments B and C.

Abstract This study assessed the impact of climate change on monthly streamflow in the Verde River Basin, located in the Grande River Basin headwater. For this purpose, the SWAT and VIC hydrological models were used to simulate the monthly streamflow under RCP4.5 and RCP8.5 scenarios, obtained by Regional Climate Models Eta-HadGEM2-ES, Eta-CanESM2 and Eta-MIROC5 in the baseline period (1961-2005) and three time-slice (2011-2040, 2041-2070, and 2071-2099) inputs. At the end of the century, the Eta-HadGEM2-ES showed larger decrease of precipitation in both radiative scenarios, with an annual reduction of 17.4 (RCP4.5) and 32.3% (RCP8.5), while the Eta-CanESM2 indicated major warming, with an annual increase of 4.7 and 10.2°C under RCP4.5 and RCP8.5, respectively. As well as precipitation changes, the Eta-HadGEM2-ES also showed greater impacts on streamflow under RCP4.5 for the first time-slice (2011-2040), with an annual decrease of 58.0% for both hydrological models, and for the RCP8.5 scenario by the end the century (2071-2099), with an annual reduction of 54.0 (VIC model) and 56.8% (SWAT model). Regarding monthly streamflow, the Eta-HadGEM2-ES and Eta-CanESM2 inputs indicated decrease under the RCP8.5 scenario by the end the century, varying from 7.2 to 66.3 % (VIC model) and 37.0 to 64.7% (SWAT model). In general, Eta-MIROC5 presented the opposite in terms of direction in the simulations with both hydrological models at the end of the century. Combined effects of climate models, hydrological model structures and scenarios of climate change should be considered in assessments of uncertainties of climate change impacts.

Abstract Environmental and operational performance of a full-scale small and decentralized construction and demolition waste (C&DW) recycling unit (SDRU) were evaluated. The SDRU was defined as having a production capacity of up to 5 m3 per hour, occupying up to 100 m2. The operational and environmental performance indicators of the SDRU were obtained from the literature and validated by expert judgment. Subsequently, the values of these indicators were obtained from a real-scale SDRU in Bahia state, Brazil. The results showed that the SDRU presented lower levels of noise emission, very small water and energy consumption, and inhalable-particle concentration values lower than the requirements of Brazilian environmental legislation. It was observed that 90% of the C&DW in the storage area had recycling potential. The characteristics of the fine recycled aggregate make it suitable for use in road or sidewalk paving, and the coarse recycled aggregate is suitable for use in concrete without structural function. A Life Cycle Assessment (LCA) of the SDRU was also applied and it was concluded that the use of the recycled aggregate for manufacturing concrete without structural function reduced the environmental impact in all the categories considered, compared with the impact of natural sand and gravel extraction from nature. It was possible to conclude that the implementation of the SRDU in developing countries can provide an effective step towards reducing environmental impacts from the construction sector.

Abstract Floods are responsible for a high number of human and material losses every year. Monitoring of river levels is usually performed with radar and pre-configured sensors. However, a major flood can occur quickly. This justifies the implementation of a real-time monitoring system. This work presents a hardware and software platform that uses Internet of Things (IoTFlood) to generate flood alerts to agencies responsible for monitoring by sending automatic messages about the situation of rivers. Research design involved laboratory and field scenarios, simulating floods using mockups, and later tested on the Mundaú River, state of Alagoas, Brazil, where flooding episodes have already occurred. As a result, a low-cost, modular and scalable IoT platform was achieved, where sensor data can be accessed through a web interface or smartphone, without the need for existing infrastructure at the site where the IOTFlood solution was installed using affordable hardware, open source software and free online services for the viewing of collected data.

Abstract The reduction of tropical forests has generated a loss of ecosystem services across the globe. In Brazil, essential biomes related to water provision (such as the Atlantic Forest and Savanna) have been degraded, compromising water-ecosystem services. Payment for water-ecosystem services (water PES) has been implemented as a tool to stimulate changes in the use and management of these areas. Many water PES projects have emerged in Brazil using forest restoration, aiming to improve water ecosystem services. In this context, this study identified the types of monitoring carried out in Brazilian water PES projects, to include their main characteristics and gaps. Five Brazilian projects were selected for analysis as case studies. Interviews were then conducted with stakeholders to get current data on their monitoring practices. The data from the literature review, case study approach, and interviews were analyzed from the perspective of monitoring guides recommendations. Different aspects were analyzed, such as objectives, institutional arrangements, type of monitoring, indicators, and frequency of monitoring. The study indicates that there is a lack of standardized methods, making it difficult to specify the results of the implemented actions. The central gap is related to benefit monitoring. It is necessary to establish a holistic monitoring system, dealing with the ecosystem as a complex socio-ecological system. Some perspectives to solve the problems were proposed. The results of this work may help not only improve the current and future PES schemes in Brazil but also in other countries, especially developing ones, where vulnerable populations depend upon them.

Abstract Emerging contaminants such as 17α-ethynylestradiol (EE2) can be discharged from sewage systems and contaminate water supplies. Paranoá Lake is a strategic water reservoir in Brasília (Brazil) that receives treated sewage from sewage treatment plants (STPs) and has recently become a water supply. This study monitored EE2 residues in different matrices from Paranoá Lake watershed using the ELISA method. This monitoring was performed together with the local environmental agency in two periods. EE2 was detected in all sewage samples showing that this residue is continually being discharged into the lake. However, EE2 was found in only one freshwater sample (0.07 ng L-1), which is below the predicted no-effect concentration considered as a risk for aquatic animals. EE2 was not detected in treated water. Nevertheless, the increased use of freshwater as a water supply signals the need for continuous EE2 monitoring in the lake.

Abstract The Local Production Arrangement, located in the Pernambuco’s Agreste state, has been significantly developing the region's economy. Despite its importance, industrial activity has caused relevant environmental concerns regarding the disposal of textile effluents, especially from industrial laundries. This waste is made up of many chemicals, and among them are various types of heavy metals. The evaluation of the sorption behavior of contaminant transport mechanisms such as heavy metals is essential to assess the risk of contamination of alluvial aquifers. This study evaluated the sorption of heavy metals (Cu and Cd) in an alluvial sediment deposit in the Capibaribe River. Kinetics and isotherm experiments allowed the analyses of Cu and Cd sorption. Kinetics sorption showed an equilibrium tendency after 16 h for Cu and 18 h for Cd and was better described by a pseudo-second order model. The isotherm data were adjusted to the Linear, Freundlich and Langmuir models. Both linear and Freundlich models satisfactorily described sorption isotherms for the two pollutants. The metals in the study represent a risk of contamination of the groundwater of alluvial aquifers, mainly due to physicochemical attributes of the soil, such as high sand content (85%), low MO (2.1 g kg-1) and alkaline pH (8.2). The environmental conditions decrease absorption and facilitate metal mobility, greatly increasing the environmental risks inherent in pollutant leaching. Cu showed a higher affinity with the soil studied in all assays performed compared with the results of the tests for Cd.

Abstract The objective of this study was to compare cattle drinking water consumption collected electronically with that of direct human observation using water metres and to analyse whether an automated system compensates due to its greater precision. The study was conducted in the feedlot of Embrapa Pecuaria Sudeste. The reference unit had four pens: two with electronic drinkers and two with water metres. Experiment 1 utilised 52 Nelore steers and Experiment 2 utilised 44 Canchim steers. Nelore fed a conventional diet, the automated system median daily water intake (DWI) was higher than for animals drinking from the water metre, 17.9 L day-1 and 15.6 L day-1. The reverse was observed for animals fed the co-product diet, the automated system median DWI was 18.9 L day-1 and in the water metre pen was 23.0 L day-1. When the Canchim drank from water metres, the median DWI was lower than with the automated system group, 25.9 L day-1 and 27.8 L day-1, respectively. In Experiment 1, there was a statistical difference between the two sets of equipment for both diets. In Experiment 2, the animals were the same breed, had similar weights and were fed the same diet. There was no statistical difference between the equipment in these conditions. The results indicate that the water meter can have the same performance as high technology at a much lower cost. If a more simplified system for measuring water consumption has the same performance as an automated system, this will justify its use with environmental and economic advantages.

Abstract This research developed a Water Quality Index (WQI) for public supply in the Vale do Rio Pardo Region, RS, Brazil (WQI-VRP), from the database of the 13th Regional Health Coordination, totaling 1175 samples. A filtration process resulted in 285 samples with the variables free residual chlorine, turbidity, apparent color, pH, fluoride, total coliforms and Escherichia coli. For water consumption purposes, the Water Quality Index developed by the Sanitation Company of Goiás, Brazil, was used. A multivariate calibration of the weights of importance of the parameters included in the original index was performed, resulting in the WQI-VRP. Comparing the medians of the two indexes, it was found that there were significant differences (p<0.05), qualifying the WQI-VRP as more restrictive. The results indicated that 89.8% of the samples were classified as non-compliant samples by WQI-VRP, while 10.2% were classified as compliant samples. Of the 285 samples analyzed, 72 samples of chlorine, 12 of total coliform, 5 of E. coli, 2 of color, 200 of fluoride and 26 of pH, were below or above the minimum or maximum values required by Brazilian legislation. The pH and fluoride correspond to the critical variables of the study region, as they were the parameters that showed the greatest increases in relative weights when comparing the original index with the calibrated one. These results confirm the use of the WQI-VRP as an efficient tool to assess the quality of drinking water in Brazilian subtropical and temperate lotic systems.

Abstract The aim of this study was to identify the risk of population’s exposure, by different exposure routes, to Zn, Ni, Cu, Cr, and Pb in the soil of a condominium. Six sampling points in three campaigns provided thirty-six soil samples, collected at two depths, one superficial, 0.20 m, and the other underground, between 2.00 and 3.00 m. The results show that the levels of metals in the condominium's soil are generally high. Children cannot withstand the same doses as adults since they are more susceptible and risk greater damage to health. The non-carcinogenic risk based on the hazard quotient (HQ) and the health index (HI) values for each exposure pathway and for each metal were observed to be less than (<) 1. The results showed an immediate carcinogenic risk by chromium ingestion for children. Nevertheless the combined effect for each exposure pathway (TCRI) for adults is close to becoming unacceptable after exposure to Cr by ingestion. The results suggest that contamination by metals is more likely to occur among children than adults at similar exposure levels. Thus, the condominium built on an area contaminated by steel industry waste raises concern, requiring the continuous monitoring of its population.

Abstract Selectivity is a fishing gear characteristic capable of catching fish of a specific size and species from the existing population distribution. Mesh size is one of the important factors that influence gillnets’ selectivity, because different length-classes of fish are caught by them. This report focuses on the selectivity of two mesh sizes of gillnets (8.89 cm and 10.16 cm) on mackerel's catch and constructing a gillnet in Sungailiat waters. Experimental fishing methods and selectivity analysis were used for the fishing gear’s more selective preparation, if the largest fishing ratio's value at the fork length (L) is high and the standard deviation value (S) is closer to 1. It is concluded that to be more selective a largest S (L) value of 0.999267194 at fork length (L=54.95 cm), and with a larger value of S (L) 0.997096071 and with (L=66.55 cm) for mesh Sizes 8.89 cm and 10.16 cm, respectively.

Abstract 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.

Abstract A process-based model was used to simulate a hindcast based on the worst historical water quality condition of a tropical urban reservoir. Paranoá Lake is located in Brasília-DF, Brazil, and went through intense eutrophication in the 70s and 90s, with an important cyanobacterial bloom event in 1978. The parameters of phytoplankton were calibrated, focusing on the group of Chlorophyta (green algae) and Cyanobacteria (blue-green algae) at four depths (1, 10, 15 and 20m). The results indicated that the model was able to reproduce the Cyanobacteria biomass in comparison with the observations (RMSE=22-29.10-3 mgC L-1). On the other hand, the simulated Chlorophyta biomass showed good agreement with the observed data only in the bottom layer (RMSE=29. 10-3 mgC L-1 at 20m). In the hindcast simulation, the model was able to predict a significant increase in cyanobacterial biomass facing a water quality deterioration. In the meantime, the simulated Chlorophyta biomass decreased, which may indicate the phytoplankton group succession in response to the environmental conditions.

Abstract 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.