Revista Ambiente & Água - An Interdisciplinary Journal of Applied Science

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.