Navegando por Autor "Chagas, Igor Aparecido Santana das"
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Item Aqueous chlorination of herbicide metribuzin : Identification and elucidation of new disinfection by-products, degradation pathway and toxicity evaluation.(2021) Barros, André Luis Corrêa de; Rodrigues, Daniel Aparecido da Silva; Cunha, Camila Cristina Rodrigues Ferreira da; Chagas, Igor Aparecido Santana das; Espirito Santo, Daiana Rocha do; Silva, Silvana de Queiroz; Afonso, Robson José de Cássia FrancoA widely used herbicide, metribuzin, was evaluated for degradation, mineralization and disinfection byproducts (DBPs) formation during aqueous chlorination. In addition, to assess the toxicity effects of chlorination on metribuzin solution the following tests were performed: acute toxicity using Artemia salina nauplii; cell viability using MTT assay; estrogenicity using a re-engineered Bioluminescent Yeast Estrogen Screen (BLYES) and a constitutively bioluminescent strain (BLYR); mutagenicity and developmental toxicity using Q(SAR) methodology. Metribuzin at 10 mg·L−1 was degraded by chlorination, achieving 93% of removal at 30 min of reaction. TOC analysis showed that the herbicide does not suffer complete mineralization, even after 24 h of contact with free chlorine. Seventeen DBPs were detected and their structural formulae were elucidated by high resolution mass spectrometry. Toxicity effects for chlorinated solutions increased when compared to the unreacted metribuzin solution. DBPs were more toxic to Artemia salina nauplii, increasing around 20% on nauplii mortality. It was also observed high estrogenicity to human receptors in BLYES assays and mutagenic and developmental toxicant effects to animals and humans in Q(SAR) methodology, suggesting that DBPs are potentially more toxic than the precursor metribuzin. Metribuzin solutions at 10 mg·L−1 showed equivalent 17-β-estradiol values ranged from 0.061 to 6.71 μg·L−1 after to be chlorinated at different reaction times.Item Household-based biodigesters promote reduction of enteric virus and bacteria in vulnerable and poverty rural area.(2019) Lanna, Maria Célia da Silva; Viancelli, Aline; Michelon, William; Carvalho, Sergio Vinícius Castro; Reis, Deyse Almeida dos; Salles, Luiz Antonio Fernandez de; Sant’Anna, Iago Hashimoto; Resende, Letícia Teresinha; Ferreira, Clovis de Souza; Chagas, Igor Aparecido Santana das; Hernandez, Marta; Treichel, Helen; Rodríguez Lázaro, David; Fongaro, GislaineThe present study evaluated the river water quality improvement by implementation of household-based biodigesters in vulnerability and poverty rural area, in Minas Gerais State-Brazil. For that, 78 household-based biodigesters were installed for domestic wastewater treatment. Wastewater was collected before and after treatment and the physicochemical parameters and pathogens removal (human adenovirus (HAdV), hepatitis A (HAV) virus, Salmonella sp. and Escherichia coli) were evaluated; Additionally, river water was sampled before and after the household-based biodigesters implementation, to verify the contamination reduction and the positive impact of domestic wastewater treatment on waterborne pathogen reduction, considering HAdV, HAV, Salmonella sp. and E. coli quantification. The applicability in real-scale of decentralized treatment systems using household-based biodigesters promoted reduction of 90, 99, 99.99 and 99.999% from HAV, Salmonella sp., E. coli and HAdV from domestic wastewater, respectively; The river water quality improvement before the wastewater treatment application was highlight in the present study, considering that the reduction of waterborne pathogens in this water in 90, 99.99 and 99.999% of E. coli, HAV and HAdV, respectively (Salmonella sp. was not detected in river water). In general, this is an important study for encouraging the decentralized sanitation in vulnerable and poverty area, as well in rural sites, considering the positive impact of this implementation on public health.Item Restrição do uso das águas da bacia hidrográfica do rio Matipó devido à contaminação microbiológica.(2019) Reis, Deyse Almeida dos; Nascimento, Laura Pereira do; Marques, Lílian de Souza; Oliveira, Edilson Gonçalves de; Ferreira, Clovis de Souza; Chagas, Igor Aparecido Santana das; Roeser, Hubert Mathias Peter; Santiago, Aníbal da FonsecaO presente estudo foi realizado na bacia hidrográfica do Rio Matipó, um afluente do Rio Doce, em Minas Gerais – Brasil. O principal objetivo foi avaliar a contaminação microbiológica das águas da bacia devido à influência da atividade humana. Para tal, foram realizadas amostragens de água em 25 estações de monitoramento situadas ao longo do curso hídrico em períodos sazonais distintos. Essas amostragens possibilitaram mensurar variáveis químicas e microbiológicas das águas. A análise dos dados obtidos permitiu observar a limitação dos usos da água da bacia hidrográfica pelo fato de estar contaminada com microrganismos, alguns potencialmente patogênicos. Os impactos ambientais verificados na bacia hidrográfica, como criação de animais nas margens e, principalmente, lançamento de esgoto sanitário sem tratamento, foram os principais fatores que interferiram na limitação dos usos da água para balneabilidade e para o abastecimento público.Item Restrição do uso das águas da bacia hidrográfica do rio Matipó devido à contaminação microbiológica.(2020) Reis, Deyse Almeida dos; Nascimento, Laura Pereira do; Marques, Lilian de Souza; Oliveira, Edilson Gonçalves de; Ferreira, Clovis de Souza; Chagas, Igor Aparecido Santana das; Roeser, Hubert Mathias Peter; Santiago, Aníbal da FonsecaO presente estudo foi realizado na bacia hidrográfica do Rio Matipó, um afluente do Rio Doce, em Minas Gerais – Brasil. O principal objetivo foi avaliar a contaminação microbiológica das águas da bacia devido à influência da atividade humana. Para tal, foram realizadas amostragens de água em 25 estações de monitoramento situadas ao longo do curso hídrico em períodos sazonais distintos. Essas amostragens possibilitaram mensurar variáveis químicas e microbiológicas das águas. A análise dos dados obtidos permitiu observar a limitação dos usos da água da bacia hidrográfica pelo fato de estar contaminada com microrganismos, alguns potencialmente patogênicos. Os impactos ambientais verificados na bacia hidrográfica, como criação de animais nas margens e, principalmente, lançamento de esgoto sanitário sem tratamento, foram os principais fatores que interferiram na limitação dos usos da água para balneabilidade e para o abastecimento público.Item Successive pandemic waves with different virulent strains and the effects of vaccination for SARS-CoV-2.(2022) Silva, Alcides Castro e; Bernardes, Américo Tristão; Barbosa, Eduardo Augusto Gonçalves; Chagas, Igor Aparecido Santana das; Cruz, Wesley Francisco Dáttilo da; Reis, Alexandre Barbosa; Ribeiro, Sérvio PontesOne hundred years after the flu pandemic of 1918, the world faces an outbreak of a new severe acute respiratory syndrome, caused by a novel coronavirus. With a high transmissibility, the pandemic has spread worldwide, creating a scenario of devastation in many countries. By the middle of 2021, about 3% of the world population had been infected and more than 4 million people had died. Different from the H1N1 pandemic, which had a deadly wave and ceased, the new disease is maintained by successive waves, mainly produced by new virus variants and the small number of vaccinated people. In the present work, we create a version of the SIR model using the spatial localization of persons, their movements, and considering social isolation probabilities. We discuss the effects of virus variants, and the role of vaccination rate in the pandemic dynamics. We show that, unless a global vaccination is implemented, we will have continuous waves of infections.Item Successive pandemic waves with different virulent strains and the effects of vaccination for SARS-CoV-2.(2022) Silva, Alcides Castro e; Bernardes, Américo Tristão; Barbosa, Eduardo Augusto Gonçalves; Chagas, Igor Aparecido Santana das; Dáttilo, Wesley; Reis, Alexandre Barbosa; Ribeiro, Sérvio PontesOne hundred years after the flu pandemic of 1918, the world faces an outbreak of a new severe acute respiratory syndrome, caused by a novel coronavirus. With a high transmissibility, the pandemic has spread worldwide, creating a scenario of devastation in many countries. By the middle of 2021, about 3% of the world population had been infected and more than 4 million people had died. Different from the H1N1 pandemic, which had a deadly wave and ceased, the new disease is maintained by successive waves, mainly produced by new virus variants and the small number of vaccinated people. In the present work, we create a version of the SIR model using the spatial localization of persons, their movements, and considering social isolation probabilities. We discuss the effects of virus variants, and the role of vaccination rate in the pandemic dynamics. We show that, unless a global vaccination is implemented, we will have continuous waves of infections.Item Worldwide COVID-19 spreading explained : traveling numbers as a primary driver for the pandemic.(2020) Ribeiro, Sérvio Pontes; Cruz, Wesley Francisco Dáttilo da; Barbosa, David Soeiro; Vital, Wendel Coura; Chagas, Igor Aparecido Santana das; Silva, Alcides Volpato Carneiro de Castro e; Morais, Maria Helena Franco; Góes Neto, Aristóteles; Azevedo, Vasco Ariston de Carvalho; Fernandes, Geraldo Wilson Afonso; Reis, Alexandre BarbosaThe spread of SARS-CoV-2 and the distribution of cases worldwide followed no clear biogeographic, climatic, or cultural trend. Conversely, the internationally busiest cities in all countries tended to be the hardest hit, suggesting a basic, mathematically neutral pattern of the new coronavirus early dissemination. We tested whether the number of flight passengers per time and the number of international frontiers could explain the number of cases of COVID-19 worldwide by a stepwise regression. Analysis were taken by 22 May 2020, a period when one would claim that early patterns of the pandemic establishment were still detectable, despite of community transmission in various places. The number of passengers arriving in a country and the number of international borders explained significantly 49% of the variance in the distribution of the number of cases of COVID-19, and number of passengers explained significantly 14.2% of data variance for cases per million inhabitants. Ecological neutral theory may explain a considerable part of the early distribution of SARS-CoV-2 and should be taken into consideration to define preventive international actions before a next pandemic.