Subjects -> ENVIRONMENTAL STUDIES (Total: 960 journals)
    - ENVIRONMENTAL STUDIES (853 journals)
    - POLLUTION (31 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (58 journals)
    - WASTE MANAGEMENT (18 journals)

ENVIRONMENTAL STUDIES (853 journals)                  1 2 3 4 5 | Last

Showing 1 - 200 of 378 Journals sorted alphabetically
ACS Chemical Health & Safety     Hybrid Journal   (Followers: 5)
ACS ES&T Engineering     Hybrid Journal   (Followers: 9)
Acta Brasiliensis     Open Access   (Followers: 3)
Acta Ecologica Sinica     Open Access   (Followers: 11)
Acta Environmentalica Universitatis Comenianae     Open Access   (Followers: 1)
Acta Limnologica Brasiliensia     Open Access   (Followers: 4)
Acta Oecologica     Hybrid Journal   (Followers: 12)
Acta Regionalia et Environmentalica     Open Access   (Followers: 1)
Advanced Electronic Materials     Hybrid Journal   (Followers: 7)
Advanced Energy and Sustainability Research     Open Access   (Followers: 8)
Advanced Sustainable Systems     Hybrid Journal   (Followers: 8)
Advances in Ecological Research     Full-text available via subscription   (Followers: 45)
Advances in Environmental Chemistry     Open Access   (Followers: 11)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 21)
Advances in Environmental Technology     Open Access   (Followers: 1)
Advances in Life Science and Technology     Open Access   (Followers: 23)
Advances in Tropical Biodiversity and Environmental Sciences     Open Access   (Followers: 5)
Aeolian Research     Hybrid Journal   (Followers: 6)
African Journal of Environmental Science and Technology     Open Access   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 5)
Agricultural & Environmental Letters     Open Access   (Followers: 3)
Agro-Science     Full-text available via subscription   (Followers: 3)
Agroecological journal     Open Access  
Agronomy for Sustainable Development     Open Access   (Followers: 22)
Agrosystems, Geosciences & Environment     Open Access   (Followers: 7)
Amazon's Research and Environmental Law     Open Access   (Followers: 5)
Ambiência     Open Access  
Ambiens. Revista Iberoamericana Universitaria en Ambiente, Sociedad y Sustentabilidad     Open Access   (Followers: 1)
Ambiente & sociedade     Open Access   (Followers: 3)
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Energy and Environment     Open Access   (Followers: 5)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Environmental Protection     Open Access   (Followers: 9)
American Journal of Environmental Sciences     Open Access   (Followers: 11)
American Naturalist     Full-text available via subscription   (Followers: 85)
Annals of Civil and Environmental Engineering     Open Access   (Followers: 3)
Annals of Environmental Science and Toxicology     Open Access   (Followers: 3)
Annals of GIS     Open Access   (Followers: 30)
Annual Review of Ecology, Evolution, and Systematics     Full-text available via subscription   (Followers: 89)
Annual Review of Environment and Resources     Full-text available via subscription   (Followers: 16)
Annual Review of Pharmacology and Toxicology     Full-text available via subscription   (Followers: 36)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
Applied and Environmental Soil Science     Open Access   (Followers: 20)
Applied Ecology and Environmental Sciences     Open Access   (Followers: 30)
Applied Environmental Education & Communication     Hybrid Journal   (Followers: 19)
Applied Journal of Environmental Engineering Science     Open Access   (Followers: 2)
Aquatic Ecology     Hybrid Journal   (Followers: 39)
Aquatic Toxicology     Hybrid Journal   (Followers: 25)
Arcada : Revista de conservación del patrimonio cultural     Open Access   (Followers: 2)
Architecture, Civil Engineering, Environment     Open Access   (Followers: 4)
Archives des Maladies Professionnelles et de l'Environnement     Full-text available via subscription  
Archives of Environmental and Occupational Health     Hybrid Journal   (Followers: 12)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14)
Archives of Toxicology     Hybrid Journal   (Followers: 20)
Arctic Environmental Research     Open Access   (Followers: 1)
Asian Journal of Environment & Ecology     Open Access   (Followers: 1)
Asian Journal of Rural Development     Open Access   (Followers: 9)
Asian Review of Environmental and Earth Sciences     Open Access   (Followers: 3)
ATBU Journal of Environmental Technology     Open Access   (Followers: 5)
Atmospheric and Climate Sciences     Open Access   (Followers: 35)
Atmospheric Environment     Hybrid Journal   (Followers: 75)
Atmospheric Environment : X     Open Access   (Followers: 3)
Augm Domus : Revista electrónica del Comité de Medio Ambiente de AUGM     Open Access  
Austral Ecology     Hybrid Journal   (Followers: 18)
Australasian Journal of Environmental Management     Hybrid Journal   (Followers: 13)
Australasian Journal of Human Security     Full-text available via subscription   (Followers: 1)
Australian Journal of Environmental Education     Full-text available via subscription   (Followers: 11)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 13)
Basic and Applied Ecology     Hybrid Journal   (Followers: 25)
Behavioral Ecology     Hybrid Journal   (Followers: 60)
Behavioral Ecology and Sociobiology     Hybrid Journal   (Followers: 38)
Biocenosis     Open Access  
Biochar     Hybrid Journal   (Followers: 3)
Biodegradation     Hybrid Journal   (Followers: 2)
Biodiversity     Hybrid Journal   (Followers: 30)
Biofouling: The Journal of Bioadhesion and Biofilm Research     Hybrid Journal   (Followers: 7)
Bioremediation Journal     Hybrid Journal   (Followers: 5)
BioRisk     Open Access   (Followers: 3)
BMC Ecology     Open Access   (Followers: 24)
Boletín Instituto de Derecho Ambiental y de los Recursos Naturales     Open Access  
Boletín Semillas Ambientales     Open Access  
Boston College Environmental Affairs Law Review     Open Access   (Followers: 7)
Bothalia : African Biodiversity & Conservation     Open Access   (Followers: 1)
Built Environment     Full-text available via subscription   (Followers: 5)
Bulletin of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 15)
Bulletin of the American Meteorological Society     Open Access   (Followers: 51)
Bumi Lestari Journal of Environment     Open Access  
Canadian Journal of Earth Sciences     Hybrid Journal   (Followers: 23)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 50)
Canadian Journal of Soil Science     Full-text available via subscription   (Followers: 14)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 20)
Capitalism Nature Socialism     Hybrid Journal   (Followers: 27)
Case Studies in Chemical and Environmental Engineering     Open Access   (Followers: 1)
Casopis Slezskeho Zemskeho Muzea - serie A - vedy prirodni     Open Access  
Cell Biology and Toxicology     Hybrid Journal   (Followers: 12)
Chain Reaction     Full-text available via subscription  
Challenges in Sustainability     Open Access   (Followers: 12)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 25)
Chemico-Biological Interactions     Hybrid Journal   (Followers: 3)
Chemosphere     Hybrid Journal   (Followers: 17)
Child and Adolescent Mental Health     Hybrid Journal   (Followers: 71)
China Population, Resources and Environment     Full-text available via subscription   (Followers: 4)
Ciencia, Ambiente y Clima     Open Access   (Followers: 3)
City and Environment Interactions     Open Access   (Followers: 4)
Civil and Environmental Engineering     Open Access   (Followers: 8)
Civil and Environmental Engineering Reports     Open Access   (Followers: 9)
Civil and Environmental Research     Open Access   (Followers: 22)
CLEAN - Soil, Air, Water     Hybrid Journal   (Followers: 21)
Clean Technologies     Open Access   (Followers: 1)
Clean Technologies and Environmental Policy     Hybrid Journal   (Followers: 5)
Cleanroom Technology     Full-text available via subscription   (Followers: 1)
Climate and Energy     Full-text available via subscription   (Followers: 7)
Climate Change Ecology     Open Access  
Climate Change Economics     Hybrid Journal   (Followers: 33)
Climate Policy     Hybrid Journal   (Followers: 52)
Climate Resilience and Sustainability     Open Access   (Followers: 21)
Coastal Engineering Journal     Hybrid Journal   (Followers: 9)
Cogent Environmental Science     Open Access  
Columbia Journal of Environmental Law     Open Access   (Followers: 15)
Computational Ecology and Software     Open Access   (Followers: 11)
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 5)
Conservation and Society     Open Access   (Followers: 14)
Conservation Letters     Open Access   (Followers: 51)
Conservation Science     Open Access   (Followers: 30)
Consilience : The Journal of Sustainable Development     Open Access   (Followers: 3)
Contemporary Problems of Ecology     Hybrid Journal   (Followers: 4)
Critical Reviews in Environmental Science and Technology     Hybrid Journal   (Followers: 15)
Critical Reviews in Toxicology     Hybrid Journal   (Followers: 26)
Cuadernos de Investigación Geográfica / Geographical Research Letters     Open Access  
Culture, Agriculture, Food and Environment     Hybrid Journal   (Followers: 26)
Culture, Agriculture, Food and Environment     Hybrid Journal   (Followers: 11)
Current Environmental Engineering     Hybrid Journal  
Current Environmental Health Reports     Hybrid Journal   (Followers: 2)
Current Forestry Reports     Hybrid Journal   (Followers: 1)
Current Landscape Ecology Reports     Hybrid Journal   (Followers: 2)
Current Opinion in Environmental Science & Health     Hybrid Journal   (Followers: 1)
Current Opinion in Environmental Sustainability     Hybrid Journal   (Followers: 17)
Current Research in Ecological and Social Psychology     Open Access  
Current Research in Environmental Sustainability     Open Access   (Followers: 3)
Current Research in Green and Sustainable Chemistry     Open Access   (Followers: 1)
Current Research in Microbiology     Open Access   (Followers: 27)
Current Sustainable/Renewable Energy Reports     Hybrid Journal   (Followers: 9)
Current World Environment     Open Access   (Followers: 7)
Developments in Earth and Environmental Sciences     Full-text available via subscription   (Followers: 3)
Developments in Earth Surface Processes     Full-text available via subscription   (Followers: 1)
Developments in Environmental Modelling     Full-text available via subscription   (Followers: 8)
Developments in Environmental Science     Full-text available via subscription   (Followers: 4)
Developments in Integrated Environmental Assessment     Full-text available via subscription   (Followers: 5)
Die Bodenkultur : Journal of Land Management, Food and Environment     Open Access   (Followers: 2)
Disaster Prevention and Management     Hybrid Journal   (Followers: 32)
Discover Sustainability     Open Access   (Followers: 3)
disP - The Planning Review     Hybrid Journal   (Followers: 1)
Divulgación Científica     Open Access   (Followers: 1)
Drug and Chemical Toxicology     Hybrid Journal   (Followers: 16)
Duke Environmental Law & Policy Forum     Open Access   (Followers: 7)
Dynamiques Environnementales     Open Access   (Followers: 1)
E3S Web of Conferences     Open Access   (Followers: 2)
Earth and Environmental Science Transactions of the Royal Society of Edinburgh     Hybrid Journal   (Followers: 6)
Earth Interactions     Open Access   (Followers: 13)
Earth Science Informatics     Hybrid Journal   (Followers: 5)
Earth System Governance     Open Access  
Earth System Science Data (ESSD)     Open Access   (Followers: 8)
Earth Systems and Environment     Hybrid Journal   (Followers: 3)
Earthquake Science     Hybrid Journal   (Followers: 14)
EchoGéo     Open Access  
Eco-Thinking     Open Access   (Followers: 5)
Ecocycles     Open Access   (Followers: 6)
Ecohydrology     Hybrid Journal   (Followers: 11)
Ecohydrology & Hydrobiology     Full-text available via subscription   (Followers: 4)
Ecologia Aplicada     Open Access  
Ecología en Bolivia     Open Access  
Ecological Applications     Full-text available via subscription   (Followers: 218)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecological Complexity     Hybrid Journal   (Followers: 7)
Ecological Engineering     Hybrid Journal   (Followers: 4)
Ecological Engineering : X     Open Access  
Ecological Indicators     Hybrid Journal   (Followers: 23)
Ecological Informatics     Hybrid Journal   (Followers: 4)
Ecological Management & Restoration     Hybrid Journal   (Followers: 15)
Ecological Modelling     Hybrid Journal   (Followers: 96)
Ecological Monographs     Full-text available via subscription   (Followers: 39)
Ecological Processes     Open Access   (Followers: 2)
Ecological Questions     Open Access   (Followers: 4)
Ecological Research     Hybrid Journal   (Followers: 12)
Ecological Restoration     Full-text available via subscription   (Followers: 23)
Ecologist, The     Full-text available via subscription   (Followers: 23)
Ecology     Full-text available via subscription   (Followers: 483)
Ecology and Evolution     Open Access   (Followers: 104)
Ecology Letters     Hybrid Journal   (Followers: 343)
EcoMat : Functional Materials for Green Energy and Environment     Open Access   (Followers: 3)
Economics and Policy of Energy and the Environment     Full-text available via subscription   (Followers: 14)
Économie rurale     Open Access   (Followers: 3)
Ecoprint : An International Journal of Ecology     Open Access   (Followers: 6)
Ecopsychology     Hybrid Journal   (Followers: 8)
Ecosphere     Open Access   (Followers: 9)
Ecosystem Services     Hybrid Journal   (Followers: 10)
Ecosystems     Hybrid Journal   (Followers: 33)
Ecosystems and People     Open Access   (Followers: 3)
Ecotoxicology     Hybrid Journal   (Followers: 11)
Ecotoxicology and Environmental Safety     Hybrid Journal   (Followers: 12)

        1 2 3 4 5 | Last

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Journal Cover
Ambiente & Agua : An Interdisciplinary Journal of Applied Science
Journal Prestige (SJR): 0.263
Citation Impact (citeScore): 1
Number of Followers: 1  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1980-993X
Published by SciELO Homepage  [902 journals]
  • Quality of drained waters of the irrigated rice frames during the
           establishment of pre-germinated cultivation system

    • Abstract: Irrigated rice (Oriza sativa L.) pre-germinated production systems occupy approximately 100 thousand ha, annually cultivated in Rio Grande do Sul State, mainly in poorly drained areas, and with infestation of competing plants, especially red rice (Oriza sativa L.). This system constitutes the main technologic resource for rice crops produced on an ecological basis, by means of soil tillage and water management. Despite this, water outlets, specifically after seeding, have outstanding agronomic and environmental implications. Loss of nutrients and the physical and chemical quality of drained water have been questioned by public research and environmental institutions. This work evaluated the effects of different soil tillage systems and retention time of water in irrigated rice frames. The experiment was conducted in Viamão town, Rio Grande do Sul State. Two different soil tillage systems and four different times of frame drainage after seeding were investigated. Results showed that the main limiting attributes of water quality were turbidity, biochemical oxygen demand (BOD) and phosphorus (P) content, reaching 1800 TNU, 115 mg L-1, and 1.6 mg L-1, respectively. These attributes showed values higher than established environmental thresholds. Water quality was inappropriate to discharge directly into water courses, regardless of treatments.An alternative is the immediate placement in rice production areas, in more advanced development stages of plants. Pre-germinated rice crops require a system framework to avoid nutrient loss and consequent reduction of soil fertility.Resumo Os sistemas de produções de arroz (Oryza sativa L.) irrigado, pré-germinado ocupam uma superfície de aproximadamente 100 mil hectares, cultivados anualmente no Estado do Rio Grande do Sul, principalmente em áreas com deficiência de drenagem e com infestação de plantas competidoras, fundamentalmente o arroz vermelho (Oryza sativa L.). Esse sistema constitui a principal tecnologia para o cultivo de arroz de base ecológica, através do preparo do solo e do manejo da água nos quadros cultivados. Não obstante, a retirada da água dos quadros, especificamente após semeadura, tem implicações agronômicas e ambientais de destaque. A perda de nutrientes e a qualidade física e química da água drenada têm sido questionadas por instituições públicas, ambientais e de pesquisa. O objetivo desse trabalho foi avaliar os efeitos de diferentes formas de preparo do solo, assim como o tempo de permanência da água nos quadros de arroz irrigado pré-germinado. O experimento foi conduzido no município de Viamão - RS. Foram utilizados dois tipos de implementos para preparo do solo, associados a quatro tempos de drenagem dos quadros após a semeadura. Os resultados indicaram que os atributos mais limitantes em relação à qualidade da água, foram a turbidez, a demanda bioquímica de oxigênio (DBO) e os teores de fósforo, que chegaram a 1800 UNT, 115 mg L-1 e 1,6 mg L-1, respectivamente. A turbidez, assim como as concentrações de P e DBO, apresentaram-se superiores ao limite legal em todos os tratamentos avaliados. Devido o envolvimento da água no preparo do solo, sua qualidade foi imprópria para o descarte diretamente nos cursos hídricos, independentemente do implemento utilizado e dos diferentes períodos de decantação avaliados. Dessa forma, uma alternativa é a utilização dessas águas imediatamente em áreas de produção com arroz em estágios mais avançados de desenvolvimento. As lavouras de arroz pré-germinado, sobretudo nas produções de base ecológica, demandam uma adequação do sistema ao estabelecido pela legislação, contribuindo também para evitar perdas de nutrientes e a consequente redução da fertilidade dos solos.
       
  • Comparative analysis between the chlorination and ultraviolet radiation
           methods for the disinfection of bacteria-contaminated water

    • Abstract: The quality of water for human consumption has been a concern for large organizations and researchers, since the disinfection process, a step of great importance in water treatment plants, has not achieved its proper purpose. There have been frequent reports of the ineffectiveness of bacteria inactivation by the use of chlorine, which is the most used in Brazil, and also due to the formation of by-products such as trihalomethanes and haloacetic acids that are considered toxic to human health. The method of disinfection by ultraviolet radiation (UV) has been widely explored, due to its effectiveness in inactivating a wide variety of pathogens, in addition to the absence of by-product formation. The combined chlorine+UV process as chemical and physical disinfectants, respectively, is complementary and essential when looking for the safety of water for human consumption. The objective of this research was to statistically analyze the performance of disinfectants, chlorine and UV radiation, both separately and together, by inactivating the bacteria Escherichia coli and Pseudomonas aeruginosa and then incubating for 48 hours after having received the treatments. The statistical method showed that chlorine and UV obtained the same significance of 100% bacteria inactivation, and that within the determined time of 48 hours after the treatments the bacteria did not show reactivation. Thus, the study affirmed the usefulness of applying UV radiation as a complement to systems that use chlorine, with a special focus on residential water systems and supply.Resumo A preocupação com a qualidade da água para consumo humano tem sido alvo de grandes organizações e pesquisadores, visto que o processo de desinfecção, etapa de grande importância nas estações de tratamento de água, não tem alcançado o seu devido propósito. Isso se deve aos frequentes relatos na ineficiência da dose de inativação de bactérias pelo uso do cloro, que é o mais utilizado no Brasil, além da formação de subprodutos como trihalometanos e ácidos haloacéticos que são considerados tóxicos a saúde humana. O método de desinfecção por radiação ultravioleta (UV) tem sido amplamente explorado, devido à sua eficiência em inativar uma grande variedade de patógenos, além da ausência da formação de subprodutos. O processo combinado cloro+UV como agentes desinfetantes químicos e físicos, respectivamente, torna-os complementares e essenciais quando se busca a segurança da água para consumo humano. O objetivo desta pesquisa foi analisar estatisticamente o desempenho dos agentes desinfetantes, cloro e radiação UV, separadamente e em conjunto, por meio da inativação das bactérias, Escherichia coli e Pseudomonas aeruginosa, após 48 horas incubadas, após terem recebido os tratamentos. Concluiu-se que o cloro e a UV obtiveram a mesma significância de 100% de inativação das bactérias e que, dentro do tempo determinado de 48 horas após os tratamentos, as bactérias não mostraram reativação. Desta forma, o estudo realizado permitiu a consolidação da boa perspectiva de aplicação da radiação UV como complemento aos sistemas baseados no uso do cloro, com especial enfoque para sistemas e abastecimento de água residenciais.
       
  • Drinking water quality indices: a systematic review

    • Abstract: This analysis applied systematic review as a methodology for identifying, analyzing and interpreting data on the use of water quality indices for human consumption. Scientific articles were searched in the “PubMed”, “Scielo”, “ScienceDirect” and “Web of Science" databases, using the keywords “drinking water” and “water quality index”, with a custom interval between 2000 and 2020. The results indicated 82,573 published articles, with 16 of them being selected after a filtering process. The occurrence of 11 water quality indices was verified, including 47 water quality parameters used to assess the quality of drinking water, highlighting that the parameters pH, Nitrate, Turbidity, Chloride and Sulfate were the most used, cited in 10 of the 16 articles selected (62,5%). We suggest that future studies seek to propose regionalized water quality indicators for consumption, in order to consider local aspects in the evaluation process and to determine intervention priorities by health surveillance agencies.Resumo Esta análise aplica a revisão sistemática como metodologia para identificar, analisar e interpretar dados sobre o uso de índices de qualidade da água para consumo humano. Os artigos científicos foram pesquisados nas bases de dados “PubMed”, “Scielo”, “Science Direct” e “Web of Science”, usando as palavras-chave “água potável” e “índice de qualidade da água”, com um intervalo personalizado entre 2000 e 2020. Os resultados indicaram 82573 artigos publicados, sendo 16 deles selecionados após um processo de filtragem. Verificou-se a ocorrência de 11 índices de qualidade da água, incluindo 47 parâmetros de qualidade da água utilizados para avaliar a qualidade da água potável, destacando que os parâmetros pH, nitrato, turbidez, cloreto e sulfato foram os mais utilizados, citados em 10 dos 16 artigos selecionados (62,5%). Sugerimos que pesquisas futuras procurem propor indicadores regionalizados de qualidade da água para consumo, a fim de considerar aspectos locais no processo de avaliação e determinar prioridades de intervenção por órgãos de vigilância em saúde.
       
  • Nitrite build-up effect on nitrous oxide emissions in a laboratory-scale
           anaerobic/aerobic/anoxic/aerobic sequencing batch reactor

    • Abstract: Biological wastewater treatment processes with biological nitrogen removal are potential sources of nitrous oxide (N2O) emissions. It is important to expand knowledge on the controlling factors associated with N2O production, in order to propose emission mitigation strategies. This study therefore sought to identify the parameters that favor nitrite (NO2 -) accumulation and its influence on N2O production and emission in an anaerobic/aerobic/anoxic/aerobic sequencing batch reactor with biological nitrogen removal. Even with controlled dissolved oxygen concentrations and oxidation reduction potential, the first aerobic phase promoted only partial nitrification, resulting in NO2 - build-up (ranging from 29 to 57%) and consequent N2O generation. The NO2 - was not fully consumed in the subsequent anoxic phase, leading to even greater N2O production through partial denitrification. A direct relationship was observed between NO2 - accumulation in these phases and N2O production. In the first aerobic phase, the N2O/NO2 - ratio varied between 0.5 to 8.5%, while in the anoxic one values ranged between 8.3 and 22.7%. Higher N2O production was therefore noted during the anoxic phase compared to the first aerobic phase. As a result, the highest N2O fluxes occurred in the second aerobic phase, ranging from 706 to 2416 mg N m-2 h-1, as soon as aeration was triggered. Complete nitrification and denitrification promotion in this system was proven to be the key factor to avoid NO2 - build-up and, consequently, N2O emissions.Resumo Os processos de tratamento biológico de esgotos com remoção biológica de nitrogênio são potenciais fontes de emissão de óxido nitroso (N2O). No entanto, é importante ampliar o conhecimento dos principais fatores de controle associados à produção de N2O para propor estratégias de mitigação de sua emissão. O objetivo deste estudo foi identificar os parâmetros que favoreceram o acúmulo de nitrito (NO2 -) e sua influência na produção e emissão de N2O em um reator em batelada sequencial anaeróbio/aeróbio/anóxico/aeróbio com remoção de nitrogênio. Mesmo com a concentração de oxigênio dissolvido e o potencial redox controlados, a primeira fase aeróbia promoveu apenas a nitrificação parcial resultando em acúmulo de NO2 - (variando de 29 a 57%) e geração de N2O. Este NO2 - não foi totalmente consumido na fase anóxica subsequente promovendo uma produção ainda maior de N2O pela desnitrificação parcial. Foi observada uma relação direta entre o acúmulo de NO2 - nessas fases e a produção de N2O. Enquanto na primeira fase aeróbia a razão N2O/NO2 - variou entre 0,5 a 8,5%, na anóxica foi entre 8,3 e 22,7%. Portanto, houve uma maior produção de N2O durante a fase anóxica do que na primeira fase aeróbia. Com isso, os maiores fluxos de N2O ocorreram na segunda fase aeróbia, variando de 706 a 2416 mg N m-2 h-1, assim que a aeração foi acionada. A promoção da nitrificação e da desnitrificação completas neste sistema mostrou ser o fator chave para evitar o acúmulo de NO2 - e, consequentemente, a emissão de N2O.
       
  • Determination and evaluation of mercury concentration in fish in the São
           Francisco River Watershed, Brazil

    • Abstract: The objective of this work was to evaluate the bioaccumulation of mercury in 13 species of fish with different eating habits, captured in the Três Marias Reservoir, São Francisco Basin, from March 2012 to April 2013. The results obtained showed that the species with carnivorous eating habit presented the highest average concentrations of mercury in muscle, especially Serrasalmus brandtii (pirambeba) and Pygocentrus piraya (piranha), with concentrations of 0.4147 ± 0.2744 μg g-1 and 0.17774 ± 0.2980 μg g-1, respectively. Considering the average concentrations, all the species studied showed levels of mercury below the maximum limit of 0.5 μg g-1 in non-predatory fish and 1.0 μg g-1 in predatory fish, established by the Agência Nacional de Vigilância Sanitária. Taking each species into account, the minimum and maximum values of mercury in the muscular and hepatic tissues showed a wide dispersion. In 4% of the specimens of pirambeba and 7% of piranha, the contents of mercury in muscle exceeded the limit established by ANVISA for predatory fish, and therefore, were unfit for human consumption. The other species did not present muscle samples with Hg content above that established by law. Due to its carnivorous eating habit and its wide distribution in the São Francisco Basin, Serrasalmus brandtii can be considered a biomonitor, capable of bioaccumulating mercury, thus indicating the level of contamination in the aquatic environment in which it lives.Resumo Diante da toxicidade do mercúrio para o ser humano e para o meio ambiente, o objetivo deste trabalho foi avaliar a sua bioacumulação em 13 espécies de peixes com diferentes hábitos alimentares, capturados no reservatório de Três Marias, bacia do rio São Francisco, no período de março de 2012 a abril de 2013. Os resultados obtidos revelam que as espécies com hábito alimentar carnívoro apresentaram as maiores concentrações médias de mercúrio em músculo, com destaque para Serrasalmus brandtii (pirambeba) e Pygocentrus piraya (piranha), com concentrações de 0,4147 ± 0,2744 μg g-1 e 0,1774 ± 0,2980 μg g-1, respectivamente. Considerando as concentrações médias, todas as espécies estudadas apresentaram teores de mercúrio abaixo dos limites máximos de 0,5 μg g-1 em peixes não predadores e de 1,0 μg g-1 em peixes predadores, estabelecidos pela Agência Nacional de Vigilância Sanitária. Levando em conta cada espécie, os valores mínimos e máximos de mercúrio nos tecidos muscular e hepático demonstraram uma ampla dispersão. Em 4% dos espécimes de pirambeba e 7% de piranha, os teores de mercúrio em músculo ultrapassaram o limite estabelecido pela ANVISA para peixes predadores, e, portanto, sendo impróprios para o consumo humano. As demais espécies não apresentaram amostras de músculo com teor de Hg acima do estabelecido em lei. Devido ao seu hábito alimentar carnívoro e sua ampla distribuição na bacia do rio São Francisco, Serrasalmus brandtii pode ser considerada como biomonitor, capaz de bioacumular mercúrio, indicando, assim, o nível de contaminação desse metal no ambiente aquático em que vive.
       
  • Effect of allowable flow-rate variation and local head loss on maximum
           length of non-pressure compensated drip tape

    • Abstract: A challenge for the design of drip irrigation systems with non-pressure compensated emitters is to increase the maximum length of the lateral lines without significantly reducing water application uniformity. This work evaluated the effect of the flow-rate variation and the local head loss in the maximum length of drip tape with a non-pressure compensated flat emitter. The tests were carried out in a laboratory, using a collapsible drip tape non-pressure compensated in three 50-meter segments. The production line was configured to generate drip tapes without insertion of emitters and with closed emitters (0.30 m spacing). The experimental local head loss was compared with the Darcy-Weisbach equation's estimates using the Blasius friction factor. In the sequence, simulations were generated for the flow-rate variations of 10 and 20% for the emitter spacings of 0.30, 0.40, and 0.50m. The results showed that the local head loss had little influence on the lateral line's maximum length, generating variations of 2.5% on average. However, increasing the allowable flow rate variation from 10 to 20% resulted in a 34% increase in the lateral line maximum length. Also, the reduction in uniformity coefficients was less than 5%, enabling the indexes to remain above 90%. The adoption of higher flow rate variation values ​​allowed gains in the lateral line length with a small decrease in uniformity, making it an alternative to reduce design and operational costs.Resumo Um desafio para o dimensionamento de sistemas de irrigação por gotejamento com emissores não compensados é aumentar o comprimento máximo das linhas laterais sem reduzir significativamente a uniformidade de aplicação de água. Este trabalho teve como objetivo avaliar o efeito da variação da vazão permitida e da perda de carga no emissor no comprimento máximo da linha lateral utilizando mangueira gotejadora com gotejador plano não compensado. Os ensaios foram realizados em laboratório, utilizando-se três segmentos de 50 metros de fita gotejadora não compensada. A linha de produção foi configurada para gerar fitas gotejadoras com as seguintes características: sem inserção de emissores; com emissores fechados (espaçamento de 0,30 m). A perda de carga local obtida experimentalmente foi comparada com as estimativas da equação de Darcy-Weisbach usando o fator de atrito de Blasius. Na seqüência foram geradas simulações para as variações da vazão de 10 e 20%, para os espaçamentos entre emissores de 0,30; 0,40; e 0,50 m. A perda de carga localizada teve pouca influência no comprimento máximo da linha lateral, gerando variações médias de 2,5%. No entanto, o aumento da variação da vazão permitida de 10 para 20% resultou em um aumento de 34% no comprimento máximo da linha lateral. Além disso, a redução dos coeficientes de uniformidade avaliados foi inferior a 5%, permitindo que os índices permanecessem acima de 90%. A adoção de maiores valores de variação da vazão permitiu ganhos no comprimento da linha lateral com uma pequena diminuição na uniformidade, tornando-se uma alternativa para otimização do dimensionamento de fitas gotejadoras não compensadas.
       
  • Effects on circulation and water renewal due to the variations in the
           river flow and the wind in a Brazilian estuary lagoon complex

    • Abstract: The Mundaú-Manguaba Estuary Lagoon Complex is located on the coast of Alagoas state in Northeastern Brazil, and consists of two shallow lagoons, Mundaú and Manguaba, that form a system of choked lagoons which are connected to the Atlantic Ocean by a series of narrow channels with a single outlet which dynamically alters its position. This study uses the Hydrodynamic Environmental System, SisBaHiA® to investigate how variations in river discharge and wind influence hydrodynamic circulation, water renewal, salinity and temperature in the lagoons. The free surface positions, obtained by model, were compared with the free surface positions measured at two points of the complex, showing good agreement. The analyses were carried out for dry and wet seasons and extreme events with very high freshwater discharge. The channel system of the lagoons is an efficient filter in reducing tidal variability inside the lagoons. The tidal ranges in the Manguaba and Mundaú Lagoons are 90% and 80% lower, respectively, as compared with the values in the open boundary. The residence time calculated varied between 11 and 365 days and between 2 and 180 days for the Manguaba and Mundaú Lagoons, respectively, making it possible to identify possible stagnation areas. The results from the salt and heat transport model show a prolonged period with low salt concentrations and slow salinity recovery after the rainy season; the water temperature in the lagoons shows little spatial and temporal variation.Resumo O Complexo Estuarino Lagunar Mundaú-Manguaba está localizado no litoral do estado de Alagoas, no nordeste do Brasil, é formado por duas lagunas rasas, Mundaú e Manguaba, que constituem um sistema de lagunas sufocadas, conectadas com o oceano Atlântico por um conjunto de canais estreitos com uma única saída, que altera a sua posição dinamicamente. Este trabalho investiga como as variações do aporte fluvial e do vento influenciam a circulação hidrodinâmica, a renovação das águas, a salinidade e a temperatura nas lagunas usando o Sistema de Hidrodinâmica Ambiental computacional, SisBaHiA®. Os valores da posição da superfície livre obtidos pelo modelo foram confrontados com dados medidos em dois pontos do complexo, apresentando uma boa concordância. As análises foram realizadas para as estações seca e chuvosa e para um evento extremo, com vazões dos rios muito elevadas. O sistema de canais das lagunas é um filtro eficiente na redução os efeitos da maré nas lagunas. Dentro das Lagunas de Manguaba e Mundaú, as amplitudes da maré são reduzidas em cerca de 90% e 80%, respectivamente, em comparação com a fronteira aberta. O tempo de residência calculado variou entre 11 e 365 dias para a laguna Manguaba e entre 2 e 180 dias para Mundaú, permitindo identificar possíveis áreas de estagnação. Os resultados do modelo de transporte de sal e calor mostram um prolongado período com baixas concentrações de salinidade e uma lenta recuperação dos valores de salinidade após o período chuvoso; a temperatura da água nas lagunas apresenta pouca variação espacial e temporal.
       
  • Nutrient-use efficiency of Eucalyptus genotypes grown in Luvisol

    • Abstract: Superior productivity of genotypes in forest plantations depends on the supply, capture and use-efficiency of resources. In this context, knowledge regarding the nutritional efficiency of Eucalyptus influences farmers and researchers in decision-making and in the management of forest ecosystems. The aim of this research was to estimate nutrient-use efficiency in Eucalyptus genotypes planted in the state of Rio Grande do Sul, Brazil. We evaluated six potential genotypes at 43-month-old stands. Nutrient-use efficiency was calculated using the ratio of biomass and the amount of nutrients for each component of the biomass. Results here presented confirmed that there is synergism and antagonism between nutrients at the shoot level in the Eucalyptus genotypes. For stemwood, E. saligna showed the best utilization efficiency of N, P, K, S, and Mn; and E. urophylla × E. globulus for Mg, B, and Zn. Metabolic pathways control the production of biomass synthesized by each genotype and the differences between genotypes groups were on the basis of their nutrient-use efficiency in the biomass components. Stemwood was the component that showed the highest nutrient-use efficiency, while leaves presented the lowest nutrient-use efficiency. Additionally, our analyses identified how different each Eucalyptus genotype is and these traits may be used for clone allocation according to soil fertility.Resumo A produtividade de genótipos superiores em plantações florestais está em função da oferta, captura e eficiência de uso dos recursos. Nesse contexto, o conhecimento sobre a eficiência nutricional do Eucalyptus influencia agricultores e pesquisadores na tomada de decisões e no manejo de ecossistemas florestais. A pesquisa teve como objetivo estimar a eficiência no uso de nutrientes em genótipos de Eucalyptus plantados no Estado do Rio Grande do Sul, Brasil. Foram avaliados seis genótipos potenciais e as avaliações foram realizadas em povoamentos de 43 meses de idade. A eficiência do uso de nutrientes foi calculada usando a razão de biomassa e a quantidade de nutrientes para cada componente da biomassa. Os resultados aqui apresentados confirmam que existe sinergismo e antagonismo entre os nutrientes no nível da parte aérea nos genótipos de Eucalyptus. Para a madeira do fuste, E. saligna apresentou a melhor eficiência de utilização de N, P, K, S e Mn; e E. urophylla × E. globulus para Mg, B e Zn. As vias metabólicas controlam a produção de biomassa sintetizada por cada genótipo e as diferenças entre os grupos de genótipos foram baseadas na eficiência do uso de nutrientes nos componentes da biomassa. A madeira do caule foi o componente que apresentou maior eficiência de uso de nutrientes, enquanto as folhas apresentaram a menor eficiência de uso de nutrientes. Mas, além disso, nossas análises identificaram o quão diferente é cada genótipo de Eucalyptus e essas características podem ser usadas para alocação de clones de acordo com a fertilidade do solo.
       
  • A hybrid approach associating flow network modeling with AHP-Entropy for
           simulating and ranking water-demand management alternatives

    • Abstract: In view of the water crises historically experienced by Brazil’s semi-arid region, it is necessary to search for methodological tools that allow us to propose efficient alternatives for managing water demand. In this regard, the present study developed and applied a hybrid approach of flow network modeling and the Analytic Hierarchy Process (AHP) combined with Shannon’s entropy for simulating and prioritizing water demand management alternatives in the Epitácio Pessoa Reservoir in the Brazilian semiarid region. The approach initially performed simulations of the hydro system flow network to explore rational alternatives that evaluated the following criteria: meet the demands of human supply, meet the demands for irrigation, maintain the reservoir above the target volume, and reduce consumption. Subsequently, Shannon's entropy was used to assess the importance of the criteria and the multicriteria analysis of ranking of alternatives was built. Finally, a sensitivity analysis of the model was performed regarding the dependence on respective weights of the criteria. The results made enabled evaluation of the hydro system’s water security, highlighting insufficient supply by the single measure of water management transposition of the São Francisco River, and based on the hierarchy of alternatives, suggesting actions to improve the sustainability of water use, such as reuse of water, reduction of losses in supply systems and increasing irrigation efficiency. The proposed hybrid approach permitted the synthesis of the simulation’s results, which may simplify and support the decision-making process in water-demand management.Resumo Diante das crises hídricas historicamente vivenciadas pelo semiárido do Brasil, é necessário buscar ferramentas metodológicas que possibilitem propor alternativas eficientes de gerenciamento da demanda de água. Nesse contexto, o presente estudo desenvolveu e aplicou uma abordagem híbrida de modelagem de rede de fluxo e Analytic Hierarchy Process (AHP) combinada à entropia de Shannon, para simular e hierarquizar alternativas de gerenciamento da demanda de água do reservatório Epitácio Pessoa, no semiárido brasileiro. A abordagem inicialmente realizou simulações da rede de fluxo do hidrossistema admitindo alternativas voltadas à sustentabilidade, avaliando os critérios: atendimento às demandas de abastecimento humano, atendimento à demanda de irrigação, manutenção do reservatório acima do volume meta e redução de consumo. Posteriormente, a entropia de Shannon foi utilizada para aferir a importância dos critérios, e foi desenvolvida a análise multicritério de hierarquização das alternativas. Por fim, foi realizada uma análise de sensibilidade do modelo quanto a dependência dos pesos dos critérios. Os resultados possibilitaram avaliar a segurança hídrica do hidrossistema, apontando insuficiência do abastecimento pela medida única de gerenciamento da transposição do rio São Francisco, permitindo sugerir, baseado na hierarquização de alternativas, medidas voltadas à sustentabilidade do uso da água que adotem mecanismos poupadores, reuso, reduzam as perdas e aumentem a eficiência na irrigação. A abordagem híbrida proposta permitiu sintetizar os resultados da simulação, o que pode apoiar e simplificar o processo de tomada de decisão no gerenciamento da demanda de água.
       
 
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