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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Wide-spaced furrow irrigation effects on vertisols under corn production in the Mississippi Delta

Freeland, Thomas Barton, III 10 May 2024 (has links) (PDF)
The majority of soils in the Mississippi Delta are vertisols, which are prone to waterlogging and can negatively affect crop production. Thus, our goal was to investigate whether widening the spacing of irrigated furrows will relieve waterlogging and improve corn productivity. The effects of furrow irrigation spacing on corn grain yield and quality were investigated for three years at a research station and a commercial farm. Widening furrow irrigation spacing up to 8 m never decreased corn grain yield, and higher corn yields were documented in 8 m furrow spacing compared to narrower irrigation spacing. Irrigation water was found to spread underground at least 4 m perpendicular to the irrigated furrow and refill the soil from the bottom up. As irrigation spacing widened, water flow accelerated through the field and infiltration was reduced, especially for the soil away from the irrigated furrow. This suggests irrigation water savings of up to 30 % from adopting wide-spaced furrow irrigation in vertisols.
32

Linking GIS and a surface irrigation model to evaluate regional effects of furrow irrigation strategies

Faux, Russell N. 30 April 1996 (has links)
The shallow aquifer in Northeast Malheur County, Oregon is polluted with Nitrates at concentrations exceeding federal drinking water standards. Efforts to solve the groundwater problems in this area have focused on developing farm management practices that will increase groundwater quality while maintaining agricultural production. Furrow irrigation is the dominant practice for irrigating row crops in this region. One potential way to improve water quality is to increase furrow irrigation performance on a regional scale. In this study a surface irrigation model, SRFR, was linked to a geographic information system (GIS) for the purpose of evaluating alternate furrow irrigation strategies in Malheur County, Oregon. SRFR is a physically based model that simulates water flow and distribution in irrigated furrows. The model accepts the management parameters that influence the outcome of an irrigation and in return provides measures of water application efficiency, amount of deep percolation, amount of surface run-off, and other performance indicators. The GIS, constructed using ARC/INFO software, contains the spatial data required to run SRFR on individual fields in the region. The data for the GIS were acquired using many different sources and techniques in order to meet the input resolution required by the irrigation model. The primary goal of this research was to develop a tool for evaluating irrigation practices on a regional scale, accounting for the diversity of physical circumstances and management practices that occur within a complex of several hundred farms. The particular application of this tool was for control of nitrate pollution of groundwater in the vicinity of Ontario, Oregon. The integrated system was used to estimate a base condition irrigation that is representative of current irrigation practices. The system was then used to assess irrigation performance using three alternative practices: 1) separate management of wheel and nonwheel compacted furrows; 2) use of an automated control system to vary application set times; and 3) cutback irrigation. Although this represents only a limited assessment of the alternatives that might be considered for the study area, preliminary results suggest that under certain field conditions irrigation efficiency can potentially improve more then 20% over the base condition using alternate strategies. The system demonstrated tremendous potential for identifying trends and variability in system performance in the region. / Graduation date: 1997
33

Desempenho operacional de semeadora em função de mecanismos de corte, velocidade e solos, no sistema plantio direto do milho

Mahl, Denise [UNESP] 02 June 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-02Bitstream added on 2014-06-13T20:22:26Z : No. of bitstreams: 1 mahl_d_dr_botfca.pdf: 815471 bytes, checksum: be15fff752262a6a07097824be496849 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / The success of no tillage system is directly related to the selection and efficiency of the seeders components as well as of the suitability of the forward speed and soil and vegetable covering characteristics. This research was carried out in a corn (Zea mays L.) field aiming to evaluate the operational and energetic performance of a no-tillage seeder in two soil types with different vegetable covering and with different forward speeds, furrow opener and cut elements. The performance were evaluated through parameters of seeds longitudinal uniformity distribution, seeding depth, soil mobilized area, tractor and seeder tractive wheel slips, draw bar pull and power requirements, fuel consumption, plantules emergency, culture growing and productivity. The experiments were carried out in two different farms. One at Lageado Experimental Farm, which the soil is classified as Nitossolo Vermelho distroférrico covered with 7 t.ha-1 of dry matter of corn, lupine and weed residues. The other experiment was carried out at São Manuel Experimental Farm, wich soil is classified as Latossolo Vermelho covered with 20 t.ha-1 of dry matter of Brachiaria spp and corn residues. Both experiments designs were 2x3x3 factorial in randomized blocks with four replications. The factors examined were: two furrow opener mechanisms (doubledisk and chisel opener); three tractor-seeder forward speeds (5.5; 7.9 and 10.1 km.h-1); and three covering cut mechanisms (smoothly, fluted and notched cut disks). The soil type and vegetable coverage interfered in the global seeder 4 performance and their cut and furrow opener components. Comparing with the experiment carried in Botucatu, the experiment carried in São Manuel provided larger values of: seeding depth, tractor wheel slip, percentage of soil covering, draw bar pull and power requirements, hourly... (Complete abstract, click electronic access below)
34

Custo da cobrança de agua na produção do tomate de mesa sob irrigação por sulcos / Evaluation of irrigation water cost in the fresh market production

Campos, Murilo Avary de 12 October 2004 (has links)
Orientador: Roberto Testezlaf / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-06T00:09:33Z (GMT). No. of bitstreams: 1 Campos_MuriloAvaryde_M.pdf: 1359093 bytes, checksum: 3d8eabf625260c6dfd1066bd7338c14e (MD5) Previous issue date: 2004 / Resumo: A utilização do sistema de irrigação por sulcos por tomaticultores, vem determinando um consumo excessivo de água na exploração da cultura e tornando uma preocupação financeira para os produtores do tomate de mesa com a criação de uma legislação onde se prevê a cobrança pela captação e uso da água. O objetivo do presente trabalho foi proceder a avaliação da demanda de recursos hídricos na produção do tomate de mesa pelo sistema de irrigação por sulcos, simulando o impacto da cobrança de água no custo de produção do tomate de mesa. Os eventos de irrigação de uma propriedade produtora de tomate de mesa localizada no Município de Estiva Gerbi/SP, foram monitorados durante a safra de 2003. A lâmina de irrigação aplicada pelo produtor foi estimada a partir da vazão do sistema e do tempo de irrigação, sendo a umidade do solo monitorada através de três baterias de tensiômetros e os valores da evapotranspiração de referência, determinados pelos dados coletados em uma estação meteorológica automática instalada na propriedade. A determinação do custo de produção foi realizada utilizando-se o modelo proposto pelo Instituto de Economia Agrícola/SP, que permitiu, também, a simulação do custo para diferentes valores de eficiência de irrigação. A lâmina total de água aplicada pela irrigação foi de 1.326 mm, o que resultou em uma baixa eficiência de uso de água (EUA) de 4 Kg/m3 e uma eficiência de aplicação da água (EA) de 32%. O custo da cobrança da água representou 0,4% do custo de produção, considerado pouco significativo para o valor total de produção. Portanto, com os resultados obtidos, pode-se concluir que a política de cobrança pelo uso da água certamente não inibirá a continuidade do uso excessivo dos recursos hídricos dessa atividade agrícola. Entretanto, a demonstração ao produtor do custo associado ao bombeamento poderá contribuir para a sua conscientização e a recomendação do uso do tensiômetro como uma ferramenta prática e útil, auxiliaria a realização do manejo apropriado da irrigação por sulcos e obtenção da redução no seu custo de produção / Abstract: The use of furrow irrigation system by tomato farmers determined an excessive water use in the crop production. As a result of a state legislation proposal to tax the water use the tomato growers being to have a new financial concern. The objective of the present work consisted to evaluate the water demand in the production of fresh market tomato irrigated by furrow system and to simulate the impact of the water taxation in its production. The irrigation events of a fresh market tomato farm located in the City of Estiva Gerbi, SP, were monitored during the 2003 harvest. The depth of irrigation applied by the farmer was estimated from the outflow of the pump system and the time of irrigation. The soil moisture were monitored through three batteries of tensiometer and the values of the reference evapotranspiration were determined using the data collected in an automatic meteorological station installed in the property. The determination of the production cost was made by using the model proposed for the Agribusiness Economic Institute/SP, which also allowed the simulation of the production cost for different values of irrigation efficiency. The total irrigation depth used in the production was 1,326 mm, which resulted in a low water use efficiency (WUE) of 4 Kg/m3 and water application efficiency (AE) of 32%. The water tax payment represented only 0.4% of the total production cost, considered not significant for the total value of production. Therefore, based in the results, it can be concluded that the taxation policy of the irrigation water usage certainly will not restrain the continuation of the excessive use of the water resources in this agricultural activity. However, the demonstration to the growers of the values associated to the pumped cost can contribute to the problem awareness and the recommendation of tensiometer use as practical and useful tool to the irrigation water management in furrow irrigation would help to obtain a reduction in production cost. Key words: production cost, water taxation, water demand, application efficiency / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
35

Gravimetrická měření a opakovaná nivelace na polygonu Tetčice / Gravity measurements at Tetčice polygon

Bitalová, Katarína January 2014 (has links)
This master's thesis deals with measurements of highs and gravity of points polygon located in village Tetčice, through which is crossing a eastern fault of Boskovice furrow. With repeated measurement should be proved effect to high levels of groundwater. Repeated measurements are realized in the range 2 stages. In thesis is in detail described calculation complete Bouguer gravity anomaly and their quantitative interpretation. From the gravimetric of dates is created map of complete Bouguer gravity anomaly and interpretative profile through Boskovice furrow. Interpretative profile has localized fault, whose tectonic activity belong to possible factors level movement in the village. Level measurements meets the requirement of precise levelling. The results of the measurements are compared and discussed with the previous stages of the research.
36

Opakovaná nivelace na vodním zdroji Tetčice / Precise repeated leveling measurements at Tetčice water reservoir

Čáp, Pavel January 2012 (has links)
This master’s thesis deals with the vertical movements of foundation soil in village Tetčice. In the first part describes geological structures and problems in locality. A next chapter deals with surveying vertical movements, measurements and evaluation. As addition is measurement actually groundwater level depending on the line levelling.
37

Elucidating the mechanism of AP axis alignment in the C. elegans embryo

Bhatnagar, Archit 24 October 2023 (has links)
Development of a single-cell embryo into an adult multi-cellular organism features the establishment of upto three anatomical body axes - anteroposterior, dorsoventral and left-right. It has been observed in many organisms that these body axes can consistently orient relative with respect to the geometric features of the embryo in many organisms. One such example is observed in the model organism Caenorhabditis elegans (C. elegans), where the Anteroposterior (AP) axis coincides with the geometric long axis of the ellipsoidal embryo -- the shape being imposed by the surrounding eggshell. In C. elegans, the Anteroposterior axis is established at the one-cell stage via its polarization by PAR polarity proteins. This cell polarization proceeds via a self-organized mechanochemical feedback between the PAR proteins and mechanical flows in the actomyosin cortex, resulting in the formation of two mutually exclusive domains of Anterior PAR and Posterior PAR proteins on the cortex denoting the future anterior and posterior end of the embryo -- and thus establishing the Anteroposterior axis. The initial orientation of the Anteroposterior axis is determined by the site of sperm entry at fertilization. However, the nascent Anteroposterior axis that forms after fertilization is observed to actively re-orient -- indicated by the movement of the PAR domains and concurrent migration (here termed posteriorisation) of the sperm-donated male pronucleus -- such that it aligns with the long axis of the ellipsoidal embryo, if it is not already aligned. In effect, the site of sperm entry only determines which half of the embryo becomes the posterior half of the embryo. This phenomenon of active re-orientation of the Anteroposterior axis, that ensures that the Anteroposterior axis aligns with the long axis of the embryo, is termed Anteroposterior axis alignment. The work described in this thesis investigates the mechanism of this Anteroposterior axis alignment in the C. elegans embryo. Anterior-directed flows in the actomyosin cortex observed during Anteroposterior axis establishment have also been found to be essential for Anteroposterior axis alignment. In this thesis, two possible mechanisms of Anteroposterior axis alignment are considered, both of which are consequences of these cortical flows. Cortical flows at the embryo surface can drive flows in the bulk cytoplasm in the embryo, generating cytoplasmic flows which point towards the sperm-donated male pronucleus as it posteriorises. Previous studies have proposed that these cytoplasmic flows could push onto the male pronucleus, and due to the ellipsoidal geometry of the embryo, drive it towards the closest tip of the embryo. This proposed mechanism is referred to as the cytoplasmic flow-dependent mechanism in this thesis. Another mechanism proposed in this thesis postulates that the reorientation of the Anteroposterior axis occurs via the repositioning of the pseudocleavage furrow. The pseudocleavage furrow is a contractile ring-like structure that forms at the boundary of the two PAR domains during Anteroposterior axis establishment. The pseudocleavage furrow forms as a result of compressive alignment of actin filaments in the actomyosin cortex due to cortical flows. In cases where the Anteroposterior axis is not aligned with the long axis of the embryo, the pseudocleavage furrow is not perpendicular to the long axis of the embryo. In such cases, active anisotropic stresses generated in the actomyosin cortex could force the rotation of the pseudocleavage furrow akin to an elastic rubber-band on an ellipsoid, and cause the Anteroposterior axis to re-orient towards the long axis of the embryo. This proposed mechanism is referred to as the pseudocleavage furrow-dependent mechanism in this thesis. This thesis investigates the role played by the two mechanisms in Anteroposterior axis alignment. This is accomplished in the following way: a theoretical model of the Anteroposterior axis alignment is introduced, consisting of a description of the actomyosin cortex as an active nematic fluid present on the 2D surface of a fixed ellipsoid representing the embryo. This description of the cortex incorporates both the cytoplasmic flow-dependent mechanism and the pseudocleavage furrow-dependent mechanism. RNAi experiments in the C. elegans embryo that remove the pseudocleavage furrow, in conjuction with numerical simulations using the theoretical model, show that the pseudocleavage furrow-dependent mechanism is the predominant mechanism that drives Anteroposterior axis alignment, while cytoplasmic flow-dependent mechanism plays only a minor role. RNAi experiments that modify the geometry of the C. elegans embryo -- specifically, generate rounder embyros -- show that embryo geometry can influence the rate of re-orientation of the Anteroposterior axis during Anteroposterior axis alignment -- with slower Anteroposterior axis alignment in rounder embryos. Such an relation between embryo geometry and Anteroposterior axis alignment is found to be consistent with pseudocleavage furrow-dependent mechanism, both via predictions made using the theoretical model and using a simplified effective model of a contractile ring (or elastic rubber-band) on a fixed ellipsoid. Altogether, the work presented in this thesis shows Anteroposterior axis alignment observed in the C. elegans embryo is driven primarily by the anisotropic stresses in the actomyosin cortex that generate the pseudocleavage furrow. The work here also shows that the Anteroposterior axis alignment process is sensitive to the geometry of the embryo. In effect, active mechanical flows in the actomyosin cortex translate the ellipsoidal geometry of the embryo into a robust orientation of the Anteroposterior axis of the C. elegans embryo. Mechanical flows such as these are not exclusive to C. elegans, nor are specific orientations of the body axes with respect to the embryo geometry. The results in this thesis thus point towards a possibly general role of the interactions between mechanical flows and embryo geometry to properly orient the body axes of the developing embryos of many multi-cellular organisms.:Contents Abbreviations iii Abstract iv 1 Introduction 1 1.1 Cytoskeleton 3 1.1.1 Main constituents of the cytoskeleton 3 1.1.2 Actomyosin cortex 7 1.2 Hydrodynamic theory of active fluids 8 1.2.1 Conservation Laws 9 1.2.2 Continuously broken symmetries 11 1.2.3 Irreversible thermodynamics of active fluids 13 1.2.4 Constitutive equations of active nematic fluids 19 1.3 C. elegans as a model organism 21 1.3.1 Early embryogenesis in C. elegans 22 1.4 AP axis establishment in C. elegans 24 1.4.1 PAR polarity system . 24 1.4.2 Mechanism of AP axis establishment 26 1.4.3 AP axis alignment 27 1.5 Overview 29 2 A theoretical model for AP axis alignment 30 2.1 A model of AP axis establishment in C. elegans 30 2.1.1 Turing-like system for PAR polarity system 31 2.1.2 Active isotropic description of actomyosin cortex 33 2.1.3 Guiding cues for AP axis establishment 34 2.1.4 Full model of AP axis establishment in [1] 35 2.2 A model of pseudocleavage furrow formation in C. elegans 36 2.2.1 Dynamics of Actin alignment 37 2.2.2 Active stress generated by alignment of actin filaments 38 2.3 A model of AP axis alignment in C. elegans 39 2.3.1 A thin film active nematic description of the cortex 40 2.3.2 Description of the Cytoplasm and Male pronucleus 46 2.3.3 Numerical simulations of the theoretical model 48 3 Materials and Methods 52 3.1 Culture conditions, strains and worm handling 52 3.2 Genetic perturbations by RNAi 53 3.3 Time-lapse microscopy 53 3.4 Image analysis 54 3.4.1 Pre-processing 54 3.4.2 Tracking posteriorisation of the male pronucleus 56 3.4.3 Measuring cortical flows 66 3.4.4 Measuring cytoplasmic flows 67 3.5 Data analysis 67 4 Experimental investigation of AP axis alignment 71 4.1 Characterising AP axis alignment in unperturbed embryos 71 4.2 Cortical flows are required for AP axis alignment 76 4.3 Role of Pseudocleavage furrow in AP axis alignment 83 4.3.1 Removing Pseudocleavage furrow via RNAi 83 4.3.2 Comparing numerical simulations to experimental results 88 4.4 Role of embryo geometry in AP axis alignment 99 4.4.1 Rounder embryos show slower AP axis alignment 99 4.4.2 Relation between embryo geometry and AP axis alignment 108 4.5 Additional experiments 118 4.5.1 Exploring relation between embryo geometry and AP axis alignment in ima-3 RNAi embryos 118 4.5.2 Are pseudocleavage furrow-dependent and cytoplasmic flow-dependent mechanisms sufficient to explain AP axis alignment? 121 4.5.3 Role of microtubules in AP axis alignment 127 5 Conclusions and Outlook 134 Appendix 139 Bibliography 142 List of publications 156 Acknowledgements 157
38

Desempenho operacional de semeadora em função de mecanismos de corte, velocidade e solos, no sistema plantio direto do milho /

Mahl, Denise, 1976- January 2006 (has links)
Abstract: The success of no tillage system is directly related to the selection and efficiency of the seeders components as well as of the suitability of the forward speed and soil and vegetable covering characteristics. This research was carried out in a corn (Zea mays L.) field aiming to evaluate the operational and energetic performance of a no-tillage seeder in two soil types with different vegetable covering and with different forward speeds, furrow opener and cut elements. The performance were evaluated through parameters of seeds longitudinal uniformity distribution, seeding depth, soil mobilized area, tractor and seeder tractive wheel slips, draw bar pull and power requirements, fuel consumption, plantules emergency, culture growing and productivity. The experiments were carried out in two different farms. One at Lageado Experimental Farm, which the soil is classified as ‘Nitossolo Vermelho distroférrico’ covered with 7 t.ha-1 of dry matter of corn, lupine and weed residues. The other experiment was carried out at São Manuel Experimental Farm, wich soil is classified as ‘Latossolo Vermelho’ covered with 20 t.ha-1 of dry matter of Brachiaria spp and corn residues. Both experiments designs were 2x3x3 factorial in randomized blocks with four replications. The factors examined were: two furrow opener mechanisms (doubledisk and chisel opener); three tractor-seeder forward speeds (5.5; 7.9 and 10.1 km.h-1); and three covering cut mechanisms (smoothly, fluted and notched cut disks). The soil type and vegetable coverage interfered in the global seeder 4 performance and their cut and furrow opener components. Comparing with the experiment carried in Botucatu, the experiment carried in São Manuel provided larger values of: seeding depth, tractor wheel slip, percentage of soil covering, draw bar pull and power requirements, hourly... (Complete abstract, click electronic access below) / Orientador: Carlos Antonio Gamero / Coorientador: Sérgio Hugo Benez / Banca: Carlos Eduardo Angeli Furlani / Banca: Antonio Jose da Silva Maciel / Banca: Rubens Siqueira / Banca: Geraldo da Silva / Doutor
39

Ocorrência de desreguladores endócrinos em cultura de milho irrigada com efluentes urbanos tratados

Castro, Carmen Maria Barros de January 2010 (has links)
Devido à escassez de recursos hídricos, efluentes de plantas de tratamento de águas residuárias têm sido reutilizadas ou recicladas em todo o mundo. Em algumas regiões áridas e em particular em regiões semi-áridas, o reuso de água tem sido reconhecido como um valioso recurso. Entretanto, dependendo da natureza do uso, surgem preocupações sobre potenciais riscos associados à presença de patógenos e contaminantes e a saúde humana. Uma grande variedade de contaminantes orgânicos pode estar presente nos esgotos domésticos e ser recirculado pelo ambiente. Alguns desses compostos apresentam o potencial de desregular as funções normais do sistema endócrino dos organismos e assim, causar efeitos adversos sobre a saúde humana. Entre esses compostos, incluem-se os hormônios estrógenos naturais e sintéticos. Nesse trabalho, desenvolvido na Estação Experimental de Tratamento de Águas Residuárias Urbanas do IPH/UFRGS, localizada nas dependências da ETE São João – Navegantes / DMAE / Porto Alegre / RS, foi investigada a ocorrência de hormônios naturais e sintéticos em grãos de milho cultivados por processo de irrigação por sulcos com efluentes domésticos tratados. O método analítico utilizado para quantificação dos hormônios de interesse foi a cromatografia líquida de alto desempenho (HPLC). Os resultados obtidos confirmam a presença de hormônios naturais e sintéticos no esgoto bruto e nos efluentes tratados, mas em concentrações extremamente baixas e não indicam processo de transferência ou acúmulo desses contaminantes para os grãos de milho. / Due to the scarcity of fresh water resources, effluents from wastewater treatment plants have increasingly been reclaimed and reused around the world. In some arid and semiarid regions, in particular, reclaimed water has been recognized as a valuable resource for non-potable use such as irrigating crops. However, depending on the nature of application, there is concern about potential risks associated with pathogens and organic contaminants to the environment and human health. A wide range of organic contaminants may be present in wastewater and the environment receiving it. These include natural and synthetic estrogens have the potential to disrupt the normal function (s) of endocrine systems in organisms and thus causing health effects on wildlife and humans. In the present work, developed at “Estação Experimental de Tratamento de Águas Residuárias Urbanas do IPH/UFRGS”, located on the ETE São João – Navegantes /DMAE / Porto Alegre /RS, was investigated the occurrence of natural and synthetic hormones in corn’s grain (Zea mays) cultivated by furrow irrigation of treated domestic effluents. The analytic method used for the hormones quantification was the High Performance Liquid Chromatography (HPLC). The results confirm the presence of natural and synthetic hormones on the untreated and treated effluents, although with a very low concentration and not indicated accumulation of this one to the corn’s grain.
40

Ocorrência de desreguladores endócrinos em cultura de milho irrigada com efluentes urbanos tratados

Castro, Carmen Maria Barros de January 2010 (has links)
Devido à escassez de recursos hídricos, efluentes de plantas de tratamento de águas residuárias têm sido reutilizadas ou recicladas em todo o mundo. Em algumas regiões áridas e em particular em regiões semi-áridas, o reuso de água tem sido reconhecido como um valioso recurso. Entretanto, dependendo da natureza do uso, surgem preocupações sobre potenciais riscos associados à presença de patógenos e contaminantes e a saúde humana. Uma grande variedade de contaminantes orgânicos pode estar presente nos esgotos domésticos e ser recirculado pelo ambiente. Alguns desses compostos apresentam o potencial de desregular as funções normais do sistema endócrino dos organismos e assim, causar efeitos adversos sobre a saúde humana. Entre esses compostos, incluem-se os hormônios estrógenos naturais e sintéticos. Nesse trabalho, desenvolvido na Estação Experimental de Tratamento de Águas Residuárias Urbanas do IPH/UFRGS, localizada nas dependências da ETE São João – Navegantes / DMAE / Porto Alegre / RS, foi investigada a ocorrência de hormônios naturais e sintéticos em grãos de milho cultivados por processo de irrigação por sulcos com efluentes domésticos tratados. O método analítico utilizado para quantificação dos hormônios de interesse foi a cromatografia líquida de alto desempenho (HPLC). Os resultados obtidos confirmam a presença de hormônios naturais e sintéticos no esgoto bruto e nos efluentes tratados, mas em concentrações extremamente baixas e não indicam processo de transferência ou acúmulo desses contaminantes para os grãos de milho. / Due to the scarcity of fresh water resources, effluents from wastewater treatment plants have increasingly been reclaimed and reused around the world. In some arid and semiarid regions, in particular, reclaimed water has been recognized as a valuable resource for non-potable use such as irrigating crops. However, depending on the nature of application, there is concern about potential risks associated with pathogens and organic contaminants to the environment and human health. A wide range of organic contaminants may be present in wastewater and the environment receiving it. These include natural and synthetic estrogens have the potential to disrupt the normal function (s) of endocrine systems in organisms and thus causing health effects on wildlife and humans. In the present work, developed at “Estação Experimental de Tratamento de Águas Residuárias Urbanas do IPH/UFRGS”, located on the ETE São João – Navegantes /DMAE / Porto Alegre /RS, was investigated the occurrence of natural and synthetic hormones in corn’s grain (Zea mays) cultivated by furrow irrigation of treated domestic effluents. The analytic method used for the hormones quantification was the High Performance Liquid Chromatography (HPLC). The results confirm the presence of natural and synthetic hormones on the untreated and treated effluents, although with a very low concentration and not indicated accumulation of this one to the corn’s grain.

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