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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.
71

Efeito de subdoses de maturadores de cana-de-açúcar na cultura do milho / Sublethal rates effect of sugarcane ripeners in maize

Felisberto, Patrícia Aparecida de Carvalho 23 February 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-26T13:09:56Z No. of bitstreams: 2 Dissertação - Patrícia Aparecida de Carvalho Felisberto - 2015.pdf: 5137723 bytes, checksum: 1a2d107b747e1e556b5cc29325451197 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-26T13:14:03Z (GMT) No. of bitstreams: 2 Dissertação - Patrícia Aparecida de Carvalho Felisberto - 2015.pdf: 5137723 bytes, checksum: 1a2d107b747e1e556b5cc29325451197 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-05-26T13:14:03Z (GMT). No. of bitstreams: 2 Dissertação - Patrícia Aparecida de Carvalho Felisberto - 2015.pdf: 5137723 bytes, checksum: 1a2d107b747e1e556b5cc29325451197 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the field aerial application of sugarcane ripeners, spraying should reach its target without drifting occurs, avoiding contamination of surrounding crops. The aim of this research was to evaluate the effects of sugarcane ripeners simulated drift using sublethal rates in maize when applied to V4 and V8 stages of development. For this purpose were installed two trials on the Federal University of Goiás, Regional Jataí. Each plot contained 10 rows of SYN 7G17 maize hybrid. Each trial consisted of eight treatments established in design with randomized blocks where the treatments were arranged at factorial design of 2 x 4, plus one control treatment, with four replications. First factor corresponds to spraying at the V4 and V8 stages of maize and the second factor to sublethal rates of 3; 6; 9 to 12% of 475.2 g a.i. ha-1 ethephon (Trial I), 216.0 g a.e. ha-1 glyphosate (Trial II) and 15.0 g a.i. ha-1 sulfometuron methyl (Trial III). At 20 and 36 days after sowing, when the maize were in V4 and V8, respectively, applications of ripeners were performed.The phytotoxicity effects were noticeable in both stages at 7, 14, 21, 28 and 42 days after spraying only for Trial III. For glyphosate, the length and diameter of ear were reduced in size to both stages. Maize is sensitive to sublethal rates starting from 0.45 g a.i. ha-1 sulfometuron methyl in V4 and V8 stages of development. The lower grain yield was only to plants subjected to sublethal doses of sulfometuron methyl, being lower yield when drift occurs in the V8 stage of development compared to the V4 stage. / Na aplicação aérea de maturadores de cana-de-açúcar, a pulverização deve atingir o seu alvo sem que ocorra deriva, evitando a contaminação de culturas circunvizinhas. Objetivou-se com a pesquisa avaliar o efeito de subdoses de maturadores de cana-de-açúcar na cultura do milho quando aplicadas em estádios de desenvolvimento V4 e V8. Foram instalados três ensaios na Fazenda da Universidade Federal de Goiás, UFG, Regional Jataí. Cada parcela continha 10 linhas do híbrido de milho SYN 7G17. Cada ensaio foi constituído de oito tratamentos estabelecidos em delineamento com blocos casualizados em esquema fatorial 2 x 4 mais um tratamento controle (sem aplicação de maturador), com quatro repetições. O primeiro fator corresponde a aplicação nos estádios V4 e V8 da cultura do milho e o segundo fator às subdoses de 3; 6; 9 e 12% de 475,2 g i.a. ha-1 de ethephon (Ensaio I), 216,0 g e.a. ha-1 de glyphosate (Ensaio II) e 15,0 g i.a. ha-1 de sulfometuron methyl (Ensaio III). Aos 20 e aos 36 dias após a semeadura, quando as plantas de milho se encontravam em V4 e V8, respectivamente, foram realizadas as aplicações dos maturadores. Os efeitos de fitotoxicidade foram perceptíveis em ambos os estádios aos 7, 14, 21, 28 e 42 dias após a aplicação apenas para o Ensaio III. Para glyphosate, o comprimento e diâmetro de espigas foram afetados para ambos os estádios. A cultura do milho é sensível a subdoses a partir de 0,45 g i.a. ha-1 de sulfometuron methyl em estádios de desenvolvimento V4 e V8. A produtividade de grãos foi menor apenas para as plantas submetidas às subdoses de sulfometuron methyl, com menos efeito quando a deriva ocorre no estádio de desenvolvimento V8 em comparação ao estádio V4.
72

Approches moléculaires et cellulaires des effets combinés du bisphénol A, du glyphosate et d’une toxine marine sur quatre modèles cellulaires humains / Molecular and cellular approaches to study the combined effects of bisphenol A, glyphosate and a marine toxin on four human cellular models

Laamari, Mariem 16 December 2016 (has links)
L’apparition de l’obésité et du cancer du sein est influencée par l’exposition aux polluants environnementaux. Ces polluants interfèrent avec le fonctionnement normal de l’organisme causant des modifications dans le comportement cellulaire. Ils peuvent agir chacun seul ou sous forme de cocktail. Dans ce contexte, nous avons choisi trois polluants dans notre projet : le bisphénol A (perturbateur endocrinien), le glyphosate (désherbant) et l’acide okadaïque (toxine marine). Nous avons étudié leur effet seul ou en cocktail sur les cellules de cancer du sein MCF7 et MDA-MB231, les cellules épithéliale mammaire humaine HME1 et les préadipocytes humain HWP. Dans une première partie, nous avons étudié leur effet sur la viabilité cellulaire. L’électrophorèse 2D couplée à MS/MALDI-TOF, le dosage de l’activité des protéines phosphatases ont été menés pour comprendre le mécanisme d’action des polluants sur la viabilité cellulaire. La partie suivante a porté sur la détection et la quantification des polluants dans le milieu de culture afin de déterminer leur voie d’action : extra ou intra cellulaire. Finalement, nous avons étudié l’effet des polluants sur le cycle de vie des adipocytes et la lipogenèse. Également, l’effet de sécrétome des HWP (+/-polluants) sur la viabilité cellulaire des cellules cancéreuses a été étudié. / The development of obesity and breast cancer is influenced by exposure to environmental pollutants. These pollutants interfere with the normal body function causing changes in cells behavior. They can act each alone or as a cocktail. In this context, we have chosen three pollutants in our project : bisphenol A (endocrin disruptor), glyphosate (herbicide), okadaic acid (marin toxine). We have studied their effect of alone or in combination in cellular models : human breast cancer cells MCF7 and MDA-MB 231, human mammary epithelial cells HME1 and human preadipocytes HWP. In the first part, we have studied the effect of pollutants on cells viability. 2D electrophoresis coupled to MS/MALDI-TOF, measurement of proteins phosphatase activity were conducted to understand pollutants action mechanism on cells viability. In the following part we detected and quantified pollutants in culture medium to determine their pathway of action : extra or intra cellular. Finally, we studied the effect of pollutants on adipocytes life cycle and lipogenesis. Also, effect of secretome from HWP (+/- pollutants) on cancer cells viability was studied.
73

Physical mapping of EPSPS gene copies in glyphosate resistant Italian ryegrass (Lolium perenne ssp. multiflorum)

Putta, Karthik January 1900 (has links)
Master of Science / Department of Agronomy / Randall S. Currie / Mithila Jugulam / Italian ryegrass (Lolium perenne L. ssp. multiflorum (Lam.) Husnot), one of the problem weeds of the US, evolved resistance to multiple herbicides including glyphosate due to selection in Arkansas (AR). Glyphosate is a 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor and amplification of EPSPS gene, the molecular target of glyphosate confers resistance to this herbicide in several weed species, including Italian ryegrass from AR. The objective of this study was to determine the expression of EPSPS gene and protein as well as distribution of EPSPS copies on the genome of glyphosate-resistant Italian ryegrass (ARR) using a known susceptible Italian ryegrass (ARS) from AR. EPSPS gene copies and expression of ARR and ARS were determined using quantitative PCR with appropriate endogenous controls. EPSPS protein expression was determined using Western blot analysis. Fluorescence in situ hybridization (FISH) was performed on somatic metaphase chromosomes to determine the location of EPSPS copies. Based on qPCR analysis, ARR plants showed a wide range of 12 to 118 EPSPS copies compared to a single copy in ARS. EPSPS gene expression correlated with the gene copy number in both ARR and ARS. Individuals with high EPSPS copies showed high protein expression in Western blot analysis. FISH analysis showed presence of brighter EPSPS signals, distributed randomly throughout the genome of ARR individuals compared to a faint signal in ARS plants. Random distribution of EPSPS copies was previously reported in glyphosate-resistant Palmer amaranth. Overall, the results of this study will help understand the origin and mechanism of EPSPS gene amplification in Italian ryegrass.
74

Impact sur l'environnement d'un herbicide non sélectif, le glyphosate : approche modélisée en conditions contrôlées et naturelles / Environmental impact of a non selective herbicide, the glyphosate : approach modelled in controlled and natural conditions

Al Rajab, Abdul Jabbar 29 June 2007 (has links)
Les principaux processus et facteurs qui influent sur le devenir du glyphosate dans les sols et le risque de contamination de la ressource en eau ont été étudiés. Son adsorption sur les sols est très rapide (Kf compris suivant le sol entre 16,6 à 34,5) et l’effet du pH sur ce processus a été confirmé : l’adsorption diminue quand le pH des sols augmente. Par contre, le glyphosate se désorbe difficilement et sa dégradation en conditions contrôlées ou naturelles est rapide, mais sa dynamique est très variable suivant l’activité biologique des sols. La dégradation conduit à la formation d’un métabolite, l’AMPA qui tend à s’accumuler dans le sol. L’expérimentation en colonnes de sol confirme la faible mobilité du glyphosate et de l’AMPA. Les résidus exportés par les percolats sur une période de 332 jours représentent moins de 0,28 % de la dose appliquée. Les propriétés hydrodynamique du sol et la pluviométrie rencontrée ont un effet important dans le lessivage des résidus. / The main processes and factors which influence glyphosate fate in soils and the risks of water resources contamination were studied. Its adsorption in the soils was very fast and intense (Kf between 16.6 to 34.5 depending on the soil) and the effect of pH on this process was confirmed: adsorption decreases when soil pH increased. In addition, glyphosate was slightly desorbed and its degradation in controlled or natural conditions was fast, but its kinetics was very variable according to the biological activity of the soils. Degradation led to the formation of the metabolite (AMPA), which tends to accumulate in the soil. The experimentation in columns of different soils confirmed the low mobility of the glyphosate and the AMPA. The residues exported by the leachates after more than 332 days represented less than 0.28% of the amount applied. The hydrodynamic properties of the soil and the pluviometry observed had a significant effect on the leaching of the residues.
75

development of novel efficient sensors for the recognitions of different water species – aluminium ions, potassium ions, atrazine and glyphosate / développement de nouveaux capteurs efficaces pour la reconnaissance de différentes espèces d'eau – ions aluminium, ions potassium, atrazine et glyphosate.

Nguyen, Hanh Linh 04 December 2019 (has links)
La conception, la synthèse et l’étude des propriétés photophysiques de sondes fluorescentes d’espèces moléculaires ou de cations présente beaucoup d’intérêt dans des domaines aussi divers que l’environnement et la biologie. En particulier, les cations polluants (cations d’aluminium, cations de potassium) et les résidus de pesticides (tels que le glyphosate ou l’atrazine) qui n’étant pas dégradés par le métabolisme, ils se retrouvent dans les eaux de boissons à des concentrations délétères pour l’environnement. Les méthodes analytiques actuelles telles que la spectroscopie d'absorption atomique, la spectroscopie de masse sont coûteuses et ne peuvent être utilisées que pour les déterminations à l'intérieur. Inversement, l'utilisation de la technique de fluorescence offre des avantages distincts en termes de sensibilité, de sélectivité et de développement potentiel d'appareils portables.Dans cette thèse, des sondes fluorescentes efficaces pour la détection de l'aluminium, du potassium, du glyphosate et de l'atrazine ont été ciblées. Pour l'aluminium, une nouvelle sonde hydrosoluble (PSSA) a été synthétisée, reconnaissant les cations d'aluminium sur la base du mécanisme d'amélioration de l'émission induisant une agrégation. Avec une limite de détection de 153 nM et une bonne propriété de sélectivité, le PSSA a également été intégré avec succès dans un système PDMS / verre afin de permettre l’utilisation d’un dispositif portable pour la détection de l’aluminium.Ensuite, deux sondes synthétisées différentes de notre laboratoire (Calix-Rhod-aza et DMAP-BARB) ont été considérées dans cette thèse. Ces sondes ont été développées pour la détection de potassium et d'atrazine, respectivement. Pour les deux molécules, la photophysique et la complexation vis-à-vis d'espèces ciblées ont été étudiées, et deux configurations différentes de microfluidique capillaire en PTFE ont été réalisées pour leur détection, avec des limites de détection très satisfaisantes (qui bien conformes à la gamme des normes réglementaires).Enfin, des efforts ont été consacrés à la conception et à la synthèse de nouveaux capteurs pour le glyphosate. Quatre sondes différentes ont été conçues (GlyP-a, GlyP-b, GlyP-c, GlyP-d). GlyP-a a été faite, alors que les autres étaient à deux pas de la réalisation. En effet, ce projet est toujours en cours dans notre laboratoire, en prenant les résultats préliminaires de ce travail. / The design, synthesis and photophysical studies of fluorescent sensors of neutral molecules or cations are of great interest in environment and biology. In particular, metal-based pollutants (aluminium cations, potassium cations) and pesticide residues (such as glyphosate or atrazine) which are not degraded by the metabolism can be found in drinking water at harmful concentrations to the environment. Actual analytical methods such as atomic absorption spectroscopy, mass spectroscopy are expensive and can only be used for indoor determinations. Conversely, the use of fluorescence technique offers distinct advantages in terms of sensitivity, selectivity with a potential development of portable devices.In this thesis, efficient fluorescent probes for the sensing of aluminium, potassium, glyphosate and atrazine were targeted. For aluminium, a novel water-soluble probe (PSSA) was synthesized, which recognize aluminium cations based on aggregation-induce emission enhancement mechanism. With a detection limit of 153 nM and good selectivity property, PSSA was also successfully incorporated onto a PDMS/glass system for enabling a portable device for aluminium detection.Next, two different synthesized probes from our laboratory (Calix-Rhod-aza and DMAP-BARB) were considered in this thesis. These probes were developed for potassium and atrazine sensing, respectively. For both molecules, the photophysical and complexation towards targeted species were studied, and two different PTFE capillary microfluidics set-ups were realized for their detection, with highly satisfactorily detection limits (well in accordance with the range of the regulation standards).Finally, efforts were given on the design and synthesis of new sensors for glyphosate. Four different probes were designed (GlyP-a, GlyP-b, GlyP-c, GlyP-d). GlyP-a has been made, while the others were just one step away from realization. Indeed, this project is still under progress in our laboratory, taking the preliminary results from this work.
76

Microbial Community Structure in Soils Amended With Glyphosate Tolerant Soybean Residue

Nye, Mark Edward 18 August 2014 (has links)
No description available.
77

Converting Turf to a Xeriscape Landscape: How To Eliminate a Bermudagrass Lawn Using Glyphosate

Kelly, Jack 09 1900 (has links)
2 pp. / The most difficult part of conversion from a lawn to a low water (xeriscape) landscape is the removal of a lawn. By removing a Bermuda grass lawn, it is estimated that water savings of 50 -75% is possible. Potential water savings comes from the fact that water is applied to a limited amount of total yard space, compared to the greater water needs of a continuous grass-covered area. Also, by planting low water use plants, less maintenance is required and substantial cost savings can be realized. Turf removal and subsequent weed suppression is achievable using readily available herbicides.
78

Desenvolvimento e validação de metodologia para determinação multirresíduo de glifosato e AMPA via CG-EM em amostras ambientais / Development and validation of methodology for multiresidue determination of glyphosate and AMPA via GC-MS in environmental samples

Benetti, Fernanda 13 April 2011 (has links)
O glifosato é o herbicida mais usado em todo o mundo. Sendo assim, é necessário que se tenham programas de monitoramento do seu uso, para garantir o bem estar da lavoura e da população. O seu metabólito principal é o ácido aminometilfosfônico (AMPA) que apesar de possuir baixa toxicidade, é mais persistente que o glifosato. O presente trabalho teve como objetivo desenvolver uma metodologia de análise para o glifosato e o AMPA por cromatografia gasosa acoplada à espectrometria de massas (CG/EM), a fim de avaliar possíveis contaminações em amostras ambientais nas imediações do Rio Monjolinho, em São Carlos. Para a faixa estudada (1,0 ug L-1 a 500 ug L-1, os limites de detecção e quantificação para o AMPA foram de 0,15 e 0,45 ug L-1 e para o glifosato, 0,67 e 2,02 ug L-1. As recuperações em água variaram entre 96,2 e 121% e para solo 70,1 a 119%. O método proposto apresentou boa linearidade, exatidão, seletividade e sensibilidade. A robustez foi avaliada de acordo com o teste de Youden. O procedimento de extração foi baseado em reações ácido-base e realizou-se etapa de clean-up para água e sedimento. Para os pontos amostrados, houve resíduo de AMPA em dois pontos (4,19 e 6,22 ug L-1). Os resultados encontrados para DBO foram altos, estando acima do limite estabelecido para um corpo d\'água Classe 3, de acordo com a CONAMA 357. Isso pode ter ocorrido devido à grande quantidade de esgoto despejado no leito do rio. Os valores de nitrogênio e fósforo também estão elevados, o que indica uma alta eutrofização do leito do rio. Vale ressaltar a necessidade de se ter uma legislação que estabeleça um limite máximo permitido para o AMPA, visto que ele é mais persistente no ambiente do que o glifosato. / The glyphosate is the most widely used herbicide worldwide. Therefore, it is necessary to have programs for monitoring their use to ensure the welfare of the farming and population. Its main metabolite is the acid aminomethylphosphonic (AMPA) that despite having low toxicity, is more persistent than glyphosate. This study aimed to develop a methodology for analyzing glyphosate and AMPA by gas chromatography coupled to mass spectrometry (GC/MS) in order to assess possible contamination of samples environment in the vicinity of Monjolinho River in São Carlos. In the range studied (1.0 ug L-1 to 500 ug L-1, limits of detection and quantification were 0.15 and 0.45 ug L-1 for AMPA and 0.67 and 2.02 ug L-1 for glyphosate. The recoveries in water varied between 96.2 and 121% and for soil from 70.1 to 119%. The proposed method showed good linearity, accuracy, selectivity and sensitivity. The robustness was evaluated according to the Youden test. The extraction procedure was based on acid-base reactions and included a clean-up step for water and sediment. For the sampling sites, it was determined residual AMPA at two points (4.19 and 6.22 ug L-1). The results for BOD were high, being above the limit set for a waterbody Class 3, according to CONAMA 357. This may be due to large amount of sewage dumped into the river bed. The values of nitrogen and phosphorus are also high, which indicates a high eutrophication of the bed river. It is worth emphasizing the need of having a legislation that establishes a maximum allowed value for AMPA, whereas it is more persistent in environment than glyphosate.
79

Estudo da mobilidade do glifosato utilizado como capina química em um programa de recuperação de mata ciliar /

Silva Junior, Eurípedes. January 2010 (has links)
Resumo: A prática da utilização de pesticidas para controle ou eliminação de pragas é uma atividade de grande ocorrência e um dos fatores de elevado potencial de contaminação de ambientes naturais. Os herbicidas, um tipo particular de pesticidas, são utilizados principalmente em práticas agronômicas como por exemplo, a capina química, a fim de eliminar e ou controlar certas espécies de plantas as quais prejudicam o desenvolvimento e cultivo de culturas. A capina química é um método rápido, economicamente viável e ideal para ser utilizado em locais de relevo acidentado, onde a supressão mecânica ou manual é dificultada. Atualmente, o glifosato é o herbicida mais empregado mundialmente, para o controle e eliminação de plantas daninhas. Quando metabolizado por microrganismos origina, por uma de suas rotas de degradação o ácido aminometilfosfônico (AMPA), metabólito mais persistente no ambiente e em alguns animais do que o glifosato, entretanto, apresenta toxicidade aguda (LD50 = 8.300 kg mg-1) mais baixa do que o glifosato (LD50 = 4.230 kg mg-1). O presente trabalho teve como objetivo avaliar o comportamento de glifosato no ambiente mediante estudo de mobilidade após utilização do glifosato como capina química em um Programa de Recuperação de Mata Ciliar (PRMC). Para isso, concentrações de glifosato e AMPA foram determinadas, bem como parâmetros físico químicos que poderiam influenciar a mobilidade dos mesmos, nas matrizes de solo, sedimento e água superficial. O PRMC é composto de vários projetos de caráter ambiental e tem como objetivo recuperar a maior área possível de mata ciliar no Estado de São Paulo. Este trabalho foi realizado no município de Paraibuna - SP na microbacia do Ribeirão Fartura sendo utilizado como estudo preliminar a fim de garantir a utilização ambientalmente segura de glifosato. O estudo verificou que as características... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of pesticides for controlling or pests elimination is a very common practice and one factor of high potential for contamination of natural environments. Herbicides are a particular type of pesticides that are used mainly in agronomic practices in order to eliminate or control certain plant species which affect the development and cultivation of crops.The chemical weeding control is a method in which an herbicide is used in areas of rugged terrain that makes difficult the elimination of weed by mechanical or manual procedure. Currently, the Glyphosate, N-(phosphonomethyl) glycine, is the herbicide most used worldwide to control and eliminate weeds. When metabolized by microorganisms leads by one of its routes degradation aminomethylphosphonic acid (AMPA), a metabolite more persistent in the environment and in some animals than glyphosate, however, acute toxicity (LD50 = 8.300 kg mg-1) lower than glyphosate (LD50 = 4.230 kg mg-1). This work intends to evaluate the performance of glyphosate on the environment through the study of mobility after use of chemical weed control in glyphosate as a Recovery Program Riparian Forest (PRMC). For this purpose, concentrations of glyphosate and AMPA were determined, as well as physical and chemical parameters that could influence the mobility of these volumes in arrays of soil, sediment and surface water. The PRMC program is composed of several environmental projects that aim to recover the largest possible area of riparian vegetation at São Paulo state. This work was conducted at Paraibuna city - SP in the Ribeirão Fartura catchment as a preliminary study to ensure the environmentally safe use of glyphosate. This work concluded that the physico-chemical properties of soil influence in the availability of the herbicide and its metabolite in the environment. During all the monitoring period, no residues of glyphosate were detected in any sample... (Complete abstract click electronic access below) / Orientador: Ademir dos Santos / Coorientador: Sonia dos Santos / Banca: Francismário Ferreira dos Santos / Banca: Luciana Camargo de Oliveira / Mestre
80

Building the case for residential herbicide exposure assessments in Iowa communities

Lebeck, Mark Gordon A. 01 May 2013 (has links)
Pesticide use has steadily increased in the United States and throughout the world since the development of more highly effective agrichemicals dating back to World War II. While many of these compounds are considered to have little to no detrimental environmental impact with relatively low toxicity and potential for causing adverse health effects in humans, many recent studies examining the toxicological properties and health outcomes associated with exposure to a variety of pesticides suggest otherwise. In heavily agricultural-based regions, particularly where row crops predominate, large amounts of herbicides and insecticides are used in activities involving pest management annually. The high volume of chemical applications to agricultural fields is cause for concern due their potential for leaching into soil following application events and subsequent transport to water systems. Pesticide-contaminated ground and surface water systems may pose a threat to public health by the presence and persistent elevated concentrations of chemicals found in both public and private drinking water. The herbicides atrazine and glyphosate are and have been the two most heavily applied pesticides in the U.S. Many studies have examined occupational exposures to these compounds and related health outcomes, yet very few have evaluated low-level exposures to more susceptible rural populations. This thesis will examine state-of-the- science behind atrazine and glyphosate, evaluate drinking water quality measurements in relation to herbicide usage estimates in Iowa, and finally, make recommendations for future atrazine and glyphosate exposure assessment studies in rural Iowa populations.

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