Dissertations / Theses: 'Pestides'

1

Devilliers, Esther. "Modélisation micro-économétrique des choix de pratiques de production et des utilisations d'intrants chimiques des agriculteurs : une approche par les fonctions de production latentes." Thesis, Rennes, Agrocampus Ouest, 2021. http://www.theses.fr/2021NSARE058.

Full text

Abstract:

La notion d’itinéraire technique est une notion agronomique qui nous permet d’appréhender l’imbrication entre les rendements objectifs et les niveaux d’utilisation d’intrants associés. Dès lors, on peut admettre qu’à différents types d’itinéraires techniques correspondent différentes fonctions de production. Modéliser ces différentes fonctions est une des clés pour mieux comprendre la dépendance de certaines pratiques culturales aux pesticides et de ce fait constitue un enjeu majeur pour concevoir les futures politiques publiques.Intégrer cette notion d’itinéraire technique nécessite de tenir compte de l’interdépendance entre les choix de ces pratiques, leur rendement et les utilisations associées. Pour ce faire, on considère des modèles de changement de régime endogène qui permettent de contrôler des biais de sélection. Lorsque ces pratiques sont inobservées, on définit la séquence de choix comme processus Markovien.Le modèle résultant nous permet de recouvrir les pratiques culturales, leurs niveaux de rendement et d’utilisation d’intrants ainsi que la dynamique de choix des dites pratiques. Lorsque ces pratiques sont observées, on décide de considérer un modèle primal afin de pouvoir vérifier le rôle différencié des pesticides et évaluer l’effet des politiques publiques conjointement sur les rendements et les niveaux d’utilisation d’intrants chimiques.En bref, cette thèse vise à donner des outils pour évaluer au mieux les effets des politiques agro-environnementales sur les utilisations de pesticides, les rendements et mes choix de pratiques culturales des agriculteurs
Cropping management practices is an agronomic notion grasping the interdependence between targeted yield and input use levels. Subsequently, one can legitimately assume that different cropping management practices are associated to different production functions. To better understand pesticide dependence – a key point to encourage more sustainable practices – one have to consider modelling cropping management practices specific production functions.Because of the inherent interdependence between those practices and their associeted yield and input use levels, we need to consider endogenous regime switching models.When unobserved, the sequence of cropping management practices choices is considered as a Markovian process. From this modelling framework we can derive the cropping management choices, their dynamics, their associated yield and input use levels. When observed, we consider primal production functions to see how yield responds differently to input uses based on the different cropping management practices. Thus, we can assess jointly the effect of a public policy on input use and yield levels.In a nutshell, in this PhD we are aiming at giving some tools to evaluate the differentiated effect of agri-environmental public policies on production choies and on the associated yield and input use levels

APA, Harvard, Vancouver, ISO, and other styles

2

Woida, Angela E. "Pesticides." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/292163.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Lam, Ding. "An overview of pesticide consumption and management in Hong Kong /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22264401.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Pieters, Barry Johan. "Daphnid population responses to pesticides." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/45997.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Rolland, Olivier. "Toxicologie des pesticides systémiques organophosphorés." Paris 5, 1988. http://www.theses.fr/1988PA05P034.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Solís, Sánchez Cristina. "Geography of pesticide exposure in the Lower Valley (El Paso County, Texas)." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Smith, Edward James. "The fate of pesticides on plants." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488746.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Khor, Jen Nee. "Oxidation of pesticides in photocatalytic reactors." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403398.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Kah, MeÌlanie. "Behaviour of ionisable pesticides in soils." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440684.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Quivet, Étienne. "Analyse du comportement environnemental de pesticides." Lyon 1, 2004. http://www.theses.fr/2004LYO10278.

Full text

Abstract:

La photodégradation de l'imazapyr et de l'imazamox, deux herbicides de la famille des imidazolinones, a été étudiée en solution aqueuse sous rayonnement UV. Les résultats obtenus ont permis de proposer des schémas de dégradation de ces herbicides. Les cinétiques de dégradation des pesticides d'une part, d'apparition et de disparition des principaux photoproduits d'autre part, ont été suivies par chromatographie liquide couplée à un détecteur à barrettes de diodes (LC-DAD). Après une étape de pré-concentration sur phase solide (SPE), la caractérisation des photoproduits a été réalisée par chromatographie liquide couplée à un spectromètre de masse (LC-MS) et par spectrométrie de masse haute résolution (HRMS). Les pesticides sont stables à l'obscurité mais se dégradent sous irradiation selon une cinétique de premier ordre, l'imazamox étant deux fois plus stable que l'imazapyr. Ces pesticides conduisent en présence d'ions métalliques à des interactions de complexation fortes de type chélate. Une structure cristalline entre l'imazapyr et le cuivre [Cu(Himz)2(H2O)2] a été mise en évidence par diffraction X. Une étude chimiométrique a permis d'évaluer l'influence sur la dégradation de cations métalliques tels que le cuivre ou le calcium, d'anions associés tels que les ions nitrate ou chlorure, et du rapport molaire pesticide/ion métallique, ainsi que les éventuelles interactions entre ces paramètres. Les cinétiques de dégradation et d'apparition des pesticides et des principaux photoproduits sont ralenties en présence d'ions métalliques (Cu2+ > Ca2+). En effet, la complexation tend à stabiliser les molécules. Au contraire, la présence d'ions nitrate augmente la dégradation par suite de formation de radicaux hydroxyle sous irradiation UV

APA, Harvard, Vancouver, ISO, and other styles

11

Papa, Kassim. "Variabilité de l'effet mitochondrial des pesticides." Aix-Marseille 2, 2007. http://www.theses.fr/2007AIX20662.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Lohner, Timothy W. "Effects of pH, temperature, and sediment on the aquatic fate and toxicity of selected pesticides /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487332636474975.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Zheng, Shan-qiang. "Comportement de divers pesticides dans les sols. Application en milieux tropical et méditerranéen." Montpellier 1, 1994. http://www.theses.fr/1994MON13504.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Bouya, Houceine. "Dégradation par voie électrochimique de nitro-benzaldehyde et cyperméthrine et étude cinétique d’oxydation atmosphérique du bupirimate et nitrobenzaldehyde." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS018/document.

Full text

Abstract:

Cette thèse porte sur l’étude des composés organiques semi-volatils, notamment les pesticides et les composés nitro-aromatiques dans les deux compartiments l’eau et l’atmosphère. La première partie de ce travail concerne l'optimisation des différents paramètres expérimentaux (concentration initiale des composés, concentration de l’électrolyte support, température et la densité de courant imposé) de la dégradation de la cypermethrine et du 2-Nitrobenzaldehyde (2-NBA) par oxydation direct moyennant les électrodes de l'oxyde d'étain (SnO2) et le diamant dopé au bore (DDB). Cette dégradation a été suivie par les analyses de la demande chimique en oxygène (DCO) et la chromatographie en phase gazeuse. Les résultats obtenus montrent que le taux de minéralisation dépasse 80 % pour le cypermethrine en utilisant le DDB. La deuxième partie est consacrée à l'étude de la réactivité du bupirimate vis-à-vis de l’ozone et les radicaux OH• en phase hétérogène. Les résultats obtenus montrent que les valeurs de la constante cinétique pour la réaction du bupirimate avec les radicaux OH• et l’ozone sont respectivement de l’ordre de 1,06 x 10-12 et 5,4 x 10-20 (cm3 molecule-1 s-1). La durée de vie du bupirimate est de plusieurs mois par rapport à l'ozone et de quelques jours par rapport aux radicaux OH•. Les spectres UV et la réactivité homogène vis-à-vis des radicaux OH• du 2-Nitrobenzaldehyde (2-NBA) a été déterminé en phase gazeuse. Les études cinétiques ont été réalisées dans une chambre atmosphérique couplée à un spectromètre IR. Les résultats obtenus montrent que le 2-NBA est sensibles à la photolyse dans l’atmosphère et que sa réactivité vis-à-vis des radicaux OH• est non négligeable. En effet, la durée de vie atmosphérique de ce composé est relativement courte. Elle varie de quelques minutes à quelques heures. Le 2-NBA est donc non persistant dans l’atmosphère
This thesis focused on the study of semi-volatile organic compounds (SVOC), including pesticides and nitro-aromatics compounds in the two compartments, water and atmosphere. The first part of this work concerns the optimization of the different experimental parameters in order to mineralize two compounds (cypermethrin and of 2-Nitrobenzaldehyd), those parameters are initial concentration of compounds, concentration of the electrolyte support, temperature and the density of the current imposed. This mineralization has been done by a direct oxidation through the electrodes of the tin oxide (SnO2) and Boron Doped Diamond (BDD). The degradation process has been followed by the DCO analyzes and the gas chromatography. It has been shown that the rate of mineralization exceeds 80 % for the cypermethrine compound using BDD electrode. The second part is devoted to study the reactivity of bupirimate in heterogeneous phase using ozone and OH radicals as oxidant. The obtained results show that the rate constant values of the analyte are (1,06 ± 0,87) x 10-12 and (5,4 ± 0,3) x 10-20 (cm3 molecule-1 s-1) relative to heterogeneous OH-oxidation and O3, respectively. Such values implicate tropospheric life-times that vary from a few days to several months, meaning that these compounds are relatively persistent and may be transported to regions far from their point of application. The UV-absorption spectra and homogeneous OH-reactivity of 2-Nitrobenzaldehyde compound in the gas phase are investigated. The kinetic studies have been carried out in an atmospheric chamber coupled to an IR spectrometer. The results obtained indicate that the compound studied is susceptible to photolysis in the atmosphere and he exhibit strong reactivity towards OH-radicals. Generally speaking, the atmospheric life-time of this compound is relatively short, in the order of a few minutes to hours and he is non-persistent. Rate constants present a slight variation with the temperature

APA, Harvard, Vancouver, ISO, and other styles

15

Fragoeiro, Silvia. "Use of fungi in bioremediation of pesticides." Thesis, Cranfield University, 2005. http://hdl.handle.net/1826/906.

Full text

Abstract:

Eight isolates (7 species) of white rot fungi were grown on soil extract agar amended with 0, 5 10 and 20 mg l- simazine, trifluralin and dieldrin, individually and as a mixture, under two different water regimes (-0.7 and -2.8 MPa water potential). The best isolates were T.versicolor (R26 and R101) and P.ostreatus, exhibiting good tolerance to the pesticides and water stress and the ability to degrade lignin and produce laccase in the presence of these pesticides. As a result, the activity of those three isolates plus Phanerochaete chrysosporium (well described for its bioremediation potential) was examined in soil extract broth in relation to differential degradation of the pesticide mixture at different concentrations (0-30 mg l-1) under different osmotic stress levels (-0.7 and -2.8 MPa). Enzyme production, relevant to P and N release (phosphomonoesterase, protease), carbon cycling (β-glucosidase, cellulase) and laccase, involved in lignin degradation was quantified. The results suggested that the test isolates have the ability to degrade different groups of pesticides, supported by the capacity for expression of a range of extracellular enzymes at both -0.7 and -2.8 MPa water potential. P.chrysosporium and T.versicolor R101, were able to degrade this mixture of pesticides independently of laccase activity, whereas P.ostreatus and T.versicolor R26 showed higher production of this enzyme. Complete degradation of dieldrin and trifluralin was observed, while about 80% of the simazine was degraded regardless of osmotic stress treatment in a nutritionally poor soil extract broth. The results with toxicity test (Toxalert®10), suggested the pesticides were metabolised. Therefore the capacity for the degradation of high concentrations of mixtures of pesticides and the production of a range of enzymes, even under osmotic stress, suggested potential applications in soil. Subsequently, microcosm studies of soil artificially contaminated with a mixture of pesticides (simazine, trifluralin and dieldrin, 5 and 10 mg kg soil-1) inoculated with P.ostreatus, T.versicolor R26 and P.chrysosporium, grown on wood chips and spent mushroom compost (SMC) were examined for biodegradation capacity at 15ºC. The three test isolates successfully grew and produced extracellular enzymes in soil. Respiratory activity was enhanced in soil inoculated with the test isolates, and was generally higher in the presence of the pesticide mixture, which suggested increased ii mineralization. Cellulase and dehydrogenase was also higher in inoculated soil than in the control especially after 12 weeks incubation. Laccase was produced at very high levels, only when T.versicolor R26 and P.ostreatus were present. Greatest degradation for the three pesticides was achieved by T.versicolor R26, after 6 weeks with degradation rates for simazine, trifluralin and dieldrin 46, 57, and 51% higher than in natural soil. And by P.chrysosporium, after 12 weeks, with degradation rates 58, 74, and 70% higher than the control. The amendment of soil with SMC also improved pesticide degradation (17, 49 and 76% increase in degradation of simazine, trifluralin and dieldrin compared with the control).

APA, Harvard, Vancouver, ISO, and other styles

16

Cravey, Suzanne Perritt. "Are pesticides a factor in bird declines? /." Connect to this title online, 2005. http://www.orwapif.org/pdf/pesticides%5Fbirds.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Termtanun, Mutsee. "Photocatalytic degradation of pesticides using TiO2 nanoparticles." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13827/.

Full text

Abstract:

The problem of water pollution has been an environmental concern for many years. Numerous researchers are looking for an effective method to solve this issue. Heterogeneous photocatalysis, using a semiconductor as a catalyst, is a promising method for the destruction of water polluting pesticides. This method has been called the Advanced Oxidation Process (AOP) which is one of the techniques for water treatment. Titanium dioxide (TiO2) is the most widely accepted photocatalyst because it is non-toxic, stable to photocorrosion, low cost and can potentially work using sunlight rather than artificial sources of light. When titanium dioxide is illuminated by UV radiation, the absorption of photons of energy is then equal to or greater than its band gap width. This artefact leads to the formation of conduction-band electrons and valence-band holes on the surface of TiO2, which yield hydroxyl radicals, the primary oxidising species needed for the photocatalytic degradation of pollutants. Supercritical water hydrothermal synthesis (ScWHS) is one of novel approaches for nanoparticle manufacture which involves the mixing of an aqueous metal salt stream with a supercritical water stream to produce nano-sized metal oxide particles. The engineering design for the mixing of these two fluids is critical and a novel nozzle reactor has been developed at the University of Nottingham that can produce high quality particles with an excellent control over particle size and particle size distribution. By application of this technique, titanium dioxide (TiO2), in nanoparticle form, was produced and used for the photocatalytic treatment of wastewater. In this thesis, the photocatalytic degradation of the three pesticides - isoproturon, simazine and propazine - was measured using 3 different types of reactors: thin film fixed bed reactor (TFFBR), a stirred reactor, and a fluidised bed photoreactor. Various conditions were used: for example without UVC and UVA illumination, with commercial TiO2, with the synthesised TiO2, without any photocatalyst, low concentration, high concentration, and at different TiO2 concentrations. The optimum TiO2 concentration for the treatment of the three chosen pesticides was equal to 5 g litre-1. The efficiency in decreasing the pesticides concentration of the synthesised TiO2 (from ScWHS technique) with all three types of reactors was lower than that of the commercial titanium dioxide (P-25 TiO2). The fluidised bed reactor appeared to give the highest performance amongst three reactors.

APA, Harvard, Vancouver, ISO, and other styles

18

Odon, Akanimo P. "Effect of Pesticides on Non -Target Species." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531707.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Robinson, Roger Kevin. "Computational study of carbamate and organophosphate pesticides." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433451.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Fitzpatrick, Lisa Jane. "Extraction and photolysis of pesticides on soil." Thesis, Northumbria University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325378.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Bhandal, Narotam Singh. "Arthropod chloride channels as targets for pesticides." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335651.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Mackay, Neil. "Modelling the fate of pesticides in soil." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Fogg, Paul. "Fate and behaviour of pesticides in biobeds." Thesis, Cranfield University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405625.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Aguilar, Carolina. "Pesticides and pesticide combinations on brain neurochemistry." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34697.

Full text

Abstract:

Pesticides have been suggested to play a role in the development of many neurodegerative diseases including Parkinson's disease and Alzheimer's disease. Additionally, it has been suggested that exposure to pesticides and other environmental chemicals during the early stages of life could result in an increased vulnerability to such substances that could lead to neurotoxicity and degeneration late in life. We hypothesized that exposure to mixtures of certain pesticides could change neurotransmitter levels and cellular oxidative stress and that this would be greater in mice exposed early and later in life than mice exposed only as adults. We studied the effects of permethrin (PR) (a pyrethroid type I) and endosulfan (EN) (an organochlorine) on the levels of catecholamines, indolamines, acetylcholinesterase, lipid peroxidation and α-synuclein in the brain of mice. These pesticides have different structures but both are known to modify the kinetics of voltage-sensitive ion channels and calcium ion flux/homeostasis that could affect the release of several neurotransmitters. The study consisted of two experiments: In the first experiment, adult C57Bl/6 mice (7-9 months old) were injected, intraperitoneally, with the following treatments: EN 4.3, 2.15 mg/kg; PR 150, 15 mg/kg and their mixtures EN 4.3 + PR 150 and EN 2.15 + PR 15 mg/kg. Mice were sacrificed 24 hrs after the last injection. In the second experiment, doses consisted of EN 0.7, 1.4 mg/kg, PR 1.5, 15 mg/kg and their mixtures EN 0.7 + PR 1.5 mg/kg and EN 1.4 + PR 15 mg/kg were given to juvenile mice intraperitoneally daily during a period of two weeks from postnatal day 5 to 19. Mice were then, left undisturbed with their dams. Re-challenge was performed when mice were 7-9 months old and dosages of EN 4.3, 2.15 mg/kg, PR 150, 15 mg/kg and their mixtures, EN 4.3 + PR 150 and EN 2.15 + PR 15 mg/kg were given intraperitoneally every other day during a period of two weeks to match the treatments when pesticide exposure was only as adults. Mice were sacrificed 24 hrs after the last injection.

The corpora striatum was extracted and analyzed by HPLC for catecholamines (dopamine, DOPAC, homovalinic acid and norepinephrine) and indolamines (serotonin and 5-HIAA). In general low doses of permethrin and endosulfan alone and in combination (EN 2.15 + PR 15 mg/kg) altered the levels of catecholamines and indolamines in both studies with adult mice and mice dosed as juveniles and re-challenged as adults. Catecholamine and indolamines levels were affected to a greater extent in the adult mice than in mice dosed as juveniles and re-challenged as adults, when compared to controls.

Acetylcholinesterase was increased under both exposure situations but again adult mice seemed to be more affected than mice dosed as juveniles and re-challenged as adults.

Because reactive oxygen species have been implicated in the development of Parkinson's disease, and are known to cause degradation of certain neurotransmitters, we monitored the levels of lipid peroxides in brain cortex as an indicator of free radical tissue damage. The peroxide levels were measured by thiobarbituric acid reactive products (TBARS). Increased levels of lipid peroxides were significant in the low dose treatment groups of the adult study. However, there seemed to be a pattern between the levels of dopamine and DOPAC in the striatum and the levels of peroxidation in cortex. The presence of dopamine metabolites appeared to be related to high levels of peroxidation within the basal ganglia and up-regulation of proteins such as α-synuclein. Western blots of α-synuclein in both experiments of the study showed intense double and triple bands that corresponded to aggregated α-synuclein. In general, when compared with controls, mice dosed as juveniles and re-challenged as adults did not alter the above parameters as much as mice dosed only as adults. Instead, the mice first dosed as juveniles seemed to develop an adaptation response to the later exposure of these pesticides.

Taking all these results into account, early exposure and re-challenge with permethrin and endosulfan in this study appeared to induce a protective response against neurochemical changes in the brain of these mice. In addition, low doses of these pesticides and the low dose combination mixture seem to exert an effect on the parameters studied.

Therefore, exposure to pesticides such as endosulfan and permethrin and their combinations could make a contribution towards the initiation or aggravation of biochemical neurodegenerative diseases such as Parkinson's and Alzheimer's diseases.

Master of Science

APA, Harvard, Vancouver, ISO, and other styles

25

Brimecombe, Rory Dennis. "Voltammetric analysis of pesticides and their degradation." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1015724.

Full text

Abstract:

Amitraz is a formamide acaricide used predominantly in the control of ectoparasites in livestock and honeybees. Amitraz hydrolysis is rapid and occurs under acidic conditions, exposure to sunlight and biodegradation by microorganisms. The main hydrolysis product of amitraz, 2,4-dimethylaniline, is recalcitrant in the environment and toxic to humans. An electrochemical method for the determination of total amitraz residues and its final breakdown product, 2,4-dimethylaniline, in spent cattle dip, is presented. Cyclic voltammetry at a glassy carbon electrode showed the irreversible oxidation of amitraz and 2,4-dimethylaniline. A limit of detection in the range of 8.5 x 10⁻⁸ M for amitraz and 2 x 10⁻⁸ M for 2,4-dimethylaniline was determined using differential pulse voltammetry. Feasibility studies in which the effect of supporting electrolyte type and pH had on electroanalysis of amitraz and its degradants, showed that pH affects current response as well as the potential at which amitraz and its degradants are oxidised. Britton-Robinson buffer was found to be the most suitable supporting electrolyte for detection of amitraz and its degradants in terms of sensitivity and reproducibility. Studies performed using environmental samples showed that the sensitivity and reproducibility of amitraz and 2,4-dimethylaniline analyses in spent cattle dip were comparable to analyses of amitraz and 2,4-dimethylaniline performed in Britton-Robinson buffer. In addition, the feasibility qf measuring amitraz and 2,4-dimethylaniline in environmental samples was assessed and compared to amitraz and 2,4-dimethylaniline analyses in Britton-Robinson buffer. Amitraz and 2,4-dimethylaniline were readily detectable in milk and honey. Furthermore, it was elucidated that 2,4-dimethylaniline can be metabolised to 3-methylcatechol by Pseudomonas species and the proposed breakdown pathway is presented. The biological degradation of amitraz and subsequent formation of 2,4-dimethylaniline was readily monitored in spent cattle dip. The breakdown of amitraz to 2,4-dimethylaniline and then to 3-MC was monitored using cyclic voltammetry.

APA, Harvard, Vancouver, ISO, and other styles

26

Наземцева, Ярослава Олександрівна, Ярослава Александровна Наземцева, and Yaroslava Oleksandrivna Nazemtseva. "Human and environmental risks of obsolete pesticides." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33529.

Full text

Abstract:

Pesticides have been used worldwide in agriculture to fight pests, to increase output, and control tropical diseases. But when pesticides can no longer be used for their intended purpose (for instance, due to deterioration or age) they become obsolete. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33529

APA, Harvard, Vancouver, ISO, and other styles

27

Zhu, Danyun. "Determination of Residential-Use Turf Pesticides in Surface and Ground Water by HPLC/DAD." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/ZhuD2003.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Schmitt, Philippe. "Potentiels de l'électrophorèse capillaire dans l'analyse des pesticides et des substances humiques : application à l'étude des interactions pesticides - substances humiques." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL117N.

Full text

Abstract:

Différentes méthodes électrophorétiques ont été développées pour l'analyse de pesticides et de substances humiques. En électrophorèse capillaire de zone (CZE), des herbicides cationiques (s-triazines) et/ou anioniques (acides phénoxyacétiques) peuvent être séparés aisément avec une limite de détection de l'ordre de 10 g/l. La CZE est également efficace dans l'analyse du comportement électrophorétique de mélanges complexes de polyélectrolytes anioniques tels que les substances humiques. Un exemple d'application de la CZE est donné dans l'analyse des métabolites hydroxyles de l'atrazine lors de processus photochimiques en présence de substances humiques dissoutes. L’addition dans le tampon de séparation de différentes cyclodextrines substituées permet la séparation d'énantiomères de pesticides racémiques. L’utilisation de la CZE dans l'analyse d'échantillons réels est démontrée dans le suivi de la dégradation sélective d'un mélange racémique de dichlorprop, après son application aux champs. Les énantiomères de pesticides neutres (organophosphorés, DDT, DDD, DDE, acétamides, ester d'acides phénoxyacétiques) sont séparés en utilisant l'électrophorèse capillaire micellaire (MECC) avec addition de cyclodextrines. L’addition dans le tampon de séparation de substances organiques (ou inorganiques) à réactions spécifiques avec les échantillons permet d'orienter et d'optimiser les séparations ; le capillaire devient un réacteur. Cette propriété est utilisée dans la technique d'électrophorèse capillaire d'affinité (ACE) qui a été adaptée pour la mesure simultanée des états de liaison entre quatre s-triazines et des acides phénoliques (addition des ligands dans le tampon de séparation). L’adsorption des mêmes herbicides à des substances humiques est modélisée d'une manière similaire qu'en électrophorèse capillaire micellaire (MECC), démontrant de surcroit les propriétés micellaires des substances humiques ; une concentration micellaire critique peut être définie pour les substances humiques (micelles chargées). De cette manière les coefficients de partage de s-triazines entre la phase aqueuse et différentes phases humiques dissoutes peuvent être déterminés rapidement et simultanément

APA, Harvard, Vancouver, ISO, and other styles

29

Pinkham, Wade A. "A Lateral Field Excited Acoustic Wave Pesticide Sensor." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/PinkhamWA2007.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Miranda, Jamilette. "Neurotoxicity after poisonings with organophosphate pesticides in Nicaragua /." Stockholm : Arbetslivsinstitutet, 2003. http://diss.kib.ki.se/2003/91-7045-668-2/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Mazlan, Norida. "Pesticides and food safety for Malaysian fresh vegetables." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435436.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Nisar, Rizwan. "Common pesticides and the development of Parkinson's disease." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1079.

Full text

Abstract:

Parkinson’s disease (PD) is an age-related neurodegenerative disorder, characterised by progressive degeneration of dopaminergic neurons in the substantia nigra, with the formation of α-synuclein rich, intracytoplasmic Lewy bodies. Several genetic and environmental factors, including pesticides are linked with sporadic PD. The aim of this study was to investigate the effect of selected pesticides on dopaminergic neuroblastoma SH-SY5Y cells and differentiated human neural precursor cells. Several parameters of toxicity were successfully measured including cell-viability in SH-SY5Y cells and estimation of sub-cytotoxic doses which were used to study the effects of signalling inhibitors, measurement of mitochondrial transmembrane potential, reactive oxygen species formation, inhibitory activity towards mitochondrial complex I/II, protein expression after acute and chronic toxin treatment and changes in gene expression. Twenty nine commonly used pesticides were screened for potential PD involvement, using cell viability and Alamar Blue reduction assay in SH-SY5Y cells. Most chemicals showed low toxicity using this system. Chemicals known (MPTP or MPP+) or thought to be involved with PD (e.g. paraquat) showed significant toxicity at the highest chosen dose i.e. 1mM (MPTP/MPP+ caused 20-30% reduction in cell-viability at 1mM whereas paraquat caused 60-70% reduction at 1mM). Significant toxicity was observed at concentrations as low as 0.01mM (60-70% reduction in cell-viability after maneb and mancozeb exposure) and 0.1mM (60%, 50%, 80% and 40% reduction in cell-viability after diquat, epoxiconazole, fluroxypyr-ester and mecoprop-methyl ester treatment respectively). Toxin exposure of human midbrain neurones (hNPCs) derived from embryonic neural stem cells showed that hNPCs were more vulnerable at 0.01mM and 0.1mM than SH-SY5Y cells (except maneb, mancozeb and fluroxypyr ester). Pharmacological inhibition of apoptosis showed a marginal but insignificant reduction in toxicity for most chemicals whereas macroautophagy inhibition had no effect. The absence of any effect of caspase inhibitors, with the exception of diquat, may indicate caspase independent induction of cell death markers like PARP-1 suggesting that toxin treatment seems to cause caspase independent cell death involving RIP. This was shown by using Necrostatin-1, a RIP1 and necroptosis inhibitor, which significantly increased viability (greater than 90% recovery vs. untreated cells) in diquat (0.1mM), mancozeb (0.05mM) and maneb (0.05mM) treated cells. Other results suggested possible involvement of chaperone-mediated autophagy (CMA) with diquat, maneb and mancozeb toxicity which showed increased lysosomal accumulation. Mitochondrial energetics were not affected after acute and chronic toxin exposure which did not affect the mitochondrial complex I or II activities. Coincidentally, cells exposed chronically to diquat appeared to down-regulate expression of autophagic and apoptotic response genes. It can be concluded that these agrochemicals exert their toxicity through distinct mechanisms including indirect energy depletion and direct damage to cell components and show significant toxicity possibly due to ROS generation causing necroptosis and CMA induction.

APA, Harvard, Vancouver, ISO, and other styles

33

Fenlon, Katie Alexandra. "Fate, Behaviour and Bioavailability of Pesticides in Soils." Thesis, Lancaster University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504165.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Buffin, David Gareth. "UK pesticides policy - a policy paradigm in transition?" Thesis, City University London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511776.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

McCracken, Nigel William. "Role of esterases in the detoxification of pesticides." Thesis, University of Newcastle Upon Tyne, 1991. http://hdl.handle.net/10443/550.

Full text

Abstract:

Occupational exposure of pesticides occurs via inhalation through the lungs or by absorption through the skin. The assessment of the possible importance of these extrahepatic tissues in the hydrolysis of pesticides is important. Although the liver has been shown to be the most metabolically active tissue, both the skin and lung have the ability to metabolise pesticides. Therefore, the possibility exists that pesticides which are absorbed through the lung and skin may undergo first pass metabolism in these tissues. In the study, the esterase enzymes responsible for the hydrolysis and subsequent detoxification of a number of pesticide substrates were identified and quantified. Esterases which hydrolysed the pesticides fluazifop-butyl and carbaryl and phenylacetate, a marker substrate for esterase activity, were found to be distributed in the microsomal fraction of the liver and lung and in the blood. In vitro studies in the rat show that lung, skin and plasma have an important role to play in the first pass metabolism of the pesticides fluazifop-butyl and carbaryl. In paraoxon hydrolysis, the plasma plays an important role in first pass metabolism, whereas the lung and skin have little effect. With the use of inhibitors and inducers these esterase enzymes were characterised as `A' or `B' esterases. Fluazifop-butyl and carbaryl were hydrolysed by carboxylesterase, a `B' esterase, whereas paraoxon was hydrolysed by paraoxonase, an `A' esterase. Phenylacetate was found to be hydrolysed by both `A' and `B' esterases. Parallel studies were carried out in human liver and blood to establish whether the rat was an appropriate model for study of the detoxification of pesticides by esterases. Studies have shown that there is considerable similarity in the nature of human and rat esterase enzymes, although there are significant differences in absolute activities.

APA, Harvard, Vancouver, ISO, and other styles

36

Orton, Frances. "Investigation into the effects of pesticides on amphibians." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/2456.

Full text

Abstract:

Amphibian population decline is a recognised phenomenon spanning at least the last 40 years, and it is likely that a number of factors have contributed, including environmental contamination. Amphibians are vulnerable to agrochemical uptake as they must breed in water, and often spend the aquatic phase of their lifecycle in agricultural water bodies, which may contain a complex mixture of biologically active chemicals. Endocrine disrupting compounds may cause reproductive effects in humans and wildlife, although the link between pesticides and endocrine disruption is largely unknown. Therefore, in this study, the role of pesticides in endocrine disruption, in relation to amphibian metamorphosis and reproductive development, was investigated. To achieve this objective, population data were used to select suitable field sites, water from which was tested for endocrine activity using the yeast estrogen/androgen screen, hepatocyte culture (estrogenic response), and a transgenic Xenopus test (thyroid disruption). Toad (Bufo bufo) specimens from a subsample of these sites were used to compare morphology, thyroidal, and gonadal development of caged and wild-caught tadpoles/metamorphs, to their laboratory-raised counterparts. In addition, environmentally relevant pesticides were tested for endocrine effects in vitro, and a short-term in vivo exposure was used to assess the predictive ability of the in vitro screens in Xenopus. Mortality of Bufo bufo was high in both laboratory-reared and caged individuals, which hindered the interpretation of results due to low n values. However, laboratory-reared individuals from different sites had distinct morphology and gonadal differentiation, possibly suggesting maternal transfer, a latent effect of the pond environment, and/or genetic effects. In addition, caged and wild-caught individuals were smaller, metamorphosed later, and had retarded gonadal differentiation or increased incidence of intersex, compared to their laboratory-reared counterparts. Extracts of water samples from these sites were predominantly anti-estrogenic, and/or anti-androgenic in yeast based assays, and this was also the effect observed in response to environmentally relevant pesticides tested in the same assays. Pesticides also affected ovarian steroidogenesis in vitro, and pentachlorophenol had a reprotoxic effect on adult female Xenopus laevis. Data reported in this study suggest there may be endocrine disrupting effects in native amphibians in the agricultural landscape, although further investigation is needed to confirm these findings.

APA, Harvard, Vancouver, ISO, and other styles

37

Cagnini, Andrea. "A disposable biosensor for organophosphorus and carbamic pesticides." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339885.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Özer, Serdar Sofuoğlu Aysun. "Measurement Of Henry's Law Constant Of Organochlorinated Pesticides/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimyamuh/T000344.pdf.

Full text

Abstract:

Thesis (Master)--İzmir Institute of Technology, İzmir, 2005.
Keywords: Organic pollutants, thermodynamic properties, Henry's law constant, Organochlorinated pesticides. Includes bibliographical references (leaves. (leaves. 49-53).

APA, Harvard, Vancouver, ISO, and other styles

39

Lord, Simon. "The interactions of pesticides with free-living protozoa." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760558.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Wong, Hie Ling. "Assessment of non-dietary, human exposure to pesticides." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/21539/.

Full text

Abstract:

Assessment of non-dietary, human exposure to pesticides is an integral part of pesticide authorisation at the EU level. In this thesis, models were used to predict exposure of vulnerable human sub-populations to pesticides and thus to assess risks to health. Two high-quality pesticide usage datasets previously collected by Fera Science Ltd. and for EFSA were analysed. Trends in pesticide usage and major drivers of exposure and thus risk were identified, including any implications for regulatory procedures over the period investigated. Residential exposure of pregnant women living at 100 and 1000 m downwind of treated orchards indicated improving fate (vapour pressure) and hazard profiles (reproductive/developmental toxicities) of pesticides applied in England and Wales over a 25-year period (1987, 1996, 2004 and 2012). Overall, results reflected the influence of changing policies during the 1990s and the ongoing review programme at national level. Assessment of 50 agricultural professional operators across five cropping systems in Greece, Lithuania and the UK indicated a range of applications with potential for risk. Estimated exposure was significantly influenced by variations in agricultural practices and working behaviours involving the use of personal protective measures, including the extensive use of wettable powder formulations in Greece and large areas of land treated per day in Lithuania and the UK. The 50 selected professional operators handled a range of active substances and/or co-formulants with known/possible endocrine disrupting activity during single spray days. At maximum, one operator handled five such active substances and ten such co-formulants in a single day. Thus, higher risk is expected in mixture than that predicted for single active substances. Although the use of models in risk assessment has inherent uncertainties, these results add to the existing body of knowledge and allow a holistic assessment of the pesticide regulatory procedures over the period investigated.

APA, Harvard, Vancouver, ISO, and other styles

41

Blackwell, Alison. "The behavioural effects of formamidine pesticides in Lepidoptera." Thesis, University of Bristol, 1987. http://hdl.handle.net/1983/d31fbc39-5dd8-4285-abd5-75dd8f2e99b2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Falconer, Katherine. "Environmental policy and the use of agricultural pesticides." Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/271974.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Vian, Laurence. "Etude de l'exposition aux pesticides dans les serres." Montpellier 1, 1985. http://www.theses.fr/1985MON13510.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Burdge, Ryan Brennan. "Songbirds, Pesticides, and Golf Courses: Exposure and Effects." W&M ScholarWorks, 2009. https://scholarworks.wm.edu/etd/1539626888.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Zheng, Guanyu. "Bioremediation of organochlorine pesticides contaminated soil with microemulsions." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1245.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Suddaby, Laura. "Investigation into irreversible sorption of pesticides to soil." Thesis, University of York, 2012. http://etheses.whiterose.ac.uk/2725/.

Full text

Abstract:

The importance of extremely slow retention and release has superseded the notion that sorption of pesticides to soil is an instantaneous and reversible process. A fraction of sorbed pesticide is also often reported to bind irreversibly to the soil matrix. This has important implications for pesticide mobility and bioavailability. It is essential to understand sorption phenomena to allow accurate prediction of pesticide fate within the soil environment. This thesis describes the result of applying a sequential extraction procedure, based on the principles of isotope or “self-exchange”, to nine pesticide/soil systems. The significance of irreversible sorption in controlling pesticide mobility was assessed using isotope exchange (12C and 14C) to characterise pesticide exchange kinetics in-situ over protracted time-scales. Sequential extraction increased in harshness in the order: isotope exchange < forced isotope exchange < solvent extraction. Three pesticides (one neutral, one basic, one acidic) and three temperate, arable soils (ranging in texture and pH) were studied. A three-site sorption model was developed to further interpret the data obtained. Although results showed the experimental design of the isotope exchange technique was not powerful enough to identify whether remaining sorbed pesticide was participating in slowly reversible or irreversible sorption, the forced isotope exchange procedure was able to provide an indication of amounts of pesticide not participating in exchange between the soil and solution. Under abiotic conditions, only minimal amounts of initial-applied pesticide were found to take part in irreversible binding. Soil combustion quantified irreversible sorption in the order: chlorotoluron (≤ 2.27 ± 0.36%) > prometryn (≤ 1.35 ± 0.60%) > hexaconazole (≤ 0.50 ± 0.06%). Varying the soil composition had little effect on amounts of irreversibly sorbed pesticide, probably due to the small amounts of irreversible sorption observed overall. These results suggest that the vast majority of sorbed chlorotoluron, prometryn and hexaconazole (in the parent form) participated in very slow but reversible binding, a result also confirmed by the three-site sorption model. Pesticide sorption behaviour is a complex process. Although sorption phenomena are still not fully understood, these results provide a greater insight into the significance of irreversible binding for predicting pesticide fate.

APA, Harvard, Vancouver, ISO, and other styles

47

Khoury, Randa. "Comportement de deux produits phytosanitaires dans deux sols typiques libanais." Perpignan, 1999. http://www.theses.fr/1999PERP0346.

Full text

Abstract:

Nous avons, au cours de ce travail, etudie le devenir d'un fongicide le triadimefon, et d'un herbicide la metribuzine dans deux sols typiques libanais : l'un argileux et l'autre de type loam sableux. Les differents parametres influant la degradation de ces deux molecules ont ete egalement evalues. Apres la mise au point d'une methode analytique d'extraction et de dosage faisant appel a la cpg et plus particulierement a la clhp sous forme de paire d'ions, nous avons determine les differents processus de degradation abiotique et biotique des deux molecules : photolyse sous uv directe, en milieu aqueux et apres adsorption sur les deux sols, effets de la temperature et de l'humidite ainsi que l'influence de la teneur en matieres organiques. L'etude de la biodegradation a ete egalement conduite avant et apres sterilisation des sols, afin de mettre en evidence le role joue par la flore microbienne. En une deuxieme etape, nous avons determine les isothermes d'adsorption et de desorption de ces molecules sur deux types de sol : un loam sableux et un argileux a deux horizons differant en la teneur en matiere organique. L'etude a ete completee par le suivi de la mobilite, de la persistance et de la degradation de ces deux molecules sur colonnes de sol reconstitue, et par une etude en plein champ de leur comportement.

APA, Harvard, Vancouver, ISO, and other styles

48

Isherwood, Karen Elizabeth. "Quorum sensing in Yersinia pestis." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364667.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Blackman, Lois. "Strain differentiation of Yersinia pestis." Thesis, University of Leicester, 2001. http://hdl.handle.net/2381/29822.

Full text

Abstract:

Verification procedures are required to ensure compliance with the Biological and Toxins Weapons Convention (BTWC). Strain differentiation analysis may need to be performed on samples that do not harbour live bacteria and may contain other microorganisms. Thus the method employed must be non-culture based and specific to the bacterial species. Three Polymerase Chain Reaction (PCR) based assays were evaluated for their potential to specifically differentiate strains of Yersinia pestis. Two of the techniques, Insertion Sequence - Flanking Region Amplification PCR (IS-FRAP) and Variable Number of Tandem Repeats - PCR (VNTR-PCR), demonstrated specific and reproducible differentiation of a test panel of 84 Y. pestis isolates. These isolates included biotyped and/or ribotyped strains, previously untyped isolates and repetitive subcultures of Y. pestis CO92. Sites of chromosomal and plasmid insertion of the IS100 element were analysed by IS-FRAP. The amplification profiles divided the test panel isolates into 16 types. Two octonucleotide VNTR sequences were identified in the proximity of the same IS100 element. The observation of 11 alleles of VNTR-8A upstream of 4 alleles of VNTR-8B enabled the differentiation of the test panel isolates into 19 VNTR-PCR types. Strains isolated from similar geographical locations often displayed the same VNTR-PCR type. These PCR techniques were developed into prototype assays that may be suitable for the analysis of BTWC samples. Homologous sequences to the Y. pestis VNTR regions were analysed in Y. pseudotuberculosis strains. The octonucleotide sequence of VNTR-8A was not repeated in Y. pseudotuberculosis and was flanked by 361bp of DNA not identified in Y. pestis strains. Recombination events leading to the formation of the VNTR are hypothesised.

APA, Harvard, Vancouver, ISO, and other styles

50

Gadbury, Calvin J. "Measure the efficacy of Indiana's private pesticide applicator certification program on private pesticide applicator's attitudes toward methods of limiting pesticide exposures." Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1221288.

Full text

Abstract:

The purpose of this study was to assess whether Indiana's private applicator training program affects private pesticide applicators' attitudes toward personal safety. The theoretical framework for this study was Ajzen and Fishbein's Theory of Reasoned Action. The sample was created by recruiting the enrollees participating in four private applicator training sessions selected at random. Sixty private pesticide applicators participated in a year long longitudinal study. Results revealed no significant improvement in positive attitudes toward pesticide safety was noted as a result of training. However, differences in attitudes toward pesticide safety were observed among selected demographic groups. Attitudes were most positive ten months after training indicating factors other than training were affective in developing positive attitudes toward pesticide safety. Selected factors other than training are discussed in relationship to attitude development.
Department of Natural Resources and Environmental Management

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Pestides'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles