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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.
1

Using a biotrickling filter for degradation of cypermethrin, an insecticide frequently used in Tahuapalca, Bolivia

Enstedt, Henric January 2013 (has links)
The feasibility of using bench-scale biotrickling filter reactors inoculated with the fungus UBAF004, isolated from soil in Tahuapalca, for treatment of water contaminated with cypermethrin was investigated. Wood chips, gravel and ceramics were tested as packing materials for the reactors in batch experiments in small glass flasks. Wood proved to be the material on which the fungus grew best and was thus chosen as the packing material for the reactors. It was determined that UBAF004 had quite low competitive strength compared to other microorganisms when growing on wood and gravel but not necessarily on ceramics. UBAF004 grew slowly in the reactors leading to poor degradation performance. The results obtained indicate that it will be challenging to use UBAF004 for treatment of water contaminated with cypermethrin in Tahuapalca. The single largest issue is to find a way to establish a stable population of the fungus in the reactor and to protect it from being out competed by other microorganisms. / <p>Opponent: Veronika Granat</p>
2

Gel-based solid dosage form for pesticide delivery

Massinga, Pedro Horacio 26 March 2008 (has links)
The aim of this research was to develop a solid dosage form containing 1.5 g of the pesticide cypermethrin. The dosage should be stable in a tropical climate. In addition, it is to disintegrate and disperse in 10 L of tap water within 3 minutes. Such dissolution should yield a 150 ppm dispersion of cypermethrin, stable for at least one week. This provides for a dip dispersion to treat ticks and fly infestation on livestock. A new solid dosage was formulated as the scope of this research. It is a gel-based solid dosage form. Polymer electrolyte ASP4 - a copolymer of methacrylic acid, ethyl acrylate and diethyl maleate, was used to produce the gel. Preliminary tests revealed that ASP4- based gel, on its own, failed to meet the required dissolution time of 3 minutes. Strong entanglements of ASP4 chains impeded rapid dissolution. These strong entanglements occurred owing to the use of a high concentration of ASP4. Reducing the concentration of ASP4 yielded a solution of high viscosity instead of a gel. It was therefore decided to Gel-based solid dosage form for pesticide delivery use a superabsorbent (Product Z1069) in conjunction with ASP4 to produce the gel. Product Z1069 is a cross-linked sodium polyacrylate. Before producing the gel, a 1:1.5 by mass oil/water (O/W) emulsion was prepared using the phase-inversion route. The water (W) phase comprised 85.9% distilled water, 3.9% ASP4 at 20% dispersion, 8.6% sodium carbonate (0.5 M) and 1.6% Emulsogen EL. All concentrations are indicated in mass %. The oil (O) phase consisted of 76.9% cypermethrin, 19.3% Solvesso S200 and 3.8% Phenyl Sulphonate CA, also by mass. This emulsion was gelled by adding the superabsorbent Product Z1069 (ca. 37.5% by mass relative to the W phase of the emulsion). The superabsorbent strongly absorbed water, depleting it from the emulsion. This resulted in an increase of the effective concentration of ASP4 in the water phase of the emulsion. This increase of the polymer electrolyte concentration brought about a gel-like state corresponding to the desired solid dosage form. Rheometry confirmed that the dosage form maintained a solid gel-like consistency at 50°C. The dosage contained 24.6% m/m cypermethrin. Thus, the required dosage of 1.5 g was achieved in pellets weighing ca. 6.1 g. Such pellets rapidly disintegrated with mild stirring in 10 L of tap water. Complete pellet disintegration and active dispersion occurred within 2.5 minutes at ambient temperature (25 ± 2°C). / Dissertation (MSc)--University of Pretoria, 2008. / Chemistry / unrestricted
3

Die ökotoxikologische Bewertung multipler Pestizideinträge in aquatische Ökosysteme der Vergleich einer einmaligen mit einer mehrmaligen Pyrethroidbelastung /

Dawo, Ursula. Unknown Date (has links)
Techn. Universiẗat, Diss., 2005--München.
4

Degradation of Cypermethrin by indigenous bacteria in local industrial, beech- and spruce-forest soil

Engblom, Joakim January 2007 (has links)
<p>Soil from local beech-forest, spruce-forest and an industrial area was taken. Control- and test-microcosms containing 150 ml soil were spiked with cypermethrin 0,4 mg/ml soil. Cypermethrin residues were extracted on day seven and 14.</p><p>Cyclohexane and deionized water was utilized in multiple step extraction processes. Samples were analyzed in a Gas Chromatograph (GC) with electron capture detector (ECD). </p><p>Concentration values for the samples were highest for beech-forest soil and lower for the other two soil-types. Statistical differences in concentrations between control- and test-microcosms for each soil-type on day seven and day 14 were evaluated with Mann Whitney U tests. Significant result was only found in the industrial 14-day group. The small amounts of cypermethrin in the extracts could not only be ascribed to a bacterial degradation process. Used insecticide has a high bonding affinity for particles and is sequestered in soil.</p>
5

Degradation of Cypermethrin by indigenous bacteria in local industrial, beech- and spruce-forest soil

Engblom, Joakim January 2007 (has links)
Soil from local beech-forest, spruce-forest and an industrial area was taken. Control- and test-microcosms containing 150 ml soil were spiked with cypermethrin 0,4 mg/ml soil. Cypermethrin residues were extracted on day seven and 14. Cyclohexane and deionized water was utilized in multiple step extraction processes. Samples were analyzed in a Gas Chromatograph (GC) with electron capture detector (ECD). Concentration values for the samples were highest for beech-forest soil and lower for the other two soil-types. Statistical differences in concentrations between control- and test-microcosms for each soil-type on day seven and day 14 were evaluated with Mann Whitney U tests. Significant result was only found in the industrial 14-day group. The small amounts of cypermethrin in the extracts could not only be ascribed to a bacterial degradation process. Used insecticide has a high bonding affinity for particles and is sequestered in soil.
6

The Effect Of Ecotoxicants On The Aquatic Food Web And Prey-predator Relationships

Akkas, Sara Banu 01 July 2009 (has links) (PDF)
There is considerable need for higher-tier aquatic risk assessment and information on toxicant-induced molecular alterations in lower aquatic invertebrates. Thus the current study&rsquo / s priorities were two-fold: a novel approach utilizing higher-tier ecotoxicity bioassay-guided ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared) spectroscopy to better understand the impact of the presence of fish predation pressure &ndash / mimicked by predator-exuded info-chemicals &ndash / on cypermethrin or salinity toxicity to Daphnia pulex &ndash / key-stone species in lake ecosystems &ndash / and ultimately better assess toxicant-induced alterations at both organismal and molecular levels. This approach indicates that even low concentrations of cypermethrin/salinity had significant molecular and organismal effects on daphnids. Fish kairomone acted as a major factor affecting toxicant severity, interacting antagonistically below a threshold and synergistically above. Moreover, molecular ATR-FTIR spectroscopic results, clearly consistent with organismal responses, showed that both cypermethrin and salinity lead to decreased contributions of lipid and proteins to the investigated daphnid systems. It is further suggested that the action mechanism of the fish-exuded kairomone occurs via the lipid metabolism of Daphnia. Hence, infrared spectroscopic results enabled detection of early molecular alterations, whose effects might not always be observable at the organismal level. The results of this study clearly indicate that the simplistic nature of standard ecotoxicology tests hinders a precise judgment of threats imposed by chemicals of interest. Furthermore, it has been shown that ATR-FTIR spectroscopy has considerable potential for studies on daphnid responses to varying environmental conditions. Thus, this study presents a starting point for increasing the environmental realism of aquatic risk assessment.
7

Rezistence blýskáčka řepkového (Meligethes aeneus, Fabr. 1775) k pesticidům na vybraných lokalitách jižní Moravy

Kubátová, Kateřina January 2014 (has links)
My thesis is devoted to the resistance of pollen beetle (Meligethes aeneus, son. Brassicogethes aeneus Fabricius, 1775) to pesticides in selected localities in southern Moravia. Collecting adults was performed in the spring of 2013 by tapped into polyethylene bags. Adults are collected from the stands of oilseed rape, mustard and poppy. Tests were performed on the basis of the methodology of Insecticide Resistance Action Committee number 011, 021, 025. In total, we tested the pollen population from 18 locations. For testing, we used the following chemical substances: Biscaya 240 OD, cypermethrin, lambda-cyhalothrin, tau-fluvalinate, etofenprox, chlorpyrifos(ethyl). We evaluated 100% of the registered dose of pesticides after 24 hours. From the results of the individual populations, we found large differences in resistance to chemicals.
8

Rezistence škůdců řepky k vybraným účinným látkám insekticidů

Hajda, Tomáš January 2018 (has links)
Resistence population of pollen beattle on selected locations of Moravia and Silesia were observed during the 2017. Beattles were taked off in the field during spring and their sensitivity to insecticides active substances indoxacarb, chlorpyrifos, thiacloprid, tau-fluvalinate, cypermethrin and lambda-cyhalothrin were tested in laboratory. Tested using methods of IRAC – 11, 21, 25 and 27. Mortality of beattles at various concentrations of active substances was evaluated after 24 hours. Levels of resistance were changed for individual location.
9

Developmental neurotoxicity of persistent and non-persistent pollutants : Behavioral and neurochemical assessments of a perfluorinated compound, pesticides and interaction effects

Lee, Iwa January 2015 (has links)
The focus of this thesis was to investigate developmental neurotoxic effects of different persistent and non-persistent environmental pollutants, alone or in binary mixtures, when exposure occurs during a critical period of brain development, in mice. The compounds investigated included a perfluorinated compound, perfluorohexane sulphonate (PFHxS), and four different pesticides, endosulfan, cypermethrin, chlorpyrifos and carbaryl. Both persistent and non-persistent pollutants are detected in the environment and in humans, which shows that exposure to these compounds is occurring in real life. Humans can therefore be exposed to various pollutants during their whole lifetime, starting from the gestational period to adulthood. Furthermore, exposure to environmental pollutants is rarely exclusive to a single compound, but rather occurs through combinations of various pollutants present in the environment. Exposure to environmental pollutants during human brain development have been suggested to be a possible cause for neuropsychiatric disorders, such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Previous studies have shown that chemicals can induce irreversible disorders in brain function when exposure to these chemicals occurs during a critical defined period of the brain development known as the brain growth spurt (BGS). The BGS is characterized by a rapid growth and development of the immature brain. In humans, and mice, this period also overlaps the lactation period indicating that newborns and toddlers can be exposed via mothers’ milk as well. This thesis has shown that a single oral exposure to PFHxS, endosulfan, cypermethrin, chlorpyrifos or carbaryl can induce developmental neurotoxic effects in mice, when exposure occurs during a critical period of brain development. These effects are manifested as persistent altered adult spontaneous behavior in a novel home environment, modified habituation, altered susceptibility of the cholinergic system and changed levels of neuroproteins in the mouse brain. Furthermore, a single neonatal co-exposure to a binary mixture of carbaryl/chlorpyrifos or PFHxS/endosulfan can interact and exacerbate the adult behavioral effects. These effects were seen at dosages were the single compound did not elicit a response or induced a much weaker behavioral effect. This indicates that risk assessments conducted on single compounds might underestimate interaction effects of mixtures when co-exposed.
10

Situação da resistência do rhipicephalus (boophilus)Microplus à cipermetrina e amitraz no planalto Catarinense e proposta de um teste de imersão deLarvas para avaliação de carrapaticidas / Resistance level of Rhipicephalus (boophilus) microplus to cypermthrin and amitraz in the Santa catarina Plateau and development of a larvae immersion test to tick acaricides

Veiga, Luana Paula Haubold Neis 21 August 2007 (has links)
Made available in DSpace on 2016-12-08T16:24:03Z (GMT). No. of bitstreams: 1 PGCV07MA022.pdf: 204417 bytes, checksum: 03ef70e1c1888475b7a6459fa03a0b63 (MD5) Previous issue date: 2007-08-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aims of this study were to evaluate the degree of resistance of Rhipicephalus (Boophilus) microplus to cypermethrin and amitraz in the Santa Catarina Plateau, and to develop a technique for the evaluation of acaricides by larvae immersion. Engorged female ticks, collected between January 2004 and May 2006, were sampled from 20 ranches in the Santa Catarina Plateau (samples by convenience) and also received directly from ranchers (20 samples). Engorged females were submitted to in vitro immersion tests in cypermethrin (0.015%) and amitraz (0.025%) acaricides. The results indicated resistance of R. (B.) microplus to cypermethrin and amitraz to be rising in bovine herds in the Santa Catarina Plateau. To carry out the larvae immersion test, 30 engorged females were collected in a ranch in Lages. Larvae used in the immersion test were obtained from 10mg of eggs placed into 5ml disposable syringes, previously prepared and kept in controlled conditions of laboratory (27 + 1 0C and 80 + 10% UR), and collected between the third and the twelfth day of oviposition. Seven to ten days old larvae were submitted to the acaricide laboratory test, in ten replications, by their immersion in eight dilutions of commercial acaricides (amitraz or cypermethrin), for 30 seconds; for each replication and commercial product, a control group was immersed in distilled water. Results were evaluated 24 hours after each treatment by counting the number of live and dead larvae. The lethal dose (LD50) was obtained from a regression curve by the Sigma Plot program. The proposed acaricide laboratory test procedures by larvae immersion offered promising results for the evaluation of acaricides, proving useful for the calculation of the mean LD50 for cypermethrin and amitraz / A realização deste trabalho teve como objetivos avaliar a situação da resistência doRhipicephalus (Boophilus) microplus à cipermetrina e ao amitraz no Planalto Catarinense e desenvolver uma técnica de avaliação de carrapaticidas por imersão de larvas. No período de janeiro de 2004 a maio de 2006, foram coletadas amostras de teleóginas em bovinos de 20 propriedades, no Planalto Catarinense (amostras por conveniência) e recebidas 20 amostras de teleóginas enviadas por produtores rurais. Foram realizados testes in vitro de imersão de teleóginas em acaricida à base de cipermetrina (0,015%) e amitraz (0,025%). Constatou-se que a resistência do carrapato R. (Boophilus) microplus aos carrapaticidas cipermetrina e amitraz é crescente no rebanho bovino do Planalto Catarinense. Para a realização do teste de imersão de larvas foram coletadas 30 teleóginas de bovinos de uma propriedade rural do município de Lages. As larvas utilizadas no teste de imersão foram obtidas de ovos da postura do terceiro ao décimo segundo dia, que foram acondicionados 10mg por seringa, descartável de 5ml, previamente preparadas e mantidas em câmara climatizada até a eclosão das larvas. Para o teste carrapaticida foram utilizadas larvas de sete a dez dias submetidas à imersão, por 30 segundos, em oito diluições de produtos carrapaticidas comerciais à base de amitraz e de cipermetrina, cada uma com dez repetições. O grupo controle para cada repetição e produto, foi imerso em água destilada. A leitura foi realizada 24 horas após o tratamento com a contagem de larvas vivas e mortas. O cálculo da dose letal 50 foi realizado a partir da linha de regressão, utilizando o programa Sigma plot . A metodologia proposta para o teste carrapaticida por imersão com larvas apresentou resultados promissores para avaliação de carrapaticidas e pode ser utilizada para calcular a média da dose letal50 para os acaricidas à base de cipermetrina e amitraz

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