Thesis (Ph.D.)--Tennessee Technological University, 2007. / Includes bibliographical references.

Th. doct.--Géochim.--Orléans, 1997. / Bibliogr. p. 169-173. Résumé en français et en anglais.

Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on Feb. 8, 2007). Thesis advisor: Mark Radosevich. Vita. Includes bibliographical references.

This report describes the results of investigations carried out with the view to find an alternative for MIBK as solvent for the production of atrazine as currently practised by Dow AgroSciences in South Africa. The main motivating factors for the said investigation was: · to increase the yield of atrazine produced, · to reduce the amount of organics, consisting essentially of reaction solvent containing dissolved product, in the aqueous process effluent, and · to improve the properties of the solid (crystalline) product to enable easier product formulation. Synthetic reactions carried out in the absence of organic solvent, i.e. in essentially a 10% NaCl solution containing a surfactant, proved rather disappointing. Low yields of atrazine were obtained together with relatively large amounts of by-products such as propazine and simazine, irrespective of the nature of the surfactant. The reason for the low yield of atrazine and high yields of by-products were established in competing substitution reactions. In these reactions, IPA was reacted with an equimolar mixture of cyanuric chloride and mono-i (first reaction intermediate) in both aqueous medium and in toluene as reaction solvent. The results of these experiments indicated that in aqueous medium IPA reacts faster with mono-i than cyanuric chloride to give propazine as by-product. In toluene, however, the preferred reaction is with cyanuric chloride to give more mono-i as product. Toluene was investigated as an alternative organic solvent to MIBK in view of its desirable properties such as low solubility in water and ease of recovery and recycling. The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (HCl acceptor), both by means of benchscale reactions and reaction calorimetry. Reaction energy profiles indicated that both the reaction of secondary amine/NaOH and primary amine/NaOH were virtually instantaneous. This implies that the reaction can be performed under feed control conditions. Of particular importance in ensuring high yields of high purity product was accurate temperature control (since both reaction steps are highly exothermic) and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the first reaction intermediate, with IPA in cases of local excesses of reagent. Under optimum conditions, a yield of atrazine > 97% could be achieved where the resultant product was well within stipulated product specifications. In view of the results obtained, the following recommendations regarding the synthesis of atrazine in toluene as reaction solvent can be made: · Use a reagent addition sequence that staggers the addition of amine and NaOH in such a manner that amine is added first for a short while, followed by the simultaneous addition of amine and NaOH, and ending with NaOH. Use two reaction vessels in series, one for the IPA addition reaction and one for the MEA addition reaction. In this manner the reaction can be run on a continuous basis since no lag time between amine additions is required. Also, smaller reactors may be used whilst maintaining high production rates. Smaller reactors will improve both temperature control and mixing of reagents.

The impact of different atrazine concentration on a chitinolytic actinomycete and the biodegradation of atrazine by this microbe was examined.Isolates were grown in pure culture in Chitin Mineral Salts Broth with and without addition of atrazine for a two month incubation at room temperature on a rotary shaker. Visual observations, analysis by High Performance Liquid Chromatography (HPLC) and radioisotope methodology were used to determine this impact on chitinolytic activity. Analysis by HPLC and Gas Chromatography with Electron Capture Detector (GC with ECD) were used to determine the breakdown of atrazine.No atrazine derivatives were determined by HPLC and GC analysis. Only the 0.1 ppm atrazine concentration with the actinomycete culture demonstrated tolerance to the atrazine and showed chitinolytic activity in the radioactive assay and chitin derivatives by HPLC. SEM and TEM work determined that the actinomycete was actually a Streptomyces sp. / Department of Biology

A Dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Medicine University of the Witwatersrand Parktown, Johannesburg, South Africa June 2017 / Atrazine, an extensively used herbicide is amongst the commonly detected herbicides in groundwater. Atrazine concentrations as low as 0.01μg/l have been implicated to affect frog populations, thus much attention has been placed on its use and safety. Several studies have examined atrazine effects on reproductive organs, immune systems and population fitness of adult Xenopus laevis species and we found no studies on the effects of atrazine on the liver and kidney. This study investigated biochemical and histopathological effects of chronic exposure to atrazine on livers and kidneys of adult Xenopus laevis frogs, post metamorphosis. Forty male frogs were randomly divided into four groups (A -D) of 10 frogs each, housed in stainless silver tanks with 60L of water and atrazine concentration of 0μg/l A: control, B: 0.01μg/l, C: 200μg/l and D: 500μg/l respectively, for 90 days. Liver (ALT, ALKp and AST) and kidney (urea, creatinine) biomarkers, malondialdehyde, an indicator of lipid peroxidation, histopathology, melanomacrophage percentage area and fibrosis were examined. Significant increases of ALT and creatinine were observed at 200 and 500μg/l (P<0.05). Malondialdehyde was significantly increased at 500μg/l (P<0.05). Histopathologically, the liver showed disorganization in the arrangement of hepatic cords, hypertrophied hepatocytes, hepatocyte vacuolization, vascular congestion and dilation, infiltration of inflammatory cells and apoptosis and/or necrosis, with the highest atrazine concentration causing the most adverse effects. The kidney showed glomerular atrophy and degeneration, tubular lumen dilation, vacuolization and degeneration of thick loop of Henle tubule epithelial cells. Melanomacrophage percentage areas were significantly decreased at 0.01μg/l and 500μg/l and significantly increased at 200μg/l (P<0.05). No significant fibrosis was observed in all treated groups. The results suggest that very low and high environmentally relevant doses of atrazine have the ability to adversely affect organs of amphibian species and potentially related aquatic organisms. / MT2017

by Chan Cho-Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 161-173). / Text in English; abstracts in English and Chinese. / by Chan Cho-Yin. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.vi / List of Figures --- p.xii / List of Plates --- p.xv / List of Tables --- p.xvi / Abbreviations --- p.xix / Equations --- p.1 / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Atrazine --- p.1 / Chapter 1.1.1 --- Characteristics of atrazine --- p.1 / Chapter 1.1.2 --- Use of atrazine --- p.7 / Chapter 1.1.3 --- Inhibitory mechanisms --- p.7 / Chapter 1.1.4 --- Global annual consumption --- p.7 / Chapter 1.1.5 --- Environmental fate --- p.8 / Chapter 1.1.5.1 --- Major intermediates --- p.10 / Chapter 1.1.6 --- Ecotoxicity --- p.10 / Chapter 1.1.6.1 --- Toxicity towards microorganisms --- p.10 / Chapter 1.1.6.2 --- Toxicity towards invertebrates --- p.12 / Chapter 1.1.6.3 --- Toxicity towards vertebrates --- p.15 / Chapter 1.1.7 --- Environmental regulations --- p.16 / Chapter 1.2 --- Treatments of atrazine --- p.16 / Chapter 1.2.1 --- Physical treatments --- p.16 / Chapter 1.2.2 --- Chemical treatments --- p.18 / Chapter 1.2.3 --- Advanced Oxidation Processes (AOPs) --- p.19 / Chapter 1.2.4 --- Photocatalytic Oxidation (PCO) --- p.21 / Chapter 1.2.4.1 --- Cyanuric acid --- p.26 / Chapter 1.2.5 --- Biological treatments --- p.33 / Chapter 1.2.6 --- Integration of treatment methods --- p.36 / Chapter 2 --- Objectives --- p.38 / Chapter 3 --- Materials and methods --- p.39 / Chapter 3.1 --- Photocatalytic oxidation (PCO) reaction --- p.39 / Chapter 3.1.1 --- Chemical reagents --- p.39 / Chapter 3.1.2 --- Photocatalytic reactor --- p.39 / Chapter 3.1.3 --- Determination of atrazine --- p.43 / Chapter 3.1.4 --- Optimization of PCO reactions --- p.43 / Chapter 3.1.4.1 --- Effect of initial hydrogen peroxide concentration --- p.49 / Chapter 3.1.4.2 --- Effect of titanium dioxide concentration --- p.49 / Chapter 3.1.4.3 --- Effect of initial pH --- p.50 / Chapter 3.1.4.4 --- Effect of UV intensities --- p.50 / Chapter 3.1.4.5 --- Internal control of parameters --- p.50 / Chapter 3.1.4.6 --- Combination study of parameters: part one --- p.50 / Chapter 3.1.4.7 --- Combination study of parameters: part two --- p.50 / Chapter 3.1.5 --- Detection methods of atrazine degradation intermediates/products --- p.51 / Chapter 3.1.5.1 --- Gas chromatography-mass spectrometry --- p.51 / Chapter 3.1.5.2 --- High performance liquid chromatography --- p.51 / Chapter 3.1.6 --- Investigation of PCO treated solution --- p.54 / Chapter 3.1.6.1 --- Total organic carbon content --- p.54 / Chapter 3.1.6.2 --- Anions content --- p.54 / Chapter 3.1.6.3 --- pH --- p.56 / Chapter 3.1.6.4 --- Hydrogen peroxide content --- p.56 / Chapter 3.1.6.5 --- Toxicity --- p.56 / Chapter 3.1.6.5.1 --- Microtox® test --- p.56 / Chapter 3.1.6.5.2 --- Amphipod survival test --- p.57 / Chapter 3.2 --- Biodegradation reaction --- p.61 / Chapter 3.2.1 --- Chemical reagents --- p.61 / Chapter 3.2.2 --- Sampling --- p.62 / Chapter 3.2.3 --- Enrichment --- p.62 / Chapter 3.2.4 --- Isolation --- p.65 / Chapter 3.2.5 --- Purification --- p.65 / Chapter 3.2.6 --- Identification of bacterial strain --- p.65 / Chapter 3.2.6.1 --- Gram staining --- p.66 / Chapter 3.2.6.2 --- Catalase and oxidase tests --- p.66 / Chapter 3.2.6.3 --- Sherlock Microbial Identification System (MIDI) --- p.66 / Chapter 3.2.6.4 --- Biolog MicroLog´ёØ system (Biolog) --- p.67 / Chapter 3.2.7 --- Determination of cyanuric acid --- p.67 / Chapter 3.2.8 --- Selection of cyanuric acid degrading bacteria --- p.67 / Chapter 3.2.9 --- Optimization of reaction conditions --- p.67 / Chapter 3.2.9.1 --- Starting medium --- p.68 / Chapter 3.2.9.2 --- Effect of temperatures --- p.68 / Chapter 3.2.9.3 --- Effect of initial pH --- p.69 / Chapter 3.2.9.4 --- Effect of agitation rates --- p.69 / Chapter 3.2.9.5 --- Effect of initial cyanuric acid and glucose concentrations --- p.70 / Chapter 3.2.9.6 --- Investigation of biodegraded solution --- p.70 / Chapter 3.2.9.6.1 --- Glucose content --- p.70 / Chapter 3.2.9.6.2 --- Biodegradation metabolite(s) of cyanuric acid --- p.70 / Chapter 3.3 --- Integration of photocatalytic oxidation and biodegradation --- p.71 / Chapter 4 --- Results --- p.72 / Chapter 4.1 --- Photocatalytic oxidation (PCO) reaction --- p.72 / Chapter 4.1.1 --- Determination of atrazine --- p.72 / Chapter 4.1.2 --- Effect of aeration and mixing --- p.72 / Chapter 4.1.3 --- Effect of initial hydrogen peroxide concentrations --- p.72 / Chapter 4.1.4 --- Effect of titanium dioxide concentrations --- p.78 / Chapter 4.1.5 --- Effect of initial pH --- p.78 / Chapter 4.1.6 --- Effect of UV intensities --- p.78 / Chapter 4.1.7 --- Effect of different internal controls --- p.85 / Chapter 4.1.8 --- "Combination of UV intensities, initial hydrogen peroxide and titanium dioxide concentrations" --- p.85 / Chapter 4.1.9 --- "Combination of initial pH, atrazine concentrations and UV intensities" --- p.94 / Chapter 4.1.10 --- Degradation products detected by GC/MS --- p.94 / Chapter 4.1.11 --- Degradation products detected by HPLC --- p.94 / Chapter 4.1.12 --- Total organic carbon removal --- p.104 / Chapter 4.1.13 --- Anions content --- p.104 / Chapter 4.1.14 --- Solution pH --- p.104 / Chapter 4.1.15 --- Hydrogen peroxide content --- p.108 / Chapter 4.1.16 --- Microtox® test --- p.108 / Chapter 4.1.17 --- Amphipod survival test --- p.114 / Chapter 4.2 --- Biodegradation reaction --- p.118 / Chapter 4.2.1 --- Isolation of bacterial colonies --- p.118 / Chapter 4.2.2 --- Identification and characterization of the isolated bacteria --- p.118 / Chapter 4.2.3 --- Selection of cyanuric acid degrading species --- p.118 / Chapter 4.2.4 --- Effect of temperatures --- p.128 / Chapter 4.2.5 --- Effect of initial pH --- p.128 / Chapter 4.2.6 --- Effect of agitation rates --- p.128 / Chapter 4.2.7 --- Effect of cyanuric acid and glucose concentrations --- p.132 / Chapter 4.2.8 --- Glucose content --- p.132 / Chapter 4.2.9 --- Biodegradation metabolites of cyanuric acid --- p.132 / Chapter 4.2.10 --- Proposed pathway of atrazine degradation by biodegradation enhanced by PCO --- p.138 / Chapter 4.3 --- Integration of photocatalytic oxidation and biodegradation --- p.138 / Chapter 5 --- Discussion --- p.141 / Chapter 5.1 --- Photocatalytic oxidation (PCO) reaction --- p.141 / Chapter 5.1.1 --- Determination of atrazine --- p.141 / Chapter 5.1.2 --- Effect of aeration and mixing --- p.141 / Chapter 5.1.3 --- Effect of initial hydrogen peroxide concentrations --- p.141 / Chapter 5.1.4 --- Effect of titanium dioxide concentrations --- p.143 / Chapter 5.1.5 --- Effect of initial pH --- p.143 / Chapter 5.1.6 --- Effect of UV intensities --- p.144 / Chapter 5.1.7 --- Effect of different internal controls --- p.145 / Chapter 5.1.8 --- "Combination of UV intensities, initial hydrogen peroxide and titanium dioxide concentrations" --- p.145 / Chapter 5.1.9 --- "Combination of initial pH, atrazine concentrations and UV intensities" --- p.146 / Chapter 5.1.10 --- Degradation products detected by GC/MS --- p.146 / Chapter 5.1.11 --- Degradation products detected by HPLC --- p.147 / Chapter 5.1.12 --- Total organic carbon removal --- p.147 / Chapter 5.1.13 --- Anions content --- p.148 / Chapter 5.1.14 --- Solution pH --- p.149 / Chapter 5.1.15 --- Hydrogen peroxide content --- p.149 / Chapter 5.1.16 --- Microtox® test --- p.149 / Chapter 5.1.17 --- Amphipod survival test --- p.150 / Chapter 5.2 --- Biodegradation reaction --- p.151 / Chapter 5.2.1 --- Isolation of bacterial colonies --- p.151 / Chapter 5.2.2 --- Identification and characterization of the isolated bacteria --- p.151 / Chapter 5.2.3 --- Selection of cyanuric acid degrading species --- p.152 / Chapter 5.2.4 --- Effect of temperatures --- p.152 / Chapter 5.2.5 --- Effect of initial pH --- p.153 / Chapter 5.2.6 --- Effect of agitation rates --- p.153 / Chapter 5.2.7 --- Effect of cyanuric acid and glucose concentrations --- p.154 / Chapter 5.2.8 --- Glucose content --- p.154 / Chapter 5.2.9 --- Biodegradation metabolites of cyanuric acid --- p.155 / Chapter 5.2.10 --- Proposed degradation pathway of atrazine by biodegradation enhanced by PCO --- p.155 / Chapter 5.3 --- Integration of photocatalytic oxidation and biodegradation --- p.155 / Chapter 6 --- Conclusions --- p.159 / Chapter 7 --- References --- p.161 / Appendix1 --- p.174 / Appendix2 --- p.175

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 120-131). Also available online.

No description available.

Thesis (M.S.), Natural Resources, University of Wisconsin--Stevens Point, 2004. / Includes bibliographical references (leaves 43-47).