2,4,6-trinitrotoluene (TNT) is of environmental concern because it?s a possible human carcinogen and it also remains potentially explosive. The Department of the Army (DA) estimates that there are 540,000 cubic meters (700,000 cubic yards) of explosives-contaminated soil at over 2,000 sites that require remediation. Biological treatment of TNT results in the production of the reduced intermediates (such as aminonitrotoluenes). When using chemical oxidation processes to treat TNT, 1,3,5-trinitrobenzene (TNB) is produced. The by-products of both biological and oxidation treatment processes are resistant to further treatment thus they require extensive treatment times. This study evaluated the use of biotic mechanisms that can be used to reduce TNT into aminodinitrotoluenes, which then are oxidized using Fenton?s Reagent oxidation process. Integration experimental results showed that Fenton?s Reagent was capable of degrading TNT, though not as fast as ADNTs. The optimal Fe2+/H2O2 ratio appears to be less than 10:1. The TNT biodegradation rate was higher than the TNT oxidation rate and was biodegraded at a faster rate compared to the ADNTs. It was concluded that the integrated technology showed promise as an effective and innovative technology for treating TNT contaminated soil.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 136-146). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Robin Gerlach. Includes bibliographical references (leaves 146-152).

Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 258-264).

Made available in DSpace on 2014-06-12T15:52:16Z (GMT). No. of bitstreams: 2 arquivo4515_1.pdf: 709397 bytes, checksum: 32ca7a05bac132d3232f3cc45576b1ac (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As determinações da troponina cardíaca T (TnT) podem contribuir para o diagnóstico e tratamento de infarto agudo do miocárdio e para a estratificação dos riscos dos pacientes com síndromes coronárias agudas no que respeita ao risco relativo de mortalidade. Neste trabalho, um sistema de microbalança de quartzo por injeção de fluxo baseado na alteração de freqüência elétrica em resposta à ligação antígeno-anticorpo foi empregado para determinação da TnT cardíaca. As variações de freqüências foram registradas por um contador de freqüência acoplado a um microcomputador. O anticorpo monoclonal específico foi imobilizado sobre a superfície de um eletrodo de cristal de quartzo por ligação irreversível via monocamadas auto-organizadas. O adsorbato composto por filme de alcanotiól foi formado incubando uma solução de 2-aminoetanotiol (cisteamina) por 2 h, seguido por glutaraldeído a 2,5% (v/v). Em seguida, anticorpos monoclonais anti- troponina T (anti-TnT) foram covalentemente imobilizados sobre o eletrodo de ouro do cristal de quartzo e foi usada uma solução de glicina (10mM) como agente bloqueante. Com o imunossensor desenvolvido foi possivel medir concentrações de troponina T com limite de detecção de 0,025 ng/mL. A superfície do sensor pode ser regenerada por injeção de uma solução do dodecil-sulfato de sódio 1% (p/v). A determinação da TnT foi realizada em amostras de soros humanos permitindo seu uso nas aplicações clínicas para diagnóstico do IAM

The nitroaromatic explosive 2,4,6-trinitrotoluene is a widespread, toxic groundwater contaminant. The objective of this work was to describe TNT fate in contaminated aquifer sediments. A series of bench scale experiments and model simulations were performed to evaluate the fate of TNT in historically contaminated aquifer sediments. A TNT contaminated site on the National Priorities List, Former Nansemond Ordnance Depot (FNOD), Suffolk, VA, served as the model site for this work. To describe desorption rate in contaminated sediments, two approaches for a first order single-site desorption were evaluated. In Model 1, the driving force for desorption is mathematically related to the sorbed phase concentrations, whereas in Model 2 the rate is based on aqueous phase concentrations. Two data sets were used to evaluate the models: (1) batch draw-and-fill experiments using FNOD sediment and (2) results from a previously published report from the Louisiana Army Ammunition Plant. Both models provided adequate fit, but Model 2 was better behaved and first order parameters fell within a smaller confidence interval. Draw-and-fill experiments were observed to yield first-order mass transfer coefficients well aligned with those derived from column experiments. The effect of organic amendments on anaerobic TNT degradation rate and microbial community structure in culture enriched from the FNOD site was studied in batch anaerobic microcosms. TNT readily degraded under all experimental conditions. A reductive pathway of TNT degradation was observed across all conditions, however, denaturing gradient gel electrophoresis (DGGE) analysis revealed distinct bacterial community compositions. In all microcosms, Gram-negative γ- or β-Proteobacteria and Gram-positive Negativicutes or Clostridia were observed. According to non-metric multidimensional scaling analysis of DGGE profiles, the microcosm communities were most similar to field site sediment corresponding to the highest TNT concentration, relative to moderately and uncontaminated sediments, suggesting that TNT contamination itself is a major driver of microbial community structure. Candidate degraders were identified and a Pseudomonas sp. was observed to be stimulated under all conditions, which was confirmed to rapidly degrade TNT in pure culture. Mathematical modeling of the batch microcosm results revealed that TNT degraded 1.7 times faster in lactate amended microcosms than in ethanol amended microcosms, which degraded 3.0 times faster than natural organic matter amended microcosms. Simulation of the TNT degradation pathway included determination of branching coefficients representing whether the first reduction of nitro group occurred in the ortho or para position or whether TNT was removed from the aqueous phase (i.e. bound to dissolved organic matter). Branching coefficients were greater for initial reduction of para (17-27% initial TNT concentration) over ortho (3-9% initial TNT concentration) for all test conditions. However, a greater degradate recovery and a different (lower para/ortho) ratio was observed for ethanol compared to lactate and un-amended conditions. Given the difference in sorption parameters between degradate isomers, these results suggest that differences in pathway branching stimulated by different electron donors are potentially relevant to long term site models. This work provides parameter values and model simulations of desorption relevant to other TNT contaminated sites, qualitative observations of how TNT-reducing bacterial community structure changes in response to electron donor addition, and quantitative comparison of the effect of electron donor addition on biodegradation rate with cultures relevant to field conditions; in addition, this work serves as a feasibility study demonstrating biodegradation as well as biostimulation potential at FNOD. / Ph. D.

Residues of 2,4,6-trinitrotoluene (TNT) in soil and groundwater near former production and processing plants generate large environmental concerns. A cyclodextrin (CD) mediated Fenton remediation of TNT contaminated water and sand (soil analogy) is presented. Kinetic studies were performed to elucidate the role of cyclodextrin in Fenton remediation of TNT contaminated water. The rate and extent of TNT degraded by Fe2+- CD-H2O2 systems were significantly enhanced as compared to the classic Fenton method. Further, in water system with interfering substance - humic acid, which tends to associate with TNT, the addition of cyclodextrin helped to improve the efficiency of Fenton degradation. This technique has also been successfully applied to remediate TNT contaminated soil systems (sand). Four systems were investigated: clean sand, sand and humic acid, sand and fulvic acid, sand and natural organic matter. This technique has shown superior performance than classic Fenton method in all of the four above systems.

Nitroaromatic explosives, such as trinitrotoluene (TNT), are of particular environmental concern due to their recalcitrance in soils and their potent toxicity and mutagenicity to both aquatic and mammalian species. TNT was the most widely used military explosive through the era encompassing both the First and Second World Wars. As a result, there is widespread contamination of soils by TNT around weapons manufacture, testing, and disposal facilities. Fenton chemistry (ferrous ion catalyzed generation of hydroxyl radicals) has shown utility in the remediation of TNT in soils but it suffers from non-specificity and the need for acidic conditions to prevent loss of iron as iron hydroxides. Cyclodextrins (CDs) have demonstrated the ability to increase the efficiency of Fenton degradation of aromatic pollutant species. The increase in degradation efficiency observed in the CD Fenton reaction systems has been credited to the formation of a pollutant/CD/ferrous ion ternary complex which has the ability to produce hydroxyl radicals at the site of bound ferrous ions during Fenton reactions. This results in an increase in hydroxyl radical concentration near the target guest molecule relative to the bulk solution, leading to a targeted degradation of the complexed guest molecule. In order to assess the viability of CD assisted Fenton reactions for the remediation of TNT, a thorough knowledge of the kinetics, degradation products, and role of binary and ternary complexes is required. Research presented in this dissertation examined the role of CDs in the Fenton oxidation of TNT, specifically: 1) the kinetics of TNT degradation in the presence of CDs for a Fenton reaction system, 2) the products of these reactions through chromatographic and mass spectrometric methods, and 3) NMR and binding studies of binary and ternary complexes.

<p>A bioslurry reactor was built for the bioremediation of TNT contaminated waste from the demilitarization industry. The field test was conducted at Vingåkersverken in Vingåker, Sweden, to see if results from laboratory studies could be repeated in a full scale reactor. The goal of the project was to optimize the reactor to such a degree that it could be used to handle the waste produced at Vingåkersverken and also that this technique could be applied for remediation of contaminated soils. Unfortunately the samples taken during the full scale field test were destroyed by the shipping company and no analysis was possible. A later attempt by the Biorex research group has also been unsuccessful to reduce the amount of TNT using the bioreactor. How are we going to reach the results from the laboratory studies? The work continues.</p>