Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e Matematicas. Curso de Pós-Graduação em Físico-Química / Made available in DSpace on 2012-10-15T22:26:45Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-08T14:29:25Z : No. of bitstreams: 1 104438.pdf: 1034274 bytes, checksum: efa620e3011ebc2013d3c3ecee346b4b (MD5) / As reações de decomposição básica dos 1-ari1-2,2,2-tricloroetanóis em meio aquoso foram estudadas em função da concentração de hidróxido e da temperatura. A velocidade de formação dos benzaldeídos a partir dos etanóis correspondentes mostrou um aumento até alcançar um patamar a altas concentrações de hidróxido. Os parâmetros de ativação para a decomposição dos etanóis foram determinados a partir de corridas cinéticas efetuadas a 25, 30, 35 e 40°C. O comportamento cinético é compatível com um mecanismo E1cB. Foram determinadas as constantes K e k2 de pré-equilíbrio e constante limite da velocidade no patamar respectivamente para todos os etanóis. Os valores dos pKa's dos etanóis foram comparados com valores para análogos 1-aril-2,2,2-trifluoretanóis e 1,1-diaril-2,2,2-tricloroetanóis.

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This thesis describes the creation of substituted diphenylacetic acids and their results.

The fate and transport of insoluble, hydrophobic organic pollutants in the aquatic environment constitutes a prominent area of concern. It is thought that pollutants of this nature may exist in association with organic carbon, which is predominantly aquatic humus. This type of association could significantly affect the kinetics of such transformation processes as volatilization or chemical and biological degradation of the pollutant. While dissolved organic matter (DOM) comprises the bulk of organic carbon (or aquatic humus) in natural waters, the interaction between naturally occurring DOM and insoluble organic pollutants has not been quantified. The work presented in this dissertation is an effort to quantify the effect of dissolved organic matter on the solubility in water and, hence, the transport of hydrophobic organic compounds (specifically, DDT) in the environment. Saturated aqueous solutions of DDT were generated by a method that is different from those used by other workers. Within a closed system, an excess of solid DDT was allowed to vaporize and enter an aqueous solution through the gas phase. The concentration of DDT in solution increased with time, leveling off when equilibrium and a saturated solution was established. The solubility of p,p'-DDT in distilled water was determined to be 1.87 (+OR-) .01 ppb. The solubility of the o,p'-DDT isomer in distilled water was determined to be 4.88 (+OR-) .03 ppb. The concentrations of p,p'-DDT and o,p'-DDT in distilled water solutions containing dissolved organic matter were definitely higher than the aqueous solubilities of these compounds. A minimum value for the DDT/DOM partition coefficient (K(,p)) in water was determined. This partition coefficient, when normalized to organic carbon, is referred to as K(,oc) (K(,oc) = K(,p)/fraction organic carbon). A minimum log K(,oc) for both p,p'-DDT and o,p'-DDT was determined to be 4.7 (+OR-) .2 log units. Under environmental conditions, this partition coefficient indicates that the majority of DDT present in aqueous systems will be associated with dissolved organic matter.

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Last page is titled: Appendix 1: DVD of Model Simulations (See DVD in Back Envelope). There was no DVD present for upload. / <p>Point Pelee National Park (PPNP), located in Leamington, Ontario, Canada experienced widespread application of DDT from 1950 until DDT was banned in Canada in 1970. vVbile DDT has not been applied at PPNP for over 30 years recent studies have shown that the compounds DDT, ODE and DDD are highly persistent in shallow soils at PPNP and often exceed regulatory guidelines set forth by the Ontario Ministry of the Environment and Environment Canada. Field study combined with numerical modelling was undertaken to assess the concentrations of DDT, DDE and DDD in groundwater and provide insight into the fundamental processes controlling the persistence and migration of DDT within former agricultural areas of PPNP. Results of one-dimensional pesticide fate and transport modelling from 1950 to 2003 using LEACHMP show that within former agricultural areas of PPNP, DDT is transformed primarily not DOE under aerobic conditions. Within the Camp Henry Orchard (CHO), half lives for the production of DDE are 30 years. LEACHMP modelling showed that adsoption was the most important process limiting DDT leaching to groundwater. The depth to the water table was found to influence DDT concentrations seen at the water table throughout former agricultural areas of PPNP, and DDT is most likely leaching to the water table slowly over time. Two dimensional saturated zone modelling using OW-WETLAND was used to test various loading scenarios based on LEACHMP simulated fluxes across the water table. Model outputs illustrated the bidirectional movement of contaminants toward both the marsh and Lake Erie, depending on the source location relative to the groundwater flow divide. Simulations showed only groundwater from deep within the aquifer would have elevated DDT concentrations in 2003 if DDT leached to groundwater between 1950 and 1970. Conversely, if DDT began to leach to groundwater in the 1990's, the model predicted that DDT was not present in deep groundwater in 2003. With continued loading, concentrations throughout the aquifer will continue to rise into the future and discharge of DDT to the marsh and Lake Erie will occur.</p> / Thesis / Master of Science (MSc)

The ecological role of chironomids has been described as an abundant and ubiquitous prey item for not only aquatic species, but terrestrial and avian species as well. Global use of pesticides in urban and agricultural applications have introduced a potential threat not only to chironomid populations, but to the individuals that prey on chironomids. Chironomids direct contact with the sediment has resulted in both legacy and current-use pesticides being detected in the individuals throughout their life cycle. The capacity for contaminant uptake and biotransformation among each midge life stage and from larvae to adults, however, is poorly understood. The lipophilic compounds of focus for this thesis include bifenthrin, and p,p’-DDT, along with the biotransformation products, TFP acid, BP alcohol, BP acid, p,p’-DDE and p,p’- DDD. To observe bioaccumulation and biotransformation at each life stage (2nd,3rd,4th, pupae, and adult), month long exposures were run with a subset of individuals being removed at each life stage and processed to quantify total, parent, and biotransformation product concentrations. Exposures at low concentrations (below literature C. dilutus no observable adverse effects concentration) at 25°C produced mean C. dilutus total pesticide concentrations ranging from 36.31 to 896.1 μg/kg dw lipid for bifenthrin and from 41.64 to 877.7 μg/kg dw lipid for DDT through all life stages. The 3rd instar contained the highest parent bifenthrin concentration, though this concentration was not statistically different from the concentration in the pupae. The 3rd instar also contained the highest parent concentration of DDT, though concentrations were not statistically different from concentrations in 2nd to 3rd instar larvae. C. dilutus also displayed subsequent biotransformation of DDT to DDE in each instar. By the 4th instar, 87.10% of the total concentration in the midges was DDE and DDD. The biotransformation of DDT to DDD was also observed to occur in sediments and was likely due to direct reductive dechlorination through chemical processes. Chironomid uptake of DDD increased as the parent DDT was degraded to DDD in the sediments over the testing period. This study provides a greater understanding of the bioaccumulation and biotransformation potential in chironomids at each life stage. Initial spiking concentrations were too low, resulting in low body residues and with no method detection limit or reporting limit defined for the study, so these lower measures have limited certainty. Therefore, the implications of this thesis are limited.

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