The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.

Philosophiae Doctor - PhD / The overall aim of this thesis was to prepare nanostructured more processable heteronuclear sulphonated polyanyline nanocomposites with electroconductive properties suitable for applications in biosensors. The sulphonated self-assembled polyaniline and derivatised polyaniline nanocomposites (SPAHs) were prepared by chemical oxidative polymerisation or electrical decomposition. The SPAHs prepared include those of polyaniline (PANi), poly-o-methoxyaniline (POMA) and poly-2.5 dimethoxyaniline (PDMA). Two types of sulphonic acids of heteronuclear aromatic hydrocarbons were used in the production of sulphonated SPAH composites. These were anthracene sulphonic acid (ASA) and naphthalene sulphonic acids (NSA) wich played both doping and surfactant roles. / South Africa

Extensive use of the organophosphate diazinon has led to its accumulation in aquatic environments and negative effects on fish health. Most studies focus on the effects of short term exposure to high levels of organophosphate pesticides. This research was conducted to assess the effect of chronic sub-lethal exposure to 0, 0.01, and 0.1 mg/L diazinon for 15 and 30 days on blood parameters and histopathological damage in alligator gar, Atractosteus spatula. Fish exposed to either concentration were motionless, produced excess mucous, had lighter skin color, and had skin lesions. Blood indices of red blood cells, leukocytes and hematocrit values significantly decreased but there was no significant change in mean cell volume. Hemoglobin values significantly increased in fish exposed to the low dose for 15 days, but significantly decreased for the other exposure doses and times. On the contrary, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration values significantly increased in fish exposed to both concentrations and duration times. Leukocyte differentials showed significant decreases in lymphocytes with significant increases of monocytes in fish exposed to the high dose in both exposure times. The most frequent biomarker for exposure to organophosphate pesticides is the inhibition of cholinesterase (ChE). Diazinon significantly reduced plasma ChE activity in a dose-dependent manner, with 62% and 72% in the low and high concentrations for 30 days, respectively. Plasma ChE could be determined from peripheral blood samples and did not require sacrifice of the fish. Fish exposed to either diazinon concentration or duration time developed histopathological changes in skin, gills, liver, and kidney tissues. The skin lesions were on the head and body, and progressed into deep ulcerations. The histopathological changes in the liver included hepatic vacuoles, swollen hepatocytes, steatosis, aggregation of macrophages, necrosis, and hepatic fibrosis. Also, exposed fish demonstrated vacuolar degeneration in the hematopoietic tissues of the kidney. Gills showed epithelial hyperplasia in the secondary lamellae. In conclusion, long term exposure to sub-lethal concentrations of diazinon induced significant changes in hematological indices and histopathological alteration in various tissues. Plasma ChE can be used to monitor diazinon exposure in wild gar populations.

Orientador: Eduardo Alves de Almeida / Banca: Maria Aparecida Marin Morales / Banca: Glória Elisa Florido Mendes / Resumo: Os contaminantes ambientais são relevantes no contexto ecotoxicológico devido a seus efeitos citotóxicos e carcinogênicos nos organismos não-alvos. A análise de biomarcadores bioquímicos constitui uma ferramenta eficiente nos estudos de avaliação de risco e impacto ambiental, pois conseguem realizar a detecção precoce dos efeitos nos organismos em virtude da exposição aos poluentes ambientais. O Brasil está entre os maiores consumidos de agrotóxicos do mundo e nesse contexto destacam-se os compostos organofosforados (OP) e carbamatos (CA). Neste trabalho foram analisadas em brânquias, fígado e tecido nervoso da tilápia Oreochromis niloticus e do cascudo Pterygoplichthys anisitsi após 2 e 7 dias, a atividade das enzimas acetilcolinesterase (AChE), carboxilesterase (CbE), glutationa S-transferase (GST), glutationa peroxidase (GPx), 7- etóxiresorufina-O-deetilase (EROD), e peroxidação lipídica como candidatos a biomarcadores bioquímicos sensíveis à contaminação por diazinon (OP) e carbaril (CA). A morfologia do fígado dos cascudos foi avaliada após 7 dias de exposição aos pesticidas, em fragmentos de tecidos corados com HE. A exposição aos pesticidas causou significativa inibição da AChE e CbE nas duas espécies; aumento significativo da GST no fígado dos cascudos expostos ao OP , no fígado e brânquias das tilápias expostas ao CA e nas brânquias dos cascudos expostos ao CA; inibição da EROD no fígado das duas espécies expostas ao OP e tendência à ativação nas duas espécies expostas ao CA; tendências à diminuição dos níveis de malondialdeído e aumento da GPx no fígado nas duas espécies. Os cascudos expostos ao OP mostraram aumento na taxa de núcleos hipercromáticos e esteatose, e em ambas as exposições os cascudos apresentaram aumento no diâmetro do núcleo dos hepatócitos, sendo mais acentuado pelo composto CA. Estes resultados... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Environmental contaminants are ecotoxicologically relevant due to their cytotoxic and carcinogenic effects in non-targets organisms. The analysis of biochemical biomarkers is a powerful tool in studies of risk assessment and environmental impact, because it can achieve early detection of the effects on organisms as a result of exposure to environmental pollutants. Brazil is among the largest world consumers of pesticides, including organophosphates and carbamates. In this work, after 2 and 7 days of the treatment, the activity of the enzymes acetylcholinesterase (AChE), carboxylesterase (CbE), glutathione S-transferase (GST), glutathione peroxidase (GPx), ethoxyresorufin-O-deethylase (EROD) and lipid peroxidation were analyzed in gills, liver and nervous tissue of tilapia Oreochromis niloticus and armoured catfish Pterygoplichthys anisitsi, as candidates of sensible biochemical biomarkers of contamination by diazinon (OP) and carbaryl (CA). The morphology of the liver of the armoured catfishes was examined after 7 days of exposure to pesticides, in fragments of tissue stained with HE. Exposure to pesticides caused significant inhibition of AChE and CBE in the two species, significant increase in GST in the liver of armoured catfishes exposed to OP, in the liver and gills of tilapia exposed to CA and the gills of armoured catfishes exposed to CA, EROD inhibition in the liver of both species exposed to OP and a trend of activation in both species exposed to CA, and trends to decreased levels of malondialdehyde and increased GPx in the liver in both species. The catfishes exposed to OP showed increased rate of hyperchromatic nuclei and steatosis, and both armoured catfishes showed increase in the diameter of the nucleus of hepatocytes, being more accentuated by the armoured catfishes exposed to CA. These results suggest the usefulness of the activity of AChE, CBE, GST and morphological... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:22:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-15Bitstream added on 2014-06-13T19:08:30Z : No. of bitstreams: 1 rodrigues_acf_me_sjrp.pdf: 796473 bytes, checksum: 478bd32abee6cd2efceb78698757085b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os contaminantes ambientais são relevantes no contexto ecotoxicológico devido a seus efeitos citotóxicos e carcinogênicos nos organismos não-alvos. A análise de biomarcadores bioquímicos constitui uma ferramenta eficiente nos estudos de avaliação de risco e impacto ambiental, pois conseguem realizar a detecção precoce dos efeitos nos organismos em virtude da exposição aos poluentes ambientais. O Brasil está entre os maiores consumidos de agrotóxicos do mundo e nesse contexto destacam-se os compostos organofosforados (OP) e carbamatos (CA). Neste trabalho foram analisadas em brânquias, fígado e tecido nervoso da tilápia Oreochromis niloticus e do cascudo Pterygoplichthys anisitsi após 2 e 7 dias, a atividade das enzimas acetilcolinesterase (AChE), carboxilesterase (CbE), glutationa S-transferase (GST), glutationa peroxidase (GPx), 7- etóxiresorufina-O-deetilase (EROD), e peroxidação lipídica como candidatos a biomarcadores bioquímicos sensíveis à contaminação por diazinon (OP) e carbaril (CA). A morfologia do fígado dos cascudos foi avaliada após 7 dias de exposição aos pesticidas, em fragmentos de tecidos corados com HE. A exposição aos pesticidas causou significativa inibição da AChE e CbE nas duas espécies; aumento significativo da GST no fígado dos cascudos expostos ao OP , no fígado e brânquias das tilápias expostas ao CA e nas brânquias dos cascudos expostos ao CA; inibição da EROD no fígado das duas espécies expostas ao OP e tendência à ativação nas duas espécies expostas ao CA; tendências à diminuição dos níveis de malondialdeído e aumento da GPx no fígado nas duas espécies. Os cascudos expostos ao OP mostraram aumento na taxa de núcleos hipercromáticos e esteatose, e em ambas as exposições os cascudos apresentaram aumento no diâmetro do núcleo dos hepatócitos, sendo mais acentuado pelo composto CA. Estes resultados... / Environmental contaminants are ecotoxicologically relevant due to their cytotoxic and carcinogenic effects in non-targets organisms. The analysis of biochemical biomarkers is a powerful tool in studies of risk assessment and environmental impact, because it can achieve early detection of the effects on organisms as a result of exposure to environmental pollutants. Brazil is among the largest world consumers of pesticides, including organophosphates and carbamates. In this work, after 2 and 7 days of the treatment, the activity of the enzymes acetylcholinesterase (AChE), carboxylesterase (CbE), glutathione S-transferase (GST), glutathione peroxidase (GPx), ethoxyresorufin-O-deethylase (EROD) and lipid peroxidation were analyzed in gills, liver and nervous tissue of tilapia Oreochromis niloticus and armoured catfish Pterygoplichthys anisitsi, as candidates of sensible biochemical biomarkers of contamination by diazinon (OP) and carbaryl (CA). The morphology of the liver of the armoured catfishes was examined after 7 days of exposure to pesticides, in fragments of tissue stained with HE. Exposure to pesticides caused significant inhibition of AChE and CBE in the two species, significant increase in GST in the liver of armoured catfishes exposed to OP, in the liver and gills of tilapia exposed to CA and the gills of armoured catfishes exposed to CA, EROD inhibition in the liver of both species exposed to OP and a trend of activation in both species exposed to CA, and trends to decreased levels of malondialdehyde and increased GPx in the liver in both species. The catfishes exposed to OP showed increased rate of hyperchromatic nuclei and steatosis, and both armoured catfishes showed increase in the diameter of the nucleus of hepatocytes, being more accentuated by the armoured catfishes exposed to CA. These results suggest the usefulness of the activity of AChE, CBE, GST and morphological... (Complete abstract click electronic access below)

Wetland wastewater treatment offers low-cost, energy efficient alternatives to conventional wastewater technologies. In this study, an artificial wetland was constructed at the City of Denton, Texas Pecan Creek Water Reclamation Plant to facilitate diazinon removal from treated effluent.