Bees provide important pollination services for crops and wild flowers, estimated to be valued at £120 billion to the global economy. However, declining bee populations have put these services in jeopardy. Pesticides are widely blamed, at least in part, for declines in both wild and managed bee species. Bees are exposed to dietary residues of pesticides when foraging on the nectar and pollen of treated bee-attractive crops. However, these residues are generally found at such low levels that it would not be feasible for a bee to ingest an acute lethal dose. Pesticides which exhibit time-reinforced toxicity could cause mortality to bees over an extended exposure period, though, as the damage they cause can increase exponentially over time. Currently, there is no test for time-reinforced toxicity included in bee risk assessments of pesticides. The overall aims of this thesis were to identify pesticides that exhibit time-reinforced toxicity and determine their effects on a range of demographically important sublethal endpoints in bees. Using a bioassay based on Haber’s Law, I identified fipronil as a pesticide exhibiting time-reinforced toxicity (TRT) in both the honey bee (Apis mellifera) and bumble bee (Bombus terrestris), from four widely-used candidate pesticides. Fipronil at field-relevant levels was found to significantly reduce the longevity and feeding of individual worker bumble bees and those in microcolonies. This nutrient limitation was postulated to be the cause of reduced fecundity of bumble bee microcolonies exposed to dietary fipronil at concentrations of 1 part per billion and less. The toxic effect of fipronil was dramatically increased when microcolonies were placed outside to forage for food, an effect documented by several other studies, and potentially due to an increase in metabolic rate from the need to fly. However, these effects were not observed in queenright Bombus terrestris colonies in the field. This disparity in effects may have been due to problems with exposure to fipronil rather than any possible resilience of colonies. The thesis findings highlight the need for time-reinforced toxicity testing in bees to be integrated into current risk assessment protocols for pesticides. My work in this thesis has provided validation for the use of the TRT bioassay in future risk assessments of pesticides. Current-use pesticides that exhibit TRT, in this case fipronil, pose a serious threat to both wild and managed bees, impacting on demographically important endpoints including feeding and reproduction. Further research, continuing on from the work in this thesis, is needed to ascertain the impacts of TRT pesticides at both colony and population levels. Determining the mechanisms of TRT pesticides will also be key to protecting bees from the danger they pose.

Contact mechanics of rough surfaces and surface wear will be considered. Two types of failures are considered. The first involving rapidly growing failure and the second fatigue type surface failure as a result of repetitive application of load cycle. The first type of failure will be identified based on surface hysteresis energy loss in a load/unload cycle or examination of fracture toughness of the material near its rough surface. The above approach will be used to examine both types of failure in joint implants in the human body. These include consideration of implants for hip, ankle, spine and knee. In this case rapid and/or fatigue failures will be considered and related to anticipated implant life cycle based on implant recipient's tolerance level. Hence surface fidelity in terms of the biological host's tolerance of toxicity level due to wear will be used to develop life cycle prediction of an implant. The second application, rapid and fatigue wear will be examined in commonly used mechanical systems that include spur and helical gearing and rolling element bearings.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Schinus terebinthifolius Raddi (Anacardiaceae) é uma espécie nativa da América do Sul com grande distribuição geográfica e muito comum em áreas de restinga. Sua grande plasticidade ecológica e boa interação biótica a torna espécie-chave na restauração de ambientes, porém, sua dominância pode estar relacionada à liberação de compostos alelopáticos. O objetivo do estudo foi avaliar o potencial alelopático dos extratos aquosos e óleos essenciais de folhas de Schinus terebinthifolius nas diferentes estações do ano sobre espécies-alvo nativas da restinga (Cereus fernambucensis, Erythroxylum ovalofolium, Pilosocereus arrabidae), uma espécie agrícola (Lactuca sativa) e nela própria (autoalelopatia). Para isso, suas folhas foram coletadas sazonalmente na restinga de Massambaba para o preparo dos extratos aquosos e extração dos óleos essenciais. Os extratos aquosos foram obtidos através da secagem das folhas a 60 C, trituração em liquidificador, diluição em água destilada e filtração, obtendo as concentrações de 5, 10, 15 e 20%. As extrações dos óleos foram realizadas através da hidrodestilação de 300 g de folhas frescas. A análise da composição dos óleos essenciais foi realizada através de cromatografia gasosa utilizando fibra SPME. O efeito fitotóxico foi avaliado nas espécies-alvo através da porcentagem de germinação, velocidade de germinação, crescimento aéreo e radicular, condutividade elétrica e massa seca. O efeito alelopático dos extratos aquosos foi observado em todas as espécies-alvo, principalmente sobre as espécies nativas. Esse efeito variou nas estações do ano de forma dose-dependente e espécie-específica. Os óleos essenciais de S. terebinthifolius também foram capazes de inibir a germinação e crescimento das espécies-alvo, e, da mesma forma que os extratos aquosos, esses efeitos variaram nas estações do ano e para cada espécie. Sugere-se que essas diferenças estejam relacionadas às fenofases de S. terebinthifolius e condições ambientais da restinga. Esse efeito fitotóxico, se comprovado em campo, pode restringir a utilização de S. terebinthifolius na restauração de ambientes. / Schinus terebinthifolius Raddi (Anacardiaceae) is a South America species with large geographical distribution, being common in Coastal Sandy Banks areas. Its ecological plasticity and good biotic interactions makes it a key specie in habitat restoring, but its dominance may be related to the release of allelopathic compounds. The objective of the study was to analyze the seasonal variation of Schinus terebinthifolius aqueous extracts and essential oils allelopathic effects on restinga target species (Cereus fernambucensis, Erythroxylum ovalofolium, Pilosocereus arrabidae), a crop species (Lactuca sativa) and itself (autotoxicity). For that, leaves were collected seasonally at restinga de Massambaba for aqueous extract preparation and essential oils extraction. Aqueous extract was obtained by drying the leaves at 60 C, grinding it in a blender, diluted with distilled water and filter, generating 5, 10, 15 and 20% concentrations. Oil extractions were performed by 300 g of fresh leaves hydrodistillation. Essential oil composition was performed by gas chromatography using SPME fiber. The phytotoxic effect was evaluated on germination percentage, speed of germination, hypocotyl and root growth, electrolyte leakage and dry mass of the target species. Aqueous extracts allelopathic effects were observed for all target species, especially for natives. Its effects varied with the seasons, being dose-dependent and species-specific. Schinus terebinthifolius essential oils could also inhibited target species germination and growth. Its effects varied with the seasons and target species. It is suggested that these differences are related to S. terebinthifolius phonological phases and restinga de Massambaba environmental conditions. This phytotoxic effect, if proven in the field, may restrict Schinus terebinthifolius use in habitat restoration

Engineered nanomaterials (ENMs) are specifically designed with different functionalities to satisfy required industrial, medical or commercial purposes. The inevitable release of these materials to the environment may impact negatively bacteria that are essential for the ecosystem’s well-being. This work aimed to identify features that determine the hazardous nature of nanomaterials to bacteria. At first, the bacterial growth inhibition concentrations for silver (Ag), cupric oxide (CuO), cadmium telluride quantum dots (CdTe QDs), titanium dioxide (TiO2), nanodiamonds and multi-walled carbon nanotubes were determined on Escherichia coli K-12 MG1655 grown in 96-well plates. The nano-forms of Ag, CuO, TiO2 and the CdTe QDs were found to display more growth inhibitory effects than their bulk equivalents. The metal salts of silver and copper were still more toxic than their equivalent ENM forms; on the contrary the CdTe QDs were found to be more toxic than their metal salts equivalent. The surface coatings of the ENMs were not found to be significant contributors of bacterial growth inhibition. This screening assay could be adapted as a first tier approach; providing an early input into the hazard assessment of nanomaterials to bacteria. The upscale determination of bacterial growth inhibition tests in 250 ml Erlenmeyer flasks manifested similar results to those observed in 96-well plates. The growth inhibition tests with E. coli were also conducted in an anaerobic fermentative environment. The presence of the ENMs was not found to disrupt the functionality of the fermentation respiratory pathway of the bacterium. However, the results indicated a more severe bacterial growth inhibition response to the presence of silver, copper and the cadmium/tellurium based ENMs as compared to the aerobic growth exposures. Finally, from the adaptation of a human ingestion simulation of soil containing CuO NPs, no greater concerns of metal bioaccessibility were identified from the potential ingestion of the nano-forms of CuO versus the metal salt.

Made available in DSpace on 2015-10-06T13:03:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-27. Added 1 bitstream(s) on 2015-10-06T13:18:36Z : No. of bitstreams: 1 000849993.pdf: 250584 bytes, checksum: ce29b95f47fab82e09fbb2be942af1ab (MD5) / Fipronil é um inseticida e acaricida altamente efetivo pertencente à família dos fenilpirazóis e ultimamente vem sendo extensivamente utilizado para combater infestações parasitárias tais como pulgas, formigas, cupins, carrapatos e piolhos de cães, gatos e bovinos. De acordo com relatos apresentados na literatura científica, existem casos de intoxicação hepática em mamíferos devido à sua exposição acidental ou utilização equivocada. O fígado desempenha função central no metabolismo, recebe nutrientes e xenobióticos que são por ele absorvidos, transformados, armazenados e liberados no sangue. A mitocôndria é responsável pela síntese de quase a totalidade do ATP necessário à manutenção da estrutura e função celular. Neste trabalho foram avaliados os efeitos do fipronil sobre a bioenergética de mitocôndrias isoladas de fígado de rato. Nas concentrações testadas (5 a 25 μM), o fipronil inibiu a respiração no Estado 3 da respiração em mitocôndrias energizadas com glutamato + malato, substratos do complexo I da cadeia respiratória, além de dissipar o potencial de membrana mitocondrial, acarretando a inibição da síntese de ATP pelas mitocôndrias. O efeito inibidor do fipronil sobre o complexo I foi confirmado pela inibição da atividade da enzima NADH desidrogenase. Esse efeito apresentado pelo fipronil sobre a bioenergética mitocondrial pode estar relacionado ao efeito tóxico apresentado pelo inseticida no fígado. / Fipronil is a highly effective insecticide and acaricide that belongs to the phenylpyrazole chemical family and it has been extensively used to control fleas, ticks and lice of dogs, cats and bovines.As reported by literature, there are intoxication cases due to the accidental exposure or mistaken fipronil application in mammals, it might affect including the liver that performs essencial functions related to metabolism, due to the liver receives nutrients and xenobiotics that are absorbed, converted, stored and released into the blood. The mitochondria is responsible for almost entirety ATP synthase required to maintaining cellular structure and function. In this paper were evaluated the fipronil effects on bioenergetic of isolated rat-liver mitochondria. In the tested concentrations (5 to 25 μM), the fipronil inhibited State III of respiration to mitochondria energized with glutamate + malate, complex I substrates of respiratory chain, besides dissipate mitochondrial membrane potential, resulting in mitochondrial ATP synthase inhibition. The fipronil inhibitor effect about the complex I was confirmed by the inhibiting enzyme NADH dehydrogenase activity. The effect presented by fipronil about the mitochondrial bioenergetic may be related to the toxic effect showed by the insecticide on liver

Submitted by João Leandro Chaguri null (joaoleandro@ibb.unesp.br) on 2016-04-12T17:43:06Z No. of bitstreams: 1 Dissertação João Leandro.pdf: 2543552 bytes, checksum: 518f71110e7d2f26f7fab66e56f7a3b7 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-13T18:42:12Z (GMT) No. of bitstreams: 1 chaguri_jl_me_bot.pdf: 2543552 bytes, checksum: 518f71110e7d2f26f7fab66e56f7a3b7 (MD5) / Made available in DSpace on 2016-04-13T18:42:12Z (GMT). No. of bitstreams: 1 chaguri_jl_me_bot.pdf: 2543552 bytes, checksum: 518f71110e7d2f26f7fab66e56f7a3b7 (MD5) Previous issue date: 2016-03-04 / O fipronil é um inseticida fenilpirazol amplamente utilizado na Medicina Veterinária, na agricultura e domesticamente para o controle de pragas. O mecanismo responsável pela sua ação tóxica consiste na inibição seletiva dos receptores do ácido gama amino butírico GABA associado a canais de cloreto. Estudos recentes mostram que fipronil afeta organismos não-alvo, incluindo populações de espécies ambiental e, potencialmente, os seres humanos. O presente estudo verificou se a exposição a fipronil afeta a pressão arterial sistólica e biomarcadores relacionados. Assim, fipronil foi administrado oralmente a ratos (30 mg / kg / dia) durante 15 dias (grupo Fipronil) ou solução fisiológica (grupo controle). Fipronil aumentou significativamente a pressão arterial sistólica (158 ± 13 mmHg), em relação ao grupo controle (127 ± 3 mmHg). Significativamente, níveis mais elevados de fipronil no plasma foram observados no grupo Fipronil (0,46 ± 0.09μg / mL contra 0,17 ± 0.11μg / mL no grupo de controle). O grupo exposto ao Fipronil apresentou ganho de peso menor em comparação com o grupo controle. Enquanto o fipronil resultou num aumento das concentrações de endotelina-1, a redução da capacidade antioxidante e níveis menores de metaloproteinase de matriz 2 (MMP-2) e Nitrito/Nitrato em relação ao grupo controle, não foram observadas alterações em marcadores séricos renal e hepáticos. Portanto, este estudo sugere que o fipronil provoca hipertensão e a endotelina-1 desempenha um papel importante. Além disso, estes resultados sugerem que as reduções de tanto a MMP-2 e NO podem contribuir com a elevação da pressão sanguínea sistólica observada com fipronil. / Recent reports show that fipronil affects non-target organisms, including environmental species populations and potentially humans. We aimed to examine if fipronil exposure affects the systolic blood pressure and related biomarkers. Thus, fipronil was orally administered to rats (30 mg/kg/day) during 15 days (Fipronil group) or physiological solution (Control group). While fipronil increased significantly the systolic blood pressure (158 ± 13 mmHg), no significant changes were observed in Control group (127 ± 3 mmHg). Significantly, higher levels of fipronil in plasma were observed in Fipronil group (0.46 ± 0.09 μg/mL versus 0.17 ± 0.11 μg/mL in Control group). Fipronil group showed lower weight gain compared with Control group. While fipronil resulted in higher concentrations of endothelin-1, reduced antioxidant capacity and lower levels of circulating matrix metalloproteinase 2 (MMP-2) and nitric oxide (NO) metabolites compared to Control group, no alteration was observed in serum biomarkers of renal and hepatic/biliary functional abilities. Therefore, this study suggests that fipronil causes hypertension and endothelin-1 plays a key role. Also, these findings suggest that reductions of both MMP-2 and NO may contribute with the elevation of systolic blood pressure observed with fipronil.

Made available in DSpace on 2014-06-11T19:26:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-25Bitstream added on 2014-06-13T19:54:06Z : No. of bitstreams: 1 schiavetto_ar_me_jabo.pdf: 1906023 bytes, checksum: f74f3d8916abc28806f1a1138918fa89 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com o objetivo de avaliar a tolerância de cultivares de cana-de-açúcar a misturas de herbicidas aplicados em pós-emergência inicial da cultura o experimento foi conduzido em área de produção comercial da Usina São Martinho, localizada no município de Pradópolis, SP. O estudo foi desenvolvido em campo no delineamento de blocos casualizados em esquema fatorial com 48 tratamentos em duas repetições. Os tratamentos foram constituídos pelas cultivares (RB855453; RB845257, SP90-3414, SP90-1638, SP89-1115; SP81-3250, IAC91-2218 e IAC91-5155) e pelos herbicidas T1=(sulfentrazone (500 g ha-1) + diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1); T2=metsulfuron-methyl (6 g ha-1) + sulfentrazone (750 g ha-1); T3=diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1) + clomazone (900 g ha-1); T4=metribuzin (1920 g ha-1) + diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1); T5=diuron (1599 g ha-1) + hexazinone (201 g ha-1) + MSMA (360 g ha-1); T6=ametryn (1097,25 g ha-1) + trifloxysulfuron-sodium (27,75 g ha-1) + diuron (702 g ha-1) + hexazinone (198 g ha-1)) e uma testemunha pareada para cada parcela. Os herbicidas foram aplicados sobre a palha oriunda da colheita da cana-de-açúcar em pré-emergência das plantas daninhas e pós-emergência inicial da cultura. Todas as parcelas mantidas na ausência de plantas daninhas durante todo período experimental. Cada parcela foi constituída por seis linhas, sendo uma central de meia parcela, tratada (TH); e a central da outra meia parcela, testemunha pareada (TP). As outras linhas foram bordaduras Foram avaliados aos 20 e 50 dias após aplicação (DAA) os sintomas visuais de fitointoxicação, o teor relativo de clorofila total e a razão de fluorescência da clorofila a; medições de altura foram feitas aos 30, 90 e 180 DAA e de estande aos 30, 90 e 180 DAA. Por ocasião da colheita aos 210 DAA foram avaliados o diâmetro dos colmos, os teores... / The experiment was conducted sugarcane commercial area from Sao Martinho will in Pradópolis, SP, in order to evaluate the tolerance of sugarcane cultivars to the association of herbicides applied post-emergence culture. The study was conducted in the field in a randomized block design in factorial with 48 treatments in two replications. The treatments consisted of cultivars (RB855453, RB845257, SP90-3414, SP90-1638, SP89-1115, SP81-3250, and IAC91-2218 IAC91-5155) and the herbicide T1=(sulfentrazone (500 g ha-1) + diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1); T2=metsulfuron-methyl (6 g ha-1) + sulfentrazone (750 g ha-1); T3=diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1) + clomazone (900 g ha-1); T4=metribuzin (1920 g ha-1) + diuron (842,4 g ha-1) + hexazinone (237,6 g ha-1); T5=diuron (1599 g ha-1) + hexazinone (201 g ha-1) + MSMA (360 g ha-1); T6=ametryn (1097,25 g ha-1) + trifloxysulfuron-sodium (27,75 g ha-1) + diuron (702 g ha-1) + hexazinone (198 g ha-1)) and a paired control for each plot. Herbicides were applied over the straw coming from the crop of sugarcane in pre-emergence weed and post-emergence of the crop, all plots being maintained in the absence of weeds throughout the experimental period. Which plot was formed by 6 rows of sugarcane. The central one of each 3 rows were used as treated (TH) and paired control (TP). The other rows were borders. Were evaluated at 20 and 50 days after application (DAA) visual symptoms, total chlorophyll and the ratio of chlorophyll a fluorescence; height measurements were made at 30, 90 and 180 DAA and stand at 30, 90 and 180 DAA. At harvest at 210 DAS were evaluated for stem diameter, the brix, purity, pol, sugars (AR) in the juice, cane fiber, total sugar recovered (ATR) and production of the stems (t ha-1). The mean difference, TP-TH, was subjected to the t tests, using the hypothesis of the difference with zero... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:32:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-05Bitstream added on 2014-06-13T20:03:11Z : No. of bitstreams: 1 arantes_vp_dr_arafcf.pdf: 859243 bytes, checksum: a63861f6840c16a5e57c201c6982bb42 (MD5) / Universidade Estadual Paulista (UNESP) / As plantas medicinais sempre desempenharam papel importante na medicina, e modernamente, ainda são capazes de incrementar o arsenal terapêutico, fornecendo esperança de melhores condições de tratamento para inúmeras doenças. A Tuberculose (TB) é considerada a principal causa de morte em países em desenvolvimento, de grande população e baixo padrão sanitário. O objetivo do presente trabalho foi avaliar a toxicidade oral aguda e a médio prazo dos extratos vegetais de Syngonhanthus macrolepsis, Turnera ulmifolia e Quassia amara, em ratos. Para avaliação da toxicidade foram utilizados os protocolos 401 e 408 da “Organization for Economic Cooperation and Development” (OECD). Ênfase foi dada as alterações do perfil bioquímico e histopatológico de fígado e rins. Utilizando Kits avaliou-se a atividade da ALT, AST, γ-GT, ALP, além de uréia, creatinina, bilirrubina e tempo de protrombina. Os cortes de fígado e rins foram corados com hematoxilina e eosina e analisados em microscopia óptica. Mesmo quando se administrou 5000mg/kg, apenas alguns animais apresentaram piloereção e irritabilidade que não alcançaram 8 horas, caracterizando assim baixa toxicidade aguda. Para toxicidade a médio prazo as alterações mais significantes em relação aos respectivos controles foram os níveis de creatinina para o extrato de T. ulmifolia. Na avaliação da toxicidade a médio prazo observou-se que o extrato de T.ulmifolia apresentou maior toxicidade em comparação aos respectivos controles. As fêmeas foram mais sensíveis que os machos tanto para as análises de função renal quanto hepática. Em geral as fêmeas apresentaram maior toxicidade que os machos. Assim, considerando as DNEAO ao nível renal e hepático, tendo com “end point” alterações bioquímicas que foram as mais sensíveis, para as fêmeas seria 200Pg/mL e para os machos 400Pg/mL, gerando RfD respectivamente... / The medicinal plants had always played important role in the medicine, and modernly, still are capable to develop the therapeutical armory, supplying hope of better conditions of treatment to innumerable illnesses. The Tuberculosis (TB) is considered the main cause of death in underdeveloped countries, great population and low sanitary condition. The objective of the present work was to evaluate the acute oral toxicidade and subchronic oral toxicity of vegetal extracts of Syngonhanthus macrolepsis, Turnera ulmifolia and Quassia amara in rats. For evaluation of the toxicity protocols 401 and 408 of the “Organization and Development will be Economic Cooperation” (OECD) had been used. Emphasis was given to the changes in the biochemist and histopathologic profile of liver and kidneys. Using Kits it was evaluated activity of the ALT, AST, γ-GT, ALP beyond urea, creatinina, bilirubin and prothrombin time. The cuts of liver and kidneys had been dyed with hematoxylin and eosin and analyzed in light microscopy. Even though when 5000mg/kg bw was given, only some animals had presented heir stand and irritability that had not later than 5h, having thus characterized low acute toxicity. For subchronic toxicity, the most significant changes in relation to the respective controls had been the levels of creatinina for the extract of T. ulmifolia. In the evaluation of the subchronic toxicity it was observed that the extract of T.ulmifolia presented greater toxicity in comparison to the respective controls. The females had been more sensible than the males as well hepatic as renal function. In general the females had presented greater toxicity that the males. Thus, considering the NOAEL to the renal and hepatic level, having with end point biochemical changes who had been most sensible, for the females would be 200Pg/mL and for the males 400Pg/mL which , generating RfD respectively of 17,5 and 35mg/kg... (Complete abstract click electronic access below)

abstract: Engineered nanoparticles (NP; 10-9 m) have found use in a variety of consumer goods and medical devices because of the unique changes in material properties that occur when synthesized on the nanoscale. Although many definitions for nanoparticle exist, from the perspective of size, nanoparticle is defined as particles with diameters less than 100 nm in any external dimension. Examples of their use include titanium dioxide added as a pigment in products intended to be ingested by humans, silicon dioxide NPs are used in foods as an anticaking agent, and gold or iron oxide NPs can be used as vectors for drug delivery or contrast agents for specialized medical imaging. Although the intended use of these NPs is often to improve human health, it has come to the attention of investigators that NPs can have unintended or even detrimental effects on the organism. This work describes one such unintended effect of NP exposure from the perspective of exposure via the oral route. First, this Dissertation will explain an event referred to as brush border disruption that occurred after nanoparticles interacted with an in vitro model of the human intestinal epithelium. Second, this Dissertation will identify and characterize several consumer goods that were shown to contain titanium dioxide that are intended to be ingested. Third, this Dissertation shows that sedimentation due to gravity does not artifactually result in disruption of brush borders as a consequence of exposure to food grade titanium dioxide in vitro. Finally, this Dissertation will demonstrate that iron oxide nanoparticles elicited similar effects after exposure to an in vitro brush border expressing model of the human placenta. Together, these data suggest that brush border disruption is not an artifact of the material/cell culture model, but instead represents a bona fide biological response as a result of exposure to nanomaterial. / Dissertation/Thesis / Doctoral Dissertation Biology 2014

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-27T13:12:58Z No. of bitstreams: 1 NAIARA ÂNGELO GOMES - DISSERTAÇÃO (PPGECA) 2017.pdf: 2054177 bytes, checksum: b38a4c9f046028dc334d619defff13e3 (MD5) / Made available in DSpace on 2018-07-27T13:12:58Z (GMT). No. of bitstreams: 1 NAIARA ÂNGELO GOMES - DISSERTAÇÃO (PPGECA) 2017.pdf: 2054177 bytes, checksum: b38a4c9f046028dc334d619defff13e3 (MD5) Previous issue date: 2017-03-03 / Capes / O aterro sanitário é a técnica de disposição final de resíduos sólidos urbanos mais utilizada no mundo. No entanto, devido à complexidade do processo de degradação biológica que ocorre no interior das células de resíduos, são gerados os líquidos lixiviados, que em função de serem efluentes tóxicos, heterogêneos e com uma composição bastante variada e complexa, podem causar toxicidade à saúde pública e ao meio ambiente. Assim, o objetivo deste trabalho foi analisar o potencial tóxico do lixiviado gerado em uma célula do Aterro Sanitário localizado em Campina Grande, Paraíba. O experimento consistiu em coletar quinzenalmente, durante os meses de junho a novembro do ano de 2016, amostras de lixiviado in natura em um poço de visita que recebia todo o líquido efluente gerado pela célula estudada. Após as coletas, o lixiviado foi caracterizado por meio de ensaios físico-químicos (pH, alcalinidade total, ácidos graxos voláteis, cloretos, demanda química de oxigênio, nitrogênio amoniacal total e metais pesados) e toxicológico (fitotoxicidade). Além disso, fez-se ainda, uma análise estatística dos dados obtidos durante o período de monitoramento. Os resultados demonstraram que em condições ácidas de pH, o lixiviado apresentou elevadas concentrações de ácidos graxos voláteis, demanda química de oxigênio e metais, em especial, ferro, manganês e cromo, os quais foram os principais elementos a ocasionarem fitotoxicidade às sementes de tomate (Solanum lycopersicum) e de repolho (Brassica oleraceae). Contudo, quando o pH do lixiviado tendeu para valores entre a neutralidade e a basicidade, as concentrações dos metais analisados tiveram um decaimento, reduzindo, dessa forma, o potencial de toxicidade do lixiviado em relação aos metais. Porém, durante esse período, foram determinados os maiores teores de nitrogênio amoniacal total, mas, devido ter prevalecido no lixiviado o nitrogênio na forma de íon amônio, esse componente, provavelmente, não conferiu toxicidade as referidas sementes. Conclui-se que, o lixiviado apresentou um maior potencial fitotóxico na fase de degradação ácida, e, com a evolução do processo de biodegradação dos resíduos depositados na célula analisada, os ensaios de fitotoxicidade evidenciaram um lixiviado com uma menor carga tóxica. / Sanitary landfilling is the most widely used final disposal technique for municipal solid waste in the world. However, due to the complexity of the biological degradation process inside the waste mass, the leachate liquid are generated. The leachate requires special attention, because it is a toxic, heterogeneous effluent with a very varied and complex composition; can cause promote toxicity to health public and the environment. In this context, this work aimed to analyze the toxic potential of leachate generated in a landfill cell in Campina Grande – State of Paraiba, Brazil. The experiment consisted of collecting samples of fresh leachate (biweekly from June to November of 2016) in a well that received all the liquid generated by the landfill cell studied, from the landfill of Campina Grande. After collection, the leachate was characterized by physical-chemical (pH, total alkalinity, volatile fatty acids, chlorides, chemical oxygen demand, total ammonia nitrogen and heavy metals) and toxicological (phytotoxicity) analyses. In addition, the correlations between these parameters were verified. The results registered that in acidic conditions of pH, the leachate presented high concentrations of volatile fatty acids, biochemical demand of oxygen and metals (especially iron, manganese and chromium). These were the main factors causing phytotoxicity of tomato (Solanum lycopersicum) and cabbage (Brassica oleraceae) seeds. However, when the pH of the leachate tended to be between neutral and basic, the concentrations of the analyzed metals decreased, reducing the toxicity potential of the leachate in relation to the metals. Even so, during this period, the highest levels of total ammoniacal nitrogen were obtained. Because nitrogen in the form of ammonium ion prevailed in the leachate, this component probably did not infer toxicity to plant seeds. It can be concluded that the leachate presents a higher phytotoxic potential in the acid degradation phase. With the evolution of the biodegradation process of the residues deposited in cell studied, despite the high levels of ammoniacal nitrogen measured, the phytotoxicity tests evidenced a leachate with a lower toxic load.