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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avalia??o do potencial genot?xico e citot?xico associado a queima artesanal da castanha de caju no Munic?pio de Jo?o C?mara

Galv?o, Marcos Felipe de Oliveira 14 October 2011 (has links)
Made available in DSpace on 2014-12-17T14:03:38Z (GMT). No. of bitstreams: 1 MarcosFOG_DISSERT.pdf: 3390000 bytes, checksum: ba6308b2ffb8a1c987acbb7748b9335f (MD5) Previous issue date: 2011-10-14 / The Brazil is the third largest producer of cashew nuts in the world. Despite the social and economic importance of the cashew nut, its production is still carried out artisanally. One of the main problems encountered in the cashew production chain are the conditions under which the roasting of the nut occurs to obtain the kernel from the shell. In the present study was conducted a biomonitoring of the genotoxic and cytotoxicity effects associated with the elements from the cashew nut roasting in Jo?o C?mara - RN, semi-arid region of Brazil. To assess the genotoxic was used the bioassay of micronucleus (MN) in Tradescantia pallida. In addition, it was performed a comparative between the Tradescantia pallida and KU-20 and other biomarkers of DNA damage, such as the nucleoplasmic bridges (NBP) and nuclear fragments (NF) were quantified. The levels of particulate matter (PM1.0, PM2.5, PM10) and black carbon (BC) were also measured and the inorganic chemical composition of the PM2.5 collected was determined using X-ray fluorescence spectrometry analysis and the assessment of the cytotoxicity by MTT assay and exclusion method by trypan blue. . For this purpose, were chosen: the Amarel?o community where the roasting occurs and the Santa Luzia farm an area without influence of this process. The mean value of PM2.5 (Jan 2124.2 μg/m3; May 1022.2 μg/m3; Sep 1291.9 μg/m3) and BC (Jan 363.6 μg/m3; May 70.0 μg/m3; Sep 69.4 μg/m3) as well as the concentration of the elements Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br and Pb obtained at Amarel?o was significantly higher than at Santa Luzia farm. The genotoxicity tests with T. pallida indicated a significant increase in the number of MN, NBP and NF and it was found a negative correlation between the frequency of these biomarkers and the rainfall. The concentrations of 200 μg/mL and 400 μg/mL of PM2.5 were cytotoxic to MRC-5 cells. All together, the results indicated genotoxicity and citotoxicity for the community of Amarel?o, and the high rates of PM2.5 considered a potential contributor to this effect, mainly by the high presence of transition metals, especially Fe, Ni, Cu, Cr and Zn, these elements have the potential to cause DNA damage. Other nuclear alterations, such as the NPBs and NFs may be used as effective biomarkers of DNA damage in tetrads of Tradescantia pallida. The results of this study enabled the identification of a serious occupational problem. Accordingly, preventative measures and better practices should be adopted to improve both the activity and the quality of life of the population. These measures are of fundamental importance for the sustainable development of this activity. / O Brasil ? o terceiro maior produtor mundial de castanha de caju e apesar da import?ncia social e econ?mica, sua produ??o ainda ? realizada de forma artesanal. Um dos maiores problemas da cadeia produtiva do caju s?o as condi??es nas quais ocorre a queima artesanal da castanha para se obter a am?ndoa. No presente estudo foi realizado um biomonitoramento do potencial genot?xico e avalia??o da citotoxicidade associada aos elementos oriundos da queima artesanal da castanha de caju no munic?pio de Jo?o C?mara - RN, semi-?rido brasileiro. Para a avalia??o genot?xica foi utilizado o bioensaio de micron?cleo (MN) em Tradescantia pallida. Al?m disso, foi realizado um comparativo quanto a sensibilidade da T. pallida frente ao clone KU-20 e outros biomarcadores de danos no DNA, tais como as pontes nucleoplasm?ticas (PNP) e fragmentos nucleares (FN) foram quantificados. A avalia??o citot?xica se deu pelo ensaio MTT e m?todo de exclus?o por tripan blue. As concentra??es de material particulado (MP1,0, MP2,5, MP10) e black carbon (BC) foram determinadas e a composi??o inorg?nica do MP2.5 definida pela t?cnica de fluoresc?ncia de raios-X. Foram definidos dois pontos testes: Comunidade do Amarel?o (local de queima da castanha de caju) e Fazenda Santa Luzia (sem influ?ncia da atividade). Os valores m?dios obtidos para o MP2,5 (Jan - 2124,2 μg/m3; Mai 1022,2 μg/m3; Set 1291,9 μg/m3) e BC (Jan 363,6 μg/m3; Mai 70 μg/m3; Set 69,4 μg/m3), bem como a concentra??o dos elementos Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br e Pb obtidos no Amarel?o foram significativamente maiores que na Fazenda Sta. Luzia. Os testes de genotoxicidade com T. pallida indicaram um aumento de 2-7 vezes maior na frequ?ncia de MN para o Amarel?o. Os outros biomarcadores tamb?m apresentaram sua frequ?ncia aumentada. Al?m disso, verificou-se uma correla??o negativa entre a freq??ncia de MN, PNP e FN com a precipita??o pluviom?trica. As concentra??es de 200 μg/mL e 400 μg/mL do MP2,5 em suspens?o foram citot?xicas para as c?lulas MRC-5. O conjunto dos resultados indicaram genotoxicidade e citotoxicidade para a comunidade do Amarel?o, sendo as altas concentra??es de MP2,5 um dos prov?veis contribuintes para esse efeito, principalmente pela elevada presen?a de metais de transi??o, sobretudo Fe, Ni, Cu, Cr e Zn, que potencialmente causam les?es no DNA. Outras altera??es nucleares, como PNP e FN podem ser utilizadas como biomarcadores efetivos de danos no DNA em t?trades de T. pallida. Os conjunto dos resultados possibilitaram a identifica??o de um problema ocupacional grave, com s?rios riscos aos trabalhadores que exercem a atividade. Diante disto, a ado??o de medidas preventivas e de melhores pr?ticas, s?o de fundamental import?ncia para o desenvolvimento sustent?vel da atividade e melhoria na qualidade de vida dos trabalhadores.

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