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Efeitos toxicológicos do glifosato
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Abstract(s)
O glifosato é um herbicida de largo espetro sintético e não seletivo, sendo mesmo o mais utilizado na agriculta para o controlo de ervas. O seu efeito herbicida advém de inibir uma enzima essencial no ciclo de vida das plantas, a 5-enolpiruvilchiquimato-3-fosfato sintase. Esta enzima participa na via chiquimato, uma via metabólica usada pelas plantas e algumas bactérias na síntese de folatos e aminoácidos. Visto que, esta enzima não está presente nos mamíferos, a utilização do glifosato tem sido referida como potencialmente segura.
Com a contaminação ambiental e a crescente sobredosagem, podem haver resíduos nos alimentos, no ar, solos e água. Foram realizados muitos estudos em que, se analisou o teor de glifosato nos alimentos e apesar destes não se encontrarem acima dos valores máximos estabelecidos de resíduos, a verdade é que, ainda não são claras as consequências a nível da saúde. Além disso, a exposição ambiental parece ter cada vez maior relevância.
Assim, e apesar de variadas agências reguladoras internacionais terem classificado o glifosato como seguro e não tóxico, a IARC classificou-o como potencialmente cancerígeno. Mais, vários cientistas têm vindo a estudar os efeitos deste composto a vários níveis, conforme abordado ao longo desta dissertação.
Nesta monografia fez-se uma revisão do estado de arte mais recente no que toca aos potenciais efeitos tóxicos do glifosato, em particular nos sistemas hepatorrenal, neurológico, cardiovascular e reprodutivo e os seus eventuais efeitos carcinogénicos e teratogénicos. Foram também abordadas as lesões e os sintomas encontrados no caso de intoxicações agudas.
Esta monografia contribui para uma integração atual dos estudos sobre os vários efeitos nocivos deste composto nos organismos, com os potenciais mecanismos de ação, e em estudos populacionais. São também apresentadas as limitações existentes e a necessidade de se incluírem metodologias mais rigorosas, nomeadamente nos estudos epidemiológicos, para se afirmar, com rigor e segurança a toxicidade do glifosato.
Glyphosate is a synthetic and non-selective broad spectrum herbicide, which have been mostly used in the agriculture for the control of herbs. Its herbicide effect comes from inhibiting an essential enzyme in the plants life cycle, the 5-enolpiruvilchiquimate-3-phosphate synthase. This enzyme participates in the chiquimate pathway, a metabolic pathway used by plants and some bacteria in the synthesis of folates and amino acids. Since this enzyme is not present in mammals, the use of glyphosate has been reported as potentially safe. There may be residues in food, air, soil and water with environmental contamination and increasing overdose. Many studies have been carried out in which the glyphosate content in food has been analysed and although these are not above the maximum established residue values, the fact is that the health consequences are still unclear. In addition, environmental exposure seems to be increasingly relevant. Thus, and although several international regulatory agencies have classified glyphosate as safe and non-toxic, IARC classified it as potentially carcinogenic. Moreover, several scientists have been studying the effects of this compound at various levels, as discussed throughout this dissertation. In this monography, a review of the most recent state-of-the-art regarding the potential toxic effects of glyphosate, in particular on the hepatorenal, neurological, cardiovascular and reproductive systems and its possible carcinogenic and teratogenic effects was made. The lesions and symptoms found in the case of acute intoxications were also addressed. This monography contributes to a current integration of studies on the various harmful effects of this compound on organisms, with potential mechanisms of action, and in population studies. The existing limitations and the need to include more rigorous methodologies, particularly in epidemiological studies, to affirm the toxicity of glyphosate with accuracy and safety are also presented.
Glyphosate is a synthetic and non-selective broad spectrum herbicide, which have been mostly used in the agriculture for the control of herbs. Its herbicide effect comes from inhibiting an essential enzyme in the plants life cycle, the 5-enolpiruvilchiquimate-3-phosphate synthase. This enzyme participates in the chiquimate pathway, a metabolic pathway used by plants and some bacteria in the synthesis of folates and amino acids. Since this enzyme is not present in mammals, the use of glyphosate has been reported as potentially safe. There may be residues in food, air, soil and water with environmental contamination and increasing overdose. Many studies have been carried out in which the glyphosate content in food has been analysed and although these are not above the maximum established residue values, the fact is that the health consequences are still unclear. In addition, environmental exposure seems to be increasingly relevant. Thus, and although several international regulatory agencies have classified glyphosate as safe and non-toxic, IARC classified it as potentially carcinogenic. Moreover, several scientists have been studying the effects of this compound at various levels, as discussed throughout this dissertation. In this monography, a review of the most recent state-of-the-art regarding the potential toxic effects of glyphosate, in particular on the hepatorenal, neurological, cardiovascular and reproductive systems and its possible carcinogenic and teratogenic effects was made. The lesions and symptoms found in the case of acute intoxications were also addressed. This monography contributes to a current integration of studies on the various harmful effects of this compound on organisms, with potential mechanisms of action, and in population studies. The existing limitations and the need to include more rigorous methodologies, particularly in epidemiological studies, to affirm the toxicity of glyphosate with accuracy and safety are also presented.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Glifosato Herbicida Efeitos toxicológicos Toxicologia