Avaliação da ecotoxicidade e biodegradação da ametrina em meio líquido

• Autor(a) principal: Mártires, Giulia Malaguti Braghini Marcolini
• Data de Publicação: 2019
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/218057
• topic: Ametryn; Respirometry; Gesapax® Ciba Geigy; Biodegradation; Ecotoxicity; Biodegradação; Ecotoxicidade; Ametrina; Biorremediação; Respirometria

With the expansion of sugarcane culture in Brazil and especially in the state of São Paulo, the use of agrochemicals such as pesticides, fungicides and herbicides has increased. These can eventually be carried to rivers or aquifers. The persistence of pesticides in the environment can lead to ecosystem destabilization, promoting detrimental effects on human health and other species. Ametryn is the active ingredient in Gesapax® CIBA GEIGY, one of the most widely used herbicides in monocultures in Brazil. For the treatment of herbicide contaminated environments, the use of microorganism bioremediation techniques has been increasing. It is possible to select native soil microbial consortia that are adapted to the degradation of specific contaminants, to use for decontamination. Biodegradation activity can be measured by the respirometry technique, which quantifies the release of CO2 and consume of O2, making it possible to analyze the efficiency of bioremediation in treating a contaminated environment. The objective of this work was to study the biodegradation of ametryn in liquid medium, assuming the contamination of rivers and groundwater. For this, the method of respirometry based on the studies of Bartha & Pramer (1965) was used, with the aid of mathematical modeling to adjust the results. Also, to verify the effects of ametryn on plant growth, ecotoxicity tests were performed from the germination of lettuce and arugula seeds in the presence of herbicide. Additionally, conductivity and pH were measured to enable comparison of physical parameters in situations before and after the biodegradation process. As a result, it was possible to conclude the biodegradation efficiency, since the full consumption of the contaminant was observed in the period of 70 to 80 days. Ametryn showed itself non-toxic or with signs of toxicity in relation to lettuce seeds and was considered toxic in relation to arugula seeds. Conductivity and pH tests provided further evidence of the success of ametryn biodegradation.