Desenvolvimento e validação de metodologia para determinação de bisfenol A e ftalatos em amostras de chorume por GC-MS

Abstract

The landfill leachate is characterized by high concentration of organic matter, ammonia and toxic compounds. This effluent, found in dumps and controlled landfills, comes from the decomposition of urban waste and when added to the rainwater carries the organic compounds present in the waste to the environment. Currently in Brazil, Law n o . 12.305 / 2010 is in force, which required the extinction of landfills and controlled landfills until August 2014. Two years after the final deadline of the decree, the country still uses controlled landfills and landfills for final disposal of urban solid waste, being still a socio-environmental problem. The composition of the landfill leachate results from the decomposition of many organic and inorganic chemical compounds, which makes the landfill leachate a complex matrix of analysis. In this work, a methodology was developed and validated using hollow fiber liquid phase microextraction (HF-LPME) and gas chromatography coupled to mass spectrometry (GC-MS) for the determination of bisphenol A (BPA) and of phthalates in landfill leachate. These compounds have been chosen because they are associated with the production of plastic materials and because they are endocrine disrupters (EDs), that is, they deregulate the hormonal system of animals and humans. The optimization of the method was done through a fractional design with the variables extraction time, agitation, pH, addition of salt and temperature for the selection of significant variables. A Doehlert design was constructed to determine the optimum conditions by the response surface of the experimental domain. After the optimization stage, the method was validated with the main merit figures. The linearity was evaluated in the concentration range of 0.25 to 30.0 μg L -1 obtaining coefficients of determination for all analytes above 0.998. Detection limits ranged from 0.15 to 0.76 μg L -1 . For intra-assay and inter-assay precision studies coefficients of variation were obtained from 1.9% to 10.9%. In the recovery studies, values between 77.7% and 113% were found, which indicates the adequate performance of the HF-LPME for extraction of the analytes. The proposed method is simple, efficient and uses minimal amounts of organic solvents. After the validation the method was applied for the determination of BPA and phthalates in the landfill leachate samples from the controlled landfill of Divinópolis, Minas Gerais, where the presence of diethyl phthalate, BPA and bis- (2-ethylhexyl) phthalate was verified. The landfill leachate samples were collected at three different points of the controlled landfill and concentrations of BPA up to 804 μg L -1 were found. Brazil does not yet have legislation regarding the disposal of BPA in the environment, but according to the European Union Risk Assessment Report concentrations above 11 μg L -1 present acute toxicity in aquatic bodies. The results of this work bringing us an alert about the risks of exposure of living beings in the region of the controlled landfill.