Desenvolvimento de dispositivo miniaturizado baseado em microextração em fase líquida para amostragem passiva de ésteres do ácido ftálico (PAEs) em lagoas marginais do Rio São Francisco

Abstract

Phthalic acid esters (PAEs), are emerging organic pollutants, widely used as plasticizers. PAEs are recognized as endocrine disruptors and potential carcinogens. They are also related to the decline of aquatic species populations and the emergence of dysfunctions in individuals and their genetic heredity, threatening the existence of endemic species or species in imminent risk of extinction. The use of miniaturized passive sampling techniques is convenient for the environmental monitoring of the PAEs, as, in addition to being more sensitive to temporal variations in the levels of the target pollutants when compared to the grab sampling modality, they require small amounts of material to generate statistically significant environmental information. Thus, in this work a miniaturized passive sampling device was developed based on liquid phase microextraction (LPME) technique with hollow fiber polypropylene membrane reinforced with nanocellulose. Morphological elucidation by X-Ray Diffraction (XRD) of the nanoparticles used in the reinforcement indicated cellulose II as the predominant allomorphic form. With the Fourier Transform Infrared Spectroscopy (FTIR) technique, it was possible to verify the formation of a composite (PP-CEL), whose presence was confirmed by thermal analysis techniques. Devices equipped with PP-CEL membranes were calibrated in dynamic mode through an automated calibration system designed to emulate the hydrodynamics of surface waters. First-order capture ranges were established between 30 minutes and 24 hours with sampling rates, Rs, equivalent to 0.009; 0.021; 0.033; 0.085 and 0.003 mL h -1 for DEP, DiBP, DBP, BBP and DEHP respectively (R 2 between 0.88 and 0.99). The calibrated devices were applied in the field in the equilibrium mode in twelve marginal lakes of the São Francisco River in the stretch located in the state of Minas Gerais, covering a distance of approximately 330 km along the river. The extracts recovered from the devices were analyzed by gas chromatography, obtaining the following combined concentration ranges: 0.697 – 13.67 ng L -1 DEP; 0.100 – 4.43 ng L -1 for DiBP and 0.014 – 1.21 ng L -1 for DBP isomer; 0.218 – 5.67 ng L -1 for BBP and 0.002 – 2.24 ng L -1 for DEHP. Despite being frequently found (loaded in >92% of samplers), DEHP was determined at levels well below the maximum limits established by control agencies, revealing a good water quality in the marginal lakes in relation to the target PAEs. On the other hand, a screening of extracts by GCxGC revealed the presence of another 209 substances, of which 150 were identified, including pollutants such as pesticides, drugs and their metabolites. The proposed device proved to be effective and reliable in providing the concentration of PAEs in water in short periods of exposure, suitable for emergency operations such as potential accidental discharges of industrial effluents into natural waters, piped or drinking water, therefore as a quick tool for evaluation of water quality, and mainly, a viable and economical alternative to grab sampling for the purposes of environmental monitoring.