Avaliação da correlação entre contaminação crônica e granulométrica das areias das praias brasileiras afetadas pelo derramamento de óleo em 2019

Abstract

In the second half of 2019, the northeastern coast of Brazil was affected by an oil spill, considered the largest environmental disaster in the country in terms of both extent and impact. The oil reached more than 4,000 km of coastline, directly affecting several states in the Northeast and Southeast regions. The aim of this study was to investigate the presence of possible polycyclic aromatic hydrocarbons (PAHs) in soil samples collected from beaches along the northeastern coast, using synchronous fluorescence spectroscopy associated with the PARAFAC model and granulometric analysis of the soils. In the extraction stage, the headspace technique was employed, using a heating block connected to a vacuum pump operating with four test tubes per run. Each tube was sealed with a screw cap containing a nylon membrane, and 2 mL of an acetonitrile–water solution (40:60 v/v) was added along with the soil sample. This condition increased the polarity of the medium, favoring the release of gases that, drawn by vacuum, passed through the membrane. For granulometric analysis, soil samples were subjected to wet and dry sieving, followed by weighing. The application of the PARAFAC model to the spectroscopic data enabled the deconvolution of three factors, with factor 1 identified as a pyrene-type compound and factor 3 as a phenanthrene-type compound, based on comparison with standard solution spectra. Granulometric results showed that most samples consisted predominantly of coarse or very coarse sand. Tabatinga Beach (A) was the only one that presented mesokurtic classification across all sand fractions and consistent presence of factor 1, while the other beaches showed different kurtosis classifications throughout the fractions. The results indicate that fluorescence spectroscopy combined with the PARAFAC model was effective in identifying fluorescent compounds, even at low concentrations and in the presence of natural interferences.