Hidrocarbonetos policíclicos aromáticos decorrentes do derramamento de óleo no Nordeste: caracterização e estimativa do risco ecológico no estuário do Rio Cocó

Abstract

Polycyclic aromatic hydrocarbons, considered persistent organic pollutants, is one of the classes that make up oil. In the second half of 2019, coastal ecosystems of the Brazilian Northeast suffered the greatest environmental impact in national history, caused by the oil spill. Thus, the present work aims to determine PAHs associated with the superficial sediment of the Sabiaguaba beach strip, and the estuarine zone of the Cocó River, determine their levels, distinguish natural from anthropic sources, as well as estimate the ecological impact caused by these compounds. Seven points were chosen, three of them on the beach strip and four with estuarine predominance. The sediments were freeze-dried, tested using different eluotropic fractions, followed by ultrasound-assisted extraction, concentrated to 1mL, and the extracts were cleaned up for analysis by gas chromatography coupled to a mass spectrometer (GC-MS). Through the GC-MS technique, levels of PAHs were quantified in the samples, with the sum of concentrations ranging from 1.089 to 197.49 ng.g-1, levels similar to other literatures, being considered little impacted. For source estimation, ratios of low molecular weight PAHs over high molecular weight PAHs were used, in addition to ratios between some isomer pairs (ANT/178; FL/202; BeA/228 and Ind/276), the results pointed to pyrolytic sources, due to the detection of 4-6 ring PAHs in the samples, suggesting biomass burning contribution. National (CONAMA) and international (CCME and NOAA) guides were used for ecological impact assessment, where low potential risk to biota was shown.