Distribuição de hidrocarbonetos policíclicos aromáticos nos sedimentos superficiais do manguezal do rio Estrela, baía de Guanabara, RJ, em função do vazamento de petróleo ocorrido em 2018

Abstract

The Estrela River is located between the municipalities of Duque de Caxias and Magé, flowing north into Guanabara Bay. On December 8, 2018, it was impacted by the leak of approximately 60 thousand liters of crude oil resulting from a leak in one of the Transpetro pipelines, the company responsible for transporting oil and gas. The banks of the Estrela River are colonized by mangroves, a coastal ecosystem of great importance for the maintenance of marine and terrestrial animals. This region has two conservation units, the Estrela Environmental Protection Area (APA) and the Barão de Mauá Municipal Park (PMBM). In order to determine the presence of PAHs in the surface sediment of the Estrela River mangrove forest due to the leak, samples were collected at 6 points between December 2018 and February 2019, shortly after the accident (Campaign I) and in December 2021 (Campaign II), therefore the research encompasses the sample period immediately after the accident and three years later. PAHs were identified and quantified using the gas chromatography coupled to mass spectrometry (GC-MS) method. In Campaign I, the presence of oil was determined in the location closest to the spill and in the other collection stations at the river's ebb, which can be explained by the preponderant transport of the river's flow. In Campaign II, the surface sediments of the Estrela River mangrove did not show clear signs of the oil from the 2018 accident, which can be attributed to several factors, such as washing of the surface sediment and oil percolation. Total PAH concentrations varied between 891 and 8,449 ng. g-1 immediately after the spill and remained between 414.14 and 814.30 ng. g-1 after 3 years. The set of data generated in both collections indicates that the Estrela River has a background of pyrolytic pollution, being classified as moderately contaminated. The importance of determining alkylated PAHs for the environmental assessment of the presence of petroleum and its derivatives is also concluded, since a toxic effect on biota was observed at the collection station closest to the spill in Campaign I and, even so, the Contamination levels, based on the sum of 16 USEPA HPAs, were considered moderate.