Banca de DEFESA: THAYANE CRISTINA DA SILVA MOREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : THAYANE CRISTINA DA SILVA MOREIRA
DATE: 28/07/2023
TIME: 09:00
LOCAL: Auditório do Depto. de Química/UFRPE
TITLE:

EVALUATION OF ENVIRONMENTAL CONTAMINATION ON THE COAST OF PERNAMBUCO AFTER OIL SPILLS IN 2019

KEY WORDS:

Hydrocarbons, oil spill, contamination, seawater, sediment.

PAGES: 132
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Análise de Traços e Química Ambiental
SUMMARY:

In August 2019, the largest environmental disaster involving an oil material spill in Brazil occurred. This material contaminated much of the northeastern coastline, including the state of Pernambuco, which triggered the immediate importance of assessing the level of contamination and the impact on the environment by compounds of the classes of aliphatic hydrocarbons (HAs) and polycyclic aromatic hydrocarbons (PAHs), some considered toxic compounds, with carcinogenic, mutagenic, and teratogenic potential. This study aimed to perform the chemical characterization of 50 samples of seawater and marine sediments collected in seasonal periods (summer and winter) on the coast of the state of Pernambuco in the year 2021 to perform the identification and quantification of HAs and PAHs to assess the level of contamination of the coastal aquatic system of Pernambuco after the 2019 oil spills, using the analytical techniques of fluorescence spectroscopy and gas chromatography-mass spectrometry. In addition, measurements of classical analyses (grain size, organic matter, and elemental analysis) and physicochemical parameters (pH, temperature, dissolved oxygen, conductivity, and salinity) of the collected samples were performed. For the seawater samples, the results of the physicochemical parameters showed a seasonal influence, differentiating the samples collected in the summer period from those collected in the winter. Furthermore, it was possible to identify and quantify 17 PAHs, of which naphthalene was the predominant one, while the diagnostic ratios were able to classify the contamination of some seawater samples by petrogenic and pyrogenic sources, with a classification between micropolluted and slightly polluted. As a highlight, the risk quotient results (RQ_MPCs) showed that the sample P20 (summer), located in Barra de Sirinhaém-PE, presented high environmental risk, and the ecotoxicity data showed three samples (P08 and P20 - summer and P11 - winter, located in Boa Viagem, Barra de Sirinhaém and Paiva, respectively) classified as toxic, corroborating what was obtained in the application of principal component analysis (PCA). For the sediment samples, the results obtained from the physicochemical parameters showed that all samples presented organic matter characteristic of higher plants and algae, besides a predominance of sandy fractions. Method validation by solid-liquid extraction and GC-MS analysis allowed the quantification of HAs in the C11 to C36 range, which through diagnostic ratios, indicated sources of petrogenic contamination in some samples. Furthermore, it was possible to identify and quantify 15 PAHs, which through absolute concentrations and diagnostic ratios were able to classify the level of contamination of the sediment samples in a low to high degree, indicating petrogenic and pyrogenic sources in the sedimentary MO studied. Finally, the RQ_MPCs results pointed out some sediment with high environmental risk, which were confirmed by the ecotoxicity assay, which showed five samples with lethal effects and eighteen with sublethal effects. Thus, it was possible to infer that some regions of the coastal aquatic system of Pernambuco presented a relevant contamination level for some of the studied compounds, with possible contamination coming from the 2019 spill, being this the first study that evaluated the levels of environmental contamination simultaneously in sea waters and sediments. Thus, it is expected that the results obtained can help agencies responsible for the preservation and recovery of the state's coastline, encouraging the continuity of studies in the affected regions, also considering that there was a new oil spill event in the year 2022.

COMMITTEE MEMBERS:
Presidente - JANDYSON MACHADO SANTOS
Interno - MARCILIO MARTINS DE MORAES
Externa à Instituição - LAIS ARAUJO SOUZA - UFPE