Avaliação da contaminação ambiental por hidrocarbonetos do petróleo em sedimentos do rio Ipojuca, Caruaru, Pernambuco, Brasil

Abstract

The hydrographic basin of the Ipojuca River, in the state of Pernambuco, Brazil, is about 320 km long and includes 25 municipalities, one of which is the city of Caruaru, which is a municipality of regional importance, representing approximately 2.43% of the state GDP. In the region, the river is used for leisure, fishing, human, agricultural, and industrial supply, and may be exposed to several contaminants, including those from the use of petroleum derivatives. Therefore, it is extremely important to evaluate the level of contamination and the impact caused to these aquatic environments, through the identification with geochemical biomarkers, aiming to identify the compounds of the classes of aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs), which are considered bioaccumulative and toxic and may have carcinogenic and mutagenic potential. The present study aimed to carry out the chemical characterization of ten surface sediment samples collected from the Ipojuca River, in the stretch related to the municipality of Caruaru/PE, in order to identify and quantify HAs and PAHs, to obtain the level of contamination of the aquatic system. The HAs were detected with carbon numbers from C15 to C37, which, through diagnostic ratio calculations, such as the preferential carbon index (PCI), indicated contamination sources of petrogenic and biogenic origin in the sediments. The isoprenoids pristane (Pr) and phytane (Ft) were also identified in all sediments, where the Pr/Ft ratio pointed to contamination referring to the presence of petroleum hydrocarbons. For PAHs, it was possible to identify and quantify 21 compounds, which, according to the absolute concentration values and through the diagnostic ratios, could classify the contamination level of the field sediments in a moderate to a high degree, indicating petrogenic and pyrogenic sources in the formation of organic matter in the sediments. Thus, it was possible to infer that the studied aquatic system is with a relevant contamination level for the studied compounds. Thus, it is expected that the results obtained can help agencies responsible for the preservation and recovery of the Ipojuca River.