Distribution and Sources of Aliphatic and Polycyclic Aromatic Hydrocarbons in Surface Sediments of Itajaí-Açu Estuarine System in Brazil

Abstract

The Itajaí-Açu estuarine system, located in southern Brazil, has great economic importance due to the presence of two ports (Itajaí and Navegantes). This system is affected by industrial and dredging activities, which can cause the remobilization of pollutants accumulated over time in the sediment. In this context, hydrocarbons were assessed in twelve surface sediment samples. n-Alkane and polycyclic aromatic hydrocarbons (PAH) concentrations were determined by gas chromatography and their sources assessed. Total concentrations ranged between 0.50 ± 0.04 and 69.70 ± 3.90 µg g -1 dry weight (d.w.) for n-alkanes and from 63.9 ± 12.1 to 1459.0 ± 43.5 ng g -1 d.w. for PAH. Most of the sediment samples presented carbon preference index (CPI) values close to unity, indicating that the area is submitted to petroleum-related sources, mainly close to Itajaí harbor, where an intense unresolved complex mixture (UCM) was observed. The presence at all stations of aβ-hopane biomarkers also indicated petrogenic input. Based on selected PAH ratios, the sedimentary PAH composition reflects a mixture of both petrogenic and pyrolytic sources. A comparison of the PAH concentrations found in this study with those listed in the sediment quality guidelines (SQGs) indicated that adverse biological effects on the biota are rarely expected.Keywords: aliphatic hydrocarbon, polycyclic aromatic hydrocarbon, biomarker, hopane, contamination IntroductionContamination levels in coastal environments are increasing mainly due to the presence of anthropogenic activities, as waste industrial discharges, industrial activities, navigation traffic, etc.1 Therefore, sediment contamination in such areas may occur. In several countries, port activities are rapidly developing, requiring greater attention, especially in relation to the dredging of contaminated sediments and environmental management. 2,3The Itajaí-Açu estuarine system is located on the north-central coast of Santa Catarina state, in Brazil. This is an area of economic interest not only because of tourism, but also due to the presence of the Port of Itajaí, which is considered the third largest container handling port in Brazil, the major international trading point of the state, and the largest national fishing pole landing site. Associated with this latter activity, several fish processing industries are installed along the margins of this estuary, mainly in the city of Itajaí. These industries dispose their waste products, usually without any treatment, directly into the estuary. [4][5][6][7] In addition, the harbor area is constantly dredged, in order to maintain the navigation channel at an elevation of 11 meters. In May 2011, dredging began to deepen the main river channel, aiming to increase the depth from 11 to 14 meters, allowing the entrance of larger ships. Sediment dredging can cause remobilization of the pollutants accumulated in this compartment over time. 6 O r g a n i c c o m p o u n d s s u c h a s a l i p h a t i c hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (P...

Assessment of Aliphatic Hydrocarbons in Sediments of Shatt Al-Arab River, Southern Iraq, North East Arabian Gulf

“…Shatt Al-Arab river is subject to hydrocarbons pollution by sewage, industrial wastes and the activities of refining in addition to natural seeps and other human activities (Farid et al, 2016). The concentrations of n-alkanes measured here are relatively within the range of many other worldwide oil contaminated sediments such as those reported by Bouloubassi et al (2001), Yunker et al (2003), Lee et al (2005), Mille et al (2007), Zaghden et al (2007), Harji et al (2008), Da Silva and Bicego (2010), Wang et al (2011), Wagener et al (2012, Punyu et al (2013), Zrafi et al (2013) and Frena et al (2017). The comparison also reveal higher sedimentary concentrations of n-alkanes in Shatt Al-Arab River compared to those detected by Readman et al (2002), Medeiros and Bicego (2004), Medeiros et al (2005), Tolosa et al (2005), Wang et al (2006), Gao et al (2007) and Harji et al (2008).…”

“…8). The tricyclic terpanes and tetracyclic terpanes are observed at all sediments which are found in crude oil and fossil fuel (Frena et al, 2017). The extended 17α,21β-hopane series (C31-C35) occur as 22S and 22R epimers ( Fig.…”

“…The pristane (pri) and phytane (phy) are originated from geologic alteration of phytol and other isoprenoidyl products (Frena et al, 2017). They are usually present in most petroleum as major constituents and are considered as common indicators for petroleum pollution.…”

“…Therefore, the sediments can be considered as a major reservoirs of pollutants because of their ability to retain organic compounds (Zrafi et al, 2013). The sediments analysis gives a lot of information about the pollutants sources, digenetic processes and extent of pollution in the environment (Frena et al, 2017). Hydrocarbons such as n-alkanes are commonly utilized to evaluate the oil pollution origins in the aquatic environment due to the ease of their analysis and most of it have specific sources (Punyu et al, 2013).…”

A Química Ambiental no Brasil nos 40 anos da SBQ

“…113 Hidrocarbonetos aromáticos (HPA) e alifáticos (n-alcanos) têm sido determinados frequentemente em ambientes aquáticos doces e estuarinos, em todo o território nacional, com a aplicação de estratégias voltadas para a determinação das fontes de contaminação. [114][115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130] Em outros casos, as determinações de HPA têm sido realizadas visando a avaliação de alterações em ecossistemas aquáticos, em particular nos sedimentos. 129,131,132 Outras classes de contaminantes orgânicos, como os poluentes orgânicos persistentes (POP) também têm sido estudados em ambientes aquáticos.…”