Intratidal variability and transport of petroleum aromatic hydrocarbons in an anthropized tropical estuarine system: the Suape estuary (8.4S 35W)

Abstract

The Suape Estuary encompasses the Suape Industrial Port Complex (SIPC), a major industrial development in Brazil's Northeast region, which, in order to be implanted, caused drastic environmental changes in this system. This study presents the first physical characterization of the Suape estuarine system, focusing on the local hydrodynamics, material transport and its influence on some specific properties. Physical properties were also associated to dissolved dispersed petroleum hydrocarbons (DDPHs). A study was undertaken during a complete semi-diurnal tidal cycle (13 hr), during which water level, water flow, current velocity and direction, water properties (salinity, temperature, suspended particulate matter - SPM -, chlorophyll and dissolved oxygen) were recorded using ADCP and CTD systems. The DDPHs were investigated in surface and bottom waters, by spectrofluorescence, using Carmópolis oil and chrysene as analytical standards. Results showed a well-mixed vertical structure, a semi-diurnal tide regime and a diurnal thermal pattern. There was no statistical difference between DDPH concentrations at surface and bottom, due to the tide acting as an important homogenizer. DDPHs were low and the main contribution seems to be that from SIPC, as the residual transport of DDPHs, chlorophyll and dissolved oxygen, was towards the Massangana estuary. An opposite pattern was observed for salinity and SPM, whose residual transport was towards the lagoon. The results pointed local hydrodynamics as an essential tool for understanding material transport and exchanges among the estuarine segments. A longer time series should be studied in order to obtain more robust conclusions.

Petroleum hydrocarbons in Brazilian Northeast continental shelf waters: baseline values

“…What catches the eye at first glance are the highest values off Suape in both periods, suggesting that large ship navigation activity in the vicinity of Suape Port is likely the main source of petroleum hydrocarbons. In fact, such contribution has already been reported elsewhere (Lemos et al, 2014;Zanardi-Lamardo et al, 2018). Interestingly, higher concentrations also occurred at outer shelf stations during winter.…”

“…PAHs, individually or expressed as total concentration (dissolved / dispersed petroleum hydrocarbons -DDPH), have been reported in water and sediments from many Brazilian estuaries and bays (e.g., Todos os Santos Bay by Venturini and Tommasi, 2004; Patos Lagoon by Medeiros et al, Zanardi-Lamardo and Schettini 2005; Guanabara Bay by Silva et al, 2007;Cocó and Ceará estuaries by Cavalcante et al, 2009;Santos Estuary by Martins et al, 2011;Arruda-Santos et al, 2018). Assessments were also made near oil industry hotspots as harbors (São Sebastião channel by Zanardi et al, 1999a;b;Silva and Bícego, 2010;Lemos et al, 2014;Maciel et al, 2015a;Zanardi-Lamardo et al, 2018) and offshore extraction zones (Potiguar basin by Wagener et al, 2011) or open waters (South West Atlantic waters, Bícego et al, 2002). This study presents the very first assessment on dissolved / dispersed petroleum hydrocarbons (DDPH) on the eastern sector of the Brazilian Northeast region, off Pernambuco State in open waters on the continental shelf.…”

“…This system has also high trapping capacity (Schettini et al, 2016a), but the higher loads of pollutants discharged in its lower stretch can effectively export material to the adjacent shelf (Maciel et al, 2016;Schettini et al, 2016b). Another potential coastal source is the Suape Estuary, located ~50 km south of Recife, where a major industrial and harbor development started in the mid-1980s (Lemos et al, 2014;Zanardi-Lamardo et al, 2018).…”

“…Water samples were liquid-liquid extracted according to previous studies (Lemos et al, 2014;Zanardi-Lamardo et al, 2018). In brief, 20 mL of nhexane (pesticide grade) was added to the 4 L amber glass bottle immediately after water sampling.…”

“…Considering that oil is a complex mixture, the use of chrysene as a standard (IOC, 1984) has raised some disagreement among researchers although it has been accepted because it provides a worldwide basis for comparison of results. On the other hand, Carmópolis oil comes Hydrocarbon in Brazil's Northeast shelf waters Zanardi-Lamardo and Schettini from one of the oldest active oil fields along the northeastern coast of Brazil, and it has been widely used as a standard oil for the Brazilian coast, southwestern Atlantic and western Antarctic Peninsula (Zanardi et al, 1999a;b;Bícego et al, 2002;2009;Lemos et al, 2014;Maciel et al, 2015b;Arruda-Santos et al, 2018;Zanardi-Lamardo et al, 2018). Field blank samples and internal standard recovery (surrogate) were used for quality control purposes.…”