The key role played by the Augusta basin (southern Italy) in the mercury contamination of the Mediterranean Sea

Abstract

The Augusta basin, located in SE Sicily (southern Italy), is a semi-enclosed marine area, labelled as a highly contaminated site. The release of mercury into the harbour seawater and its dispersion to the blue water, make the Augusta basin a potential source of anthropogenic pollution for the Mediterranean Sea. A mass balance was implemented to calculate the HgT budget in the Augusta basin. Results suggest that an average of ∼0.073 kmol of HgT is released, by diffusion, on a yearly basis, from sediments to the seawater, with a consequent output of 0.162 kmol y(-1) to coastal and offshore waters; this makes the Augusta area an important contributor of mercury to the Mediterranean Sea. Owing to the geographical location of the Augusta basin, its outflowing shelf-waters are immediately intercepted by the surface Atlantic Ionian Stream (AIS) and mixed with the main gyres of the eastern Mediterranean Sea, thus representing a risk for the large-scale marine system.

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

“…5). In particular, the highest HgT mean concentrations occur in fishes caught from southern Augusta Bay where bottom sediments show the highest concentrations of mercury (Sprovieri et al, 2011) (Fig. 1).…”

“…A direct comparison of HgT content in benthic species from Augusta Bay and other Mediterranean areas affected by comparable Hg discharges by chlor-alkali plant and sewage sludge disposal, specifically Tuscany and Israel (Hornung et al, 1980;Gibičar et al, 2009), show 2-7 times higher values, thus, underlying the combined effects of high pollution levels and specific biogeochemical pathways driving mercury bioavailability in the studied system (Table 2). Sprovieri et al (2011) and Fantozzi et al (2013) have argued on a potential Hg export from Augusta Bay to the Eastern Mediterranean seawater, as a result of the measured 3D circulation system. Nonetheless, Hg contamination detected in sediments outside of Augusta Bay, by effects of dredged material from the inner bay (Di Leonardo et al, 2008;Tranchida et al, 2010), could also directly influence the state of pollution of the open sea.…”

“…Sprovieri et al (2011) reported high-resolution maps of HgT distribution from superficial sediments collected in 2005, highlighting extremely high concentrations (ranging between 0.1 and 527.3 mg kg À1 ) and speculating on the key role that Augusta Bay could play in exporting Hg to the Mediterranean Sea, as an effect of the outflow intercepted by the Levantine Intermediate Waters (LIWs). Also, data recently collected by ICRAM (2008), ENVIRON International Team (2008) and Ausili et al (2008), demonstrated HgT transfer from the abiotic system (sediments and seawater) to fishes (top predators and filter-feeders) and documented significant health risks associated with the consumption of fish caught in the area.…”

“…In the last decade, several studies have provided detailed information on the pollution levels and risks for human health of resident populations of Augusta Bay (ICRAM, 2005;Ausili et al, 2008;Di Leonardo et al, 2007, 2008ENVIRON International Team, 2008;Ficco et al, 2009;Sprovieri et al, 2011). Sprovieri et al (2011) reported high-resolution maps of HgT distribution from superficial sediments collected in 2005, highlighting extremely high concentrations (ranging between 0.1 and 527.3 mg kg À1 ) and speculating on the key role that Augusta Bay could play in exporting Hg to the Mediterranean Sea, as an effect of the outflow intercepted by the Levantine Intermediate Waters (LIWs).…”

Ecotoxicological Evaluation of Parallelomorphus laevigatus (Coleoptera, Carabidae) as a Useful Bioindicator of Soil Metal Pollution

“…The high values of numerous trace metals detected in beetles right from the control site are mainly due to the emissions sources of the nearby industrial plants; but also the intense agricultural activity in nearby areas certainly contributes, at least for cadmium, very abundant in both prey and predators [30]. Particularly alarming is the very high concentration of Hg in insect tissues from this site; on the other hand, a huge burden of this dangerous metal has already been found in this southern area of eastern Sicily in previous research on both sediments and animal tissues [31][32][33][34]. Indeed, various authors (e.g.…”