## 6 Mediterranean Coastal Communities as an Informative Case Study  
Certain Mediterranean communities may be more exposed to the negative effects of seafood contaminants, for both environmental and cultural reasons. The Mediterranean Sea is a semi-enclosed basin, surrounded by countries highly industrialized and with high agricultural development, and, as such, is of particular concern with respect to contamination by toxic compounds. The Mediterranean Sea is generally considered a geological hot spot for mercury [26], as it is characterized by large deposits of HgS that account for about 65% of the global mercury reserves [113]. Moreover, it should not be surprising that several studies have shown higher levels of contaminants in marine organisms from the Mediterranean Sea compared to those from other geographic areas [6; 47; 114; 115; 116], with levels of PAHs and especially Hg often exceeding recommended limits for human consumption [6; 30; 117; 118]  
Concerning Hg, in particular, the highest concentrations in Europe tend to be found in fish caught in the Mediterranean Sea [16]. Data showed a more marked Hg bioavailability in the Tyrrhenian and the Adriatic coastal waters compared to the rest of the Mediterranean [119], and MeHg levels higher than the legal limit have been discovered in seafood caught in both areas [117; 118; 120; 121; 122; 123; 124], as well as in the Ionian Sea (Sidimar 2018), and in different classes of marine organisms, including fishes, crustaceans, and mollusks. MeHg contamination hotspots are represented by the Trieste gulf [125], the coastal waters between Cattolica and Rimini, in the Central Adriatic Sea [124], and those between Anzio and Civitavecchia, in the Central Tyrrhenian Sea [126]. Turning to PAHs, potential contamination hotspots are generally deemed to be located near Taranto, Trieste [125], Naples [127; 128], Genoa and Palermo [127]. It is also worth reporting that some studies revealed possible risks to human health arising from the consumption of PAHs-contaminated seafood from the Mediterranean. The above conclusions were drawn from the calculation of risk indexes, such as the Excess Lifetime Cancer Risk (ELCR) and the Target Hazard Quotient (THQ) [30; 73; 129] The authors calculated the ELCR according to the following equation:  
ELCR = EF (day/y) \(\times\) ED (y) \(\times\) IR (Kg/day) \(\times\) CSF (mg Kg\({}^{-1}\) day) \(\div\) BW(Kg) \(\times\) AT  
where EF is the exposure frequency (365 days/year), ED is the exposure duration (y), IR is the ingestion rate, which is equal to PAH concentration times the mean ingestion rate of the species, CSF is the Cancer Slope Factor for each of the analyzed PAHs (OEHHA, 2009), BW is the body weight, and AT is the averaging time, which is equal to EF \(\times\) ED. A CR above the acceptable lifetime risk (ALR) of \(10^{-5}\)[130] indicates a probability greater than 1 in 100,000 of developing cancer [30]. THQ indicates the ratio between exposure and the reference dose, and is calculated through the formula:  
\[\text{THQ = EF (day/y) \times ED (y) \times IR (Kg/day) \times C (mg\text{ Kg }^{-1})\div\text{ RfD (mg kg }^{-1}\text{ day) \times BW(Kg) \times AT}}\]  
In Europe, coastal populations consume greater amounts of seafood compared to inland populations [11]. Moreover, Mediterranean coastal populations are characterized by food habits based on local seafood consumption [26], and European countries bordering the Mediterranean are among the world's highest seafood consumers, with Spain, Italy and France accounting for more than half of the European expenditure on fish and fishery products, despite having only around a third of the EU's population (EUROSTAT, 2014). In Italy, apparent consumption of fish and seafood products amounted to 28.4 kg per capita, a share significantly higher than the EU average (EUROFISH, 2015). The traditionally high consumption of local seafood can lead to high MeHg and PAHs exposure levels among Mediterranean communities. The above scenario is supported by several lines of evidence.