**1. Introduction**

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two chemicals included in the large group of the perfluorinated compounds (PFC) which have been widely produced for industrial purposes since 1950 [1]. They are characterized by a fully fluorinated hydrophobic chain and a hydrophilic head and these properties, in combination with their high chemical stability, make these compounds unique for their ability to repel both water and oils. They have been used in many applications, such as surface treatments for coatings, clothes, carpets, packaging products, cookware, food contact papers, and as additives in the fire-fighting foam. They are considered

emerging pollutants, since they have been detected in human tissues and wildlife with increasing trends [2–4] and seem to meet the criteria of persistence, biomagnification, and long-distance transport, to be included in the persistent organic pollutants (POPs) under the Stockholm convention. Liver is the target organ of toxicity of these chemicals. Toxicity of PFOS and PFOA includes developmental effects, interference with transport and metabolism of fatty acids, immune-suppression, and interference with thyroid hormones. PFOA shows the typical effects of the peroxisome proliferator-activated receptor alpha (PPARα) agonists, which include increase of β-oxidation and cytochrome P450 mediated reactions [5]. For both compounds, carcinogenicity has been shown in animal study mediated by a non-genotoxic mechanism.

PBDDs and PBDFs are another group of POPs formed as byproducts of other brominated compounds, such as brominated flame retardants (BFRs) or brominated biphenyls (PBBs), or ex novo in the combustion processes starting from brominated precursors. In addition, for PBDDs, a biogenic origin in the marine environment has been hypothesized [6]. These compounds are of concern because they seem to have the same mechanism of toxicity of the highly toxic 2,3,7,8-substituted congeners of the polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) through the binding to the aryl hydrocarbon receptor (AhR) [7,8], which is the protein mediating the dioxin-like toxicity [9]. Indeed, the classical fingerprint of the dioxin-like biological effects, such as wasting syndrome, thymic atrophy, chloracne, teratogenesis, reproductive effects, and immunotoxicity have been observed [10].

One of the main research gaps related to these pollutants is to what extent exposure for humans and other living organisms occurs [11], since few data on environmental occurrence are available, especially for PBDDs and PBDFs. Fish and fishery products are a known source of dietary intake of POPs for general population, since seas and oceans represent the final accumulation tank of such compounds and their tendency to bioaccumulate.

Within a more extensive research project on the welfare of wildlife and farmed fauna in the Mediterranean Sea [12], this paper reports detailed results species and location specific for PFOS, PFOA, PBBD and PBDF analysis in fish and other aquatic organisms collected in different areas of the Mediterranean Sea. The aims were to investigate the level of the contamination in farmed and wild fish at different trophic levels of the food chain and to assess human exposure associated to fish and fishery products consumption.

#### **2. Materials and Methods**
