## 2 Materials and Methods  
The literature search was carried out using Scopus and PubMed, aiming for the retrieval of publications reporting PAHs levels in seafood, i.e., in marine species included in D.M. 19105, 22 September 2017, Annex 1, which details commercially relevant fish species in Italy, or having \"commercial\", \"minor commercial\", \"subsistence fisheries\", or \"of potential interest\" in the \"Human uses\" section on FishBase ([[https://www.fishbase.se/search.php](https://www.fishbase.se/search.php)]([https://www.fishbase.se/search.php](https://www.fishbase.se/search.php)), accessed on 15 January 2022), or whose specimens were recovered from the fish market. Moreover, publications had to report PAH concentrations measured in marine species caught in the Adriatic (FAO geographical subareas 17 and 18), Ionian (FAO geographical subareas 13-16, 19-21) or Tyrrhenian Seas (FAO geographical subareas 8-10, 11.2, 12). From each publication, we extrapolated several data, including the sample location and date, species and biological tissue investigated, sample length (cm) and weight (g), sample size, and PAH concentrations detected (mg/kg) (Table S1 for the full list and description of variables included in the database). Moreover, the database comprises a column specifying whether the record comes from wild, farmed or transplanted animals. Each record was georeferenced, providing latitude and longitude in decimal degrees of the sampling location. Following [51], a geographic precision code was assigned to each record (Table S2), based on whether the study provided the exact coordinates or a more or less precise description of the sample location, from which geographical coordinates were inferred. The trophic level of each species was obtained from online resources (Table S3) and included in the database. Abbreviations for the biological tissue where PAHs concentration was measured, as well as for each PAH and molecular weight class (i.e., LMW, MMW or HMW PAHs), are reported in the Supplementary Materials (Tables S4-S6, respectively). A column specifying if the reported PAH concentration is expressed in fresh (FW), wet (WW) or dry weight (DW) was added to the database (Table S7). Moreover, whenever a study provided concentration in DW, we converted that measure in WW, reporting both the original and the inferred value in separate columns. In the analyses, FW measurements were considered WW. For statistical analyses, when the measured concentration was below the limit of quantification (LOQ) or limit of detection (LOD), and the authors specified those limits, we assigned to that record a value equal to half the LOQ or LOD. For conversion from DW to WW, we used the following formula:  
\[\text{C}\;(\text{mg}/\text{kg}\;\text{w.w.})=((100\;-\;\%\;\text{of}\;\text{ water})\div 100)\times\text{C}\;(\text{mg}/\text{kg}\;\text{d.w.}) \tag{1}\]  
where C is the PAH concentration, and % of water is the percentage of water in the analyzed tissue. The percentage of water in Mediterranean mussel (_Mytilus galloprocinicialis_) and Manila clam (_Ruditapes philipipinarum_) was assumed to be equal to 85%, based on personal data not shown. The percentage of water in common sole (_Solea solea_) liver, gills and muscle was assumed to be equal to 72.75%, 70% and 74.4%, respectively, based on [33]. Finally, the percentage of water in red mullet (_Mullus barbatus_) fillet was assumed to be equal to 80%, following [51]. Two health risk indexes (Table S8), excess lifetime cancer risk (ELCR) and target hazard quotient (THQ), were calculated for each record and included in the database.