High concern chemicals in top layer sediments of the northern Adriatic seabed as markers of old waste dumpings

The results are presented of a survey planned to assess the presence of high concern chemicals in sediments collected in a northern sector of the Adriatic sea neighboring the Venice lagoon. For the assessment, persistent marker chemicals were selected from the families of polycyclic aromatic hydrocarbons, polychlorobiphenyls, polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and chlorinated pesticides. Based on the chemical-specific concentrations and PCDD + PCDF profiles determined in the sediments analyzed, dumping zones appear to have existed approximately 5–6 km away from lagoon shoreline. Contamination levels exceed the quality criteria established by the pertinent Italian national regulation at many sampling sites, eventually reflecting (“fingerprinting”) industrial activities once performed in the industrial settlement of Porto Marghera within the Venice lagoon. In coastal samples, concentration levels appear to be lower than those determined at offshore sampling sites.