Microplastics and their associated organic pollutants from the coastal waters of the central Adriatic Sea (Italy): Investigation of adipogenic effects in vitro

Even though microplastic (MP) pollution in aquatic environment is nowadays widely studied, a huge gapof knowledge exists on their actual biological effects. In this study wefirst reported environmentalbaseline data on the occurrence and characterization offloating MPs in Italian coastal waters of theCentral Adriatic Sea by using a standardized monitoring protocol. Further, we analyzed the concentra-tions of MP-associated chemicals and evaluated their potential adipogenic effects using 3T3-L1 pre-adipocytes. MPs were found in each sampling stations showing the highest abundance (1.88±1.78items/m3) in the sites more distant from the coast with fragments as the most common shape category.All targeted organic pollutants (i.e.polychlorinated biphenyls - PCBs, polycyclic aromatic hydrocarbons-PAHs, organophosphorus - OP, and organochlorine - OC pesticides) have been detected on the surface ofthe collected MPs. The highest concentrations of PAHs were found on MPs from inshore (i.e.<1.5 NM)surface waters with low-ring PAHs as dominant components. Similarly, MPs from inshore waters hadhigherSPCB concentrations (64.72 ng/g plastic) than those found in offshore (i.e.>6 NM) waters(10.37 ng/g plastic). Among pesticides, all measured OPs were detected in each sample analyzed withpirimiphos-methyl as the most representative compound. For OCs, the sum of all concentrations ofcongeners was higher in coastal with respect to offshore waters. Moreover,in vitro3T3-L1 screening ofMP extracts indicated potential metabolic effects resulting in both adipogenesis and lipid uptake/storage