Qualitative and Quantitative Screening of Organic Pollutants Associated on Microplastics from Ofanto River (South Italy)

There is considerable complexity involved to understand the impact of microplastics on the natural world due to their heterogeneous physic-chemical properties that make these synthetic polymers a multifaceted stressor. Although data on microplastics exposure levels in marine environments and organisms have rapidly increased in recent decades, limited information is available on chemicals associated with microplastics. Based on the first findings and the concerns of the scientific community herein we report results related to the identification and quantification of persistent organic pollutants adsorbed on microplastics collected from an Italian river (Ofanto) during different campaigns. Some of these compounds are added during plastics manufacture, while others adsorbed from the surrounding ambient. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) have been selected as target compounds to be quantified while a qualitative general non target-screening of plastic additives has been carried out by high resolution gas chromatography mass spectroscopy. Matrix blanks, (virgin polymers), were analyzed together with field samples in order to compare the concentration of adsorbed environmental contaminants to the amount of natural chemicals originating from plastics. The quantitative analysis of pollutants, underlined the presence of these contaminants on almost all samples. PAHs were found in all samples. The major pesticide quantified, associated with the plastic debris, was been DDE that showed values above the Italian regulatory limit set for soils. PCB 52 and five of the 16 EPA-PAHs were observed in virgin pre-production pellets suggesting a probable contamination or a use of these pollutants as plastic additives. Non-target screening of compounds associated to microplastics provided an overview of more than 90 organic chemicals identified, including hydrocarbons, ultraviolet stabilizers, antioxidants, plasticizers', lubricants and intermediates. This work is the first study that shows a detailed overview of the variety of chemicals associated on microplastics collected from an Italian river context.