Implementation of digestion and characterization procedures for control standardization on samples of Gilthead Seabream (Sparus aurata) and plastic polymers from the coastal environment of the Asinara Gulf (Sardinia, Italy)

• A digestion procedure for on animal and plastic samples was implemented. • Plastic samples were characterised by μ-FTIR. • The use of KOH 10 % was the most effective in the digestion of animal tissues. • Trial C (40 °C for 48 h) guaranteed a lower impact on plastics. • Six different polymers were identified by μ-FTIR. The objective of the present study was the implementation of a digestion procedure along with Fourier transform infrared microscopy (μ-FTIR) analysis for control standardization on samples of Gilthead Seabream ( Sparus aurata ) and different types of plastic polymers isolated in the coastal environment of the Asinara Gulf (Sardinia, Italy). The study has been carried out across two steps, the first of which was necessary to evaluate the exact amount of potassium hydroxide (KOH) at 10 % to degrade the organic matrix of gastro-intestinal tract and muscle of Gilthead Seabrams samples as much as possible without causing alterations to the eventual polymers that may be present. Moreover, the possible effects of 10 % KOH at 60 °C for 48 and 72 h and at 40 °C for 48 h were evaluated through the examination of plastic polymers that can be easily ingested by aquatic organisms under the Stereomicroscope and Scanning Electron Microscope (SEM). The second step involved the characterization of these plastic polymers by μ-FTIR.The results showed that the use of 1/10 KOH 10 % proved to be the most effective for the digestion of animal tissues, but at the same time (40 °C for 48 h) able to guarantee a lower impact on plastics and greater time savings. The characterization of plastic polymers by μ-FTIR revealed that the samples isolated from the coastal environment of the Asinara Gulf (Sardinia, Italy) were mostly represented by polyethylene, nylon, polyethylene terephthalate, polystyrene, polypropylene and polyurethane. These plastic polymers can be easily ingested by aquatic organisms and humans are exposed to them via their consumption, but so far, the consequences and potential risks have not yet been quantified. The results of the present study represent a preliminary contribution to the control standardization on samples of Gilthead Seabream ( Sparus aurata ) and different types of plastic polymers isolated in Sardinian coastal environments.