Microplastic contamination of the marine environment is widespread, but the extent to which the marine food web is contaminated is not yet known. The aims of this study were to go beyond visual identification techniques and develop and apply a simple seafood sample cleanup, extraction, and quantitative analysis method using pyrolysis gas chromatography mass spectrometry to improve the detection of plastic contamination.

This method allows the identification and quantification of polystyrene, polyethylene, polyvinyl chloride, polypropylene, and poly (methyl methacrylate) in the edible portion of five different seafood organisms: oysters, prawns, squid, crabs, and sardines.

Polyvinyl chloride was detected in all samples and polyethylene at the highest total concentration of between 0.04 and 2.4 mg g⁻¹ of tissue. Sardines contained the highest total plastic mass concentration (0.3 mg g⁻¹ tissue) and squid the lowest (0.04 mg g⁻¹ tissue).

Our findings show that the total concentration of plastics is highly variable among species and that microplastic concentration differs between organisms of the same species. The sources of microplastic exposure, such as packaging and handling with consequent transference and adherence to the tissues, are discussed. This method is a major development in the standardization of plastic quantification techniques used in seafood.