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.