Plastic contamination has emerged as a global environmental concern. Studies carried out between 2000-2019 have estimated there are trillion individual pieces of microplastic (MPs, size less than 5 mm) in the world’s oceans. Due to their small size, MPs can be ingested by many marine species, and bioaccumulated through the food chain to pose a feed and food hazard. However, the associated risks are still largely unclear as there is a lack of well-established analytical methods for identification, characterization, and quantification of MPs in food to support exposure studies for risk assessment.
In this study, we have developed and validated an analytical method that can be used to identify, size characterise and quantitate, by both number and mass, MPs that are present in seafood. Notedly, our method was able to simultaneously quantitate MPs by both number and mass, with mass being a more consistent measure for data interpretation. The analytical method was subsequently deployed for a survey of MPs in seafood sold in Singapore retail markets. Our survey results revealed that MPs were widely present in most types of seafood available in the Singapore market, e.g., mussels, clams, and fish in various shapes (pellets, fragments, or fibres in diverse polymers) and sizes (10 µm- 4000 µm), with polyethylene (PE) and polypropylene (PP) being the most abundant. While this study aimed to elucidate the presence and abundance of MPs contamination in different seafood sold in Singapore markets, our findings are largely in line with previous surveys carried out in other countries.
This study has not only revealed insights on the MPs that are present in seafood sold in Singapore retail market but also provided a model workflow that can be extended to other food types in future studies to generate data that can be used to inform the type, scale and extent of human dietary exposure to MPs from food.