Microplastics: A Hidden Threat to Marine Life and Food Safety

Plastic pollution is a big threat to our oceans and marine life. It’s constantly contaminating the water and harming animals on a large scale. Around 8 to 10 million metric tons of plastic are estimated to enter our oceans annually. These either break down into small pieces, known as microplastics or form massive garbage patches, posing a significant threat to marine ecosystems and food safety.

What are Microplastics?

According to the USA’s National Oceanic and Atmospheric Administration (NOAA), microplastics (MPs) are small plastic pieces that are less than 5 millimetres (about 0.2 inches) in length. MPs are composed of different varieties of polymers, which attribute various physical and chemical characteristics to them. MPs come in two types: primary and secondary (Andrady, 2011). Primary microplastics are made to be small and are used in things like face wash, toothpaste, and other personal care products. Secondary microplastics, however, are created when bigger plastics like bottles, bags, and other items break down into smaller pieces due to wear and tear, sunlight, and other environmental factors. These heterogeneous groups of plastics are raising ecological and food safety concerns all around the globe. 

Impact on marine life

The Intergovernmental Oceanographic Commission of UNESCO (IOC) estimates that there are approximately 50-75 trillion pieces of plastic and microplastics in our oceans. Because of their high prevalence and size, MPs are ingested by many marine organisms, from microscopic plankton to larger fish and shellfish. Mussels and oysters are especially at risk because they filter tiny particles from the water to eat, and accidentally take in microplastics too. Similarly, fish and crustaceans ingest these particles, mistaking them for food. 

When microplastics are eaten by small animals, they can be passed up the food chain to larger animals, and eventually even to humans who eat seafood. (GESAMP, 2016). Studies have shown that MPs can accumulate in the digestive systems of marine organisms, but there is also evidence suggesting they can move to other parts of the animal’s body, like the muscles or flesh, which are the parts that humans typically eat. In a study by Daniel et al. (2021), the researchers estimated that people who eat shellfish ingest around 13 microplastics particles per year. MPs ingestion can also cause several other adverse effects on marine organisms. Several laboratory studies reported that it can lead to tissue damage, reproductive problems, and behavioural changes. (Hantoro et al., 2019). These damages can create an imbalance in the marine ecosystem.

Impact on food safety

Research into the effects of MPs on food safety is still in its infancy, but initial findings are concerning. MPs are often concentrated in the gastrointestinal tracts of seafood, so those who eat whole fish or shellfish, like anchovies or mussels, are more likely to ingest MPs. Microplastics can also carry harmful chemicals that can contaminate seafood. These chemicals can come from the plastic itself or from contaminants, like persistent organic pollutants, pesticides, heavy metals and microorganisms, that the plastic has absorbed. When we eat seafood containing MPs, we may also be ingesting these toxic substances. (Teuten et al., 2009). Microplastics (MPs) can cause a range of harmful health effects in humans, including oxidative stress, cell damage and death, weakened immune systems, nervous system damage, metabolic problems, and the movement of MPs to other parts of the body. 

To conclude, the presence of microplastics in seafood is a major concern that affects the environment, as well as the safety of the food we eat. While much remains to be understood about the full impact of MPs on human health, the evidence so far underscores the need for continued research, improved regulatory measures, and proactive efforts to reduce plastic pollution. Ensuring the safety of our seafood is not only crucial for protecting public health but also for maintaining the integrity of our marine ecosystems for future generations.

Reference

1. Andrady, A. L. (2011). Microplastics in the marine environment. Marine pollution bulletin, 62(8), 1596-1605.
2. Daniel, D. B., Ashraf, P. M., Thomas, S. N., & Thomson, K. T. (2021). Microplastics in the edible tissues of shellfish are sold for human consumption. Chemosphere, 264, 128554.
3. GESAMP Sources, Fate and Effects of Microplastics in the Marine Environment: A Global Assessment; Kershaw, P.J. (Ed.) IMO. Rep.Stud.; GESAMP: London, UK, 2015; p. 96
4. Hantoro, I., Löhr, A. J., Van Belleghem, F. G., Widianarko, B., & Ragas, A. M. (2019). Microplastics in coastal areas and seafood: implications for food safety. Food Additives & Contaminants: Part A, 36(5), 674-711. 
5. Teuten, E. L., Saquing, J. M., Knappe, D. R., Barlaz, M. A., Jonsson, S., Björn, A., … & Takada, H. (2009). Transport and release of chemicals from plastics to the environment and to wildlife. Philosophical transactions of the royal society B: biological sciences, 364(1526), 2027-2045.