Small pieces of plastic called microplastics can travel through wastewater into the ocean, where animals may consume them. Over time, this can cause microplastics to accumulate in animals who eventually become food for humans.
According to Plastic Oceans, more than 8 million tons of plastic end up in our oceans each year.
A 2020 study of microplastics in five different types of seafood found plastic in every sample the researchers tested, suggesting that microplastics do find their way into our food products. This may affect human health.
Keep reading to learn more about plastics in seafood, including the associated health risks and more about the dangers of ocean pollution.
Larger pieces of plastic present a number of health risks for sea life, as plants and animals can become entangled in them. However, in recent years, researchers have also turned their attention toward microplastics.
Microplastics are tiny pieces of plastic less than 5 millimeters long. Their small size means that they can travel easily throughout the ocean. Animals may mistake them for food or accidentally consume them when eating other food.
Larger pieces of plastic can become microplastics as they break down over time and move around the ocean.
Some manufacturers may also use microplastics in their products. For example, cosmetic companies first began using tiny pieces of plastic in beauty products about 5 decades ago.
These small pieces of plastic are common in some exfoliating products and toothpastes because they are a cheaper alternative to nonplastic ingredients.
Consumers can check their beauty products by looking for microbeads on the label, or by using the Beat the Microbead app. It is worth noting that the United States banned the use of microbeads in cosmetics and personal care products in 2015.
Microplastics are highly prevalent in seafood due to the vast quantity of them in the ocean.
Research consistently finds microplastics in a wide variety of animals, in both oceans and rivers that feed into the oceans. For example, one 2020 study of two fish species in a river found that 100% of these fish had microplastics in their bodies.
Plastics, and especially microplastics, can travel up the food chain. The closer to the top of the food chain an animal is, the more likely it is to eat lots of microplastics.
This occurs because smaller animals eat plastics, then larger animals eat those animals, and larger animals again eat those animals, all of which allow microplastic levels to continue accumulating.
Humans, at the top of the food chain, may then eat plastic-contaminated animals.
There is no way to eliminate microplastics from an animal once they are present, and there is no source of wild seafood that can guarantee that their products contain no microplastics at all.
Researchers do not yet fully know the effects of consuming plastic-contaminated seafood on human health. It may take decades to fully understand the effects of microplastics, since some might be cumulative, appearing only after several years.
It is also difficult to control studies into the effects of microplastics, since people may have microplastic exposure from other sources than seafood alone.
The Food and Drug Administration (FDA) have not yet developed a guideline or limit on the consumption of many sources of microplastics, so the amount of contamination in different types of seafood may vary.
Some potential effects of eating microplastic-contaminated seafood include:
- Oxidative stress: This is an imbalance between antioxidants and damaging free radicals in the body. This may have wide reaching implications for a person’s health, including increasing their risk of serious health issues, such as cancer and heart attack.
- Neurotoxic effects: Exposure to plastics may damage the neurons, increasing the risk of brain health issues such as dementia.
- Endocrine disruption: Plastic may be an endocrine disruptor, which means that it can change the way the endocrine system and the hormones it controls behave. This can affect fertility, behavior, and overall health.
- Thyroid damage: Exposure to microplastics may damage the thyroid. The thyroid regulates several important functions and plays a role in controlling hormones that affect fertility.
- Cancer: Exposure to plastics may also increase the risk of cancer. This may happen because of the direct effects of chronic plastic exposure or due to the other forms of damage that plastics can cause. For example, oxidative stress is a risk factor for cancer.
Farmed fish do not always contain microplastics, particularly when the farming environment is well-controlled. However, a number of studies have found microplastics in farmed seafood.
Plastic is a major cause of ocean pollution. This is due, in part, to its sturdiness as a material. More specifically, it does not easily break down, which means that large pieces of plastic can remain in the ocean for many years.
Half of the 300 million tons of plastic produced annually is for single use, which means that it will likely end up in a landfill and may eventually travel to the ocean. One 2015 article suggests that around 80% of ocean plastics come from the land, but the authors also say that this is unproven.
It is also vital to note that microplastics in seafood are just one small part of the reason that our oceans are so highly polluted.
In addition to contaminating seafood, plastic particles in the ocean can injure and kill marine life, in turn disrupting the ecosystems and food chains and leading to potential extinctions along the way.
People have found around 1 in 3 species of marine mammals stuck in plastic at some stage, and around 90% of seabirds have plastic particles in their stomachs.
Plastic is not the only form of pollution present in the oceans. Numerous other pollutants can harm animals, contaminate the food supply, and destroy ecosystems.
- fertilizer from water runoff
- oil from oil spills
- other toxic chemicals that companies or individuals dump into the ocean, that enter the ocean through accidents, or that travel to the ocean from water runoff
There is a great deal of work to be done to protect human health and to save these millions of species living in and feeding off our oceans.
Microplastics may be very harmful to human health. One of the major concerns among public health advocates is that researchers do not yet know the effects of these chemicals or whether there is a safe level for consumption.
Because even farmed seafood can sometimes contain microplastics, it may be impossible to eliminate this contaminant from the human diet while still eating seafood.
People who worry about microplastics in their food can discuss them with a doctor or dietitian, who may be able to make recommendations to either offset the risk or help replace seafood in the diet.