Humans have been eating fish since the beginning of time. Fish and seafood are with no doubt an essential source of protein, vitamins, and omega-3 fats. Over half of our global population depends on this food source.

Including fish in our diet can reduce the risk of several health issues, such as diabetes, heart disease, inflammation, and cholesterol. But if we think again, we’ve been polluting the oceans with more than 1.4 billion tons of trash including industrial waste, sewage, radioactive waste, and agriculture chemicals, every year.

If the fish we eat comes from contaminated waters, it isn’t difficult to realize we are eating contaminated fish. 

Which Type of Toxins Are We Consuming While Eating Fish?

Polychlorinated Biphenyls

Known as PCBs, they are highly toxic industrial compounds carrying serious threats to fetuses, babies, and children’s health. The chemical properties of PCBs made them useful for a variety of industrial applications, including electrical transformers, carbonless paper, lubricants, and hydraulic fluids. Although they can no longer be produced in the US since 1977, PCBs are hard to disappear as they are slow to break down. In other words, PCBs persist in the environment. They accumulate in the sediments at the bottom of rivers, lakes, streams, and coastal areas. They are eventually absorbed in the fatty tissues of fish. People that eat these fish are presented with contamination levels that can lead to neurological and developmental problems.

The concentration of PCBs in fish will depend on the type of fish and the area where it was caught. In general, fish that feed in the bottom such as bluefish, sea trout, lake trout, bass, striped bass, American eel and walleye captured in contaminated waters, have higher levels of PCBs.


Mercury occurs naturally in our planet’s crust. However, anthropogenic activities such as fossil fuel combustion and mining significantly extended mercury pollution worldwide. Once mercury is released into our atmosphere, it will eventually settle in land and waters. When settled in the ocean, mercury converts into methylmercury through natural processes. This highly toxic substance builds up in fish, shellfish, and animals (including us) that eat those fish and shellfish.

Most people in the world have at least a small amount of methylmercury in their bodies, which shows that its presence in the environment is ample. By consuming it, we are compromising the health of our digestive, nervous and immune systems; skin, kidneys, and lungs. In the US alone, over 75,000 babies per year may have increased learning disabilities related to methylmercury exposure in their mother’s uterus.

Canned albacore tuna, tuna steaks, halibut, shark, sea bass, swordfish, tilefish, king mackerel, Spanish and Atlantic mackerel usually have high concentrations of methylmercury in their flesh.  


By now, we know quite well how plastic is affecting the environment, especially the ocean. When it comes to the fish we eat, plastic can find its way to our dinner table in the form of microplastics and microbeads.


Microplastics are tiny pieces of plastic that can have the size of a sesame seed. Imagine a plastic bottle traveling in the ocean. Over time and under the action of the sun and waves, the plastic bottle will break into pieces over and over again. These pieces become so small they reach the status of microplastic.

Plastic contains industrial chemicals that are toxic to us and the environment. One of these chemicals is the famous bisphenol A (BPA). About twenty years ago, researchers from the Washington State University found by accident that BPA was leaching out of plastic cages, contaminating the mice within. This lead to anomalies in mice fertility and eggs. After several studies, it was clear that BPA exposure has a negative effect on monkey, fish, and human reproduction. The tiniest animals from the base of the ocean’s food chain are eating microplastics and absorbing its chemicals into their bloodstream and tissues. Other fish will eat these small animals, even fish we like to eat. The result is the same as in other animals: we are letting all the plastic toxins enter our bodies.


Microbeads have some similarities with microplastics. However, microbeads come from a different source – our cosmetics, toothpaste, and exfoliants. Microbeads are made of plastic and are less than 1 millimeter in size. The difference from microplastics is they don’t break down over and over again from other plastic products. They are instead manufactured and included in our hygienic and beauty products – on purpose. 

US households release every day 808 trillion microbeads down the drain. As they are such small particles, around 8 trillion of them can pass through the waste treatment plant. This amount could cover 300 tennis courts.

Once microbeads enter the ocean, they accidentally make part of the food chain. They can easily trick other animals because they look like eggs. As a result, more than 250 marine species mistake them for food. Microbeads also attract toxic chemicals as they travel through the waters, so when an animal consumes them, they carry those toxins to the animal’s bloodstream. We are no different from these animals, so the same happens to us when we eat fish or seafood that ate microbeads.

Marine commercial species such as mussels, lobsters, oysters, crabs, mackerels, and anchovies eat plastic. And even people who don’t eat fish are not safe from plastic toxins.  They are also in the salt we use in our kitchens. 

eating fish

PCBs, mercury, and plastic have been the most famous intruders in our oceans. They are contaminating ecosystems, and consequently, the fish and seafood we put on our tables.  But they are not alone. Several other sources of contamination travel every day to the oceans: runoff from sewage systems, factories, nuclear testing areas, farms, and the list goes on.

According to UNESCO, over 80% of all waste entering our oceans comes from land. Our pollution is so extreme that it created more than 500 marine dead zones around the world. We are overloading our oceans with so many toxins to the point we are consuming them. And since most of the fish are not labeled properly with the area it was caught, we have absolutely no idea in what conditions these fish come from. 

The ocean should be a source of health to us all. Sadly, that’s not happening as the fishing industry doesn’t even tell us what happens in the process. As long as all types of human toxic waste continue to enter our oceans, we will be eating fish that most likely does more harm than good to us.