Microplastics: What Are They? And How Do They End Up In Our Ocean?

According to a 2017 UN report, there are more than 51 trillion microplastics in the sea – that's more than the number of stars in the Milky Way


9 Minutes Read

Microplastics in the ocean Is there really plastic in the fish you eat? - Media Credit: Adobe. Do not use without permission.

Looking for another reason to leave fish off your plate? Here’s a big one: There’s plastic in your fish. More specifically, microplastics.

According to a 2017 UN report, there are more than 51 trillion microplastics in the sea – that’s more than the number of stars in the Milky Way! Marine life such as shellfish and whales easily consume microplastics as they’re smaller than five millimeters.

What are microplastics? How are they harmful?

Microplastics are everywhere in the ocean. They can float at the surface, get mixed in with the water column, and even sink to the seafloor. They’re even in the Arctic and Antarctica. A recent study of microplastics in the deep sea found microplastic in every single filter feeder that was studied. Examples of filter feeders are clams, mussels, scallops, and oysters.

These microplastics can damage the gills of shellfish and block the digestive track of other marine organisms so that they slowly starve to death. It’s worth noting plastics are made from petroleum and natural gas, which aren’t sustainably sourced. Microplastics can also accumulate harmful pollutants over time such as Polychlorinated Biphenyls (PCBs) and pesticides that absorb into plastics. Not exactly something marine life should be ingesting. Worse yet, these are the same fish that end up in our plates.

Chemical leaching from microplastics also hurts important marine photosynthetic algae: They produce 10 percent of the oxygen that we need to live. Plastic pollution is able to interfere with the photosynthesis, growth, and oxygen production of Prochlorococcus, the ocean’s most abundant photosynthetic bacteria.

How do microplastics end up in our ocean?

Clearly, microplastics do more harm than good. So, how do microplastics end up in our ocean and into our fish? Unfortunately, there are many different sources for microplastic pollution. The top polluters are from fishing gear, clothing, tyres, plastic pellets, and cigarette butts. All of these shed microplastics and leach toxins over time.

Fishing gear

Microplastics: fishing gear
Fisherman will often discard broken nets into the ocean.

Fishing contributes to 20 percent of ocean plastic. We can thank discarded fishing gear for that. Every year, an estimated 640,000 800,000 tonnes of fishing gear is lost worldwide. This accounts for at least 10 percent of all plastic pollution. Fishermen will often discard broken nets into the ocean without impunity. Sadly, it’s more cost-efficient this way, opposed to properly disposing of them or recycling the nets. 

If you’ve ever seen the horrendous 700,000km squared Great Pacific Garbage Patch, 46 percent of the patch is made up of fishing nets. This is often referred to as ‘ghost gear’, which includes eel traps, baskets, and fishing ropes. This ghost gear is made from plastic, which breaks up into tiny microplastics over time and ends up in the digestive tracks of marine life.


Microfibres from clothes go from your washing machine straight to sewage plants or local waterways

Most clothes we wear today are made out of synthetic materials. Every time a piece of clothing is washed, it releases 1,900 plastic microfibres into the water. These microfibres go from your washing machine straight to sewage plants or local waterways. The fibers are too small to be filtered, so they end up washed out to sea. A 2011 study says our world’s oceans are filled with tiny microfibres that come from our clothing. The study involved traveling to 18 different shorelines –  85 percent of the sediment along the shores were composed of microfibres.

A recent study found this to be true. It also shows that fish are indeed eating plastic microfibers. The study looked into the main fish species targeted by Great Lake anglers: Brown trout, cisco and perch all had consumed plastic. Every one of the 18 species sampled showed some plastic and the majority of this was microfibres. Researchers traced these fibers back up the waste stream to local washing machines.

These plastic fibers do not biodegrade and when fish consume them, but instead build up inside their GI tracts causing them physical harm. The plastic then leaches contaminants into the fish and their environment. Microfibres can contain endocrine disruptors, neurotoxins and potential carcinogens. 


Microplastics: Tyres
Tyers are a blend of plastics, synthetic materials and chemicals

Tyres are actually the biggest source of plastic pollution in UK rivers and seas. It’s not that tyres are being tossed into rivers or oceans, but the microplastics they shed while the car is being driven. Tyres are actually a blend of plastics, synthetic materials and chemicals after all. As a tyre wears down, shreds of material peel off and end up littering the road, then washing into streams and rivers when it rains. Half a million tonnes of tyre-wear fragments are released every year across Europe. About 19,000 tonnes of microplastic tyre pollution ends up in our waterways and seas.

Plastic pellets

Microplastics: plastic pellets
Million of plastic pellets end up finding their way into freshwater sources and, eventually, the ocean

Plastic pellets, aka nurdles or ‘mermaid’s tears’, are tiny toxic pellets that are spliced down to make them easier to transport during the manufacturing process. Unfortunately, millions of these little pellets end up finding their way into freshwater sources, and eventually the ocean. The plastic industry releases an estimated 53 billion nurdles annually in the UK – that’s the same amount it would take to make 88 million plastic bottles. Nurdles’ tiny size and bright colors make it easy for marine life to mistake it for food. This is even worse because they harbor toxic chemicals from the organic pollutants that fester on their surface.


5.6 trillion cigarettes are manufactured each year

These are the largest single man-made contaminant of our oceans. This polluter outpaces the plastic bag and straw. 5.6 trillion cigarettes are manufactured each year. Up to two-thirds of them are estimated to be disposed of irresponsibly.

Specifically, it’s the filter that’s the culprit. It’s made of particularly resilient plastic, cellulose acetate, that can take up to 10 years to decompose.

How do microplastics affect humans?

Now that we understand where the microplastic is coming from, and the dangers they pose to our marine life, how does it affect us? For starters, we’re literally eating plastic. By consuming fish who’ve consumed plastic, we’re putting that into our own bodies.

The average person unwittingly consumes five grams of plastic each week throughout the course of daily life. That’s about the weight of a credit card. This amounts to about 250 grams per year, which is more than a half-pound of plastic every 12 months.??? While you may not be eating plastic directly (who would?), you can indirectly consume it from the fish you eat.

The long-term health effects of unwittingly ingesting this much plastic per week are still largely unknown. But it’s safe to say no amount of plastic in our digestive system is ever a good idea. It doesn’t belong there, and that’s not something that can be disputed.

At this point, we need more research into exactly how ingesting microplastics may affect human health. But it’s safe to say our oceans, and our health, will benefit greatly from a reduction of microplastics. It’s worth noting there are other sources of microplastic carriers: bottled water, tea bags, sea salt, beer and honey can contain and transfer microplastics to humans as well. 

How can we stop microplastic pollution?

stop eating fish
‘Our best bet on stopping microplastic pollution is to stop eating so much fish’

Our best bet on stopping microplastic pollution is to stop eating so much fish. If we cut fish from our diets, we’d be saving over 640,000 tonnes of fishing gear from entering our oceans every year, protecting biodiversity which helps combat climate change, and saving the life of sentient fishes.

When we cut back on fish, we can also help stop overfishing and bycatch. Overfishing is when the fishing industry catches fish faster than stocks can be replenished. Bycatch is when fish or other marine species are caught unintentionally while catching another target species. Both degrade ecosystems and create food insecurity for communities that depend on fish to survive. Sadly, two-thirds of the world’s seafood is overfished and global bycatch may amount to 40 percent of the world’s catch, totaling 63 billion pounds per year.

It’s safe to say cutting fish from your diet will help reduce microplastic pollution, and protect biodiversity. At the least, we need to advocate for more sustainable fishing practices to be put in place ASAP.

Other ways we can reduce microplastic pollution

  • Choosing natural fibers in clothing over synthetic fibers (which shed microfibres with each wash).
  • Washing clothes less often (a single load of laundry can release hundreds of plastic microfibres into the water supply).
  • Driving less and choosing to walk or bike more (if you must drive, drive gently so less microfibres shed off tyres).
  • Advocate for more sustainable fishing regulations, like making it mandatory for boats to register the number of nets they have onboard and returning with the same number of nets, or face fines.
  • Holding the plastic industry accountable for all the plastic nurdles they lose track of that end up in our waterways. 
  • Avoid cigarettes as their filters are plastic. Or, support companies like Greenbutt that create biodegradable filters.
  • Adopting a plastic-free lifestyle overall that reduces the amount of single-use disposable plastic you use daily.

What are some ways you will help reduce microplastic pollution? Have you already given up fish? What are some ways we can hold the fishing industry accountable?

*This piece was supported by the One Movement, a social enterprise on a mission to eliminate ocean plastic. Every $1 spent at One Movement removes 1-pound of ocean-bound plastic. Find out how their reusable bottle ‘the One Bottle‘ gives a new life to plastic – transforming ocean plastic into homes for those in need! Sign up here to learn more.

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