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How Did Microplastics Get Into Human Placentas?

How Did Microplastics Get Into Human Placentas?


By Marie Hasty, RN BSN

Have you ever seen a photo of a marine animal opened up with a stomach full of plastic? It’s a sad but common sight. Plastic production and distribution have climbed in the last several decades. So much so that microplastics have now made their way into human placentas.

In 2019, a study of dolphins, whales, and seals off the UK coast found that 100% of the dead animals had eaten plastics. Still, we haven’t heard much about plastics found in humans up until now. 

In a disturbing new study, scientists found microplastics in human placentas. This Italian study found microplastics in 4 out of 6 placentas. These results have startling implications, both for us and the world we live in.



A Growing Problem

Let’s start with how plastics get into our environment in the first place. Global plastic production is reaching 320 million tons annually. More than 40% is single-use packaging, which becomes garbage almost immediately.

Once thrown away, this plastic goes through environmental processes that break it down. Waves, abrasions, and ultraviolet radiation work together with bacteria to degrade plastic. Once it’s broken down it becomes something even more insidious: Marine Pollution that end up as Microplastics.



Where Do Microplastics Come From?

Microplastics can come from the degradation of larger pieces. They’re also produced in their small form. Unfortunately, environmental regulations are lax on plastic dumping. Industrial plants, sewage treatment facilities, and landfills dump large amounts of microplastics. They’re also present in everyday products, like some soaps, toothpaste, and cleaning products.



Microplastics in Marine Areas

Microplastics in marine areas come from several sources. These include fragmenting of larger plastics, and pellets spilled during fabrication and transportation. Sewage treatment facilities dump microbeads in the form of wastewater. It’s estimated that most of the seabed is actually plastic that comes from waste on land. It’s likely that their small size is what allows microplastics to get ingested by marine life (and us).



Sewage Treatment Plants

Sewage treatment is a big source of microplastics. Untreated sewage contains fibers from clothing, microbeads from soaps, and other personal products. 80-90% of these microplastics get retained in sludge and dumped as fertilizer on agricultural lands. Here, they remain in the soil where our food is grown. These fibers can remain in agricultural fields for up to 15 years after dumping stops.




Landfills contribute to microplastic waste. Improper waste handling, soil contamination, and aerosol creation all contribute to dumping. This last one is especially scary since air particles can move great distances.




Runoff from roads and transportation also leech particulates into the soil. One study in Australia measured topsoils near roads and industrial activities. In these areas, up to 7% of soil is actually microplastics by weight. Some experts argue that it’s more like 60%.

Because of these and other harmful sources of microplastics, it’s no wonder they’re so pervasive in our environment. This human waste is a lasting and harmful influence on the world we live in and will pass on to future generations. 

Unfortunately, there aren’t any ways of monitoring and reporting environmental microplastics. Each of the current methods has its own limitations. These include filtering, separating, degradation, and visual selection. There are far more microplastics in our environment than we can measure.



How Did Microplastics Get Into Human Placentas?

Humans ingest microplastics through breathing in aerosols as well as accidental consumption. Microplastics are in our food, especially in seafood, sea salt, and drinking water. They’ve even been found in commercial honey, table sugar, and beer. 

Once they’re inside living tissues they wreak havoc on natural processes. The host tissue recognizes a foreign body, creating an immune reaction. This causes inflammation in the body, as well as metabolic stress. They can also act as a vector for other chemicals and additives, causing more harm.

As the site of fetal nourishment, the placenta is vital for growth and development. Through the placenta, the fetus receives nutrients and oxygen. It’s also the site of differentiation, separating the mother’s immune system from the fetus’. 

A Working Theory

It’s thought that microplastics can get into human placentas through the same mechanisms our bodies use to transport nutrients. Because they’re so small, microplastics get carried through cells along with nutrients. Once microplastics have reached the maternal side of the placenta they can invade the tissue even further. 

This delicate natural system is how our species continues itself. We’re not sure what the presence of manmade waste in this environment will do to humans.

One hypothesis is that microplastics may accumulate and create local toxicity. This triggers the host’s immune response into action. Natural defenses are reduced, and immune responses against other pathogens might weaken. Inflammatory immune responses from microplastics can lead to other ills over time. 

In other species, exposure to microplastics causes changes to gut microbiota. Over time this can lead to immune disorders and other complications.

Also disturbing is the fact that we’re still not sure how prevalent microplastics or marine pollution are in this environment. This study used only a small part of the placenta. It’s reasonable to assume that microplastics exist in higher quantities than what was measured here.



What Does This Mean For Humans?

The scary thing is that we’re not sure. It’s impossible to experiment with microplastics and humans. But the effects of microplastics in animals are discouraging. These include hormonal problems since plastics almost universally contain estrogen. 

In laboratory animals, this estrogen exposure is linked to demasculinizing and other imbalances. Endocrine disruptions like this have huge health implications  affecting all species, including ours.

Scientists also worry about microplastic’s ability to pass the cellular membrane, which allows them to behave like natural molecules. This can result in Inflammation, changes in cell membranes, and other imbalances.

Microplastics in soil have the potential to alter water cycles and ecosystem functions. Plants need soil biodiversity on the microscopic level to grow. If 60% of the soil is plastic, that can’t happen.

Scientists are still investigating the effects of the widespread plastic particulates. One thing is for sure: the presence of microplastics in living organisms is a serious cause for concern.



How to Stop Ocean Pollution?

There are so many ways to reduce your plastic footprint!

Once plastic makes its way into our oceans, removing it becomes an uphill battle. But you can keep plastic from getting into the environment in the first place. Stay away from single-use plastics, like sandwich baggies and single-serving snacks. Buy food in bulk if you can, and invest in reusable containers. Stay away from single-use water bottles by picking up one of our Reusable Water Bottles from our Ocean Shop

Become an Ocean Blue Wavemaker! Now, every dollar donated helps us remove 5 pounds of plastic from the ocean!

Become a member of Ocean Blue Project! With every membership donation, we remove 250 pounds of plastic from the environment. Because of our members, we’re one step closer to our goals. We aim to plant 1 million trees and remove 1 million pounds of plastic marine debris from our coasts and rivers by 2025!

Let your kids immerse themselves in ocean education with our OBP Blue Schools Program! We’ve crafted a brand-new curriculum for you and your children. Coming this fall, Blue Schools will include home and classroom learning. Also, your young ones will experience first-hand the outdoor fieldwork plus exciting projects in their local community.

Want to keep learning about exciting environmental news? Keep up with the latest stories by following our Ocean Blue Blog!

Author Bio: Marie Hasty is a COVID ICU Nurse, writer, painter, and planet advocate.