Microplastics Have Been Found in Human Body: Are they Harmful?

On September 22, 2021, a paper entitled "Occurrence of Polyethylene Terephthalate and Polycarbonate Microplastics in Infant and Adult Feces" published in the Environmental Science & Technology Letters found that there are many microplastics in children's feces.

More worryingly, in further research, scientists have found that microplastics can cause cell death, inflammation and affect metabolic activities in the body. Microplastics can pass through the body's digestive system and enter the blood system, causing systemic effects. Just like PM2.5, it can penetrate into the blood and affect human physiological functions.

Sources of Microplastics in Baby Faeces

Microplastics are plastic fragments and particles less than 5 millimeters in diameter. Specifically, microplastics range in size from a few microns to a few millimeters, and are mixtures of heterogeneous plastic particles in a variety of shapes. Although plastic is a relatively stable substance, it may have adverse effects such as blocking the circulation of body fluids.

The researchers extracted the feces of several children to study the composition of the material. The results showed that a high proportion of polyethylene terephthalate (PET) plastic was found in the feces of infants. PET is used in the manufacture of utensils in the food industry because of its stable nature, and many baby products contained this kind of plastic.

In the process of manufacturing plastic products, plastic particles are first melted, and then pressed with molds to form the desired shape. During this process, some small plastic particles may stick to the appliance and fall off when plastic products are slowly aging in daily use.

Further research shows that the composition of plastic particles in adults' feces is mainly PET, but surprisingly, the number of plastic particles in children's feces is 10 times that of adults!

Source: https://pubs.acs.org/doi/full/10.1021/acs.estlett.1c00559

There are a lot of plastic products for children, including pacifiers, toys, bedding, simple tools, etc. Therefore, children are exposed to too many plastic products. Moreover, because of brain development, infants and young children are interested in colorful toys at an early age and often put them in their mouths. Adults, in contrast, are much better in this regard. They use less plastic products, don't put them in their mouths, and pay more attention to hygiene.

Source: parenting.firstcry.com

This is not the first study on the presence of microplastics in infant products:

On October 19, 2020, a paper entitled "Microplastic Release from the Degradation of Polypropylene Feeding Bottles During Infant Formula Preparation" published in the Nature-Food found that when milk powder is prepared, polypropylene milk bottles will release up to 16.2 million microplastics per liter. At the same time, the level of water temperature also directly affects the amount of microplastics released.


Fortunately, the impact of this situation in Asia is relatively small, and researchers speculate that it is related to breastfeeding. Europe, America and Australia are the hardest hit areas affected by microplastics. But no matter where they are, modern children are still exposed to a lot of plastic products.

What Is the Cause of Microplastics?

The reason for using plastics to make various products is that the nature of plastics are stable, they are convenient for industrial processing, and the price is also quite low. However, because of its stable nature, it will not be digested in the human body. Because the microplastics are very small, some tiny particles can enter the circulatory system through capillaries in the intestines and stomach.

As early as October 23, 2018, the Medizinische Universität Wien and the Environment Agency Austria carried out a survey. They randomly checked the feces of 8 men, and there was no exception to the existence of microplastics. A study in March 2021 showed that more than 50 new environmental chemicals were found in the human body.

The micro particles of these chemicals may enter the human body's circulatory system, which is very important. With the help of circulatory system, the human body gets oxygen from the lungs and discharges carbon dioxide, absorbs nutrients from the intestines and stomach, and then transports them to all tissues via the blood vessel network. 

Foreign bodies entering the blood will first cause inflammation and other problems. The deposition of microplastics may affect blood circulation, so the path of immune cells may also be blocked, thereby affecting the immune system. Meanwhile, it may have adverse effects on metabolism, reproduction and nervous system health.


According to the above research, there are more microplastics in infants' feces, indicating that they may be exposed to more microplastics, and the excretion process of microplastics in the human body is not very clear now, which may also be a lifelong thing. Like silicon dust, they are also difficult to be decomposed by the human body. After entering the lungs, they will accumulate and enter the blood. Once the deposition in the lungs is too large, it will seriously affect human health.

The impact of microplastics is not limited to humans. Microplastics have also been found in marine animals. The reason is that plastic waste is all over the world, and has even sunk into the Mariana Trench.

Just as heavy metals accumulate higher up the food chain, microplastics may also enter human bodies from animals and plants in a similar way. What's more, microplastics have been found in the ice layer of Antarctica.

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