Microplastics are widely present in our environment, these tiny particles have potential threat to human health due to their toxic effects. It is important to understand the ways of exposure to microplastics.
Oral intake is the primary method of exposure. Interestingly, people often experience multiple forms of exposure at the same time. A scientist named Rillig introduced the idea of the plastic cycle, meaning that microplastics can move between different parts of the environment. This plastic cycle increases the chance of human exposure to microplastics.
Let’s understand the pathways of human exposure to microplastics.
Pathways of Human Exposure to Microplastics:
There are different pathways through which microplastics enter into the human body.
1.Oral Intake
2. Skin Contact
3. Inhalation
Oral Intake:
Oral intake is the primary pathway of human exposure to microplastics. Microplastics come from various sources like plastic waste, aquaculture, agriculture, and different industrial activities. These microplastics enter the food chain, contaminating drinking water, seafood, salt, and even sugar.
It is estimated that each year, Europeans ingest 11,000 microplastics per person from shellfish alone. Overall, people consume 40,000 to 52,000 particles annually from various food sources.
In oceans, microplastics may be abundant, so seafood is a major contributor to exposure. For example, people who consume seafood like mollusks, crustaceans, and fish can be exposed to thousands of microplastics yearly.
In addition, microplastics are widely distributed in soil and agricultural systems.
Plants absorb these tiny particles and transport them into fruits, leaves, and stems, contaminating food and increasing the risk of human exposure.
Furthermore, some microplastics are suspended in the air, causing a constant exchange of pollutants between the atmosphere and the ground. As a result, continuous deposition of microplastics occurs on soil, crops, and water bodies, increasing the chances of human exposure.
Most food containers are made from plastics like polystyrene, polyethylene, and polypropylene. These food containers can also release microplastics. People who use these containers 4-7 times a week may consume 15-205 microplastic particles from them.
Silicone rubber baby bottles, when sterilized, also release microplastics, which are ingested by babies. In a year, a baby can ingest 660,000 microplastic particles through feeding bottles.
Skin Contact:
Generally, microplastics do not penetrate the skin directly. However, if we use personal care products containing microplastics, these tiny particles are deposited on the skin, and daily use of such products increases exposure risk. Face creams and cleansers often contain microplastics in the form of microbeads.
While larger particles might not easily enter the body through the skin, smaller nano-plastics can bypass skin barriers, causing local toxicity or exposure to harmful additives.
Particles smaller than 100 nm have the potential to pass the dermal barrier, while the dermal barrier inhibits the absorption of particles larger than 100 nm. The mobile phones we use can also release microplastics that are transferred to our hands.
When children crawl or play, they can also be exposed to these microplastics. When microplastics come into contact with the skin, harmful additives such as brominated flame retardants, triclosan, bisphenols, and phthalates are absorbed into the skin.
A study shows that flame retardants, which are substances added to plastics, can be absorbed through the skin. Polybrominated diphenyl ethers (PBDEs) specifically have toxic effects on human health, causing neurotoxicity, hepatotoxicity, endocrine disruption, and reproductive toxicity.
Inhalation:
Breathing is another way through which people can be exposed to nano-plastics or microplastics. The microparticles in the air are made of polystyrene, and polyethylene terephthalate and polyethylene with fiber sizes ranging from ten to eight thousand micrometers.
These tiny particles have been found in the air we breathe, both indoors and outdoors, with levels varying depending on location and environment.
There are various sources of airborne microplastics, such as waste dumps, farming, industrial clothing, and industrial pollution. Near coastal areas, sea breeze and sea spray also contribute to microplastic pollution.
When people breathe polluted air, they inhale microplastics, which can build up in the lungs, cross into the brain, and harm both respiratory and neurological health.
Each day, we breathe about 15 cubic meters of air and spend around 10 hours outdoors. A scientist named Vianello simulated the exposure of indoor airborne microplastics to human using a Breathing Thermal Manikin, which is an artificial human body form used for assessing indoor environment measurements.
Vianello found that all air samples were contaminated with microplastics, and their concentrations ranging from 1.7 to 16.2 particles per cubic meter. This shows that people can inhale microplastics indoors.
Related Post: What Are Microplastics & Why Are They Harmful?
Where Do Microplastics Come From?
Some Interesting Information:
- In the atmosphere, roads are the largest source of microplastics, contributing 84% of airborne particles.
- On average, people consume between 74,000 and 121,000 microplastics per year through breathing and eating.
- In Paris, outdoor air contains about 5.4 microplastic particles per cubic meter, while indoor air contains 0.9 microplastic particles per cubic meter.
- A scientist named Amato-Lourenço found microplastics in human lung. These particles are smaller than 5.5 micrometers and the size of fibers ranging from 8.13 to 16 micrometers.
- The main components of these microplastics present in the lungs are polyethylene and polypropylene.
- The size of microplastics present in the lungs is smaller than the tiny plastic particles in the air, meaning that humans can inhale these particles.
Finally:
In conclusion, microplastics can enter our bodies through various means, including what we eat, how we touch things, and even the air we breathe. As we become more aware of these pathways, it’s important to consider the potential effects on our health. By understanding how microplastics affect us, we can take steps to reduce our exposure and protect ourselves and our environment.
