1. What Microplastics Are and the Two Main Types
Microplastics are defined as pieces of plastic that are 5 millimeters (about 0.2 inches) or smaller in size [1]. Scientists divide them into two main types based on how they got to be so small.
The first type is called "primary microplastics." These are items that were manufactured to be small from the very beginning. The second type is "secondary microplastics." These start as larger pieces of plastic waste, like bottles or bags, which then break apart into tiny fragments due to the power of sunlight and waves [1].
2. Clothing and Other Sources of the Smallest Plastic Particles
When looking at primary microplastics that flow into the ocean, clothing is a huge contributor. A study by the International Union for Conservation of Nature (IUCN) in 2017 found that the biggest source was fiber dust released when washing clothes made of polyester and other synthetic materials. This accounted for about 35% of the total primary microplastics entering the sea [2].
The second largest source was particles worn off car tires as they roll along the road. This made up about 28% of the total [2]. When you add these two sources together, they account for more than 60% of all primary microplastics. This is separate from secondary microplastics, which come from breaking down trash like plastic bottles. It shows that invisible particles from everyday items are flowing into the ocean in massive amounts.
3. Plastic Microbeads in Cosmetics and Why They Were Banned
In the past, toothpaste and face washes often contained tiny plastic beads called "microbeads." These were added to scrub away dirt and dead skin cells. However, these beads were too small to be caught by sewage treatment plants. As a result, they washed straight down the drain and into the ocean.
To stop this, the United States passed the Microbead-Free Waters Act in December 2015. This law banned the manufacture of products with microbeads in 2017 and their sale in 2018 [3]. Around the same time, many other countries, including South Korea, the United Kingdom, France, Canada, and Taiwan, also moved to ban microbeads [3].
4. Research Finding Microplastics Inside the Human Body
Recent research has shown that microplastics are not just in the environment; they are also inside people. One study from the University of Hawaiʻi looked at placentas, the organ that provides nutrients to a baby during pregnancy. Researchers examined records from mothers who gave birth in different years.
They found microplastics in the placentas of 6 out of 10 mothers who gave birth in 2006. For mothers who gave birth in 2013, the number rose to 9 out of 10. In 2021, microplastics were found in all 10 placentas examined [4]. Not only were more people affected over time, but the actual number of plastic particles found in each person also increased year by year [4].
5. Whether Microplastics in the Body Cause Disease
Scientists are still trying to understand if microplastics in the body cause illness. A study published in 2024 examined plaque (fatty deposits) removed from the neck arteries of 257 patients during surgery. They found microplastics in the plaque of 58% of the patients [5].
The patients who had microplastics in their plaque had a higher risk of heart disease, stroke, or death over the next three years compared to those who did not have microplastics. Their risk was about 4.5 times higher [5]. However, this study only showed a link, not proof of cause. Other factors like lack of exercise or diet could also play a role. The researchers stated that more study is needed to understand the true connection [5].
6. Ways to Reduce Microplastics, Such as Catching Clothing Fibers
Since washing clothes is a major source of primary microplastics, one solution is to catch the fibers before they leave your home. Filters and nets designed to catch fiber dust can be attached to washing machines and are sold commercially.
Regarding cosmetics, microbeads are now banned in many countries. Tire manufacturers are also working on developing tires that wear down less. However, it is difficult to completely stop the shedding of fibers from clothes or the wear of tires. Instead, efforts continue to reduce the amount produced.
7. How to Investigate Microplastics at Home, Starting With Clothing Tags
You can start by looking at the tags on your clothes. This helps you see if they are made of synthetic fibers like polyester or natural fibers like cotton. Comparing these materials can help you understand where some of the dust comes from.
You can also help by picking up large plastic trash from nearby rivers or beaches. Preventing large items from entering the water stops them from breaking down into microplastics later. If you want to learn more, write down one question that interests you, such as "Which is more common: primary or secondary microplastics?" This can be a good starting point for further research.