Plastic pollution is a global environmental problem. Whereas most of us are conscious of plastic bags and other single-use plastics, microplastics pose a less obvious form of plastic pollution. However, microplastics are everywhere, in our drinking water, air, and the food we consume. In 2020, researchers predicted that by 2040 there would be more than 600 million tons of microplastic waste in our oceans10.
Microplastics are just as dangerous, if not more so than regular plastic waste, presenting many toxic effects on living organisms and the environment.
The interaction of microplastics with the soil interrupts its functions, destroys its health, and kills the living organisms inhabiting the earth. It is also the cause of the extinction of some marine organisms. And we’re far from immune from the scourge of these tiny plastic particles, as studies have shown microplastics to damage human health by destroying human cells.
What are microplastics?
Microplastics are tiny plastic particles less than 5mm long. They come from all types of plastics - an aftermath of plastic use. Microplastics comprise high polymer materials and solid particles that are not degradable. These particles typically result from larger plastics breaking down into smaller particles.
Microplastics often also contain toxic chemicals used as additives. Three primary types of microplastics are in the ocean; polyethylene, polypropylene, and polystyrene.
Classifications of microplastics
There are two classifications of microplastics. They are:
1. Primary microplastics
Primary microplastics, also called nurdles, are tiny plastic fragments used for manufacturing some of the products we use in our daily lives. Primary microplastics are already tiny particles present in cosmetic products, textiles, and other products. Some materials that make up primary microplastics are polyethylene, nylon, and polypropylene.
Microbeads are a perfect example of primary microplastics in products like exfoliating cosmetics and personal care products.
In 2015, the United States and several other countries banned microbeads11. The microbead free water act of 2015 issued a ban that helped spread awareness of the danger of microplastics washing down our drains and ending up entering our environment and food chains.
Although the act reduced the number of manufactured microbeads produced daily, it didn't lessen the existing environmental plastic pollution. They take years to degrade like normal plastics.
2. Secondary microplastics
Secondary plastics are tiny plastic particles resulting from larger plastic materials degrading into small pieces. Over time, large plastic materials break apart into little particles that are not more than 5mm.
Scientific reports show that fragmentation is a common factor of secondary microplastics. Large plastic products disintegrate into smaller pieces due to physical, biological, and chemphotodegration in a process referred to as fragmentation. Also, exposure to sunlight breaks plastics into small fragments.
Studies show that microplastics can reduce to a size smaller than the eyes can see. So far, the smallest microplastic size found is 1.6 micrometers.
Nanoplastics are a type of microplastics that are less than 1nm. Nanoplastics is a term often used interchangeably for microplastics. However, they're distinguishable because nanoparticles have unique biological and physico-chemical properties.
Nanoplastics result from the manufacturing and degradation of plastic products. Additionally, they integrate naturally with natural elements and all forms of ions. They also bind with soil microbes and colloidal organic components (where small particles are suspended in another). Nanoplastics form through a process known as hetero-aggregation, the aggregation that happens in a unification of dissimilar colloidal plastic particles.
Nanoplastics are prevalent in marine environments. However, there aren't enough scientific reports about nano plastics, but there's the probability that they interact well with microorganisms as microorganisms sometimes live on plastic surfaces.
So far, no evaluation of the presence of nano plastics in food has occurred. One of the reasons why researchers have found the impact of nano plastics challenging to estimate is because of their reactive properties; they disintegrate efficiently, leading to the loss of samples.
Sources of microplastics
Microplastics travel over long distances. There are up to 7 primary sources of microplastics:
1. Synthetic textiles
The washing of synthetic materials creates microplastics through the wearing away of fibers. Synthetic fibers have high polymer, nylon, acrylic, and polyolefin contents. These separated small fragments of plastic polymers constitute a type of primary microplastic.
While doing the laundry in your home or at the dry cleaners, these fibers wash down the drain and through the sewage systems, potentially ending in the marine environment.
Researchers have found that just one clothes wash can release as many as 700000 microplastic fibers2. We can find microplastics resulting from synthetic fibers in up to 80% of the water waste across the world.
Laboratory studies examined 916 ocean water samples from 617 locations9, and the result was that 99.7% contained plastic fiber content. The quantity of the water was 13.447 liters, and scientists filtered out 23,593 fibers. The majority of these fibers were less than 1mm.
2. Road markings
Road markings are materials used on a road surface and asphalt to show information like pedestrian crossings, lane markings, and designated parking spaces. The types of road markings include:
- Preformed polymer tape
Paint is the dominant road marking that is used around the world, followed by thermoplastics. Plastic particles break off from thermoplastics and form polymer tapes due to corrosion by vehicles causing wear. Weathering also slowly turns them into smaller fragments. These fragments move through rainfall and air, finding their way into waterways, resulting in marine microplastic pollution.
Styrene-Butadiene Rubber refers to the grid of synthetic fibers from the corrosion of vehicles' tires. You can also refer to it as tire dust. This dust, caused as our tires wear through regular road use, is spread around the environment through the air and rainfall, finding its way into our everyday items.
Although there isn't accurate information on the transfer of microplastics from tires into the ocean, Norwegian and Swedish researchers found that a significant quantity of particles found in seawater originates from car tires.
4. Personal care products
Plastic microbeads are a primary material for manufacturing some personal care and cosmetic products. You can find plastic microbeads in exfoliating and cleansing products like body washes, toothpaste, and facial scrubs.
An extensive fraction of personal care and cosmetic products have high concentrations of plastic materials. Manufacturers also pack them in plastic packages, effectively increasing the plastic waste released into the environment.
5. Plastic pellets
Plastic pellets are an industrial raw material used in all forms of plastic production. Manufacturers melt them down and mold them into any desired shape.
Plastic pellets are a significant contributor to microplastic pollution. They enter our environment during manufacturing, processing, transportation, and recycling activities. In Europe, about 167,000 pellets get swept into the marine environment yearly3.
6. City dust
City dust refers to the fragments formed from the corrosion of objects, infrastructures, and blasting abrasives. Erosion of items occurs with synthetic soles and cooking utensils, while the decomposition of infrastructures refers to household and city dust, building coatings, and artificial turfs.
7. Marine Coatings
Marine coatings are similar to road markings. They're used to cover marine vehicles for protection. They use polyurethane, epoxy coatings, vinyl, and lacquers as coating materials for ships’ surfaces.
Microplastic pollution from marine coatings occurs during the building, maintenance, and use processes. Pre-treatment, coating, and equipment cleaning play a significant role in the fragmentation of these materials into microplastics.
How do microplastics affect the environment?
Microplastic concentrations are everywhere in the environment, affecting both the aquatic and terrestrial environments. Firstly, we will address how high concentrations of microplastics affect our marine environment.
Studies have found microplastics are in the air, soil ecosystem, freshwater, tap water, and oceans. A recent study even found microplastic concentrations in sea ice in the Arctic Ocean5.
We are also inhaling the microplastics present in the atmosphere as we breathe. They interact with inorganic pollutants and persistent organic pollutants like7:
- polychlorinated biphenyls (PCBs),
- dioxins, dichlorodiphenyltrichloroethane (DDT),
- polycyclic aromatic hydrocarbons (PAHs).
The interactions of microplastics with these elements allow them to be a carrier for toxins in the ecosystem.
Microplastics in the ocean are dangerous for marine life because they integrate with the marine food web and other organic contaminants. Marine organisms inhale and ingest ocean-born microplastics throughout their food chain, as aquatic life can’t distinguish them as foreign or inedible. The consumption of plastic causes a reduction in appetite, and it leads to lowered energy levels.
Marine organisms also suffer from behavioral problems, neurotoxicity, and a slow growth rate as microplastics enter their internal organs, bloodstream, and living cells. Marine biologists found a high percentage of crustaceans have microplastics in their digestive and respiratory tracts, as they mistake them for food.
Another way plastic production affects the environment is by causing damage to soil particles and land-based ecosystems. Microplastics have been found across all terrestrial ecosystems: agricultural lands and industrial and urban areas.
Microplastics have also been found in remote mountains, a long distance away from the manufacturing and consumption of plastics. They contaminate soil ecosystems when we dump plastic materials. Other ways microplastics contaminate the earth include:
- The use of plastic agricultural tools
- Water treatment plants
- Tire corrosion from vehicles
When microplastics enter the soil, their plastic particles change their structure and texture, resulting in a toxic effect on different groups of soil fauna like earthworms, snails, and nematodes. It also disrupts the symbiotic microbiota in the soil fauna gut and disturbs the movement of soil microarthropods by blocking soil pores1.
Chlorinated plastics contain 67% of chlorine that enters the soil ecosystem. Then, it is transferred all around the ecosystem, joining different water sources.
Animals that drink from chlorinated plastic-contaminated water experience a decline in their health functions. The additives used in plastic production affect animals’ hormone systems, can restructure the gene cells, and cause biochemical reactions in living organisms.
Effects of microplastics on humans
Microplastic concentration in the environment is dangerous to human health because we interact with everything in our environment.
We ingest microplastics through eating, drinking, and inhaling. Terrestrial and marine pollution of the environment affects the food chain.
Researchers are yet to attain quantitative knowledge about the toxic effects of plastic waste on our bodies, and further research is required to understand long-term impacts.
Humans use large quantities of plastics daily. We buy food-packed plastic bags, food containers, and other plastic consumer products. Tiny fragments from these plastic products integrate into the environment, consequently integrating themselves into the food chain. Although, scientists think the cooking process for some of the food we eat lessens the impact of consuming plastic waste.
Microplastics on our plates
Because microplastic ingestion starts with marine animals, they are the first in the food chain to exhibit chemicals and organic pollutants on their surface area. Humans consume a lot of aquatic organisms, and marine animals like fish are an essential source of proteins for humans. Statistics show consumption of 6.3 million pounds of seafood in the US in 201912. Many of these organisms have low concentrations of microplastics in their gastrointestinal tract.
Exposing living human cells to plastics might cause DNA damage, inflammation, oxidative stress, and other reactions. Oxidative stress often leads to inflammation, and a chronic inflammation situation can lead to other forms of health problems.
Furthermore, scientists suspect that plastics in the immune system lead to autoimmune rheumatic illness and systemic lupus erythematosus. Aside from more acute conditions, microplastics may affect how well our immune system functions.
Animals show that microplastics also interact with their metabolism, restructuring metabolic enzymes in the body, which leads to a reduction in energy levels. Given that humans have higher metabolism rates and energy levels, the impact on our metabolism cycles is likely lesser and more work still needs to be done to understand how microplastics affect human health13.
Researchers developed a means of detecting microplastics in human blood to understand their effects, assessing the level of polymer concentration in the blood of 22 people. Results showed four types of polymer concentration in the blood8.
Also, they found that humans pass out microplastics in the intestine through excretion. However, no conclusion has been drawn as to the health impacts of microplastics in our blood as it requires a more extensive study.
How to reduce microplastics in the environment?
Reducing the production of plastics is a significant means of reducing microplastics in the environment. Fewer plastic materials in our surroundings result in a reduction in microplastic pollution. Here are steps that help reduce microplastics in the ecosystem:
Reduce the production of plastics
Using less plastic is essential in reducing all forms of pollution, including CO2 emissions from production impacting climate change and using non-renewable fossil fuels as raw materials.
Unfortunately, only around 9% of plastic produced is recycled in the US, and the remainder of our discarded plastic waste is in landfills or burnt.
Disposable plastic products, known as single-use products, are the primary cause of the pollution we are experiencing, so we should reduce the rate we manufacture them.
Indulge in alternative reusable products like glass, ceramic, and stainless steel by-products. Choose a plastic product you can recycle when there are no organic alternatives.
Recycle already used plastic items
Because the global rate of plastic recycling is still a low 18%4, it's still a way of curbing pollution. Since it takes a long time for plastic to decompose, it is better to reuse plastic products multiple times. Some plastic bags and containers are reusable. Use them to package other things.
Also, instead of dumping plastic into the trash, you should gather them up and send them to recycling plants. You are saving the earth and protecting your health by indulging in a plastic-free lifestyle.
Use organic tea bags.
A video regarding the production of tea bags went viral in 2017. In the video, we learned that most companies produce tea bags that contain at least 25% of plastic polymer. Canadian researchers discovered that adding hot water to a tea bag led to the formation of about 11 billion pieces of microplastics6.
A cup of tea typically has 16 micrograms of microplastics. Whereas tea is generally known for its benefits to human health, plastic tea bags, which also don’t decompose, cause harm to the human body. To avoid the intake of microplastics, buy tea bags made with organic fibers and no plastic additives, or invest in reusable tea bags for use with loose tea leaves.
Avoid heating food in plastic containers.
Do not microwave your food in plastic containers. Heating food or water in plastic containers causes the plastic to break into tiny microplastics. You should heat your meal in a glass or ceramic container.
Fix a laundry filter
One of the ways microplastics enter the ecosystem is through laundering. Every time we wash clothes, tons of synthetic fibers pass through the sewage to the marine and terrestrial ecosystems.
Most wastewater treatment plants fail to filter these microscopic particles out. Further, the sewage sludge resulting from wastewater treatments has been found to contain millions of microplastic particles which end up used as fertilizers.
To avoid this, install a laundry filter inside your washing machine and dryer. It keeps microplastic fragments from washing into the environment. Apart from keeping the environment safe, it also helps your washing machine to last longer.
Environmental science experts are helping us learn about the environmental impact of microplastics. Now, we know the extent to which we are causing damage to the planet and our health with the way we use plastics.
Microplastics are not visible to the naked eye, so we don't know when we ingest or inhale them. It is in our best interests to take precautionary steps in reducing plastics in our surroundings because it guarantees safer earth for all of us.
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