Microplastics are all around us, and yet many people don't know what they are — or how prevalent they are. Though studies have yet to reveal a tangible effect on humans, plastic debris can be destructive to marine habitats. Ultimately, we all share this planet, and global ecosystems influence each other — what happens in one will eventually find its way to another.
Preventing further ecological harm benefits every living being, from zooplankton to humans to blue whales. Microplastics are a major environmental threat despite their tiny size, but they don't have to continue affecting the environment if we all think big and act quickly.
Microplastics are small plastic particles less than 0.2 inches (5 millimeters) long, according to the National Oceanic and Atmospheric Administration (NOAA). For a visual representation, think of a sesame seed. Now imagine millions of sesame-seed sized plastics floating in the ocean every day, with more continually added from various sources. In 2014 alone, researchers estimated there to be up to 51 trillion pieces of microplastics in the ocean. This quantity outnumbers the stars in the Milky Way by 500 times.
In contrast, macroplastics are larger objects like plastic bottles, hair combs, and toothbrushes. Both types of plastic continuously flow into the ocean, but microplastics prove much more challenging to remove due to their small size. Volunteers can easily pick up large items during beach cleanups, but microplastics are often too small to spot or grab in moving water.
Researchers study microplastics by using plankton nets, which have mesh netting that measures 0.004 to 0.02 inches (0.1 to 0.5 mm) — small enough to capture plastic particles. Others conduct visual surveys, though this method can be hard to use because of the variation in techniques.
How are microplastics made? Microplastics often originate from macroplastics that have broken apart in the ocean. Plastic may break apart due to weathering from the sun, wind, or other causes. The microbeads in many personal care products — such as toothpaste and facial scrubs — also count as microplastics. Microbeads often consist of polyethylene plastic, though they may also contain polystyrene or polypropylene.
Resin pellets, which are raw materials used in the process of manufacturing plastic, also contribute to the overall amount of existing microplastics. Pellet loss during the manufacturing process can introduce these particles into natural environments, where they cause a range of adverse outcomes. These pellets — commonly called "nurdles" — were sources of E.coli and a pathogenic Vibrio bacteria on five public bathing beaches included in a recent study.
Microplastics also come from synthetic clothing. If you see these names the next time you go clothes shopping, you know those products are human-made:
Whenever you wash these fabrics, they release some of their threads, which get carried away in the water that drains out of the washing machine. Wastewater treatment facilities remove much of these microplastics, but there is always a percentage that makes it into the water system.
Microplastics hail from a range of sources, which subsequently means that there's no single solution for decreasing their spread. Instead, a combination of land-based and aquatic efforts is necessary to stop this form of pollution.
Why are microplastics a problem? Though they are small, these bits of plastic bring similar issues that macroplastics do — plus their own set of harms. These small particles serve as carriers for bacteria and persistent organic pollutants (POPs). POPs are toxic organic compounds that, much like plastic, take years to degrade. They consist of chemicals like pesticides and dioxins, which are hazardous to human and animal health in high concentrations.
POPs biomagnify as they move up the food chain, meaning that larger animals accumulate more of these toxic substances within their fat and tissues than smaller organisms. Naturally, this leads to a more prominent risk factor for large marine creatures and humans. Consuming plastic itself is harmful to marine animals, but ingesting bacteria-ridden plastic — or materials containing POPs — could be fatal.
POPs aren't very water-soluble, meaning they don't dissolve easily. Because of this quality, it's easy for them to accumulate within aquatic sediment and create toxic reservoirs. These deposits don't pose too much danger if they remain undisturbed — but there's always a chance that they could be. It's more beneficial for our ecosystems to eliminate their presence than rely on the hope that these chemicals won't be re-released into the ocean.
Aquatic communities aren't the only ones significantly affected by plastic debris. Microplastics also introduce a range of issues into land-based ecosystems, as communicated by a German study:
Because plastic debris often serves as a bacterial vector, non-native bacteria may enter freshwater ecosystems and wreak havoc on the pre-existing balance between living beings. Organisms may suffer from diseases that they have no prior immunity against. This material spells trouble for every aspect of an ecosystem, from the smallest creatures to the biggest.
Scientists are still drawing a comprehensive picture of how microplastics affect marine creatures. Research is in this area is relatively new, and ongoing studies are helping researchers form conclusions about the dangers of microplastics on aquatic life. In addition to bacterial growth, many microplastics enter the ocean with their own set of harmful additives from the plastic manufacturing process.
Microplastics may contain fillers, colorants, flame retardants, and many more chemicals as a result of plastic processing. The rate of diffusion — or the spreading of a substance — isn't the same for all of these chemicals, meaning some of them may pose less of a risk to marine creatures than others. However, if an animal ingests enough microplastics, they may be exposed to high concentrations of a particular substance.
Scientists have found notable amounts of microplastic debris in the waste of Northern Fulmar seabirds — 47% of the fecal precursor samples they tested contained microplastics. Through these findings, they've suggested that these seabirds are acting as vectors for plastic debris within their native colonies. By introducing plastic particles into the environment, the birds may be creating a halo effect, where plastic levels are higher the closer you get toward the colony.
Macroplastics can cause animals to feel full even when they're receiving no nutritional content, which can lead to starvation. Though this is less of a problem with microplastics, seabirds may still be at risk for death due to chemicals or bacteria colonies on the plastic they ingest.
A 2016 lab-based study from the Royal Melbourne Institute of Technology (RMIT) University and Hainan University showed that plastic contaminants transfer up to 12.5% of their chemicals to the fish that eat them. Fish that ingested microbeads showed high levels of polybrominated diphenyl ethers (PBDEs). PBDEs can also interfere with enzyme activity in the Pacific cod, which can cause significant DNA damage. The cod's enzyme system protects it from free radicals — which are unstable atoms — that can cause cell damage if left unchecked.
The study's scientists found that three PBDEs, in particular, affected enzyme activity in the Pacific cod:
Research conducted on the Oregon coast studied two species of shellfish — Pacific oysters and razor clams. Almost all 283 collected specimens contained at least one plastic particle except for one razor clam and one Pacific oyster. The study didn't yield a definite conclusion about how the microplastics affect the shellfish health-wise. Past research, however, has found that microplastics exist in the digestive systems of over 100 marine species, which poses chemical, physical, and biological harm.
The researchers did discover that specimens they collected in the spring had more plastics than ones gathered in the summer. That is likely due to the higher amount of plastic-based laundry from winter clothes, which sent synthetic microfibers into local waters. High precipitation rates during that spring also compounded plastic pollution by transporting more debris into the ocean.
One obvious way that humans ingest microplastics is through eating marine animals that have consumed the material. Even if you don't eat seafood, you have come into contact with microplastics at one point or another through your drinking water or the very air you breathe. Cars and trucks release 0.71 ounces (20 grams) of tire dust — which contains the plastic styrene-butadiene — for every 62 miles (100 kilometers) they travel on the road.
One New York study found that bottled water contained twice as many microplastics as the tap water samples examined in a previous study. This becomes even more concerning when you consider that 94% of tap water in the U.S. contains microplastics. Though these particles are tiny, they have infiltrated numerous aspects of human life, making them difficult to detect or avoid for the average individual. Other countries have also shown alarmingly high amounts in their tap water:
A recent study from the Environmental Science and Technology journal theorizes that human microplastics ingestion ranges between 39,000 to 52,00 particles annually, depending on sex and age group. These numbers only increase when we consider variables such as inhaled microplastics and tap water versus bottled water consumption.
How do microplastics affect humans? Though we have estimates of how many microplastics we ingest in a year, this question yields even less information than the material's effect on marine animals. Previous studies and trusted organizations, including the World Health Organization (WHO), have suggested that microplastics have no significant impact on human health.
Others propose that the type of plastic ingested or inhaled is what matters the most. For example, bisphenol A (BPA) has links to behavioral changes and increased blood pressure. PBDEs can cause endocrine disruption and neurodevelopmental dysfunction in humans, as well as liver and kidney damage.
Although these particles are pervasive, several microplastics solutions can slow the spread of plastic debris at the source. You can play a part in reducing the number of microplastics on land, in the air, and in global waters by shrinking your plastic consumption. Small acts add up, and you don't need to adopt every single lifestyle change mentioned here to make a difference. Doing just one of these a few times a week can aid in stopping the inflow of plastic:
In addition to the small steps you take at home, you can contact local lawmakers about what they're doing to stop the inflow of microplastics. For example, the Microbead-Free Waters Act of 2015 went into effect in 2017 and banned the manufacturing of any cosmetics containing microbeads. Making your voice heard within your community helps you and the people you share space with — a collective effort is the only path to success.
Education and collaboration are two of the most crucial aspects of winning the fight against the ocean plastic crisis. People can only act once they're informed, and moving as a collective heightens the impact of what we do. We have the power to stop microplastics at their sources and curb our plastic consumption — all it takes is one first step. No matter how you decide to participate, your contribution counts.
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