Plastic debris comes in many different shapes and sizes, but those that are less than five millimeters in length are generally defined as “microplastics.” Microplastics come from a variety of sources, often from larger plastic debris that degrades into smaller and smaller pieces. Natural processes, including sunlight, cause fragmentation, which makes the material brittle and causes it to break. Microplastics can keep breaking up until they are dust particles that are difficult to measure and nearly impossible to separate from the environment.
Some microplastics have been made small intentionally, like industrial abrasives used in sandblasting and, despite a growing number of bans across the globe, microbeads in facial scrubs. All these tiny particles easily pass through water filtration systems and end up in lakes, rivers and oceans. While scientists are not unanimous on the degree of severity, there is general consensus that microplastics pose a potential threat to both humans and wildlife.
Microplastics and the environment
There are wide-ranging concerns about the impacts of microplastics on our environment, in particular on marine wildlife. Sharks, whales, seals, sea turtles and polar bears are vulnerable to microplastic ingestion in the oceans throughout the world. These animals ingest large amounts of microplastic either directly swallowing from ocean water or indirectly by consuming prey containing microplastics in their body cavity. The harmful effects of microplastic ingestion is also an issue of concern for sea birds as half of the species are endangered and the toxic effect of plastic fragments has negative effects on their body which could cause alteration in feeding behavior, reproduction and mortality.
There is growing evidence that fish who are exposed to significant levels of microplastic have stunted growth and altered behavioral patterns, such as ignoring the smell of predators and choosing to eat plastics over their primary food source (zooplankton). Zooplankton, the cornerstone species of the marine food chain, are also heavily impacted by microplastic particles. When zooplankton feed off of these tiny particles, they pass them on to their natural predators, particularly salmon and other large fish species. Plastic comes as an easy snack for zooplankton which leads to an increase in the concentration of plastic particles species higher up on the food chain.
In addition to blocking the digestive tract in some species which leads to starvation, microplastics may also leach chemicals into the bloodstream that could potentially cross the blood-brain barrier and lead to neurological damage. There is evidence, at least in animals, that microplastics can cross the hardy membrane protecting the brain from many foreign bodies that get into the bloodstream. Additionally, mothers may be able to pass microplastics through the placenta to a developing fetus.
Microplastics and humans
It is difficult to completely assess the risks microplastics may pose for humans as each plastic is made up of a unique combination of chemicals. Plastics also come in different shapes, sizes and textures, all of which influence their level of toxicity.
For anyone living in the United States, plastic is nearly impossible to avoid: It lines soup cans, leaches out of storage containers, hides in household dust, and is found inside of toys, electronics, shampoo, cosmetics and countless other products. It’s used to make thousands of single-use items, from grocery bags to forks to candy wrappers. But what many people don’t know is that we’re doing more than just using plastic. Over time, microplastics make their way into our food and water as the tiny particles break off into our meals.
One 2019 research review published by the American Chemical Society calculated that just by eating, drinking and breathing, Americans ingest at least 74,000 microplastic particles every year. Another recent study commissioned by the World Wildlife Fund and conducted by researchers at the University of Newcastle in Australia estimated that people consume about 5 grams of plastic a week.
It’s possible that ingesting microplastic particles could further expose us to chemicals found in some plastics that are known to be harmful, such as bisphenol A and phthalates (pronounced tha·leit). Bisphenols are known to interfere with hormones, and there are studies linking bisphenol exposure to reduced fertility in men and women. Phthalates are also known to disrupt hormones, and prenatal exposure to phthalates can cause lower testosterone in male offspring. Styrene, another chemical found in plastic and some food packaging, has also been linked to a number of health issues, including nervous system problems, hearing loss and cancer. Microplastic particles can also accumulate polychlorinated biphenyls (PCBs), other chemicals that are linked to harmful health effects, including various cancers, a weakened immune system, reproductive problems and more.
What can you do to reduce microplastics?
There is quite a bit that we can do to reduce microplastics. The most important step lies in changing the way we think and behave. Wherever you live, the first thing you should do is reduce your own use of single-use plastics. Single-use plastics include plastic bags, water bottles, straws, cups, utensils, dry cleaning bags, take-out containers, and any other plastic items that are used once and then discarded. Some alternatives to these single-use plastics include: stainless steel straws, reusable glassware, and utensils made from bamboo. By investing in quality reusable products, you’ll protect the environment and save yourself and your family money.