Look around you and try to count the number of plastic items in the room.
I’m guessing that it’s nearly impossible.
Nowadays, plastics are used for everything from coffee cup lids to televisions to iPhone cases— even when things aren’t obviously made of plastic, they frequently utilize plastic components. There are understandable reasons for this ubiquity—plastics are durable, moldable, and can be endowed with different useful properties. But this widespread usage comes at a price. While many of us know that plastic production contributes to greenhouse gas emissions, fewer realize the impact that plastics can have after manufacture.
I’m talking, primarily, about microplastics, which are increasingly discussed among scientific communities, but still largely unknown. So what are microplastics? According to the National Ocean Service, microplastics are “small plastic pieces less than five millimeters” which have entered the ecosystem. Although microplastics are everywhere, the environment they eventually enter is usually the ocean. But given that hardly any plastic products are so small—one millimeter is about the size of the head of a paperclip—what causes microplastics to form?
In a word: biodegradability. Or rather, the lack thereof. Biodegradation is the time it takes for a product to be consumed by bacteria or other living things, and thus returned healthily to the ecosystem. Traditional plastic has one of the longest biodegradability time periods: for instance, plastic water bottles take over 450 years to decompose while in landfills. And other, thicker plastic products can take over 1000 years to biodegrade! So when plastics enter the ecosystem, they tend to stay there, breaking down into ever-smaller pieces.
There are two main types of microplastics: primary microplastics and secondary microplastics. It’s worth discussing each type before turning to a larger exploration of microplastics and the environment.
Pick Your Poison: Primary and Secondary Microplastics
Primary microplastics are plastics that are “intentionally” under 5 millimeters in size. These typically include things like fibers and nurdles. Fibrous microplastics come from materials like Nylon and Polyurethane (PET). Think, for instance, of a jacket that was made of plastic bottles, or an item of furniture incorporating plastic fibers to increase softness. When these items are washed or thrown away, these fibres “shed” and enter the general environment. In fact, a single washing cycle can shed 700,000 fibres!
Nurdles are a bit different. Essentially, whereas plastic fibers are long and skinny, nurdles are akin to tiny plastic beads. And, in fact, cosmetic “microbeads” are the paradigmatic example of nurdles! You’ve probably encountered cosmetic microbeads before—anything in a skincare product that’s beadlike and designed to exfoliate is likely a cosmetic microbead. If not, here’s what they look like:
In the United States, microbeads are actually banned from cosmetic use, for reasons I’ll discuss soon. But nurdles and microbeads are still prevalent in other products, and in other areas of the world.
Now that we’ve examined some of the types of primary microplastics, let’s delve into secondary microplastics. Secondary microplastics arise when plastic products are discarded, but fail to actually decompose. However, this doesn’t mean that discarded plastic products aren’t breaking down. In fact, they are… and that’s the problem.
When plastic breaks down due to erosion or natural wear, that’s not the same as biodegradation, which comes from organic consumption. Essentially, microorganisms like bacteria consume tiny amounts of a material, returning it to the natural world. This time-series of a plastic biodegradable plastic bottle serves as a good example:
In the case of mere break-down, parts become smaller, but are still “pieces of plastic,” and as such cannot be consumed by microorganisms.
While furniture, clothing, and cosmetics are the main sources of primary microplastics, secondary microplastics have a wider variety of origins. Typically, large and thick plastic items are more likely to turn into secondary microplastics. These include water bottles, building materials, cooking utensils, footwear, and tires.
Interestingly, secondary microplastics contribute far more to the overall amount of microplastics in the environment, as measured by tonnage. It’s estimated that over 90% of all microplastics actually come from secondary microplastics.
Now that we’ve examined what microplastics are and where they come from, let’s talk about how they infiltrate and impact the environment.
The Heart of the Issue
There are three primary ways in which microplastics enter the aquatic environment and become environmental pollutants. First, plastic waste is often discarded into landfills. Unfortunately, improper upkeep, or just the general realities of erosion, sees this waste broken down until it becomes microplastic. At only 5 millimeters or less, it’s almost impossible to stop this material from being transported via wind or rain towards drainage channels that lead towards rivers, and, eventually, the ocean.
Another major contributor is littering. Only a small fraction of plastic is actually recycled (around 1 to 2%). Of the remainder, what’s not taken to a landfill is often simply thrown into the ocean. This is particularly true in countries with less stringent environmental regulations. It’s estimated that, of the 14 billion pounds of trash generated every year, a majority is plastic that is eventually dumped into the ocean.
The third path towards microplastic pollution is through drainage systems—think shower and toilet drains. As mentioned earlier, many cosmetic products contain microbeads. When these products are washed or flushed through these drainage systems, microbeads have a high likelihood of entering natural waterways. You’d be surprised how frequently this occurs—for instance, check out this small selection products that have been known to contain microbeads. I’d be willing to bet that almost everyone has used one of them at one point!
Microplastic deposited into the ocean through these three channels has accumulated significantly over time. There are now “5.25 trillion or more micro pieces of plastic in our ocean, and every day around 8 million pieces of plastic makes their way into the oceans.” So given that we’ve examined the nature and cause of microplastics, it bears asking: what does the immense amount of microplastic in the ocean do?
The Big Impacts of Microplastics
Unfortunately, aquatic microplastic has a number of pernicious effects. One of the most widely discussed issues is the potential for ingestion. Animals frequently mistake plastics for food, or consume plastics that have become absorbed into foods within their natural diet. Plastics can even “smell” like food to marine life. This issue recently made headlines after a study found that microplastics could be found in the guts of every known species of turtle. Mussels, worms, fish and seabirds are also commonly affected. Even plankton have been showing signs of microplastics consumption.
When plastics are ingested, there are a number of adverse health impacts for marine life. This can include disease, hormone dysregulation, or even death. But microplastic ingestion doesn’t just hurt the directly affected animal. It also hurts ecosystems as a whole. For instance, if the population of one species is decimated from microplastics ingestion, the other animals which rely on that species for nourishment may also be affected.
And, further, it might not just be aquatic life that’s affected. One study found that, in humans, “annual microplastics consumption ranges from 39000 to 52000 particles depending on age and sex.” Plastic water bottles are a major contributor, and those who exclusively drink bottled water may consume an additional “90000 microplastics annually.” Increasingly, researchers worry that we might be affecting our own health as well.
Further, microplastics can leech contaminants into the aquatic environment. Even if plastic does not biodegrade, it can still bleed chemicals like DDT and PCBs into the water. These chemicals, of course, themselves have a number of environmental concerns.
Finally, microplastics can “latch” on to other (plastic or non-) items, essentially worsening the patches of garbage which already interfere with the natural ecosystem. Many of us have heard of the Great Pacific Garbage Patch, but fewer have actually considered its extent. While it’s not possible to precisely measure the size of the patch, it’s at least the size of Texas—and at most the size of Russia. Microplastics “contribute” a significant amount to the patch. It’s estimated that 25% of the total mass of the garbage patch is made up of microplastics. And, in purely numerical terms, the vast majority of plastic debris in the patch is micro- in nature.
What Can Be Done?
Because microplastics primarily come from the buildup of plastic debris, there are two main avenues for improvement. First, the amount of plastic waste that is introduced into oceans can be decreased. This can be accomplished largely through behavioural change. For instance, as mentioned earlier, Americans only recycle around 1-2% of plastic, which means that a huge amount of plastic is thrown away or littered. From that point, it can break down, be carried by water, and enter the ecosystem.
Compounding the issue is the fact that much plastic usage is entirely unnecessary. For instance, bottled water has not been demonstrated to be cleaner than normal tap water. In fact, it’s estimated that around 25% of bottled water is tap water. Another common source of unnecessary plastic waste is plastic cutlery. Although it can be a pain to wash metal forks and knives, they are far more environmentally friendly than plastic materials which are only used once. Of course, these are just two of many examples. Looking around the room again, you can probably identify other plastic items that are wasteful.
Behavioral change at the individual level is helpful. But it’s potentially even more impactful when individuals come together to demand change at a corporate or political level. One exciting, recent example of this was the pressure put on Starbucks to stop using disposable plastic straws. This activist movement actually compelled Starbucks to stop using these straws in 2020, saving an estimated billion straws per year.
The other main avenue for change comes through technological advancement, which can help address microplastic pollution in several ways. For instance, biodegradable plastics technology can allow products to break down naturally, as demonstrated in the image of the bottle shared earlier. As technology advances, these products become more economical to use, and they also biodegrade more quickly and completely.
There are also other, less obvious technological advancements that can potentially help. For instance, scientists have recently found a way to utilize bacteria to reduce the abundance of microplastics. These bacteria essentially consume microplastics, forming a sticky biofilm that is recyclable and less environmentally harmful than the diffuse plastic particles.
Finally, it’s quite difficult to monitor microplastics, given their small size. But monitoring is highly important—without good ways to know the extent or location of an environmental problem, the problem becomes far harder to address. Fortunately, there have been advances in this area too. And the scientific community is coming together to meet the challenge. In 2020, for instance, the EU’s Joint Research Commission introduced a large scale study to try and identify best practices and standards for measuring microplastics.
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