The Society for Conservation Biology’s North America Policy Program
The world’s oceans are facing an unprecedented plastic crisis, and your morning routine may be inadvertently adding to it.
Plastic in the ocean is hard to track and quantities are growing every day, but scientists have estimated that concentrations can be as high as 580,000 pieces of plastic per square kilometer (223,880 per square mile). Plastic pollution has become so ubiquitous that over 90% of seabirds and most sea turtles have eaten plastics in their lifetimes, with numbers increasing every day. If you’re like me, you probably imagine that this plastic problem stems from the large pieces of debris we’re likely to see washed up on beaches such as plastic soda bottles, shopping bags, and lighters. But while large pieces of plastic debris are certainly an issue, this huge problem boils down to some much smaller pieces: microplastics. Microplastics are technically under 5mm in size (about half the size of a grain of rice). They can be a result of those larger pieces of plastic breaking down into smaller pieces over time, or can be the result of already small plastics entering waterway. This is where you and I come in, because we might be unwittingly contributing to the microplastic problem in local and global waterways simply by washing our faces or brushing our teeth.
I only realized that I was probably polluting plastic into the ocean when my friend and colleague, Dr. Chelsea Rochman, told me about her research. Chelsea is a marine ecotoxicologist and environmental chemist, and she specializes in studying how plastics get into our waterways and what the impacts of those plastics are on wildlife. She explained to me that microbeads- the tiny colorful spheres or flecks that you can see in many toothpastes and skin care products- are actually tiny pieces of plastic. Plastic?! I’ve been brushing my teeth with plastic? I immediately went home and examined the contents of my bathroom products. Face scrub, shower gel, toothpaste- almost all contained either polyethylene or polypropelyne, the two main plastics that are used for microbeads (polylactic acid, polystyrene, or polyethylene terephthalate are also used, but are less common). On my next trip down the personal care products aisle at the supermarket, I scrutinized the ingredient lists on the backs of most products and was shocked to see how many contained some form of microbead. Each bottle of face scrub can include thousands of microbeads, so it’s no wonder that scientists in Chelsea’s field are worried about the implications of these colorful bits of plastic on marine ecosystems. After learning about this problem and realizing how easily a change in our habits could plug the flow of some plastics into our oceans, my colleagues and I, all conservation biologists in the David H. Smith Postdoctoral Research Fellowship, decided to write a policy brief and scientific viewpoint paper to highlight what was known about the issue.
Microbeads are tiny troublemakers. They are so small that on average, 6 would fit across the thin edge of an American penny. Because of this small size microbeads not only wash down the drain in your home, but are too small to be trapped in the filters used in most wastewater treatment plants. Fortunately, the process that settles solids out of wastewater does also settle out up to 99% of microbeads, although we don’t really know the fate of those microbeads since sewage sludge is often land-applied so may runoff into waterways or enter terrestrial ecosystems. Even leaving 1% of microbeads in the final effluent, which is often pumped directly into waterways, is still a concern. We used a small existing dataset to estimate how many microbeads are entering waterways in the United States every day and the numbers were mind-blowing: Eight billion microbeads each day, and almost 3 trillion per year. If we lined up all of the microbeads released annually into waterways in the United States end-to-end, they would stretch around the circumference of the globe over 7 times. On top of this, microbeads are sold in personal care products all over the world and often in regions where wastewater treatment is less efficient and a greater proportion of microbeads may be pumped into local waterways.
Microplastics made from the same materials and of the same size as microbeads are found in virtually all waterways- bays, estuaries, shorelines, coral reefs, the deep-sea, freshwater lakes, rivers and even Arctic Sea ice. Not only do these plastics act like toxic sponges once they reach waterways, soaking up a cocktail of chemical pollutants, but they are mistaken as food by wildlife and can therefore enter the marine food chain. Microplastics of the same size and shape as microbeads have been found in marine wildlife including marine mammals, turtles, seabirds, fish and invertebrates. Microplastics may therefore have bioaccumulative effects in marine food chains and are likely to be making their way back to us in our food: a recent study by Dr. Rochman and her colleagues found that roughly 25% of seafood sold in markets in Indonesia and California contained plastic or fibrous materials in their guts.
Unlike many global environmental problems, microbead pollution offers a simple solution that many customers will appreciate: banning the bead. Microbeads are non-essential. They can be replaced with the traditional natural materials, such as oatmeal or pumice, which people have long used as exfoliants. Or, as my mom pointed out to me recently: “People invented a towel for that a long time ago, it’s even got a special name: it’s called a face-cloth”. To take the burden off of consumers, numerous states in the US and some countries are in the process of introducing or passing legislation to ban microbeads in personal care products. Through these actions we can at least ensure that our morning routines aren’t contributing to the already crushing amounts of plastic in our waterways.
Sara Kross is a David H. Smith Conservation Research Fellow and studies wildlife in agricultural systems. She tweets from @wildfarms