Microplastics — A Problem of Minuscule and Epic Proportions
by Judith S. Weis, marine biologist, Rutgers University
Plastic pollution is a clear problem in our world’s oceans, as well as fresh waters and land. Most of the studies to date have focused on the marine environment. The billions of pieces of plastic floating around in the ocean and accumulating on beaches and in “great garbage patches” have been documented by scientists, videographers, and photographers around the world. Effects of these plastics on marine life are generally well-known: entanglement and ingestion leading to an untimely death. Photos of marine wildlife tangled in plastic bags, 6-pack rings, or fishing gear are common, as are photos of autopsied dead whales or birds with their stomachs full of plastic.
But what about the plastics that don’t appear in the pictures because they are too small? Microplastics range in size from a few millimeters down to microscopic and come from a variety of different sources; some are a result of larger plastic pieces breaking up into progressively smaller and smaller pieces, some come from personal care products. A few years ago, the United States banned the use of plastic microbeads in personal care products (they were added to toothpaste, facial scrubs, etc. for abrasion.) Many non-plastic abrasive substitutes are available. They are also released when tires wear down , shedding tiny pieces on roadways, eventually washing into water bodies.
Microplastics are mostly invisible and everywhere. Initially, scientists believed they were solely a marine problem, since they were first discovered in the oceans. They thought that they floated, and so sampling was done near the surface of the water. However, this notion was very wrong. Microplastics are dispersed throughout the water column, all the way to the bottom — as deep as the seven-mile deep Marianas Trench. They are also trapped in Arctic sea ice. In rivers, lakes, and oceans the numbers reach the trillions, and quadrillions, and being plastic, they don’t break down. Furthermore, these tiny pieces act as magnets for chemical contaminants that may be in the water.
These tiny and sometimes contaminated pieces of plastic are eaten by small planktonic animals, as well as larger animals such as clams and oysters that eat by filtering the water. In some small species, microplastics can block the digestive system and limit the amount of “real” food these animals are consuming. Some marine animals, such as corals, actually prefer to eat microplastics over “real food.” Microplastics consumed by small marine organisms are then passed up the food web. Research in this relatively new field of study suggests that microplastics are harmful to the health and physiology of many marine species.
Since microplastics attract chemicals from the water, they provide a route for toxic chemicals to move into marine organisms. Furthermore, chemicals in the plastic itself may be available to the animals that consume it, going up the food web. And who sits on top of the food web? People. Undoubtedly, we all have microplastics in our tissues. Even if you don’t eat seafood, the sea salt that you might buy in a health food store has microplastics since it is produced by evaporating sea water. Microplastics are also in the air we breathe and the water we drink. (Incidentally, there are more microplastics in bottled water than in tap water — another reason to avoid bottled water).
By far the most abundant type of microplastic in our water tends to be long thin pieces, called microfibers (approximately 85% of the total). Where do these microfibers come from? Look no further than your laundry basket. Synthetic clothing sheds thousands of microfibers in washing machines, and these fibers are too small to be trapped in the filters of washing machines. Many will be captured at wastewater facilities after washing down the drain, but still billions will escape into the waterbodies including rivers down to the ocean. They come from not just fleece jackets, but nylon, polyester, rayon, acrylic and spandex. While some people are aware that there are environmental problems associated with growing cotton (e.g., water and pesticide use) few consumers are aware of the environmental problems associated with the production of synthetics.
So why should we care? How do these little fibers affect us? These fibers are being found as ‘fallout’ in our air, they are in our drinking water, and they have even been found in human lung biopsies. We should care because they have become ubiquitous. The potential for humans to ingest microplastics (and their adhering pollutants) in the seafood we eat is certain, but we don’t yet understand what this may mean for our own health.
The company Patagonia, which sells synthetic clothing, is very concerned and has been working on the issue. They funded a study that showed that top loading washing machines release many times more microfibers than front loaders, that washing in hot water releases far more than cold water, and that old clothes release more than new clothes.
One proposed solution for reducing microfibers is a device that can be put into washing machines to catch the microfibers at their source. But this would require individuals to buy the devices and clean them off periodically. What fraction of the population is likely to do this? It would be very small. In any case, these devices catch less than one-third of the microfibers. People are also talking about re-engineering washing machines so the filters would catch them. I am not an engineer, but have difficulty imagining how pores of a filter could be small enough to trap microfibers and not clog up very quickly. There is also an engineering problem in retrofitting 89 million washing machines currently in use in the U.S alone.
A large part of the solution should ultimately lie at the source of the problem — the manufacturing of synthetic fabrics (from petroleum, in case you didn’t realize that). Fiber and textile scientists have the knowledge and ability to help find ways to at least limit the shedding properties of synthetic fabrics.
Some projects that textile scientists are working on:
Develop technologies to trace microfibers in the environment back to specific brand and type of clothing from which they were shed. Using infrared spectrometer to determine the unique infrared “signature” of each fabric sample based on unique mix of dyes and additives.
Determine how many fibers are released by different types of synthetics and blends. Establish protocols to quantify fiber loss from particular fabrics, then set standards to keep fiber loss low via changes in manufacturing or construction, When apparel makers know which fabrics shed the most, alter approaches to yarn and fabric construction.
A workshop being planned, that I am part of, will include textile scientists as well as major clothing makers and retailers. A session I am co-organizing for the American Association for the Advancement of Science (AAAS) in February 2019 will bring together environmental and textile scientists and policy specialists to better understand how we can solve this global problem, one that is both tiny and enormous.
Judith S. Weis is a marine biologist, Professor Emerita at Rutgers University. Learn more and read more at: wisem.rutgers.edu/weis-judith