Where do microplastics come from?

Synthetic textiles are the single greatest contributors to engineered microplastics in the ocean, accounting for 35 percent of the total volume.

Polyester, nylon, acrylic, and other synthetic fibers – each a form of plastic – make up 60 percent of the fabric content of our clothes. Why? Synthetic microplastic fibers are cheap and versatile. The fibers create stretch and breathability in activewear, and warmth and sturdiness in winter clothes.

But washing synthetic textiles frees engineered microplastics through abrasion and shedding of fibers from the fabrics. That’s due to the mechanical and chemical stresses that fabrics undergo during a washing process in a laundry machine.

Your plumbing sends the spent water from your washing machine to a wastewater treatment plant. These fibers, too small for the plant to filter, are discharged with treated wastewater. The fibers eventually find its way to the oceans.

Natural fabrics like cotton shed too. But while many natural fibers biodegrade, synthetics don’t.

Things were so much simpler when tires were made of wood.

Today, about 24 percent of a tire consists of synthetic rubber, a plastic polymer, and 19 percent natural rubber. Microplastics form a matrix of the synthetic polymers, giving the tire both rigidity and traction. The rest of the tire is metal and other compounds.

Tires erode through heat and friction from contact with the road. The wind and rain spread the tire dust and wash it off the road. It enters tributaries, lakes and eventually the oceans.

A Canadian study found that passenger light truck tires lost nearly 2.5 pounds of rubber during an average service life of just over 6 years. Another study found that Americans produce the most tire wear per capita and estimated that tires in the U.S. alone produce about 1.8 million tons of microplastics annually.

Second only to synthetic textiles, vehicle tires contribute 28 percent of all the primary microplastics in the oceans, according to the IUCN.

City dust, which accounts for 24 percent of microplastics in the oceans, comes from a variety of sources. While each is a small contributor, it adds up in a populated area.

Weathering, abrasion and detergents create city dust from manmade products.

City dust includes losses from the abrasion of objects like synthetic soles of footwear and synthetic cooking utensils, the abrasion of infrastructure like household dust, artificial turfs, harbors and marina building coatings. It also includes particles from the blasting of abrasives, weathering of plastic materials and use of detergents.

Scientists recorded 365 microplastic particles per square meter falling daily from the sky in the Pyrenees Mountains in southern France. That was 60 miles from the nearest city. The authors of the 2019 study called it a “new atmospheric pollutant.”

Crews apply road markings while building and maintaining roadways. The substances used include polymer tape and paint. Thermoplastics are popular in Europe.

The loss of microplastics may result from weathering or abrasion by vehicles. The materials are either spread by wind or washed off the roads by rain before reaching surface waters and potentially the oceans.

Debris from road markings make up about 7 percent of the primary microplastics in the ocean.

Operators apply marine coatings to all parts of seagoing vessels for protection. That includes the hull, the superstructure and on-deck equipment. The materials involve solid coatings, anticorrosive paint or antifouling paint.

Developers use several types of plastics for marine coatings, including mostly polyurethane and epoxy coatings, vinyl and lacquers. Weathering and spills during application, maintenance and disposal of these coatings cause the release of primary microplastics.

Marine coatings account for 4 percent of primary microplastics in the ocean.

Many personal care and cosmetic products contain a type of engineered microplastic known as microbeads. The products include scrubbing agents, shower gels and creams.

The U.S. government banned its manufacture and sale, but producers still make and sell these products globally.

Microbeads are manufactured polyethylene plastic. It acts as an exfoliant, delivers active ingredients, and controls viscosity in health and beauty products.

Up to 10 percent of some personal care product’s weight is plastics. That’s more than the packaging material. Some items have several thousand microbeads per gram of product.

Once the personal care item is used, it ends up in wastewater. These tiny particles easily pass through water filtration systems and end up in our waterways.

Personal care products and cosmetics represent 2 percent of all primary microplastics in the oceans.

Manufacturers produce several plastics in the shape of pellets or powders, the primary form of plastic. These producers then transport the pellets to plastic transformers that make plastic products. Pellets can inadvertently spill into the environment during manufacturing, processing, transport and recycling.

Plastic pellets make up 0.3 percent of the ocean’s primary microplastics.

In 2019, the State of Texas fined a Texas plastic manufacturer of more than $120,000 after spilling thousands lentil-sized plastic pellets or “nurdles” into a creek and bay on the Gulf Coast. Formosa Plastics, a Taiwanese company headquartered in New Jersey spilled the nurdles near the company’s 2,500-acre complex, about halfway between Houston and Corpus Christi.

The state required the company to recover and properly dispose of about 439,000 pounds of debris and plastic from the waterways.

Nurdles can absorb dangerous industrial and consumer chemicals including insecticides, PCBs and mercury. The pellets can clog the digestive systems of marine animals if ingested for food, and eventually cause them to starve to death. Nurdles can also degrade into microplastics.

Texas is a major producer of plastic pellets.