Polyester, a synthetic polymer made primarily from polyethylene terephthalate (PET), is a plastic widely used in the textile industry for its strength and low cost. The answer to whether polyester releases microplastics is definitively yes, as the material sheds microscopic fragments known as microfibers. These synthetic textiles now account for the majority of global fiber production, making the issue of shedding a pervasive and continuous source of plastic pollution.
How Polyester Fibers Become Microplastics
The primary mechanism for the release of polyester microfibers is the mechanical stress applied to the fabric during its lifespan, with laundering being the most significant contributor. The agitation and friction within a washing machine cause the fabric fibers to break and detach from the weave structure. A single synthetic garment can shed hundreds of thousands of microfibers in one wash cycle, releasing them directly into the wastewater effluent.
Polyester is particularly susceptible to this process because it has a lower abrasion resistance compared to natural fibers like cotton. The construction of the garment also plays a role, with knitted fabrics generally shedding more than woven ones due to their looser structure.
While washing is the main release point, microfibers also shed through everyday wear and tear, as well as during the drying process. A substantial portion of the initial shedding comes from residual fibers created during the fabric’s manufacturing and cutting processes. Higher water temperatures and increased water hardness during washing have also been shown to increase the rate of fiber fragmentation.
The Reach of Microplastic Pollution
Once shed from clothing, polyester microfibers enter the wastewater system, beginning a journey that affects ecosystems globally. Most fibers travel to wastewater treatment plants, but their small size allow a significant number to pass through the filtration systems. Even when captured, the microfibers often end up in sewage sludge, which is frequently used as fertilizer, thereby transferring the plastic pollution to agricultural soil.
The microfibers that escape treatment plants flow into rivers, lakes, and oceans, where they become integrated into the aquatic food web. Marine organisms, from zooplankton to fish and shellfish, mistake these tiny plastic strands for food and ingest them. This ingestion can cause physical harm, lead to false feelings of satiation, and facilitate the movement of microplastics up the food chain. Microplastics are also known to adsorb environmental contaminants like persistent organic pollutants (POPs) and heavy metals, effectively transporting these toxins into the bodies of ingesting wildlife.
Human exposure occurs through multiple pathways, including the consumption of contaminated seafood and drinking water. Additionally, microfibers are released into the air from clothing and household dust, leading to inhalation as a major route of exposure. Ingested microplastics are being researched for their potential to cause physical irritation and inflammation in the gastrointestinal tract. Specifically, they may compromise the integrity of the intestinal barrier, potentially leading to increased permeability and an inflammatory state.
Inhaled microfibers can reach deep into the lungs, where studies suggest they can cause inflammation and potentially impair the lung’s ability to repair itself. The particles can also carry leached chemicals, such as endocrine-disrupting additives used during plastic manufacturing.
Reducing Fiber Shedding and Choosing Alternatives
Consumers can take several practical steps to reduce the amount of polyester microfiber shedding from their laundry. Adjusting laundry habits can significantly mitigate the problem, as the mechanical action of washing is the primary driver of shedding.
Reducing Shedding During Laundry
Washing clothes less frequently, choosing shorter wash cycles, and using cold water all reduce the physical stress on the fabric. Opting for a front-loading washing machine, which uses less water and a gentler tumbling action than a top-loader, can minimize fiber release. Specialized microfiber-catching laundry bags or balls can be used in the washing machine to physically capture the released fibers before they exit with the wastewater. Installing an external filter device onto the washing machine’s discharge hose offers a more permanent solution for capturing a higher percentage of the microfibers.
Choosing Alternatives
When purchasing new items, consumers can prioritize apparel made from natural fibers like organic cotton, linen, hemp, or wool, which are biodegradable and do not contribute plastic to the environment. If synthetic materials are necessary, such as for high-performance activewear, some manufacturers are now engineering recycled synthetic fabrics that are designed to shed less. It is important to note that not all recycled polyester is equal, as some studies suggest that the process of recycling can sometimes result in a material that sheds more due to increased fiber brittleness.