It starts like a script for a sci-fi movie. An unseen threat, nearly invisible to the naked eye, looms over the planet and all its inhabitants. No matter how tiny, they’re found everywhere, operating in the shadows: textile microfibers.The term microplastics is used to designate elements that are smaller than 5mm, whereas the term microfiber, in textiles, indicates a weight of less than 1 decitex. With fiber production having doubled over the past 20 years, going from 58 million tonnes in 2000 to 113 million tonnes in 2021, a causal link is rapidly being established, along with the growing risk of generating more microparticles.
A global impact
Transported by wastewater discharges, wind or systems such as dryer vents, textile microfibers are found on the earth’s surface, in the air and in water, causing contamination that affects even the most remote environments.
A University of California study revealed that 176,500 tons of synthetic microfibers find their way onto the land each year, compared to 167,000 tons that accumulate in water. So they are effectively everywhere.
Read also: All you need to know about biodegradability
Synthetics, a toxic invasion
When addressing the concerns around microfibers, the plastic particles emitted during washing are the most documented. And the concern is justified. In 2021, synthetics will account for 64% of fibers used, with polyester alone accounting for 54%. As they steadily colonize the surface of the globe, the sheer ubiquity of synthetics underscores concerns about their persistence in the environment.
In soils, their deterioration by means of physical, chemical and biological processes spurs the release of various chemical compounds, including the additives and colorants from which the products were made.This deterioration is accompanied by slow and partial mineralization on the earth’s surface.
In urban areas, it’s the wastewater that is the most heavily contaminated with plastic microfibers. During wastewater treatment in sewage treatment plants, the finest particles pass into the liquid effluent, but most of the microplastics are trapped in the sludge, which is then used as fertiliser.
This is why agricultural compost and irrigation water are a source of microplastic contamination of soils.
The breakdown of microplastics produces nanoplastics and numerous molecules that modify the makeup of the soil itself. Once buried, these nanoplastics and molecules disrupt microbial activity and migrate to the water table. The toxicological impact on the organisms ingesting them may account for phenomena including oxidative stress, free radicals affecting development, disrupted endocrine systems, or can be reprotoxic.
Fibers under surveillance
While synthetics are rightly a cause for concern, the focus should now be on all types of fibers, whether natural, artificial or synthetic.
Pre-treatment, dyeing, printing, finishing – all fibers undergo multiple chemical transformations to allow them to take on different characteristics. Although this is how they acquire their color, strength, softness, ease of maintenance and fancy look, such additives are not without impact.
Recent studies reveal that it is not only the fibers themselves that cause problems, but also the chemical cocktail in which they are soaked and which may be even more harmful to biodiversity.
So, we have to be careful about taking shortcuts when it comes to the naturalness of a fiber and its non-impact on the environment. A natural or animal fiber, while initially biodegradable in its raw state, will not necessarily have the same impact and ability to disappear as its final-product version. All the characteristics of a material, the environmental conditions, the milieu (fresh water, sea water, soil) affect the potential and rate of biodegradation.
From manufacturing to care and maintenance
Washing synthetic textiles is thought to contribute up to 35% of the microplastics found in the ocean. However, the fragmentation of textiles is a complex phenomenon, and doesn’t only take place during their maintenance or care. Many studies point to a loss of fibers from the manufacturing stages on through all the phases of use. The structure of the yarns and filaments, the kind of weave or knit, the mechanical transformations and chemical treatments lead to a fragmentation of the fibre throughout its life cycle.
The release of microfibers is especially important during the first washing. Fibers can have pre-existing damage, caused by mechanical and chemical stresses during spinning, fabric manufacturing and dyeing, leading to multiple contacts with metal parts that have hurt the fibers. These fragments are amalgamated into the yarn and are likely to be released in the first wash with the force exerted on the material.
Given the multi-faceted nature of the problem, how can we prevent this invisible invasion?
Smart Key #1: Standardize measurements
The number of studies is increasing; yet even with quantified data, there is a lack of comparability. In the absence of harmonized international methods for conducting the analyses, results can vary from one to four times depending on which reference system is used.
Fiber fragmentation occurs on a very small scale, so any method must be able to evaluate small values with a high degree of accuracy. An international standard, ISO 4484, is now being consolidated. Set to be published in 2023, this standard it will make it possible to align observation frameworks for evaluating synthetic fiber losses under standardized washing conditions, a first step towards the standardization of fiber-loss measurements.
Smart Key #2: Strengthen filtration
The guidelines published by the Microfibre Consortium provide support for identifying the actions to be implemented during manufacturing, in particular strengthening filtration stages in the upstream phases. The use of more advanced filtration technologies would be all the more convincing as these could also promote the overall purification of water and encourage its recycling.
To date, wastewater treatment plants do not fully eliminate microparticles, so the objective is to reduce their quantity as much as possible before they enter the wastewater stream.
According to researchers, preventing microfiber emissions at the source, by minimizing the use of synthetic fibers, using a filter on individual machines, and using gentler wash cycles, would be more effective than trying to capture the fibers later.
Large-scale removal of microparticles from the environment is both technically difficult and economically unviable given the scale of the task.
The installation of microfiber filters could reduce the amount released during a wash cycle by up to 80%.
Note that on the consumer side, in France, the AGEC law (Anti-Waste and Circular Economy) requires new washing machines to be equipped with a plastic microfiber filter as of January 2025.
Smart Key #3: Explore innovation
Given the scope of the issue, research and development is focused on analysing the factors that can reduce the fragmentation phenomen.
Reviewing the options for texturization filaments, the types of yarn construction, testing different kinds of weaves and knits to select those that generate the least microfragments, reducing the number of polymers and additives, along with the reduction of non-essential treatments, should all be considered.
Developing lower-impact synthetic polymers with improved biodegradability would also reduce the impact of microparticle releases. It should however be underlined that innovations qualified as biodegradable are as such most of the time, and under particular conditions, which has to be communicated transparently. They generally require industrial installations, for example, to maintain the high temperatures (>50°C) required for the chemical and biochemical reactions necessary to their transformation. This point also raises the need to consolidate adequate treatment structures at the community level.
- Textile Research Journal – Alma Palacios-Mar, Abdul Jabbar and Muhammad Tausif – Fragmented fiber pollution from common textile materials and structures during laundry (2022)
- Ekaterina Vassilenko, Mathew Watkins, Stephen Chastain, Joel Mertens, Anna M. Posacka, Shreyas Patankar, Peter S. Ross – Domestic laundry and microfiber pollution: Exploring fiber shedding from consumer apparel textiles (Juillet 2021)
- The Microfibre Consortium – Preliminary Guidelines: Control of Microfibres in Wastewater (Mai 2022)
- Institut de France – Rapport de l’académie des sciences – Les plastiques dans l’environnement (Mars 2021)