Undesired fibres: Microplastics released from textiles

A large volume of microplastics from sports and outdoor textiles enters the water cycle through washing. It is possible, however, to take countermeasures as early as the production stage. Consumers, too, can take measures themselves. Nearly everyone has outdoor or sports clothing in their wardrobe – it is comfortable, versatile and usually low maintenance. Laundering textiles made of plastics or plastic mixtures, however, causes microplastics to enter the water cycle. While reliable figures on this are not yet available, there are credible estimates: About 20 to 35 per cent of all microplastic waste comes from textiles. This mostly occurs in the form of fibres. They can be particularly harmful because fibres cause, among other things, entanglement in the digestive tract of animals. What can we do to reduce this environmental pollution? This was the question addressed by the TextileMission project in the "Plastics in the Environment" network.

The project team tackled the problem from different perspectives. One important goal was to find out how much microplastic actually enters the wastewater through typical household laundry: It is up to a total of 300 milligrams (mg) per kilogram of textiles in the first wash. Over the course of 10 washing cycles, up to 1000 mg can be emitted – 99 percent of which is polyester. The following detailed findings are interesting: 40 to 60 percent of microplastics are emitted during the first wash. This is mainly due to the fact that production residues are found in new goods, for example due to the abrasive effect of the knitting needles. In addition, the goods may have been contaminated during transport. Each textile was washed at least 10 times during the experiment, while some items were subjected to additional wear tests and up to 30 care cycles to simulate wear as close to real life conditions as possible.

An important parameter for microplastic discharge was the machine load. In the first wash cycle, it was twice as high when 1.5 instead of 3.5 kilograms of laundry were washed. The reason: the lower the load, the greater the mechanical stress on the textiles. Therefore, filling your machine efficiently is good for both your wallet and the environment.

Sewage treatment plants can process the majority of these microplastic fibres. The TextileMission team found that in Germany more than 90 per cent of these fibres are filtered out. Naturally, this only works if the wastewater from the household actually makes it to the sewage treatment plant. According to project estimates, a total of between 42 and 979 tonnes of PET from household laundry enter the sewage treatment plants in Germany every year - an enormously high figure. Given the retention in sewage treatment plants, this still means that between 2 and 47 tonnes of microplastics are discharged into nature. Optimised production with downstream purification could provide a remedy. However, it would have to be ensured that the microplastics are completely filtered out of the process water and disposed of properly. This is the responsibility of the manufacturers and the globally producing labels.

Another TextileMission team dealt with the question of which alternative fibres can improve the environmental balance of sports and outdoor textiles while reducing the microplastic problem. The researchers analysed whether recycled PET and regenerated cellulose fibres (viscose, Modal, Lyocell) have the potential to be a more sustainable alternative to virgin polyester in terms of raw material extraction, production and disposal. The answer is yes - but it depends on specific conditions such as cultivation and production location, mode of operation, energy mix and waste management. Recycled polyester can have sustainability advantages in production compared to virgin polyester, however, it also contributes to the microplastic problem. Cellulose regenerated fibres are produced from naturally occurring, renewable raw materials, but their production requires chemical processes. They are biodegradable under specific environmental conditions and thus offer the possibility of reducing microplastic emissions into the environment. Another idea for future outdoor fabrics is to develop textiles that emit fewer microplastic fibres and contain fewer additives, such as dyes.

The scientists also tackled the question of how consumers can contribute to a lower textile microplastic input into the environment. Their recommendations were to avoid fast fashion and to buy fewer and more durable textiles and even to buy second-hand clothes. And to make sure that no textile waste ends up in the environment, for example by donating clothing that is no longer used to social clothing centres, second-hand shops or charity clothing containers.

The results described here were presented at a webinar of "Plastic in the Environment" on 26.8.2021. More information on this, all presentations and further links at https://bmbf-plastik.de/de/veranstaltung/webinar-4-Plastikemissionen-in-der-Textilindustrie.

*Photo: Lena Aebli, Ecologic Institut

**Written by Wiebke Peters