At first sight, fabrics made from synthetic fibers have many advantages. They are cheap, dry quickly, and shape themselves to the body. But they have become disposable articles and contribute significantly to climate change. They may also be harmful to human health.
Many of the garments we wear every day are made in part or entirely out of polymers. Consumers often do not know that terms like polyamide, polyester, acrylic and nylon actually refer to synthetic fibers — in other words, plastics. Such materials are popular among producers and consumers alike. They are elastic and dry quickly. They feel soft to the touch and weigh less than comparable clothes made from natural fibers such as cotton.
The polymers that are used to make chemical fibers fall into two categories. Those based on cellulose, such as rayon, are usually made from wood. Synthetic polymers, such as polyester, undergo several production steps, but ultimately they are made from crude oil or natural gas. In 2017, around 70 percent of all fibers produced globally were synthesized chemically. At 80 percent, polyester accounts for by far the biggest proportion of synthetic fibers, and production is rising steadily. In 2017, some 53.7 million tonnes were sold. About 94 percent of the material is produced and processed in Asia, mainly in China. About half of the polyester fibers produced go into clothing. Textiles — including industrial textiles, make up 15 percent of the world’s annual output of plastics.
The textile industry is a major polluter of groundwater, rivers and the sea. Between 20,000 and 40,000 different chemicals are used to process and dye clothing. Many of them are carcinogenic, alter the genetic code, and impair reproductive ability. They may also cause allergies and influence the hormone system. Known harmful additives include formaldehyde, the so-called perfluorinated chemicals, fire-retardants, and dyes and other additives. Workers are exposed to such contaminants at numerous points along the value chain. These substances also harm the people who live near production plants and wastewater streams.
The consequences are far-reaching. Many workers in the textile industry — some 70 percent of them worldwide are women — suffer from work-related illnesses. A link between formaldehyde and deaths due to leukaemia has been proven. Women who work with synthetic fibers in textile factories have a high risk of contracting breast cancer. And textile workers in China who come into contact with these fibers have been found to have an increased risk of miscarriage.
Clothing made from synthetics continues to cause problems after the last button has been sewn on. When they are washed, microplastic particles enter the environment. Researchers have found that washing five kilograms of clothing can release six million microfibers into the wastewater; washing a single synthetic fleece jacket can set free 250,000 such particles. Little is known about the effects of these microplastics on human health. But it is particularly worrying that microplastics attract other contaminants like a magnet. These contaminants includes persistent organic compounds and other long-lived toxins that are especially harmful to health. These compounds attach themselves to the microplastics and enter the food chain. They have already been detected in salt, fish, mussels and even in human faeces. Sewage treatment plants and washing machines are not yet able to filter out the offending microfibers.
Consumers must bear part of the responsibility. Even though the clothing could still be worn, 64 percent lands in the garbage. In the European Union, 80 percent ends up either in a waste incinerator or in a landfill. Of the remaining garments, just 10 to 12 percent are resold locally. The remainder is exported to developing countries, where it undercuts local clothing producers and destroys their markets. Textiles that end up in the sea float at a greater depth than other plastic products and can interfere with marine life there.
One cause of these problems is the “fast fashion” industry. Companies flood the market with huge amounts of cheaply produced clothing. In the USA in the last 20 years, the volume of clothing that is thrown away each year has doubled from 7 to 14 million tonnes. That means the fast fashion industry contributes in a big way both to environmental pollution and to health risks. Outdoor culture, which demands clothing that is as functional as possible, also fuels the production of synthetic fibers.
The recycling of clothing is gathering pace, but it makes little difference to the underlying problem. The global consumption of recycled polyester rose by 58 percent between 2015 and 2016. But to make large-scale recycling feasible, different types of fibers should not be mixed. Separating blended fibers during recycling is very costly. Along with the need to produce fabrics that are suitable for recycling, a comprehensive system to return used clothing is needed — one that does not yet exist in many countries. But this still remains a superficial, temporary solution. Recycling makes it possible to use synthetic fibers for a longer time, but their quality deteriorates with each cycle, and in the end they still land in the trash.
A more sustainable mode of consumption is unavoidable if we really want to reduce the environmental and health risks. Buying clothing in second-hand shops and swapping garments with other people are good ways to slow down the production of new clothes. Producers cannot currently meet the demand for clothing using fibers from sustainable sources, such as organically grown cotton. Organically based textiles exist, and new approaches are being developed to transform natural materials, such as crustacean shells, trees, hemp, nettles and flax — ideally from local sources — into fibers suitable for making textiles. But these processes too must be checked for their effects on the environment, health and society. Potential pitfalls that must be avoided include monocultures, the use of chemicals that are harmful to the health or the environment, and unsustainable forestry practices.