February 11, 2019 A Fiber for Life
The keratin fiber, wool, has evolved along with the rest of life on Planet Earth. As part of the natural carbon cycle, wool grows on sheep and biodegrades readily – making wool fiber a naturally sustainable choice.
Nature is the original circular economy. Carbon, oxygen, nitrogen and other molecules continually shift from one form of life to the next in a cycle that has operated since life on Earth began. Biodegradation – micro-organisms in soil or water breaking down matter so it can be recreated – is the key to this process.
Keratins like wool readily biodegrade, particularly in warm, damp conditions and in the presence of oxygen – a healthy soil or compost, for example. Initially, fungi colonize and weaken the outside of the fiber. Then, bacteria begin digesting it. When wool is kept dry or there is an absence of oxygen, however, it is extremely durable. Archaeologists have found preserved wool samples dating back thousands of years.
Wool and microplastics
Ready biodegradability is a key difference between wool and the oil-based synthetic fibers. In ideal conditions, wool products are almost completely degraded after six months in the ground and can even function as an effective soil conditioner and fertilizer.
Synthetic fibers do not readily biodegrade. Their chemical structures were developed during the past 50 years, and nature has not yet evolved a ready means to recycle them. Instead, they progressively miniaturize and then bio-accumulate. These tiny plastic particles are now causing great concern to the medical community, environmentalists, and conscious consumers around the world.
While more research is required, independent sources provide some confidence that fibers shed during the washing and wearing of wool clothing are unlikely to contribute to persistent pollution. Wool has been shown to biodegrade in marine environments, in laboratory and on-site testing. Experiments in New Zealand showed surface damage to wool fibers after 21 days incubation in sea water, and the presence of wool-degrading bacteria was confirmed. In addition, early data from research in seabirds shows that when ingested, the proportion of natural microfibers in the digestive tract of birds declines from esophagus to stomach to intestine, indicating that they are likely being digested naturally.
Sustainability at the IWTO
Nonetheless, there is much more to be done. The International Wool Textile Organisation (IWTO), whose worldwide membership encompasses the wool textile pipeline from sheep to shop, is contributing to the science of sustainability. Current research includes a study of the biodegradation of wool, including the number and fate of wool microfibers formed during garment care. This research will ultimately help inform consumers about how their product choices can be part of a sustainable world.