Wool has long been lauded for its performance characteristics. But the natural fiber’s ability to fully biodegrade adds another impressive credential as microfiber pollution threatens marine ecosystems.

At nearly two-thirds of global market share, synthetic fibers such as polyester and nylon form the backbone of today’s textiles industry. Yet unlike their natural predecessors, these relatively novel fibers do not biodegrade and have become a leading cause of marine microfiber pollution.

The release of such fibers that lack the ability to biodegrade not only contaminates natural and marine ecosystems and burdens landfills, but it also enters the food chain and poses health risks to animals and humans alike.

Wool is a natural fiber that stands apart.

Tests confirm wool is 100% biodegradable

A “biodegradable” label confirms that a material has specific properties and a chemical structure that enables it to be decomposed by the action of living organisms, such as fungi and bacteria. Wool is composed of the natural protein keratin, which is similar to the protein that makes up human hair. When disposed of, it naturally biodegrades in soil in three to four months — depending on the soil, climate, and wool characteristics.

While research shows that dyeing may cause an increase in the initial resistance of wool fabric to biodegradation, this is typically a short-term effect that doesn’t inhibit decomposition beyond eight weeks.

Wool can also be compostable. To earn this label, the material must be made of organic material that breaks down in less than 12 weeks and is a positive contributor to soil health. As natural wool composts, it releases valuable nutrients back into the earth such as nitrogen, sulfur and carbon, which are used by growing plants.

The key difference between biodegradability and compostability is the timeframe. All materials biodegrade eventually. Some materials — such as synthetic fibers — take hundreds of years to biodegrade, while others — like wool — only take a few months. All compostable material is biodegradable, but not all biodegradable material is compostable.

Addressing marine microfiber pollution

With washing and wearing, all fibers miniaturize and shed — wool included. This fact becomes problematic when these fibers do not naturally decompose, but instead accumulate in the environment. Given the global prevalence of synthetics and their resistance to biodegradation, research supports that they now contribute significantly to harmful marine microfiber pollution.

Microfiber pollution refers to the contamination of the environment with fibers from synthetic textiles. According to the European Environment Agency, approximately 16-35% of global microplastics released to oceans are from synthetic textile microfibers.

In contrast, research shows that wool biodegrades readily in a marine environment and does not contribute to long-term microfiber pollution. This holds for both untreated wool and machine-washable wool. In fact, AgResearch has found that wool treated with a superwash finish biodegrades more rapidly than untreated wool. This is because the treatment process removes some of the fiber’s cuticle, rendering it more susceptible to microbial degradation.

In short, new research on the hazards of marine microfiber pollution and the benefits of biodegradability continues to confirm wool’s status as an ideal fiber choice for both people and the planet.

Photo: IWTO