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Wool does not contribute to microplastic pollution

As much as 35 per cent of microplastics in the marine environment are fibres from synthetic clothing, an amount that continues to increase. But by contrast, science has shown that wool readily biodegrades in both land and marine environments, offering a less impactful solution and not contributing to microplastic pollution.

Against the deep blue of the north Pacific Ocean, somewhere off the coast of California, a 700,000sq kilometre gyre of marine debris particles sits ominously. Accumulated over the course of decades by the natural currents, the Great Pacific garbage patch, as the mass of plastic is described, poses a significant threat to the prosperity of marine life, including the flocks of seabirds that travel through the area, as they ingest hundreds of pieces of plastic, the result of photo-degradation caused by the fibre’s inability to biodegrade like organic debris, and subsequently splits into smaller and smaller particles, right through to the molecular level, where they enter the food chain.

What is microplastic pollution?

Microplastic particles, including microfibres from synthetic clothing and textiles, are now ubiquitous in aquatic and land-based ecosystems across the world. In fact, it is estimated that 0.6-1.7 million tons of microfibres are released into the ocean every year, with new research by the University of Manchester, recently published in Nature Geoscience, finding the number of microplastic pieces in the world’s waterways is vastly greater than originally thought. Without active intervention, the abundance of these <5mm in diameter particles is set to increase as consumption of plastics and man-made fibres in clothing expands to meet demand from a rising world population and increasing regional incomes.

“An effective strategy for consumers to reduce their contribution to microfibre pollution would be to choose garments made from natural fibres.”

Dr Beverley Henry

Microfibres can enter the environment through sources such as fibres shed from synthetic apparel during use and washing, or through other secondary sources, predominantly degradation and fragmentation of larger pieces of synthetic textile waste. While the full extent of the negative impacts of microplastic pollution on aquatic habitats and organisms is yet to be fully understood, the current research suggests physical, chemical and biological impacts are felt throughout the food chain including leaching of toxic chemicals and eventual starvation of host organisms.

Furthermore, fibre-shaped microplastics appear to be of greater environmental consequence than more regular shaped particles due to a tendency for entanglement in the digestive tract that can lead to blockages and a higher chance of compromised growth, reproduction or even starvation. Chemical impacts may also be enhanced since the larger surface area of fibres potentially allows greater sorption of harmful compounds and a higher retention in the gut allows more time for leakage of plastic additives. The full extent of the impact on human health is yet to be known, yet it is largely acknowledged that microplastics may enter the human body through the food chain and drinking water.

“Wool readily biodegrades and consequently doesn’t amass in the environment.”

Angus Ireland

Wool does not cause microplastic pollution

Ground-breaking new research from The Woolmark Company has found that Merino wool does not contribute to the issue of microplastics in our oceans.

The scientific study - titled Microfibre Pollution and the Marine Biodegradation of Wool - has found that both untreated and machine washable wool readily biodegrade in marine environments, while synthetic fibres do not. The study also found the machine washable wool actually biodegrades at a faster rate than untreated wool fabrics and there was no evidence the treated wool’s polyamide resin coating added to microplastic pollution.

In this latest study researchers compared the biodegradability of the two types of Merino wool in sea water to the biodegradability of viscose rayon, polyester, nylon and polypropylene. Residues were examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. All fabrics were washed repeatedly before testing to simulate a partial garment lifetime. The rate of biodegradation was then compared to that of a substance known to biodegrade readily, kraft paper pulp.

Scientists found untreated wool biodegraded at 20.3 per cent the rate of the pulp and the machine-washable wool biodegraded more than three times as quickly, at a rate of 67.3 per cent – the fastest of all fabrics.

At the tail-end was Nylon, biodegrading at a rate of just 0.8 percent, followed by polypropylene and polyester.

Another review into microplastic pollution from textiles recommends an increased use of natural non-synthetic materials, such as wool, in global textile markets, because wool biodegrades in marine as well as land environments and therefore does not cause microplastic pollution. The review, published by Consumption Research Norway (SIFO), was conducted by Adjunct Associate Professor Beverley Henry of the Queensland University of Technology and researchers from SIFO, with support from Australian Wool Innovation (AWI, the owner of The Woolmark Company) and the Cotton Research and Development Corporation.

“An effective strategy for consumers to reduce their contribution to microfibre pollution would be to choose garments made from natural fibres which are biodegradable and do not contribute to the build-up of microplastics in the environment,” Dr Henry said of the review. “The positive attributes of wool in terms of durability, recyclability and low impact care (less frequent washing, at lower temperatures with less detergent/conditioner) are consistent with strategies to minimise shedding of microfibres to the environment.”

“The positive attributes of wool in terms of durability, recyclability and low impact care are consistent with strategies to minimise shedding of microfibres to the environment.”

Dr Beverley Henry

The man-made trash vortex is an imposing presence, one documented in the Craig Leeson-directed documentary Plastic Oceans in which teams of scientists and marine biologists explore the dire effects of the toxic pollutant and point to its long-term ramifications not only on the natural environment but human life, too. Through a responsible choice of what we wear, and how we care, we can ultimately contribute to the long-term health of the planet.