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Machine-washable wool biodegrades faster


New research from The Woolmark Company has found that merino wool does not contribute to the issue of pollution in the oceans of the world.

The scientific study, Microfibre Pollution and the Marine Biodegradation of Wool, has found that untreated and machine-washable wool are both readily biodegrade in marine environments, while synthetic fibres do not. The study also found that machine-washable wool 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.

Previous estimates suggest as much as 20% to 35% of all primary source microplastics in the marine environment are from the use of synthetic clothing, The Woolmark Company said, and a single polyester fleece garment can produce more than 1,900 microfibres per wash.

In this latest study, researchers compared the biodegradability of the two types of merino wool in sea water to the biodegradability of viscose, 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, paper pulp.

Scientists found untreated wool biodegraded at 20.3% of the rate of paper pulp while the machine-washable wool biodegraded more than three times as quickly, at a rate of 67.3%, the fastest of all fabrics.

At the tail-end was nylon, biodegrading at a rate of just 0.8% of paper pulp, followed by polypropylene and polyester.

Managing director, Stuart McCullough, said on announcing the results of the study: “Wool has long been heralded the original eco fibre, but concerns had been raised about the machine-washable finish applied to wool and whether it added to the microplastic problem, so we wanted to clarify that issue. It’s important to consider how well-intentioned consumers can make purchasing decisions that help look after the health of the environment. Choosing natural fibres, such as merino wool is an important place to start.”