A known source of microplastics entering the sea and freshwater systems is through shedding from synthetic fabrics in the process of washing clothes and laundering other products. This is also generating concern about the microplastics being captured in global seafood products.
A substantial body of research has established how wool biodegrades on land, but far less was understood about its behaviour in the aquatic environment until recently. As the International Wool Textile Organisation publicised in March 2020, our scientists conducted a study to compare fabrics for how much they biodegraded in water. The fabrics were washed repeatedly before testing to simulate a partial garment lifetime.
The study found that both untreated and machine-washable wool readily broke down in the water, as did cellulose-based viscose rayon. In contrast, synthetic fibres that were tested – polyester, nylon and polypropylene – showed little or no biodegradation in an aquatic environment. The treatment that makes wool machine-washable, preventing felting by applying a thin film to the fibre surfaces, actually caused the wool to biodegrade more rapidly than untreated wool.
Work to further establish the environmental credentials of wool is continuing at AgResearch with further funding from Australian Wool Innovation.