Washing clothes on a delicate setting is the worst of all cycles for the environment as it causes hundreds of thousands of extra microfibres to be released into the water system, scientists have warned.
Although regular washing machine cycles cause clothes to be pushed together more, they use less water than gentler cycles, according to research by Newcastle University.
It is the volume of water used – as opposed to the spinning action – which causes the most tiny particles of plastic to be shed, researchers found.
Because these fibres are so small, they drain out of the back of the washing machine and can ultimately, enter the marine environment where they can be ingested by small animals and end up in our food chain.
Millions of plastic microfibres are shed every time we wash clothes that contain materials such as nylon, polyester and acrylic.
PhD student Max Kelly measured the release of microfibres from polyester clothes from a range of different cycles, temperatures and water volumes.
Counting the fibres released, his team found the higher the volume of water the more fibres released, regardless of the speed and abrasive forces of the washing machine.
Using a hi-tech camera, they counted 1.4 million fibres from a delicate wash of a polyester garment, 800,000 when a normal cotton wash was used and 600,000 from a cold express programme.
Mr Kelly said: “Counter-intuitively, we discovered that ‘delicate’ cycles release more plastic microfibres into the water, and then the environment, than standard cycles.Previous research has suggested the speed the drum spins at, the number of times it changes spinning direction during a cycle and the length of pauses in the cycle – all known as the machine agitation – is the most important factor in the amount of microfibre released.
“But we have shown here that even at reduced levels of agitation, microfibre release is still greatest with higher water volume to fabric ratios. This is because the high volume of water used in a delicate cycle, which is supposed to protect sensitive clothing from damage, actually ‘plucks’ away more fibres from the material.”
Consumers should make sure they are using the correct cycle for their laundry and avoid washing half loads so there is not a high volume of water to garments.
Dr Neil Lant, a research fellow from Newcastle University who worked on the project, said: “People thought quite intuitively that a delicate wash cycle would reduce the loss of fibres because the fibres are rubbing against each other less.”
He said garments from natural fibres, such as wool or silk, should still be washed on a delicate programme.
Washing machine manufacturers have developed microfibre filters to catch the mini-pollutants before they are released into the water system, while the textile industry has worked on reducing fibre shedding.
Marine microbiologist Professor Grant Burgess said it was thought the microfibres can clog the digestive systems of the tiny animals that ingest them.
He added: “Some of these fibres can attract pollutants and toxic chemicals which stick on to the fibres. They can act as concentrators of other toxic pollutants and act as a carrier of these nasty chemicals.”
The findings were published in the journal Environmental Science and Technology.
Additional reporting by Press Association