Using the delicate cycle on your washing machine could be making the microplastic pollution problem worse rather than better, if a study from Newcastle University in the UK is to be believed. By James Teo.

Newcastle, October 1 2019. The best way to tease out most plastic microfibres (yes, those bit of shredded plastic that get into the food chain right down at plankton level) out of your dirty clothes and into the environment is to wash them on a delicate washing cycle, then tumble dry them.

The research team, led by PhD student Max Kelly, said that although the idea of a gentle wash flushing out more plastic pollution seemed wrong, his data showed that was in fact the case. The team sampled the results from wash cycles using differences in water volume, spin speed, temperature and time washed. They then employed DigiEye, a digital imaging system, to calculate the amount of microfibres released.

"Previous research suggested the speed the (washing machine) drum spins at, the number of times it changes spinning direction during a cycle and the length of pauses in the cycle - known as the machine agitation - as the most important factors in the amount of microfibre released," he said. But through the use of a sophisticated machine that closely analysed the suspended plastic fibres in the outgoing water, he discovered that even at reduced levels of agitation, microfibre release is still greatest with higher water-volume-to-fabric ratios. Which is exactly what most domestic machines use during gentle wash programs.

"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," he explained. In fact the results showed that an average of 800,000 more plastic microfibres were released in delicate cycles compared to a standard wash.

This is especially the case when so called delicates, made of synthetic fabrics such as polyester and nylon are washed. These textiles are made up from strands of oil-based plastics, which under duress such as being tumbled in a washing drum, shed tiny plastic fibres when they crease and flex. These are then washed out of the fabric by rinse water which ends up in our drains, and ultimately in the ocean.

After exhaustive analysis of the results that compared different wash cycles, researchers from the UK found that water volume, rather than the level of agitation of the clothing by the machine's spinning, was the key factor in releasing microfibres. To make matters worse, popping the gently washed clothes into the tumble dryer can compound the micro-plastic problem by flushing out more than three times the amount of fibres that a standard was cycle might produce.

Research is being conducted on new filter systems that help to cut down on pollution from domestic machines, with several new filtering solutions found to retain some or most of suspended microplastic in rinse water. This also showed that the use of physical filters was most dramatic the first time the new fabric was washed. The amount of fibres picked up went down over successive washes, but then stayed the same from ten washes onwards. But this adds to the cost of the machines – something that might stop well-intentioned buyers opting for the better-filtered option.

“It is also necessary to further investigate … an alternative that is technologically, economically feasible as well as environmentally beneficial. Although the filters may retain microplastic fibres it may be necessary to design filtering solutions that are sufficiently user-friendly so that the filters are not by-passed by the user, and that there are good options for emptying or replacing the filters,” said the researchers.

Kelly said that the best approach – apart from washing machine makers building in better filters – was to save up all your clothes for one big wash. That way, the amount of water coming into contact with the fibres would be minimal, resulting in less microfibre flushing. Then, always hang the newly-washed laundry out to dry, no matter what they are made of.

Of course, the issue is not really with the washing machines and the cycle you choose, but with the fabrics. Choose natural fibres and your wash will be much less likely to harbour microplastics refuse. No excuse!