The Inequalities Of Laundry: U Of T Research Reveals Overlooked Source Of Microplastic Pollution

A new study finds that handwashing polyester in mineral-rich water releases more microplastic fibres, exposing those without access to washing machines to environmental risks

Researchers at U of T Engineering have observed that handwashing synthetic fabrics in water with higher total dissolved solids (TDS) leads to more microplastic fibres (MPF) being released, creating implications for billions of people without access to soft water or washing machines.

The study, described in a paper published in Scientific Reports, looked at polyester fabrics and how they fared when handwashed in various types of water.

Some fabrics were covered in a silicone-based coating meant to reduce the MPF release, but the researchers found that the efficacy of this coating varied under different conditions.

According to a report from the Changing Markets Foundation, synthetic fibres — such as polyester, nylon and acrylic, mainly used in fast fashion — account for about two-thirds (69%) of textile production and are projected to rise to nearly three-quarters (73%) by 2030.

When synthetic fabrics are laundered, the friction caused by the laundering process leads to MPFs being released into waterways.

A significant contributor to global plastic pollution, microplastics are difficult to fully remove from water. While the impacts to human health remain unclear, microplastics are a risk to marine life, as they can block digestive tracks and cause injury when swallowed.

Professor Kevin Golovin’s (MIE) DREAM lab had previously created a silicone-based coating to reduce friction in the laundering process and prevent the fibres from breaking off, but the coating was only tested with machine laundering fabrics.

When Amanuel Goliad (MSE 2T3, MASc student), lead researcher and author on the paper, started asking how the coating fared in hand-washed cycles, he realized there was a research gap and decided to address it.

Goliad, whose family is from Ethiopia, grew up knowing about handwashing and understanding how prevalent it is.

“Nearly two-thirds of the world does not have access to a washing machine,” says Goliad.

“Most people around the globe hand wash, yet nearly all the microfibre research focuses on machine laundering in high-resource settings.”

To conduct his study, Goliad adapted a bamboo washboard-based method from another research paper, noting that so little research is done on hand washing that it was difficult to even find a standardized method to pull from.

He then washed green and black polyester fabrics, both coated and uncoated, using deionized, tap and Lake Ontario water. After washing, he filtered the wash water to count and analyze the MPFs.

Under the microscope, Goliad found that not only were there significant amounts of MPFs being released but also that the coating didn’t always prevent as much MPF release as it had in previous research using washing machines.

When looking at the coated green polyester fabric, the coating reduced fibre shedding by about 92% in deionized water but only 37% in Lake Ontario water, illustrating how its efficacy declines as TDS increases.

“The biggest impact in the efficacy of the coating comes from the type of wash water,” says Golovin.

“Most people that hand wash clothing use whatever body of water is locally available; it could be a river, an ocean, a lake. There are more total dissolved solids within them, and that affects the release of these microfibres more than people realize.”

At the same time, most research is being conducted in labs using deionized water, which has a TDS of 0, meaning that studies don’t reflect the real washing conditions of much of the world.

“There are additional implications for communities that don’t have access to laundry machines,” says Golovin.

“They’re the ones being exposed to more microfibres, but the policies and standards don’t reflect this. A potential action item resulting from this research and hopefully follow-up research is that those communities might need better water filtration systems than what global policy is stipulating, because they’re exposed to more MPFs.”

Another surprising find in the study were the actual lengths of the fibres.

“Higher TDS levels resulted in shorter fibre lengths,” says Goliad.

“That’s important because shorter fibres are harder to filter out in filtration systems; they spread more quickly and they’re more easily ingested by aquatic life.”

Golovin says the discovery of shorter fibres also have implications for how they’re currently measured.

“We have a new hypothesis that the dissolved minerals in harder water may be breaking the fibres into smaller pieces,” says Golovin.

“This affects how we measure microfibre release. If they’re being chopped into smaller fragments, simply counting fibres does not give an accurate picture.”

Golovin is advocating for measuring the total mass of the fibres released over just the count. He also notes his lab is researching fabric coating that can better withstand being hand washed in water with higher TDS.

“I hope this work highlights the environmental impact of hand washing and the need for more inclusive research,” says Goliad.