A study locates denim microfibers in Arctic marine sediments. “An indicator of the impact of humans on the environment.”

A stock image of a washing machine.

Washing denim clothes releases microfibers into sewage that, according to a new study by Canadian experts, have been detected even in remote areas arctic marine sediments, says an investigation published this Wednesday in the scientific journal Environmental Science & Technology Letters.

A team led by Samantha Athey from the University of Toronto (Canada) investigated whether the denim clothes it was an important source of anthropogenic cellulose microfibers for the aquatic environment. The team noted that they do not know the effects, if any, that denim microfibers have on aquatic life, but found that finding them in the Arctic is “a powerful indicator of human impact in the environment, “says the American Chemical Society.

Denim and non-woven clothing releases microfibers with laundering, and although most are disposed of by sewage treatment plants, some could enter the environment through washing. sewage discharge, also known as effluents.

More than 50,000 microfibers per wash

Denim is made of natural cotton cellulose fibers, processed with synthetic indigo dye and other chemical additives to improve performance and durability. The researchers used a combination of microscopy and spectroscopy to identify and count the microfibers of indigo denim in various samples of water collected in Canada.

The study noted that indigo denim was the 23, 12 and 20% of all microfibers from the sediments of the Great Lakes, shallow suburban lakes near Toronto, and the Canadian Arctic Archipelago, respectively.

Based on the levels of microfibers found in the wastewater effluent, the researchers estimated that the wastewater treatment plants analyzed in the study some 1 billion microfibers were unloaded of indigo denim a day.

With laundering experiments, the team saw that a single pair of used jeans could release around 50,000 microfibers per wash cycle.