You might not ever have the opportunity to go to the Arctic, but there’s a chance your jeans might pay it a visit someday.
It’s well known that traces of plastic and other human-made materials have wormed their way into most of Earth’s environments. But it’s less known that a common form of pollution is microfibres from your clothes. Considering denim jeans are one the most popular items of clothes globally — in 2018, more than 4.5 billion pairs of jeans were sold worldwide — researchers recently set out to see how far the presence of denim microfibers has infringed on the natural world.
Reported in the journal Environmental Science & Technology Letters, scientists in Canada discovered that denim microfiber pollution can be found across the suburban lakes of Ontario, the Great Lakes of North America, and even in the Canadian Arctic Archipelago. Although it remains unclear what effect, if any, this might have on marine life, it does clearly highlight how the footprint of humans can be felt in many corners of the planet.
Washing clothes and other fabrics release a huge amount of microfibers into the world’s wastewater, much of which ends up in the planet’s water systems. In regards to blue denim, washing jeans releases natural cotton cellulose fibers, which are topped off with synthetic indigo dye and other chemical additives to improve the material's durability. After looking at samples of wastewater effluent, the researchers worked out that the wastewater treatment plants pump out around 1 billion indigo denim microfibers per day. They also found that putting a single pair of used jeans into the laundry could release about 50,000 microfibers per wash cycle.
The microfibres then embarked on quite a journey. Using a variety of imaging techniques, the team discovered indigo denim made up 23 percent, 12 percent, and 20 percent of all microfibers in sediments from the Great Lakes, shallow suburban lakes near Toronto, and the Canadian Arctic Archipelago, respectively. They even found evidence of a single indigo denim microfibre in the belly of a fish, a rainbow smelt, in the Great Lakes.
Although it’s unclear whether this will have a negative effect on aquatic life, beyond the effects of microfibres, the denim industry is known to make a huge impact on the environment. Not only does it take bucketloads of water to produce a pair of jeans — it requires 1,500 gallons of water to grow the amount of cotton needed to produce one pair — the dyeing and finishing process can also introduce all manner of unpleasant chemicals into water systems. A stark example of this is the Chinese town of Xintang, the so-called "denim capital of the world," where the rivers run blue and the water is riddled with pollution thanks to their intense focus on denim production.