The American Chemical Society reports that blue jeans, a popular wardrobe choice during the COVID-19 pandemic due to an increase in telecommuting, creates a unique type of environmental pollution. This denim is processed with synthetic indigo dye and other chemical additives. Researchers in Canada have detected indigo denim microfibers in wastewater effluent, lakes and even remote Arctic marine sediment, as noted in Environmental Science & Technology Letters.

Washing denim releases microfibers that are mostly removed by wastewater treatment plants, yet some still enter the environment through wastewater effluent. The researchers estimate that the wastewater treatment plants in their study discharged about 1 billion indigo denim microfibers per day. In laundering experiments, they found that a single pair of used jeans could release about 50,000 microfibers per wash cycle. The researchers did not study the effects that these microfibers have on aquatic life—perhaps a topic for future inquiry. In the meantime, washing jeans less frequently may reduce denim pollution.