Most "fleece" is just extruded plastic filament and its use in clothing is, according to clothing company Patagonia, a serious source of pollution. Washing them results in microplastic soup, which then heads into the sewers and hence to the seas.
During laundering, a single fleece jacket sheds as many as 250,000 synthetic fibers—significantly more than the 1,900 fibers Browne first recorded. Based on an estimate of consumers across the world laundering 100,000 Patagonia jackets each year, the amount of fibers being released into public waterways is equivalent to the amount of plastic in up to 11,900 grocery bags. … Add to the list of concerns unique to the outdoor industry: chemical additives in performance apparel (think waterproof-breathable duds) that enter the water along with the fibers.
Patagonia is "researching new yarn and fabric constructions" as a result. In the meantime, soup's up!
Here's the original paper.
Synthetic textiles can shed numerous microfibers during conventional washing, but evaluating environmental consequences as well as source-control strategies requires understanding mass releases. Polyester apparel accounts for a large proportion of the polyester market, and synthetic jackets represent the broadest range in apparel construction, allowing for potential changes in manufacturing as a mitigation measure to reduce microfiber release during laundering. Here, detergent-free washing experiments were conducted and replicated in both front- and top-load conventional home machines for five new and mechanically aged jackets or sweaters: four from one name-brand clothing manufacturer (three majority polyester fleece, and one nylon shell with nonwoven polyester insulation) and one off-brand (100% polyester fleece). Wash water was filtered to recover two size fractions (>333 μm and between 20 and 333 μm); filters were then imaged, and microfiber masses were calculated. Across all treatments, the recovered microfiber mass per garment ranged from approximately 0 to 2 g, or exceeding 0.3% of the unwashed garment mass. Microfiber masses from top-load machines were approximately 7 times those from front-load machines; garments mechanically aged via a 24 h continuous wash had increased mass release under the same wash protocol as new garments. When published wastewater treatment plant influent characterization and microfiber removal studies are considered, washing synthetic jackets or sweaters as per this study would account for most microfibers entering the environment.
