Zhou et al. (2020) found that microfibre concentration in an industrial textile facility in China could reach 54,100 microfibres L−1, and even with a removal of 85% in wastewater treatment, release in effluent could still reach 430 billion microfibres per day, with most fibres measuring between 100 and 300 μm.

Sørensen et al. (2021) found that natural and synthetic fibres might release chemicals such as phthalide, phthalimide, and organophosphorus compounds in seawater through UV solar exposition.

For instance, Choi et al. (2022) observed reproductive and cellular toxicity in the mussel Mytilus galloprovincialis due to long-term exposure to PES microfibres, while Kim et al. (2021) found that exposure to both synthetic and natural microfibres caused gut damage and mortality in the brine shrimp Artemia franciscana .

More than 100 million tons of fibres are produced annually, a doubling compared with 20 years ago (Textile Exchange, 2021). Much of this production is used for textiles made of natural or synthetic yarns or mixtures, with the majority being either polyester (PES) (52%) or cotton (30%) (Textile Exchange, 2021).

Some studies have assessed the microfibre release from household wash loads with different used fabric types and ages, focusing mostly on the impact of the weight of wash loads, laundry additives, and wash cycles (Lant et al., 2020; Sudheshna et al., 2022).

For example, it has been estimated that a single domestic wash (5 kg washing load) can release more than 3 million microfibres (De Falco et al., 2019; Özkan and Gündoğdu, 2021).