It is time to pack up the winter clothing after Tuen Ng, the Dragon Boat Festival, as the weather warms up again. But before storing winter items in the wardrobe, they have to be cleaned. The cleaning, however, results in pollution, as wastewater from contains microfibres coming off the clothing that cannot be removed completely by the present wastewater treatment processes.
Microfibres are miniscule man-made plastic fibres, with a diameter one-fifth that of a single hair. The use of microfibres allows garments to become soft, more elastic, retain warmth, and keep out wind and water. Conventional wastewater treatment cannot deal with these fine microfibres. Studies have estimated that about 1.7g of microfibres will fall off from a jacket containing such materials during cleaning, and about 10% to 40% of the microfibres will remain in the treated wastewater and be discharged into the sea or water bodies. In a city with a population of 100,000, there might be 170kg to 441kg of microfibres from washing each day.
Once microfibres enter into rivers or the sea, they are easily taken up by aquatic animals such as fish, shrimps, crabs, oysters and shellfish. The synthetic materials cannot be digested and will be accumulated in the bodies of the animals, inhibiting their digestive systems, and perhaps eventually leading to starvation. In addition, toxic substances may become attached to the surfaces of the microfibres and enter the animals’ bodies. Larger organisms at higher levels of the food chain – such as whales, dolphins and humans, which consume these animals will absorb the microfibres and toxic substances at the same time.
We cannot avoid doing laundry. Yet we can choose more environmentally friendly clothing such as natural materials that can be degraded. Artificial fibres such as polyester, polyamide and polypropylene should be avoided. Also, clothing tagged with “soft fabrics” and “quick-drying fabrics” is also likely to be made from microfibres – so beware!