Your clean clothes have a dirty secret — every time you do the laundry, the fabrics shed tiny fibres into the water, contributing to the hundreds of tonnes of microfibres released into our rivers and oceans every year."Microfibres are tiny pieces of plastic that can be harmful to fish and other aquatic life. Once these pieces are in the environment, they carry toxic chemicals up the food chain — first they get ingested by zooplankton, which in turn get eaten by fish and so forth, impacting progressively larger animals," said Richard Stewart, Chair of Metro Vancouver's Liquid Waste Committee. "Thankfully, we're learning that small acts can have positive impacts, like washing your laundry in cold water. Warm and hot water causes clothes to break down more quickly than cold water, increasing the shedding of microfibres."Microfibres are pieces of fibre — less than 5mm in size and thinner than a human hair — that are shed from fabrics when they are washed. Many microfibres are made of synthetic materials and are basically tiny pieces of plastic, but natural materials (like cotton) also shed microfibres when washed. While all fabrics, whether natural or synthetic, shed fibres in the wash, synthetic microfibres are one of the largest sources of microplastics pollution in the world's oceans."The science around microfibres is still emerging — Metro Vancouver is collaborating with Ocean Wise, UBC and others to better understand how this type of pollution affects ecosystems and what may be done to address it," said Sav Dhaliwal, Chair of the Metro Vancouver Board of Directors. "Currently, pilot testing has shown that washing in cold on shorter cycles reduces microfibre shedding by up to 50 per cent."Everyone can do their part to reduce this pollution at the source. Many other factors also determine how much fabrics shed, including how they are made, treated and washed. New clothes generally shed the most microfibres the first few times they are washed, so wearing your clothes more often between washes or buying second-hand items can also help.Metro Vancouver is part of the Microfiber Partnership, a research initiative that brings together researchers, the apparel industry and governments, and is supporting the development of standardized methods to quantify and track microfibres in wastewater.Visit switchtocold.ca to learn more about the issue and what you can do to help.