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How Plastics Breakdown into Microplastics
Microplastics are being found in oceans and waterways all over the world. This resource explains what microplastics are and how they are generated.
What are Microplastics?
Microplastics are small plastic particulates that measure less than 5 mm in size. Microplastics are not visible in water and will either float or sink depending on what they are made of.
Microplastics like polypropylene are lighter than seawater and will float and disperse widely across waterways. Microplastics like acrylic are denser than seawater and will accumulate in the deepest parts of the ocean.
99% of plastics in the ocean are thought to be microplastics.
Microplastics that float will eventually accumulate together in gyres which are large oceanic currents. Microplastics that sink are mistaken for food by sea life. The hadal zone (deepest part of the ocean) could be one of the largest microplastic sinks on Earth. Microfibres are also a type of microplastic. They include small fibers that enter the water from washing clothing made of synthetic materials, like polyester and nylon.
Sources of Microplastics
- Synthetic textiles
- Exterior plastic materials (siding, coating, paint, furniture, etc.)
- Wet wipes
- Tea bags
- Cigarette butts
- Laundry/ dishwasher pods
- Tire weathering
- Household plastic waste
How Microplastics are Generated
- 64% of fabric is made from plastics, including polyester, nylon, acrylic and polyamide.
- Every time synthetic textiles are washed, 700,000 tiny pieces of plastic fabrics break off, and up to 40% of them enter rivers, lakes and oceans.
- Sewage and wastewater treatment plants are primarily designed to treat waste, and do not have the capability to filter out most microplastics before being released into the environment.
Plastic waste in water systems
When larger pieces of plastic waste are disposed of in the environment they get weathered and degrade. These larger pieces of plastic break down into smaller and smaller pieces and are eventually reduced to microplastic particles.
For example, as this single-use water bottle is weathered and degraded, the plastic will break down into small pieces. These small pieces are consumed by fish and other marine life, which eventually impacts the entire food chain.
Research on microplastic pollution has primarily focused on the ocean. However, recent research has shown microplastics are an issue in both freshwater and terrestrial environments.
- Boucher, J. and Friot D. (2017). Primary Microplastics in the Oceans: A Global Evaluation of Sources. Gland, Switzerland: IUCN. 43pp. Accessed from: https://portals.iucn.org/library/sites/library/files/documents/2017-002-En.pdf
- Wieczorek AM, Morrison L, Croot PL, Allcock AL, MacLoughlin E, Savard O, Brownlow H and Doyle TK (2018) Frequency of Microplastics in Mesopelagic Fishes from the Northwest Atlantic. Front. Mar. Sci. 5:39. doi: 10.3389/fmars.2018.00039
- National Oceanic and Atmospheric Administration: Marine Debris Division. What are microplastics? Microfibers?. Website: https://marinedebris.noaa.gov/fact-sheets/microplastic-marine-debris-fact-sheet