What are they?
Microplastics are small particles of plastic that are 5 mm in size or less, are found in marine and aquatic environments, and tend to come from different sources in different forms. Waste water treatment facilities release microbeads from their cleaning products, and microbeads within beauty and care products end up in aquatic systems as well. Another type of microplastic is pieces breaking off from single use plastic items like bags, straws, and cups. Microplastics also come from textiles and clothing in the form of microfibers, typically due to washing machine waste waters. Because these particles are so small they can be found all over the world in oceans, on mountains (in the snow) and in rivers.
Microplastics in Freshwater Systems
Although microplastics have been studied since the 1970s, data on freshwater systems is limited because it is a more recent field of research. Scientists believed that rivers acted as pathways for microplastics to travel from one area to the next, but studies show that concentrations of microplastics are consistently being found in sediments, fish, and bodies of water. In a study done on microplastic presence in the Snake River and Palisades Reservoir, over 70% of the samples had microplastics in them, and only 1,750 ml of water were taken for each sample. The researcher acknowledged that microplastics could have been lost during transferring, so numbers could be underestimated, but they still found the data to be alarming. Most of the plastics found were microfibers, which is typical for microplastic research in freshwater systems.