What is microplastic?
The difference between macro- and microplastic is set to be 5 millimetres. Everything below 5 millimetres can be categorised as microplastic.
Microplastic can come from 2 different sources. Broken plastic products are a considerable factor, but also wear of products releases a lot of microplastic. An example of la arger product that turns into microplastic over time could be a plastic bag that is degraded to smaller and smaller pieces in the course of months or years. If it is on the surface of the sea and thus exposed to UV light from the sun, this process is much faster. If the bag sinks to the bottom of the ocean where the water is dark and stagnant, the degradation process stops and the bag can be there for countless years.(*)
Wear of products such as textile and tires are also examples of microplastic sources. Every time we wash our clothes in the washing machine, millions of fibres are worn of and end up in the sea environment. This kind of microplastic from broken plastic products and wear is called secondary microplastic. Wastewater treatment plants cannot keep back those little particles, and if they are retained in the sludge they end up in the fields.(*) More than 50% of the danish wastewatersludge is brought out to fields as a fertiliser supplement and in this way plastic ends up in our environment.
Today we don’t know how much plastic pollution the individual sources each adds to the environment, and we cannot figure out how best to take action.
Microplastic in lotions, toothpaste and paint
Microplastic can also be directly produced. A good example is microplastic that is blended into toothpaste, scrub lotions and paint. Microscopic beads of microplastic is blended into these products to have a scrubbing and grinding effect, most often polyethylen (PE) or polypropylen (PP). There can be up to 350.000 pieces in one single lotion. This form of microplastic is called primary microplastic.
The app 'Beat The Microbead'
Plastic Change works to completely phase out primary microplastic that is blended into products. Read more about how to scan your way around products with added microplastic using the app: 'Beat The Microbead'.
Right now the latest knowledge produced in Denmark is a report that Cowi has made for the environmental protection agency about sources and amounts of microplastic in Denmark.
The report is the first suggestion of an overview of microplastic sources in Denmark. Many assumptions underlie the conclusions of the report, among other things the fact that the sources of microplastic come from tires especially. The report is a first important study, however a desk job, and we still remain to find out whether those numbers in the report can be confirmed in nature. Are tires and road stripes, textile laundry and more the number one causes?
This is something we will learn a lot more about in the Danish project Plastfree Roskilde Fjord. (The project is briefly described here). With the project in Roskilde fjord, we get completely new knowledge about the extent of microplastic in beach sand, the column of water, lugworms and clams, and we research in absorption and transport in the food chain as well as analyse all sources. By analysing the content of microplastic locally in waste water treatment plans in Roskilde fjord, before and after purification, we get important knowledge about whether the waste water treatment plants retain the microplastic that can be found in beauty products and laundry. International studies show that waste water treatment plants only partly retain the microplastic, but we still need to understand where it ends up. That is why we also analyse the sludge from the waste water treatment plants. At least 50% of the waste water sludge in Denmark is dispersed as fertiliser in Danish fields. In this way, microplastic potentially ends up in the fields and can be washed out to lakes, streams and thus the ocean.