7. Where do microplastics come from?

Differend types of microplastic particles under a microscope. (Photo: Martin Löder)

Microplastics include a wide range of plastics that find their way to the sea. A substantial portion – just how much is still unclear – is created directly in the ocean, when larger pieces of plastic slowly break down. Large amounts of microparticles are also produced directly in the course of plastic manufacturing; what’s more, microparticles can even be released when we wear, wash and dry synthetic textiles like microfleece or other sportswear.

In many cases, this involves minute microfibres that are first suspended in the air, before being carried out to sea by the wind. Washing a single load of laundry with these textiles can release roughly 2,000 fibres, which most wastewater treatment plants can only partially filter out. A study conducted in Norway recently concluded that in developed countries, microparticles can also be produced by wear on car tyres; rain washes them into sewer canals, streams, rivers and ultimately out to sea.

The paint used on ships, which releases small particles of additives like bonding agents and alkyd resins, represents a further source of microparticles. These additives are released as the paint becomes more weathered or is worn off. According to the latest estimates, the percentage of plastic particles from cosmetics (e.g. peelings) is comparatively low – but could also be avoided.