What are microplastics?

There is a lot of plastic waste in the environment and in our waters: beverage bottles, plastic bags, packaging, straws and much more. Less well visible to the naked eye, but nevertheless no less common, are what are known as microplastics. This page provides information about what exactly microplastics are and what quantities occur in Swiss waters.

Definition

Plastic is considered to be a persistent organic pollutant (or POP). It is produced by the polymerisation of monomers based on crude oil, coal, and natural gas. Typical types of plastics are:

• PET (polyethylene terephthalate) e.g. for light bottles
• PP (polypropylene) e.g. for hard food containers or plastic furniture
• PE (polyethylene) e.g. for flexible packaging films
• PVC (polyvinyl chloride) e.g. for buildings and electronic applications
• PS (polystyrene) e.g. for plastic cutlery, coffee cups

There are also two main types of bioplastics:

• “bio-based” or “from renewable resources”, which are produced from renewable raw materials (plants), but are not necessarily biodegradable;
• and “biodegradable” or “compostable”, which are completely degraded into water, carbon dioxide and biomass, but which are not necessarily produced from renewable raw materials. Instead, they may also be produced from crude oil, for example.

Plastic usually contains additional chemicals such as bisphenol A or plasticisers to give the plastic special properties.

In science, plastic particles are usually classified according to their size and origin.

Size

Macroplastics: Plastic particles larger than 200 millimetres
Mesoplastics: Plastic particles between 5 and 200 millimetres
Microplastics: Plastic particles between 5 and 0.0001 millimetres (=100 nanometres)
Nanoplastics: Plastic particles smaller than 100 nanometres

Origin

Primary microplastics: Microplastic particles which are industrially produced in this size for specific applications, for example:

• Pellets as basic material for plastics production
• Granules for cosmetic products like peeling, shampoo and shower gel
• Fibres for clothing
• Active substance carriers in medicine
• Plastic substitutes for sandblasting for machine cleaning

Secondary microplastics: Microplastic particles that are only created by the disintegration or decomposition of larger plastic particles, for example:

• Due to friction and solar radiation in water
• By the washing of synthetic textiles
• By the abrasion of car tyres Strictly speaking, this is micro-rubber. However, it is often classified as microplastic.