Ecotoxicological and Humantoxicological effects of microplastics

Photos of dead sea birds and fish with a belly full of plastic waste have been widely seen. The dangers of large plastic particles in the environment are obvious. If plastic particles are confused with food and are eaten by animals, they can enter the digestive tract and cause abrasions, ulcers and constipation, and eventually lead to starvation and death.

However, small plastic particles in Swiss lakes and rivers may also pose a risk to aquatic organisms. Little is known about this as yet. However, it can be assumed that the effects of microplastics are very similar in smaller animals that confuse microplastics with food. Microplastics have already been detected in the stomach and intestines as well as in the liver of larger animals such as fish.

In addition to microplastics themselves, toxic ingredients such as plasticisers or chemicals absorbed by the plastic particles can also cause damage. Little is yet known about the effects of these additives, especially when they occur in combination. Like other surfaces in waters, the particles are also covered by microorganisms such as bacteria. As a result, a biofilm is formed. There are the first signs that harmful microorganisms can be concentrated on plastics.

In contrast to humans or non-aquatic animals, aquatic life forms are more exposed to polluted water. They live in the water 24 hours a day. In addition, they absorb the pollutants not only during food intake, but also during respiration via the gills and body surface.

Microplastics can essentially cause three potential problems in humans:

  • Physical damage in the human body by the particles themselves
  • Chemical damage caused by additives such as plasticisers, endocrine disrupters and carcinogens
  • Damage caused by microorganisms adhering to the particles

There are currently hardly any studies available in Switzerland. According to the World Health Organisation (WHO), the physical risk is low, since microplastics larger than 0.15 mm are unlikely to be absorbed by the human body. It can hardly pass through the intestinal mucosa and is excreted quite quickly. The intake of smaller particles is likely to be limited. However, very small microplastic particles and nanoplastic particles are likely to be absorbed by the body. Nonetheless, the available data is very limited.
(Source: WHO)

The WHO also classifies the risk posed by chemical additives or microorganisms as very low, as the amount of substances absorbed into the body is very small. The risk from microorganisms in the water pipes or from contaminants when filling the drinking water is much greater. It is therefore much more effective to start out with the latter.
(Source: WHO)

Les effets toxicologiques des microplastiques sur l'environnement et sur l'homme