By Marie-Josée Roy
Tiny particles of plastic are everywhere in the environment, and because of their potential effects on human health, they often make the headlines. To get the facts, we consulted Daniel G. Cyr, a toxicologist and professor at the Centre Armand-Frappier Santé Biotechnologie in Laval, Que., part of the Institut national de la recherche scientifique (National institute of scientific research).
What are microplastics, and where do they come from?
Microplastics are particles that measure between one micrometre [a thousandth of a millimetre] and five millimetres. There are also nanoplastics, which are particles measuring less than one micrometre. Most come from the breaking down of plastics in the environment, but we also find them in products such as cosmetics.
How are we exposed to them?
They enter our bodies when we ingest or inhale them. Nanoplastics can also be absorbed by the skin. These tiny particles are found in the food we eat, in the air we breathe, and on objects we touch. In a stream, for example, invertebrates absorb microplastics as they eat; the invertebrates are in turn eaten by fish, which are then caught and eaten by humans. In this way, microplastics move up the food chain.
How do they affect our health?
Microplastics are found throughout the human body: in the brain, in the testicles, in the placenta, in women’s reproductive organs, in the intestines…. Researchers in New Mexico recently published a study showing that people with Alzheimer’s disease had a higher level of microplastics in their brain than do other people. There are also reports on the effects of microplastics on hormones: chemicals called endocrine disruptors can join forces with nanoplastics and be released into the reproductive organs, where they can hinder or alter the functioning of hormones. We’re starting to study this kind of connection.
How can we help to limit microplastics in the environment?
The idea is to try to reduce the amount of plastic material that is put in the garbage. As it breaks down, plastic that is discarded in the environment becomes more toxic. It’s best to recycle plastics and to choose other materials when possible.
