Small plastic particles are everywhere: in the soil where our food is grown, in the water we drink and in the air we breathe. They got there from the plastic we throw away, which ends up in landfill sites, rivers and seas. There the plastic waste slowly breaks down, releasing tiny particles called microplastics and even tinier nanoplastics into the environment.
Microplastics are also increasingly being found throughout the human body. We are not sure how they got there, though there are three probable routes. We may ingest microplastics when we eat and drink, or breathe them into our lungs, or absorb them through our skin. Another route has recently been suggested, whereby microplastics get up our noses and from there into our brains.
For a long time, it was thought that the human brain existed in splendid isolation from the rest of the body. The so-called blood-brain barrier, a special layer of cells, protects the brain from all manner of pathogens and harmful substances. However, we now know that the blood-brain barrier can be breached because small plastic particles have been found in the human brain.
