One of The reason plastic has become so ubiquitous is that, generally, it is very chemically stable, meaning it does not react easily with substances around it. This is why this material is so often used for food packaging and water bottles.
The same was thought to be true for microplastics, the tiny bits of debris that break off from larger plastic objects and which, according to numerous studies, have become widespread in virtually every ecosystem on the planet. But scientists from Columbia University and UC Berkeley have just discovered that water can make microplastic surfaces chemically active and turn them into a potential hazard.
According to the conclusions of the article published in Nature, this activity can trigger the spontaneous formation of chemicals capable of altering other molecules, such as those essential to living organisms. The phenomenon, the authors note, occurs even under normal environmental conditions, without the need for sunlight or other agents that cause plastic degradation.
So how can microplastics be so reactive when larger plastics generally aren’t? Scientists suggest this is due to the greater surface area available for these reactions to occur.
“As plastic fragments into smaller and smaller particles, its surface area increases enormously,” Wei Min, professor of chemistry and biomedical engineering at Columbia University, said in a press release. “Then, microplastics modify the water around them, generating high-energy reactive radicals that most likely contribute to the biological damage we see in animals and potentially in humans following exposure to microplastics.”
Among these potentially dangerous chemicals, called reactive oxygen species, stands out a variety known as hydroxyl radicals. They are particularly dangerous because they can strip electrons from the proteins and fats that make up cell membranes, disrupting their structure and function. These are “classic examples of the types of molecules that can damage animal and human tissues,” added Naixin Qian, a postdoctoral researcher in Min’s lab who helped lead the research.
Our body has certain defenses against this type of damage. This is the biological function of buzzing molecules known as antioxidants. These neutralize reactive chemicals, but if the reactive compounds greatly outnumber the antioxidants, this line of defense can be overwhelmed.
This can progress to a scenario called oxidative stress, leading to cell damage. Previous research has already identified oxidative stress among the cellular responses associated with exposure to microplastics, although the mechanisms responsible for this damage are not yet fully understood.
Gn Health
