Tiny plastic particles have now been discovered in an unexpected place — the human brain.

A recent study highlights the alarming presence of the particles, known as microplastics, in human organs, particularly the brain, raising concerns about their potential health effects.

The study investigated the increasing levels of micro and nano plastics in the environment and their potential effects on human health. Researchers examined the tiny, shard-like particles in the liver, kidneys, and brain using autopsy samples collected at Albuquerque, New Mexico, between 2016 and 2024. The brain samples were taken from the frontal cortex, which is responsible for abstract thinking, creativity, and motor tasks.

Results showed that the brain had higher concentrations of microplastics compared to the liver or kidneys, with the amount of plastic in all organs increasing significantly over time. The lead study author and regents’ professor of pharmaceutical sciences at the University of New Mexico, Matthew Campen, told CNN that in the brain tissue of “normal individuals” aged 45 to 50 years, plastic particles were found at a concentration of 4,800 micrograms per gram, making up about 0.5 percent of the tissue’s weight.

“Compared to autopsy brain samples from 2016, that’s about 50 percent higher,” he said. “That would mean that our brains today are 99.5 percent brain and the rest is plastic.”

The study identified polyethylene as the most common type of plastic found, with greater amounts detected in the brain compared to other tissues. Polyethylene is widely used in packaging, plastic bags, storage containers, and toys.