Every human testicle examined in a new study contained microplastics

Harmful microplastics are detectable not only in the lungs, bloodstreams and placenta, but also in human testicles, according to a study published in the journal Toxicological Sciences.

After obtaining 23 postmortem human testicles and 47 dog testicles from veterinary castrations, researchers used a process called pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), in which samples were heated to the point of decomposition. What remained was then separated and examined with highly sensitive equipment for the presence of microplastics.

The results were extremely disturbing. All testicles examined – dogs and humans – contained measurable amounts of microplastic material. Although researchers noted “significant inter-individual variability” in their sources, human testicles averaged nearly three times higher plastic concentrations than dogs: 330 micrograms per gram versus 123 micrograms per gram. They also identified twelve different types of microplastics in the testicles, with polyethylene (used to make plastic bottles and bags) being the most common.

[Related: Microplastics have officially been found in our bodies.]

“At first, I doubted whether microplastics could enter the reproductive system,” said co-author Xiaozhong Yu during a recent interview with The guard. “When I first received the results for dogs, I was surprised. I was even more surprised when I received the results for humans.”

Researchers say these new findings could support a current theory that microplastics are contributing to the global decline in total sperm counts. For example, PVC has also been found in the testicles and has been linked to interference with spermatogenesis and endocrine problems. Although the full extent of the health effects of microplastics is not yet known, evidence strongly suggests so the particles can increase the risk of heart attacks and strokes, among other complications such as tissue inflammation.

The age range for human samples came from males between 16 and 88 years old, but the team raised specific concerns about the younger generations, given the decades-long increase in the amount of plastic pollution generated around the world. It’s disturbing news, but considering microplastics are now being found at the bottom of the ocean on top of Mount Everestit probably shouldn’t be surprising that they also stay in much more personal places.