Microplastics found in every human testicle in study | Plastics

Microplastics have been discovered in human testicles, with researchers saying the finding could be linked to lower sperm counts in men.

The scientists tested 23 human testicles, as well as 47 pet dog testicles. They found microplastic pollution in each sample.

The human testicles had been preserved and so their sperm count could not be measured. However, the number of sperm in the dogs’ testicles could be assessed and was lower in samples with higher PVC contamination. The study demonstrates a correlation, but more research is needed to prove that microplastics cause lower sperm counts.

Sperm counts in men have been declining for decades, with chemical pollution such as pesticides implicated by many studies. Microplastics have also recently been discovered in human blood, placenta and breast milk, indicating widespread contamination of the human body. The health impact is still unknown, but microplastics have been shown in the laboratory to damage human cells.

Large amounts of plastic waste are dumped into the environment and microplastics have polluted the entire planet, from the summit of Everest to the deepest oceans. People are known to consume the tiny particles through food and water and breathe them in.

The particles could lodge in tissues and cause inflammation, as air pollution particles do, or chemicals in plastics could be harmful. In March, doctors warned of potentially fatal effects after finding a significantly increased risk of stroke, heart attack and early death in people whose blood vessels were contaminated with microscopic plastics.

“At first I doubted whether microplastics could enter the reproductive system,” said Professor Xiaozhong Yu, from the University of New Mexico in the United States. “When I first received the results about the dogs, I was surprised. I was even more surprised when I received the results in humans.

The testicles analyzed were obtained from autopsies performed in 2016, with the men ranging in age from 16 to 88 years old at the time of death. “The impact on the younger generation might be more concerning” now that there is more plastic than ever in the environment, Yu said.

The study, published in the journal Toxicological Sciences, involved dissolving the tissue samples and then analyzing the remaining plastic. The dogs’ testicles were obtained from veterinary practices that had carried out sterilization operations.

Human testes had a plastic concentration almost three times higher than that found in dog testes: 330 micrograms per gram of tissue compared to 123 micrograms. Polyethylene, used in plastic bags and bottles, was the most commonly found microplastic, followed by PVC.

“PVC can release many chemicals that interfere with spermatogenesis and contains chemicals that cause endocrine disruption,” Yu said. The human testes had been routinely collected by the New Mexico Medical Investigator’s Office and were available after a storage period of seven years, after which the samples are usually discarded.

A smaller study conducted in China in 2023 also found microplastics in six human testicles and 30 semen samples. Recent studies in mice have shown that microplastics reduced sperm counts and caused abnormalities and hormonal disruptions.