Microplastics have been found in human testicles, with researchers saying the discovery could be linked to declining sperm counts in men.
The scientists tested 23 human testes, as well as 47 testes from pet dogs. They found microplastic contamination in every sample.
The human testicles were preserved and thus their sperm count could not be measured. However, the sperm count in the dogs’ testes could be assessed and was lower in samples with higher contamination with PVC. The study shows a correlation, but further research is needed to prove that microplastics cause sperm counts to drop.
Sperm counts in men were falling for decadeswith chemical pollution such as pesticides implied by many studies. Microplastics have also recently been discovered in human blood, placentas and Breast milk, indicating widespread contamination of people’s bodies. The impact on health is still unknown, but Microplastics have been shown to cause damage to human cells in the laboratory.
Large amounts of plastic waste are dumped into the environment and microplastics have polluted the entire planet, from the summit of Mount Everest after the deepest oceans. Humans are known to ingest the small particles via food and water as well as breathe them in.
The particles can get stuck in tissue and cause inflammation, like air pollution particles do, or chemicals in the plastic can cause damage. In March, doctors warned of potentially life-threatening consequences after finding a significantly increased risk of stroke, heart attack and earlier death in people whose blood vessels were contaminated with microscopic plastic.
“At the beginning, I doubted whether microplastics could enter the reproductive system,” said Prof Xiaozhong Yu, at the University of New Mexico in the US. “When I first received the results for dogs, I was surprised. I was even more surprised when I received the results for people.”
The testes analyzed were obtained from post-mortem examinations in 2016, with the men ranging in age from 16 to 88 when they died. “The impact on the younger generation may be more worrisome” now that there is more plastic than ever in the environment, Yu said.
The study, published in the journal Toxicological Sciences, involves dissolving the tissue samples and then analyzing the plastic that remains. The dogs’ testes were obtained from veterinary practices that performed sterilization operations.
The human testicles had a plastic concentration almost three times higher than that found in the dog tests: 330 micrograms per gram of tissue compared to 123 micrograms. Polyethylene, used in plastic bags and bottles, was the most common microplastic found, followed by PVC.
to newsletter promotion
“PVC can release many chemicals that interfere with spermatogenesis and it contains chemicals that cause endocrine disruption,” Yu said. The human testes were routinely collected by the New Mexico Office of the Medical Examiner and were available after a seven-year storage requirement after which the samples are usually discarded.
A smaller study in China in 2023 as well found microplastics in six human testes and 30 semen samples. Recent studies in mice have reported that microplastics decreased sperm count and caused abnormalities and hormone disorders.
