In a disturbing revelation about the pervasiveness of plastic pollution, scientists have found microplastic particles present in every single human testicle they examined during a recent study. The researchers also detected microplastics in testes samples from pet dogs.
The study, published in the journal Toxicological Sciences, analyzed a total of 23 human testicles obtained from postmortems conducted in 2016. The men ranged in age from 16 to 88 years old at the time of death. Shockingly, each of the 23 testicle samples was contaminated with microplastic particles.
In addition, the researchers examined 47 testes samples from neutered dogs. Once again, microplastics were present in every single sample analyzed.
The concentration of microplastics was nearly three times higher in the human testicle tissue compared to the dog samples – 330 micrograms per gram versus 123 micrograms per gram, respectively. Polyethylene, commonly used in plastic bags and bottles, was the most prevalent type of microplastic identified, followed by PVC.
While the preserved human testicle samples did not allow for measurement of sperm counts, the researchers were able to analyze that metric in the dog testes. Their findings revealed lower sperm counts in the samples with higher levels of PVC contamination, though more research is still needed to conclusively prove microplastics directly cause declining sperm counts.
“PVC can release a lot of chemicals that interfere with spermatogenesis and it contains chemicals that cause endocrine disruption,” explained Prof. Xiaozhong Yu at the University of New Mexico, who led the groundbreaking study.
The discovery adds to growing concerns about the ubiquitous presence of microplastic particles contaminating the human body and environment. Microplastics have previously been detected in human blood samples, placenta tissue, and even breast milk.
While the exact health impacts remain unclear, microplastics are feared to potentially cause inflammation, cellular damage, and other deleterious effects, similar to risks associated with air pollution exposure. Just last month, doctors warned microscopic plastics in blood vessels may substantially increase risks of stroke, heart attack and premature death.
“At the beginning, I doubted whether microplastics could penetrate the reproductive system,” Yu admitted. “When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans.”
The findings correlate with decades of data showing sperm counts have declined precipitously in men across the globe. Experts have long suspected chemical pollutants like pesticides play a role, but this new research suggests microplastic contamination could be an underappreciated factor as well.
“The impact on the younger generation might be more concerning now that there is more plastic than ever in the environment,” Yu cautioned, noting the men providing testicle samples lived in a time of far less plastic production and waste compared to today.
While this study is the first to find microplastics present in human testicles, it builds on preliminary research published last year detecting the particles in semen samples from men in China. Animal studies have also linked microplastic exposure to reduced sperm quality, hormonal imbalances and other reproductive issues.
As the ubiquity of microplastics becomes increasingly apparent, experts say much more research is urgently needed to fully understand the potential health ramifications and determine if regulatory actions may be required to limit human contamination from these persistent pollutants.
For many scientists, the violation of the male reproductive system by synthetic particles represents a sobering new frontier in the world’s plastics crisis. The findings once again underscore that older, disposable habits centered around single-use plastics come with hidden costs that may span generations.