A peer-reviewed study published last week in the official journal of the Society of Toxicology indicated that human and canine testicles are teeming with microplastics. This may help account for the precipitous global decline in male fertility.
Awash in microplastics
Nature Medicine noted in an editorial last month that the "world is awash" with over 6 billion tons of plastic.
'MNPs are found everywhere on the planet, including the oceans, air, and food supply.'
Roughly 353 million tons of plastic waste were produced in 2019 alone. Nature Medicine indicated that's particularly bad news since plastics contain over 10,000 chemicals, including endocrine disruptors and cancer-causing carcinogens, and can easily steal into the human body.
Plastics find their way into the human body in the form of tiny particles called microplastics (less than 5 mm in diameter) and nanoplastics (less than 1 μm in diameter). Microplastics and nanoplastics (MNPs) can arise from a variety of sources, including by design, as in the case of microbeads used in cosmetic and personal care products, or inadvertently, as the result of degradation of larger plastic products, such as through the laundering of synthetic clothes or abrasion of tires. MNPs are found everywhere on the planet, including the oceans, air and food supply.
Blaze News previously detailed the findings of an Australian June 2023 study that suggested humans might be inhaling roughly 16.2 bits of plastic every hour — enough to make a credit card per week. These credit cards can prove costly.
According to the scientific journal, microplastics have been shown in rodent studies to adversely impact various organs, including the intestine, lungs, and liver along with the reproductive and nervous systems.
In terms of their impact on human beings — where they have been found polluting various organs along with placenta and breast milk — researchers have identified links between microplastics and various health conditions, including cardiovascular disease and inflammatory bowel disease.
It appears scientists may have come across yet another troubling link.
Devaluing the family jewels
Blaze News previously reported that sperm counts have been trending downward in men on every continent since at least 1973.
A 2022 peer-reviewed study published in the journal Human Reproduction Update confirmed a trend detailed by the same researchers years earlier in a groundbreaking meta-analysis. The researchers indicated that "this world-wide decline is continuing in the 21st century at an accelerated pace."
The study, led by Dr. Hagai Levine of the Hebrew University of Jerusalem and Dr. Shanna Swan of the Icahn School of Medicine at Mount Sinai, revealed that the trend was "driven by a 50%-60% decline among men" in North America, Europe, Australia, and New Zealand.
After combining the findings from over 250 other studies and increasing their sample size — so as to include men not already worried about their fertility — the researchers determined that between 1973 and 2018, sperm counts "declined appreciably," not just in Western men but in 53 countries across the world.
The sperm count decline has "become steeper since 2000," dropping by 1.4% per year and by 62.3% overall.
Declining sperm counts have been attributed to various factors, including chlormequat chloride, an agricultural chemical found in oat-based foods; mobile phone radiation exposure; and certain vaccines.
Microplastics are evidently another contender.
Plastic baggage
Researchers at the University of New Mexico recently studied 47 canine and 23 human testes. Every single testicle contained microplastics, polyethylene — used to make plastic bags and bottles — being the most prevalent.
'When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans.'
According to the University of New Mexico, the researchers chemically treated the testicle samples to dissolve the fat and proteins. They then spun each sample in an "ultracentrifuge, leaving a nugget of plastic at the bottom of a tube. Then, heated the plastic pellet in a metal cup to 600 degrees Celsius. They used a mass spectrometer to analyze gas emissions as different types of plastic burned at specific temperatures."
They found that the average concentration of microplastics in testicular tissue were 122.63 micrograms per gram in dogs and 328.44 micrograms per gram in humans.
"At the beginning, I doubted whether microplastics could penetrate the reproductive system," said Dr. Xiaozhong Yu, head of the research team. "When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans."
Matthew Campen, one of the authors of the study, told NPR the tiny particles are "shard-like, stabby bits."
The human testicles, which the Guardian reported were taken from the corpses of men between the ages of 16 and 88, had been chemically preserved such that their sperm count could not be measured. Researchers were, however, able to assess whether higher plastic contamination in the dog's testes corresponded with lower sperm counts.
Researcers found that high levels of PVC — the second-most prevalent polymer in dogs — correlated with a lower sperm count.
"The plastic makes a difference — what type of plastic might be correlated with potential function," said Yu. "PVC can release a lot of chemicals that interfere with spermatogenesis, and it contains chemicals that cause endocrine disruption."
The research team examined canine testicles in particular because "compared to rats and other animals, dogs are cloer to humans," said Yu. "We believe dogs and humans share common environmental factors that contribute to their decline.
"We don't want to scare people," continued Yu. "We want to scientifically provide the data and make people aware there are a lot of microplastics. We can make our own choices to better avoid exposures, change our lifestyle and change our behavior."
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