It has been found that not only is there weedkiller in human sperm, but microplastics have been found in human testicles, indicating that microplastics are either in human sperm or impacting upon them. The problem here is that microplastics have been linked to cancer, and it is a good bet that their contamination would reduce sperm quality, leading to further problems of fertility. It is an under-discussed problem that human sperm counts fell on average by 1.2per year between 1973 to 2018 and since the year 2000, the rate of decline was more than 2.6% percent per year: https://www.bbc.com/future/article/20230327-how-pollution-is-causing-a-male-fertility-crisis.
Even given every other crisis, this is a challenging existential threat.
https://www.ign.com/articles/microplastics-found-in-every-human-testicle-examined-in-new-study
"Scientists have found significant quantities of microplastics present in human and canine testicles, raising concerns surrounding their potential impact on the human reproductive system.
Microplastics are tiny pieces of debris that form when larger human-made plastic items such as carrier bags are exposed to ultraviolet radiation from the sun, which causes them to disintegrate. They can also be created intentionally as part of a commercial product, or through the ware and tear of synthetic objects like tyres, or items of clothing. To date, microplastics have been found marring countless natural environments, ranging from frigid polar regions to the heights of Mount Everest, and the deepest depths of the Mariana Trench.
Wherever they go, they disrupt the natural ecosystem in subtle but insidious ways. To make matters worse, microplastics have even been found polluting our bodies - including the heart, placenta, liver, and kidneys - after being inhaled through the air, or consumed in trace amounts through food and drink.
"We don't want to scare people," said professor Xiaozhong "John" Yu of the University of New Mexico, who led the new study that examined the presence of the pollutant in human and canine reproductive organs. "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 behaviour."
The new research published in the journal Toxological Sciences saw professor Yu and his colleagues analyze 47 canine testicles sourced from neutered animals and 23 human testes that had been anonymously obtained from donors through the New Mexico Office of the Medical Investigator.
Each of the testicles was first exposed to chemicals that dissolved the organ's fat and protein. The remaining matter was then spun in a centrifuge to separate out the microplastics polluting the organs. The microplastics were then heated to 600 degrees Celsius while being observed by a mass spectrometer, which analyzed the gases emitted by the synthetic pellet to provide a breakdown of its makeup.
"At the beginning, I doubted whether microplastics could penetrate the reproductive system," explained professor Yu. "When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans."
It was discovered that every single one of the testicles examined during the study contained a significant amount of microplastics. The human testicles in particular contained an abundance of the pollutant (329.44 micrograms), which was three times higher than the average microplastic content of the average canine testicle (122.63 micrograms). A grand total of 12 different microplastics were found in the reproductive organs, with the most common being the polymer polyethylene, which is used in the creation of plastic bottles.
The researchers were also able to perform a sperm count on the canine testicles, but were unable to do the same for the human samples, which had been chemically preserved. It was found that animals with a higher amount of the microplastic PVC in their organs had a correspondingly lower sperm count, but that polyethylene seemed not to create a similar effect.
"Compared to rats and other animals, dogs are closer to humans," said Yu. "Physically, their spermatogenesis is closer to humans and the concentration has more similarity to humans." Canine sperm counts also seem to be dropping, he added. "We believe dogs and humans share common environmental factors that contribute to their decline."
Professor Yu also noted that the average human donor had been around 35-years-old, which accounted for the effects of just a few decades of microplastic accumulation. Given that microplastics are more prevalent in the present day, there exists a "concerning" possibility that younger generations may see a greater impact from the pollutant."