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Human testicles contain microplastics and nanoplastics at levels three times higher than animal testes and human placentas, a new small study found.
“These plastics are often nano-scale, typically less than half a micron in length and maybe like 20 to 200 nanometers in width,” said toxicologist Matthew Campen, coauthor of the study that published May 15 in the journal Toxicological Sciences.
18 July 2023, Spain, Palma de Mallorca: Etienne from Biberach drinks water in hot temperatures on the beach of Arenal. For the north and east of the Spanish Mediterranean island of Mallorca, the national weather service Aemet announced maximum temperatures of at least 43 degrees. The peak of the third heat wave of the summer in Spain makes locals and tourists in the popular vacation destination sweat. Photo: Clara Margais/dpa (Photo by Clara Margais/picture alliance via Getty Images) Clara Margais/dpa/picture alliance/Getty Images
“They look like little shards, tiny broken bits from very, very old plastics,” said Campen, a regents’ professor of pharmaceutical sciences at the University of New Mexico in Albuquerque.
Such minuscule particles can invade individual cells and tissues in major organs, experts say, interrupting cellular processes and potentially depositing endocrine-disrupting chemicals such as bisphenols, phthalates, flame retardants, per- and polyfluoroalkyl substances, or PFAS, and heavy metals.
Endocrine disruptors interfere with the human reproductive system, leading to genital and reproductive malformations as well as female infertility and a decline in sperm count, according to the Endocrine Society.
In fact, sperm counts in parts of the world, including the United States, have declined by at least 50% over the past 50 years, the society stated on its website.
“This is an eyes wide open situation right now,” Campen said. “We’re just now realizing how much plastic is in our bodies. We need a surge of research around this topic to confirm or deny a role for microplastics in driving infertility, testicular cancer and other cancers.”
‘Action is desperately needed now’
The new study tested 23 preserved testes from cadavers who were ages 16 to 88 at the time of their death, then compared the levels of 12 different types of plastics in those testicles with plastics found in 47 dog testes.
“The levels of microplastic shards and types of plastics in human testes were three times greater than those found in dogs, and the dogs are eating off the floor,” Campen said. “So it really puts in perspective of what we’re putting in our own bodies.”
Polyethylene, one of the most widely used plastics in the world, was the predominant type of polymer in both species, followed by PVC, or polyvinyl chloride, another commonly used chemical that can contain chemical additives and heavy metals including phthalates, cadmium and lead. Phthalates, called “everywhere chemicals” because they are so common, are added to consumer products to make the plastic more flexible and harder to break.
Female hand taking bottle of mineral water from supermarket shelf mediaphotos/iStockphoto/Getty Images
Researchers expected to find more plastic shards in the testicles of older men in the study, but that wasn’t the case, Campen said.
“It seems that in peak reproductive years for men, which is from 20 to 45, there are higher levels of plastics, which then begin to decline after the age of 55,” he said. “This suggests the human body can eliminate these plastics.”
But there is a downside. The finding also suggests that the increased energy needs of a younger testicle may “also pull more plastic into that organ,” Campen said.
“Add to that the fact that the number of plastics we’re exposed to is doubling at a rate of every 10 to 15 years,” he said. “So what’s going to happen in 15 years when we are exposed to twice the amount or 30 years when we are exposed to four times the amount? That is why action is desperately needed now.”