For the first time, microplastics have been found in the penis, raising questions about their possible role in erectile dysfunction.
This revelation comes after pollutants were recently found in testes and semen. Experts say male fertility has declined in recent decades and more research is needed on the potential harm of microplastics to reproduction.
The penis may be particularly vulnerable to microplastic contamination, because blood flow is high during an erection, the researchers said. People ingest microplastics through food, drink and breathing, and microscopic particles have also been found in the blood.
The study evaluated tissues taken from five men who were undergoing surgery related to erectile dysfunction. Microplastics were found in four cases, with PET and polypropylene being the most prevalent. Both are used in food and beverage packaging and other everyday items.
There appears to be widespread contamination of people's bodies with microplastics, with scientists finding microplastics wherever they look. The effects on health are still unknown, but microplastics have been found to damage human cells in the laboratory.
These particles can cause inflammation in tissues, as air pollution particles do, and the chemicals in plastics can also cause damage. Doctors found that people whose arteries were contaminated with microplastics had a significantly increased risk of death from stroke and heart attack.
Millions of tons of plastic waste are dumped into the environment every year, and much of it turns into microplastics. This has polluted the entire planet, from the top of Mount Everest to the deepest oceans.
Dr Ranjith Ramasamy, who led the new research at the University of Miami in the US, said: “The penis is a vascular, spongy organ, so is definitely vulnerable. During an erection, up to a fifth of the entire body's blood volume is pumped into the penis.”
He added: “We know that erectile dysfunction depends on many factors. To have an erection you need good hormones, nerves, blood supply and good smooth muscle tissue.
“We found that microplastics were present in the smooth muscle of the penis. We just know that they shouldn't be there, and we suspect this may lead to smooth muscle dysfunction.”
Ramasamy said more research is urgently needed to explore the possible role of microplastics in erectile dysfunction and male infertility. Sperm counts in men have been falling for decades and there is still no explanation for the 40% lower number, although several studies have blamed chemical pollution. Recent studies on mice have shown that microplastics reduced sperm counts and caused abnormalities and hormone disruption.
Ramasamy said: “We have moved from whether we have microplastics inside us, to whether the levels of microplastics are high enough that things become pathogenic.”
The new research, published in IJIR: Your Sexual Medicine journal, analysed tissue samples taken from five men who were undergoing surgery for an inflatable penile prosthesis, a treatment option for men with severe erectile dysfunction. The size of the microplastics detected ranged from 0.5 mm to 0.002 mm.
The widespread use of microplastics is worrying, and it is important to understand their potential impact on human health, the researchers said.
Ramasamy said: “As a society, we need to understand that drinking water from plastic bottles, bringing food in plastic containers and, even worse, microwaving food in plastic containers, is promoting things in our bodies that shouldn't be there. And the penis is one organ that everyone will pay attention to.”