Potentially harmful microplastics found in human testis

Last month, a Toxicology Sciences study found microplastics in human and dog testis. The presence of microplastics there could have “potential consequences on male fertility.” Microplastics are tiny particles of plastic. Anything less than 5mm is considered a microplastic, but particles can get as small as one nanometer. Scientists have “located microplastics all over the globe, from the floor of the Mariana Trench to the summit of Mount Everest.” In recent years, they’ve even found them in human bloodstreams. So, how do microplastics enter your bodies, and should you be concerned when they do?

How do microplastics get into our bodies?

Microplastics are airborne, in the ocean, and in the soil. As a result, they end up in our food and drinking water. We’ve produced 8.3 billion metric tons of plastic since the ‘50s, so there’s no feasible way to avoid microplastic infiltration now. How did this happen?

Consider a plastic bag that escapes a dumpster and hitches a ride on a passing breeze. It wanders in the wind and settles in a ditch somewhere, where rain and water eventually carry it into the sea. Years and years pass, and instead of being re-integrated into an ecosystem, it gets torn apart into fibers smaller than a human hair. It never really goes away. Then, the plastic waste enters the stomach of a fish. Someone eats the fish, and it gets into their digestive tract. Hopefully, the diner will expel the intruder. But microplastics don’t just enter our bodies through food; they enter the blood and lungs through respiration.

Microplastics have been found in human

• placentas,
• arterial plaque,
• lungs,
• blood,
• and now, testis.

That’s worrying, but before getting terribly frightened, consider that an average human breathes in around 50 billion dust particles an hour. That’s a lot, but it’s not very much in weight—it measures in the milligrams. Your body uses mucus and coughing to eject outside particles, including microplastics, all the time without you thinking about it. The human body is wonderfully complex and does an excellent job of defending itself.

That said, are microplastics harmful to the human body?

How harmful are microplastics?

Although finding microplastics in animals’ and humans’ lungs, blood, and, now, the testis is concerning, it doesn’t yet constitute a crisis. More research needs to solidify the evidence of harm, though early returns suggest that there are already some health problems tied to microplastics.

• Scientific American reports on one study published in March 2024: “People who had tiny plastic particles lodged in a key blood vessel were more likely to experience serious health problems or die during a three-year study.” The authors of the study caution that their research is suggestive and worrying but not conclusive.
• Microplastics have been found to harm human cells in lab testing. The “irregular shape” of the microplastic particles predicted faster cell death and less cell viability.
• According to National Geographic, some scientists suggest that microplastics could potentially “cause irritation that leads to a cascading range of symptoms from inflammation to infection to cancer.” However, they also stress that “they could remain as an inert presence and do nothing.” This highlights the need for further research to fully understand the potential health impacts of microplastics.
• The study Toxicology Sciences reports that dogs with microplastics in their testis have lower sperm counts. There has been a worrying trend of lower sperm counts over the past couple of decades as the prevalence of microplastics has increased. That said, microplastics are far from the only explanation for that trend, so it could be an issue of correlation rather than causation. We’re still uncertain if they’re related.

We don’t want medical science to repeat the snail’s pace of proving the ill effects of smoking—especially since microplastics, if harmful, will be near-impossible to remove from our surroundings. So, countless labs worldwide are conducting rigorous studies on microplastics. Meanwhile, international policymakers are trying to reduce mass plastic production and pollution.

A Christian’s dual concern

God created Adam and Eve to tend the Garden of Eden and co-rule over the planet (Genesis 1:28). This has sometimes been called the creation care mandate. For Christians, this mandate to care for the Earth persists today. If nothing else, our habits today that affect our children, and children’s children, and our children’s children’s children, should concern us.

When they were invented, plastics were heralded as miraculous. Scientific progress delivered yet another glorious victory to humanity, growing expediency, efficiency, cheaper food, countless jobs, and many other benefits. Modern life would look radically different without plastic. Back then, we didn’t know the negative consequences of mass-producing plastic, and, in a way, we still don’t.

We should remain concerned with the well-being of animals, global and local ecosystems, and nature. But, our scientific knowledge and ability to change our society’s harmful habits are limited. In other words, we don’t live in an ideal world. We live in a fallen earth where great prosperity may entail unintended consequences centuries down the line.

Any existential worries about our future should always turn us back to hope born from our calling to help usher in the reign of God’s perfect kingdom. Let us long together for the perfect new creation promised by God. As such, Christians have a dual concern–to care for creation now and to hope for the new creation in the future.