Two decades after a marine biologist coined the term “microplastics,” researchers are still uncovering how this form of pollution affects human health.
A new study, published in the journal Immunity, identified one way in which polystyrene microplastics appear to disrupt a key immune function.
What’s happening?
Microplastics, defined as plastic particulate matter smaller than 5 millimeters, evaded notice until 2004.
Since that time, researchers have been working to learn how they impact the environment, wildlife, and human health.
According to Wired, the study was authored by an international team of researchers affiliated with Memorial Sloan-Kettering Cancer Center, a prominent and top-rated oncology facility.
In the course of the study, the authors focused on immune cells called phagocytes, white blood cells that perform an important function: consuming and clearing dead cells, foreign matter, and other pathogens from the body.
When efferocytosis — the process by which phagocytes routinely clear away unwanted cellular material — is disrupted, humans are more vulnerable to diseases, inflammation, and autoimmune conditions.
The authors observed that lab mice exposed to polystyrene microplastics had “significantly impaired” immune function. Co-author Justin Perry told Wired that the findings could explain a global dip in male fertility.
“We found that microplastics accumulate and interfere with the function of cells responsible for processing dead cells in multiple organs: lung, liver, and testis. This may be contributing to the worldwide increase in male infertility,” Perry said.
Why is this concerning?
Twenty years might sound like a significant interval for researchers, but when it comes to microplastics, studies like this show just how much we don’t know about them.
One thing that’s well established is how pervasive microplastics have become in the environment and in the bodies of animals and people.
Microplastics have consistently turned up in Earth’s most remote corners, even in places humans can’t reach. Plastic can take centuries to break down, shedding microplastics over time.
Study after study has shown that microplastics pose risks to the environment, wildlife, and people; they’ve been linked to a wide array of negative human health impacts, including heart attacks and some cancers.
One of the most insidious dangers of microplastics is their small size, given their massive impact on the environment and life on Earth, as Perry acknowledged.
“I was skeptical at first that microplastics would have any meaningful effect on phagocytosis. Now it is clear that I was wrong,” he admitted.
What’s being done about microplastics?
World leaders have for years sought to pass a global plastics treaty to rein in the production of new plastic, but talks have repeatedly stalled.
In the meantime, simply using less plastic and replacing your most-used items with non-plastic alternatives significantly reduces direct exposure.
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