Dr. Garcia is part of a leading lab, run by toxicologist Matthew Campen, that is studying how tiny particles known as microplastics accumulate in our bodies. The researchers’ most recent paper, published in February in Nature Medicine, generated a string of alarmed headlines and buzz in the scientific community: They found that human brain samples from 2024 had nearly 50 percent more microplastics than brain samples from 2016.
Some of the researchers’ other findings have also prompted widespread concern. In the study, the brains of people with dementia had far more microplastics than the brains of people without it. In papers last year, the researchers showed that microplastics were present in human testes and placentas. Other scientists have also documented them in blood, semen, breast milk and even a baby’s first stool.
Also in February, along with colleagues from Baylor College of Medicine and Texas Children’s Hospital, Dr. Campen’s lab released preliminary research showing that the placentas of babies who were delivered preterm contained more microplastics than those of babies delivered at full term, despite having had less time for those particles to accumulate.
Going Back Decades
Researchers can’t say for certain how these plastics are getting into our bodies or where they originated, but they have some clues. They know that plastic waste ends up in our soil, water, air and even rain, said Christy Tyler, a professor of environmental science at the Rochester Institute of Technology who studies microplastics in aquatic ecosystems. It may be incorporated into plants and concentrated as it moves up the food chain. Plastic is in our clothes, our rugs, our couches and our food storage containers — “really, it’s everywhere,” Dr. Tyler said.
The characteristics of the plastics Dr. Campen’s team found in human tissue suggest they came primarily from waste that was produced many years ago and was weathered over time. The researchers found a significant amount of polyethylene, for example, the dominant type of plastic produced in the 1960s, but less of the plastic used in water bottles, which took off in the 1990s.
Because plastic production has doubled every 10 to 15 years, even if we were to stop making it today, so much plastic is already in use that more and more plastic waste would accumulate in the environment and, potentially, in our bodies for decades to come.
Dr. Campen suspects the main way these plastics get inside our bodies is when we ingest them, long after they’ve been discarded and started to break down. He is less concerned about so-called fresh plastics, like those that slough off cutting boards and water bottles as we are using them, because those particles are much larger and newer than what he has measured. And research suggests that the body clears out some larger microplastics.
Dr. Campen acknowledged that his view on fresh plastics was “unconventional,” and other scientists say it’s worth taking steps to reduce your exposure. It’s clear that microplastics can leach out of water bottles, microwaved food containers and synthetic clothing, and research from animal studies suggests these particles could be harmful, said Tracey Woodruff, director of the program on reproductive health and the environment at the University of California, San Francisco.
“Maybe more of it is coming from this degraded microplastic, but that doesn’t mean you’re not getting exposed from these other, fresher microplastics,” Dr. Woodruff said. Larger particles can still affect the gut, which might then affect the rest of the body, Dr. Campen said.
Now they are ready to explore possible links between certain doses and human health outcomes, such as heart disease, fertility issues and multiple sclerosis.
One day, some of it could end up in us.
Leave a Reply