Scientists have increasingly detected microplastic particles throughout the human body, including the brain, blood, cardiovascular system, liver, kidneys, stomach, lungs, testicles, and placenta. While the presence of plastic in human tissue is definitive, the "million-dollar question" is what effect these particles are having on human health. Experts highlight the urgency of understanding these effects, comparing the situation to early concerns about tobacco and asbestos. Kara Meister, an assistant professor at Stanford University, found microplastic particles in all tonsils she removed from children, prompting questions about their health impact or if they are merely "innocent bystanders."
However, the scientific community faces significant challenges and debates regarding the detection and measurement of microplastics. Some high-profile studies on microplastic presence in the human body have been questioned due to potential contamination and false positives, with one chemist calling these concerns a "bombshell." Experts point to flaws in methodologies and measurement techniques, such as lipids in the body being mistaken for polyethylene during visual detection. Ambient microplastic particles also pose a risk of contamination during research, as these particles are ubiquitous in food, water, dust, and air, and can be shed by lab instruments and clothing.
Despite these challenges, analytical techniques are improving, and some studies are beginning to link microplastic presence to health outcomes. A 2024 study, for example, found small plastic particles, primarily nanoplastics, in the artery plaque of 150 out of 257 people. Those with detected plastic particles had a nearly five times higher risk of heart attack, stroke, or death over a 34-month follow-up period. The complexities of evaluating these particles, which are invisible to the naked eye (microplastics are smaller than five millimeters, nanoplastics smaller than one micrometer), necessitate the use of "orthogonal methods," or multiple approaches, to confirm findings and advance understanding in this relatively new and evolving field.
