Detection is not the same claim as harm. Both parts matter.
In 2021, researchers reported the first documented detection of microplastic particles in human placental tissue, using electron microscopy on delivered placentas donated with informed consent [1]. It was a detection study, not a health-outcome study — it established that the particles were present and where in the tissue they were found, not what effect, if any, they had.
A larger 2024 study extended this considerably: researchers at the University of New Mexico reported microplastics in all 62 placenta samples tested, with concentrations ranging from 6.5 to 790 micrograms per gram of tissue [2]. That range is wide, and the study's authors have been clear that concentration detected is not, by itself, evidence of a specific health effect.
What they establish: microplastic particles are now routinely detectable in human tissue that was previously assumed to be a relatively protected environment, using currently available detection methods. What they don't establish, on their own: a dose-response relationship, a causal health outcome, or a safe versus unsafe exposure threshold for humans.
This is a live, fast-moving area of research, and it's precisely why the MPFREE Standard doesn't make health-outcome claims of any kind — only tested-threshold claims for specific matrices and methods. A certification mark that gets ahead of the actual state of toxicology research isn't more protective; it's a liability the moment the research catches up, in either direction.