High-profile studies reporting the presence of microplastics throughout the human body have been thrown into doubt by scientists who say the discoveries are probably the result of contamination and false positives. One chemist called the concerns “a bombshell”.
A number of prominent studies that reported the alarming discovery of microplastics and nanoplastics (MNPs) in human brains, testes, placentas, and arteries are facing intense scrutiny from scientists who contend the findings are likely the result of contamination, false positives, and rushed methodologies in a fiercely competitive field.
Researchers have formally challenged at least seven such studies, with one recent analysis listing 18 papers that may have confused human tissue signals with plastic, leading one chemist, Roger Kuhlman, to call the doubts a “bombshell” that forces a re-evaluation of what is truly known. Particular criticism has focused on a widely publicized study about rising plastic levels in brain tissue, which one scientist, Dr. Dušan Materić, dismissed bluntly: “The brain microplastic paper is a joke,” citing the high fat content in brains as a known source of false positives for certain plastics.
While experts agree plastic pollution is ubiquitous, they warn that the analytical techniques, especially Py-GC-MS, are at their limit for human tissue and that the failure to follow standard quality controls—like using blank samples to check for background contamination—has produced biologically implausible results, with Dr. Cassandra Rauert stating that “a lot of the concentrations being reported are completely unrealistic.” The senior author of the challenged brain study, Prof. Matthew Campen, defended the work as part of an emerging field, stating that most criticism has been “conjectural and not buffeted by actual data,” but the broader scientific concern is that flawed evidence could lead to misguided policies or be exploited by industry lobbyists, even as researchers stress the urgent need for robust, collaborative science to determine the true health risks of plastic inside the human body.