Microplastics and scientific rigour are under renewed scrutiny

Researchers have responded to recent coverage questioning studies that detect microplastics in human tissues, saying methodological debate is normal and that analytical standards need strengthening.

Several researchers have written in response to recent coverage that questioned findings of microplastics in human tissues. They say constructive methodological debate is normal, essential and expected as new techniques are tested and improved. Authors emphasise the need to refine, standardise and validate analytical methods, including better ways to distinguish microplastics from lipids. They also highlight ongoing concerns about chemical exposures associated with plastics and describe coordinated efforts to raise quality standards. Key points: - Scientific re-evaluation and debate about studies reporting micro- and nanoplastics in human tissues is ongoing and described by contributors as part of normal scientific process. - Experts call for greater analytical rigour, transparency and harmonisation of methods, with attention to distinguishing microplastics from other materials such as lipids. - Some researchers report direct microscopic observations of microplastic particles in multiple human tissues and identification of polymer types. - Plastic-associated chemicals (for example, phthalates, bisphenols and brominated flame retardants) are reported to be transported by particles into the body and have been linked to health outcomes including cancer, heart disease, developmental effects and reduced fertility. - Coordinated initiatives and quality-assurance efforts are under way, including a Lancet-backed Countdown on Health and Plastics and the Metabolomics Quality Assurance and Quality Control Consortium (mQACC), to improve analyses and promote best practice. Summary: Researchers describe the field as being in a phase of reassessment focused on methodological refinement, validation and standardisation. Coordinated efforts and quality-assurance initiatives are being launched to clarify evidence and reduce uncertainty about detection methods and possible health implications.