It's widely cited on both sides of the microplastics debate. Here's what it actually says.
In August 2019, the World Health Organization published a review of 50 studies reporting microplastic concentrations in drinking water or its freshwater sources [1]. It's one of the most cited documents in this space, and it's frequently summarized in two opposite, equally incomplete ways: "WHO says microplastics are dangerous" and "WHO says microplastics are fine." Neither is accurate.
The report evaluated three distinct hazard pathways: the physical particles themselves, chemicals associated with the particles (both plastic additives and environmental contaminants that can adsorb onto particle surfaces), and microorganisms that can form biofilms on particle surfaces. Based on the evidence available at the time, WHO found no data suggesting overt health concern from the particles themselves, a low health concern from associated chemicals, and no evidence of risk from biofilm-related microorganisms.
The report is explicit that this is a statement about the limits of available evidence, not a clean bill of health — it explicitly calls for standardized measurement methods and more research as a precondition for a more confident assessment. That distinction is why the MPFREE Standard's claims policy (see the certification-and-standards articles) never uses absolute safety language: certification denotes conformance to a tested, published threshold, not a scientific finding about human health outcomes, which — per WHO's own 2019 assessment — remains an open research question rather than a settled one.