Microplastics: State of the Evidence on Health Effects and Public Perception

Microplastics, i.e., plastic particles ranging from 1 μm to 5 mm in size, are ubiquitous in the environment. They are to be distinguished from nanoplastics, which are defined as particles less than 1 μm or less than 100 nm in size (depending on the study). Microplastics have increasingly become a topic of discussion in the media. In this article we present the state of scientific and medical knowledge about microplastics and how they are perceived by the public.

This narrative review is based on pertinent publications retrieved by a search in PubMed and Scopus, supplemented by the findings of a random-quota online survey among the Germanspeaking population (N = 1135).

Microplastic particles mainly enter the body by being inhaled or swallowed. According to current knowledge, most are excreted without being resorbed, while a small fraction of them could reach the tissues or the bloodstream depending on their size and become systemically bioavailable. Approximately 0.3% of particles measuring 1-10 μm in size are resorbed in the intestinal tract. Microplastics have been found in organs and tissues (e.g., placenta, atherosclerotic plaques), but no causal relation between their uptake and any health effects has yet been proven. Given the limited available evidence on microplastics, some segments of the general population are concerned about their potential effects on human health. In our random-quota survey, 84% of respondents considered the statement that microplastics in the body can worsen pre-existing medical conditions to be true.

Current evidence does not permit any definitive conclusion about the effects of microplastics on health. The information presented here may help physicians counsel their patients on this matter.