Human Consumption of Microplastics.
Level 4 - case-series / case-control
Level assigned by design analogy: exposure modeling synthesis aggregating heterogeneous cross-sectional contamination measurements without direct human clinical outcomes.
PubMed 31184127 · doi:10.1021/acs.est.9b01517
What was done
The authors estimated annual human microplastic intake by synthesizing data on microplastic particle concentrations in commonly consumed foods and drinking water alongside inhalation rates, referenced against recommended dietary guidelines for the American population. The quantitative exposure model analyzed 402 data points extracted from 26 published studies encompassing over 3,600 processed samples, covering roughly 15% of caloric intake in the United States.
What was found
Estimated annual microplastic ingestion via dietary sources alone ranged from 39,000 to 52,000 particles per person depending on age and sex. When inhalation estimates were incorporated, total annual exposure increased to between 74,000 and 121,000 particles. Drinking water source substantially altered exposure: meeting recommended fluid intake exclusively through bottled water was estimated to add 90,000 microplastic particles annually, compared to 4,000 particles annually for individuals drinking exclusively tap water.
Why it matters
This study provided one of the earliest quantitative benchmark estimates of human microplastic exposure through combined dietary, drinking water, and inhalation pathways, highlighting bottled water and air as major exposure vectors.
Limits
The dietary assessment accounted for only about 15% of total caloric intake, omitting major food groups due to lack of published contamination data. The estimates rely on heterogeneous sampling methodologies across 26 distinct studies, exhibit high variation, and do not establish whether ingested particles translate into toxicological absorption or adverse clinical health outcomes.
Cited by
- supports The average person inhales or ingests up to 120,000 microplastic particles per year from tap water, bottled water, and packaged foods.
- contradicts Drinking tap water alone can account for ingesting between 220,000 and 1.2 million microplastic particles per year.
- supports Individuals who drink bottled water exclusively consume up to 90,000 additional plastic particles per year compared to those drinking only tap water.