Scientists have found that microplastics are present in the urine of most school-aged children, according to a study published in Environment International. The research involved 1,308 ten-year-old participants from the Ma’anshan Birth Cohort between January 2024 and 2025. Researchers identified 19 different types of microplastics (MPs) in over 91% of the samples, with a median concentration of 250 particles per milliliter.
The study used LDIR spectroscopic imaging to detect MPs and classified them by size. Most detected particles were small, which may be more likely to cross biological barriers within the body. PTFE, a polymer commonly found in non-stick cookware, was the most abundant type found.
Researchers took steps to avoid contamination during sample collection and analysis by using glass containers instead of plastic and cleaning equipment thoroughly. Laboratory staff wore protective clothing and masks throughout the process.
Children’s dietary patterns were assessed using the Mediterranean Diet Quality Index for Children and Adolescents (KIDMED). The researchers then examined how adherence to this diet related to microplastic exposure using statistical models that accounted for factors such as maternal age, education level, household income, residential area, and child age and sex.
The findings showed that children who adhered more closely to the Mediterranean diet had different patterns of microplastic exposure compared to those with lower adherence. Specifically, higher KIDMED scores were linked with a greater likelihood of having no detectable levels of certain polymers—EVA, PVA, and PLA—in their urine. At the same time, higher scores were associated with increased levels of PA but decreased concentrations of PTFE among those who did have detectable amounts. There was no significant association between overall microplastic abundance or particle size and KIDMED scores.
"Stronger adherence to the MedDiet was associated with distinct patterns of MP exposure," according to the study authors. "Dietary habits may influence exposure levels."
Despite these associations, researchers noted several limitations. Because this was a cross-sectional study—meaning it looked at data from one point in time—it cannot prove that dietary habits cause changes in microplastic exposure. Also, since most participants lived in urban areas, results may not reflect rural populations.
Microplastics are defined as plastic particles ranging from 0.1 to 5,000 micrometers in diameter and are considered widespread environmental contaminants found in air, soil, water—and increasingly—in food and bottled drinks. Previous research has focused mainly on adults; however, children might be at greater risk due to varied diets and frequent contact with packaged foods.
The authors call for future research using longitudinal designs or interventions to better understand how diet affects microplastic accumulation over time.
