Plastic signatures in childhood: first evidence of urinary micro- and nanoplastics in primary school children from Cyprus

Background: Microplastics (MPs) and nanoplastics (NPs) have recently been detected in several human biological matrices; however, evidence in children remains limited. This exploratory study aimed to investigate the presence and concentration of urinary MPs and NPs (MNPs) in primary school children residing in Cyprus. Results: First-morning urine samples from 29 children were analyzed using scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM/EDX), applying strict contamination-control measures and focusing on particles < 10 μm. Pyrolysis–GC/MS was additionally used to characterize polymer composition, identifying polyethylene (PE) and polypropylene (PP) as the predominant polymers. MNPs < 10 μm were detected in all samples, with concentrations ranging from 393 to 8050 particles/ml (median: 1217 particles/ml; IQR: 800–2030). Particle diameters ranged from 0.88 μm to 3.44 μm (median: 1.69 μm; IQR: 1.25–2.25 μm; minimum: 0.77 μm; maximum: 4.88 μm). No statistically significant associations were observed between MNP concentrations and body mass index (BMI)-for-age categories or hand-to-mouth behavior. Conclusions: Although direct comparisons with previous studies are limited due to methodological variability among studies and the lack of standardized protocols for MNP quantification in human urine, these findings provide preliminary evidence of urinary MNPs in children. Further large-scale studies using harmonized analytical approaches are needed to better characterize exposure patterns in pediatric populations.