Children's playgrounds contain more microplastics than other areas in urban parks

Children spend many hours in urban parks and playgrounds, where the tree canopy could filter microplastics released from the surrounding urban hotspots. However, the majority of children's playgrounds also contain plastic structures that could potentially release microplastics. To assess if the children's playgrounds pose a higher exposure risk than other places inside the park, we evaluate the extent of microplastic contamination in the sand, soil, and leaf samples from 19 playgrounds inside urban parks in Los Angeles, CA, USA. The average microplastic concentration in sand samples collected inside the playground was 72 p g-1, and >50 % of identified plastics were either polyethylene or polypropylene. Microplastic concentrations inside the playgrounds were on average >5 times greater than concentrations outside the playgrounds in the park, indicating that children playing within the playground may be exposed to more microplastics than children playing outside the playground in the same park. By comparing the microplastic composition found inside and outside the playgrounds with the plastic composition of the plastic structures in the playground, we show that plastic structures and other products used inside the playgrounds could contribute to elevated microplastic concentration. The population density was slightly correlated with a microplastic concentration in the park soil but did not correlate with microplastic concentration inside the playgrounds. Therefore, playgrounds in urban parks may have microplastic exposure risks via inhalation or ingestion via hand-to-mouth transfer.