Factors affecting microplastic pollution of sandboxes in urban residential areas: Simple methodology for quality control in the context of potential exposure assessment for children.

This article focuses on the occurrence and distribution of microplastics in urban sandboxes, which are common playground features for children, and assesses the potential exposure risks. A study conducted in three residential estates in Kielce, Poland, found microplastics in all 27 sand samples collected from nine sandboxes, with concentrations ranging from 60 to 5,540 items per kilogram of sand. The most prevalent microplastics were fibers and fragments, particularly transparent fibers and red fragments, and a strong positive correlation was observed between microplastic abundance and the elevation of the sandboxes, suggesting atmospheric transport as a key factor. Based on estimated soil ingestion rates by children, the study indicates that sandbox play could lead to the ingestion of over 1,000 microplastic particles daily in worst-case scenarios, highlighting the need for regular sandbox maintenance and further research on health impacts and seasonal variability.