Playground microbes: A microbiological assessment of the contamination of water and soil-cover materials in public playgrounds in Hanover, Germany

While playgrounds support children's development, they can pose microbial health risks. This study assessed contamination in three Hanover playgrounds during summer 2024. Samples from puddles and soil-covers (sand and wood-chips) were tested for faecal indicator bacteria (FIB, Escherichia coli, and enterococci) and Legionella species. The median E. coli concentration was lower than that of enterococci across both soil materials, with both bacteria showing higher median levels in wood-chips compared with sand. Moreover, both FIB concentrations were higher on rainy days than dry days. Legionella spp. were found in nearly all wood-chip samples and some sand samples. Similar concentrations of E. coli and enterococci were seen in puddles from both rainwater and tap water, often exceeding European Bathing Water Directive thresholds. The Wakitu playground is likely the most contaminated, due to numerous visiting families and proximity to a city forest. This study highlights the need for microbiological monitoring of soil-cover materials and water to ensure playground safety and calls for stricter regulations to protect children's health in public spaces.