Influence of park characteristics and urbanization on culturable bacterial and fungal abundance in dust from children’s playgrounds in Tehran’s urban parks

Urban parks provide children with essential microbial interaction situations, increasing anthropogenic forces may change the abundance of culturable microorganisms in playground dust. Using culture-based enumeration, this study measured culturable bacteria and fungus in settled dust from kids’ playgrounds in 68 urban parks in Tehran in July and August of 2023. Significant variation in abundance was explained by several linear regression models with continuous predictors (adjusted R² = 0.78 for bacteria, p < 0.001; adjusted R² = 0.75 for fungi, p < 0.001). The strongest positive predictors were larger parks (standardized β = 0.42, p < 0.001 for bacteria; β = 0.31, p = 0.008 for fungi) and higher tree densities (β = 0.25, p = 0.002 for bacteria; β = 0.18, p = 0.040 for fungi). While proximity to commercial centers had a negative impact on cultivable bacterial abundance (β = -0.19, p = 0.024), population density had the biggest negative effect (β = -0.16, p = 0.060 for bacteria; β = -0.29, p < 0.001 for fungi). With bacteria exhibiting more resilience than fungus, these trends suggest that park design can lessen the suppressive impacts of urbanization on microbial ecosystems. The results highlight the possibility of optimized park layout to preserve microbial abundance in playground dust, supporting ecosystem services in dry megacities (UN Sustainable Development Goals 3, 11, and 15).