Emissions of > 1 mm rubber granule infill from artificial turfs: a case study from two football pitches

Abstract Background Artificial turf pitches are considered a major source of microplastics, especially rubber granules; however, field data on emissions remain scarce compared to theoretical estimates. This study investigated rubber granule infill emissions from two football pitches in Helsinki, southern Finland, by combining field measurements with hydrological modelling. Field samples for estimating rubber granule (> 1 mm) emissions were collected from soil, stormwater, snow and pitch maintenance equipment to identify key emission pathways. In addition, the attachment of rubber granules to footwear during exercise was studied. Hydrological stormwater modelling was used to assess the dynamics of surface runoff and granule transport. Results The study demonstrated differences between the two studied pitches, as well as among areas within the pitches, in terms of rubber granule (> 1 mm) emissions to soil and the relative importance of the examined emission pathways. The results revealed high variability between the two sites, with annual rubber granule infill accumulation on a single plot (0.04 m 2 ) ranging, on average from 23 to 886 g (dry weight). Separating the effects of individual factors contributing to the observed emission loads was not always possible, as multiple variables, such as pitch usage, maintenance practices and weather conditions simultaneously influenced rubber granule emissions. Conclusion The study concludes that once rubber granules (> 1 mm) enter stormwater systems, they can be transported relatively freely to receiving water bodies. This highlights the importance of tailored stormwater and other management strategies at the studied pitches to minimize rubber granule emissions.