Artificial turf systems have traditionally been evaluated based on performance criteria such as shock absorption, energy restitution, durability and player comfort. However, environmental considerations are becoming increasingly relevant in the decision-making process for sports facility owners, municipalities, universities and professional sports organizations.

Among these considerations, the composition of infill materials is receiving growing attention.

A study published in Science of the Total Environment evaluated 91 synthetic turf football fields across 17 countries and assessed the presence of various chemical compounds in different infill materials. The research analysed 78 recycled tire crumb rubber samples and compared them with alternative infill materials including cork, thermoplastic elastomers and coconut fibre.

Understanding What Researchers Found

The study identified several groups of compounds in recycled tire crumb rubber samples collected worldwide, including polycyclic aromatic hydrocarbons (PAHs), plasticizers, antioxidants and vulcanization additives.

According to the authors, hazardous compounds were found in crumb rubber samples from all regions analysed. Some samples contained substances classified as carcinogenic, endocrine-disrupting or potentially harmful to aquatic environments. The researchers also noted that recycled tire rubber and plastic infills are considered microplastics, which may persist in the environment for long periods of time.

The study further highlights that several previous investigations have demonstrated the potential migration of compounds from infill materials into runoff water, air and surrounding environments. These findings have contributed to growing interest in understanding how material selection may influence the overall environmental profile of artificial turf systems.

Cork as an Alternative Material

Alongside crumb rubber, the study also analysed cork-based infills.

The researchers reported that cork samples contained significantly lower concentrations of the compounds investigated when compared with recycled tire rubber. In their conclusions, the authors state that cork appears to be an adequate alternative while noting that some plastic-based alternatives contained elevated concentrations of plasticizers.

The authors also suggest that trace levels detected in some cork samples may be explained by residual contamination from previous infill systems rather than the cork material itself. These findings contribute to a growing body of research exploring how different infill materials may influence the environmental profile of sports surfaces.

Water Quality Is Becoming a Design Consideration

Beyond the scientific literature, environmental considerations are increasingly influencing real-world sports infrastructure projects.

One example is the Seattle Sounders FC Providence Swedish Performance Center & Clubhouse in Washington State. The facility achieved Salmon-Safe certification, a program focused on protecting water quality and aquatic ecosystems through responsible land management practices.

As part of the project, cork-based infill was selected to support the facility's broader environmental objectives, including stormwater management and watershed protection.

The project reflects a broader trend in which sports organizations are evaluating facilities not only through the lens of athletic performance, but also through their interaction with surrounding ecosystems and water resources.

The Growing Importance of Material Composition

Performance remains a fundamental requirement for any artificial turf system. However, scientific research and real-world projects increasingly show that material composition is also becoming part of the evaluation process.

As interest grows in topics such as water quality, stormwater management and microplastic emissions, the characteristics of the materials used within a sports surface are receiving greater attention from researchers, facility owners and sports organizations alike.

The growing adoption of alternative infill materials reflects this broader evolution in how artificial turf systems are assessed and specified.

While performance remains at the core of every sports surface, the conversation is expanding. Material composition, environmental interaction and long-term impact are increasingly being considered alongside traditional performance metrics.

As the industry continues to evolve, understanding the role of infill materials will be essential for stakeholders seeking to balance athletic performance with broader environmental objectives.