Hazardous compounds in recreational and urban recycled surfaces made from crumb rubber. Compliance with current regulation and future perspectives

Crumb rubber obtained from scrap tires is greatly employed for the construction of different facilities for sport, recreational and other uses. However, in recent years the concern about their safety and the related adult and children exposure to these surfaces is growing. This study aims a thorough chemical characterization encompassing 42 hazardous compounds, including polycyclic aromatic hydrocarbons (PAHs), phthalates, adipates, antioxidants and vulcanization agents in a wide range of crumb rubber from different surfaces. For the extraction of the target compounds, a method based on ultrasound-assisted extraction followed by gas chromatography-tandem mass spectrometry (UAE-GC-MS/MS) has been validated. Forty crumb rubber samples coming from synthetic turf football pitches, outdoor and indoor playgrounds, urban pavements, commercial tiles and granulates, and scrap tires, were analyzed. In addition, green alternative materials, such as sand and artificial turf based on cork granulate infill were included to compare the levels of the target compounds with those of crumb rubber. Most of the analyzed recycled surfaces meet the recent limits proposed by the European Commission for rubber granulates and mulches, although they exceed in several cases the maximum levels allowed for rubber consumer products. Besides, most of the other target compounds, including several of them considered as endocrine disruptors, were detected in the analyzed samples, reaching parts per million concentrations.