b'SENSE, NONSENSE AND SCIENCEBY: JOE SCHWARCZTHE TURF MAY BE ARTIFICIAL, BUT THE ISSUES ARE REALT he Euro 2020 tournament provided us with some excellent soccer matches, all played on natural grass. However, sometimes the simmering controversy about the safety of playing on artificial turf comes to a boil. Thats an apt term because these surfaces heat up in the sun much more than natural grass and players complain of greater risk of heat exhaustion. They also complain of carpet burns and blisters on the feet. But the bigger concern is potential toxicity. The first synthetic playing surface was developed by Monsanto in the 1960s. Named ChemGrass, at a time when it was still acceptable to use a chemical connec-tion in a positive way, it was made by melt-ing together nylon pellets and a pigment, and then extruding the hot mix through spinnerets to produce ribbons which could be woven into a fabric. It was durabledants and butadiene and styrene residuesinteresting? enough but falling on it was no fun evenfrom the synthetic rubber component.Given that the sporting landscape is though the nylon carpet was supported byMany of these are known, probable or pos- dotted with artificial turf, and that thou-a soft foam layer of polyurethane. When itsible carcinogens. Carbon black, used as asands and thousands of children, who are was installed in Houstons Astrodome asreinforcing filler, can harbour nanopar- more prone to the effects of toxins, play AstroTurf, ballplayers had to add carpetticles which some researchers claim areon such surfaces, further investigation is burn and turf toe to their vocabulary.carcinogenic and can penetrate cells, evenin order. Solid epidemiological data are Field Turf, a Canadian companyfinding their way to the brain. Lead-basedneeded to determine if there is indeed took the complaints to heart and came uppigments now phased out, but once used toa link between artificial turf and cancer with an improved version. Out went thecolour the grass, are another worry. Thereincidence, and we need experimental data stiff nylon fibres, in came soft, elastic pol- is also concern that dust from the rubberabout the extent and effects of exposure. yethylene fibres lubricated with siliconepellets can trigger allergies and asthma. The latter can be addressed by sampling oil. These were tufted into a rubberizedOf course, the major question isthe air above artificial fields for chemi-plastic mat, just like a giant shag rug. Theextent of exposure. That can come fromcals wafting out and by immersing sam-tour de force, though, was the infillthe inhalation of volatiles or dust releasedples of turf in fluids that simulate sweat, composed of sand and granules of crumbas the crumb rubber crumbles furtherlung mucus and digestive juices. So far, rubber which kept the fibres upright andunder stress. There is also the possibil- the few experiments that have been car-provided shock absorbency. Old rubberity of swallowing any particles that areried out along these lines found that the tires and athletic shoe soles were frozenkicked up by action on the field, a specialchemicals detected were below what is and ground up to make the pellets thatconcern to goalkeepers who often dive toconsidered to be hazardous, but there is would eventually become the subject ofmake a save and end up stirring up thegreat variation between turfs produced heated debate.rubber pellets. Can this be of any conse- by different companies, so that small The issue is that tires are made of aquence? A preliminary collection of datasurveys cannot yield conclusive results. mix of natural and synthetic rubbers andby a soccer coach in the US suggests anFurthermore, such studies do not address contain an incredibly complex array ofunusual number of cancer cases amongthe possible cumulative effect that may chemicals ranging from natural contam- athletes who have spent a lot of timebe proportional to the time spent playing inants such as lead to zinc oxide used inplaying on artificial surfaces, and in theon artificial turf.the vulcanization process and polycycliccase of soccer, a greater incidence amongAt this point it is impossible to quan-aromatic hydrocarbons in the oil blendedgoalkeepers than other players. So fartify the toxicological risk, if any, of playing with the rubber to provide proper texture.this evidence is anecdotal, but scienceon artificial turf that may look like grass, There are vulcanization accelerators likeoften starts with someone noting such aand even feel like grass, but doesnt behave benzothiazole, amines added as antioxi- relationship and saying, hmmm, isnt thatlike grass. 38IEUROPEAN SEEDIEUROPEAN-SEED.COM'