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Sports and recreational activity promote healthy physical well-being. But what if the sports field and playground that are made of a rubber base (comprising crumb rubber from recycled tyres) become potential lair for danger, asks Angelica Buan in this report.
The terms “artificial turf” and “crumb rubber” are currently being frequently mentioned over the news, but not quite in a positive way. Circumstances have been linking these materials, used in sports fields and playgrounds to a host of potential safety risks, including injuries and cancer.
Artificial turf is synthetic-fibre-based surface that mimics the look of natural grass and is often used in a sports arena or in playgrounds and even in residential lawns. It is preferred mainly for its lower maintenance, requiring no irrigation or trimming and weeding, compared to having grounds with real grass. At the same time, artificial turfs are durable for heavy use. Covered recreation areas can also make use of artificial turfs where absence of sunlight cannot grow healthy grass.
Artificial turfs have been around since the 1960s, and have evolved to third generation (3G) turf systems, which are widely used today.
The 3G turfs have been improved to offer low impact and softer feel. They consist of a pile (or the artificial grass blades) of up to more or less 60 mm height, placed atop a base layer of sand and infill of crumb rubber (from recycled tyres).
Hidden costs make them expensive
Contrary to the low cost linked to artificial turfs, these are now found to be far from being less expensive, according to the University of Arkansas (UA) Division of Agriculture website.
It said that the turfs periodically require additional infill; irrigation during high temperatures on warm days; chemical disinfectants; sprays to reduce static cling and odours; drainage repair and maintenance; erasing and repainting temporary lines; and discarding of organic matter accumulation.
UA also mentions that the longer term cost of synthetic turf field is higher compared to a natural turf field; not to mention the disposal costs that would be incurred by a synthetic turf field, with the crumb rubber component.
“When artificial turf needs renovating every 8-10 years, there is a hidden cost of disposal. Because the field is filled and top-dressed with a crumb rubber material (typically made from ground automobile tyres), the material may require special disposal,” it said.
Drawback on safety
Comprising rubber pellets, the concern on them is that they are laden with carcinogenic and toxic chemicals, including benzothiazole, carbon black, and heavy metals, which render them even unsuitable for landfills. They may also be potentially hazardous when accidentally ingested, inhaled, or if a user comes into contact with them.
Notwithstanding that these materials can leach into groundwater and are prone to temperature build up on warm days, unlike real grass, which is designed by nature to stay cool on hot days through soil moisture evaporation.
In a study by researchers at Brigham Young University, it found that fields containing crumb rubber often reach unsafe surface temperatures, averaging 47.2°C, with a daily high of 69.4°C.
Meanwhile, artificial turfs have also been accounted for diseases inflicted on users. A report on cases say that antibiotic-resistant infection, Methicillin-resistant Staphylococcus aureus (MRSA) from 2003 to 2005 involved 276 football players in Texas, or a rate of 32 for the general population of 100,000, according to the US Centre for Disease Control and Prevention. While there has been lack of data to establish the rubber-base turfs with the prevalence of infection, findings show that infections often occur at the site burn and are misdiagnosed.
Incidences of blood cancer cases have also been reported among contact sports players. Since 2009, after learning about two goal keepers contracting cancers, associate head coach of the University of Washington, Amy Griffin, rounded up a list of players stricken with leukaemia, lymphoma and other blood cancers. She found that there were 38 US soccer players with blood cancers, including 34 goalkeepers. According to her, the one thing in common shared by these players was that they often played on artificial turf made with crumb rubber.
Connecting the dots
Studies are ongoing to establish the link between exposure to rubber in artificial turfs and cancer; and opinions are mixed on what some experts say are “anecdotal evidences” thrown against the turfs.
These include a 2013 study published in the scientific journal Chemosphere, which revealed elevated levels of toxic substances on surfaces containing recycled tyre rubber.
Other studies, meanwhile, suggested that the crumb rubber do not pose significant risks. In 2009, the US Environmental Protection Agency (EPA) study suggested that concentrations of crumb rubber in turfs monitored in the study were below levels of concern.
The study also found that levels of air samples measured for particles, metals and volatile organic compound concentrations in the monitored turf fields and areas away from these fields (background levels), were the same.
Moreover, there were no tyre-related fibres observed in the air samples. As well, more than 90% of the lead in the tyre crumb was tightly bound and unavailable for absorption by users of the turf fields; and the levels of zinc, a tyre additive, were also below levels of concern, according to the EPA report.
However, as health concerns mount, especially that which associate crumb rubber in field turfs to cancer, EPA is reportedly taking a softer stance on promoting crumb rubber, being a recycled tyre by-product, which the agency has been vested to do since the early 1990s to reduce the US’s scrap tyre stockpile.
It also clarified that its earlier 2009 crumb rubber safety levels study was limited in scope, hence, inconclusive. It said that more testing on crumb rubber should be carried out; and using rubber crumbs will remain a prerogative of a state or local agencies.
Safer organic alternative
The use of natural fibres, albeit at a higher cost, such as coconut husks, cork and old shoes, are some of the materials being eyed to replace crumb rubber as infill in turf fields.
Some schools in the US are already either replacing the rubberised turfs with or implementing organic turf fields.
Although the crumb rubber infill turfs may be around for a while in some places, this new study could pave the way for new solutions to make the rubber base turfs more “safe”.
According to a study by the Pacific Northwest Pollution Prevention Resource Centre (PPRC), the ultraviolet C (UVC) light can effectively disinfect artificial turfs against antibiotic-resistant MRSA and other infections. The method employs the C-band, a shorter wavelength of UV light that kills germs. The study suggested that UVC treatment, when properly administered to the artificial turf surface, is an effective, eco-friendly method to eliminate the disease-causing organisms.
The UV light, also known as ultraviolet germicidal irradiation, which is also effective in eliminating bacteria in food, water, air, and various surfaces, attacks toxins by rupturing the nucleic acids of micro-organisms, rendering bacteria inactive.
The rate of success depends on certain factors such as application time on the surface; beam strength and use over time positioning relative to the treated surface. Another advantage of using UVC is that the process releases no harmful toxins onto the field or surrounding areas, the study stated.