in NEWSMEMBER EXCLUSIVE
The American soccer team undergoes training at a facility in Irvine on June 10. FIFA, the governing body of the World Cup, has mandated that matches are not played on artificial turf, citing concerns about an increased likelihood of injuries. Additionally, some within the athletic community have voiced apprehension regarding potential chemical exposure from synthetic surfaces.(Image credit: Jamie Squire via Getty Images)Share this article 0Join the conversationFollow usAdd us as a preferred source on GoogleSubscribe to our newsletter
When the U.S. national team competes against Paraguay in the World Cup at Los Angeles’ SoFi Stadium on June 12, the athletes will play on a natural-grass field. This field, just a month prior, featured a meticulously constructed hybrid surface laid over an existing artificial-turf base. This installation was part of a larger initiative undertaken in anticipation of the World Cup, aiming to ensure that the world’s premier soccer teams compete on primarily natural-grass playing grounds.
FIFA, the organization that presides over the World Cup, has for years prohibited the use of synthetic turf in its tournaments. This ban stems primarily from well-documented concerns about an elevated risk of player injuries. Synthetic turf is also known to cause severe friction burns due to its poor heat dissipation, which can lead to surface temperatures reaching up to 200 degrees Fahrenheit (93 degrees Celsius).
Nonetheless, many individuals within the broader sports community harbor concerns that synthetic turf may present more subtle dangers, such as elevated exposure to heavy metals, carcinogenic compounds, and microplastics.
A hybrid turf field was put in place at New York New Jersey Stadium in preparation for the World Cup final scheduled here in July. FIFA has stipulated that all World Cup matches must be contested on a natural grass surface, although concerns about chemical exposure were not a primary driver of this directive.
(Image credit: CHARLY TRIBALLEAU via Getty Images)
A recent decade-long study conducted in California indicated no significant health risks associated with the chemicals found in artificial turf. However, experts remain unconvinced that this study has definitively addressed the concerns surrounding artificial turf. Here’s why.
Wonder of the Space Age
In the 1960s, artificial turf was hailed as a marvel of the Space Age, a sentiment echoed in its brand name, AstroTurf.
“A vacuum and broom are the only necessary maintenance items,” an article from around the time of a 1966 Houston Astros-Los Angeles Dodgers game observed. The initial generation of turf used on the field was a coarse nylon carpet. However, in the 1970s, it was supplanted by “2G” turf, which featured a slightly less abrasive polyethylene-fiber carpet surface atop a cushioning layer of sand.
The most recent iteration, known as 3G, offers enhanced traction and shock absorption. This is typically achieved using infill composed of shredded recycled tires, which are treated with various additives to prevent degradation and improve durability.
Rolls of synthetic turf. The majority of modern turf utilizes infill made from ground tire fragments. This infill is central to the ongoing discussion about the safety of artificial playing surfaces.
(Image credit: Karl-Hendrik Tittel via Getty Images)
This infill material is at the core of the matter. All these tire fragments contain hundreds of chemical compounds, creating “an exposure scenario that had never existed before,” Rachel Massey, an environmental health researcher at the University of Massachusetts Lowell Center for Sustainable Production, informed Live Science.
Over 95% of the approximately 18,000 to 19,000 turf fields in the U.S. currently incorporate tire-crumb infill. AstroTurf has maintained its prominent position, offering 3G products. (Live Science attempted to contact AstroTurf for comments regarding their products but received no response.)
Harmful chemicals?
Certain researchers express concern that turf contains close to 400 chemicals that have been associated with various health issues, ranging from asthma to leukemia.
“None of those [risk assessment] studies dispute the fact” that these chemicals are present, Massey stated. “So then all the debate is about exactly how much exposure there is.”
To determine whether such exposure reached detrimental levels, the California Office of Environmental Health Hazard Assessment (OEHHA), a branch of the California Environmental Protection Agency, conducted a study examining the health impacts of chemical exposure from synthetic turf.
“We identified as many chemicals as we could in the crumb rubber by doing non-targeted sampling and assessed as many chemicals as we could,” explained Amy Gilson, a spokesperson for the OEHHA.
They endeavored to quantify exposure to metals commonly found in turf infill, including lead, cadmium, manganese, and zinc. Zinc was detected most frequently at levels exceeding U.S. regulatory guidelines. While zinc is an essential nutrient for the human body, excessive amounts can be harmful, potentially leading to anemia, pancreatic damage, and reduced fertility.
Additionally, they investigated carbon black, a filler material used in tires known to cause cell death in laboratory settings; benzene, which has been linked to several forms of leukemia; toluene, which is toxic to the nervous system, liver, and kidneys; and polycyclic aromatic hydrocarbons, compounds typically found in tobacco and wood smoke that have been associated with cancer in animal studies.
A recent California investigation examined exposure levels to numerous chemicals present in the infill used for artificial turf fields. A significant portion of this infill is derived from discarded automobile tires.
(Image credit: Maxshot/Getty Images)
Another potential concern arose last year when 1,3-dimethylbutylamine (1,3-DMBA), a stimulant prohibited by the World Anti-Doping Agency, was detected in post-game samples from eight female professional soccer players from opposing teams. The artificial turf was identified as the source of the banned substance. During tire wear, 6PPD—a substance frequently added to tires to mitigate ozone depletion—can break down into 1,3-DMBA, which was found on the turf where the match took place.
The California EPA report also investigated the presence of microplastics within turf.
In 2023, the European Union declared a ban on the sale of products containing intentionally added microplastics, set to take effect in 2031. Specifically, the granular infill used in artificial turf was identified as “the largest source of intentional microplastics in the environment.” The United States currently lacks comparable legislation.
Microplastics may pose a threat to human health by accumulating in various bodily tissues through ingestion, dermal contact, or inhalation.
Preliminary research conducted on human cells in laboratory settings suggests that microplastics could damage the lining of blood vessels and encourage the development of atherosclerotic plaques and blood clots. Other studies have proposed potential connections between microplastic exposure and conditions such as asthma and inflammatory bowel disease. However, significant uncertainty remains regarding the methods used to measure microplastic exposure and whether such exposure is a direct cause of disease or merely an indicator of other factors contributing to these conditions.
“Negligible” long-term harm
The California EPA concentrated its efforts on chemicals within tire infill that could potentially inflict harm at high concentrations. Subsequently, it estimated exposure levels for players, referees, and spectators who came into direct contact with, inhaled, or inadvertently ingested tire crumbs. Initially, exposure was estimated indirectly by observing individuals.
“We actually had teams of people going out and videotaping players on the field,” Gilson remarked.
The research team also gathered samples of artificial turf, subjected them to synthetic bodily fluids like sweat, saliva, and intestinal fluid in laboratory conditions, and then measured the concentrations of numerous potentially harmful chemicals within these fluids. To adopt a more cautious approach, they presumed that every chemical detected in their experiments would be fully absorbed by human cells, Jocelyn Claude, a toxicologist at the OEHHA involved in the study, explained to Live Science.
The study concluded that there were “no acute risks,” indicating that short-term exposure to these substances is unlikely to cause immediate harm. Furthermore, the risks associated with longer-term health effects, such as cancer or reproductive issues, were deemed “negligible.”
However, some experts have raised concerns about the study’s methodology. Andrew Watterson, a professor emeritus of public health at the University of Stirling in the UK, suggested that the study should have collected urine or exhaled air samples directly from individuals exposed to artificial turf, rather than estimating exposure through synthetic bodily fluids.
Wrong approach to risk assessment
For Massey and several environmental researchers interviewed by Live Science, the primary issue lies in the flawed underlying approach used by the California study—and most other environmental assessments conducted in the U.S.
Instead of questioning whether an average person is at risk, society should strive to minimize exposure across the entire population, thereby also protecting those who are more vulnerable. Rather than asking, “Is this risk acceptable?” the alternative approach seeks to answer, “How can we create the healthiest and safest playing surface for a child?” Massey elaborated.
The California report included referees and spectators in its scope, in addition to players. However, it might have overlooked other potentially at-risk groups, such as individuals exposed to chemicals that have leached into the water supply from synthetic turf, according to Tracy Stewart, a resident of Medway, Massachusetts, who advocates against the use of artificial turf.
Another byproduct of 6PPD, the chemical linked to doping, has been shown to cause mass mortality events in coho salmon. Consequently, when dead salmon began appearing near an artificial turf field in Vancouver where scientists had detected 6PPD-Q and a range of other chemicals in the stormwater runoff, the local community became concerned.
The California study estimated 6PPD-Q exposure levels in synthetic bodily fluids but did not model potential impacts on groundwater. Furthermore, without established safe limits for this chemical, the California study was unable to assess the risks it may pose.
Beyond 3G turf
The primary appeal of synthetic turf lies in its “increased hours of use,” according to Garnet Brownbill, a spokesperson for the Natural Turf Alliance, a non-profit organization promoting alternatives to synthetic turf throughout Australia. “It’s not impacted by the weather, it never closes, and people claim it’s maintenance-free—which it isn’t, by the way,” he told Live Science.
However, in light of the impending EU ban on microplastics in infill, numerous scientists are developing alternative materials that can offer similar advantages.
The turf being installed at the New York New Jersey Stadium. This type of hybrid turf consists of 99.5% grass and 0.5% stitching material.
(Image credit: CHARLY TRIBALLEAU via Getty Images)
One material currently under development is hybrid turf, featuring a surface composed of “99.5% natural grass,” supplemented by 0.5% stitching material made from either plastic or a biodegradable polymer, stated Aaron Golembiewski, head of business development at Turftalents, a firm that advised FIFA on the installation of hybrid turf at several U.S. stadiums. Hybrid turf is “stronger than if it’s grass alone,” Golembiewski told Live Science, as it “increases [the] quantity of play.”
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It also offers a smoother playing surface compared to standard grass fields, which naturally have undulations and divots. He noted that hybrid turf is more economical to install from scratch than synthetic turf and has a longer lifespan, though it requires more intensive upkeep.
Natural grass fields may prove adequate for numerous communities. While some stakeholders are exploring methods for more sustainable grass maintenance, other researchers are focused on enhancing grass varieties. “If the same amount of engineering went into natural grass, there’s all of this stuff that we can do,” Brownbill commented. Not all types of grass are created equal.
“There are high-heat-resilient grasses; there are shade-resilient grasses; there are high-wear grasses,” Brownbill explained. “Municipalities are basically using 100-year-old technology… the same grass cultivars that existed 100 years ago.”
Editor’s Note: This article was created as part of the Dalla Lana Fellowship in Journalism and Health Impact program at the University of Toronto.
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