If you want to get a soccer mom’s attention, bring up the subject of artificial turf, the preferred playing surface for kids—or at least preferred by school boards and parks departments.
Reports of injuries and illnesses linked to turf, from concussions to cancer, are cause for alarm. And there is the further question of who is responsible for assuring the safety of these fields. Is it the Environmental Protection Agency? The Centers for Disease Control? The Consumer Product Safety Commission?
As an environmental health professor, and a soccer dad who watched my son play on these fields for years, I think it’s worth examining the facts and myths about turf fields, and consider potential hazards. Based on studies I have reviewed and conducted, I do believe there are potential health risks.
What Is Artificial Turf?
Artificial turf is made up of three major parts:
- The backing material that holds the individual blades of artificial grass in place.
- The plastic grass blades themselves.
- The infill—tiny black crumbs that help support the blades.
Various pigments are used to provide the green color of the blades. The white boundary lines can include lead or titanium, and still other metals are used for school logos on the field.
Those little black crumbs, made from tires, are the main problem; tires can be toxic. Modern tires are a mixture of natural and synthetic rubber, carbon black—a material made from petroleum—and other chemical compounds. Each tire contains 4 to 10 gallons of petroleum products. They also contain metals, including cadmium, lead (which is toxic to the nervous system), and zinc.
Some of the chemicals in tires, such as dibenzopyrenes, are known carcinogens. In addition to chemicals used in the manufacture of the tire, any chemical the tires were exposed to during their use can be absorbed by the carbon black.
Even though artificial turf does not have to be mowed, it turns out that crabgrass and other weeds can grow through it. To keep its finely manicured appearance, weedkillers need to be applied—a relatively common practice. A variety of health concerns have been linked to these products as well.
Other Health Concerns
Fields with artificial turf tend to get far hotter than grass fields. Field surface temperatures on artificial turf can reach as high as 200 degrees F. At these temperatures, even with athletic shoes on, children can get burned. It is rare, even on a very hot day, for natural grass to reach half the temperature of artificial.
While manufacturers recommend spraying artificial turf fields with water to keep the temperature down, the cooling effect can vanish in as little as 20 minutes.
Because it is laid over either concrete or compacted earth, artificial turf can be a harder surface than grass. This can increase the risk of injuries, particularly concussions, should a player take a tumble. The unit used to describe hardness is Gmax. The higher the Gmax number, the higher the likelihood of concussion. It is important to keep in mind that these numbers are highly dependent on the substrate, temperature, age, and maintenance of the field.
Can the Chemicals Harm Kids?
The key question on exposure is, do these chemicals get into children playing on these fields?
While it is true that the tire crumbs are large, it is easy to show that they don’t necessarily remain large over the life of the field. In a study in New Jersey, we employed a robot called PIPER (Pre-toddler Inhalable Particulate Environmental Robotic) to study if there were inhalable exposures from the artificial turf.
We showed that tiny particles from the turf can become suspended in the air above the field and then inhaled by children playing on it. What has become apparent is that microscopic particles of carbon black break off from the crumb rubber and are small enough to be inhaled. Additionally, the blades of grass can also break down into microscopic particles over years of exposure to sunlight and weather, forming a respirable dust.
How do these particles get into a child?
Think of the “Peanuts” comic strip character Pig-Pen, the kid always engulfed by a visible cloud. The truth is that all children—and people—have a cloud of microscopic particles around them. This personal microenvironment of dust particles, invisible to the naked eye, is just as real as Pig-Pen’s. These small particles and their chemicals can be inhaled or swallowed.
Do They Cause Illness?
A clear answer on whether artificial turf increases the risk of injury or illness is far more challenging. Let’s consider cancer and neurologic effects, the two major health-related concerns in regard to artificial turf.
The question of cancer and artificial turf gained significant national attention in the United States with a series of news stories on NBC Nightly News in October 2014 regarding a cluster of cancers in young female soccer players.
A cancer cluster is the appearance of an unusually high rate of cancer in one location during a particular time frame. The story, while dismissed by the turf industry, again resurfaced in 2015.
As many as 80 percent of suspected cancer clusters are determined not to be true increases in cancer cases and due only to random chance. The problem is, without detailed and often expensive scientific investigation, it can’t be determined whether it’s real.
Just recently, the Washington State Department of Health issued a report on its study of the reported cancer cluster in these soccer players. Their report found no evidence of a causal effect between people playing on artificial turf and developing cancers. As they acknowledge, that does not mean there is no risk, only that this study did not find one. The department also suggested that there is still room for a broader investigation on this question.
It is also worth considering the potential risk of the neurologic impairment from ingesting any lead present in the paint of the blades and the rubber infill in turf.
What’s the Bottom Line on Safety?
While the artificial turf industry says it’s safe, we know that tires contain established carcinogens. If we were to consider only what tires are made of, one would think they should be classified as hazardous waste, though the EPA currently classifies tires as municipal waste.
The EPA has been conducting research into the question of crumb rubber toxicity, but the jury is still out.
There is little question in the minds of many scientists that crumb rubber should not be a first choice material for children to play on. Parents should be able to enjoy watching their children playing sports—without worrying they are being put at risk.
Stuart Shalat, Professor and Director of the Division of Environmental Health, School of Public Health, Georgia State University. This article was originally published on The Conversation. Read the original article.