Plans to possibly cover the field at the Chicago's Sheridan Park with artificial turf have raised concerns with a national expert on turf-related problems from the University of Illinois at Chicago (UIC) School of Public Health, and counter-arguments from an artificial turf company spokesman.
"Right now, we are deciding whether the community prefers grass or artificial turf," said Larry Doody of the Sheridan Park Advisory Council.
A UIC expert is not a fan of artificial turf, however.
"We are worried about harmful chemicals," said Susan Buchanan, MD, MPH, associate director of the Great Lakes Center for Children's Environmental Health at the UIC School of Public Health. "Those can be heavy metals including lead, although most of the newer fields are made with lead-free materials, or they can be plasticizers like phthalates and polyaromatic hydrocarbons.
"Some of these chemicals are carcinogens. Some cause other chronic health effects when inhaled or ingested," she continued.
FieldTurf from Tarkett Sports is a brand being considered for Sheridan Park. It is made of a polyethylene/polypropylene fiber blend, silica sand, and ground styrene-butadiene rubber (SBR) infill. Darren Gill, director of marketing at Tarkett Sports said, "FieldTurf currently provides lead-free products. This statement can be confirmed via test results from independent laboratories. The safely of the FieldTurf product continues to be reaffirmed as FieldTurf's fibers have been proven to pose no harm to humans."
Gill said , "The plastic turf blades have the same makeup as shopping bags being used in your local grocery store. Everyone knows that SBR is in car tires, but it's actually used in foam mattresses, chewing gum, cosmetic sponges that women use, adhesive bandages, cleaning gloves used in the kitchen, water hoses, sports balls, and flip flops. People that are opposing rubber in the turf are actually using the same products daily. Silica sand is found in every beach."
Arguments over heat
Buchanan noted that artificial turf fields "act as heat sinks," she said. "They absorb heat, so very high temperatures have been measured on field surfaces during sunny weather."
Milone & MacBroom, a Connecticut engineering, landscape architecture, and environmental science firm, said in a study of thermal effects associated with artificial turf, "Maximum temperatures of approximately 156 degrees F" for the fibers "were noted when the fields were exposed to direct sunlight for a prolong period of time," and a maximum of 101 degrees for the rubber infill. They recommended wetting the turf, which provides "significant cooling."
Gill said , however, that the study also examined the heat levels two and five feet above both artificial turf and natural grass, the head and upper-torso levels of youngsters and adults. "and that's where they showed the difference in heat between the two is actually very marginal. The major concern here is heatstroke. When you look at heatstroke it's not much of a difference."
The study of the air above the field, Gill said, showed that "after three hours, the air above the natural grass surface was hotter than above artificial turf, and after seven hours the air above turf was 102 degrees and above the grass 99 degrees. Actually, the peak temperature was reached above the natural grass-just under 104 degrees."
Although modern synthetic turf fields are softer than older ones on which turf was placed over hard surfaces, Buchanan said there still is "a concern about increased musculoskeletal injuries like more ankle and knee sprains."
"There's also a concern about more skin abrasions, which may result in more secondary skin infections," she continued.
A study by Michael C. Meyers, PhD, of West Texas A&M University, and Bill S. Barnhill, MD, Panhandle Sports Medicine Associates of Texas, showed that athletes get injured on artificial and natural turf in different ways. They said there are more non-contact injuries, epidermal (skin) problems, muscle-related trauma, and injuries during higher temperatures on artificial turf, and more head and neural trauma, ligament injuries, and injuries taking longer to heal sustained on natural grass.