Synthetic Turf: Its Potential Impact on Children

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Synthetic Turf: Its Potential Impact on Children

Testimony: NY City Council Parks Committee, Dec. 13, 2007

William Crain

Across the country, schools, parks, and private sports facilities are installing the “new generation” synthetic turf. It is springier than the old AstroTurf and has appealing advantages over natural grass. It doesn’t get muddy during the rain or torn up by players’ cleats, so it permits teams to fit more games and practices into their schedules. New York City is among the leaders in the installation of the new synthetic turf, often replacing natural soil and grass fields.

But as a developmental psychologist, I am concerned about it.

Today’s children largely grow up in synthetic, indoor environments—doing homework, watching TV, playing video games, surfing the Internet. They have little contact with soil, grass, trees, wind, and birdsong. Two nationwide surveys have found that 6- to 12-year-olds spend an average of less than one hour a week in free outdoor play [1]. When children do get outdoors, they often play organized sports. Until recently, sports at least gave children some experience with nature. But now, with the growing popularity of synthetic turf fields, their experience with nature will be less than ever.

Children’s increasing isolation from nature is a serious problem. A growing body of research suggests that children need contact with nature to fully develop their cognitive and emotional capacities.

Benefits of the natural environment for psychological development

Specifically, contact with nature benefits children in three ways [2] .

1. Nature stimulates children’s powers of patient observation. Toddlers, for

example, spend hours at the beach investigating sand. They explore it with intense concentration. When older children are given time to play in parks, weedy vacant lots, or woods, they often spend long stretches of time observing birds, plants, insects.

Children’s lack of time in natural settings might contribute to the attention deficits so common today. Studies by Andrea Taylor and others [2] suggest that contact with even sparse nature—just some grass and vegetation—increases children’s attention spans.

2. Nature stimulates children’s creativity. In natural settings, children love to

build things, such as shelters and hideouts beneath trees . Nature inspires many themes in children’s drawings, which frequently include clouds, grass, trees, birds, and flowers. Nature also inspires much of the poetry children create.

3. Natural settings give children feelings of peace and being at one with

the larger web of life. As environmental researcher Louise Chawla points out, such experiences are often described in adult autobiographies. For example, the African American minister Howard Thurman described his boyhood feelings of unity with the woods, the night, and the sea in Florida . Such feelings, he said, gave “me a certain overriding immunity against much of the pain with which I would have to deal in the years ahead when the ocean was only a memory. The sense held: I felt rooted in life, in nature, in existence [2]”

Of course, grass playing fields only expose children to nature to a limited degree. They do not compare to woods or the ocean. But even grass playing fields can stimulate children’s senses, especially when adults give children time to play on them in their own ways. After informal games, youngsters often relax on a field and examine blades of grass, weeds, and dirt. They listen to the wind, feel the sun’s warmth, and watch birds, insects, and butterflies.

And their imaginations stir. Children sometimes look up at clouds and sky and ponder questions such as where the universe ends, and what’s behind the sky. One girl told me she likes to toss blades of grass into the air and imagine that they are “grass angels.” The research of Andrea Taylor and others [2] suggests that even sparse greenery stimulates more creative fantasy play among inner-city children than barren environments.

Because I believe children benefit from rich contact with nature, I was distressed in 2004 to learn about the New York City Park Department’s plan to replace four acres of natural soil and grass fields in Riverside Park with synthetic turf. I asked several local residents (including members of the West Side Green Party) to help try to get the Parks Department to change its mind. We wrote letters to the Parks Department and public officials, held forums and rallies, and gathered over 600 signatures on a petition. But we couldn’t stop the installation of the artificial turf.

Potentially Hazardous Chemicals

When, in the spring of 2006, I visited Riverside Park’s new synthetic fields, I was surprised to see large clusters of rubber granules. I had known that the granules were an important component of the new turf, contributing to its resiliency. I also had known that the granules typically come from recycled rubber tires and might contain toxic chemicals. But I had assumed that the granules were at the base of the turf. I hadn’t known that they are so prevalent on the surface, and that children and athletes come into frequent contact with them. As I picked up a handful, a boy came over and said, “I get them in my shoes and they come out when I take them off at night.”

I therefore asked Professor Junfeng (Jim) Zhang at the University of Medicine and Dentistry of New Jersey and Rutgers School of Public Health if he would analyze two samples of the granules in Riverside Park for the presence of two kinds of potentially toxic chemicals--polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Dr. Zhang’s lab found that both samples contained six PAHs at concentrations sufficiently high that the New York State Department of Environmental Conservation (DEC) would require their removal if they had been in contaminated soil [3].

We next analyzed three additional samples—one from Sara Roosevelt Park in Manhattan and two from the Parade Ground in Brooklyn. Dr. Zhang’s lab found fewer PAHs, but three of the PAHs were often above the DEC’s contaminated soil limits [4]. Since all the PAHs at elevated levels are likely to be carcinogenic to humans, they are cause for concern [5].

Dr. Zhang’s lab also found worrisome concentrations of zinc and lead [3]. Zinc isn’t necessarily toxic to humans; in fact, a certain amount of zinc is good for our health. But excessive zinc can cause illnesses [6].

Lead was only present in relatively modest concentrations, but health scientists generally believe that no lead should be added to the environment because even low amounts can cause neurocognitive problems in children [7].

Other research, especially that sponsored by the Rochesterians Against of the Misuse of Pesticides in Rochester, New York [8] and that of the Norwegian Building Research Institute [9], is consistent with our findings on PAHs and metals. A recent Connecticut Agriculture Experiment Station study, in addition, has shown that chemicals that are more volatile than PAHs can get into the air, especially when the synthetic turf reaches temperatures over 140 degrees F (which it frequently does in the summer) [10].

Numerous studies have demonstrated that chemicals in whole tires, tire shreds, and recycled tire crumbs can leach into water and soil [10-13]. In addition, many of these studies have demonstrated that the chemicals harm or kill aquatic life, including algae, minnows, trout, and frogs [11]. The chemicals also can stunt the growth of land plants [11]. Researchers have been slower to identify precisely which chemicals in the rubber produce the toxic effects, but researchers generally believe that the culprits include metals such as zinc [11,13]. One investigation implicated PAHs in the death of trout where rubber tires had been placed in water [14].

Two studies specifically asked what happens when synthetic turf granules are placed in water, and both studies found that considerable zinc was released [10, 12]. In a widely cited report funded by a Candadian tire recycling agency, Birkholz and his colleagues [15] discovered that ground-up rubber from a flat playground surface killed aquatic life. Birkholz emphasized that that rubber material was less toxic if it had been on the playground for more than three months, but the effects of ageing merit further study; zinc might actually be released in greater quantities after a few years, as the rubber degrades [12].

Most of this research on non-human organisms, I want to emphasize, has been conducted in laboratory settings. We need more information on whether leaching from rubber kills aquatic life and land plants in everyday outdoor environments.

Similarly, the research on whether toxic chemicals can absorbed by children and athletes who play on synthetic turf fields in very sparse. All we know so far is that toxicants are present in the turf. The research does not show that the chemicals can actually cause children or athletes harm. It doesn’t show that the toxicants can be absorbed into the human body through inhalation, ingestion, or skin contact. This research is just beginning and is critically needed.

Unfortunately, researcher reports have often reached premature conclusions about the turf’s safety. For example, the Office of Environmental Health Hazard Assessment (OEHHA), in report to the State of California, concluded that ingestion of the tiny rubber granules in synthetic turf is of minimal risk [11]. However, this conclusion was based on an estimate of a one-time acute episode. Moreover, the investigators only simulated digestion in the stomach. It would be better to examine digestion processes that include saliva and intestinal fluids.

In one of their studies, the OEHHA [11] estimated that if young children touched a rubber playground mat frequently, and sometimes put their hands to their mouths, over several years they might be at a slightly higher risk of cancer from one PAH. However, this estimate is based on considerable speculation. Still, it alerts us to a potential danger and again points to the need for additional research.

I hope research eventually shows that the granules are safe. In the meantime, I recommend a moratorium on the installation of new synthetic fields. And whatever the results on toxic chemicals eventually show, I hope readers will consider the importance of natural soil and grass for children’s emotional and cognitive development.

References

[1] Juster, T.F., H. Ono, and F. P. Stafford, Changing Times of American Youth: 1981-2003. Institute for Social Research, University of Michigan, 2004. www/umich.edu/news/index.html?Releases/2004/Nov04/r111704a. Hofferth, S.L, and Sandberg, J.F., Changes in American children’s times, 981-1997. In T. Owens and S. Hofferth (eds.), Children at the millennium: Where have we come from, where are we goin?. New York: Elsevier Science, 2001.

[2] Crain, W. The need for free play in natural settings. In J. L. Kincheloe, k. hayes, K. Rose, and P.M. Anderson (eds.), The Praeger Handbook of Urban Education, Vol. 1. Westport, CT: Greenwood Press, 2006.

[3] Crain, W., and J. Zhang. Hazardous Chemicals in Synthetic Turf. Rachel’s Democracy and Health News, No. 873, Sept. 21, 2006.

[4] Crain, W., and J. Zhang. Hazardous Chemicals in Synthetic Turf: Follow-up Analyses. Rachel’s Democracy and Health News, No. 902, April 12, 2007.

[5] International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risk to Humans, PAHs, Vol. 95, 2006. http://monographs.iarc.fr/ENG/Meetings/92-pahs.pdf

[6] ATSDR, ToxFAQs for Zinc, August 2005. www.atsdr.cdc.gov/tfacts60.html

[7] Canfield, R.L., Henderson, C.R., Cory-Slechta, D.A., Cox, C., Jusko, T.A., and Lanphear, B.P. Intellectual impairment in children with blood lead concentrations below

10 micrograms per deciliter. New England Journal of Medicine, 348, 2003, pp. 1417-1526.

Landrigan, P. Testimony to the U.S. Senate Committee on Environment and Public Works, Washington, DC, Oct. 1, 2002. http://epw.senate.gov/107th/Landrigan_100102.htm

[8]. Judy Braiman of the Rochesterians Against the Misuse of Pesticides also found elevated levels of lead in synthetic fields in Rochester, New York (personal communication).

[9] Plesser, T. S. W., and O. J. Lund. Potential health and environmental effects linked to artificial turf systems—final report. Norwegian Building Research Institute (report to the Norwegian Football Association), 2004.

[10] Mattina, M. J., M. Isleyen, W. Berger, and S. Ozdemir. Examination of crumb rubber produced from recycled tires. The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504. 203 974 8449. Sponsored by Environment and Human Health Inc. (EHHI), North Haven, CT.

[11] Office of Environmental Health Hazard Assessment (OEHHA), Evaluation of health effects of recycled waste tires in playground and track products. Contractor’s report to the Integrated Waste Management Board, State of California (Publication #622-06-013), January, 2007, pp. 2, 91, 97.

[12] Hofstra, U. Environmental and Health Risks of Rubber Infill. Summary. INTRON, The Netherlands, February 9, 2007.

[13] Chalker-Scott, L. The myth of rubberized landscapes. Puyallup Research and Extension Center, Washington State University. www.puylyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Myths/Rubber%20mulch.pdf

[14] Stephenson, E, Adolfsson-Erici, M., et al. Biomarker responses and chemical analyses in fish indicate leakage of polycyclic aromatic hydrocarbons and other compounds from car tire rubber. Environmental and Chemical Toxicology, 22, 2003, 2926-2931.

[15] Birkholz, D. A., K. L Belton, and T. L. Guldotti. Toxicological evaluation for the hazard assessment of tire crumb for use in public playgrounds. J. Air & Waste Manage. Assoc., Volume 53, July 2003, p. 904.

William Crain is a professor of psychology at The City College of New York.