Rachel's Democracy & Health News #992, April 12, 2007


[Rachel's introduction: Some U.S. cities are replacing soil and grass with synthetic turf in parks, playgrounds and ball fields. Here two researchers report measuring toxic chemicals in sythetic turf at levels that exceed New York State's allowable standards for soil. This is a follow-up to an earlier study.]

By William Crain and Junfeng Zhang

Across the country, communities and private sports facilities are installing the "new generation" synthetic turf. Compared to the old AstroTurf, the new synthetic turf is springier and feels more like natural grass. However, the new turf is being installed before there has been thorough research on its health risks.

We have been especially concerned about the possibility that the rubber granules that contribute to the new turf's resiliency contain toxic chemicals. The granules rest between the plastic grass fibers, but they also are common on the surface, so children and athletes come into frequent contact with them. In fact, many players have told us that the granules get into their shoes and wind up in their homes.

In the September 21, 2006 issue of Rachel's Democracy and Health News (#873), we reported on our initial chemical analyses of rubber granules in the new synthetic turf in Manhattan's Riverside Park. Specifically, we wanted to see if the granules contained any of 15 polyclyclic aromatic hydrocarbons (PAHs) on the U.S. Environmental Protection Agency priority pollutant list. The results revealed worrisome levels of six PAHs: benzo(a)anthracene, chrysene, benzo(b) fluoranthene, benzo(a)pyrene, benzo(k)fluoranthene, and dibenzo(a,h) anthracene. These PAHs were in concentrations that the New York State Department of Environmental Conservation (DEC) considers sufficiently dangerous to public health to require their removal from contaminated soil sites.[1] Each PAH might well be carcinogenic to humans.[2]

In the above study, the brand of synthetic turf was A-Turf. We need to know if PAHs are also present in other brands in other parks. In October 2006 and January 2007, we analyzed additional samples of rubber granules-two samples from the large playing fields in the Parade Grounds in Brooklyn and one sample from the small Sara D. Roosevelt Park in Manhattan. The manufacturer of these artificial fields was FieldTurf, the country's most popular brand (www.fieldturf.com). The Parade Grounds fields were over three years old; the Roosevelt Park field was five months old. As in our earlier investigation, a Soxhlet apparatus with organic solvents was used to determine the maximum extractable amounts of the 15 PAHs.

Using the DEC's contaminated soil site standards[1] as our benchmark, we found three PAHs to be at hazardous levels in at least one sample. The concentrations of these three PAHs are listed in Table 1.


Table 1. Concentrations of PAHs in Rubber Granules (ppm*)

....................... Sample... Sample.. Sample... DEC
....................... 1**...... 2**..... 3***..... Contaminated
.................................................... Soil Limits

Chrysene .............. 1.96..... 1.34.... 0.06..... 1.0
Dibenzo(a,h)anthracene. 0.71..... 0.52.... 1.43..... 0.33
Benzo(b)fluoranthene... 1.08..... 0.58.... 0.20..... 1.0

* ppm = parts per million

** Parade Grounds in Brooklyn
*** Roosevelt Park in Manhattan


As we can see in Table 1, the PAH that exceeded the DEC's tolerable level in all three samples was dibenzo(a,h)anthracene. The International Agency for Research on Cancer (IARC) considers this PAH to be one of the most dangerous. Although more is known about PAH toxicity to nonhuman animals than to humans, the IARC lists dibenzo(a,h)anthracene as a probable human carcinogen. It lists chrysene and benzo(b)fluoranthene as possible human carcinogens.[2]

In conclusion, the present study found fewer PAHs that were at hazardous levels, compared to the previous study. Even so, the presence of any hazardous PAH concentration is a cause for concern.

Additional evidence of elevated PAHs in rubber granules comes from a 2004 study in Norway. Analyzing other brands of synthetic turf, the investigators found several PAH concentrations that were above Norway's land use standards.[3]

The next step is to study the bioavailability of PAHs -- that is, the likelihood that they can be absorbed into the bodies of children and athletes through pathways such as skin contact and ingestion. Thus far, the research on this topic is very limited,[4,5] and the major study was apparently industry-funded.[4] Until much more research is conducted, a moratorium on new synthetic turf installations would be prudent.


[1] 6 NYCRR Subpart 375-6, Remedial Program Soil Cleanup Objectives, Effective Dec.14, 2006. Department of Environmental Conservation, Tables 375-6.8 (a) and (b).

[2] International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risk to Humans, PAHs, Vol. 95, 2006, p. 18.

[3] Norwegian Building Research Institute. Potential health and environmental effects linked to artificial turf systems -- final report, 2004.

[4] 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.

[5] Nilsson, N. H., A. Fielberg, and K. Pommer. Emission and evaluation of health effects of PAHs and aromatic amines. Survey of Chemical Substances in Consumer Products, no.54. Danish Ministry of the Environment, 2005.


Note on authors' affiliations:

William Crain, Ph.D., is professor of psychology at The City College of New York and president of Citizens for a Green Riverside Park. Billcrain@aol.com

Junfeng (Jim) Zhang, Ph.D. is professor and acting chair, Department of Environmental and Occupational Health, the School of Public Health, the University of Medicine and Dentistry of New Jersey and Rutgers University. Jjzhang@eohsi.rutgers.edu