The lowdown on lead in synthetics

Around April 20, headlines across the counry were touting the “dangers of lead in artificial turf.”It all started when Ironbound Park in New Jersey was tested for heavy metals because of its proximity to a neighborhood scrap yard. Samples taken by officials with the New Jersey Department of Health and Senior Services (NJDHSS) and the EPA tested positive for high levels of lead. Further testing determined that the source of the lead was the synthetic turf. Pigments used for colorfastness contained lead chromate at around 4,000 milligrams per kilogram. This is 10 times the amount of lead considered acceptable under New Jersey’s residential soil standard for the cleanup of contaminated properties. That information set off a media frenzy across the country.

Photos by Steve Trusty.
The synthetic field becomes the lounging area for young athletes at track meets.

It is interesting to note that the city of New York issued a report on April 15 titled “Lead Hazard Risk Assessment of Synthetic Turf Playing Fields, March 2008.” This assessment was prompted by the discoveries in New Jersey. The report details the testing conducted on four fields operated by the department of parks and recreation. Two of the fields had synthetic turf similar in age and type, and purchased from the same manufacturer as the field in Newark. Two fields containing crumb rubber were also tested for lead. Using a variety of tests and assessments, the conclusion was that lead hazards were not present in any of the four fields, and no regulatory limits for lead in any samples were exceeded. This report was issued four to five days before all the media attention and about a month after the discovery in New Jersey.

Warm-up clothes are tossed on the synthetic field surface during competition.

The Synthetic Turf Council (STC) released a report on April 21 from two scientists. Dr. David Black, Ph.D., forensic toxicology, and Dr. Davis Lee, Ph.D., synthetic organic chemistry, issued a joint statement that stated: “There is no scientific evidence of a health risk for children or adults based on recent test results and current knowledge of the chemical structure of aged synthetic turf products. Concerns over potential harm related to the three older fields in use in New Jersey have not addressed fundamental questions regarding potential toxicity including route of exposure, dose of any potential chemicals, and how such chemicals may be introduced into the body by being in contact with synthetic turf products (referred to as bioavailability). Reports of health concerns have not been supported by any laboratory analysis on the products or humans that indicate any risk of harm due to potential exposure to chemicals. Studies that have been conducted and made available for our review have not documented that aged synthetic turf products may be a source of lead exposure to anyone in contact with the product.”

Trace amounts of lead exist in everyday products. The lead found in some of the synthetic surfaces is lead chromate. It is used to extend the yarn color lifespan in those products. It is encapsulated in plastic to prevent any health risks.

Stretches and warm-up runs take place next to each other on the synthetic turf field.

On May 5, AstroTurf and General Sports Venue held a press conference at the New York Public Library for Science, Industry and Business. Doctors Black and Lee, along with Dr. James Coughlin, Ph.D., agricultural and environmental chemistry, and Dr. C. Ralph Buncher, Sc.D., biostatistics and epidemiology, provided most of the information. They listed the following seven conclusions.

1. CDC Lead Prevention Program identifies no risk from synthetic turf.
2. Lead does not leach from synthetic turf.
3. Bioavailability of lead from pigment is extremely low.
4. Dust at Ironbound Stadium posed no inhalation hazard for lead.
5. Children with regular exposure to the Ironbound field tested normal for lead.
6. Factory workers exposed to nylon turf and particles for 30 years tested normal for lead.
7. Amount of ingested turf required to pose a threat is absurdly unrealistic.

Based on the concentration of lead in lead chromate, and assuming 50 percent bioavailability, a 50-pound child would have to ingest 10.8 square feet of synthetic turf to a 90-PPM dose of lead. The same child would have to ingest 71.1 square feet of turf to get a 600-PPM dose, the U.S. federal limit. That equals almost half the child’s weight (23 pounds).

The Consumer Products Safety Commission (CPSC) held a roundtable on May 13 entitled “Understanding the Pending Lead Legislation and the Use of Lead in Consumer Products.” This discussion included presentations by CPSC staff and representatives of several diverse groups affected by lead legislation. As evidenced by these groups, lead affects the toy industry, paint and coatings, vinyl, jewelry, textiles, clothing and synthetic turf. According to the list of preregistered and on-site registrants, 214 people attended this discussion. Rick Doyle, president of the Synthetic Turf Council (STC), gave the last of the eight industry presentations. His presentation included the following STC objectives.

A close-up of a synthetic turf surface and the crumb rubber infill. A shoe helps show the crumb rubber particle infill and turf fibers of this synthetic field.

To cooperate with the CPSC to develop:

•  A workable and reasonable standard and phase-in period for lead chromate in the formulation used to make synthetic turf.

•  Clear and objective terminology to describe acceptable or undetectable levels of lead chromate in synthetic turf, e.g., “lead-free” as used to describe lead-free gasoline.

Doyle’s report also provided information on how and why lead chromate was used in synthetic turf and how lead chromate is different from lead carbonate (soluble lead formerly found in lead paint). He stated that lead chromate is “almost completely insoluble, silica-coated, encapsulated in resin, diluted and has extremely low bioavailability—it is not absorbed by the body if ingested or inhaled.” He provided data from the CDC Lead Prevention Program—1997-2006 that of 763,216 childhood exposures to lead, there were no risks from synthetic turf, and that out of 40,000 cases of high blood lead concentrations in children reported in 2006, none were attributed to exposure to synthetic turf.

The author is a contributing editor for SportsField Management.

Resources

For more information and to keep up to date on this topic, check these Web sites:

Synthetic Turf Council
www.syntheticturfcouncil.org

Ohio State University
http://www.hcs.osu.edu/sportsturf

Consumer Products Safety Commission
www.cpsc.gov