(Beyond Pesticides, November 25, 2009) Although phased out from use in playground, deck and landscaping timbers, chromated-copper-arsenic (CCA), a hazardous wood preservative still allowed for use on utility poles, continues to be found on children’s playgrounds. Researchers at Tulane University sampled playgrounds from the city of New Orleans metropolitan area and found significant amounts of arsenic in the soils.
Tulane University’s Center for Bioenvironmental Research Howard Mielke, PhD and his colleagues, concerned about risks to children posed by treated wood, used a portable X-ray fluorescence instrument to survey playgrounds for arsenic. Their results, presented at the 30th annual North American meeting of the Society of Environmental Toxicology & Chemistry and entitled “Soil arsenic surveys of New Orleans: Localized hazards in children’s play areas,” finds that 56.8% of wood sampled are treated with CCA and 78% of soils sampled from playgrounds contain levels of arsenic greater than the state “acceptable” level. One playground in particular contains CCA-treated wood that had been chipped and used as a cushioning ground surface around slides, swings and other equipment from which a child might fall. These chips contain high concentrations -813 to 1,654 ppm- of leachable arsenic. Note: The researchers informed the school of the high arsenic concentrations and the tainted chips were replaced with untreated bark.
The researchers also examined the effect of a child’s ingestion of contaminated soil. Soil samples were digested in one-molar nitric acid, a solution meant to mimic the pH of a child’s stomach, and found that the median arsenic concentration which resulted was on the order of 57 ppm – a concentration much higher than the median of 1.5 ppm in soils generally found throughout the city of New Orleans.
“The irony,” Dr. Mielke contends, “is that if you want to find arsenic in soil, go to a child’s play area with wood structures.” They will likely be pressure treated with the CCA combo and leach substantial quantities of this carcinogen and neurotoxic agent into soil. And he predicts New Orleans’ arsenic hazard will not prove unique: “I would expect to see it all over the country.” For decades, CCA-treated lumber was the wood of choice, nationally, for play structures, picnic tables, decks and fencing.
Researchers also found that many child-care centers do not want to know the results of their study and, as a result, parents are often the last to know of any problem. “We found that when we were going to take samples at child-care centers, we quickly learned they don’t want to know the results,” remarks Dr. Mielke. There are no requirements that playground managers survey for arsenic in soil, but they could face liability issues if they learned they had a problem and did not immediately shut down until tests confirmed the area was clean. “So for our study, we agreed to take the samples and not give them the results until after we were done [cleaning up the site],” says Dr. Mielke. This offers many facilities plausible deniability of any preexisting problem.
The cost of cleaning up contaminated wood is not enormous, perhaps a few thousand dollars per playground (Dr. Mielke’s estimate from having worked to clean up several in town), but still beyond the discretionary budgets of cash-strapped parks and schools. However, removing contaminated soil, which is considered hazardous material, can be a problem. Soil must be placed at a hazardous waste facility and the cost for removal, as well as special equipment to dig contaminated materials out can be extraordinarily high.
Beyond Pesticides has called for a banning of heavy duty wood preservatives and said that the slow phase-out of residential uses of these chemicals does not adequately protect public health or the environment. Wood preservatives are known to leach from previously treated wood and children, as demonstrated in this study, are at risk when they put their unwashed hands in their mouths after touching soil or wood that is contaminated with preservatives. Although, as of January 2004, most residential uses of CCA can no longer be manufactured for decks and patios, picnic tables, playground equipment, walkways/boardwalks, landscaping timbers, or fencing, already existing residential CCA-treated wood and structures may continue to be sold and used. Continuing uses, such as utility poles, continue to be manufactured and put workers and the public at risk. For Beyond Pesticides’ Resource Kit to take action in your community and state, go to our wood preservatives Resources and Toolkits page.
For more information on CCA and other wood preservatives visit our Wood Preservative program page.
Source: Science News