Playground arsenic dose relatively low
CHRIS LE
measure to reduce exposure to arwhen to collect urine and saliva Parents should encourage their senic and other contaminants, Le from their children before and after children to go play outside despite recommends installing water taps play. Laboratory analysis separated the modern-day risk of playing on that are easily accessible to chilthe total arsenic in the samples wood treated with chromated copdren so they can wash their hands into nontoxic arsenic species, such per arsenate (CCA). A new ES&T after playing. as arsenobetaine, and the more study (Environ. Sci. Technol. DOI “This is a very interesting and toxicologically relevant inorganic 10.1021/es100128n) finds that arinformative study,” says Stuart Shaand methyl arsenic species. senic exposure from CCA playlat, an environmental epidegrounds is minuscule miologist at the Robert Wood compared with that from Johnson Medical School. The other sources, such as food. arsenic concentrations in the Washing hands after playing Edmonton children’s urine on CCA-treated wood can are consistent with the levels reduce arsenic exposure even Shalat found in a pilot study. further; however, some scien“But I’m not totally reassured tists still advocate a precauthat contact with CCA-treated tionary approach by wood is not a significant removing the wood from source of arsenic exposure,” playgrounds. he says. The children in Le’s Once marketed as “presstudy were 7 years old. “The sure-treated,” CCA-treated greatest risk is with 2-yearlumber that fights fungi and olds, whose hands are in their insect damage contains the mouths all the time,” he most toxic inorganic form of Washing hands after playing is still a good commonsense measure, despite the finding that the exposure to warns. arsenic. Arsenic, ranked first arsenic from CCA-treated structures is minimal. “It may be encouraging that on the U.S. EPA’s 2005 and arsenic from CCA playgrounds is “We found that the sum of inor2007 priority hazardous substances not in children’s body fluids, but ganic and methyl arsenic species in list, is a potent carcinogen and that doesn’t mean it is not a proburine was 15 µg/L in the CCA toxicant. Since early 2004, the lem in the environment,” cautions group and 12 µg/L in the non-CCA wood preservation industries in Howard Mielke, an urban group,” Le says. The differences Canada and the U.S. have voluntargeochemist at Tulane University. between the two groups were not ily ceased to use CCA for residenThe average concentration of arstatistically significant and were tial wood products. senic in CCA-treated wood is within the range of normal back“About 70% of homes and play1500–3300 parts per million (ppm), ground levels of arsenic in urine in grounds have CCA-treated wood,” which meets EPA’s criteria for hazthe general population. says Chris Le, an analytical chemist ardous waste. In a new study, “The finding seemed to be surat the University of Alberta Mielke found that the median arprising at first, but if we consider (Canada) and co-author of the senic concentration in soil under the relative contributions of arstudy. Neither Canada nor the U.S. CCA play areas in New Orleans was senic from different sources that have regulations governing what to 57 ppm, compared with backcould end up in the body, our redo with this wood in existing decks ground levels of 1.5 ppm in soils sults make sense,” Le explains. and play equipment, leaving some throughout the rest of the city. Earlier studies have shown that parents unsure about allowing their “If we want to protect our chilchildren romping on CCA playchildren to play on the structures. dren, don’t expose them to toxicssif grounds pick up an average of “There is no question that chilwe find arsenic in the environment, 0.56 µg of arsenic on their hands. dren are exposed to arsenic when we should deal with it directly,” Even if this entire amount were they contact CCA-treated wood, Mielke concludes. In fact, Norway consumed, it pales in comparison but what was not clear was the has taken a more precautionary apto the roughly 15 µg ingested magnitude of exposure, the dose,” proach by removing CCA-treated each day in food, he says. Le says. His research team visited 8 wood and contaminated soil at 6,000 “It is more important for chilCCA and 8 non-CCA playgrounds daycare centers and 40,000 elemendren to be physically active than to in Edmonton and obtained consent tary schools and parks, he says. worry about the exposure to arfrom the parents of 66 children to senic from the playground,” Le participate in the study. The scien—JANET PELLEY points out. As a precautionary tists taught the parents how and 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / May 15, 2010
10.1021/es101119b
2010 American Chemical Society
3650
Published on Web 04/26/2010
