Arsenic is a subtle toxin, and one that could be sitting beneath your child's fingernails. According to a recent pilot study published by the Tulane/Xavier Center for Bioenvironmental Research (CBR) titled "New Orleans soil arsenic surveys: Children's play areas possess localized hazards," high levels of arsenic sit on at least 14 New Orleans playgrounds.
Combined in chromated copper arsenate (CCA), arsenic works with copper as a one-two punch against fungi and insects. The formula, a mix of copper with chromium and arsenic, acts as a wood preservative and shields against rot and wood-eating insects like termites. Chromium acts as a binding agent for the other two chemicals; copper prevents decay, and arsenic is the insecticide.
The chemical has been used to pressure-treat wood since the 1940s, but in January 2004 the Environmental Protection Agency restricted its use and suggested techniques to prevent the chemical from leaching from the wood into its surroundings. CCA had been used to treat commercial timber, or more specifically, playground structures.
CBR researchers suggest more than one-third of New Orleans play areas containing CCA-treated wood also contain arsenic contaminants in the soil. The research team surveyed 38 play areas containing wood structures, and of the 132 samples, 75 contained CCA-treated wood.
"You're presenting something to children that is actually very toxic. It's like presenting them something with lead-based paint," says CBR research professor Howard Mielke. "We've taken it for granted that things on the market are safe, and the producers don't have to tell you if it's safe because they were never asked to look for it."
The Louisiana Department of Environmental Quality (DEQ) holds that a "safe" soil-arsenic level should reach no more than 12 parts per million (ppm). The team found a citywide soil-arsenic median of 1.5 ppm (or 1.5 milligrams per kilogram), but the median of contaminated sites was 57 ppm — 38 times the citywide median and almost five times the amount considered safe by the DEQ.
"We've never seen those kinds of numbers before," Mielke says. "You get a sense of what we're talking about when arsenic in the soil is measuring in the 50s. You're talking about many times the standard."
Since CCA was taken off the market following the EPA's 2004 appeal, the EPA now suggests using regular coats of penetrating wood stains and paint on treated wood to prevent its chemicals from leaching.
Arsenic ranks first on the Comprehensive Environmental Response, Compensation and Liability Act of 1980's (CERCLA, also known as Superfund) 2005 and 2007 hazardous substances priority lists. Under the EPA, CERCLA cleans and enforces hazardous waste sites. CERCLA's cleanup list contains more than 1,200 sites. As of press time, Louisiana has nine sites on the list, with three more proposed — but none of them are playgrounds.
Though no amount can be considered truly safe, contact with arsenic may cause cancer of the bladder, skin and lungs, and has been attributed to birth defects, cardiovascular disease and neurological disorders.
"Arsenic is a very well known carcinogen recognized for its neurotoxicology,; it's poison," Mielke says. "If children get involved in arsenic, they're going to be sensitive to the impact of it, the neurotoxicity, the peripheral neuropathy, the nerves being affected at the tips of the fingers, hands, to more general neuropathy, and various pathologies of the nervous system.
"Children are presented with what adults give them. They don't have the ability or standing to speak up and say 'Hey, this is toxic, you can't put this out there,' so we have to do it — and we're not very good at doing it."
Mielke estimates that cleaning could cost thousands of dollars. Site managers would have to completely remediate the grounds, replace and remove the tainted soil, send it to a hazardous waste disposal, and examine the structures. Mielke has helped remediate contaminated sites using clean soil and geotextiles, but playground managers are working within severely limited school and city budgets.
Mielke tested Louise S. McGehee School's playground before Katrina, after the school expressed concerns about pale greenish woodchips on the site. "That's when we checked it, and indeed, it was very high in chromium, arsenic and copper." The woodchips lining the playgrounds were taken from CCA-treated wood. The results showed levels of arsenic at 813 to 1,654 ppm.
The school responded by immediately replacing the woodchips. "[The school] took our measurements to heart and immediately took everything out," Mielke says. "We tested it afterwards and it came out very clean."
McGehee headmistress Eileen Powers says she read an article about potential arsenic hazards and decided to call Mielke about the site. Mielke sent his graduate students to test the grounds. "Subsequent to testing the playground we replaced all the woodchips with mulch from untreated trees, and we did some work on the wood, and afterwards we replaced the playgrounds entirely," she says. "Now they're all (made with) synthetic materials with recycled tires."
Mielke has acted as a consultant to the school to test the campus' older structures. "We have a beautiful campus, but it's made largely of older buildings," she says. "He's been helpful when we need testing."
Playground contamination isn't unique to New Orleans. Mielke's team says similar arsenic hazards exist in play areas throughout the country. Though federal floodwaters in 2005 spread hazardous waste throughout the city, soil near play structures still tests higher than ever for unsafe levels of arsenic.
In a separate study ("Arsenic contamination in New Orleans soil: Temporal changes associated with flooding"), published in the journal Environmental Research last August, researchers (including Mielke) found a 19.67 ppm average difference between citywide pre-Katrina and post-Katrina soil-arsenic levels. In an 18-month recovery period following Katrina, 97 percent of the tested sites decreased their toxicity. Samples reached an average of only 3.26 ppm. However, 21 of the samples (or 30 percent) had higher concentrations than their pre-Katrina level. And of the city's play areas included in the survey, 33 percent of schoolyards and 13 percent of playgrounds increased arsenic concentration above screening guidelines within the recovery period. The study determined a "potential long-term soil concentration" of arsenic, finding not only floodwater-embedded chemicals in New Orleans soil and not just on its surface, but also pointing to potential structural problems.
The Natural Resources Defense Council's (NDRC) August 2007 report ("Katrina's Wake: Arsenic-Laced Schools and Playgrounds Put New Orleans Children at Risk") found similar results. Arsenic hotspots appeared throughout the city's school playgrounds in Gentilly (Alexander Milne Playground and Schabel Playspot had the highest arsenic readings, at 18 ppm and 19.3 ppm respectively), Lakeview, Bywater, Mid-City, New Orleans East and Uptown.
Schools exceeding the "safe" levels included McDonogh Elementary, Dibert, Drew Elementary, Craig Elementary, Medard H. Nelson Elementary and McMain Magnet Secondary.
Samples were taken in March 2007 following the EPA's testing of flooded sites, which identified surfaces with high concentrations of arsenic as well as lead and other contaminants following Katrina's aftermath. The EPA and DEQ declined to perform a cleanup of the affected areas, claiming the high arsenic levels existed before Katrina. In August 2007, the DEQ performed sampling at four schools, and the NDRC sent cleanup aid and consultation.
With the CBR's 2009 pilot study, Mielke sees the current arsenic concentration as "a problem that has crept up on our city and most people aren't even aware of it.
"We're not the only ones who've been caught with this," he says. Mielke has helped the country of Norway develop cleanup programs for hazardous sites, "and they're cleaning them up as fast as they can," he says. The national program tests playgrounds in child care centers, elementary schools and public parks for a wide range of toxic substances, including arsenic, lead, mercury, PCBs (polychlorinated biphenyls) and PAHs (polycyclic aromatic hydrocarbons).
The CBR survey "was just a summer project for some students who worked with me at Tulane, and they went around the city and did the best they could at locating (sites), and they ended up with 38 play areas," Mielke says. "It's a warning."