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Playgrounds, Wood, and Risk
Bullies would call people sissies for being afraid of swing sets, but some of those same bullies probably grow up to complain about chemicals in their environment, which are far less dangerous than swing sets. Take the case of pressure-treated wood.
A few years ago, there were warnings in the news that pressure-treated wood — which contains chemical preservatives that fend off fungus, termites, and other menaces — might pose a hazard. Gardeners were told to avoid constructing pressure-treated wood borders around their vegetables. Parents were told to keep their children away from swing sets made of pressure-treated wood lest arsenic leach from the swings and harm the children (special fear for the children is common in anti-chemical campaigns but almost always unwarranted, as explained in the ACSH book Are Children More Vulnerable to Environmental Chemicals?). Both the EPA and Consumer Product Safety Commission concluded, however, that the amount of chemicals that leaches from the wood is negligible and poses no health threat.
Nonetheless, responding largely to consumer fears driven by media attention to the issue, EPA and the CPSC announced last month that by the end of the year, use of the chemical CCA in pressure-treating wood will be phased out and alternatives sought. Interestingly, the very same EPA announcement that describes the impending phase-out notes that the EPA does not recommend dismantling or avoiding existing pressure-treated wood structures and notes that discarded pressure-treated wood is considered non-hazardous waste. The underlying health facts have not changed, but fear and precaution have subtly altered future construction plans.
The benefits of pressure-treating wood are substantial, since it lasts far longer (remains sturdier) than untreated wood. But just knowing that the chemicals were in there was enough to frighten some people — even if the chemicals were fixed to the wood and thus insoluble and leach-resistant. The latest anti-chemical campaign made countless parents just a bit more frightened about their kids' world.
Compare that hoopla to the much greater risk posed by ordinary playground visits, which no one worries about much simply because playgrounds are so familiar and accepted.
There are about half a million playground-related injuries a year — mostly falls onto hard surfaces or equipment — according to HealthScoutNews, and those injuries "cost the nation more than $1 billion in medical bills, work loss, pain, suffering, and legal liabilities." The American Academy of Orthopaedic Surgeons recommends adult supervision, careful checks for broken or sharp-edged equipment, relatively soft materials such as wood mulch under high equipment, and division of playgrounds into areas for highly physical play and areas for more passive activities (such as using sandboxes), as well as division into areas for younger and older children.
We aren't recommending that people fear playgrounds. On the contrary, we are struck that people learn to live quite comfortably with all sorts of boring, everyday risks — and lead fulfilling lives — but become paranoid once something that sounds exotic, new, and threatening comes along. It's predictable, but that doesn't mean it makes sense.
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| Responses:
April 12, 2003
Thanks for your, as usual, factual and rationale rebuttal. I wonder if we are actually missing a point — the potential for increased accidents when decks and playground equipment are manufactured out of untreated wood, which can rot to tissue paper under the protective paint layer and look perfectly sound — until one day it collapses in part or in whole, with a child or adult on it.
We owned a non-pressure-treated wooden swing set, which I tried to keep painted and repaired. Even so, one day it collapsed under my five-year-old daughter, fortunately without major injury, because the rot had been concealed by all the paint.
David C. Griffith
Program Development Manager
Fuels Technology
ConocoPhillips
Houston, TX
April 16, 2003
Dear All,
I read the executive summary of your organization's Are Children More Vulnerable to Environmental Chemicals? paper (and many others). Perhaps you would be interested in the following point, which I believe is connected to above topic. One point of concern discussed here in Europe in recent years was connected with chemicals adsorbed to indoor house dust, which is taken up by babies in much higher quantities than by adults (and have much lower body weight). Experts assume a daily uptake of house dust by babies (from wiping and licking fingers, floors, etc.) of some 4 to 10,000 mg dust/d, quite a big variation, with most experts assuming around 100 mg dust/d. I did try to make a calculation of maximum dust quantities to be licked up by babies.
Some basic facts necessary for risk assessment of house dust
1. How much dust in houses? Recent measurements report some 22 micrograms dust/cubic meter (smokers having 35 micrograms dust/cubic meter) (see MUE99). We take 22 micrograms/cubic meter as the normal value. From this we derive as a worst case the dust quantity that can be formed in a house during a day: 660 micrograms/square meter (12 air exchanges per day, 2.5m height in a room). This corresponds to some 100 mg dust/d in a house with 150 square meters area to live.
2. How much dust inhalation? An adult will inhale a maximum quantity of 6.3 micrograms/(kg bw*d). (22 micrograms/cubic meter, body weight (bw) of 70 kg; 20 cubic meter/d air inhalation; children other values).
3. Oral intake of dust? Normally, oral intake for children of 100 mg dust/d is assumed (in the literature 4 to 10,000 mg dust/d can be found [PA97]). This corresponds to all the dust created daily in a 150 square meter house (see item 1.). Greenpeace and others base their risk assessment for children on this overly high intake. Unhappily, we cannot give a "right" maximum oral intake for children — but we cannot believe that a child could eat all the dust created in a 150 square meter compartment or lick the whole bottom of such a compartment.
I have the impression that this is one of those cases where we get scared by numbers derived from data that cannot be justified and seem to be too high anyway.
Another point often neglected is the bioavailability of substances adsorbed to dust. For dioxins, we know from many experiments that the body load of fire-exposed people is no higher than that of unexposed people, suggesting that either the uptake is quite low or that the bioavailability is quite low, which can also be studied through experiments.
Sincerely,
Dr. Ernst-Josef Spindler
PVC und Umwelt Vinnolit
GmbH & Co.
KG D-84489 Burghausen |
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