Health Impacts
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Children's Health
Vulnerability
of Children
International
Research
Australian
Testing
Variability
in Tests
References
The findings that heavy metals can be dislodged from CCA-treated timber has raised concerns about the health impacts of this on children. This is because children are especially vulnerable due to:
- their hand-to-mouth behaviour which can transfer the heavy metals into their bodies both during and after play (CPSC, 2003a),
- their close contact with treated timber structures when playing in backyard cubby houses and crawling and sitting on decks,
- their faster metabolic rate (Belluck et al, 2003).
There is a lack of direct health studies to determine how arsenic affects children so extrapolations have to be made from studies on adults or rats. Currently, risk assessment is undertaken to determine the lethal dose for 50 percent of rats (LD50), and this is then extrapolated to an 80 kilogram male adult, and further extrapolations have to be made for a child. As Jo Immig of the APVMA’s Community Consultative Committee remarked, ‘children are the most vulnerable in our society, and health standards needs to be calculated to protect them’ (Pers. Comm, 22/11/04).
Belluck et al (2003) warn that infants and children may be more susceptible than adults to arsenic exposure, with ingestion of soil as the main pathway for arsenic intake. Another means of exposure is through children handling treated timber play equipment and then putting their arsenic-coated hands in their mouths. Children living near industrial and hazardous waste sites may also be at risk through dust inhalation. The health symptoms experienced by children exposed to high levels of arsenic have been found to be similar to adults, and including respiratory, cardiovascular, dermal and neurological effects.
A number of overseas studies have been undertaken to find out the amount of arsenic, chromium and copper that can be dislodged and ingested from contact with CCA-treated timber. The amounts of arsenic dislodged from CCA-treated timber varies from study to study. The table below displays some of this information for ease of comparison.
| Source | Finding |
|---|---|
| Sharp and Walker (2001) | ‘A 4-6 year old child’s daily exposure to arsenic has been found to be 5 micrograms/l in food, 23 µg/L in water, 25 µg/L from playing on CCA-treated wood and up to 480 µg/L from playing on CCA treated playground equipment’ (p.1). Children could exceed the legally-acceptable lifetime cancer risk in 2 weeks by paying on a treated play set. |
| Anon (2004) | 7 of 20 play areas in Central Park, New York tested positive for arsenic above safe levels. The highest reading (316.6 µg) is a 1-in-500 lifetime risk of lung or bladder cancer if playing there three hours a week from ages 1 to 6. The play equipment was all regularly painted or sealed with polyurethane. |
| Sharp et. al. (2001) | Wipe tests the size of an average four-year-old child’s hand found 18 to 1,020 µg arsenic, more than the US EPA’s proposed 10 µg per day allowable exposure level for arsenic in drinking water. It was estimated that 1 in 500 children regularly playing on treated play sets will develop lung or bladder cancer in later life due to this exposure. |
| Lerche Davis (2003) | ‘In the US’ southern states, 10% of all children face a cancer risk that is 100 times higher because they spend more time outdoors playing’. |
| Kwon et al (2004) | The mean amount of arsenic on children’s hands from CCA-treated playgrounds was 0.50 µg, significantly higher than the control mean amount of 0.095 µg. The maximum amount logged, however, was less than the Canadian allowable daily intake of arsenic (4 µg) in water and food. |
| Enviros Consulting et al (2003) | Sand from sand playboxes built from treated wood contained a maximum of 12.9 mg arsenic per kilogram of sand 2 to 4 years after construction. Natural soils may contain from 1 to 50 mg arsenic/kg. Little risk to children being poisoned by eating the sand. |
The Consumer Product Safety Commission also conducted peer-reviewed scientific studies of exposure to arsenic via playground equipment. Their scientists found that ‘exposure to arsenic from CCA-treated playgrounds could be a significant source of arsenic’ for children (CPSC, 2003a). They estimated that children between 2 and 6 years old who play regularly on CCA-treated playground equipment have a significantly increased lung or bladder cancer risk over their lifetimes (CPSC 2003b: 1).
In Australia, children are likely to spend more time outdoors playing on treated timber equipment than in many northern industrialised nations because of the warmer more temperate climate. However, Australian authorities have been remiss in not carrying out any soil or wipe test in children’s playgrounds. The only known published residue testing carried out in Australia since CCA-treated timber was put on the market was a limited wipe test on playground equipment in the City of Maroondah, Victoria. The tests were commissioned by the Croydon Conservation Society and undertaken by the State Chemistry Laboratory, in June 2003. Noting that the maximum safe amounts of arsenic in Australia for a 12kg child is 3.4 µ/day, the results showed a range of 21 µg to 710 µg from a single wipe, compared to a background control of less than 0.1 µg (See Table 2.3 below). These amounts available to children from contact with the CCA-treated timber far exceed the maximum amount of arsenic allowed in a glass of drinking water (Loveridge, 2004b).
Results from wipe-testing of playground equipment in City of Maroondah
| Sample | Total
Arsenic (µg) |
Total
Chromium (µg) |
Total
Copper (µg) |
|---|---|---|---|
| 1 | 21 |
22 |
20 |
| 2 | 24 |
23 |
22 |
| 3 | 91 |
190 |
88 |
| 4 | 140 |
630 |
140 |
| 5 | 710 |
310 |
670 |
| Control | <0.1 |
<0.6 |
<0.2 |
Source: Loveridge, 2004
As described in more detail in the section on Environmental Impacts, there are a number of factors that control the level of dislodgement, or leaching from CCA-treated timber, including:
- acidity of the wood and surrounding soil,
- UV exposure, and
- amount of weathering to the wood.
Some of these factors contribute to the range of heavy metal levels found to wipe off during testing.
References:
Anon, (2004), ‘Playground Poison’, The New York Post, August 15.
Belluck, D., Benjamin, S., Baveye, P., Sampson, J., and Johnson, B. (2003), ‘Widespread Arsenic Contamination of Soils in Residential Areas and Public Spaces: An Emerging Regulatory or Medical Crisis?’, International Journal of Toxicology, 22, pp. 109-128.
CPSC (2003a), Fact Sheet: Chromated Copper Arsenate (CCA) -Treated Wood Used in Playground Equipment, U.S. Consumer Product Safety Commission, February 7, http://www.cpsc.gov, (accessed 16/8/04)
CPSC (2003b), Briefing Package: Petition to Ban Chromated Copper Arsenate (CCA)-Treated Wood in Playground Equipment (Petititon Hp 01-3). Washington, DC: US Consumer Product Safety Commission (CPSC). February.
Enviros Consulting and The BioComposites Centre, University of Wales (2004), Treated Wood Waste: Assessment of the Waste Management Challenge, The Waste & Resources Action Programme (WRAP), UK.
Gray, S. and Houlihan, J. (2002), All Hands on Deck, Washington, D.C.: Environmental Working Group (EWG). August. http://www.ewg.org/reports/allhandsondeck
Lerche Davis (2003), ‘Carcinogens in Playsets, Decks, Picnic Tables’, WebMD Medical News, November 14, http://my.webmd.com/content/article/77/90361.htm?z=3734_00000_1000_ts_02 (accessed 11/11/04).
Kwon, E., Zhang, H., Wang, Z., Jhangri, G., Lu, X., Fok, N., Gabos, S., Li, X-F, and Le, X. (2004), ‘Arsenic on the Hands of Children after Playing in Playgrounds’, Environmental Health Perspectives, 112:1375–1380.
Loveridge, K. (2004), Letter to Premier Steve Bracks, April 11.
Sharp, R. and Walker, B. (2001), Poisoned Playgrounds: Arsenic in 'Pressure-Treated' Wood, Environmental Working Group and Healthy Building Network, Washington D.C. http://www.ewg.org/reports/poisonedplaygrounds
Sharp, R. et. al. (2001), The Poisonwood Rivals: High Levels Of Arsenic Found In Lumber From Home Depot & Lowe's, Environmental Working Group and Healthy Building Network, Washington D.C. http://www.ewg.org/reports/poisonwoodrivals/poisonwood.pdf