Researchers: Treated wood poses long-term threat
GAINESVILLE, Fla. — Arsenic from treated lumber used in decks, utility poles and fences will likely leach into the environment for decades to come, possibly threatening groundwater, according to two research papers published online Wednesday.
Researchers from the University of Miami, the University of Florida and Florida International University examined arsenic leaching from chromated copper arsenate, or CCA-treated wood, from a real deck as well as from simulated landfills.
Their conclusion: The deck wood leached high levels of arsenic into rainwater runoff and the soil — and treated wood only continued leaching arsenic while sitting in simulated landfills.
The papers appeared in the online version of the journal Environmental Science & Technology, Research ASAP. The bulk of the funding for the research came from the Florida Center for Solid and Hazardous Waste Management, a statewide research center hosted by the UF College of Engineering.
“What’s important for people to realize is that arsenic is relatively mobile, so it’s something we have to be relatively concerned about – how to manage this huge stock of CCA wood that remains to be disposed of,” said Tim Townsend, a UF associate professor of environmental engineering.
Earlier studies on the arsenic leaching problem prompted the wood products industry to phase out CCA-products for residential use in 2003, but CCA-wood can still be used in utility poles and industrial timbers.
Helena Solo-Gabriele, a professor of environmental engineering at the University of Miami, Townsend and their colleagues studied rainwater runoff from a CCA-treated deck for a year. Their conclusion: Arsenic contamination was 100 times higher than runoff from an untreated deck.
Not only that, but a layer of sand underneath the deck had arsenic levels 15 to 30 times higher than background levels, while water that percolated through the sand also was contaminated by the toxic metal.
“Only a small fraction leaches in any given year,” Solo-Gabriele told Environmental Science & Technology Online News, the journal’s news section. But because the wood can be in the ground for several years “the impacts can be significant, especially given the high concentrations of arsenic in the wood itself.”
The researchers concluded that by 2000, Florida had imported 28,000 metric tons of arsenic, 4,600 of which have already leached into the environment, according to one of their papers. They predicted that as much as 11,000 additional tons of arsenic will leach from decks and other structures in the next 40 years.
That suggests that managers may want to carefully consider what should be the final resting place for CCA-treated wood that has been taken out of service, Townsend said.
“These estimates provide decision-makers with information that helps them decide whether or not CCA-treated wood should go into lined or unlined landfills,” he said.
Unfortunately, however, that won’t end the problem. A mathematical model based on the researchers’ experiments estimated that between 20 and 50 tons of arsenic may have leached into construction and demolition landfills in Florida before 2000, with an expected increase of between 350 and 830 tons of the heavy metal by 2040.
Florida law does not require that construction-and-demolition landfills be equipped with linings. Although there isn’t yet much evidence of groundwater contamination in monitoring wells around those landfills, that could well become a problem, said John Schert, director of the Florida Center for Solid and Hazardous Waste Management.
“The leaching research conducted by the team suggests that arsenic contamination of the groundwater under these landfills may be a large future problem that future generations have to deal with,” Schert said.
One possible solution is to require linings, Schert said. However, that might put many of the landfills out of business.
“This would probably lead to much more illegal dumping of construction-and-demolition waste in remote, rural and agricultural locations,” he said. “Illegal dumping of construction and demolition waste in Florida is already a big problem.”
ConsumerAffairs.Com. Dangers of Treated Wood Documented
February 10, 2003
A report prepared for the Consumer Product Safety Commission (CPSC) warns that millions of children and adults face an increased risk of bladder and lung cancer from playing and eating on wooden playground sets and decks.
It is the first formal acknowledgement by a federal agency that there are serious healthy risks assciated with the pesticide-treated wood that’s been in common use in playgrounds and rential dec since the 1970s. The pesticide used to repel termites and other pests contains a form of arsenic, a known carcinogen, which “bleeds” from the wood. It is being phased out beginning next year but its effects will be felt for years.
The report estimates that from 2 to 100 individuals per one million will get bladder or lung cancer from their exposure to the arsenic. Children are at the most risk of exposure, since they are more likely to put their hands in their mouths after touching the wooden surfaces.
They cancers generally take decades to develop so many of those exposed as children will not become ill until they are adults.
The report recommends that parents require their children to wash their hands after playing on wooden playground sets and recommends that eating be discouraged on our near arsenic Treated wood.
Nearly all wooden decks, landscaping timbers and playground sets are treated with the arsenic-containing substance. Cedar and redwood resist rot and termite infestation without being treated but they are not used as frequently because of their much higher cost.
The CPSC and Environmental Protection Agency (EPA) are testing various sealants that might be used to make existing structures safer.
The CPSC will use the scientists’ report to consider whether additional safety measures should be taken. Recommendations could range from regular applications of sealant to removal of existing playground sets.
In the interim, there are several steps consumers can take to minimize risks from arsenic-treated wood:
Don’t Burn It. Wood used as landscaping timbers, fence posts or in decks and playgrounds should never be burned in a fireplace, furnace or outdoor fire, as burning releases arsenic into the air, water and soil. Consumers should contact local government agencies to find out how to dispose of the wood.
Require that children wash their hands after playing on wooden playground sets.
Don’t serve food on or around treated wooden structures.
If buying wood for a construction project, check with the manufacturer to ensure that it is free of arsenic. Consider using cedar or redwood instead.
If buying playground equipment, consider using aluminum structures.