From January 5, 2006
Arsenic-Treated
Wood Poses Long-Term Environmental Hazard
(Beyond Pesticides, January 5, 2006) A
recent study
by researchers from the University of Miami, the University of Florida,
and Florida International University finds that arsenic leached from
treated lumber enters the environment through rainwater runoff, contaminating
soil and threatening groundwater sources, according to a press
release. The arsenic is leached from chromated
copper arsenate (CCA), a preservative for wood used in decks, utility
poles, and fences.
The researchers found that arsenic contamination was a hundred times higher in rainwater runoff from a treated deck than from an untreated deck. Furthermore, a layer of sand underneath the treated deck had arsenic levels 15 to 30 times higher than normal, and the water that passed through the sand was also contaminated.
Long-term exposure to arsenic has been shown to amplify the rate of mutations in humans, increasing cancer and birth defects. It also has been linked with peripheral nervous system disturbances and degeneration, hearing loss, and immune system suppression.
Earlier studies on the danger of CCA-treated wood prompted its phasing-out for residential use in 2002 (see Daily News Article 02/13/02) but it is still used in utility poles and industrial timbers. While only a small fraction of the arsenic leaches over the course of a year, the long-term environmental impact can be significant given the extended period that the wood is in the ground.
The researchers determined that by 2000, Florida had imported 28,000 metric tons of arsenic, 4,600 of which have already leached into the environment. They predict that as much as 11,000 additional tons of arsenic will leach from decks and other structures in the next 40 years.
The disposal of CCA-treated wood in landfills is also a concern. It is usually dumped into landfills, where it continues to leach arsenic that can then enter into groundwater. It is estimated that between 20 and 50 tons of arsenic have leached into construction and demolition landfills in Florida before 2000, and an increase of between 350 and 930 tons of arsenic by 2040 is predicted.
One way this environmental contamination can be reduced is by disposing CCA-treated wood into lined landfills that prevent leached arsenic from entering the groundwater. Linings are not currently required for landfills by Florida law. However, there is concern that requiring linings would put many landfills out of business and promote illegal disposal.
TAKE ACTION: For more information on the dangers and alternatives to wood preservatives, as well as measures to take to prevent possible harm see our wood preservatives page. Urge your utility company to stop the use of CCA-treated utility poles, and replace those that people come into contact with in home yards, school yards, and in other places in the community where people, especially children, come into contact with the wood. If you are worried about exposure to wood preservatives, you can test soil around treated wood structures for dangerous levels of arsenic.