Arsenic in Our Dining Tables?
Chromatid copper arsenate is a wood preservative invented by Santi Kamesam in 1933. The preservative contains a mixture of Chromium, copper and arsenic. Chromium is used to bind the copper and arsenic to the wood, copper “acts as a fungicide”1 and arsenic has preservative and insect deterring properties. The Chromatid copper arsenate preservative has been used “for over 60 years to increase the expected lifetime of”2 wood products. Chromatid copper arsenate (CCA) is used to pressure treat wood all over the world to prevent rot and deter insects. Until recently, it was the most popular wood preservative being used for commercial and residential purposes. “Most pressure treated wood in the U.S. is CCA wood.”3 Not only is CCA treated wood a health concern for children who play on wooden play structures that are contaminated with arsenic, but also the leeching effects that take place on these structures leads to contaminated groundwater and soil. Also, the possibility of arsenic being dispersed into the air when a wooden CCA-treated structure catches fire is another concern. The problem with using arsenic is the fact it is a group 1 carcinogen, which can cause cancer and other serious diseases.
Since its invention in 1933 up until 2003, CCA treated wood has been used everywhere from children’s play structures to houses, decks, bridges and barns. Even though as mere CCA-treated wooden structures, they might not pose any threat, but if these structures are burned, destroyed or left abandoned the ramifications could be severe. For example, in 2005 when Hurricane Katrina hit New Orleans and destroyed millions of homes the resulting devastation of wooden homes left an “estimated 1740 metric tons of arsenic disposed.”4 Children are most at risk, because after playing on CCA treated wood they are likely to put their hands in their mouths, which can expose them to high concentrations of arsenic. A study done in Florida discovered that beneath CCA treated wooden structures the soil becomes contaminated with high concentrations of arsenic. “65 surface soil samples collected from below CCA-treated structures were 28.5 mg/kg”5 of arsenic. In all 65 samples the concentrations were above Florida’s risk limit.
In 2003, the United States EPA and the lumber industry began to phase out the use of the toxic preservative for most residential purposes “in favor of new alternative wood preservatives.”6 The EPA said, “no wood treater or manufacturer may treat wood with CAA for residential uses, with certain exceptions.” This does not include industrial uses of CCA-treated wood, which could still be a cause for concern. Also, existing structures made form CCA-treated wood are allowed to remain intact as demolishing them could increase arsenic exposure. There are viable alternatives to both preservatives and materials used to create structures, which would eliminate the need to use arsenic in either. Another issue is the disposal of CCA-treated wood, which is extremely difficult as it cannot be burned due to the release of arsenic into the air and soil nor is it safe to dispose in a landfill as the arsenic could potentially leak into the water supply. To limit exposure to arsenic in already existing CCA-treated wooden structures, the EPA advises to put a layer of penetrating oil to the surfaces of the wood to “lessen or eliminate human and animal exposure.”7 This should be done every year or so to prevent exposure.
References
1) "Disclaimer." Lumber Pressure Treated With Chromated Copper Arsenate. Web. 19 Mar. 2015.
2) Nico, Peter S., Scott E. Fendorf, Yvette W. Lowney, Stewart E. Holm, and Michael V. Ruby. "Chemical Structure of Arsenic and Chromium in CCA-Treated Wood: Implications of Environmental Weathering." Environmental Science & Technology 38.19 (2004): 5253-260. Print.
3) "Fact Sheet: Arsenic Treated Wood." Department of Health and Human Services. Web. 19 Mar. 2015.
4) Dubey, Brajesh, Helena M. Solo-Gabriele, and Timothy G. Townsend. "Quantities Of Arsenic-Treated Wood In Demolition Debris Generated By Hurricane Katrina." Environmental Science & Technology 41 (2007): 1533-536. Print.
5) Townsend, T., H. Solo-Gabriele, T. Tolaymat, K. Stook, and N. Hosien. "Chromium, Copper, and Arsenic Concentrations in Soil Underneath CCA-Treated Wood Structures." Soil and Sediment Contamination 12.6 (2003): 779-98. Print.
6) "Lumber Pressure Treated With Chromated Copper Arsenate." New York State. Web. 19 Mar. 2015.
7) "Pressure-Treated Wood - Its Uses, Limitations and Safety Considerations." Pressure Treated Wood Uses, Limitations and Safety Considerations. EPA. Web. 19 Mar. 2015.
