Chemical Changes in CCA Treated Wood

When the chromium, copper or arsenic present in CCA-treated wood leach into soil or aquatic environments they may undergo a variety of chemical reactions and change form, a process known as speciation. Environmental factors such as pH, temperature, the amount of water, and the type of soil present can determine whether and how speciation occurs. The final chemical form can affect how easily the chemicals move around in the environment and their toxicity. Some forms of arsenic, for example, are more likely to move through soil and contaminate groundwater. It's important to consider the speciation process when evaluating any potential risks CCA-treated wood may pose to humans or the environment.

If you have questions about CCA, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email us at npic@ace.orst.edu.

Additional Resources:

• Environmental Issues on the use of CCA treated wood - Connecticut Agricultural Experiment Station
• Arsenic Toxicological Profile - Agency for Toxic Substances and Disease Registry (ATSDR)
• Arsenic Speciation of Solvent-Extracted Leachate from New and Weathered CCA-Treated Wood - Khan et al., 2004; Environmental Science and Technology
• Release of Arsenic to the Environment from CCA-Treated Wood. 1. Leaching and Speciation during Service - Kahn et al., 2006; Environmental Science and Technology
• Implication of Chromium Speciation on Disposal of Discarded CCA-Treated Wood - Song et al., 2006; Journal of Hazardous Materials

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