Leaching of CCA from Treated Wood

Chromium, copper and arsenic can leach into soil or water when wood treated with chromated copper arsenate (CCA) is exposed to the environment. Many factors can affect the amount of leaching that occurs from treated wood. Such factors include how long the wood has been exposed to the environment, the size and type of wood that was treated, whether the wood is coated with a sealant, water movement, and the type of soil. The chemicals that leach from CCA-treated wood can accumulate in soils near the wood, but under certain conditions, the chemicals can travel farther. In general, CCA chemicals are least mobile in organic soils, slightly more mobile in clay soils, and most mobile in sandy soils or water.

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
• CCA-Treated Wood - Agency for Toxic Substances and Disease Registry (ATSDR)
• Leaching of Wood Preservative Components and Their Mobility in the Environment - USDA Forest Products Laboratory
• Environmental Impact of Treated Wood in Service - USDA Forest Products Laboratory
• Metals concentrations in soils below decks made of CCA-treated wood - Florida Center for Solid and Hazardous Waste Management
• Rate of CCA leaching from commercially treated decking - Forest Products Laboratory
• Copper, chromium, and arsenic in soils under decks built from treated wood - Connecticut Department of Public Health
• Does Arsenic Leach From Pressure Treated Wood Used in Docks & Pilings, and Is This a Health Concern? - Connecticut Department of Public Health

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