Environmental Impacts
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Marine Waters
There is less literature and information available regarding CCA-treated timber impacts on marine wasters, where it is most commonly used for marine piles. Townsend et al (2003) found that copper, rather than arsenic, was most toxic for the aquatic environment. However, when copper was present in the CCA combination, it appeared to be more toxic than when it was on its own, raising concerns about the effects of the combination of copper, arsenic and chromium.
Weis and Weis (2004) point out that the “deleterious effects” of CCA-treated timber on many aquatic organisms have been well documented. The heavy metals, particularly the copper, accumulates in the sediments near the wood and in the organisms, particularly those that live in the sediments or attach themselves to the wood. The metals can then bioaccumulate up the food chain. Impacts include reduced growth, altered behaviour and mortality at the individual level, and reduced numbers and diversity at the community level. They note that any alternative preservative to CCA would still be harmful to an aquatic environment if it contained copper.
Initial research findings from the CSIRO into bio-acculumation of CCA in barnacles has found that barnacles on CCA-treated marine piles have elevated heavy metal levels, although barnacles on adjacent untreated piles do not have elevated levels. Barnacles on piles treated with CCA then sealed in by creosote have not been found with elevated levels of arsenic, although they do have slightly higher levels of copper (Cookson, L., CSIRO Forestry and Forest Products, Pers. Comm., 14/12/04).
References:
Townsend, T., Stook, K., Ward, M., Solo-Gabrielle, H. (2003) ‘Leaching And Toxicity Of CCA-Treated And Alternative-Treated Wood Products’, Florida Center For Solid And Hazardous Waste Management, Report #02-4
Weis, J.S. and Weis, P. (2004), ‘Effects of CCA Wood on Non-Target Aquatic Biota’, Environmental Impacts of Preservative-Treated Wood Conference, Orlando, February. http://www.ccaresearch.org/Pre-Conference/pdf/Weis.pdf