Leaching of CCA preservative from treated timber in marine environment

IRG/WP 01-30254

M V Rao, V Kuppusamy, K S Rao, L N Santhakumaran

Knowledge on the amount of preservatives leaching out of treated wood is essential to optimise the chemical loading in various species of timber required for different end uses. In order to gain more insight into this aspect, the residual CCA content in 40 treated timber panels belonging to 14 species removed on destruction by marine organisms from a series of durability tests conducted in Kochi waters (west coast, India) were estimated. The data showed that CCA enhanced the durability of various timber species to different degrees. In the case of panels treated to lower loading, the average annual leaching of CCA ranged from 0.36-2.81 kg.m-3 and that in specimens subjected to higher loading from 0.54-4.99 kg.m-3. The leaching rate was found to be relatively slower in panels with higher loading than that with lower loading. In general, the leaching rate of CCA was seen varying among panels of different species, panels with identical initial preservative content and even among various panels within a species. The study thus suggests the requirement of in-depth field studies into the various aspects governing the leaching phenomenon of preservatives used under marine conditions to arrive at appropriate conclusions.


Keywords: WOOD PRESERVATIVES; CCA; LEACHING; MARINE ENVIRONMENT; TREATED WOOD; DURABILITY

Conference: 01-05-20/25 Nara, Japan


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