Fixation of copper-chrome-arsenic treated timber: A comparison of leaching methodologies
S Walley, P R S Cobham, P Vinden
Five packs of kiln dried radiata pine heartwood were treated with copper-chrome-arsenic preservative treated, utilising a modified Bethell treatment schedule. Two methods of determining the level of preservative fixation were compared. These included the diphenylcarbazide method and simulated rainfall testing. The fixation levels were generally higher for tests involving simulated rain leaching. Fixation of copper-chrome-arsenic determined by the diphenylcarbazide method was found to fluctuate with time. Localised surface concentrations of preservative, 'hot spots', were suggested as the cause. Simulated rainfall appeared to provide a more realistic assessment method for determining potential preservative leaching of multisalt preservatives.