This study compares the temporal variation of chemical leaching and aquatic toxicity of wood treated with chromated copper arsenate (CCA) and other copper-based wood preservatives (alkaline copper quaternary (ACQ), copper boron azole (CBA), copper citrate (CC) and copper dimethyldithiocarbamate (CDDC)). Treated wood blocks were leached for 21 days and the leachate collected was analyzed for preservative chemicals and aquatic toxicity. The measured rate of copper leaching was fit using the recently proposed diffusion model for predicting preservative leaching rates. An unpreserved wood sample was tested as a negative control. In general the predicted values for flux rate were on the same order of magnitude as calculated using the experimental data. In natural water, several physical and chemical factors may affect the bio-availability and toxicity of chemicals. Copper concentrations and resulting aquatic toxicity obtained using two natural waters as leaching solutions were found to be lower compared with data obtained using de-ionized water as the leaching fluid.

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