Modeling of wood preservative leaching in service

To evaluate the potential environmental and health implications of leaching of wood preservatives in service under different conditions, there is a need for a predictive model that provides estimates of the rate and extent of leaching over a wide range of exposure conditions. In this paper, we test the hypothesis that preservative component emissions can be modeled on the basis of three easily measured parameters: total leachable component based on intensive leaching of fine ground material; amount of dissolved or dissociated component in water saturated wood; and preservative component diffusion coefficients in the longitudinal and transverse directions. These variables are estimated for ACQ, copper azole, CCA and borate wood preservatives and the leaching rates of lumber samples are compared with the rate predicted by the model. This model approach should permit the estimation of leaching rates under a wide variety of product geometries and exposure conditions.