Several Canadian treating plants are using moderate temperature (40-60C°) fixation chambers to reduce drippage and leaching from fresh CCA treated wood. In this study, chromium reduction and surface leaching properties of CCA-C treated red pine (Pinus resinosa) pole sections were monitored during exposure to temperatures of 50-60C° and 90-100% RH conditions. Chromium-VI concentration in the absorbed treating solution dropped significantly during the treating cycle to 50-60% of that in the free treating solution. The chromium-VI concentration also dropped with increasing depth in the pole. During the six to 24 hour fixation cycle the Cr-VI concentration dropped steadily especially in the outer layers of the pole, but even after 6 hours, a significant amount of Cr-VI was observed at all measured depths. After 12 hours, Cr-VI was only barely detectable at all depths. The leachate analyses were consistent with the Cr-VI results, indicating reduced but still significant surface losses while Cr-VI could still be detected.

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