Effect of post-treatment steaming on preservative migration from pentachlorophenol-treated wood

Abstract

Pentachlorophenol (PCP) remains important in North America for protecting industrial products from deterioration. One negative of PCP use is that some chemical is solubilized when wood is wetted, raising concerns about non-target organism risks. Best Management Practices (BMPs) were developed to reduce PCP migration and are increasingly used, but there are few data demonstrating their efficacy. The effect of post-treatment steaming or hot water immersion on PCP losses was studied on southern pine and spruce-pine-fir-treated lumber. One hour of steaming had minimal effect on PCP migration, while prolonged steaming markedly reduced losses. Hot water immersion was less effective than steaming, but better than no BMP process. BMP effects remained with a second wet/dry cycle. The results illustrate the benefits of BMPs. While not used outside North America, PCP may serve as a model for limiting migration of other less water-soluble preservatives dispersed in petroleum solvents.