Institute for Transportation

Creosote has a long history of use as a preservative, particu-larly in industrial wood products. However, its use has come under increasing scrutiny as a result of concerns about ptential effects on aquatic and terrestrial non-target organ-isms. Despite the long use of creosote, there is relatively little data on the rates of creosote loss in many exposures, including aquatic applications. To address this concern, the Federal Highway Administration has funded a series of studies to evaluate the environmental impact of creosote-treated wood used in timber bridges. In the study reported here, we investigated the leaching of creosote from rough-sawn Douglas-fir lumber under simulated river flow condi-tions. Treated wood samples were contained in a metal tank, and deionized water was passed through the box at three predetermined flow rates and temperatures. The water was periodically sampled for the concentration of five major creosote components. The leach rates were highly variable, but in general they tended to increase with both flow rate and temperature. The possible onset of turbulent flow in the tank may have been responsible for the high leach rates observed at high flow rates. In general, the rates of leaching determined in this study were greater than those previously reported for creosote-treated piling. Longer exposures may be needed to better predict creosote release rates during decades of in-service use.

Keywords: Creosote, leaching, solid phase microextraction, acenaphthalene, dibenzoquinone, fluorene, fluoranthene, phenanthrene, pollution.