A quantitative and nondestructive method for determining the degradation of waterlogged archaeological wood

Abstract

Archaeological artifacts are an essential part of preserving history and culture, and can be valuable tools for enhancing education and contributing economic benefits through tourism. Of the artifacts that one may encounter, waterlogged archaeological wood is one of the most difficult materials to conserve. Without knowing the level of degradation of the wood, conservators cannot properly stabilize and conserve the waterlogged archaeological wooden artifact. Currently, an established method commonly used to determine the level of degradation of waterlogged archaeological wood is the pin test. Alternative and more quantitative methods are destructive, expensive, time consuming, and not readily available to archeologists or conservators. An analytical method that can quantitatively determine the degradation level accurately in order to properly stabilize and conserve the waterlogged archaeological wood would be a valuable tool for a conservation specialist. The main goal of this project was to develop such a method. Lignin was chosen as the primary component of analysis in this study, since it is the last structural component within wood to degrade. Determining the concentration of lignin will result in a more quantitative measure of the degree of degradation. Preliminary infrared data revealed a trend in lignin concentrations confirming that infrared spectroscopy has the potential to quantitatively determine the degradation of waterlogged archaeological wood. Two gravimetric methods were utilized to obtain percentages of lignin concentration within tongue depressors and compared to create an improved gravimetric analysis. The lignin quantities found from the modified gravimetric analyses were used as reference data with infrared spectroscopy so that known quantities of lignin may be compared with and verify the spectroscopic results. If the concentrations of lignin obtained by infrared spectroscopy are confirmed by the improved gravimetric analysis results, then a new nondestructive and quantitative method to determine the level of degradation of wooden waterlogged artifacts will only take minutes rather than weeks.