ABSTRACT
Lignosulfonates, which are the major organic additives in most waterbased drilling fluids discharged in the marine environment, are candidate environmental tracers of drilling fluids in marine sediments. A cupric oxide oxidation method, which is specific for the analysis of lignin-derived organic matter (e.g. lignosulfonate), was tested as part of a methodology evaluation of the use of lignosulfonate additives as drilling fluid tracers. Three lignin parameters-vanillyl phenol content, lignin composition and vanillyl acid/aldehyde ratios-were identified as the most suitable tracers of drilling mud discharges. In this study, sediments from various Outer Continental Shelf (OCS) regions were analysed to determine their lignin composition and content. The range of baseline values for the lignin parameters in OCS sediments was evaluated in relation to the potential application of the cupric oxide method in detecting inputs of lignosulfonate-containing drilling fluids in sediments of each region. The results indicate that all three lignin parameters are suitable as drilling fluid tracers, but to different extents, depending on the nature of the existing background. The three parameters exhibit different degrees of sensitivity within the sediments of any given region.
