Abstract
This study demonstrates the use of tricyclic and pentacyclic terpanes, trace constituents of lubricating oils, as indicators of the origin of diffuse lubricating oil contamination in plankton and sediments around St John's, Newfoundland, Canada. Different types of lubricating oils and motor exhausts were found to consistently feature distinct terpane distributions. Differences in the relative contribution of automotive and two-stroke outboard oils could be recognized in the terpane distributions of sediments and plankton from different areas. The ratio of durable pentacyclic terpanes to the size of the more labile unresolved complex mixture is demonstrated to be an indicator of the degree of weathering that oil contamination has undergone. Analysis of the terpane distributions of the entire range of refined oils and greases would enhance the use of these compounds as tracers of the sources of diffuse lubricating oil contamination.