Improved and Standardized Methodology for Oil Spill Fingerprinting

TLDR

The Nordtest methodology has served as a foundational platform for oil spill identification across Scandinavia, Europe, the USA, and Canada, and its revision is a cooperative effort among national laboratories and Battelle, drawing on extensive experience and literature in oil exploration and production geochemistry. The project aims to refine Nordtest into a more robust, defensible methodology focused on quantitative diagnostic indices and to adapt it into CEN guidelines, presenting the recommended analytical approach. The methodology is based on documented analytical improvements and a more quantitative treatment of GC/FID and GC/MS‑SIM data, incorporating operational experience from participating forensic laboratories. A recent Round Robin test involving 12 laboratories demonstrated the performance of the new methodology, with results reported in a separate paper in this issue.

Abstract

The existing Nordtest methodology for oil spill Identification has over the past 10 years formed an important “platform” for solving oil spill identification cases both in the Scandinavian countries as well as other countries in Europe, the USA and Canada. “Revision of the Nordtest Methodology for Oil Spill Identification” is a cooperative project between the National Oil Spill Identification laboratories in Norway, Sweden, Finland, Denmark and the Battelle Memorial Institute (Duxbury) in the USA. The goals of the project are: (1) to refine the existing Nordtest methodology into a technically more robust and defensible oil spill identification methodology with focus on determination of quantitative diagnostic indices (ratios) and (2) to adjust the revised Nordtest methodology into guidelines for the European Committee for Standardization (CEN). This paper presents the recommended methodology for the analytical oil spill identification part. The sampling techniques and handling of oil samples and background (reference) samples prior to their arrival at the environmental forensic laboratory is not covered in this paper. The recommended methodology approach is a result of documented analytical improvements and a more quantitative treatment of analytical data from gas chromatographic-flame ionization detector (GC/FID) and gas chromatographic-mass spectrometer methods (GC/MS-SIM) and the operational experiences over past few years among the participating forensic laboratories. The experience and literature in the field of oil exploration and production geochemistry have also played an important role for the recommended methodology. The results from a recent Round Robin test carried out among 12 laboratories using this new methodology are presented in a separate paper in this issue (8).