In Search of the Smoking Gun: Linking Environmental Contamination to its Source

Marthe Monique Gagnon, Alan G. Scarlett, Curtin University; Francis D. Spilsbury, University of Gothenburg

Contamination of the environment may cause environmental and social issues that need to be rectified and are often costly. Under the ‘polluter pays’ principle, identifying the source of the contamination is a critical first step from a legal perspective. Similarly, in order to prevent further contamination, the source must first be correctly identified. To achieve this, some form of forensic ‘fingerprinting’ is required. Multiple techniques may be required to build a ‘weight of evidence’ to identify the source. In this session, we encouraged the presentation of studies successfully linking contamination with its source. We also encouraged presentation of novel methods that show promise of delivering improvements to existing techniques or original methods that provide new opportunities.

The session attracted a variety of presentations, and included:

• Steve Roland, University of Plymouth, walked us through the identification of a mystery substance repeatedly spilled in UK coastal waters, resulting in a legal re-classification of the potential hazards associated with polyisobutene (PIB) transport by sea.
• Alan Scarlett, Curtin University, used diamondoids accumulated in fish to forensically fingerprint oils. This research showed that indices derived from crude oils and fish adipose extracts have an excellent linear fit, making diamondoids strong candidates to relate exposure of fish to source oils.
• The source of polychlorinated biphenyls in rivers was identified in Switzerland and France by Ines Tascon, University of Lausanne, using environmental concentrations, load and chemical signatures, providing support to authorities in order to prevent current chemical releases from being continued.
• A high frequency monitoring of the river Rhine has the potential to inform drinking water plants of contamination events potentially affecting water quality. The research by Teofana Chanova, Swiss Federal Institute of Aquatic Science and Technology, showed that high-frequency monitoring, in combination with advanced data science tools, can provide key information for river surveillance and management.
• Behavioral fingerprinting also showed promises in providing better understanding the relationship between behavior of invertebrates being exposed to a contaminated effluent and known sources of contamination. George Ruck, National Research Institute for Agriculture, Food and Environment, reviewed the results that showed naturally occurring spikes in micropollutants matched behavioral fingerprints of the tested organisms.

The associated poster session also attracted presentations that highlighted the importance of using multidisciplinary approaches to relate contamination to its source. Contamination by crude oils appears to be a current topic with bicyclanes accumulated in fish tissues being shown to be the almost perfect candidates to relate a crude oil to its source. The recently introduced Low Sulphur Fuel Oils involved in the Mauritius oil spill (2020) was highlighted by the identification of steranes and hopanes in sediments collected on site, relating contamination to the source oil of the MV Wakashio. In addition, tar balls collected along the coast of the Netherlands and Belgium were analyzed for fingerprinting, and along with oil spill modeling the source of these tar balls was successfully identified.

Other posters focused on a variety of approaches:

• Analysis of 600 years of sediment cores were able to trace back various fires and wars around human settlements.
• Air samplers associated closely the chemical fingerprint between indoor and outdoor environments in areas receiving industrial airborne chemical emissions.
• Polar organic micropollutants were monitored using hydrophilic samples as a basis to guide future monitoring campaigns in polar regions.
• Temporal PFAS trends were studied, and results highlighted the utility of a multi-analysis approach to characterize temporal PFAS trends in sediments.
• A groundwater toolbox is being developed as a powerful tool for evaluating groundwater health and identifying residues of concern in food production areas.
• A study on wastewater treatment works showed a significant impact of effluent discharge into a river on some common water quality parameters but the trace contaminant concentrations in river waters were poorly related to the discharge.

Overall, the session highlighted the importance of chemical fingerprinting in various matrices using multidisciplinary approaches. By successfully identifying the ‘smoking gun’, the polluter can be held responsible for their actions and the environment will be better protected in the future.

Author’s contact: [email protected]