Terms of Reference

Towards the Development of Toxicity Standard Methods to Evaluate Biological Effects of Heavy Oils on Aquatic Ecosystems

National Peer Review—National Capital Region

January 31 to February 2, 2017
Ottawa, Ontario

Co-chairs: Gilles Olivier and Judith Leblanc

Context

In light of increasing oil and gas resource development in Canada, there is increased potential for aquatic contamination resulting from both routine operations and accidental releases. Given that heavy oils can have deleterious effects on aquatic biota, it is necessary to develop a framework of standard toxicity tests that will allow for more reproducible results and more valuable comparisons both across test species and across heavy oil formulations. Currently a variety of techniques are used, which makes it difficult to compare results from toxicological studies.

When evaluating the potential toxicity of accidentally released heavy oil, researchers must simulate realistic conditions of exposure that naturally occur in an aquatic environment. In order to get results that could be extrapolated to real-life scenarios, researchers must take into account that oil will be diluted once spilled in water and that its properties will be changing with sea conditions and time. For accuracy, these elements must be reflected in the design of the toxicity studies.

Chemical Response to Oil Spills—Ecological Effects Research (CROSERF) is the most commonly applied method for the preparation of oil and the development of exposure protocols for heavy oil formulations. This method, developed in the United States, describes aquatic toxicity testing protocols with the foremost objective of standardizing test methods and reducing inter-laboratory variability. It prescribes a series of guidelines to prepare an oil sample for testing, either in the form of a Water Accommodated Fraction (WAF) or a Chemically Enhanced Water Accommodated Fraction (CEWAF). These are the most common forms in which oil toxicity can be tested.

Researchers working with heavy oils, including diluted bitumen, have tried to use CROSERF for the study of their potential toxicity. For bitumen, it was ineffective as various dilutions or solutions were needed as a result of its unique physical and chemical properties. Of particular note is its accelerated reaction to weathering resulting in a toxic by-product as well as its adhesive characteristics and higher viscosity relative to conventional heavy oils.

In consideration of the above, it is proposed to develop a Heavy Oil Toxicity Standard Methods to produce more comparable toxicity results, improve the consistency between heavy oils studies, and collect more environmentally relevant data. As WAF/CEWAF provide the most consistent results when testing heavy oil formulations produced in Canada, these new standard methods will outline the appropriate techniques for preparing these fractions and designing toxicity studies.

Fisheries and Oceans Canada (DFO)—National Contaminants Advisory Group (NCAG) facilitates external research on priority issues pertaining to the biological effects of contaminants on aquatic ecosystems, and provides evidence-based advice to departmental and external clients. The advice generated by this peer review will provide guidance leading to greater consistency in the preparation, analysis and aquatic toxicity testing of WAF/CEWAF for heavy oils. Reproducible and comparable results, both across test species and heavy oil formulations will inform decision-making related to ecological impacts of heavy oil spills.

Objectives

The overarching objective is to review existing methods to evaluate toxicity of heavy oils to aquatic species and to evaluate methods for standard toxicity tests to address effects of spilled heavy oils on aquatic organisms.

Areas of uncertainty and knowledge gaps will be identified in order to inform a research agenda for future work.

The specific objectives are to:

1. Review the different approaches and methods included in the Working Paper, “Review of Standard Reference Methods for Evaluating the Toxicity to Aquatic Organisms of the Water Accommodated Fraction (WAF) and Chemically Enhanced Water Accommodated Fraction (CEWAF) for Dilbit and Other Relevant Heavy Oils”;
2. Discuss advantages and disadvantages of preparation of water exposure media, with a focus on WAF and CEWAF;
3. Review the elements to be considered in the development of toxicity standard methods and consider how this fits into the overall approach of toxicity testing with a wide variety of oils, including limitations, the types of questions that can be addressed by the framework (i.e., setting the boundaries of what you want to test), and best approaches for different types of testing.
4. Identify knowledge gaps and research needs.
5. Identify the next steps towards a “Heavy Oil Toxicity Standard Methods”.

Expected Publications

• Proceedings
• Research Document
• Science Advisory Report

Expected Participation

• Experts from federal and/or provincial organizations
• Academia or Academics
• Oil and Gas Industry Experts
• Environmental non-government organizations

References

Dupuis, A., and Ucan-Marin, F. 2015. A literature review on the aquatic toxicology of petroleum oil: An overview of oil properties and effects to aquatic biota. DFO Can. Sci. Advis. Sec. Res. Doc. 2015/007. vi + 52 p.

DFO. 2015. Proceedings of the national peer review workshop on identifying research requirements for the biological effects of oil and gas-related contaminants on aquatic ecosystems; March 26-27, 2014. DFO Can. Sci. Advis. Sec. Proceed. Ser. 2015/002.