1. Providing Expert Opinion to Support Environmental Litigation
Joel van Popta April 27, 2018

2. Outline Purpose of Opinion Evidence Duty of an Expert
Perception of Bias
Maintaining Objectivity
Facts / Evidence
Case Study
Summary
Questions?

3. Purpose of Opinion Evidence

4. Purpose of Opinion Evidence
Explain complexity
Do not unnecessarily increase the complexity
Work within your area of expertise
Scope of work outlined in retainer letter

5. Duty of an Expert

6. Duty of an Expert
Form 53 (Acknowledgment of Expert’s Duty)
I acknowledge that it is my duty to provide evidence in relation to this proceeding as follows:
to provide opinion evidence that is fair, objective and non-partisan;
to provide opinion evidence that is related only to matters that are within my area of expertise; and
to provide such additional assistance as the court may reasonably require, to determine a matter in issue.
I acknowledge that the duty referred to above prevails over any obligation which I may owe to any party by whom or on whose behalf I am engaged.

7. Duty of an Expert
Civil action, not criminal
Making conclusions / judgements on the balance of probabilities, not “beyond all reasonable doubt”
What is the most plausible and reasonable outcome from a certain set of circumstances?

8. Perception of Bias

9. Perception of Bias
Bias: prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair
Do not become overly sympathetic to your client
Association bias
Not about ‘winning’

10. Maintaining Objectivity

11. Maintaining Objectivity
Difficult to maintain if involved in a file for a long time.
Remain dispassionate when responding to a rebuttal report
Bounce ideas off colleagues
Be wary of clients pushing for a certain outcome
You are not an advocate, that is the lawyer’s job

12. Facts / Evidence

13. Facts / Evidence
Provide an opinion based on accurate, discernable facts
Don’t guess or speculate
Provide explanations based on facts that clearly articulate the most persuasive and plausible explanation
If using assumptions, are they reasonable?

14. Opinion of Contaminant Migration
Case Study
Opinion of Contaminant Migration

15. Background Residential fuel oil release AST located in basement
Gravel floor over bedrock
Basement recessed into bedrock
Close proximity to neighbours
Slow leak over a number of months
100 L to 400 L release volume

16. Stratigraphy / Hydrogeology
+/- 1 m overburden – silty sand
Weathered limestone bedrock to 4 m.
Shale seams within weathered limestone interval
Competent limestone bedrock beyond
Shallow groundwater in weathered bedrock

17. Scope of Work
Stantec was asked to review assessment and remediation reports prepared by others and respond to the opinion of another consultant associated with the following:
possibility of historical impacts
multiple sources of hydrocarbon
size of the contaminant plume

18. Facts / Evidence
Volume of 100 L to 400 L fuel oil over a period of up to one year
Shallow groundwater approximately 0.5 m below release point
Groundwater elevation higher under house than neighbouring properties
Dominant flow path within weathered bedrock
Liquid product and highest dissolved concentrations near loss location
No forensics on liquid product or review of chromatograms

19. Conclusions
No evidence in the reporting record of a forensic evaluation that assessed either the degree of contaminant weathering or assessed certain contaminant characteristics in different parts of the plume that could address whether multiple sources existed.
Groundwater monitoring and sampling by others demonstrated that free-phase petroleum hydrocarbon (PHC) was present near the point of loss, and concentrations of PHC parameters in groundwater decreased away from the point of loss
No evidence of multiple PHC sources
Migration away from point of loss was through fractured bedrock. The size of the plume is not unreasonable.

20. Summary

21. Summary Explain Complexity Duty to the Court
Remain unbiased and maintain objectivity throughout the file
Articulate a clear fact-based opinion that supports the most plausible explanation

22. Questions?