Stressor Identification Strategies: EPA Literature Review

1. An EPA Sponsored Literature Review Database to Support Stressor Identification Patricia Shaw-Allen, Ph.D. Bhagya Subramanian Susan Cormier, Ph.D. EPA, Office of Research and Development Benjamin Jessup Cathy Cresswell Tetra Tech, Inc.

2. Overview • What is Stressor Identification? • Stressor Identification = Causal Analysis • Structured, consistent strategy for identifying the cause(s) of a biological impairment • Why perform Causal Analysis? • The Causal Analysis/Diagnosis Decision System (CADDIS) home to the Causal Analysis/Diagnosis LITerature database (CADLit) Structure Data detail User interface and queries Current focus and future directions The CADLit

3. The Stressor Identification Strategy • Logically eliminate causes when you can • Diagnose causes when you can • Use strength of evidence for the rest • Do not claim proof of causation • Identify the most likely cause • Use a consistent process • Document the evidence and inferences EPA Guidance in 2000 http://www.epa.gov/ost/biocriteria/stressors/stressorid.pdf

4. Why Causal Analysis? • Causal Analysis uses biological assessment data to identify the cause(s) of impairment • In 2002, All States and several Tribes were using biological assessments for streams and small rivers. • Identified 1,440 waters with biological impairments • - representing 30,499 river miles with unknown cause(s) • TMDL Program escalates! • - TMDL lawsuits • - States need help: What are the causes of observed biological impairment?

5. Causal Analysis/Diagnosis Decision Information System (CADDIS) A web based decision support system providing information and guidance to assist State and Tribe investigators in identifying causes of biological impairments.

6. What will CADDIS Contain? • A web-based, step by step guide to Stressor Identification • Worksheets • Examples • Links 3.Analytical tools for users • Regional associations • Stressor-specific tolerance values • Conceptual model library • Web based model builder in the future and…. • Database of empirical stressor-response studies • Sediments • Toxic metals • Other stressors aka…The CADLit!

7. The Causal Analysis/Diagnosis LITerature database (CADLit) • Stores source, stressor, and response information from scientific publications • Summarizes the usefulness of each reviewed paper to SI • Documents relationships between sources, stressors, and responses • Allows investigators to query the database for relevant source, stressor, response, and location variables

8. Criteria for Data Inclusion Must be useful for Causal Analysisbysupporting at least one of the following lines of evidence: • Stressor-response (thresholds or response curves), • Association (finding association or failure to find association consistently), • Experiment – recovery or failure to recover after removal of a stressor in a real habitat or a mesocosm, • Description of mechanism of how exposures result in responses, or • Specificity of effects – evidence that an observed response can be used diagnostically

9. Strength of Evidence Considerations based on other situations or biological information Plausible Stressor Response Low dissolved oxygen has been shown to cause mortality with fish in controlled studies. DO levels at the site are at a concentration shown to cause mortality.

10. Strength of Evidence Considerations based on other situations or biological information Experiment Controlled mesocosm or field experiments demonstrate that the candidate cause can induce the observed effect

11. Strength of Evidence Considerations based on other situations or biological information Plausible Mechanism Given what is known about the biology, physics and chemistry of the stressor (low dissolved oxygen), the receiving environment, and the affected organism, it is plausible that the stressor caused the impairment and behavior of gulping air at the water surface.

12. Strength of Evidence Considerations based on other situations or biological information Specificity The impairment (jagged cut) observed in the fish can only occur from a boat propeller or other mechanical hazard. Therefore, one of these stressors must be the actual cause.

13. Database Structure Relevant publications are complex, often reporting results from multiple study designs and many environmental stressor and non-stressor parameters

14. Database Structure: Exposures

15. Database Structure: Responses

16. Data Entry

17. Response Details

18. User Interface Search for Known Associations Select specific term(s) from any category (or categories) for known associations Effects Cause/Stressor Source/ LandUse GeographicArea Associations AllKeywords

19. Source Query

20. Query Output

21. Strength of Evidence Considerations based on other situations or biological information Consistency of Association The impairment (dead fish) is observed together with the stressor () at different locations across the country.

22. Current CADLIT Focus • Peer reviewed scientific publications • Freshwater aquatic life • Priority metals (As, Cd, Cr, Cu, Pb, Hg, Se, Zn) • Clean sediments (Suspended and bedded) Future Directions • Include additional stressors in CADLit • Include grey literature (as appropriate) • Available through the CADDIS Website Proposed release: 2005 – 2006