EPA Evaluation and Interpretation of the Draft Final Baseline Ecological Risk Assessment (BERA) for Portland Harbor

1. EPA Evaluation and Interpretation of the Draft Final Baseline Ecological Risk Assessment (BERA) for Portland Harbor Burt Shephard U.S. Environmental Protection Agency Seattle, WA Presented at the Portland Harbor Cleanup and Restoration Conference Portland, OR May 4, 2012

2. Objectives of This Presentation • Present EPA’s evaluation and interpretation of the draft final BERA for Portland Harbor • Describe the risk assessment process that led EPA to its interpretation of results • Create awareness of issues involved in presenting the BERA results in a manner usable to risk managers and decision makers as they make remedial decisions in the feasibility study • Make clear the difference between risk assessment and risk management • Heckling bait for the already expert

5. Boundaries of the BERA • September 2001 – Statement of Work attached to the Administrative Order on Consent identified an in-water initial study area between river miles 3.5 and 9.2 on the Willamette River • 2007 – Programmatic Work Plan developed for the Lower Willamette Group (LWG) expanded the in-water study area to between river miles 1.9 and 11 • Present day – BERA evaluates in-water ecological risks between river miles 1.9 and 11.8 • Upland soil defined in conceptual site model of the BERA problem formulation as the terrestrial areas higher in elevation than Ordinary High Water Mark • BERA does not evaluate fully terrestrial receptors

6. What Was Evaluated in the BERA? • Assessment Endpoints – Explicit expressions of environmental values to be protected • Described as survival, reproduction and growth of . . . • Aquatic plants • Benthic invertebrates • Bivalves • Decapods • Invertivorous fish • Omnivorous fish • Piscivorous fish • Detritivorous fish • Amphibians • Piscivorous birds • Omnivorous birds • Invertivorous birds • Aquatic-dependent mammals

7. Example BERA Assessment Endpoint from Portland Harbor Target ecological receptors – species chosen as representative of other similar species Measurement endpoints – measurable ecological characteristics related to the assessment endpoint Line of evidence – a set of data and its associated analyses that can be used, either alone or in combination with other lines of evidence to estimate ecological risks

8. Overall, the BERA Contains . . . 13 assessment endpoints 31 measurement endpoints Toxicity testing of sediment and water Surface water contaminant concentrations Transition zone contaminant concentrations Sediment contaminant concentrations Tissue concentrations Ingested dietary dose of contaminants 59 lines of evidence Toxicity tests with multiple species, survival and biomass endpoints Sediment chemistry benchmarks from both literature and site specific modeling efforts Tissue concentrations were both measured and predicted from food web models Dietary doses estimated from measured prey contaminant concentrations and measured contaminant levels in stomach of predator species

9. What Did We Find Out? • 4 lines of evidence with no unacceptable risks • 105 chemicals with at least one sample with hazard quotient of HQ ≥ 1.0 • Because of the availability and definition of toxicity reference values (e.g. Total PCB and Aroclor 1254 TRVs or 4,4’-DDT and Total DDTs TRVs, etc. for different LOE), total number of chemicals and groups of chemicals with HQ ≥ 1.0 closer to 90 once the various related TRVs are combined • Highest hazard quotients are found in transition zone water (cyanide, insecticides, PAHs) or in surficial sediments (PAHs, DDT) • Highest TZW HQ = 4400 for cyanide • Highest sediment HQ = 4800 for acenaphthene using PEL • Greatest number of chemicals posing potentially unacceptable risks also in TZW and sediments

10. What Did We Find Out? • Surface water, tissues, dietary ingestion HQs tend to be lower than TZW and sediment HQs, risks identified for fewer chemicals • Nearly 60 chemicals have HQ ≥ 1.0 in only one line of evidence, often TZW chemicals • No single chemical appears to be a risk at all locations in the site • Instead, individual chemical risks are localized in one or more areas, with spatial gaps of low risk between areas of higher risk • PAHs, PCBs and total DDx are the chemicals with the most widespread risks • PCBs, Cu, Total TEQ TBT, Zn, DDx and PAHs pose risks in the largest number of lines of evidence

11. Data Interpretation Issue The ideal world The Portland Harbor world Sediment quality benchmark Sediment quality benchmark Nontoxic Toxic Nontoxic Toxic Sediment chemical concentration > Sediment chemical concentration > Easy to define a sediment concentration that reliably separates toxic from nontoxic samples No SQB or model, no matter how good it is, will be able to reliably separate toxic from nontoxic samples Now try defining reliable SQBs for each of the 40 chemicals potentially posing risks in sediment with this much overlap!

12. What if SQB is Lower or Higher than Optimal? Risk assessment Risk management Sediment chemical concentration > Sediment chemical concentration > SQB is low: Few false negatives, but many false positives. SQB is high: Few false positives, but many false negatives.

13. PCB in Sediment Concentrations at Locations with Co-Occurring Toxicity Tests Proportion of total samples Total PCB, µg/kg dw Toxicity data for Chironomus biomass severe toxic effects

14. What if We Let the Organisms Themselves Tell Us About Risks?Sediment Toxicity Test Results Table values are number of stations out of 293 eliciting the given level of toxicity and (proportion of total number of samples eliciting toxicity) Chironomus dilutus – 10 day survival and biomass Hyalella azteca – 28 day survival and biomass Strongest lines of evidence in the entire BERA

15. Areas Within the Site Predicted to Reduce Chironomus Biomass – BERA Evaluation

16. Areas Within the Site Predicted to Reduce Chironomus Biomass – EPA Evaluation

17. Problems With Previous Two Maps We know there is more of the site eliciting toxicity than the locations identified by dots We also know that the GIS natural neighbor interpolation of the EPA map likely overestimates the site area eliciting toxicity Due in part to the paucity of toxicity test stations mid-channel So how do we describe to risk managers the proportion of the site that elicits unacceptable levels of toxicity? Better mapping procedures At some point during remedial design, additional samples will need to be taken to better bound locations undergoing remediation

18. Anthracene in Sediment Mapped Two Ways Top – Contours generated for three segments: east bank, west bank, center channel Bottom – Mapped across entire river as one segment

19. Summary Table(s) of BERA Results

20. End Product of Ecological Risk Assessment Should Answer the Following Questions for All Chemicals with HQ ≥ 1.0 • Which ecological receptors are at risk? • What chemicals pose unacceptable risks? • What are the magnitudes of the unacceptable risks? • What are the uncertainties associated with the risk estimates? • Uncertainties can result in both overestimation of risks (e.g. TRVs are overly conservative for site receptors), and • Underestimation of risks (e.g. many chemicals do not have TRVs, thus risks cannot be quantified) • Where within the site are areas of unacceptable risk found?

21. And Present a Protective Concentration Range for Chemical Posing Potentially Unacceptable Risks • Give managers guidance on cleanup numbers protective of ecological receptors • Often described as a threshold for effects on the assessment endpoint as a range between concentrations posing no ecological risk and the lowest contaminant concentrations identified as likely to produce adverse ecological effects • Because different receptors have differing sensitivities to contaminants, there will be a range of protective concentrations • All ecological risk benchmarks potentially useful as cleanup numbers at Portland Harbor exceed their respective background concentrations

22. Sediment Preliminary Remediation Goals (PRGs) Calculated from 1st Draft BERA

23. Difference Between Risk Assessment and Risk Management • To this point (end of Step 7), the 8-step EcoRA process has been based on scientific and technical analyses • Step 8 involves risk management • Risk assessment – establishes whether a risk is present, defines a range or magnitude of the risk and its uncertainties • Risk management – results of the risk assessment are integrated with other considerations to make and justify management decisions

24. Superfund 8 Step EcoRA Process: Step 8 – Risk Management • Done by risk managers, not risk assessors (I don’t get to pick the final cleanup values) • Evaluates several factors in addition to ecological risks (e.g. human health risks) before deciding whether to clean up within range defined in Step 7 • Scientific management decision point #6 – Risk management decision finalized, described and justified in Record of Decision for the site • EPA requested that LWG provide their ecological risk management recommendations in a separate chapter at the end of the BERA • EPA’s ecological risk team will make its risk management recommendations in a standalone technical memorandum

25. Differing Goals of Risk Assessment and Risk Management • Risk assessments are informational • Risk management is decisional

26. Questions? Shephard.Burt@epa.gov