A Regional Multiple-Stressor Ecological Risk Assessment for Port Valdez, Alaska Prepared by: Janice K. Wiegers1, Howard M. Feder2, Wayne G. Landis1, Linda S. Mortensen1, David G. Shaw2, Valerie J. Wilson1 1 Institute of Environmental Toxicology and Chemistry, Huxley College of Environmental Studies, Western Washington University, Bellingham, Washington 2 Institute of Marine Science, University of Alaska, Fairbanks, Alaska March 31, 1997 Reprinted October 2003 RCAC Contract #1033.102 A Regional Multiple-Stressor Ecological Risk Assessment for Port Valdez, Alaska Prepared by Janice K. Wiegers1, Howard M. Feder2, Wayne G. Landis1, Linda S. Mortensen1, David G. Shaw2, Valerie J. Wilson1 1 Institute of Environmental Toxicology and Chemistry Huxley College of Environmental Science Western Washington University Bellingham, WA 98225 2 Institute of Marine Science University of Alaska Fairbanks Fairbanks, AK 99775 IETC No. 9701 March 31, 1997 Reprinted October 2003 Table of Contents List of Figures .............................................................................................................. iii List of Tables ................................................................................................................. v Acknowledgments...................................................................................................... viii List of Acronyms .......................................................................................................... ix Risk Terminology .......................................................................................................... x Executive Summary ..................................................................................................... xi 1.0 Introduction ......................................................................................................... 1-1 1.1 Basics of Risk Assessment ..................................................................................1-3 1.2 Approach—Ecological Risk Assessment Applied Regionally ...............................1-5 1.3 Scope of the Port Valdez Assessment ............................................................... 1-11 2.0 Methods ............................................................................................................... 2-1 2.1 Problem Formulation............................................................................................2-1 2.2 Analysis ............................................................................................................. 2-11 2.3 Integrated Risk Scenarios .................................................................................. 2-23 2.4 Uncertainty Analysis .......................................................................................... 2-24 3.0 Characteristics of the Marine Environment ...................................................... 3-1 3.1 The Physical Environment ...................................................................................3-1 3.2 The Biological Environment .................................................................................3-3 3.3 The Human Environment ................................................................................... 3-11 3.4 Disturbance in the Environment ......................................................................... 3-14 3.5 Public Concerns ................................................................................................. 3-17 4.0 Assessment Endpoints ....................................................................................... 4-1 4.1 Water and Sediment Quality ................................................................................4-1 4.2 Commercial, Sport, and Personal Use Fisheries ..................................................4-3 4.3 Wildlife Populations .............................................................................................4-4 5.0 Conceptual Model ............................................................................................... 5-1 5.1 Sub-Area Delineation ...........................................................................................5-2 5.2 Source Identification ............................................................................................5-7 5.3 Habitat Identification .......................................................................................... 5-16 5.4 Impact Identification ........................................................................................... 5-24 5.5 Exposure and Effect Links ................................................................................. 5-28 6.0 Relative Risks in Port Valdez: Results of the Model ....................................... 6-1 6.1 Characteristics of the Model .................................................................................6-1 6.2 Relative Risk by Sub-Area ...................................................................................6-2 6.3 Relative Risk by Source .......................................................................................6-3 6.4 Relative Risk by Habitat .......................................................................................6-3 6.5 Relative Risk within a Sub-Area ...........................................................................6-4 i 7.0 Confirmation of Risk Rankings in Port Valdez ................................................. 7-1 7.1 Comparison to Benchmark Values .......................................................................7-1 7.2 Estimating the Risk of Toxicity .............................................................................7-8 7.3 Bioassay Testing in the Field ............................................................................. 7-10 8.0 Exposure and Effects in Port Valdez ................................................................. 8-1 8.1 Chemicals Dissolved or Suspended in the Water Column ...................................8-2 8.2 Organotins ...........................................................................................................8-3 8.3 Organics in the Sediment .....................................................................................8-5 8.4 Large Oil Spills.....................................................................................................8-6 8.5 Non-native Species ..............................................................................................8-8 8.6 Behavioral and Physical Disturbances .................................................................8-9 8.7 Impacts to Populations ....................................................................................... 8-10 9.0 Follow-up Scenario: An Example of a Multiple Stressor Scenario ................ 9-1 9.1 Risk of Exposure Related to Habitat ....................................................................9-1 9.2 Risk of Effects to Clams in Sediment ...................................................................9-3 9.3 Uncertainty ..........................................................................................................9-4 10.0 Uncertainty Analysis ....................................................................................... 10-1 10.1 Sensitivity Analysis for the Relative Risk Model ................................................. 10-2 10.2 Uncertainty in the Confirmatory Analyses .......................................................... 10-7 11.0 Risk Summary .................................................................................................. 11-1 11.1 Summary of Relative Risk between Sub-Areas of the Port ................................ 11-1 11.2 Port-Wide Risks ................................................................................................. 11-6 11.3 Conclusions ....................................................................................................... 11-6 12.0 References ....................................................................................................... 12-1 APPENDIX A: Ecological Risk Guidance APPENDIX B: Port Valdez Species List APPENDIX C: Sub-Area Characterizations APPENDIX D: Relative Risk Model APPENDIX E: PAH Model ii List of Figures Figure 1-1 Map of Port Valdez study area. .........................................................................1-2 Figure 1-2 Effects threshold. ..............................................................................................1-4 Figure 1-3 Comparison of risk components at a0 the traditional small-scale, and b) the regional large-scale. .........................................................................1-6 Figure 1-4 Combinations possible in a system with two sources, two habitats, and two impacts of concern. .............................................................................1-8 Figure 1-5 Ecological risks resulting from the interaction between sources, habitats, and ecological impacts .......................................................................1-9 Figure 1-6 Integration (through overlap) of the possible combinations of two sources and two habitat types that can influence the risk of an impact to an assessment endpoint ...............................................................................1-9 Figure 1-7 Method of comparing and combining risk components in sub-areas of Port Valdez through (a) ranking, and weights based on likelihood of (b) exposures and (c) effects. .....................................................................