SECTION 6 – ECOLOGICAL RISK 6 – ECOLOGICAL RISK ASSESSMENT ... 9285.7-081 Vol. 1, No. 1, ... (Approach for Offshore Ecological Risk Assessment at Maine

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  • Maine Yankee August 2004 Bailey Point RFI Report 6-1

    SECTION 6 ECOLOGICAL RISK ASSESSMENT

    6.1 Introduction.......................................................................................................... 6-3 6.2 Preliminary Problem Formulation ....................................................................... 6-4 6.2.1 Ecological Site Model.......................................................................... 6-5

    6.2.2 Exposure Pathways and Potential Receptors ....................................... 6-6 6.2.3 Assessment and Measurement Endpoints ............................................ 6-9 6.2.4 Summary of Available Data............................................................... 6-11

    6.3 Screening Phase of the Ecological Risk Assessment......................................... 6-12 6.3.1 Sediment Benchmarks........................................................................ 6-12 6.3.2 Sediment Benchmark Screening ........................................................ 6-13 6.3.3 Relationship to Reference Area ......................................................... 6-13 6.3.4 Identification of Preliminary Chemicals of Potential Concern.......... 6-13 6.3.5 Sediment Investigation at the Transmission Line (Silt Spreading) .......... Area .................................................................................................... 6-14 6.3.6 Biota Tissue COPC Concentrations Relative to Reference and Screening

    Values................................................................................................. 6-15 6.3.7 Baseline Ecological Risk Assessment Data Collection Activities..... 6-19

    6.4 Baseline Problem Formulation .......................................................................... 6-19 6.4.1 Toxicity Evaluation............................................................................ 6-19 6.4.2 Refined Ecological Site Model .......................................................... 6-20

    6.5 Ecological Exposure and Effects Assessment ................................................... 6-21 6.5.1 Comparison of COPC Concentrations with Sediment Benchmarks .. 6-21 6.5.2 Evaluation of Chemical Residues in Tissue of Target Receptors ...... 6-22 6.5.3 Exposure Estimation for Upper Trophic Level Receptors................. 6-23 6.5.4 Effects Assessment for Upper Trophic Leve l Receptors................... 6-24 6.5.5 Risk to Upper Trophic Level Receptors ............................................ 6-25 6.5.6 Toxicity of Site Sediment Versus Reference Sediment ..................... 6-27 6.5.7 Benthic Community Structure ........................................................... 6-29

    6.6 Risk Characterization......................................................................................... 6-32 6.6.1 Ecological Risk at Each Outfall Based on the Weight of Evidence .. 6-32 6.6.2 Benthic Community........................................................................... 6-33 6.6.3 Fish..................................................................................................... 6-35 6.6.4 Aquatic Birds ..................................................................................... 6-36 6.6.5 Uncertainty......................................................................................... 6-37

    6.7 Conclusions ........................................................................................................ 6-39

    LIST OF TABLES 6-1 Sediment Screening Values 6-2 Benchmark Quotients at Outfall 005/006 Intertidal Sediments 6-3 Benchmark Quotients at Outfall 005/006 Subtidal Sediments 6-4 Benchmark Quotients at Outfall 008 Subtidal Sediments 6-5 Benchmark Quotients at Outfall 009 Subtidal Sediments 6-6 Benchmark Quotients at Outfall 010 Intertidal Sediments

  • Maine Yankee August 2004 Bailey Point RFI Report 6-2

    6-7 Benchmark Quotients at Outfall 011 Intertidal Sediments 6-8 Benchmark Quotients at Outfall 011 Subtidal Sediments 6-9 Comparison of Metal Concentrations at the Outfalls with the Reference Site 6-10 Summary of Sediment Screening 6-11 Benchmark and Reference Quotients at the Transmission Line (Silt Spreading) Area 6-12 Screening of Maximum Detected Residues in Clam Tissue 6-13 Tissue Concentration Ratios for Clam Tissue 6-14 Screening of Maximum Detected Residues in Mussel Tissue 6-15 Tissue Concentration Ratios for Mussel Tissue 6-16 Screening of Maximum Detected Residues in Mummichog Tissue 6-17 Comparison of Sediment Benchmark Quotients Between First and Second Rounds of

    Sampling 6-18 Risk Ranking for Biota Tissue Concentration Ratios 6-19 Risk Ranking of Biota Tissue Hazard Quotients 6-20 Exposure Parameters for Avian Receptor Species 6-21 Tissue Residue Screening Values for Mummichog 6-22 Tissue Chemical Residue Screening Values for Shortnose Sturgeon 6-23 Ingestion Screening Values for Birds 6-24 Screening of Estimated Chemical Residues in Shortnose Sturgeon Tissue 6-25 Summary of Hazard Quotients for Herring Gull 6-26 Summary of Hazard Quotients for Belted Kingfisher 6-27 Summary of Hazard Quotients for Osprey 6-28 Sediment Toxicity Test Results 6-29 Benthic Community Structure Analysis 6-30 Physical Characteristics of the BCSA Locations 6-31 Species Abundance in Intertidal Samples 6-32 Species Abundance in Subtidal Samples 6-33 Comparison of Sediment PAH Concentrations (ug/kg) with Concentrations Linked to

    Cancer in Fish

    LIST OF FIGURES

    6-1 Ecological Site Model 6-2 Abundance of Streblospio benedicti per sample at the Intertidal Stations 6-3 Abundance of Neanthes virens per sample at the Intertidal Stations 6-4 Abundance of Heteromastus filiformis per sample at the Intertidal Stations 6-5 Abundance of Tharyx acutus per sample at the Intertidal Stations 6-6 Abundance of Tubificidae per sample at the Intertidal Stations 6-7 Abundance of Gemma gemma per sample at the Intertidal Stations 6-8 Abundance of Streblospio benedicti per sample at the Subtidal Stations 6-9 Abundance of Neanthes virens per sample at the Subtidal Stations 6-10 Abundance of Heteromastus filiformis per sample at the Subtidal Stations 6-11 Abundance of Tharyx acutus per sample at the Subtidal Stations 6-12 Abundance of Tubificidae per sample at the Subtidal Stations 6-13 Abundance of Gemma gemma per sample at the Subtidal Stations

  • Maine Yankee August 2004 Bailey Point RFI Report 6-3

    6.1 INTRODUCTION

    This Ecological Risk Assessment (ERA) was prepared to evaluate the potential risk to ecological receptors associated with the marine habitat surrounding the Maine Yankee Atomic Power Station (Maine Yankee). The ERA was prepared as part of the decommissioning of Maine Yankee, specifically as part of the Resource Conservation and Recovery Act (RCRA) process associated with closure of the site-related stormwater outfalls. In addition to assessing the potential baseline ecological risk, the ERA was prepared to develop sufficient information to make informed risk management decisions on an outfall-specific basis.

    The framework and approach for the ERA follows the general guidelines outlined in the United States Environmental Protection Agencys (USEPA) Guidelines for Ecological Risk Assessment, EPA/630/R-95/002F, dated April 1998. In addition, the following documents, which provide risk assessment guidance and/or technical information, were used in the development of the ERA:

    Risk Assessment Guidance for Superfund:Process for Designing and Conducting Ecological Risk Assessments, EPA/540/R-97/006;

    Supplemental Risk Assessment Guidance for the Superfund Program, USEPA, OSWER 9285.7-081 Vol. 1, No. 1, May 1992;

    Intermittent ECO Update Bulletins of USEPA; and

    USEPA Region 1 Risk Updates.

    The ERA discusses the potential for environmental impacts from site-related chemicals in the event that no remedial action is taken. Specifically, the ERA discusses the potential for existing site-related chemicals to impact near-shore intertidal and subtidal habitats of the Back River and Bailey Cove in the vicinity of outfalls 005, 006, 008, 009, 010, 011, and 012. The outfalls are related to areas of the site drained by storm drain systems, as listed in Table 3-1. Potential risks to the environment are assessed for each outfall individually, with the exception of outfalls 005 and 006, which were evaluated together due to their close proximity. The ERA only assesses potential risks to the marine environment since the outfalls discharge to these habitats. Terrestrial or freshwater wetland risks that may be associated with other potential sources on the site were not evaluated in the ERA.

    In addition to the outfalls described above, another area of potential concern was identified by Maine DEP midway through the ERA process. The additional area was the silt spreading area west of the 345 kV Transmission Line. This area is an intertidal mudflat surrounded by a salt marsh and is also evaluated in the ERA.

    A work plan for the ERA (Approach for Offshore Ecological Risk Assessment at Maine Yankee) was included as Appendix E of the Quality Assurance Project Plans (QAPP) for the Maine Yankee Decommissioning Project, RCRA Facility Investigation. During development of the work plan and discussions with regulators, it was determined that the ERA would be limited to the stormwater outfall areas, since no other exposure pathways were identified.

  • Maine Yankee August 2004 Bailey Point RFI Report 6-4

    The work plan was generally followed, but close discussion, consultation, and coordination with the state and federal ecological risk assessors on this project occurred throughout the ERA process. As a result, some modifications to the approach were made in coordination with the state and federal risk assessors.

    The fundamental cha

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