Remedial Investigation/Feasibility Study Report for Lower Watts Bar Reservoir Operable Unit Jacobs Engineering Group, Inc
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DOE/OR/01-1282&D4 Remedial Investigation/Feasibility Study Report for Lower Watts Bar Reservoir Operable Unit Jacobs Engineering Group, Inc. contributed to the preparation of this document and should not be considered an eligible contractor for its review. DOE/OR/01-1282&D4 ORNL/ER-244&D4 Energy Systems Environmental Restoration Program Clinch River Environmental Restoration Program Remedial Investigation/Feasibility Study Report for Lower Watts Bar Reservoir Operable Unit IIv>S o "8 s& llifBO * H il: li-siJ3 - s «- S3 CO 0} ~ Q. a a to •> o o c ! as-— o •If .1 Date Issued—March 1995 «> « K n « .? .5 Jg i-J •3 g C w CU u "8 a s w g fj 2 o. 8f .* c >?o o SI I I 'S » •so 5. •» & S 5 • « 'I Prepared by I* Environmental Sciences Division I | 8 I! Oak Ridge National Laboratory ! and Jacobs Engineering Group, Inc. •a § ii o g IS 1P O 0 Prepared for U.S. Department of Energy Office of Environmental Management SI II P. « Ht l under budget and reporting code EW 20 Environmental Restoration and Waste Management Programs Oak Ridge National Laboratory Oak Ridge, Tennessee 37831-6285 managed by MARTIN MARIETTA ENERGY SYSTEMS, INC. for the U.S. DEPARTMENT OF ENERGY under contract DE-AC05-84OR21400 DISTRIBUTION OF THIS DOCUMENT IS UNUMnTHJ PLC DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. CONTENTS FIGURES vii TABLES ix ABBREVIATIONS xiii PREFACE xv EXECUTIVE SUMMARY xvii 1. INTRODUCTION 1-1 1.1 REGULATORY INITIATIVE 1-1 1.2 OAK RIDGE RESERVATION ENVIRONMENTAL RESTORATION PROGRAM 1-1 1.3 CLINCH RIVER ENVIRONMENTAL RESTORATION PROGRAM 1-2 1.4 OBJECTIVES AND SCOPE OF THIS REPORT 1-2 1.5 SCHEDULE 1-3 2. CHARACTERIZATION OF ENVIRONMENTAL SETTING 2-1 2.1 GEOGRAPHY 2-1 2.2 DEMOGRAPHY 2-1 2.3 CLIMATE 2-6 2.4 TOPOGRAPHY, GEOLOGY, AND SOILS 2-8 2.4.1 Topography 2-8 2.4.2 Geology 2-8 2.4.3 Soils 2-11 2.4.4 Groundwater 2-11 2.5 SURFACE WATER 2-13 2.5.1 Physical Characteristics 2-13 2.5.2 Water Quality 2-19 2.6 SEDIMENT 2-20 2.7 ECOLOGY 2-22 2.7.1 Aquatic Resources 2-25 2.7.2 Terrestrial Resources 2-27 3. SITE HISTORY AND CURRENT CONDITIONS 3-1 3.1 RELEASE HISTORY 3-1 3.1.1 Releases from the Y-12 Plant 3-1 3.1.2 Releases from the K-25 Site 3-6 3.1.3 Releases from Oak Ridge National Laboratory 3-9 3.1.4 Summary of Significant Releases 3-14 iii 3.2 SUMMARY OF EXISTING DATA 3-14 3.2.1 Annual Surveys of Gamma Activity in Clinch and Tennessee River Bottom Sediments 3-14 3.2.2 Clinch River Study 3-15 3.2.3 1977 Clinch River Sediment Survey 3-24 3.2.4 Metals and PCBs in TVA Reservoir Sediments 3-25 3.2.5 Environmental Fate of Mercury and 137Cs Discharged from ORR Facilities 3-27 3.2.6 TVA Instream Contaminant Study 3-29 3.2.7 Oak Ridge Gaseous Diffusion Plant Sediment Survey 3-35 3.2.8 Transport and Accumulation of 137Cs and Mercury in the Clinch River and Watts Bar Reservoir System 3-38 3.2.9 TVA Recreation Area and Water Intake Sampling 3-40 3.2.10 TVA Fish Tissue Studies 3-45 3.2.11 TVA Annual Radiological Environmental Monitoring, Watts Bar Nuclear Plant 3-46 3.2.12 TVA Reservoir Monitoring Program—Sediment 3-50 3.2.13 ORR Environmental Monitoring Data 3-50 3.2.14 Arsenic Biogeochemistry in the Clinch River and Watts Bar Reservoir 3-53 3.2.15 TWRA Non-point Source Pesticide Study 3-54 3.2.16 CRRI Phase 1 Investigation 3-55 3.3 SUMMARY OF SITE CHARACTERIZATION 3-70 4. APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS 4-1 4.1 CHEMICAL-SPECIFIC ARARs 4-1 4.1.1 Surface Water 4-2 4.1.2 Sediment 4-2 4.2 RADIATION PROTECTION STANDARDS 4-4 4.3 LOCATION-SPECIFIC ARARs 4-5 4.3.1 Wetlands and Floodplains 4-5 4.3.2 Aquatic Resources 4-5 4.3.3 Endangered and Threatened Species 4-5 4.3.4 Archaeological and Historical Resources 4-9 4.4 ACTION-SPECIFIC ARARs 4-9 4.4.1 The No Action Response 4-9 4.4.2 Use of Institutional Controls and Advisories 4-9 4.4.3 Removal, Treatment, and Containment Response Actions 4-10 5. HUMAN HEALTH RISK ASSESSMENT 5-1 5.1 DATA EVALUATION 5-1 5.1.1 Data Compilation 5-3 5.1.2 Water Data 5-6 5.1.3 Sediment Data 5-7 5.1.4 Fish Data 5-8 5.2 EXPOSURE ASSESSMENT 5-9 5.2.1 Characterization of Exposure Setting 5-9 5.2.2 Identification of Exposure Scenarios 5-11 5.2.3 Quantification of Exposure 5-13 iv 5.3 TOXICITY ASSESSMENT 5-21 5.3.1 Contaminant-Specific Toxicity Assessment 5-21 5.3.2 Chemicals Without EPA Toxicity Values 5-33 5.4 RISK CHARACTERIZATION 5-37 5.4.1 Risk Characterization Approach for Carcinogens 5-38 5.4.2 Risk Characterization Approach for Noncarcinogens 5-39 5.4.3 Risk Characterization Results for Current Conditions 5-39 5.4.4 Risk Characterization Results for Future Conditions 5-42 5.4.5 Special Case—Lead 5-45 5.4.6 Risk Characterization Summary 5-45 5.5 QUANTITATIVE UNCERTAINTY ANALYSIS 5-51 5.5.1 Uncertainty Analysis for the Fish Consumption Scenario 5-51 5.5.2 Uncertainty Analysis for Exposure to " 'Cs via the Dredging Scenario . 5-58 5.6 SUMMARIES AND CONCLUSIONS 5-60 5.5.1 Chemicals of Potential Concern 5-60 5.5.2 Exposure Assessment 5-60 6. ECOLOGICAL RISK ASSESSMENT REPORT 6-1 6.1 ECOLOGICAL HAZARD IDENTIFICATION 6-1 6.1.1 Ecological Endpoints 6-1 6.1.2 Environmental Description 6-6 6.1.3 Sources 6-6 6.1.4 Conceptual Models 6-7 6.2 EXPOSURE ASSESSMENT 6-7 6.2.1 Aqueous Exposures 6-7 6.2.2 Sediment Exposures 6-10 6.2.3 Wildlife Exposures to Contaminated Fish 6-11 6.2.4 Soil Exposures 6-11 6.3 EFFECTS ASSESSMENT 6-12 6.3.1 Conventional Toxicity Data 6-12 6.3.2 Media Toxicity Data 6-16 6.3.3 Biological Survey Data 6-16 6.4 RISK CHARACTERIZATION 6-20 6.4.1 Risk Integration for Current Conditions 6-20 6.4.2 Risk Integration for Future Conditions 6-28 6.4.3 Uncertainties 6-30 6.4.4 Comparison to Human Health Risks 6-33 6.5 SUMMARY AND CONCLUSIONS 6-34 7. SCREENING OF RESPONSE ACTIONS 7-1 7.1 GENERAL RESPONSE ACTIONS 7-1 7.1.1 Monitoring 7-1 7.1.2 Institutional Controls and Advisories 7-1 7.1.3 Source Containment 7-2 7.1.4 Source Removal 7-2 7.1.5 In Situ and Ex Situ Treatment 7-2 7.1.6 No Action 7-3 v 7.2 SCREENING OF RESPONSE ACTIONS 7-3 7.2.1 Monitoring 7-3 7.2.2 Institutional Controls and Advisories 7-3 7.2.3 Source Containment 7-3 7.2.4 Source Removal 7-4 7.2.5 In Situ and Ex Situ Treatment 7-4 7.2.6 No Action 7-4 7.3 CONCLUSION 7-4 8. REFERENCES 8-1 Appendix A: DATA, EXPOSURE EQUATIONS, EXPOSURE PARAMETERS, AND TOXICITY VALUES USED IN THE BASELINE HUMAN HEALTH RISK ASSESSMENT A-l Appendix B: RESULTS OF THE BASELINE HUMAN HEALTH RISK CHARACTERIZATION B-l Appendix C: FOODCHAIN MODELS AND TRANSFER FACTORS USED IN THE BASELINE HUMAN HEALTH RISK CHARACTERIZATION C-l Appendix D: METHODOLOGY FOR UNCERTAINTY ANALYSES OF SELECT EXPOSURE PATHWAYS IN THE HUMAN HEALTH BASELINE RISK ASSESSMENT D-l Appendix E: DATA TABLES FOR ECOLOGICAL RISK ASSESSMENT E-l vi FIGURES 2.1 Location of Watts Bar Reservoir 2-2 2.2 Watts Bar Reservoir, indicating the lower Watts Bar CERCLA Operable Unit and its relation to DOE's ORR 2-3 2.3 TVA Reservoir System (TVA 1990) 2-4 2.4 Oak Ridge Reservation 2-5 2.5 Population density within a 50-mile radius of Watts Bar Reservoir 2-7 2.6 Regional physiographic map of eastern Tennessee showing the location of Oak Ridge in the Valley and Ridge Province 2-9 .2.7 Geologic map of eastern Tennessee 2-10 2.8 Schematic vertical relationships of flow zones of the ORR, estimated thickness, water flux, and water types 2-14 2.9 Hipsograph of lower Watts Bar Reservoir 2-15 2.10 Drainage area of the Tennessee River at Watts Bar Dam 2-16 2.11 Seasonal water level elevations in Watts Bar Reservoir 2-18 2.12 Map of the surface sedimentary characteristics based on the visual textural analysis of more than 190 surface sediment samples collected in Watts Bar Reservoir 2-21 2.13 Simplified general ecosystem diagram for LWBR 2-23 3.1 The Y-12 Plant (depicting upper East Fork Poplar Creek environmental restoration operable units 3-2 3.2 The Y-12 Site, including Bear Creek (BC) and Chestnut Ridge (CR) environmental restoration operable units 3-4 3.3 Mercury release history from the Y-12 Plant and 137Cs release history from White Oak Lake (ORNL) 3-5 3.4 The K-25 Site (depicting environmental restoration operable units) 3-7 3.5 ORNL Site (depicting environmental restoration waste area groupings) 3-10 3.6 Gamma count at the surface of sediment from the Clinch and Tennessee rivers in Watts Bar Reservoir 3-16 3.7 Activity profile vs bottom contour in selected areas of Watts Bar Reservoir 3-17 3.8 Major radionuclides found in silt from the Clinch and Tennessee rivers by years 1954-58 3-18 3.9 Mass balance diagram for ^Sr, Clinch River study 3-20 3.10 Mass balance diagram for 137Cs, Clinch River study 3-21 3.11 Section at CRM 7.5 showing penetration, recovery, and gross gamma radioactivity variation with depth for 1962 bottom sediment core samples ...