FINAL SITE INSPECTION REPORT COPPER CITY MILL AND GRANITE LAKE PROSPECT WENATCHEE NATIONAL FOREST February 2010 Prepared for: USDA Forest Service Prepared by: 111 SW Columbia, Suite 1500 Portland, Oregon 97201-5850 25696996 TABLE OF CONTENTS SECTION PAGE LIST OF ACRONYMS .............................................................................................................................iii EXECUTIVE SUMMARY ........................................................................................................................ v SITE INSPECTION DATA SUMMARY SHEET.................................................................................vii 1.0 INTRODUCTION AND OBJECTIVES...................................................................................... 1 2.0 SITE DESCRIPTION.................................................................................................................... 1 2.1 Location .............................................................................................................................. 1 2.2 Operational History.............................................................................................................3 2.3 Waste Characteristics.......................................................................................................... 4 2.4 Site Descriptions................................................................................................................. 5 2.4.1 Topography and Climate ....................................................................................... 5 2.4.2 Ecological Setting.................................................................................................. 6 2.4.3 Sensitive Environments.......................................................................................... 8 2.4.4 Threatened, Endangered and Special Status Species ............................................ 9 2.4.5 Population and Land Use .................................................................................... 10 3.0 PATHWAY AND ENVIRONMENTAL HAZARD ASSESSMENT ...................................... 10 3.1 Groundwater Exposure Pathway....................................................................................... 11 3.1.1 Targets ................................................................................................................. 11 3.1.2 Geologic Setting................................................................................................... 11 3.1.3 Hydrogeology....................................................................................................... 12 3.1.4 Groundwater Pathway Summary......................................................................... 13 3.2 Surface Water Exposure Pathway..................................................................................... 13 3.2.1 Targets ................................................................................................................. 13 3.2.2 Aquatic Invertebrate Survey Results.................................................................... 15 3.2.3 Hydrologic Setting ............................................................................................... 16 3.2.4 Analytical Results for Surface Water................................................................... 17 3.2.5 Surface Water Pathway Summary ....................................................................... 18 3.2.6 Sediment Exposure Pathway................................................................................ 19 3.2.6.1 Targets.................................................................................................. 19 3.2.6.2 Analytical Results for Sediment........................................................... 20 3.2.6.3 Sediment Pathway Summary ............................................................... 21 3.3 Soil Exposure Pathway ..................................................................................................... 21 3.3.1 Targets ................................................................................................................. 21 3.3.2 Previous Investigations........................................................................................ 21 3.3.3 Analytical Results for Soil.................................................................................... 22 3.3.4 Soil Pathway Summary ........................................................................................ 25 3.4 Air Exposure Pathway ...................................................................................................... 26 3.4.1 Targets ................................................................................................................. 26 3.4.2 Air Exposure Pathway Summary ......................................................................... 26 4.0 STREAMLINED RISK ASSESSMENT AND EVALUATION.............................................. 26 4.1 Streamlined Human Health Risk Assessment................................................................... 26 4.1.1 Risk and Hazard Estimates.................................................................................. 27 4.1.2 Determination of Hotspots................................................................................... 27 4.1.3 Determination of Clean-up Level ........................................................................ 28 4.1.4 Summary .............................................................................................................. 29 4.2 Streamlined Ecological Risk Assessment and Evaluation................................................ 29 i TABLE OF CONTENTS SECTION PAGE 4.2.1 Conceptual Ecological Exposure Model ............................................................. 30 4.2.2 Risk and Hazard Estimates.................................................................................. 30 4.2.3 Determination of Clean-up Level ........................................................................ 31 4.2.4 Summary .............................................................................................................. 32 4.3 Streamlined Risk Assessment Conclusions and Recommendation .................................. 32 5.0 CONCLUSIONS AND RECOMMENDATIONS..................................................................... 33 5.1 Conclusions....................................................................................................................... 33 5.2 Recommendations............................................................................................................. 34 6.0 FOREST SERVICE DISCLAIMER.......................................................................................... 34 7.0 REFERENCES............................................................................................................................. 35 TABLES Table 1 Surface Water Data Summary and Screening – Copper City Mill Table 2 Arsenic and Chromium Speciation Results Table 3 Surface Water Data Summary and Screening – Granite Lake Prospect Table 4 Sediment Data Summary and Screening – Copper City Mill Table 5 Waste Rock / Soil and Sediment Data and Screening – Granite Lake Prospect Table 6 Waste Rock / Soil Data and Screening – Copper City Mill Table 7 Background Soil Data Table 8 Waste Rock, Soil and Sediment Grain Size Data Table 9 Waste Rock ABA Data Table 10 TCLP and SPLP Results FIGURES Figure 1 Project Vicinity Map Figure 2 Vicinity Map Figure 3 Elevation Contours - Copper City Mill Figure 4 Elevation Contours - Granite Lake Prospect Figure 5 Wetlands - Copper City Mill Figure 6 Wetlands - Granite Lake Prospect Figure 7 Conceptual Site Model - Copper City Mill Figure 8 Conceptual Site Model - Granite Lake Prospect Figure 9 Sample Locations - Copper City Mill Figure 10 Sample Locations - Granite Lake Prospect Figure 11 Well Locations Figure 12 Surface Water Rights APPENDICES Appendix A Photographic Log Appendix B Waste Rock Volume Calculations and Cross Sections Appendix C Streamlined Human Health and Ecological Risk Assessment Appendix D Invertebrate Analysis Report Appendix E Analytical Laboratory Reports & QC Report ii ACRONYMS AND ABBREVIATIONS ABA acid-base accounting AGP acid generating potential AMD acid mine drainage amsl above mean sea level ANP acid neutralization potential APA abbreviated preliminary assessment bcy bank cubic yards BLM Bureau of Land Management CERCLA Comprehensive Environmental Response Compensation Liability Act CERCLIS Comprehensive Environmental Response Compensation and Liability Information System CHU critical habitat unit COC chemical of concern COI chemical of interest COPC chemical of potential concern CPEC chemical of potential ecological concern CSM conceptual site model CTE central tendency exposure DEQ Department of Environmental Quality Ecology Washington Department of Ecology EE/CA engineering evaluation/cost analysis EPC exposure point concentration GPS global positioning system HHRA human health risk assessment MCL maximum contaminant level MDC maximum detected concentration MDL method detection limit MTCA Model Toxics Control Act NFS National Forest System NNP net neutralization potential NPR neutralization potential ratio OECA/FFEO Office of Enforcement and Compliance Assurance / Federal Facilities Enforcement Office PAG potentially acid generating PEMC palustrine, emergent, seasonally flooded PEMF palustrine, emergent, semipermanentaly flooded PEMG palustrine, emergent, intermittently exposed PFOA palustrine,