RI/FS Report Taylor Lumber and Treating Superfund Site Feasibility Study Volume IV Prepared for U.S. Environmental Protection Agency WA No. 225-RICO-10F1/RAC V Contract No. 68-W6-0025 July 2004 Revised December 2004 CVO\043650001 CVO\043650001 Contents Section Page 1 Introduction ......................................................................................................................... 1-1 1.1 Purpose of Report...................................................................................................... 1-1 1.2 Report Organization.................................................................................................. 1-1 1.3 Background Information .......................................................................................... 1-1 1.3.1 Site Description ........................................................................................... 1-1 1.3.2 Property History ......................................................................................... 1-2 1.4 Results from the RI Report and Baseline Risk Assessment ................................. 1-4 1.4.1 On-property Surface Soil Outside Barrier Wall...................................... 1-5 1.4.2 Soil Storage Cells ........................................................................................ 1-6 1.4.3 Off-property Ditch Soil .............................................................................. 1-6 1.4.4 Residential Soil............................................................................................ 1-7 1.4.5 River/Creek Sediment............................................................................... 1-7 1.4.6 Contaminated Media Inside Barrier Wall ............................................... 1-8 1.4.7 Groundwater Outside the Barrier Wall................................................... 1-9 1.4.8 Surface Water ............................................................................................ 1-10 1.4.9 Air ............................................................................................................... 1-11 1.5 Summary................................................................................................................... 1-11 2 Remedial Action Objectives ............................................................................................. 2-1 2.1 ARARs......................................................................................................................... 2-1 2.1.1 Chemical-specific ARARs.......................................................................... 2-2 2.1.2 Location-specific ARARs........................................................................... 2-4 2.1.3 Action-specific ARARs............................................................................... 2-5 2.1.4 Summary of Risk–Based Criteria and ARARs........................................ 2-8 2.2 Remedial Action Objectives and Target Areas...................................................... 2-8 2.2.1 Soil Outside the Barrier Wall .................................................................... 2-8 2.2.2 Groundwater Outside the Barrier Wall................................................. 2-11 2.2.3 Contaminated Media Inside the Barrier Wall....................................... 2-12 2.3 General Response Actions...................................................................................... 2-12 3 Identification and Screening of Technologies .............................................................. 3-1 3.1 Presumptive Remedies ............................................................................................. 3-1 3.2 Screening Process....................................................................................................... 3-2 3.3 Soil Outside the Barrier Wall ................................................................................... 3-2 3.3.1 Institutional Controls ................................................................................. 3-2 3.3.2 Containment................................................................................................ 3-3 3.3.3 Removal ....................................................................................................... 3-4 3.3.4 Treatment..................................................................................................... 3-4 3.3.5 Disposal........................................................................................................ 3-7 3.4 Groundwater Outside the Barrier Wall.................................................................. 3-7 3.4.1 Institutional Controls ................................................................................. 3-7 CVO\043650001 III CONTENTS, CONTINUED Section Page 3.4.2 Containment / Removal ............................................................................3-8 3.4.3 Treatment .....................................................................................................3-8 3.5 Contaminated Media Inside the Barrier Wall ......................................................3-10 3.5.1 Institutional Controls................................................................................3-10 3.5.2 Containment ..............................................................................................3-11 3.5.3 Removal......................................................................................................3-12 3.5.4 Treatment ...................................................................................................3-15 3.5.5 Disposal ......................................................................................................3-17 3.6 Summary of Retained Technologies......................................................................3-17 4 Assembly of Remedial Alternatives ................................................................................4-1 4.1 Soil Outside the Barrier Wall (SO) ...........................................................................4-1 4.2 Groundwater Outside the Barrier Wall (GW)........................................................4-2 4.3 Contaminated Media Inside the Barrier Wall (BW) ..............................................4-2 5 Detailed Analysis of Alternatives ....................................................................................5-1 5.1 Evaluation Criteria.....................................................................................................5-1 5.1.1 Overall Protection of Human Health and the Environment.................5-1 5.1.2 Compliance with ARARs...........................................................................5-2 5.1.3 Long-Term Effectiveness and Permanence .............................................5-2 5.1.4 Reduction of Toxicity, Mobility, and Volume through Treatment ......5-2 5.1.5 Short-Term Effectiveness ...........................................................................5-2 5.1.6 Implementability.........................................................................................5-2 5.1.7 Cost................................................................................................................5-3 5.2 Evaluation of Alternatives ........................................................................................5-3 5.2.1 Soil Outside the Barrier Wall (SO) ............................................................5-3 5.2.2 Groundwater Outside the Barrier Wall (GW).........................................5-7 5.2.3 Inside the Barrier Wall (BW)......................................................................5-9 5.2.4 Summary ....................................................................................................5-12 6 References .............................................................................................................................6-1 Appendixes A Probabilistic Risk Assessment B West Facility Soil and Off-property Ditch Hot Spot and Non-Hot Spot Exceedance Maps C Cost Estimates D MW-24s Installation and August 2004 Groundwater Sampling E Residential Soil Removal Action IV CVO\043650001 CONTENTS, CONTINUED Section Page Tables 1-1 Soil Risk Summary 2-1 Summary of Chemical-Specific ARARs 2-2 Risk-based Soil COC Action Levels and Remediation Goals 2-3 Quantity Estimates for Each Cleanup Unit 3-1 Screening of Remediation Technologies 3-2 Summary of Retained Technologies 4-1 Screening of Treatment Options for Soil Target Areas 4-2 Alternatives for Soil Outside the Barrier Wall (SO) 5-1 Evaluation of Alternatives for Soil Outside of the Barrier Wall (SO) 5-2 Evaluation of Alternatives for Groundwater Outside of the Barrier Wall (GW) 5-3 Evaluation of Alternatives for All Media inside of the Barrier Wall (BW) Figures 1-1 Facility 2-1 Soil Target Areas Outside the Barrier Wall 2-2 Approximate Area of Residential Remediation 2-3 Pentachlorophenol Concentrations (µg/L) Aug/Sept 2002 CVO\043650001 V Acronyms and Abbreviations AC asphalt concrete ACZA ammoniacal copper zinc arsenate AOC area of contamination ARAR Applicable or relevant and appropriate requirement CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations COC contaminant of concern COPC contaminant of potential concern CWA Clean Water Act DNAPL dense nonaqueous phase liquid DOT Department of Transportation DUS dynamic underground stripping Eco Ecological E&E Ecology and Environment, Inc. EF East Facility ELCR excess lifetime cancer risk EPA United States