Engineering & Environmental Services

1 1682 Novato Boulevard Suite 100 Novato, California 94947-7021 Tel (415) 899-1600 Fax (415) 899-1601 PES Environmental , & Environmental Services A Report Prepared For: California Regional Water Quality Control Board San Francisco Bay Region 1515 Clay Street, Suite 1400 Oakland, California 94612 Attention: Mr. Alec W. Naugle, SUMMARY OF REMEDIAL INVESTIGATIONS, FEASIBILITY STUDY AND REMEDIAL ACTION PLAN NAPA PIPE FACILITY 1025 kaiser ROAD NAPA, CALIFORNIA _____ VOLUME 4 SITE 6 FORMER MACHINE SHOP, FORMER DRUM STORAGE AREA, AND SOUTHEASTERN PORTION OF FABRICATION BUILDINGS _____ JUNE 8, 2007 By: D R A F T _____ Gary Thomas Senior Geologist, D R A F T _____ Robert S.

2 Creps, Principal Engineer D R A F T _____ Carl J. Michelsen, , Principal Geochemist PES Environmental , Inc. ii D R A F T TABLE OF CONTENTS LIST OF TABLES .. vii LIST OF ILLUSTRATIONS ..ix INTRODUCTION ..1 Regulatory Context and Cleanup Level Selection ..2 Objectives of RI/FS/RAP ..4 SITE BACKGROUND ..5 Site Site Geology and Hydrogeology ..8 Facility-Wide 8 Younger Alluvium .. 8 Older Alluvium .. 8 Bedrock 8 Site-Specific Hydrogeology ..8 Fill Unit .. 9 Silt/Clay 10 Partially Cemented Silt/Sand 10 Site 6 Groundwater Occurrence and Flow Directions .. 11 Shallow Groundwater Zone.

3 11 Deep Groundwater Zone .. 13 Aquifer 14 Tidal Influence .. 14 Previous 15 Soil and Groundwater Testing at the kaiser Steel Corporation Pipe Mill and Fabrication Facility in Napa California (1987) ..16 Site Investigation Report for the Napa Pipe Corporation Facility (1990) .. 17 June and July 1990 18 Site 6 Characterization and Remedial Action Plan (May 1996).. 19 Phase II Site Investigation by Shaw Environmental 20 Facility-Wide Groundwater Monitoring 20 Summary of Interim Groundwater Remedial 22 SUPPLEMENTAL REMEDIAL INVESTIGATION .. 23 Field Activities and 23 Pre-Field Activities .. 25 Sampling Methods.

4 25 Analytical Methods ..26 Analytical Results .. 26 PES Environmental , Inc. iii D R A F T TABLE OF CONTENTS (Continued) Soil Results .. 26 Petroleum 26 Volatile Organic 27 Groundwater Results .. 28 Petroleum 28 Volatile Organic 29 NATURE AND EXTENT OF CONTAMINATION .. 29 Nature and Extent of Contamination in 29 Petroleum 30 TPH as Motor Oil .. 30 TPH as Diesel .. 31 Volatile Organic 31 Nature and Extent of Contamination in Groundwater .. 32 Petroleum 32 Separate-Phase 32 Dissolved-Phase Petroleum Hydrocarbons ..32 Volatile Organic 34 Conceptual Site Model .. 34 CONTAMINANT FATE AND 35 CHEMICALS OF CONCERN AND REMEDIATION 36 Chemicals of Concern.

5 36 Soil .. 37 37 Summary of Chemicals of Concern .. 38 Cleanup Levels for Chemicals of Concern .. 39 Areas Requiring Remediation .. 39 Areas and Volumes of Soil Exceeding Cleanup Levels .. 39 Areas and Volumes of Groundwater Exceeding Cleanup 41 FEASIBILITY STUDY SCOPING .. 41 Scope of the Feasibility 41 Applicable or Relevant and Appropriate Requirements and To Be Considered Factors for Impacted Soil and 42 Potential Chemical-Specific ARARs and TBCs .. 43 Potential Location-Specific ARARs and TBCs .. 43 Potential Action-Specific ARARs and 43 Additional Factors for Remedial Action Objective 44 Remedial Action Objectives.

6 45 RAOs for Soil .. 45 RAOs for Groundwater .. 45 PES Environmental , Inc. iv D R A F T TABLE OF CONTENTS (Continued) General Response 46 IDENTIFICATION AND SCREENING OF REMEDIAL TECHNOLOGIES .. 46 Preliminary Technology Identification and Screening .. 47 Technology Identification .. 47 Technology Screening .. 47 Soil Treatment Technologies .. 48 Excavation .. 48 Ex Situ Low Temperature Thermal Desorption .. 49 50 Landfarming .. 51 In Situ Chemical Oxidation .. 51 Off-Site 52 Groundwater Treatment 52 In Situ Enhanced Bioremediation .. 53 In Situ Chemical Oxidation .. 53 Saturated Soil Excavation.

7 54 Existing Wastewater Treatment 55 Summary of Retained Remedial Technologies .. 55 DEVELOPMENT OF REMEDIAL ALTERNATIVES .. 56 Approach to Developing Remedial Alternatives .. 57 General Remediation 57 In Situ Tool Box .. 58 Ex Situ Tool Box and Soil Management Protocol .. 59 Alternative 1 No Action .. 60 Alternative Description .. 60 Cost .. 60 Alternative 2 Maintain Existing Remedial Actions .. 61 Alternative Description .. 61 Cost .. 61 Alternative 3 Ex Situ Source Area Soil and Groundwater Treatment and In situ Groundwater Plume Remediation .. 61 Alternative 3 Description .. 61 Cost .. 64 Alternative 4 Ex Situ Soil and Groundwater Remediation.

8 64 Alternative Description .. 64 Cost .. 66 EVALUATION OF REMEDIAL 66 Criteria for Evaluation .. 66 Threshold 66 Balancing Criteria .. 67 PES Environmental , Inc. v D R A F T TABLE OF CONTENTS (Continued) Modifying Criteria .. 67 Detailed Evaluation of Alternatives .. 68 Alternative 1 No Action .. 68 Alternative 2 Maintain Existing Remedial Actions .. 68 Alternative 3 Ex Situ Source Area Soil and Groundwater Treatment and In Situ Groundwater Remediation .. 68 Alternative 4 Ex Situ Soil and Groundwater Remediation .. 69 Summary of Comparison of Remedial Alternatives .. 69 Recommended Remedial Alternative.

9 69 REMEDIAL ACTION PLAN IMPLEMENTATION .. 69 Conceptual Remedial Design .. 70 Remediation Procedures and the Soil Management Protocol .. 70 Permitting and Contractor Health and Safety .. 71 Site Preparation .. 71 Verification Sampling .. 72 Dust and Odor Control .. 72 72 Excavation 73 Schedule of Remedial Action Implementation and 73 Performance Criteria .. 73 73 74 TABLES ILLUSTRATIONS APPENDICES A Former Machine Shop Floor Plan B Supplemental Remedial Investigation Lithologic Logs C Geologic Cross Sections Prepared by Montgomery Watson D Previous Investigation Lithologic Logs and Monitoring Well Completion Diagrams E Tables and Plates for 1987 Soil and Groundwater Testing by James M.

10 Montgomery Consulting Engineers, Inc. F Tables and Plates for 1989 Soil and Groundwater Investigation by James M. Montgomery Consulting Engineers, Inc. PES Environmental , Inc. vi D R A F T TABLE OF CONTENTS (Continued) G Tables and Plates for 1990 Soil Investigation by James M. Montgomery Consulting Engineers, Inc. H Tables and Plates from the 1996 Site 6 Characterization and Remedial Action Plan by Montgomery Watson I Tables and Plates from the December 2005 Phase II Site Investigation by Shaw Environmental Inc. J Laboratory Analytical Reports and Chain of Custody Forms K Chemical Fate and Transport From Montgomery Watson s 1996 Site 6 Characterization and Remedial Action Plan DISTRIBUTION PES Environmental , Inc.