REPORT ON-PROPERTY SITE INVESTIGATION WORK PLAN Saint-Gobain Performance Plastics Facility 701 Daniel Webster Highway in Merrimack, New Hampshire Submitted to: New Hampshire Department of Environmental Services Hazardous Waste Remediation Bureau 29 Hazen Drive, PO Box 95 Concord, New Hampshire 03302 Submitted by: Saint-Gobain Performance Plastics Corp. 14 McCaffrey Street Hoosick Falls, New York 12090 Submitted by: Golder Associates Inc. 670 North Commercial Street, Suite 103 Manchester, New Hampshire, USA 03101 June 8, 2018 June 8, 2018 1668623 Table of Contents 1.0 INTRODUCTION ............................................................................................................................................. 1 2.0 BACKGROUND .............................................................................................................................................. 1 2.1 Property and Facility History ................................................................................................................ 1 2.2 Summary of Previous Investigations .................................................................................................... 3 3.0 PRELIMINARY CONCEPTUAL SITE MODEL .............................................................................................. 3 3.1 Geologic and Hydrogeologic Setting .................................................................................................... 4 3.2 Potential Releases and Transport Mechanisms .................................................................................. 5 3.3 Nature and Extent of PFAS .................................................................................................................. 6 4.0 INVESTIGATION OBJECTIVES AND SCOPE OF WORK ............................................................................ 7 4.1 Investigation Objectives ....................................................................................................................... 7 4.2 Scope-of-Work ..................................................................................................................................... 8 4.2.1 PRA-Specific Investigations ............................................................................................................ 9 4.2.2 Soil Sampling and Analysis ........................................................................................................... 14 4.2.3 Groundwater Sampling and Analysis ............................................................................................ 15 4.2.4 Hydraulic Testing and Water Level Elevation Monitoring ............................................................. 15 5.0 METHODS AND PROCEDURES ................................................................................................................. 15 5.1 General ............................................................................................................................................... 15 5.2 Soil Boring Advancement and Soil Sampling ..................................................................................... 16 5.3 Monitoring Well Installation ................................................................................................................ 16 5.3.1 Installation of Monitoring Wells ..................................................................................................... 16 5.3.2 Installation of Temporary Monitoring Wells ................................................................................... 17 5.3.3 Development ................................................................................................................................. 17 5.3.4 Surveying ...................................................................................................................................... 18 5.4 Groundwater Sampling ...................................................................................................................... 18 5.4.1 Sample Purging and Stabilization ................................................................................................. 18 5.4.2 Sample Collection ......................................................................................................................... 19 ii June 8, 2018 1668623 5.5 Groundwater Elevation Measurement ............................................................................................... 20 5.6 Quality Control.................................................................................................................................... 20 5.6.1 Field Duplicates............................................................................................................................. 20 5.6.2 Trip Blanks .................................................................................................................................... 21 5.6.3 Equipment Blanks ......................................................................................................................... 21 5.6.4 Field Blanks ................................................................................................................................... 21 5.6.5 Analytical QA/QC .......................................................................................................................... 21 5.7 Decontamination ................................................................................................................................ 21 5.8 Investigation-Derived Waste .............................................................................................................. 22 5.9 Equipment Calibration ........................................................................................................................ 22 5.10 Slug Testing ....................................................................................................................................... 22 5.11 Data Management .............................................................................................................................. 23 5.12 Data Validation ................................................................................................................................... 24 6.0 SCHEDULE AND PROJECT ORGANIZATION ........................................................................................... 24 6.1 Schedule ............................................................................................................................................ 24 6.2 Project Organization ........................................................................................................................... 25 7.0 ACRONYMNS AND ABBREVIATIONS ....................................................................................................... 26 8.0 REFERENCES CITED .................................................................................................................................. 28 9.0 CLOSING ...................................................................................................................................................... 30 TABLES Table 1 Potential Release Areas Table 2 Soil Investigation Locations – PFAS Analysis Table 3 Soil Investigation Locations – Non-PFAS Analysis Table 4 Overburden Groundwater Investigation Locations – First Sampling Event Table 5 Overburden Groundwater Investigation Locations – Second Sampling Event Table 6 Bedrock Groundwater Investigation Locations Table 7 PFAS Analyte List iii June 8, 2018 1668623 FIGURES Figure 1 Facility Location Map Figure 2 Facility and Nearby Property Locations Figure 3 Facility Plan Figure 4 Potential Release Areas Figure 5 Proposed Investigations APPENDICES Appendix A NHDES SI Work Plan Comments Appendix A-1 NHDES Comment Letter Appendix A-2 Response to NHDES Comments Appendix B Facility Release History Appendix C General Field Methods for PFAS Sampling Programs Appendix D Geoprobe Screen Point 16 Groundwater Sampler Standard Operating Procedure iv June 2018 1668623 1.0 INTRODUCTION On behalf of Saint-Gobain Performance Plastics (SGPP), Golder Associates Inc. (Golder) prepared this On- property Site Investigation Work Plan (Work Plan) for the SGPP Facility located at 701 Daniel Webster Highway in Merrimack, New Hampshire (the Facility; as shown in Figure 1). The New Hampshire Department of Environmental Services (NHDES) has designated the property a Remediation Site (Facility ID #199712055, Project Number 36430) due to the presence of perfluoroalkyl substances (PFAS) in soil and groundwater. This Work Plan presents the objectives, proposed scope-of-work and methods for assessing “on-property” (i.e., Tax Lot 6E-3-2) soil and groundwater to satisfy the Site Investigation requirements outlined in ENV-Or 606. In addition to the scope-of-work described herein, SGPP is performing on-property quarterly groundwater monitoring, off-property investigation of surface water, stormwater and garden soils, and sampling of off-property residential wells under separate work plans. The remainder of this Work Plan is organized as follows: Section 2 – Background Section 3 – Preliminary Conceptual Site Model Section 4 – Investigation Objectives and Scope-of-Work Section 5 – Methods and Procedures Section 6 – Schedule and Project Organization Section 7 – Acronyms and Abbreviations Section 8 – References Cited 2.0 BACKGROUND Following Initial Site Characterization (ISC) field investigation activities, C. T. Male Associates (C.T.