INDOOR AIR QUALITY REPORT #12. Former Raritan Arsenal

Transcription

1 INDOOR AIR QUALITY REPORT #12 FUDS Project Number C02NJ September 2016 Prepared for: U.S. Army Corps of Engineers New England District Contract No. W912DR-13-D-0014 Delivery Order DB03 Prepared by: Avatar Environmental, LLC A Service-Disabled Veteran Owned Small Business

2 Table of Contents SECTION TITLE PAGE 1. INTRODUCTION AND OBJECTIVES Regulatory Requirements and Agency Coordination Background Previous Reporting Groundwater AOCs Requiring No Further Action for Vapor Intrusion IAQ Report #7 Recommendations IAQ Report #8 Recommendations IAQ Report #9 Recommendations IAQ Report #10 Recommendations IAQ Report #11 Recommendations Current IAQ Report Vapor Migration Pathway USACE Indoor Air Evaluation Process METHODOLOGY Sampling Design Sampling Methods Groundwater Evaluation Subslab Soil Gas Sampling Method Building Survey Method Indoor Air Sampling Method Vapor Recovery Air Sampling Method Ambient Air Sampling Method Meteorological Data Quality Assurance/Control Sample Handling and Shipping Data Validation Procedures Available Screening Levels NJDEP Vapor Intrusion Screening Levels Site-Specific Screening Levels Screening Levels Used for Comparisons SAMPLING RESULTS FOR GROUNDWATER AOC Overview of Groundwater AOC Building Survey Subslab Soil Gas and Vapor Recovery System Indoor Air Meteorological Data i

3 Table of Contents, continued SECTION TITLE PAGE Fieldcrest Avenue Prior Investigations Current Investigation Subslab Soil Gas and Vapor Recovery System Results Indoor Air and Background Sampling Results Integrated Discussion of Results Conclusions and Recommendations Campus Plaza Prior Investigations Current Investigation Subslab Soil Gas Results Indoor Air and Background Sampling Results Integrated Discussion of Results Conclusions and Recommendations GROUNDWATER AOC Overview Fernwood Avenue Prior Investigations Current Investigation Conclusions and Recommendations SAMPLING RESULTS FOR GROUNDWATER AOC 8 A/B Overview of Groundwater AOC Building Survey Subslab Soil Gas Indoor Air Meteorological Data EPA Building Prior Investigations Current Investigation Subslab Soil Gas Results Indoor Air and Background Sampling Results Integrated Discussion of Results Conclusions and Recommendations EPA Building Prior Investigations Current Investigation Subslab Soil Gas Sampling Results Indoor Air and Background Sampling Results Integrated Discussion of Results ii

4 Table of Contents, continued SECTION TITLE PAGE Conclusions and Recommendations EPA Building Prior Investigations Current Investigation Subslab Soil Gas Sampling Results Indoor Air and Background Sampling Results Integrated Discussion of Results Conclusions and Recommendations REFERENCES iii

5 Table of Contents, continued List of Appendices Appendix A 160 Fieldcrest Annual Report Appendix B Building 165 Workplan for Vapor Mitigation System and Monitoring Appendix C 102 Fernwood Avenue Annual Report Appendix D EPA Building 10 Optimization Study Appendix E EPA Building 200 Optimization Study Appendix F Site-Specific Screening Criteria Appendix G Leak Test Results Appendix H Indoor Air Building Survey and Sampling Forms Appendix I Meteorological Data Appendix J Laboratory Analytical Results and Data Validation Reports (on CD) Appendix K AOC 2 Historical Results Summary Appendix L Electronic Data Deliverables (on CD) Appendix M Campus Plaza 4 Historic Data Review Appendix N AOC 8 A/B Historical Results Summary List of Tables Table ES-1 Groundwater AOC 2 Sampling Result and Proposed Action Summary Table ES-2 Groundwater AOC 6 Sampling Result and Proposed Action Summary Table ES-3 Groundwater AOC 8 A/B Sampling Result and Proposed Action Summary Table 1-1 Status of Vapor Intrusion Concerns for Groundwater AOCs Table 1-2 List of Tenants and Addresses Table 2-1 Subslab Soil Gas Sample Location Summary Groundwater AOC 2 Table 2-2 Indoor Air Sample Location Summary Groundwater AOC 2 Table 2-3 Subslab Soil Gas Sample Location Summary Groundwater AOC 8 A/B Table 2-4 Indoor Air Sample Location Summary Groundwater AOC 8 A/B Table 2-5 AOC 2: Subslab Soil Gas Sampling Summary Table 2-6 AOC 8 A/B: Subslab Soil Gas Sampling Summary Table 2-7 AOC 2: Indoor Air Sampling Summary Table 2-8 AOC 8 A/B: Indoor Air Sampling Summary Table 2-9 Site-Specific Screening Levels Table 3-1 Contaminants of Potential Concern Groundwater AOC 2 Table 3-2 Subslab Soil Gas Analytical Results: October 2015 and March Fieldcrest: Groundwater AOC 2 Table 3-3 Vapor Recovery Analytical Results: October Fieldcrest: Groundwater AOC 2 Table 3-4 Subslab Soil Gas Analytical Results: March 2016 Campus Plaza 4: Groundwater AOC 2 Table 3-5 Indoor Air Analytical Results: October 2015 and March Fieldcrest: Groundwater AOC 2 iv

6 Table of Contents, continued Table 3-6 Indoor Air Analytical Results: March and May 2016 Campus Plaza 4: Groundwater AOC 2 Table 3-7 Meteorological Data Summary Groundwater AOC 2 Table Fieldcrest Avenue Sample Summary Table 3-9 Campus Plaza 4 Sample Summary Table 4-1 Contaminants of Potential Concern Groundwater AOC 6A Table 5-1 Contaminants of Potential Concern Groundwater AOC 8A/B Table 5-2 Subslab Soil Gas Analytical Results: October 2015 and March 2016 EPA Building 10: Groundwater AOC 8A/B Table 5-3 Subslab Soil Gas Analytical Results: October 2015 and March 2016 EPA Building 200: Groundwater AOC 8A/B Table 5-4 Subslab Soil Gas Analytical Results: October 2015 and March 2016 EPA Building 205: Groundwater AOC 8A/B Table 5-5 Indoor Air Analytical Results: October 2015 and March 2016 EPA Building 10: Groundwater AOC 8A/B Table 5-6 Indoor Air Analytical Results: October 2015 and March 2016 EPA Building 200: Groundwater AOC 8A/B Table 5-7 Indoor Air Analytical Results: October 2015 and March 2016 EPA Building 205: Groundwater AOC 8A/B Table 5-8 Meteorological Data Summary Groundwater AOC 8A/B Table 5-9 EPA Building 10 Sample Summary Table 5-10 EPA Building 200 Sample Summary Table 5-11 EPA Building 205 Sample Summary List of Figures Figure ES-1 Indoor Air Program Overview Figure 1-1 Indoor Air Evaluation Approach Figure 3-1 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, Building 165 Fieldcrest Figure 3-2 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, Campus Plaza 4 Figure 4-1 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, 102 Fernwood Avenue Figure 5-1 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, EPA Building 10 Figure 5-2 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, EPA Building 200 Figure 5-3 PCE & TCE Results for Subslab Soil Gas and Indoor Air Samples, EPA Building 205 Acronyms and Abbreviations v

7 Table of Contents, continued AA AOC Avatar bgs CENAE CENAN CERCLA COPC CP cy DCA DCB DCE DERP DOD EDD EO EWMA EPA FBC FS ft FUDS GWQS GWRAWP IA IAQ LCD MCL MNA MSDS MTBE NAR NCP NJDEP NOAA NPL PCE QA QAPP QC RA RCP RD ambient air area of concern Avatar Environmental, LLC below ground surface U.S. Army Corps of Engineers New England District U.S. Army Corps of Engineers New York District Comprehensive Environmental Response, Compensation, and Liability Act contaminant of potential concern Campus Plaza cubic yard dichloroethane dichlorobenzene dichloroethylene Defense Environmental Restoration Program Department of Defense Electronic Data Deliverable executive order Environmental Waste Management Associates U.S. Environmental Protection Agency Federal Business Center feasibility study feet Formerly Used Defense Site Groundwater Quality Standard Groundwater Remedial Action Work Plan indoor air indoor air quality Local Climatological Data Maximum Contaminant Level monitored natural attenuation material safety data sheet methyl tert-butyl ether Natural Attenuation Report National Contingency Plan New Jersey Department of Environmental Protection National Oceanic and Atmospheric Administration National Priorities List tetrachloroethylene Quality Assurance Quality Assurance Project Plan Quality Control remedial action Raritan Center Parkway remedial design vi

8 Table of Contents, continued RI RPD SARA SOP SSD SSSG SSV SVE TCE UFP USACE USC UST VC VI VIG VR VOC Weston remedial investigation relative percent difference Superfund Amendments and Reauthorization Act standard operating procedure subslab depressurization subslab soil gas subslab venting soil vapor extraction trichloroethylene Uniform Federal Policy U.S. Army Corps of Engineers United States Code underground storage tank vinyl chloride vapor intrusion vapor intrusion guidance vapor recovery volatile organic compound Weston Solutions, Inc. vii

9 Executive Summary This focuses on the results from sampling events completed at the former Raritan Arsenal during October 2015 and March 2016, and supplemental indoor air sampling in May The report summarizes the recent results relative to prior sampling events. The following types of samples were collected: indoor air (IA), subslab soil gas (SSSG), vapor recovery (VR), and ambient air (AA). Buildings requiring ongoing investigation for vapor intrusion (VI) concerns based on prior results from groundwater and VI sampling were sampled for volatile organic compounds (VOCs). Figure ES-1 presents an overview of the VI sampling program at the former Raritan Arsenal. It depicts the various Groundwater Areas of Concern (AOCs) along with the buildings included in the sampling program. The primary site Contaminants of Potential Concern (COPCs) for the Groundwater AOCs have been determined by comparing the most recent groundwater sample results with groundwater screening levels that are protective of the VI pathway. Trichloroethylene (TCE) and vinyl chloride (VC) are the Groundwater AOC 2 COPCs (see Table 3-1). TCE is the COPC for Groundwater AOC 8 A/B (see Table 5-1). The analytical results for all sample types were evaluated collectively to determine whether the VI pathway is complete for each building, to make recommendations for future action(s) and where applicable, to determine if existing subslab depressurization systems (SSDSs) are operating effectively in removing contamination in subslab soil gas. The analytical results were compared with screening levels from the New Jersey Department of Environmental Protection (NJDEP) and site-specific screening levels developed by the U.S. Army Corps of Engineers (USACE). The recommendations for each building are described in the following paragraphs and presented in Tables ES-1 through ES-3. ES-1

10 Groundwater AOC 2 USACE continues to monitor three buildings within Groundwater AOC 2 for potential VI issues: 160 Fieldcrest, 165 Fieldcrest, and Campus Plaza 4. Table ES-1 presents a summary of the recent sampling results along with proposed actions for Groundwater AOC Fieldcrest This building had a passive subslab vapor mitigation system installed in June Subsequent sampling has shown VOC concentrations in VR samples above soil gas screening levels. VOCs have not been observed in the indoor air. The absence of VOCs in indoor air illustrates that the VR system at 160 Fieldcrest is operating as designed. USACE performs an annual inspection of the subslab vapor mitigation system to ensure that the system is operating properly. Appendix A contains the most recent Remedial Action Progress Report (Geosyntec, 2016a) that presents a summary of the activities conducted between 19 November 2014 and 10 November 2015 and the system inspection conducted on 10 November It is recommended that system inspections continue on an annual basis to ensure the VR system continues to operate properly. The next analytical sampling round is scheduled for Fieldcrest The NJDEP installed a SSDS at 165 Fieldcrest in August At that time, lines of evidence for vapor intrusion and building use factors led NJDEP to conclude that the VI pathway was possibly complete. Elevated levels of both TCE and PCE in groundwater in the immediate vicinity of the building at the time of the SSD system install, elevated levels of TCE and PCE in soil gas samples collected beneath the building, levels of PCE in indoor air, and the presence of a child care facility in the building were all factors leading to the decision to install the system. A subset of wells associated with AOC 2 groundwater were most recently sampled in August Results from these samples continue to show an overall decrease in VOC levels in groundwater near 165 Fieldcrest. Per the Work Plan presented in Appendix B, SSDS shutdown testing was conducted in March A focused sampling event was completed one week after SSDS shutdown and a complete sampling event was completed four weeks after SSDS shutdown. ES-2

11 The data from the October 2015 and March 2016 sampling events for 165 Fieldcrest showed that the VI pathway is not complete. The AOC 2 COPCs (TCE and VC) were not detected in any of the IA samples, including the samples that were collected during the March 2016 sampling events when the SSD system was not operating. TCE was detected in one SSSG sample when the SSD system was not operating but the measured concentration was significantly less than the NJDEP soil gas screening level. SSSG Results None of the SSSG sample results for the AOC 2 COPCs were greater than the soil gas screening levels. There was a shutdown (intentional) of the SSD system during the March 2016 sampling. Even during this shutdown, the SSSG results were not a concern for the site COPCs as they were either nondetect or significantly less than the screening levels. The SSSG sample results from location Celsis 04 for chloroform collected in October 2015 and March 2016 exceeded its NJDEP VIG nonresidential soil gas screening level. No other VOCs were detected in subslab soil gas at concentrations greater than the screening levels. VR Results TCE was detected in one of the VR samples collected in October The observed TCE level was over 170 times less than the soil gas screening level. There were no screening level exceedances in the VR samples collected during the October 2015 sampling event. VR samples were not collected in March 2016 as the SSD system was not operational due to shutdown testing. IA Results The AOC 2 COPCs were not detected in any of the IA samples, including the samples collected in March 2016 when the SSD system was turned off. Benzene and ethylbenzene exceeded screening levels in October 2015 and March The IA levels of these constituents were likely from an indoor source and not the VI pathway as demonstrated by the absence of these chemicals in the SSSG. The March 2016 SSD system shutdown testing results showed no levels of concern for the AOC 2 COPCs or other contaminants that can be attributed to the VI pathway. These results suggest that system termination may be appropriate. Another SSD system shutdown followed by the same sampling regime is planned for July 2016 to evaluate temporal variability. If this second SSD system shutdown monitoring event shows no COPCs attributable to VI above VI screening levels, a recommendation for termination of the SSD system will be made. Campus Plaza 4 Campus Plaza 4 does not have a SSDS. Samples were collected in March A supplemental IA sampling event was completed in May 2016 to confirm and further ES-3

12 investigate slightly elevated TCE levels observed in the March 2016 IA samples. The results from the March and May 2016 sampling events are summarized below. SSSG Results TCE concentrations in SSSG samples collected in March 2016 exceeded the nonresidential soil gas screening level at two of five sample locations. The recent TCE levels are similar to those that have been observed previously. No other analytes had SSSG levels greater than screening levels. IA Results TCE was detected at four of the six indoor air locations sampled in March 2016). Two of the indoor air locations (CP4-2 and CP4-4) had TCE concentrations that exceeded the NJDEP screening level of 3 µg/m 3. The exceedances of the TCE screening level were unexpected based on the TCE results from two previous sampling events (September 2014 and January 2015) when TCE was not detected. Following evaluation of the March 2016 results, a supplemental indoor air sampling event was performed in May An inspection of Campus Plaza 4 was performed on 21 April 2016 to identify any indoor source of TCE and to determine additional sampling locations to fill spatial gaps. The inspection focused on the warehouse space located behind the office space where sample CP4-4 was collected. A photo-ionization detector (PID) was used during the inspection to identify areas with elevated VOCs. The highest PID readings were observed in the warehouse space behind CP4-4 suggesting that the material stored in that space could be the TCE source. IA samples were collected from five new locations plus the four existing locations which contained detected levels of TCE in the March 2016 samples. TCE was detected in all of the indoor air samples collected in May TCE concentrations ranged from 8.6 µg/m 3 at CP4-1 to 150 µg/m 3 at CP4-12. These results provide additional evidence that a TCE source exists within the warehouse space where CP4-12 was collected. The data from the March 2016 and the supplemental May 2016 sampling events for Campus Plaza 4 show that while the VI pathway could be contributing to the TCE levels in IA to a limited degree, it is clear that a background (tenant) source is present within the building. The March and May 2016 sample results have been shared and discussed with Federal Business Center (FBC), the owner of Campus Plaza 4. A carbon filtration system has been installed by FBC in the warehouse space where CP4-12 was collected and the number of hourly air exchanges for this space has been increased. USACE s next sampling event for Campus Plaza 4 is planned for the winter of ES-4

13 Groundwater AOC 6 One building within AOC 6 ( Fernwood) is being monitored. USACE installed a subslab vapor mitigation system on October 2, 2009 to address VOCs in soil gas. The site COPCs (TCE and vinyl chloride) were either non-detect or were detected at levels that were less than the nonresidential screening levels. In April 2011, PCE and TCE were detected in SSSG at concentrations greater than NJDEP VIG screening levels at the same sample location. However, neither TCE nor PCE were detected above NJDEP VIG screening levels for indoor air. This indicates that while TCE and PCE do not pose health risks in indoor air, the remaining concentrations of both constituents in soil gas should continue to be monitored (Table ES-2) The subslab vapor mitigation system was modified in March 2011 from an active (electric) system to solar powered system. Annual inspections of the subslab vapor mitigation system are performed to ensure that the system is operating properly (see Appendix C). USACE conducts a monthly visual inspection including measuring the vacuum at each vapor extraction point to verify the system is operating. USACE recommends annual inspection of the passive treatment system to ensure the system is properly functioning with sampling every 5 years. The next sampling round is scheduled for Groundwater AOC 8 A/B Three U.S. Environmental Protection Agency (EPA) buildings (Buildings 10, 200, and 205) were sampled within Groundwater AOC 8 A/B during October 2015 and March Buildings 10, 200, and 205 have a SSDS in place. Table ES-3 presents a summary of the recent sampling results along with proposed actions for Groundwater AOC 8. Building 10 VOCs have not been migrating into the indoor air from the subslab at levels of concern. This is due to the effectiveness of the SSDS. Semi-annual monitoring of the remedial system has demonstrated that the system is operating properly. ES-5

14 SSSG Results There were no VOCs detected above the nonresidential screening levels in the samples collected in October 2015 and March 2016 sampling events at Building 10. IA Results There were no VOC concentrations detected in the indoor air samples collected in October 2015 and March 2016 above the site-specific or NJDEP VIG screening levels. TCE was not detected in any of the indoor air samples. USACE recommends reducing the sampling frequency in Building 10. The next sampling event is planned for the winter of Assuming the results from the next sampling event are consistent with previous events and VOCs are not a concern, it will be recommended that the Building 10 sampling frequency will be reduced to once every five years with annual inspections to ensure the SSD system is operating properly. USACE performed an optimization study (Geosyntec, 2015b) of the mitigation system in May 2015 to determine the proper flow-rate and operation of the mitigation system and need for future sampling (see Appendix D). As a result of the optimization evaluation, a reduction in the SSD system operation is appropriate. There is a potential for fluctuations in the building pressure over time that could potentially result in intermittent, short-term TCE concentrations of concern. Therefore, ongoing operation at a reduced level is prudent. Of the three vent pipes that comprise the SSD system, SSD-2 has the greatest mass flux so it would be appropriate to focus SSD optimization efforts at SSD-2. It is recommended that the current SSD system be modified to operate with only extraction point SSD-2. NJDEP provided comments on the Building 10 optimization study on 14 July 2015 (see Appendix D). NJDEP indicated that the proposed modification to the SSD system is acceptable and provided recommendations regarding the next steps in the system optimization process. However, EPA has yet to approve the proposed changes to the SSDS. Building 200 Analytical data from October 2015 and March 2016 shows that while there were detections of TCE above its nonresidential screening level for subslab soil gas, TCE in the indoor air was less than the nonresidential screening level. SSSG Results During October 2015, TCE was detected in soil gas above its nonresidential screening level. The March 2016 TCE concentration was equal to its ES-6

15 nonresidential SSSG screening level. No other VOCs were detected above their screening levels for subslab soil gas. IA Results TCE was either not detected or was detected at levels that were less than its nonresidential screening level in the October 2015 and March 2016 samples. None of the other VOCs had concentrations detected above the nonresidential site-specific or the NJDEP VIG screening levels at the indoor air locations. Based on the analytical data from October 2015 and March 2016 the incomplete exposure pathway via subslab soil gas is likely due to the presence of the SSDS. An optimization study of the Building 200 SSD system was conducted in August 2015 (see Appendix E). The conclusion of the study was that the existing fan could be replaced with a smaller, energy efficient fan. NJDEP was notified of the fan replacement in a letter dated 11 February 2016 (see Appendix E). The fan was replaced on 15 April 2016, after the March 2016 sample collection effort. It is recommended that monitoring at Building 200 continue at the same semi-annual frequency for the next year. Building 205 An optimization study of the Building 205 SSD system was conducted in the summer of The Building 205 SSD system consists of nine extraction fans. Per the optimization study and prior to the October 2015 sampling event, eight of the fans were capped and shutdown leaving only fan #3 operational. The October 2015 samples were collected with only fan #3 running. Subsequent to the October 2015 sampling and prior to the March 2016 sampling, it was decided to uncap and operate fan #8 for enhanced radon (non-dod issue) capture. The March 2016 samples were collected with fans #3 and #8 running. The results from the October 2015 and March 2016 sampling events are summarized below. SSSG Results During the October 2015 and March 2016 sampling events, the analytical results of subslab soil gas indicated that TCE was detected at every location. TCE exceeded its nonresidential SSSG screening level at two locations. Additionally, chloroform was detected above its nonresidential NJDEP VIG screening level at one location in October 2015 and March There were no other VOC concentrations detected above NJDEP VIG nonresidential screening levels in the subslab soil gas samples. ES-7

16 IA Results TCE was not detected in any of the samples collected during October 2015 and March There were no other VOCs detected in indoor air samples above the site-specific or NJDEP VIG screening levels. Since TCE was not detected in indoor air the VI exposure pathway is incomplete and successfully mitigated. It is concluded that the modified SSD system at Building 205 has successfully addressed the potential for VI. USACE recommends reducing the sampling frequency in Building 205. The next sampling event is planned for the winter of Assuming the results from the next sampling event are consistent with previous events and VOCs are not a concern, it will be recommended that the Building 205 sampling frequency be reduced to once every five years with annual inspections to ensure the SSD system is operating properly. ES-8

17 FIGURES

18 Exclusion Area 200-BG !! (?k (! 200-SG SG VI pathway may need to be re-evaluated if the building use changes. AOC3 Building Monitoring Schedule 010-SG-04 Building??! (! Next Planned Sampling Event 010-BG-01 Notes k AOC8AB 205-SG AOC Fieldcrest Winter 2017 Ongoing annual inspections of SSDS. 165 Fieldcrest July 2016 Second SSDS shutdown testing event. Campus Plaza 4 Building 10 Winter SG Winter SG-15!? (? (! SG Building SG !? ( Ongoing annual inspections of SSDS. SAI ? (! Building 205 Building 209 AOC Fernwood? (! k Winter EPA Building 200 Summer EPA Building 205 Winter VR-02 Home BG-01 Amax VR BG-01 AOC 8 EPA Building 10 Building 150 Building 151 Pepper 01!? ) " 165-BG-01 k?celsis 04 Building 165! 165-5!? k165-3 (! (!! ( k (!! (!? 160-1! (!? ( Building 160! ( k!!!? ( STEEL-1!? CLAY MOL (Rnd1) (Roof) (Outside) (! "! ) (!?! ( (! k 165-BG-01 CP4-10 CP4-8 AOC2 CP4-4 CP4-5 CP4-BG-01 CP4-7 Building 427 CP4-SG-3 CP4-1 (Campus (!! (!! Plaza 4 (!?!?! ( k! (! (!?!! (? CP4-6!?! (! ( (! CP4-SG-5 AOC9 Campus Plaza 5 CP4-2 CP4-SG-4 AOC8C CP4-SG-6 CP4-9 CP4-SG-2 CP4-12 CP4-11 AOC8D Building 424 AOC7 Building 423 AOC7 AOC7 AOC4B AOC4A AOC1 102FERN FERN-SG FERN FERN-SG-03!? (! 102FERN FERN-SG-02 AOC10 102FERN-01! (? (! 102FERN-SG-01 Legend k Ambient Air Sample Locations ( Indoor Air Sample Locations!!? Subslab Soil Gas Sample Locations ) Vapor Recovery Sample Locations " Groundwater AOC Boundary Building With Subslab Depressurization System Building Screened Out of Investigation Based on Groundwater Data Building Requiring No Further Action Based on Soil Gas and Indoor Air Data Building With On-Going Monitoring Boundary Exclusion Area 300 DOD Source Removal Areas Area4 (Capped - not evaluated) Source: Aerial Photos from NJ Imagery on njwebmap.state.nj.us/ njimagery/natural dated Document Name: IAQ12_ES-1_Program-Overview_ FERN-SG-05!?! ( Building 102!? (! 102FERN FERN-05? (! k 102FERN-06 AOC6A AOC6C AOC6B µ Scale in Feet U.S. Army Corps of Engineers Site, Edison, NJ 600 FIGURE ES-1 INDOOR AIR QUALITY PROGRAM OVERVIEW

19 TABLES

20 Table ES-1 Groundwater AOC 2 Sampling Result and Proposed Action Summary IAQ Report #12 Building Results Summary Proposed Action 160 Fieldcrest The subslab vapor mitigation system was inspected to determine that the system was working properly. A copy of the annual inspection report is located in Appendix A (Geosyntec, 2016a). Continue annual inspections of the subslab vapor mitigation system with 5-year sampling frequency. The next sampling event is scheduled for Per the Work Plan presented in Appendix B, SSDS shutdown testing was conducted in March A focused sampling event was completed one week after SSDS shutdown and a complete sampling event was completed four week after SSDS shutdown. 165 Fieldcrest SSSG Results None of the SSSG sample results for the AOC 2 COPCs were greater than the soil gas screening levels. There was a shutdown (intentional) of the SSD system during the March 2016 sampling. Even during this shutdown, the SSSG results were not a concern for the site COPCs as they were either nondetect or significantly less than the screening levels. The SSSG sample results from location Celsis 04 for chloroform collected in October 2015 and March 2016 exceeded its NJDEP VIG nonresidential soil gas screening level. No other VOCs were detected in subslab soil gas at concentrations greater than the screening levels. VR Results TCE was detected in one of the VR samples collected in October The observed TCE level was over 170 times less than the soil gas screening level. There were no screening level exceedances in the VR samples collected during the October 2015 sampling event. VR samples were not collected in March 2016 as the SSD system was not operational due to shutdown testing. The March 2016 SSD system shutdown testing results showed no levels of concern for the AOC 2 COPCs or other contaminants that can be attributed to the VI pathway. These results suggest that system termination may be appropriate. Another SSD system shutdown followed by the same sampling regime is planned for July 2016 to evaluate temporal variability. If this second SSD system shutdown monitoring event shows no COPCs attributable to VI above VI screening levels, a recommendation for termination of the SSD system will be made. IA Results The AOC 2 COPCs (TCE and VC) were not detected in any of the IA samples even the samples collected in March 2016 when the SSD system was turned off. Benzene and ethylbenzene exceeded screening levels in October 2015 and March The IA levels of these constituents were likely from an indoor source and not the VI pathway as demonstrated by the absence of these chemicals in the SSSG. Samples were collected in March A supplemental IA sampling event was completed in May 2016 to confirm and further investigate slightly elevated TCE levels observed in the March 2016 IA samples. Campus Plaza 4 SSSG Results - TCE concentrations in SSSG samples collected in March 2016 exceeded the nonresidential soil gas screening level at two of five sample locations. The recent TCE levels are similar to those that have been observed previously. No other site COPCs had SSSG levels greater than screening levels. IA Results - TCE was detected at four of the six indoor air locations sampling in March Two of the indoor air locations (CP4-2 and CP4-4) had TCE concentrations that exceeded the NJDEP screening level. The exceedance of the TCE screening level at CP4-4 was unexpected based on the TCE results from two previous sampling events (September 2014 and January 2015) where TCE was not detected. Following evaluation of the March 2016 results, a supplemental indoor air sampling event was performed in May IA samples were collected from five new locations plus four existing locations, all of which contained detected levels of TCE in the March 2016 samples. TCE was detected in all of the indoor air samples collected in May TCE concentrations ranged from 8.6 µg/m3 at CP4-1 to 150 µg/m3 at CP4-12. These results provide additional evidence that a TCE source exists within a warehouse space within Campus Plaza 4. The data from the March 2016 and the supplemental May 2016 sampling events for Campus Plaza 4 show that while the VI pathway could be contributing to the TCE levels in IA to a limited degree, it is clear that a background (tenant) source is present within the building. The March and May 2016 sample results have been shared and discussed with the property owner. Mitigation measures have been implemented by the property owner. USACE s next sampling event for Campus Plaza 4 is planned for the winter of 2017 FUDS Project Number C02NJ IAQ Report #12_ES Tables_Final 1 of 1 9/28/2016

21 Table ES-2 Groundwater AOC 6 Sampling Result and Proposed Action Summary IAQ Report #12 Building Results Summary Proposed Action Fernwood The subslab vapor mitigation system was inspected at Fernwood and it was determined that the system was working properly. A copy of the annual inspection report is located in Appendix C (Geosyntec, 2016b). Continue annual inspections of the subslab vapor mitigation system with 5-year sampling frequency. USACE continues to conduct a monthly visual inspections including measuring the vacuum at each suction point to verify the system is operating. The next sampling event is scheduled for FUDS Project Number C02NJ IAQ Report #12_ES Tables_Final 1 of 1 9/28/2016

22 Table ES-3 Groundwater AOC 8 A/B Sampling Result and Proposed Action Summary IAQ Report #12 Building Results Summary Proposed Action Building 10 SSSG Results - There were no VOCs detected above the nonresidential screening levels in the samples collected in October 2015 and March 2016 sampling events at Building 10. IA Results - There were no VOC concentrations detected in the indoor air samples collected in October 2015 and March 2016 above the site-specific or NJDEP VIG screening levels. TCE was not detected in any of the indoor air samples. USACE performed an optimization study (Geosyntec, 2015b) of the mitigation system in May 2015 to determine the proper flow-rate and operation of the mitigation system and need for future sampling (see Appendix D). USACE recommends reducing the sampling frequency in Building 10. The next sampling event is planned for the winter of Assuming the results from the next sampling event are consistent with previous events and VOCs are not a concern, it will be recommended that the Building 10 sampling frequency will be reduced to once every five years with annual inspections to ensure the SSD system is operating properly. Building 200 SSSG Resuts - During October 2015, TCE was detected in soil gas above its nonresidential screening level. The March 2016 TCE concentration was equal to its nonresidential SSSG screening level. No other VOCs were detected above their screening levels for subslab soil gas. IA Results - TCE was either not detected or was detected at levels that were less than its nonresidential screening level in the October 2015 and March 2016 samples. None of the other VOCs had concentrations detected above the nonresidential site-specific or the NJDEP VIG screening levels at the indoor air locations. An optimization study of the Building 200 SSD system was conducted in August 2015 (see Appendix E). The conclusion of the study was that the existing fan could be replaced with a smaller, energy efficient fan. NJDEP was notified of the fan replacement in a letter dated 11 February 2016 (see Appendix E). The fan was replaced on 15 April 2016, after the March 2016 sample collection effort. It is recommended that monitoring at Building 200 continue at the same semi-annual frequency for the next year. Building 205 SSSG Results - During the October 2015 and March 2016 sampling events, the analytical results of subslab soil gas indicated that TCE was detected at every location. TCE exceeded its nonresidential SSSG screening level at two locations. Additionally, chloroform was detected above its nonresidential NJDEP VIG screening level at one location in October 2015 and March There were no other VOC concentrations detected above NJDEP VIG nonresidential screening levels in the subslab soil gas samples. IA Results - TCE was not detected in any of the samples collected during October 2015 and March There were no other VOCs detected in indoor air samples above the site-specific or NJDEP VIG screening levels. An optimization study of the Building 205 SSD system was conducted in the summer of The Building 205 SSD system consists of nine extraction fans. Per the optimization study and prior to the October 2015 sampling event, eight of the fans were capped and shutdown leaving only fan #3 operational. The October 2015 samples were collected with only fan #3 running. Subsequent to the October 2015 sampling and prior to the March 2016 sampling, it was decided to uncap and operate fan #8 for enhanced radon (non-dod issue) capture. The March 2016 samples were collected with fans #3 and #8 running. USACE recommends reducing the sampling frequency in Building 205. The next sampling event is planned for the winter of Assuming the results from the next sampling event are consistent with previous events and VOCs are not a concern, it will be recommended that the Building 205 sampling frequency be reduced to once every five years with annual inspections to ensure the SSD system is operating properly. FUDS Project Number C02NJ IAQ Report #12_ES Tables_Final 1 of 1 9/28/2016

23 FUDS Project Number C02NJ INTRODUCTION AND OBJECTIVES Avatar Environmental, LLC (Avatar) evaluated the potential for vapor intrusion (VI) into buildings from contaminated groundwater at the former Raritan Arsenal site in Edison, NJ. This Indoor Air Quality (IAQ) Report #12 is a continuation of the ongoing IAQ monitoring program and was prepared for the U.S. Army Corps of Engineers (USACE) New York and New England Districts under USACE Contract W912DR-13-D-0014, Delivery Order DB03. The objectives of this report are: To summarize and evaluate indoor air, subslab soil gas, and groundwater sampling results at each of the buildings recommended for sampling in Indoor Air Quality Report #11 (Avatar, 2016); To assess whether a complete VI exposure pathway exists; and To provide recommendations on the need for further action. This report presents the analytical results for buildings sampled during October 2015 and March 2016 within Groundwater Areas of Concern (AOCs) 2 and 8 A/B. These Groundwater AOCs have historically exhibited exceedances of the groundwater screening levels in the New Jersey Department of Environmental Protection s (NJDEP) Vapor Intrusion Guidance (VIG) (March 2013). Further, an update is provided in this report for work completed in Groundwater AOC 6. Table 1-1 provides a status of the vapor intrusion concerns for all of the Groundwater AOCs. As recommended in previous reports (Weston, 2006a, 2008a, and 2012), the buildings associated with Groundwater AOCs 4 and 10 do not require any further investigation or action and are not discussed in this report. 1.1 REGULATORY REQUIREMENTS AND AGENCY COORDINATION Activities at the former Raritan Arsenal are being administered by the USACE under the Defense Environmental Restoration Program/Formerly Used Defense Sites (DERP/FUDS) program. The Army is the executive agent on behalf of the Department of Defense (DOD) charged with meeting all applicable environmental restoration requirements at FUDS, regardless of which 1-1 September 2016

24 DOD branch previously owned or used the property. FUDS Project Number C02NJ The Secretary of the Army further delegated the program management and execution responsibility for FUDS to the USACE. In carrying out its responsibilities, the USACE must comply with the DERP statute (10 USC 2701 et seq.), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, 42 USC 9601 et seq.), Executive Orders (EOs) and 13016, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and all applicable DOD (e.g., DOD Management Guidance for the DERP) and Army policies in managing and executing the FUDS program. For FUDS properties not included on the National Priorities List (NPL), the DERP statute requires that response actions addressing DOD hazardous substances, pollutants, and contaminants be conducted in accordance with CERCLA. In all other cases, CERCLA is DOD s preferred framework for environmental restoration. States or tribes are generally the lead regulator for environmental investigations and responses at non-npl FUDS. DOD maintains lead agency authority at non-npl FUDS, coordinates project activities with the lead regulatory agency, and provides notice and opportunity for comment to the appropriate state, tribal, and local authorities. The former Raritan Arsenal property was identified as eligible for action under the FUDS program. The property is not on the NPL. Therefore, the NJDEP is the lead regulatory agency. Under the DERP-FUDS program, only known or potential contamination or hazards on the former Raritan Arsenal attributable to former DOD activities (prior to October 17, 1986) can be addressed. 1.2 BACKGROUND USACE is conducting various Remedial Investigation/Feasibility Study (RI/FS) and Remedial Design/Remedial Action (RD/RA) activities at the former Raritan Arsenal under DERP-FUDS. Through these activities, USACE and NJDEP identified Groundwater AOCs containing volatile organic compounds (VOC) that required evaluation for indoor air quality as presented in the Final Groundwater Natural Attenuation Report (NAR) dated May 2003 (Weston, 2003a) and in 1-2 September 2016

25 FUDS Project Number C02NJ the IAQ Evaluation (Steps One through Four) (Weston, 2005a) and the Final Supplemental Groundwater Data Report (Weston, 2006b). In a March 2003 comment letter concerning the Draft Final Groundwater NAR (Weston, 2002a), NJDEP agreed to natural attenuation as a means of addressing remaining groundwater contamination at the former Raritan Arsenal, provided no VI pathway existed in buildings located above the plumes. NJDEP requested USACE to evaluate potential vapor risks at 151 Fieldcrest Avenue, 165 Fieldcrest Avenue, and other buildings near monitoring well MW-114, which is considered to be a source well of chlorinated solvents located within Groundwater AOC 2 and historically has exhibited the highest detected concentrations of VOCs in groundwater at the former Raritan Arsenal. In May 2003, prior to the initiation of USACE s indoor air program, the property owner at 165 Fieldcrest conducted indoor air sampling that indicated the presence of tetrachloroethylene (PCE). Follow-up indoor air and subslab soil gas samples collected by USACE in June 2003 showed no PCE in indoor air, but did show PCE in the accompanying subslab soil gas samples. A subslab depressurization (SSD) system was subsequently installed jointly by USACE and NJDEP. As a result of the findings at 165 Fieldcrest, awareness of the potential for intrusion of VOCs from soil and/or groundwater into indoor air at the former Raritan Arsenal was heightened. The NJDEP requested that USACE evaluate the VI pathway for all other Groundwater AOCs at the former Raritan Arsenal. In October 2004, NJDEP agreed that assessment of the indoor air exposure pathway at the former Raritan Arsenal should be performed in accordance with the Approach for Evaluating Potential IAQ Impacts (USACE, 2004), referred to hereafter as The IAQ Approach. In accordance with The IAQ Approach, USACE began evaluating buildings located within 100 feet (ft) of the Groundwater AOCs. The Groundwater AOCs originally identified by USACE and NJDEP to be evaluated for IAQ were narrowed from seven to three since the primary contaminants of potential concern (COPCs) 1-3 September 2016

26 FUDS Project Number C02NJ in groundwater are VOCs, mainly trichloroethylene (TCE) and PCE (see Table 1-1). Groundwater AOCs 2, 8, and 10 became the focus and were evaluated due to historical concentrations of VOCs in groundwater. In addition, Groundwater AOC 2 includes a building (165 Fieldcrest Avenue) with sensitive receptors (e.g., daycare center). Subsequent to the evaluation of Groundwater AOCs 2, 8, and 10, Groundwater AOCs 4 and 6 were evaluated for the potential of VI into indoor air in accordance with work plans developed in accordance with the NJDEP s VIG that was current at the time. Table 1-1 presents the VI status for all of the Groundwater AOCs Previous Reporting A series of IAQ reports have been developed over the past decade as part of the ongoing monitoring program. Each report discusses the buildings within the Groundwater AOCs that were evaluated and monitored along with the recommendations based on the analytical results for future action by USACE. The following is a list of the IAQ reports: IAQ Report (Weston, 2005b); IAQ Report #2, (Weston, 2006a); IAQ Report #3, (Weston, 2008a); IAQ Report #4, (Shaw [Shaw Environmental, Inc.], 2009); IAQ Report #5, (Shaw, 2010a); IAQ Report #6, (Shaw, 2010b); IAQ Report #7 (Weston, 2012); IAQ Report #8 (Weston, 2014b); IAQ Report #9 (Weston, 2014a); IAQ Report #10 (Avatar, 2015); and IAQ Report #11 (Avatar, 2016). 1-4 September 2016

27 FUDS Project Number C02NJ Groundwater AOCs Requiring No Further Action for Vapor Intrusion The recommendations from the previous IAQ reports have helped to focus the ongoing IAQ/VI monitoring program. No further action for VI was recommended for the three Groundwater AOCs listed below based on existing analytical data that were below levels of concern. Groundwater AOC 4 IAQ Report #3 (Weston, 2008a) recommended no further action at buildings within Groundwater AOC 4 based on existing groundwater, soil gas, and indoor air levels. NJDEP agreed with this recommendation. Groundwater AOC 6 IAQ Report #4 (Shaw, 2009) recommended no further action for all buildings within Groundwater AOC 6 except for Fernwood Avenue based on existing soil gas and indoor air levels. Installation of a vapor mitigation system was recommended for Fernwood along with monitoring on a 5 year frequency. Groundwater AOC 10 IAQ Report #2 (Weston, 2006a) recommended no further action was necessary at buildings within Groundwater AOC 10 due to insignificant levels of existing soil gas and indoor air levels. NJDEP agreed with this recommendation. Groundwater AOCs 1, 3, 5, and 7 require no further VI action because the groundwater contamination is not related to former DOD activities. There are no volatile contaminants associated with AOC 9. Therefore, there are no VI concerns for AOC IAQ Report #7 Recommendations The following are the recommendations from IAQ Report #7 (Weston, 2012) based on the sampling activities conducted during September 2010 and April 2011 by Groundwater AOC: Groundwater AOC Fieldcrest Avenue Continue annual inspection of the vapor mitigation system with a 5-year sampling frequency for indoor air and subslab soil gas. The next sampling round scheduled for Fieldcrest Avenue Continue semi-annual sampling to monitor and confirm that the vapor mitigation system is operating effectively. Campus Plaza 4 Continue semi-annual sampling to evaluate the potential for the VI pathway. 1-5 September 2016

28 FUDS Project Number C02NJ Groundwater AOC Fernwood Avenue Perform passive sampling of the mitigation system only and submit results in a separate Interim Progress Report and Performance Monitoring Report for the subslab venting system. Groundwater AOC 8 A/B Building 10 Continue semi-annual sampling with an emphasis on ensuring the subslab system is operating properly. Building 18 Continue semi-annual sampling with an emphasis on ensuring the subslab system is operating properly. Building 200 Continue semi-annual sampling with an emphasis on ensuring the subslab system is operating properly. Building 205 Continue semi-annual sampling with an emphasis on ensuring the subslab system is operating properly. Building 209 Continue semi-annual sampling IAQ Report #8 Recommendations The following are the recommendations of IAQ Report #8 (Weston, 2014b) based on sampling activities performed during September 2011 and April 2012 by Groundwater AOC: Groundwater AOC Fieldcrest Continue annual inspections of the vapor mitigation system with 5- year sampling frequency. Last sampling event was conducted in November 2011 and next sampling event is scheduled for Fieldcrest Continued monitoring for the next year (summer 2012 and winter 2013) is recommended to monitor the effectiveness of the subslab mitigation system. USACE took ownership of the vapor mitigation system beginning in February Additionally, USACE began evaluations for potential modifications to the vapor mitigation system beginning in Campus Plaza 4 Since there is a potential for a complete exposure pathway from groundwater to soil gas to indoor air, continued monitoring for this building was recommended. USACE will continue to monitor both subslab and indoor air semiannually (summer 2012 and winter 2013) and then re-evaluate. Additionally, a separate study will be conducted in 2013 to investigate likely sources of indoor air 1-6 September 2016

29 Groundwater AOC 6 FUDS Project Number C02NJ contaminants using isotopes to distinguish between indoor air sources and subslab sources Fernwood Avenue Continue annual inspections of the vapor mitigation system with 5-year sampling frequency. Last sampling event was conducted in June 2012 and next sampling event is scheduled for Continue monthly visual inspection of subslab system by USACE including vacuum checks. Groundwater AOC 8 A/B Building 10 Although there is not a complete exposure pathway, continued semiannual monitoring was recommended (summer 2012 and winter 2013) to confirm proper operation of the mitigation system. After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. Building 18 Sample results from this investigation do not indicate a complete VI pathway. Since the building is no longer in use and has been vacated, USACE and NJDEP agreed that monitoring will not continue. Building 200 USACE will continue to monitor both subslab and indoor air semiannually over the next year (summer 2012 and winter 2013). After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. Continue monthly inspection of subslab system including vacuum and velocity checks to ensure system is working. Building 205 Continued semi-annual subslab and indoor air sampling of this building is recommended for the next year (summer 2012 and winter 2013). After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. Building 209 Although there is not a complete exposure pathway, continued semiannual monitoring of this building is recommended for the next year (summer 2012 and winter 2013). After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary IAQ Report #9 Recommendations The following are the recommendations of IAQ Report #9 (Weston, 2014a) based on sampling activities conducted during October 2012 and February 2013 by Groundwater AOC: Groundwater AOC September 2016

30 FUDS Project Number C02NJ Fieldcrest Continue annual inspections of the vapor mitigation system with 5- year sampling frequency. Last sampling event was conducted in November 2011 and next sampling event is scheduled for Fieldcrest Continued monitoring for the next year (summer 2013 and winter 2014) is recommended to monitor the effectiveness of the subslab mitigation system. USACE will continue evaluations for potential modifications to the vapor mitigation system that began in Campus Plaza 4 Continued monitoring for this building is recommended (summer 2013 and winter 2014) and then re-evaluate. Groundwater AOC Fernwood Avenue Continue annual inspections of the vapor mitigation system with 5-year sampling frequency. Last sampling event was conducted in June 2012 and next sampling event is scheduled for Continue monthly visual inspection of subslab system by USACE including vacuum checks. Groundwater AOC 8 A/B Building 10 Although there is not a complete exposure pathway, continued semiannual monitoring is recommended (summer 2013 and winter 2014) to confirm proper operation of the mitigation system. After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. Building 200 USACE will continue to monitor both subslab and indoor air semiannually over the next year (summer 2013 and winter 2014). After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. Building 205 Continued semi-annual subslab and indoor air sampling of this building is recommended for the next year (summer 2013 and winter 2014). The vapor mitigation system for Building 205 will be evaluated for system optimization. Building 209 USACE recommended no further sampling at this building based on an incomplete pathway from groundwater to SSSG IAQ Report #10 Recommendations The following are the recommendations of IAQ Report #10 (Avatar, 2015) based on sampling activities conducted during September/October 2013 and February 2014 by Groundwater AOC: Groundwater AOC September 2016

31 FUDS Project Number C02NJ Fieldcrest Continue annual inspections of the vapor mitigation system with 5- year sampling frequency. Continue monthly visual inspection of subslab system by USACE including vacuum checks. Last sampling event was conducted in November 2011 and next sampling event is scheduled for Fieldcrest Continued monitoring for the next year (summer 2014 and winter 2015) is recommended to monitor the effectiveness of the subslab mitigation system. USACE will continue evaluations for potential modifications to the vapor mitigation system that began in USACE conducted a partial shutdown of the SSD system in August 2014 in advance of the planned September 2014 sampling event. Upon completion of the September 2014 sampling event, the system was turned back on. USACE and NJDEP are discussing the conditions for system termination. If the data collected in September 2014 and winter 2015 indicate that operation of the SSD is necessary, it is recommended to replace the current SSD blowers with radon fans, which are smaller and more energy efficient. Campus Plaza 4 Continued monitoring for this building is recommended (summer 2014 and winter 2015) and then re-evaluate. Groundwater AOC Fernwood Avenue Continue annual inspections of the vapor mitigation system with 5-year sampling frequency. Last sampling event was conducted in June 2012 and next sampling event is scheduled for Groundwater AOC 8 A/B Building 10 Although there is not a complete exposure pathway, continued semiannual monitoring is recommended (summer 2014 and winter 2015) to confirm proper operation of the mitigation system. After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. USACE will also perform an optimization study of the mitigation system to determine the proper flow-rate and operation of the mitigation system and need for future sampling. Building 18 This building is not discussed in IAQ Report #10 because it has been vacant and was not sampled in summer 2013 or winter EPA reportedly has plans to re-occupy Building 18 at some point in the future. As a result, Building 18 was planned to be sampled in summer 2014 and winter Building 200 USACE will continue to monitor both subslab and indoor air semiannually over the next year (summer 2014 and winter 2015). After a year, the data will be evaluated to determine sampling needs, sampling frequency, and if continued operation of the system is necessary. 1-9 September 2016

32 FUDS Project Number C02NJ Building 205 Continued semi-annual subslab and indoor air sampling of this building is recommended for the next year (summer 2014 and winter 2015). The vapor mitigation system for Building 205 will be evaluated for system optimization. Building 209 USACE recommended no further sampling at this building based on an incomplete pathway from groundwater to SSSG IAQ Report #11 Recommendations The following are the recommendations of IAQ Report #11 (Avatar, 2016) based on sampling activities conducted during September 2014 and January/March 2015 by Groundwater AOC: Groundwater AOC Fieldcrest Continue annual inspections of the vapor mitigation system with 5- year sampling frequency. Continue monthly visual inspections of subslab system by USACE including vacuum checks. Last sampling event was conducted in November 2011 and next sampling event is scheduled for Fieldcrest USACE conducted an intentional, partial shutdown of the SSDS in August 2014 in advance of the planned September 2014 sampling event. The sample results from September 2014 for the AOC 2 COPCs were not a concern even during the partial shutdown. Upon completion of the September 2014 sampling event, the system was turned back on. USACE submitted a work plan (USACE, 2014, see Appendix B) to NJDEP to seek concurrence on a protocol to allow for a full or partial SSD system shutdown at 165 Fieldcrest Avenue, such that the final evaluation phase of the soil vapor intrusion pathway may be completed. The next steps to be taken at 165 Fieldcrest are based on the scenarios outlined in the workplan which are largely dependent on the results of groundwater samples collected in the vicinity of the building in August Campus Plaza 4 Continue sampling but at a reduced frequency (annual sampling rather than semi-annual). The next sampling event is planned for winter 2016 when the data will be re-evaluated, as will the determination of the need and frequency of future sampling events. Groundwater AOC Fernwood Avenue Continue annual inspections of the vapor mitigation system with 5-year sampling frequency. Last sampling event was conducted in June 2012 and next sampling event is scheduled for Groundwater AOC 8 A/B 1-10 September 2016

33 FUDS Project Number C02NJ Building 10 Continuing semi-annual monitoring for another year (summer 2015 and winter 2016) at which time the data will be evaluated to determine the need for further sampling, frequency of sampling, and operation of the mitigation system. USACE performed an optimization study of the mitigation system in May 2015 and the results of the study along with comments from NJDEP can be found in Appendix D. Building 18 USACE will consult with EPA to determine the future use plans for Building 18. If it is determined that Building 18 is planned for near-term future use, another round of semi-annual monitoring will be performed at which time the data will be evaluated to determine the need for further sampling. Building 200 Continue monitoring at the same semi-annual frequency for the next year (summer 2015 and winter 2016). USACE will evaluate the data to determine the proper flow-rate and operation of the mitigation system and need for future sampling. This optimization study was performed in the summer of 2015 (see Appendix E). Building 205 Continue semi-annual subslab and indoor air sampling of this building is recommended for the next year (summer 2015 and winter 2016). USACE will evaluate the data to determine future sampling needs. Building 209 Based on there being no site COPCs above the site-specific screening levels for a number of sampling rounds, the USACE recommended no further sampling at Building 209 in Indoor Air Quality Report #10 (Avatar, 2015). Building 209 will not be discussed in IAQ Report # Current IAQ Report This report (IAQ Report #12) presents the findings of investigations conducted during October 2015 and March 2016, and supplemental indoor air sampling performed in May Table 1-2 summarizes the buildings and tenants included in the investigation described in this report. A number of SSDS optimization studies have been completed for the buildings under evaluation. The goals of the optimization studies are two-fold. The first is to maintain protectiveness which means keeping indoor air concentrations below screening levels with a margin for uncertainty. The second is to reduce energy usage from energy consumed by extraction fan motors and energy consumed by loss of conditioned air. The list below summarizes the sampling events described in this report, the status of the optimization studies, and any changes to the monitoring approach based on the recommendations of the optimization studies. Groundwater AOC September 2016

34 FUDS Project Number C02NJ Fieldcrest a complete round of VI samples was collected from 165 Fieldcrest in October These results are summarized in this report. Subsequent to the October 2015 sampling, NJDEP agreed with the approach in USACE s 2014 workplan that proposed a temporary 30-day shutdown of the SSDS (see Appendix B). USACE received official agreement from NJDEP in an dated February 25, Per the agreed to approach, the SSDS was shutdown for a period of 30 days beginning on March 2, A focused set of SSSG, IA, and AA samples were collected one week after SSDS shutdown on March 9, A complete round of samples was collected from 165 Fieldcrest on March 30, 2016, four weeks after the SSDS shutdown. The shutdown testing samples are summarized in this report. Campus Plaza 4 per the recommendations in IAQ Report #11 (Avatar, 2016), the sampling frequency at Campus Plaza 4 was reduced to annually. Samples were collected from Campus Plaza 4 in March A supplemental IA sampling event was performed in May 2016 to investigate unexpected IA results observed in the March 2016 samples. Groundwater AOC 8 A/B Building 10 USACE submitted an optimization study of the Building 10 SSDS in May 2015 (see Appendix D) that recommended that the current SSDS be modified to operate with only one extraction point. NJDEP indicated that the proposed modification is acceptable and provided recommendations regarding the next steps in the SSDS optimization process. The results of the study and the SSDS modification recommendation was conveyed to EPA. The EPA declined to allow the SSDS modification to be made. Absent any modifications, routine sample collection events were performed in October 2015 and March Building 18 after communication with EPA, it was determined that Building 18 will not be used in the near future. Thus, per the recommendation in IAQ Report #11 (Avatar, 2016), Building 18 was not sampled in October 2015 or March 2016 and will not be discussed in this report. Building 200 an optimization study of the Building 200 SSDS was conducted in the summer of The results of the study along with the recommended SSDS modification were provided to NJDEP in a letter dated February 11, 2016 (see Appendix E). It was recommended that the existing fan be replaced by a smaller fan that would cost a fraction of the electricity required to run the existing fan while maintaining the efficacy of the SSDS. The SSDS modification was not completed in time for the March 2016 sampling event. Thus, the October 2015 and March 2016 samples were collected absent any modification to the SSDS. The fan was replaced on April 15, 2016 and an inspection on April 21, 2016 indicated that the system was operating as designed September 2016

35 FUDS Project Number C02NJ Building 205 an optimization study of the Building 205 SSDS was conducted in the summer of The Building 205 SSDS consists of nine extraction fans. Per the optimization study and prior to the October 2015 sampling event, eight of the fans were capped and shutdown leaving only fan #3 operational. The October 2015 samples were collected with only fan #3 running. Subsequent to the October 2015 sampling and prior to the March 2016 sampling, it was decided to uncap and operate fan #8 for enhanced radon (non-dod issue) capture. The March 2016 samples were collected with fans #3 and #8 running. 1.3 VAPOR MIGRATION PATHWAY This report evaluates the potential migration pathway of VOCs from groundwater and soils to indoor air. Due to their high vapor pressures, VOCs dissolved in groundwater readily volatilize from the groundwater and move by diffusion and advection (which is actually the more dominant mechanism) through the capillary and unsaturated zones of the soil, eventually discharging to the atmosphere at the ground surface. Lateral and vertical migration of soil gas occurs in response to variations in pressure and can be quite complex. For example, high-pressure weather systems tend to keep soil gas in the subsurface, while low pressure weather systems allow the soil gas to move readily into the atmosphere. Variations in soil texture and permeability greatly affect the movement of soil gas, as do the presence of underground utilities and other structures that may act as conduits. In areas where the ground surface is covered by a building or paved surface, VOCs in soil gas can become trapped beneath these structures resulting in a mounding effect. These vapors are capable of entering structures through minute cracks in foundations, pipe, or utility penetrations through the concrete floor slabs or walls, and through foundation drains. Soil gas entry into structures is usually the result of pressure differentials which are mainly caused by indoor-outdoor thermal differences, wind loading on structures, and unbalanced ventilation systems that can result in the depressurization of a building (Hodgson, et al. 1992). Most buildings maintain an indoor air pressure that is often lower than outdoor air. Under this negative pressure, subsurface soil gas may be drawn to cracks in the basement or slab floor and into the building. A building in this situation has an area of influence which may draw subsurface soil gas toward the building slab from surrounding areas September 2016

36 FUDS Project Number C02NJ Many factors influence the rate of soil gas entry into a building at any given time. Increased soil moisture, which often occurs in the spring after the ground thaws and snow melts, can drive soil gas from surrounding areas into the relatively dry soils beneath structures, increasing the potential for vapor infiltration. Heavy rainfall can also result in a lens/layer of clean water at the water table reducing the source soil gas concentrations. Frozen ground can also limit the vertical migration of subsurface gases and increase mounding effects and lateral migration. Under heating conditions, building basements or the first floor above the concrete slab can be under less pressure relative to the surrounding soil (Hodgson, et al. 1992). This is sometimes referred to as the stack or chimney effect, and can greatly increase the rate of soil gas infiltration. For the above reasons, winter and spring conditions tend to promote the infiltration of soil gas into structures and generally represent worst-case conditions. As indicated in Section of the NJDEP VIG (2013), indoor air samples collected from November through March are required prior to making remedial decisions as this timeframe is considered as being most representative of the presumed worst case conditions. 1.4 USACE INDOOR AIR EVALUATION PROCESS The IAQ Approach for the former Raritan Arsenal establishes the priorities for further investigation of potential IAQ impacts (Figure 1-1). The IAQ Approach, which has been agreed to by the NJDEP, is a step-wise approach to evaluate the potential for IAQ impacts from contaminated groundwater and residual soil sources at the former Raritan Arsenal. Steps One through Four of the IAQ Approach are: Step One: Complete preliminary inventory of buildings potentially affected by Groundwater AOC plumes. Step Two: Develop a conceptual model for each Groundwater AOC plume. Step Three: Determine contaminants of potential concern (COPC) for further evaluation by comparing historical groundwater data to Table 2C-GW screening benchmarks from the Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (EPA, 2002) September 2016

37 FUDS Project Number C02NJ Step Four: Prioritize Groundwater AOC plumes to be evaluated for potential VI based on sensitive receptors and historical groundwater data. Expedite an evaluation process where groundwater concentrations are 50 times greater than Table 2C-GW screening benchmarks. It should be noted that going forward, the decision process set forth in the NJDEP VIG will be used to determine the need for expedited review of the potential for VI at the former Raritan Arsenal, if specific Groundwater AOCs and the buildings associated with those AOCs have not yet been evaluated. The information gathered under Steps One through Four provide a basis for Steps Five through Twelve of the IAQ Approach. Step Five: Using existing groundwater quality data, assess whether there is potential for a complete VI pathway from groundwater to indoor air and evaluate the potential IAQ impacts. If groundwater data indicate the potential for VI concerns (i.e., exceed screening criteria), then go to Step Six. Step Six: Conduct subslab soil gas sampling. Step Seven: Compare soil gas concentrations to the subslab soil gas screening benchmarks. Predict concentrations of VOCs in indoor air based on subslab soil gas data. If soil gas data indicate potential exceedance of residential indoor air screening benchmarks, then go to Step Eight. While The IAQ Approach originally required comparison of site-specific data to the EPA Generic Screening Benchmarks for Target Indoor Air Concentrations (EPA Table 2C [EPA, 2002]) criteria, this approach was developed prior to publication of the NJDEP VIG. Moving forward, site-specific data have been, and will continue to be, compared with the most recent screening levels provided in the NJDEP VIG and site-specific risk-based screening levels for select COPCs (see Appendix F). Step Eight: Evaluate indoor air impacts by conducting sampling to determine if indoor VOC concentrations exceed ambient air sample results and/or residential indoor air limits. Identify other buildings for soil gas sampling. Step Nine: Perform confirmatory sampling of subslab soil gas and indoor air at the building (to assess temporal variability and verify the initial findings). Step Ten: If the confirmatory sampling verifies the initial results, evaluate remedial alternatives for the building. Step Eleven: Implement remedy for the building and collect post-remedial indoor air and subslab soil gas samples to document system effectiveness. Step Twelve: Prepare report documenting process and results for the NJDEP September 2016

38 FIGURES

39