949 E 36th Ave., Suite 500 Anchorage, AK 99508, USA 907-762-1500 Fax 907-762-1600 Technical Memorandum Date 25 October 2018 To Gary Fink (AFCEC) From Kevin Maher (Jacobs) Subject 2017 Groundwater Sampling Activities and Results for the PL001 and SS086 Monitoring Areas (Final) INTRODUCTION This technical memorandum presents the results from the 2017 groundwater sampling conducted under U.S. Air Force (USAF) Contract No. FA8903-09-D-8568, Task Order No. 0002. Groundwater samples were collected at 13 monitoring wells at Source Areas PL001 and SS086 in accordance with Alaska Administrative Code (AAC) Title 18, Chapter 75, §335(c) [18 AAC 75.335(c)] (Alaska Department of Environmental Conservation [ADEC] 2017). The location and vicinity of PL001 and SS086 Monitoring Areas are presented on Figure 1 and associated subsites are presented on Figures 2 and 3 (Attachment 1). Subsite boundaries are defined as the point or area where contamination was discovered, whereas the monitoring area boundary incorporates all subsites within a monitoring area. The following attachments are included with this memorandum: • Attachment 1 – site figures • Attachment 2 – groundwater sampling forms • Attachment 3 – field notes • Attachment 4 – 2017 analytical data tables and ADEC laboratory data review checklists • Attachment 5 – waste management documentation • Attachment 6 – ADEC approval letter SOURCE AREA PL001 BACKGROUND The ADEC Contaminated Sites Database file number for Source Area PL001 is 107.38.106. Source Area PL001 comprises approximately 235 acres and contains 13 subsites (Subsites A through M). Source Area PL001 subsites are associated with the former Type III hydrant refueling system (HRS) along the south ramp and Taxiway H (Figure 2), where fuel- contaminated soil was uncovered during excavation and construction in 2005. The Air Force Civil Engineer Center (AFCEC) Documentation of Preliminary Interim Land Use Controls Jacobs Engineering Group Inc. Technical Memorandum Page 2 of 8 (PILUC) for SS086 and PL001 memorandum for record clarifies and documents the boundaries for preliminary interim land-use controls (LUCs) and groundwater monitoring for Source Areas SS086 and PL001, as agreed to by AFCEC and ADEC (AFCEC 2016a). The PL001 Monitoring Area boundary incorporates the entire south loop (Figure 1). SOURCE AREA SS086 BACKGROUND The ADEC Contaminated Sites Database file number 107.38.110 tracks SS086 subsites A through E. The SS086 source areas (approximately 50 acres) are located along the eastern edge of Taxiway Golf (Taxiway G) (Figure 3). In 2011, petroleum-affected soil was discovered during a runway upgrade project to install runway edge lights and construct a 3-meter-wide shoulder at Taxiway G. Past releases of aircraft fuel may have occurred during refueling of aircraft or overflow spillage from aircraft vents (USAF 2014b). Soil contamination within the SS086 Monitoring Area includes diesel-range organics (DRO), residual-range organics (RRO), and polycyclic aromatic hydrocarbons (PAHs) confined to surface and near- surface soil; migration of contaminants to groundwater has not occurred at this time based on groundwater sampling results (USAF 2014b). The SS086 Monitoring Area boundary incorporates the entire area within the main airfield fence (Figure 1). PRIOR GROUNDWATER MONITORING RESULTS In 2015, groundwater samples were collected from the five newly installed monitoring wells in addition to nine existing wells (Figures 2 and 3) and one well requested by USAF (87MW01) for one-time sampling. Occasional low-level detections of DRO, gasoline-range organics (GRO), and volatile organic compounds (VOCs) were identified for two wells associated with PL001 (13MW16 and 19PS23). All 2015 results from the SS086 Monitoring Area wells were nondetect for fuel-related analytes. No fuel-related analytes exceed project screening levels (PSLs) for the historical groundwater samples. Arsenic, iron, and manganese were the only analytes to exceed PSLs (AFCEC 2016b). Arsenic exceeded the PSL of 0.01 milligrams per liter (mg/L) in seven primary and one duplicate sample results from seven monitoring wells with concentration ranges from 0.0105 to 0.0264 mg/L. Manganese exceeded the PSL of 4.3 mg/L in three samples from two monitoring wells, resulting in concentrations ranging from 4.59 to 12 mg/L. Iron exceeded the PSL of 14 mg/L at a concentration of 15.7 mg/L in one sample (AFCEC 2016b). I:\WERC-AFCEE-09\TO02-Eielson PBR\WP\PL001\2017 PL001 TM\PL001 SS086 2017 TM.docx AFC-J07-05WC0902-J02-0008 Technical Memorandum Page 3 of 8 In 2016, four wells contained detections of contaminants of concern, including GRO, DRO, VOCs, and PAHs. Eight other monitoring wells across the study area contained PAHs and/or VOCs in low-level estimated concentrations, as signified using the qualifier J. The only analytes to exceed the PSLs were metals. Four monitoring wells (AFMW01, PL001MW02, PL001MW03, and CMW-1) contained arsenic above the PSLs ranging from 0.0111 to 0.029 mg/L. Arsenic exceedances in these four wells were between 2.7 and 5.4 times the background threshold value (BTV) in groundwater at Eielson Air Force Base (AFB) (USAF 2014a). Two monitoring wells (AFMW01 and CMW-1) also exceeded the PSL for manganese at approximately 1.6 to 3.8 times the BTV (AFCEC 2017) with concentrations ranging from 4.76 to 11.5 mg/L. Fuel-related compound results from the 2015 and 2016 groundwater results are presented on Figures 2 and 3. 2017 GROUNDWATER SAMPLING In 2017, groundwater sampling efforts were conducted in accordance with the Eielson Performance-Based Remediation Programmatic Quality Assurance Project Plan (QAPP) (USAF 2015b) and the 2015 Field Sampling Plan (FSP) (USAF 2015a) for Source Area PL001. The objectives of the sampling efforts were identified during project scoping meetings with the USAF and ADEC. The primary objective described in the FSP is to monitor groundwater within the PL001 south loop and SS086 monitoring boundaries to ensure contaminated groundwater is not migrating out of the south loop (PL001) or main runway (SS086) areas. This goal was accomplished by sampling 13 existing wells. As described in this section, no fuel-related target analytes exceeded PSLs, which implies no significant contamination is migrating out of the south loop (PL001) or main runway (SS086) areas. Figures 2 and 3 present the 2017 sampling locations in relation to the monitoring boundaries. A total of 13 monitoring wells were visited for groundwater sampling during the spring. Groundwater samples were collected using the low-flow sampling technique in accordance with JE-SOP-4000 Low-Flow Groundwater Sampling (Appendix C of USAF 2015a). Groundwater samples were acquired from the screened interval using tubing inserted approximately 1 foot below the static groundwater table and connected to a peristaltic pump at the surface, as specified in the FSP (USAF 2015a). Sample containers were filled once water quality parameters stabilized or a minimum of three submerged well casing volumes I:\WERC-AFCEE-09\TO02-Eielson PBR\WP\PL001\2017 PL001 TM\PL001 SS086 2017 TM.docx AFC-J07-05WC0902-J02-0008 Technical Memorandum Page 4 of 8 were purged. Groundwater sampling forms are provided in Attachment 2. Figures 2 and 3 in Attachment 1 show the locations of all monitoring wells sampled. DEVIATIONS TO THE FIELD SAMPLING PLAN Deviations to the 2015 FSP occurred during the 2017 sample collection effort. These deviations included: • An equipment blank was not collected at PL001, as required. Although a blank was not collected, the results from the groundwater samples were significantly less than the PSL. • Samples were not collected from well 19PS20, similar to the 2015 and 2016 sampling events. Although this well remains in the sampling plan, the well does not produce sufficient quantity of groundwater to be sampled for all parameters. This issue was identified in past reports and the stakeholders have not required action for this issue at this time. 2017 GROUNDWATER RESULTS Groundwater samples were analyzed offsite at EMAX Laboratories, Inc. (EMAX) for GRO, DRO, VOCs, PAHs, and metals, as outlined on Worksheet #17 of the FSP (USAF 2015a). Analytical results were compared to the PSLs presented on Worksheet #15 of the Programmatic QAPP (USAF 2015b). Of the 13 primary groundwater samples and two duplicate samples analyzed by EMAX, no exceedances were reported except arsenic and manganese (Table 1). Groundwater sample analytical results for GRO, DRO, benzene, toluene, ethylbenzene, and xylenes (BTEX) are summarized on Figures 2 and 3 (Attachment 1), and the complete groundwater analytical results are provided in Attachment 4. Although no groundwater samples contained contaminants above the PSLs, six wells (03M03B, 13MW16, 44MW13, AFMW01, AFMW03, and MW-BKG-07) contained low-level estimated detections of GRO, DRO, and/or VOCs, as signified using the qualifier J. One well (13MW16) contained estimated concentrations of PAHs. Five additional wells (09M03, 44M03, AFMW02, PL001MW02, and PL001MW03) contained low-level detections of VOCs; refer to Attachment 4 for complete analytical results. 2017 Metals Exceedances in Groundwater Five monitoring wells (09M03, 13MW16, AFMW01, CMW-1, and PL001MW03) contained arsenic above the PSL. Arsenic in these five wells were between 2.1 and 4.8 times the BTV in groundwater at Eielson Air Force Base (Table 1). I:\WERC-AFCEE-09\TO02-Eielson PBR\WP\PL001\2017 PL001 TM\PL001 SS086 2017 TM.docx AFC-J07-05WC0902-J02-0008 Technical Memorandum Page 5 of 8 A total of 10