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HomeMy WebLinkAboutWQ0036881_Corrective Action Monitoring Report_20160111NORTHROP RECEIVED Division of Water Resources AU6 2' 9 2016 S M ITTAL Date: 11 January 2016 i s^hter Otiality Regional Operations AF36eviile Regional Office To: John Johnston U. S. Environmental Protection Agency Atlanta Federal Center 61 Forsyth Street, SW Atlanta, GA .30303-8960 cc: Rob McDaniel Kurt Batsel North Carolina. Department of The Dextra Group, Inc. Environment and Natural Resources 1205 Johnson Ferry Road, Suite # 136-446 Hazardous Waste Section, Suite 150 Marietta, GA 30068 401 Oberlin Road Raleigh, NC 27605-1358 From: . Michael D. Shannon Phone: 310-332-5915 Manager, Remediation Project Management Email: Michael. Shannon@ngc.com Corporate Environmental Remediation Northrop Grumman Corporation 101 Continental Boulevard MS:.D 12/XE6D21 El -Segundo, CA 90245 Subject/Title: Corrective Action Monitoring Report — October 2015 Semi -Annual Event Former Clifton Precision. Site, Murphy, NC EPA ID No. NCD 044 438 406 We are sending you the above referenced document(s): For your review and. comment XX For your information and file For your -approval For your signature Total number of copies sent: 0 Remarks: Please find attached the October 2015 Semi -Annual Event Corrective Action Monitoring Report for. the former Clifton Precision Site. If you have any questions or comments, please do not hesitate to call me at the number shown above or Kurt Batsel at (770) 578-9696. 1 /VORTMROP 46RUMMAAF 1 Former Clifton Precision Site Murphy, North Carolina Corrective Action Monitoring Report October 2015 .Semi -Annual Event January 2016 Contents Section1 Introduction...........................................................................................................................1 Section 2 Monitoring Summary........................................................................................................1 Section3 Results........................................................................................................................................1 Section 4 Potentiometric Surface Mapping -and Trend Analysis .................................... 2 4..1 Regolith/Transition Zone.................................................................................................................2 4.2 Bedrock Zone......................................................:.....................................................................................2 4.3 Surface Water........................................................................................................................................2 4.4 Private Wells and Spring..................................................................................................................3 4.5 Groundwater Recovery.............................................................................................:.......................3 Figures Figure 1 Site Location Map Figure 2a Corrective Action Monitoring Locations Figure 2b Onsite Well Locations Figure 3 Regolith/Transition Zone Potentiometric Surface Map' Figure 4 Bedrock Zone Potentiometric Surface Map Figure 5 Groundwater Recovery Volumes Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Corrective Action Monitoring Schedule Summary of Hydrogeologic Zones Well Construction and Water -Level Data Regolith/Transition Zone Groundwater Data Summary Bedrock Zone Groundwater Data Summary Surface Water Data Summary Private Well and Spring. Data Summary Quality Assurance/Quality Control Data Summary Groundwater Recovery Data Summary Appendices Appendix A Appendix B Laboratory Reports (Electronic Only) Field Notes d Corrective Action Monitoring Report October 2015 Semi -Annual Event 1 Introduction This Corrective Action Monitoring Report presents the results of groundwater and surface water monitoring performed during the October 2015 semi-annual event at the Former Clifton Precision. Site (site) located near Murphy, North Carolina (Figure 1). This event was conducted during the period of 19 October 2015 through 22 October 2015. The event followed the monitoring plan prescribed in the latest revision of the Corrective Action Monitoring Plan (CDM Smith, April 2009; modified June 9, 2014). Details regarding the site history and background are available in the Resource Conservation and Recovery Act (RCRA) Facility Investigation Report (CDM, August 2013). As outlined in the June 9, 2014 Proposed Corrective Action Monitoring Plan Revisions, remediation interim measures(IMs) including groundwater reinjection and thermal remediation were initiated in 2014 to augment the remedial activities at the site. A brief overview of the activities completed to date is presented below: The former groundwater treatment system was decommissioned for replacement with a new treatment system on 4 August 2014. In general, the new system consists of: • Improved sediment filtration; • An upgraded air stripper; • An Advanced Oxidation Process consisting of ultraviolet (UV) oxidation with hydrogen peroxide addition; • Carbon dioxide injection for pH balance; • Eight reinjection wells for injection for treated water on the other side of Slow Creek; • A direct discharge, to sewer option; and • Advanced automated control. Construction, testing, and troubleshooting of the new groundwater treatment and reinjection system occurred from August 2014 to April 2015. The system was substantially complete and began discharge to the sewer in December 2014 to assess performance. Full system operation with reinjection (no direct discharge to the sewer) began on 20 April 2015 after system performance was confirmed. Installation of a thermal remediation system in the Waste Management Unit B area was initiated in August 2014 after design was complete and approved: Installation was completed in April 2015, and system startup involving the use of underground electrodes to heat the subsurface began on 20 April 2015. The system has continued to operate with minimal interruption since April and is expected to continue into early 2016. 2 Monitoring Summary During this monitoring event, 21 monitoring wells, 4 groundwater recovery wells, 3 surface water stations 3 creek monitoring points, and 1 private well location were 1 Corrective Action Monitoring Report October 2015 Semi -Annual Event sampled. Monitoring wells MW-42 and MW-43 were unable to be located for sampling due to tilling activities by the landowner for the parcel where those wells are located. Water levels were measured in each of the sampled monitoring wells, along with'an additional 25 monitoring wells. The monitoring locations are shown on Figures 2a and 2b, and the monitoring schedule is presented as Table 1. A summary of the hydrogeologic zones referenced in Table 1 is presented as Table 2. The work performed in implementing the monitoring program is consistent with the Field Branches Quality System and Technical Procedures, EPA Region 4, Science and Ecosystem Support Division (SESD), Athens, Georgia. The data collection adhered to the latest revision of the following SESD_ Operating Procedures (SESDPROC): SESDPROC- 010 (Logbooks), SESDPROC-005 (Sample and Evidence Management), SESDPROC-100 (Field pH Measurement), SESDPROC-101 (Field Specific Conductance Measurement),. SESDPROC-102 (Field Temperature SecMeasurement), SESDPROC-105 (Groundwater Level and Well Depth Measurement), SESDPROC-201 (Surface Water Sampling), SESDPROC-203 (Pump Operation), SESDPROC-205 (Field Equipment Cleaning and Decontamination); and SESDPROC-301 (Groundwater Sampling). Collected samples were analyzed for volatile organic compounds (VOCs) by TestAmerica Laboratories in Savannah, Georgia according to SW-846 Method 8260B. The VOC list reported for this monitoring event is a site -specific list containing 49 VOCs. In addition to the groundwater and surface water samples, duplicate samples were collected at a frequency of 10% and submitted to the laboratory as blind duplicates. Field work for this event was performed by Environmental Monitoring Services, LLC, and reporting was done by CDM Smith Inc. 3 Results The data results for the October 2015 semi-annual monitoring event are presented in Tables 3 through 8 as outlined below: • Table 3 presents a summary of water level measurements and calculated groundwater elevations. • Table 4 presents a summary of detected compounds for regolith/transition zone groundwater wells. • Table 5 presents a summary of detected compounds for bedrock zone groundwater wells,.. • Table 6 presents a summary of detected compounds for surface water stations. • Table 7 presents a summary of detected compounds for the private spring (SP- 26). . • Table 8 presents a summary of detected compounds for quality assurance/quality control samples, including the blind field duplicates. I Corrective Action Monitoring Report October 2015 Semi -Annual Event Complete laboratory reports for the October 2015 semi-annual monitoring event are included in a CD format as Appendix A. In addition to groundwater monitoring well sampling, operational data were collected for the three groundwater recovery wells (RW- 3, RW-4, and RW-5) in service. The groundwater recovery data collected since startup of the new groundwater treatment system with full reinjection are summarized in Table 9. 4 Potentiometric Surface Mapping and Trend Analysis 4.1 Regolith / Transition Zone A.potentiometric surface map representing the regolith/transition zone is presented as Figure 3. The groundwater flow patterns in the regolith zone for this event are generally consistent with the flow patterns observed during the RCRA Facility Investigation (RFI). The direction of groundwater flow is to the north and northwest across the site and toward Slow Creek and the alluvial valley. Groundwater flow in the alluvial valley is to the west. The effect of the recovery wells on groundwater flow is evident by the drawdown cone observed in the northwest portion of the site and extending off site to the north. : 4.2 Bedrock Zone A potentiometric surface map representing the conditions in the bedrock zone is presented as Figure 4. The. groundwater flow patterns in the bedrock zone for this event show a pronounced influence across the north portion of the site and extending off site due to the ongoing operation of the onsite recovery wells. 4.3 Surface Water Trichloroethene (TCE) was not detected above the method detection limit (MDL) at Creek Monitoring Points (CMP) 1 and CMP-3 in the October 2015 monitoring. Downstream monitoring location CMP-4 did report TCE above the MDL at a concentration of 2.75 µg/L; however, this concentration is below the federal maximum contaminant level (MCL) for TCE. Surface water sample SW-3 also reported TCE at a concentration of 1.2 µg/L, above -the MDL, but below. the MCL. TCE was not detected above the MDL in either SW-6 or SW-10 in the October 2015 monitoring event. Overall, the VOC distribution along Slow Creek shows lower levels than those observed during the last semi-annual event in April 20IS. 4.4 Private Wells and Spring In August 2012, EPA approved revisions to the Corrective Action Monitoring Plan that adjusted the private well and spring sampling plan. One private spring location, SP-26, was sampled during the annual monitoring in October 2015. A private well location, PW- 16, was also scheduled for annual monitoring. However, the corresponding pump was not functional, and thus a sample could not be obtained. Diagnosis of the well pump at I Corrective Action Monitoring Report October 2015 Semi -Annual Event PW-16 is underway, and this well should be available for sampling during the next annual monitoring event in October 2016. 4.5 Groundwater Recovery ' Figure 5 presents the monthly groundwater recovery volumes for the currently used groundwater recovery wells for the last five years. Construction activities associated with the interim measures limited the operating time of all recovery wells from August 2014 to April 2015. Additionally, flow measurement from the individual recovery wells was disabled from September 2014 to April 2015. Effluent flow measurements were being collected from the sewer totalizer until construction activities were completed. The TCE concentration in recovered groundwater from RW-3 has remained lower and relatively stable since the historical high concentration (8,700 µg/L) was detected in October 2008. The TCE concentration detected during this monitoring event was 58 µg/L. The average flow rate for RW-3 was 2.66 gallons per minute (gpm) over the period of May 2015 through September 2015. The TCE concentration in recovered groundwater from RW-4 for this monitoring event was 880 µg/L. This concentration is within the historical range for this well. The average flow rate for RW-4 was 21.14 gpm over the period of May 2015 through September 2015. RW-5 went online on June 30, 2009. Historical TCE concentrations in recovered groundwater from RW-5 have ranged from a low of 1,700 µg/L.to a high.of.5,300 µg/L (October 2014). The concentration reported during this monitoring event was 3,400 µg/L. The average flow rate for RW-5 was.0.99 gpm over the period of May 2015 through September 201.5. 4 Corrective Action Monitoring Report October 2015 Semi Annual Event Figures �q f �' Ff ( � � \r. � �� � �•� I� 1 u1 Former Clifton { > 1800, •-'� �� r���. � •7 �� , � ( Precision Site � _..f TO NC 141 1" All I /r(/ CC7-7, PEACHTR ECREEK • �` . S � � ( 1� �� t� � [� --.1 y�J pry � �• � ��� , fUS 64 1 ( P111�J 'w 1600 �y s ti�r�so: �a NC 141�-- � �5 So �j j/cs 'ido �•- ` ' �� J ��O 1 v `.a�` f�! Topographic Contour Interval = 50 Feet National Geodic'Vertical Datum, 1929 r = 1,800, L 900 Feet 0 1,800 Feet Town. of Murphy Former Clifton - Prescision Site N 1 w E S l O" Figure 1 Site Location Map October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina 1200 1000 800 400 200 0 12/09 Ar-RW-2/RW-5 —RW-3 —TRW-4 Groundwater reinjection and thermal remediation interim measures initiated - RW-4 & RW-5 extraction system shut down for a temporary brought online period IV ew.groun wa er treatment system brought.online. 12/10 12/11 .12/12 12/13 12/14 12/15 Figure 5: Groundwater Recovery Volumes October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Corrective Action Monitoring Report October 2015 Semi Annual Event Tables Table 1: Corrective Action Monitoring Schedule October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Station Code MW-9 Station Type Screened Re olith Station Location Onsite east site boundary Monitoring Rationale Potentiometric surface mappingX vocs Water Level MW-10 Screened Re olith Onsite north downgradient site boundary Containment monitoring X X MW-11 Open Bore PWR/Bedrock Onsite north downgradient site boundary Containment monitoring X X MW-12 Screened Re olith Onsite site interior, downgradient of source area Source status monitoring X X MW-13 Screened Re olith Onsite northwest downgradient site boundary Containment monitoring X X MW-14R Open Bore Bedrock Onsite northwest clowngradient site boundary Potentiometric surface ma in X MW-17 Screened PWR Onsite southwest upgradient site boundary Sentinel well X* X MW-18 Screened Re olith Onsite southeast upgradient site boundary Potentiometric surface mapping X MW-19R Open Bore Bedrock Onsite southeast upgradient site boundary Potentiometric surface mapping X MW-20 Screened Re olith Onsite site interior VOCs historically unstable X X MW-22 Open Bore PWR/Bedrock Onsite site interior Potentiometric surface mapping X MW-23 Screened Re olith Offsite northern flow area Potentiometric surface mapping X MW-25 Open Bore PWR/Bedrock Offsite northern flow area Potentiometric surface mapping X MW-27 Screened Re olith Onsite east upgradient Potentiometric surface mapping X MW-28 Screened Re olith Onsite north downgradient site boundary Containment monitoring X X MW-29 Screened Re olith Onsite north downgradient site boundary Potentiometric surface mapping X MW-30 Screened Re olith/PWR Onsite north downgradient site boundary Potentiometric surface mapping X MW-31 Screened Re olith/PWR Onsite site interior, downgradient of source area Potentiometric surface mapping X MW-32 Screened Re olith/PWR Onsite site interior, downgradient of source area Source status monitoring X X MW-33 Screened Re olith Offsite, northwestern flow area Offsite status monitoring X X MW-34 Screened Re olith Offsite northern flow area Offsite status monitoring X* X MW-35 Screened Re olith Offsite northwestern flow area Offsite status monitoring X X MW-36 Screened Bedrock Onsite north downgradient site boundary Source status monitoring X X MW-37 Screened Bedrock Onsite west clowngradient site boundary Source status monitoring X X MW-38 Screened Bedrock Onsite west site boundary Potentiometric surface mapping X MW-39 Screened Bedrock Onsite west site boundary Potentiometric surface mapping X MW-40 Screened Bedrock Offsite northwestern flow area Reinjection monitoring X X MW-41 Screened Bedrock Offsite, northern flow area Offsite status monitoring X* X . MW-42 Screened Re olith Offsite, northwestern flow area Offsite status monitoring X* X MW-43 Screened Bedrock Offsite northwestern flow area Offsite status monitoring X* X MW-44 Screened Bedrock Offsite northwestern flow area Potentiometric surface mapping X MW-45 Screened Bedrock Onsite southwest upgradient site boundary Sentinel well X* X MW-46 IScreened Reciolith Offsite northern flow area Potentiometric surface mapping X MW-47 IScreened Bedrock Offsite northern flow area ISentinel well X* X PWR - Partially weathered rock (transition zone) RFI - RCRA Facility Investigation * Annual Monitoring in October VOCs - Volatile organic compounds . RCRA - Resource Conservation and Recovery Act Page 1 of 2 Table 1: Corrective Action Monitoring Schedule October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Station ...6 MW-49 �• Screened Re olith Onsite north site bounTa-ry Potentiometric surface mapping •Level Water X MW-50 Screened Bedrock Onsite north site boundary Potentiometric surface mapping X MW-51 Screened Bedrock Offsite western stream valley Potentiometric surface mapping X MW-52 Screened Re olith Offsite western stream valley Potentiometric surface mapping X MW-53 Screened Bedrock Offsite western stream valley Potentiometric surface mapping X MW-54 Screened Re olith Offsite southwestern area Potentiometric surface mapping X MW-55 Screened Bedrock Offsite southwestern area Potentiometric surface mapping X MW-56 Screened Transition Onsite west site boundary Potentiometric surface mapping X MW-57 Screened Transition Onsite west site boundary Potentiometric surface mapping X MW-60 Screened Rego] ithransition Offsite northwestern flow area Offsite status monitoring X X MW-61 Screened Bedrock Offsite northwestern flow area Offsite status monitoring X X MW-62 Screened Re olith Transition Offsite northern flow area Offsite status monitoring X X MW-63 Screened Bedrock Offsite northern flow area Offsite status monitoring X X RW-2 Screened Reciolith Recovery Onsite recovery system Containment monitoring X X RW-3 Screened Re olith Recovery Onsite recovery system Containment monitoring X X RW-4 Screened Re olith Recovery Onsite recovery system Containment monitoring X X RW-5 Screened Bedrock Recovery Onsite recovery system Containment monitoring X X CMP-1 Creek Monitoring Point Slow Creek upstream of site Background X CMP-3 Creek Monitoring Point Slow Creek adjacent to site Containment monitoring X CMP-4 Creek Monitoring Point Slow Creek downstream of site Containment monitoring X SW-3 RFI Surface Water Station Slow Creek downstream of site Offsite status monitoring X SW-6 RFI Surface Water Station Slow Creek downstream of site Offsite status monitoring X SW-10 RFI Surface Water Station ISlow Creek downstream of site Sentinel station X PW-16 Bedrock Suppi Well loffsite, western flow area Offsite status monitoring X X SP-26 ISpring loffsite, western stream valley Offsite status monitoring X* rvun - ramauy weamerea rocK ttransition zone) KN - RCKA Facility Investigation * Annual Monitoring in October VOCs - Volatile organic compounds RCRA - Resource Conservation and Recovery Act Page 2 of 2 Table 2: Summary of Hydrogeologic Zones October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina ONSITE SOUTHOF AREA HYDROGEOLOGIC ZONE• Muroh Marble Sa ro iie Slow reek AlLuuium Sil. LAY. fo san Cla e SILT to salty SAND { ne o ReMunih ucry fine-grained , ye lowish b own cobble-s, and boulders. from land ur ac to Depth- t� re<d�sh brown it Murphy Coarse -Grained Alluyiurn. ran ing f o 5 to 11S feet. Marble roc fYagment4s (ma be SAND GRAVEL, andy;, silty,'yellow cobbl- shaped from iss+luton orange to grayish black;and silty' ea fhering). SAND./sandy SILT'wtth cobbles, sand well rounded. Transition Partially -Weathered Murphy Partially -Weathered Murphy Thickness ranges from 2 to 90 Marble Marble feet; depth to surface ranges Murphy Marble as described for Murphy Marble as described for Bedrock, from 5 to 115 feet; depth to Bedrock, with alternating with alternating rock/fracture zones; bottom ranges from 16 to 120 rock/fracture zones; .upper fractures upper fractures are usually alluvium or feet. are usually saprolite filled. saprolite filled. �'� < y . 8" tF 4� -{R �.c rja. i�`.. Cam. Yy 4 4 :• { �' h . %i '® �s � J l�fr�'�. �y; t. . �"...1 ,N •.i • x.y r "tt�p. � .-u� y; �' P-ns ` • K S.. S � �! � �'t '� 1`� }{J'rp •ry ���... ', f ' �� � ter.: f1 �'- `it 5 # b'T' -{: } k X - } I.r +1' t .�� �,� i 4r% "• sMr is +�" ;-4. ti s i43 ram*? + d ® an m . a '• ° §° > * - Rock types are listed from most to least frequently observed and are commonly interiayered. Table 3: Well Construction and Water Level Data October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Open Interval Water Date Diameter Total Depth Elevation Feet Feet (10-19-2 Well ..eiWell Type lInstalled I I , Inches I Feet BGS I TOC Feet FromTo DeptFF-TFEM MW- lOnsiteScreened Re oit I 2 25 1623.21 5 25 5.76 ' Surfa 1617.45 MW-10 Onsite Screened Re olith 2 40 1620.35 17.5 37.5 7.14 1,613.21 MW-11 Onsite Open Bore PWR/Bedrock 4 73.5 1620.83 27 73.5 8.10 161273 MW-12 Onsite Screened Re olith 4Nov-88 2 29.5 1633.79 19 29 27.14 1606.65 MW-13 Onsite Screened Re olith 2 29.8 1619.08 9.8 29.8 8.98 1610.10 MW-14R Onsite 0 en Bore Bedrock 6 78 1620.08 42 78 10.44 1 609.64 MW-17 Onsite Screened PWR Nov-88 2 49.5 1631.76 29.5 49.5 6.31 1,625.45 MW-18 Onsite Screened Re olith Nov-88 2 64 1633.79 44 64 14.01 11619.78 MW-19R Onsite Open Bore Bedrock Dec-88 6 74.5 1632.00 66.5 74.5 13.30 1,618.70 MW-20 Onsite Screened Re olith Nov-88 2 15.5 1621.77 5.5 15.5 6.79 1 614.98 MW-22 Onsite Open Bore PWR/Bedrock Dec-88 6 52 1622.07 32 52 7.78 1,614.29 MW-23 Offsite Screened Re olith Mar-91 2 21 1614.56 10 20 2.18 1 612.38 MW-25 Offsite Screened PWR/Bedrock Mar-91 2 41 1615.02 28 38 2.08 1,612.94 MW-27 Onsite Screened Re olith Jul-96 4 72 1636.21 62 72 16.89 1 619.32 MW-28 Onsite Screened Re olith Jul-96 4 36 1618.38 26 36 8.35 11610.03 MW-29 Onsite Screened Re olith Jun-00 2 30 1620.32 20 30 9.33 11610.99 MW-30 Onsite Screened Re olith/PWR Jun-00 2 1 24 1617.80 14 24 NM1 NM MW-31 Onsite Screened Re olith/PWR Jun-00 2 25 1619.58 15 25 7.41 11612.171 MW-32 Onsite Screened Re olith/PWR Jun-00 2 32 1620.90 22 32 9.87 1,611.031 MW-33 Offsite Screened Re olith Jul-06 2 75 1610.85 70 75 NM' NM MW-34 Offsite Screened Re olith Jul-06 2 41 1619.36 36 41 5.36 11614.00 MW-35 Offsite Screened Re olith Jul-06 2 91 1619.22 86 91 7.79 1611.43 MW-36 Onsite Screened Bedrock Jun-06 2 70 1620.77 65 70 40.44 1,580.33 MW-37 Onsite Screened Bedrock Jun-06 2 108 1630.60 101 106 1 22.33 1,608.27 MW738 Onsite Screened Bedrock Jun-06 2 101 1653.92 96 101 42.84 1,611.081 MW-39 Onsite Screened Bedrock 3ul-06 2 161 1650.79 151 161 .29.32 1,621.47 MW-40 Offsite Screened Bedrock Jul-06 2 161.5 1610.95 146.5 156.5 2.50 1,608.45 MW-41 Offsite Screened Bedrock Jul-06 2 159 1618.93 149 159 5.88 1 613.05 MW-42 Offsite Screened Re olith Ma -07 2 28 1610.19 18 28 NM NM MW-43 Offsite Screened Bedrock Jun-07 2 83 1622.64 78 83 NM NM MW-44 Offsite Screened Bedrock Ma -07 2 73 1618.35 68 73 7.03 1,611.32 MW-45 Onsite Screened Bedrock Nov-07 2 95 1631.02 72.5 77.5 7.11 1,623.91 MW-46 Offsite Screened Re olith Ma -07 2 53 1626.19 43 53 12.81 1613.38 MW-47 Offsite Screened Bedrock Ma -07 2 83 1626.46 78 83 13.32 1,613.14 BGS - Below ground surface NM - No measurement TOC - Top of casing Elevation is National Geodic Vertical Datum, 1929 PWR - Partially weathered rock (transition zone) 1- Well filled in approximately two feet below ground surface 2 - Artesian conditions noted Table 3: Well Construction and Water Level -Data October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Date Well CodelWell Type lInstalledl MW-49 I Onsite Screened Re olith Ma -07 Diameter Inches I 2 Total Depth Feet BGS 12 Elevation I TOCDepth 1620.62 Open Interval Water Surfac: Feet Feet• • lElevaticli 7 12 5.97 1 614.65 MW-50 Onsite Screened Bedrock Jun-07 2 82 1620.59 77 82 6.44 1 614.15 MW-51 Offsite Screened Bedrock Nov-07 2 115.5 1602.66 105.5 115.5 1.81 1 600.85 MW-52 Offsite Screened Re olith Nov-07 2 42 1604.88 32 42 1.48 1603.40 MW-53 Offsite Screened Bedrock Nov-07 2 52 1604.93 47 52 1.50 1 603.43 MW-54 Offsite Screened Re olith Jan-08 2 38 1637.61 28 38 1 13.13 1,624.481 MW-55 Offsite Screened Bedrock Jan-08 2 110 1637.41 105 110 14.52 162289 MW-56 Onsite Screened Transition Se -11 2 . 76.5 1644.97 .61.5 76.5 37.30 160767 MW-57 Onsite Screened Transition Se -11 2 90 1640.86 80 90 22.31 1 618.55 MW-60 Offsite Screened Re olith ransition Se -11 2 48 1611.26 38 48 NMZ NM MW-61 Offsite Screened Bedrock Se -11 2 90 1611.58 80 90 NMz NM MW-62 Offsite Screened Re olith Transition Se -11 2 43.5 1614.87 33.5 43.5 2.90 1,611.97 MW-63 Offsite Screened Bedrock Se -11 2 84 1615.17 74 84 2.90 1,612.27 RW-2 Screened Re olith Recovery Au -00 4 42 1624.71 17 37 9.43 1 615.28 RW-3 Screened Re olith RecoveryAu -00 4 42 1620.99 17 37 19.54 1 601.45 RW-4 Screened Re olith Recovery Oct-08 6 65 1627.49 30 60 31.52 1 595.97 RW-5 IScreened Bedrock Recovery Oct-08 6 119 1623.7 64 114 106.66_ 1,517.04 BGS - below ground surface NM - No measurement TOC -Top of casing Elevation is National Geodic Vertical Datum, 1929 PWR - Partially weathered rock (transition zone) 1- Well filled in approximately two feet below ground surface Z - Artesian conditions noted Table 4: Regolith/Transition Zone. Groundwater Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..- Compound • 1,1,1-Tdchloroethane 200 • • 1.3 .22 I • 7.8 0 • • ND • • ND • • 11 • • • 1 •10/20/2015 1.1 ND ND 1,1,2-Trichloro-1,2,2-trifluoroethane NE ND 380 .. 8.7 ND ND 13 1.6 0.334 J ND 1,1-Dichloroethane NE 1.1 77 ND ND ND 27 ND ND ND 1,1-Dichloroethene 7 ND 130. 8.2 ND ND 35. 1.7 ND ND 1,4-Dichlorobenzene 75 ND ND ND ND ND ND ND ND ND 2-Butanone NE ND ND ND ND. ND ND ND ND ND Acetone NE ND ND ND ND ND ND ND ND ND Bromodichloromethane 80* ND ND ND ND ND ND ND ND ND Carbon disulfide NE ND ND ND ND ND ND ND ND ND Chloroform 80* 15 ND ND ND ND ND ND ND ND Chloromethane NE ND ND ND ND ND ND ND ND. ND cis-1,2-Dichloroethene 70 1.5 360 14 ND 2.9 41 3.8 0.503 0.597 Dichlorodifluoromethane (CFC-12) NE ND 45 ND ND ND ND ND ND ND Methyl tert-butyl ether NE ND ND ND ND ND : ND ND ND ND Methylene Chloride 5. ND ND ND ND ND ND ND ND ND Tetrachloroethene 5 2.0 96 6.2 ND ND 27 2.8 0146 J 0.188 J Toluene 1,000 ND ND ND _ ND ND ND ND ND ND trans-1,2-Dichloroethene 100 ND ND ND ND ND ND ND ND ND Trichloroethene 5 41 2200 420 ND ND 370 30 8.05 8.97 Vinyl chloride 2 ND ND ND ND ND ND ND ND ND ug/L - Micrograms per liter. Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank or trip blank at a reportable level.. NE - MCL not established. J - Estimated result, result is less than the RL. ND - Not detected, result is below reporting limit (RL). D - Diluted sample was analyzed because undiluted sample result exceeded calibration range PWR - Partially weathered rock (transition zone_) H - Sample was prepped or analyzed beyond specified holding time NM - Not measured Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. E - Result exceeded calibration range Compounds listed in this table are the VOCs reported above the RL in any sample reported during_ the RCRA Facility Investigation or subsequent testing. NS .- Not Sampled Bold indicates the: detected concentration was greater than the MCL. Table 4: Regolith/Transition Zone Groundwater Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample .. Sample Date 1,1,1-Trichloroethane 200 Regolith ND Regolith NS. .0 Regolith ND Regolith ND Monitoring Well ND Well Recovery W I el 21 18 1,1,2-Trichloro-1,2,2-trifluoroethane NE ND NS 0.763 J 1.31 ND 15 280 1,1-Dichloroethane NE ND NS ND ND ND 1.3 ND 1,1-Dichloroethene 7 ND NS ND 0.900 ND 10 31 1,4-Dichlorobenzene 75 ND NS ND ND ND ND ND 2-Butanohe NE ND NS ND ND ND ND ND Acetone NE ND NS ND ND ND ND ND Bromodichloromethane 80' ND NS ND ND ND ND ND Carbon disulfide NE ND NS ND ND ND ND ND Chloroform .80" ND NS ND ND- ND . .1.1 ND Chloromethane NE ND NS ND ND ND . ND ND cis-1,2-Dichloroethene 70 7.4 NS 1.09 5.07 ND 3.2 31 Dichlorodifluoromethane (CFC-12) NE ND NS ND ND ND ND ND Methyl tert-butyl ether NE ND NS ND ND ND ND ND Methylene Chloride 5., ND NS ND ND ND ND ND Tetrachloroethene 5 ND NS 0.336 J 1.60 ND 7.5 27 Toluene 1,000 ND NS ND ND ND ND ND trans-1,2-Dichloroethene 100 ND NS ND ND ND ND ND Thchloroethene 5 4.3 NS 17.5 18.9 4.1 58 880 Vinyl chloride 2 ND NS ND ND ND ND ND pg« - micrograms per finer ' - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level B - This compound was also detected in a corresponding method blank or trip blank at a reportable level. NE - MCL not established J - Estimated result, result is less than the RL. ND - Not detected, result is below reporting limit (RL). D - Diluted sample was analyzed because undiluted sample result exceeded calibration range PWR - Partially weathered rock (transition zone) H - Sample was prepped or analyzed beyond specified holding time NM - No measurement Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B E - Result exceeded calibration range Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. NS - Not Sampled Bold indicates the detected concentration was greater than the MCL 'Recovery well RW-2 converted to monitoring well and replaced with Recovery Well RW-5. Table 5: Bedrock Zone Groundwater Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample .. Sample Date 1,1,1-Trichloroethane 200 Bedrock ND �� ND -0 • • - • Onsite edrock Bedrock Bedrock Bedrock ND ND ND NS - ND 1,1,2-Trichloro-1,2,2-trifluoroethane NE ND 2.4 ND ND 0.670 J NS ND 1,1-Dichloroethane NE 4.8 11 250 ND 17.4 NS ND 1,1-Dichloroethene 7 12 15 ND ND 10.8 NS ND 1,4-Dichlorobenzene. 75 ND . ND ND ND ND NS ND 2-Butanone NE ND ND ND ND 31.4 J NS ND Acetone NE ND ND ND ND ND NS ND Bromodichloromethane 80" ND ND ND ND ND NS ND Carbon disulfide NE ND ND ND 0.641 ND NS ND Carbon Tetrachloride 5 ND. ND ND ND ND NS ND Chloroform 80" ND ND ND ND ND NS ND Chlorometharie NE ND ND ND ND ND NS ND cis-1,2-Dichloroethene 70. 80 29 1100 ND 227 NS ND Dichlorodifluoromethane (CFC-12) NE ND ND ND ND 0.889 NS ND :. Methyl tert-butyl ether NE ND ND ND ND ND NS ND Methylene Chloride 5 ND ND ND ND ND NS ND Tetrachloroethene 5 7.7 14 220 ND 17.9 NS ND Toluene 1,000 ND ND ND ND ND NS ND trans-1,2-Dichloroethene 100 ND ND ND ND 0.328 J NS ND Trichloroethene 5 170 210 15000 0.243 J 951 NS ND Vinyl chloride 2 ND ND ND ND 12.1 NS ND Ng/L - Micrograms per liter. ` :.Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank ortrip blank at a reportable level. NE - MCL not established. J - Estimated result, result is less than the RL. ND -Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. PWR - Partially weathered rock,(transition zone) Compounds listed in, this table are the VOCs reported above, the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. NS - Not Sampled Bold indicates the detected concentration was greater than the MCL. Table 5: Bedrock Zone Groundwater Data Summary. October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample .. Description��� Sample Dateery 1,1,1-Trichloroethane 200 ND ND ND Bedrock Well 98 1,1,2-Trichloro-1,2,2-trifluoroethane NE ND 0.358 J ND 9.1 1,1-Dichloroethane NE - ND ND 0.551 200 1,1-Dichloroethene 7 ND ND 0.294 J 78 1 AUchlorobenzene 75 ND ND ND ND 2-Butanone NE ND ND ND ND Acetone NE ND 2.90 J ND ND Bromodichloromethane 80* ND ND ND ND Carbon disulfide NE ND ND ND ND Carbon Tetrachloride 5 ND ND ND ND Chloroform 80* ND ND ND ND Chloromethane NE ND ND ND ND cis-1,2-Dichloroethene 70 ND 0.976 11.1 190 Dichlorodifluoromethane (CFC-12) NE ND ND ND ND. Methyl tert-butyl ether NE ND ND ND ND Methylene Chloride 5 ND ND ND ND Tetrachloroethene 5 ND 0.233 J ND 94 Toluene 1,000 ND ND ND ND trans-1,2-Dichloroethene 100 ND ND ND ND Trichloroethene 5 ND 12.4 7.52 3400 Vinyl chloride . 2 ND ND ND ND pg/L - Micrograms per liter. ` - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank or trip blank at a reportable level. NE - MCL not established. J - Estimated result, result is less than the RL. ND - Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. PWR - Partially weathered rock (transition zone) Compounds listed in this table are the VOCs reported above the RL in any sample reported .during the RCRA Facility Investigation or subsequent testing.. Bold indicates the detected concentration was greater. than the MCL. Table 6: Surface Water Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..- . Description .. Compoundi 1,1,1-Trichloroethane 200 ��� Surface Surface Water Water ND ND ND ND Surface Water ND ND 1,1,2-Trichloro-1,2,2-trifluoroethane NE ND ND ND ND ND ND 1,1-Dichloroethane NE ND ND, ND ND ND ND 1,1-Dichloroethene 7. ND ND ND ND. ND ND 1,4-Dichlorobenzene 75 ND ND ND ND ND ND 2-Butanone NE ND ND ND ND ND ND Acetone NE ND ND ND 'ND ND ND Bromodichloromethane 80* ND ND ND ND ND: ND Bromomethane NE ND ND ND ND ND ND Carbon disulfide NE ND ND ND ND ND ND Chloroform 80* ND ND ND ND ND ND Chloromethane NE ND ND ND ND ND ND cis-1,2-Dichloroethene 70 ND ND ND ND ND ND Dichlorodifluoromethane (CFC-12) NE ND ND ND ND ND ND Methyl tert-butyl ether NE ND.' ND ND ND ND ND Methylene Chloride 5 ND ND ND ND ND ND . Tetrachloroethene 5 ND ND ND ND ND ND Toluene 1,000 ND ND ND ND ND ND trans-1,2-Dichloroethene 100 ND ND -ND ND ND- ND Trichloroethene 5 ND ND 2.75 1.2 ND ND Vinyl chloride 2 ND ND ND ND ND ND pg/L - Micrograms per liter. * - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank or trip blank at a reportable level. NE - MCL not established. J - Estimated result, result is less than the RL. Nb - Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs) by Method 826013. NS - Not Sampled Compounds listed in this table are the VOCs reported above the RL in any sample reported during the.RCRA Facility Investigation or subsequent testing. Bold indicates the detected concentration was greater than the MCL. Table 7: Private Well and Spring Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..- .-Bedrock Sample Date Compound 1,1,1-Trchloroethane 200 NS ND 1,1,2-Trichloro-1,2,2-trifluoroethane NE NS 1.3 1,1-Dichloroethane NE NS ND 1,1-Dichloroethene 7 NS ND 1,4-Dichlorobenzene 75 NS ND 2-Butanone NE NS ND Acetone NE NS ND Bromodichloromethane 80* NS ND Carbon disulfide NE NS ND Chloroform 80* NS ND Chloromethane NE NS ND cis-1,2-Dichloroethene 70 NS ND Dichlorodifluoromethane (CFC-12) NE NS ND Methyl tent -butyl ether NE NS ND Methylene Chloride 5 NS ND Tetrachloroethene 5 NS ND Toluene 1,000 NS ND trans-1,2-Dichloroethene 100 NS ND Trichloroethene 5 NS 1.7 Vinyl chloride 2 NS ND pg/L - Micrograms per liter. ' - Total tdhalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank or trip blank at a reportable level. NE - MCL not established. J - Estimated. result, result is.less than the RL. ND - Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. NS - Not Sampled Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. Bold indicates the detected concentration was greater than the MCL. PW-16 could not be accessed during current sampling event, therefore there is no VOC analysis. Table 8: Quality-Assurance/Quality. Control Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..- Onsite ■ Screened Sample Date Regolith/PWR 1,1,1-Trichloroethane 200 1.1 ■ Duplicate 1.7 ■ Onsite - Bedrock Duplicate ND ND ■ Onsite Screened Water Duplicate Bedrock Duplicate ND ND ND ND 1,1,2-Trichloro-1,2,2-trifluoroethane NE 1.6 2.2 ND ND ND ND ND ND 1,1-Dichloroethane NE ND 1.5 ND ND ND ND 250 210 1,1-Dichloroethene . 7 1.7 .2.2 ND ND ND ND ND 68 1,4-Dichlorobenzene 75 ND ND ND 77 ND ND ND ND ND 2-Butanone NE ND ND ND ND ND ND ND ND Acetone NE ND ND ND ND ND ND ND ND Bromodichloromethane 80* ND ND ND ND ND ND ND ND Carbon disulfide NE ND ND. ND ND ND ND. ND ND Carbon Tetrachloride 5 ND ND ND ND ND ND ND ND Chloroform 80* ND ND ND ND ND ND ND ND Chloromethane NE ND ND ND ND ND ND ND ND cis-1,2-Dichloroethene 70 3.8 6.2 ND ND ND ND 1100 -980 Dichlorodifluoromethane (CFC-12) NE ND ND ND ND ND ND ND ND Methyl tert-butyl ether NE ND ND ND ND ND ND ND ND Methylene Chloride 5 ND ND ND ND ND ND ND ND Tetrachloroethene 5 2.8 3.4 ND.' ND ND ND 220 190 Toluene 1,000. ND ND ND ND ND -ND 'ND ND trans- 1,2-Dichloroethene 100 ND ND ND ND ND ND ND ND Trichloroethene .5 30 39 ND ND ND ND 15000 12000 Vinyl chloride 2, ND ND ND ND ND ND ND' ND pg/L - Micrograms per liter. * - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. B - This compound was also detected in a corresponding method blank or trip blank at a reportable level. . NE -:MCL not established. J - Estimated result, result is less than the RL. ND - Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs).by Method 8260B. PWR - Partially weathered rock Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. Bold indicates the detected concentration was greater than the MCL.. Table 9: Groundwater Recovery Data Summary October 2015 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina .... Days]Month/Year- ..- . r. - .. Flow Remarks Operated May 2015 June 2015 July 2015 Operation Ceased August 2014 Operation Ceased September 2010 August 2015 September 2015 Recovery Well RW-3 Month/Year Total Gallons Days Average Flow Remarks Total Gallons Days Average Flow Remarks Operated .. May 2015 133,853 29 3.02 System shutdown due to ground fault 841,979 29 20.16 System shutdown due to ground fault maintenance work 5/16-5/17/2015. maintenance work 5/16-5/17/2015. June 2015 116,593 25 3.24 764,728 25 21.24 July 2015 106,356 31 2.38 976,924 31 21.88 August 2015 1 102,492 1 31 2.30 1 1 994,553 31 22.28 September 2015 Recovery Wei I 101,564 30 2.35 RW-5 1 1 869,344 30 20.12 Total Effluent Month/Year Total Gallons I Days Average Flow Remarks Total Gal ns I lo7 Days Average Flow Remarks Operated gpm 0 perated gpm May 2015 24,744 29 0.59 System shutdown due to ground fault 252 1 0.17 Combined effluent from sewer totalizer maintenance work 5/16-5/17/2015. June 2015 19,275 21 0.64 202 1 0.14 Combined effluent from sewer totalizer July 20151 24,510 19 0.55 No Discharge August 2015 1 49,941 1 31 1.12 1 1 1 1 1 No Discharge September 2015 1 88,742 1 30 2.05 1 1 1 1 1 No Discharge gpm - gallons per minute 1 Operation of RW-5 was disrupted in July 2015 due to level transducer failure. /VORTMROP GRLAMMAM Date: 24 August 2016 To: John Johnston U. S. Environmental Protection Agency Atlanta Federal Center 61 Forsyth Street, SW Atlanta, GA 30303=8960 cc: Rob McDaniel North Carolina Department of Environmental Quality Hazardous Waste Section 1646 Mail Service Center Raleigh, NC 27699-1646 TRANSMITTAL RECEIVED Division of Water ResouroeS AUG 2 9 2M6 Water Ouality Regional operdons Ash2vilie Regional Office Kurt Batsel The Dextra Group, Inc. 1205 Johnson Ferry Road, Suite # 136-446 Marietta, GA 30068 Groundwater Protection Branch Water Quality Regional Operations Section Water Quality Regional Operations Section Asheville Regional Office 1636 Mail Service Center 2090 U.S. Highway 70 Raleigh, NC 27699-1636 Swannanoa, NC 28778 From: Michael D. Shannon Northrop Grumman Corporation on behalf of Northrop Grumman Guidance and Electronics Company, Inc. 101 Continental Boulevard MS: D 12/XE6D21 El Segundo, CA 90245 Subject/Title: Phone: 310-332-5915 Email: Michael. Shannon@ngc.com Corrective Action Monitoring Report — April 2016 Semiannual Event _ Former Clifton Precision Site, Murphy, NC EPA ID No. NCD 044 438 406 We are sending you the above referenced document(s): For your review and comment XX . For your information and file . . For your approval For your signature Total number of copies sent: 0 Remarks: Please find attached the April 2016.Semiannual Event Corrective Action Monitoring Report for the former Clifton Precision Site. If you have any questions or comments, please do not hesitate to call me at the number shown above or Kurt Batsel at (770) 578-9696. } NORTMROR GRL AMMA/V -Former Clifton Precision Site Murphy, North .Carolina Corrective Action Monitoring Report April 2016 Semiannual Event August 2016 l C Contents Section1 Introduction.........................................................................................................................1 Section 2 Monitoring Summary......................................................................................................1 Section3 Results.....................................................................................................................................1 Section4 Summary of Results.....:................................................................................................... 2 4.1 Groundwater.........................................................................................................................................2 4.2 Surface Water........................................:...............................................................................................2 4.3 Private Wells and Spring..................................................................................................................3 Section 5 Potentiometric Surface Mapping and Trend Analysis ................................... 3 5.1 Regolith/Transition Zone...............................................................................................................3 5.2 Bedrock Zone.........................................................................................................................................3 Section 6 Groundwater Recovery..............:................................................................................... 3 Section7 References...................................................................................................................4 Figures Figure 1 'Site Location Map Figure 2a Corrective Action Monitoring Locations Figure 2b Onsite Well Locations Figure 3 Regolith/Transition Zone Potentiometric Surface Map Figure 4 Bedrock Zone Potentiometric Surface Map Figure.5 Groundwater Recovery Volumes Tables Table 1 Corrective Action Monitoring Schedule Table 2 Summary. of Hydrogeologic Zones Table 3 Well Construction and Water Level Data Table 4 Regolith/Transition Zone Groundwater Data Summary Table 5 Bedrock Zone 'Groundwater Data Summary Table 6 Surface Water Data Summary Table 7 Private Well and Spring Data Summary Table 8 Quality Assurance/Quality Control Data Summary Table 9 12 Month Groundwater Recovery Data Summary l . Appendices Appendix A Laboratory Reports (Electronic Only) Appendix B Field Notes 0 Corrective Action Monitoring Report April 2016 Semiannual Event 1 Introduction This Corrective Action Monitoring Report presents the results of groundwater and surface water monitoring performed during the April 2016 semiannual event at the Former Clifton Precision Site (site) located near Murphy, North Carolina (Figure 1). This event was conducted during the period of 25 April 2016 through 28 April 2016. The event followed the monitoring plan prescribed in the latest revision of the Corrective Action Monitoring Plan (CDM Smith, April 2009; modified June 9, 2014). Details regarding the site history and background are available in the Resource Conservation and Recovery Act (RCRA) Facility Investigation Report (CDM, August 2013). 2 Monitoring Summary During this monitoring event,18 monitoring wells, 4 groundwater recovery wells, 3 surface water stations, 3 creek monitoring points, and 1 private well location were sampled. This includes monitoring wells MW-42 and MW-43 and private well PW-16, which are typically sampled only during the October semiannual monitoring event. However, samples were not obtained in October 2015 from these wells due to land owner clearing activities (MW-42 and MW-43) and pump electrical issues (PW-16). Water levels were measured in each of the sampled monitoring wells, along with an additional 23 monitoring wells. The monitoring locations are shown on Figures 2a and 2b, and the monitoring schedule is presented as Table 1. A summary of the hydrogeologic zones referenced in Table 1 is presented as Table 2. The work performed in implementing the monitoring program is consistent with the Field Branches Quality System and Technical Procedures, EPA Region 4, Science and Ecosystem Support Division (SESD), Athens, Georgia. The data collection adhered to the latest revision of the following SESD Operating Procedures (SESDPROC): SESDPROC- 010 (Logbooks), SESDPROC-005 (Sample and Evidence Management), SESDPROC-100 (Field pH Measurement), SESDPROC-101 (Field Specific Conductance Measurement), SESDPROC-102 (Field Temperature Measurement), SESDPROC-105 (Groundwater Level and Well Depth Measurement), SESDPROC-201 (Surface Water Sampling), SESDPROC- 203 (Pump Operation), SESDPROC-205 (Field Equipment Cleaning and Decontamination), and SESDPROC-301 (Groundwater Sampling). Collected samples were analyzed for volatile organic compounds (VOCs) by TestAmerica Laboratories in Savannah, Georgia according to SW-846 Method 8260B. The VOC list reported for this monitoring event is a site -specific list containing 49 VOCsAn addition to the groundwater and surface water samples, duplicate samples were collected at a frequency of 10% and submitted to the laboratory as blind duplicates. Field work for this event was performed by Environmental Monitoring Services, LLC, and reporting was done by CDM Smith Inc. 3 Results The data results for the April 2016 semiannual monitoring event are presented in Tables 3 through 8 as outlined below: Corrective Action Monitoring. Report April 2016 Semiannual Event 1 • Table 3 presents a summary of water level measurements and calculated groundwater elevations. • Table 4 presents a summary of detected compounds for regolith/transition zone groundwater wells. • Table '5 presents a summary of.detected compounds for bedrock zone groundwater wells. • Table 6 presents a summary of detected compounds for surface water stations. • Table 7 presents a summary of detected compounds for the private well sampled during this event. • Table 8presents a summary of detected compounds for quality assurance/quality control samples, including the blind field duplicates. Complete laboratory reports for the April 2016 semiannual monitoring event are included in a CD format as Appendix A. In addition to groundwater monitoring well sampling, operational data were collected for the three groundwater recovery wells (RW- 3, RW-4, and RW-5) in service. Groundwater recovery data collected from May 2015 to April 2016 for these wells is summarized in Table 9. The May 2015 date corresponds to startup of an -upgraded groundwater extraction and treatment system. . 4 Summary of Results 4.1 Groundwater Concentrations detected in onsite and offsite monitoring wells this event are consistent with recent events. In general, monitoring wells show either a stable or declining VOC - trend. Several wells show improving conditions as a result of groundwater reinjection, which was started in April 2015. For example, the following decreasing concentrations of trichloroethene (TCE) have been observed: • MW-13 1,300 micrograms per.liter (µg/L) in April 2013 and now non -detect • MW-28 1,700 µg/L in April 2013 and now 19 µg/L • MW-35 Steady around 40 µg/L from April 2013.to April 2014, now 1.9 µg/L • MW-60 Between 25 and 41 µg/L from April 2013 to April 2015, now 7.3 µg/L • MW-61 Between 33 and 45 µg/L from April 2013 to April 2015, now 8.2 µg/L 4.2 Surface Water No compounds were detected above the laboratory practical quantitation limit (PQL) at any of the surface water locations during this event. TCE was detected at an estimated concentration below the PQL of 0.382 µg/L during this event. The detection of VOCs in _ Slow Creek continues to decline as a result of the new groundwater reinjection system started in April 2015. 2 Corrective Action Monitoring Report April 2016 Semiannual Event 4.3 Private Wells and Spring In August 2012, EPA approved revisions to the Corrective Action Monitoring Plan that adjusted the private well and spring sampling plan. One private well (PW-16) and one spring location (SP-26) are currently scheduled for annual monitoring in October 2016. However since PW-16 was not sampled in October 2015, a sample was collected during the April 2016 event. TCE was not detected at PW-16. 5 Potentiometric Surface Mapping 5.1 Regolith / Transition Zone A potentiometric surface map representing the regolith/transition zone is presented as Figure 3. The groundwater flow patterns in the regolith zone for this event are generally consistent with the flow patterns observed during the RCRA Facility Investigation (RFI). The direction of groundwater flow is to the north and northwest across the site and toward Slow Creek and the alluvial valley. Groundwater flow in the alluvial valley is to the west. The effect of the recovery wells on groundwater flow is evident by the drawdown cone observed in the northwest portion of the site and extending off site to the north. 5.2 Bedrock Zone A potentiometric surface map representing the conditions in the bedrock zone is presented as Figure 4. . The groundwater flow patterns in the bedrock zone for this event show a pronounced influence across the north portion of the site and extending off site due to the ongoing operation of the onsite recovery wells. 6 Groundwater Recovery Figure 5 presents the monthly groundwater recovery rates for the currently used groundwater recovery wells for the last five years. The TCE concentration in recovered groundwater from RW-3 has remained lower and relatively stable since the historical high concentration (8,700 µg/L) was detected in October 2008. The TCE concentration detected during this monitoring event was 240 µg/L. The average flow rate for RW-3_was 2.15 gallons per minute (gpm) over the period of October 2015 through March 2016. The TCE concentration in recovered groundwater from RW-4 for this monitoring event was 410 µg/L. This concentration is within the historical range for this well. The average flow rate for RW-4 was 26.64 gpm over the period of October 2015 through March 2016. Historical TCE concentrations in recovered groundwater from RW-5 have ranged from a low of 1,700 µg/L to a high of 5,300 µg/L (October 2014). The concentration reported. Corrective Action Monitoring Report April 2016 Semiannual Event during this monitoring event was 2,200 µg/L. The average flow rate for RW-5 was 2.13 gpm over the period of October 2015 through March 2016. 7 References Corrective Action Monitoring Plan. CDM Smith, April 2009; modified 9 June 2014. Resource Conservation and Recovery Act (RCRA) Facility Investigation Report. CDM Smith, August=2013. Field Branches Quality System and Technical Procedures: SESDPROC- 010 (Logbooks). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 30 May 2013. Field Branches Quality System and Technical Procedures: SESDPROC- 005 (Sample and Evidence Management). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia,-.29 January 2013. Field Branches Quality System and Technical Procedures: SESDPROC-100 (Field pH Measurement). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 29 January 2013. Field Branches Quality System and Technical Procedures: SESDPROC-101 (Field Specific Conductance Measurement). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 30 August 2012 Field Branches Quality System and Technical Procedures: SESDPROC-102 (Field Temperature Measurement). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 23 October 2014. Field Branches Quality System and Technical Procedures: SESDPROC-105 (Groundwater Level and Well Depth Measurement). EPA Region 4, Science and Ecosystem Support Division, Athens, GeorgiaV29 January 2013 Field Branches Quality System and Technical Procedures: SESDPROC- 201 (Surface Water Sampling). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 28 February 2013. Field Branches Quality.System and Technical Procedures: SESDPROC- 203 (Pump Operation). EPA Region 4; Science and Ecosystem Support Division, Athens, Georgia, 12 September 2013. Field Branches Quality System and Technical Procedures: SESDPROC- 205 (Field Equipment Cleaning and Decontamination). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia,18 December 2015. 4 Corrective Action Monitoring Report April 2016 Semiannual Event Field Branches Quality System and Technical Procedures: SESDPROC- 301 (Groundwater Sampling). EPA Region 4, Science and Ecosystem Support Division, Athens, Georgia, 6 March 2013. Method 8260B: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC%MS), part of Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. US Environmental Protection Agency, December 1996. 5 Corrective Action Monitoring Report April 2016 Semiannual Event Figures Topographic Contour Interval = 50 Feet National Geodic Vertical Datum, 1929 1" = 1 800' 900 Feet 0 1,800 Feet Town of Murphy Former Clifton Prescision Site Smith N W E S Figure 1 Site Location Map April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site . Murphy, North Carolina i, 1W I W E , + MW-11 Ixf, r i "" MW-2R €2W�3 + W -10 S. �� ., •: MW-21 } M 20 rR MW-30, M,r j MW— - ° • RW-2 0 Mw-zs d BMW-22 t MW-36 MW=31 I = i { , � I 1 MW=12. MW-8 MW-i7 + Regolith Monitor Well Bedrock Monitor Well + Transition Monitor Well EE) Regolith Recovery Well Bedrock RecoveryVell Smith Semi -Annual VOC Sampling ® Annual. VOC Sampling O Water Level Only Water levels will also be collected from all well sampling'locations: IB Scale in Feet 32.5 0 65 Figure 2b Onsite Well Locations April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, -North -Carolina 1 Corrective Action Monitoring Report 1 April 2016 Semiannual Event 1 Tables 1 1 1 1 1 1 Table 1: Corrective Action Monitoring Schedule _ April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Station .. MW-9 Screened Regolith Onsite east site boundary Potentiometric surface mapping • Wate X MW-10 Screened Regolith Onsite north downgradient site boundary Containment. monitoring . X. X MW-11 Open Bore PWR/Bedrock Onsite, north downgradient site boundary Containment monitoring X X MW712 Screened Regolith Onsite site interior, downgradient of source area Source status monitoring X X MW-13 Screened Regolith Onsite northwest downgradient site boundary Containment monitoring X X MW-14R Open Bore Bedrock Onsite, northwest downgradient site boundary Potentiometric surface mapping X. MW-17 Screened PWR Onsite, southwest upgradient site boundary Sentinel well X* X MW-18 Screened Regolith . Onsite, southeast upgradient site boundary Potentiometric surface mapping X MW-19R Open Bore Bedrock Onsite, southeast upgradient site boundary Potentiometric surface mapping X MW-20 Screened Regolith Onsite, site interior VOCs historically unstable X X MW-22 Open Bore PWR/Bedrock Onsite, site interior Potentiometric surface mapping X MW-23 Screened Regolith Offsite, northern flow area Potentiometric surface mapping X MW-25 Open Bore PWR/Bedrock Offsite, northern flow area Potentiometric surface mapping X MW-27 Screened Regolith Onsite, east upgradient Potentiometric surface mapping X MW728 Screened Regolith Onsite, north downgradient site boundary Containment monitoring X X MW-29 Screened Regolith Onsite north downgradient site boundary Potentiometric surface mapping X MW-30 Screened Regolith/PWR Onsite north down radient site boundary Potentiometric surface mapping, X MW-31 Screened Regolith/PWR Onsite site interior, downgradient of source area Potentiometric surface mapping X MW732 Screened Regolith/PWR Onsite site interior, downgradient of source area Source status monitoring X X MW-33 Screened Regolith Offsite, northwestern flow area Offsite status monitoring X X MW-34 Screened Regolith Offsite, northern flow.area Offsite status monitoring X* X MW-35 Screened Regolith Offsite, northwestern flow area Offsite status monitoring. X X MW-36 Screened Bedrock Onsite, north downgradient siteboundary Source status monitoring X X MW-37 Screened Bedrock Onsite west downgradient site boundary Source status monitoring X X MW-38 Screened Bedrock Onsite west site boundary Potentiometric surface mapping X .MW-39 Screened Bedrock Onsite west site boundary Potentiometric surface mapping X MW-40 Screened Bedrock Offsite, northwestern flow area Reinjection monitoring X X MW-41 Screened Bedrock Offsite, northern flow area Offsite status monitoring X* X MW-42 Screened Regolith Offsite, northwestern flow area Offsite status monitoring X* X MW-43 Screened Bedrock Offsite, northwestern flow area - Offsite status monitoring X* X MW744 Screened Bedrock Offsite, northwestern flow area Potentiometric surface mapping X MW-45 Screened Bedrock Onsite, southwest upgradient site boundary Sentinel. well X* X MW-46 Screened Regolith Offsite, northern flow area Potentiometric surface mapping X MW-47 IScreened Bedrock lOffsite, northern flow area Sentinel well X* X PWK - Partially, weathered rock (transition zone) RFI - RCRA Facility Investigation * Annual Monitoring in October VOCs - Volatile organic compounds RCRA - Resource Conservation and Recovery Act Page 1 of 2 Table 1: Corrective Action Monitoring Schedule April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Station Code MW-49 I Station Type Screened Regolith IStation Location Onsite north site boundary I Monitoring Rationale Potentiometric surface mapping VOCS Water X MW-50 Screened Bedrock Onsite north site boundary Potentiometric surface mapping X MW-51 Screened Bedrock Offsite western stream valley Potentiometric surface mapping X MW-52 Screened Regolith Offsite western stream valley Potentiometric surface mapping X MW-53 Screened Bedrock Offsite, western stream valley Potentiometric surface mapping X MW-54 IScreened Regolith, Offsite southwestern area Potentiometric surface mapping X MW-55 Screened Bedrock Offsite southwestern area. Potentiometric surface mapping X MW-56 . Screened Transition Onsite west site boundary Potentiometric surface mapping X MW-57 Screened Transition Onsite west site boundary Potentiometric surface mapping X . MW-60 Screened Regolith/Transition Offsite, northwestern flow area Offsite status monitoring X X MW-61 Screened Bedrock Offsite northwestern flow area Offsite status monitoring X X MW-62 IScreened Regolith/Transition Offsite northern flow area Offsite status monitoring X X MW-63 Screened Bedrock Offsite northern flow area Offsite status monitoring X X. -RW-2 Screened Regolith Recovery Onsite, recovery system Containment monitoring -X X RW-3 Screened Regolith Recovery Onsite, recovery system Containment monitoring .X X RW-4 Screened Regolith Recovery Onsite recovery system Containment monitoring X X RW-5 Screened Bedrock Recovery. Onsite recovery system Containment monitoring X X CMP-1 Creek Monitoring Point Slow Creek upstream of site Background X CMP-3 Creek Monitoring Point Slow Creek adjacent to site Containment monitoring X CMP-4 Creek Monitoring Point Slow Creek downstream of site Containment monitoring X SW-3 RFI Surface Water'Station Slow Creek downstream of site Offsite status monitoring X SW-6 RFI Surface Water Station Slow Creek downstream of site Offsite status monitoring X SW-10 RFI Surface Water Station Slow Creek downstream of site Sentinel station X PW-16 Bedrock Supply Well Offsite, western flow area Offsite status monitorin X* X SP-26 lSpring Offsite, .western stream valley Offsite status monitoring X* PWR - Partially weathered rock (transition zone) RFI - RCRA Facility Investigation * Annual Monitoring in October VOCs - Volatile organic compounds RCRA - Resource Conservation and Recovery Act Page 2 of 2 Table 2: Summary of Hydrogeologic Zones April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina * - Rock types are listed from most to, least frequently observed and are commonly interlayered. Table 3: Well Construction and Water Level Data April 2016 Semiannual Event. Corrective Action Monitoring -Report Former Clifton Precision_ Site Murphy, North Carolina Date Diameter Total . Well CodeiWell Type lInstallecli Inches I Feet BGS MW-9 lOnsite Screened Re olith A r-87 2 25 Open Interval Water Surface • . I TOC. . Depth I Elevation 1623.21 5 25 6.55 1,616.66 MW-10 Onsite Screened Re olith Mar-87 2 40 1620.35 17.5 37.5 8.24 1 612.11 MW-11 Onsite Open Bore PWR/Bedrock A r-87 4 73.5 1620.83 .27 73.5 8.21 1 612'.62 MW-12 Onsite Screened Re olith Nov-88 2 .29.5 1633.79 - 19 29 22.67 1 611.12 MW-13 Onsite Screened -Re olith Nov-88 2 29.8 1619.08 9.8 29.8 8.85 1 610.23 MW-14R . Onsite Open Bore Bedrock Dec-88 6 78 1620.08 42 . 78 10.21 11,609.87 MW-17 Onsite Screened PWR Nov-88 2 49.5 1631.76 29.5 49.5 8.62 1 623.14 MW-18 Onsite Screened Re olith Nov-88 2 64 1633.79 44 64 15.06 1 618.73 MW719R Onsite Open Bore Bedrock Dec-88 6 74.5 1632.00 66.5 74.5 14.41 1 617.59 MW-20 Onsite Screened Re olith Nov-88 2 15.5 1621.77 5.5 15.5 7.33 161444 MW-22. Onsite Open Bore PWR Bedrock Dec-88 6 52 1622.07 32 52 8.09 1 613.98 MW-23 Offsite Screened Re olith Mar-91 2 21 1614.56 10 20 1.82 1,612.74 MW-25 Offsite Screened PWR/Bedrock Mar-91 2 41 1615.02 28 38 2.04 1 612.98 MW-27 Onsite Screened Re olith Jul-96 4 72 1636.21 62 72 18.88 1617.33 MW-28 Onsite Screened Re olith Jul-96 4 36 1618.38 26 36 4.18 1 614.20 MW-29 Onsite Screened Re olith 3un-00 2 30 1620.32 20 30 9.41 1 610.91 MW-30 Onsite Screened Re olith PWR 3un-00 2 24 1617.80 14 24 Destroyed MW-31 Onsite Screened Re olith PWR 3un-00 2 25 1619.58 15 25 6.87 1,612.71 MW-32 Onsite Screened Re olith PWR 3un-00 2 32 1620.90 22 32 8.96 1611.94 MW-33 Offsite Screened Re olith 3ul-06 2 75 1610.85 70 75 1.02 1 609:83 MW-34 Offsite Screened Re olith ' Jul-06 2 41 1619.36 36 41 5.25 11614.11 MW-35 Offsite Screened Reciolith 3ul-06 2 91 1619.22 - 86 91 .. 7.87 11611.35 MW-36 Onsite Screened Bedrock 3un-06 2 70 1620.77 65 70 34.51 11,586.26 MW-37 Onsite Screened Bedrock Jun-06 2 108 1630.60 101 106 21.90 11,608.70 MW-38 Onsite Screened Bedrock Jun-06 2 101 1653.92 96 101 41.51 11,612.41 MW-39 Onsite Screened Bedrock Jul-06 2 161 1650.79 151 161 37.42 1,613.37 MW-40 Offsite Screened Bedrock Jul-06 2 161.5 1610.95 146.5 156.5 2.21 11608.74 MW-41 Offsite Screened Bedrock Jul-06 2 159 1618.93 149 159 12.98 1 605.95 MW-42 Offsite Screened Re olith Ma -07 2 28 1610.19 18 28 4.66 1,605.53 MW-43 Offsite Screened Bedrock Jun-07 2 83 1622.64 78 83 18.24 1,604.40 MW-44 Offsite Screened Bedrock Ma -07 2 73: 1618.35 68 73' 7.50 1 610.85 MW=45 Onsite Screened Bedrock Nov-07 2 95 1631.02. 72.5 77.5 8.78 1,622.24 MW-46 Offsite Screened Re olith Ma -07 2 53 1626.19 43 53 14.28 1 611.91 MW-47 Offsite Screened Bedrock May-07 2 83 1626.46 78 83 13.72 1,612.74 MW-49 Onsite Screened Re olith Ma -07 . 2 12 1620.62 7 12 6.17 1,614.45 MW-50 Onsite Screened Bedrock Jun-07 2 82 1620.59 77 82 6.61 1,613.98 MW-51 - Offsite Screened, Bedrock Nov-07 2 115.5 - 1602.66 105.5 115.5 1.98 1600.68 MW-52 Offsite Screened Reciolith Nov-07 2 42 1604.88 1 32 42 1.80 1 603.08 MW-53 Offsite Screened Bedrock Nov-07 -2 52 1604.93 47 52 2.01 1,602.92 MW-54 Offsite Screened Re olith Jan-08 2 38 1637.61 28 38 16.78 11,620.83 MW-55 Offsite Screened Bedrock Jan-08 2 110 1637.41 105 110 15.91 1,621.50 MW-56 Onsite Screened Transition. Se -11 2 ..76.5 1644.97 61.5 76.5 30.04 1 614.93 MW-57 Onsite Screened Transition Se. -11 2 90 1640.86 80 90 22.64 1,618.22 MW-60 Offsite Screened Re olith/Transition Se -11 2 48 1611.26 38 48 Artesian MW-61 Offsite Screened Bedrock Se -11 2 90 1611.58 80 90 0.10 1,611.48 MW-62 Offsite Screened Re olith Transition Se -11 2 43.5 1614.87 33.5 43.5 2.89 1 611'.98 MW-63 Offsite Screened Bedrock Se -11 2 84 1615.17 74 -84 3.04 1,612.13 RW-2 Screened Re olith Recovery Au -00 . 4 42 1624.71 17 37 9.44 1,615.27 RW-3 Screened Re olith Recovery Au -00 4 42 1620.99 17 37 25.00 1,595.99 RW-4 Screened Re olith Recovery Oct-08 6 65 1627.49 30 60 27.08 11,600.41 RW-5 Screened Bedrock Recovery Oct-08 6 119 1623.7 64 114 1 107.96 11,515.74 035 - jseiow ground surrace TOC - Top of casing PWR - Partially weathered rock (transition zone) Elevation is National Geodic Vertical Datum,1929 Table 4: Regolith/Transition Zone Groundwater Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina 1, 1, 1 -Trichloroethane- 200 ND ND ND ND 8 ND ND ND WND ND 1,1,2-Trichloro-1,2,2-tdfluoroethane NE ND 320 ND ND ND 20 0.272 J ND ND 0.425 J 1,1-Dichloroethane NE ND 76 2 ND 7 10 ND ND ND ND 1,1-Dichloroethene 7 ND 100 ND ND 1 18 ND ND ND ND 1,4-Dichlorobenzene 75 ND ND ND ND ND ND ND ND ND ND 2-Butanone NE ND ND ND. ND ND ND ND ND ND ND Acetone NE ND ND ND. Nb ND ND 6.82 ND ND ND Bromodichloromethane 80* 2 ND ND ND ND ND ND ND ND ND Carbon disulfide NE ND ND ND ND ND ND ND ND ND ND Chloroform 80* 16 ND ND ND ND 1.5 ND ND ND ND Chloromethane NE ND ND 4 ND ND ND ND ND ND ND cis-1,27-Dichloroethere' 70 1.1 360 ND 6.0 5.4 38 0.25 J 1.2 ND 0.547 Dichlorodifluoromethane (CFC-12) NE ND ND ND ND ND ND ND ND ND ND Methyl tert-butyl ether NE ND ND ND ND ND ND ND ND ND ND Methylene Chloride . 5 ND ND ND ND ND ND ND ND ND ND Tetrachloroethene 5 1 96 ND ND 3 28 ND ND ND ND Toluene 1,000 ND ND ND ND 1 ND ND ND ND ND trans-1,2-Dichloroethene 100 ND ND ND ND ND ND ND ND ND ND Trichloroethene 5 29 2,000 ND ND 19:0 350 4.74 1.9 ND 7.33 Vinyl.chloride 2 ND ND ND ND ND .2.1 ND ND ND ND pg/L - Micrograms per liter.. *.- Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. J - Estimated.result, result is less than the RL. NE - MCL:not established. Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. ND - Not detected, result is below reporting limit (RL). Compounds listed in this table are the VOCs reported above the RL in an sample reported during the RCRA Facility Investigation or subsequent testing. P P Y P P 9 tY 9 4 9• PWR - Partially weathered rock (transition zone) Bald indicates the detected concentration was greater than the MCL. 'I-- I- - - , _- '_ 11, 4wW_MrMWwNW Table 4: Regolith/Transition Zone Groundwater Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..- .-Sample �� Compoundegolith 1,1,1-Tdchloroethane 200 ND ND • 40 . 15 1,1,2-Trichloro-1,2,2-trifluoroethane NE 0.567 J ND 95 200 1,1-Dichloroethane NE 0.254 J 1.6 6.5 ND 1,1-Dichloroethene 7 0.782 ND 29 16 1,4-Dichlorobenzene 75 ND ND ND ND 27Butanone NE ND ND ND ND Acetone NE ND ND ND ND Bromodichloromethane 80* ND ND ND ND Carbon disulfide NE ND ND ND ND Chloroform 80* ND ND 5.2 ND Chloromethane NE ND ND ND ND cis-1,2-Dichloroethene 70 3.56 2 19 26 Dichlorodifluoromethane (CFC-12) NE ND ND ND ND Methyl tert-butyl ether NE ND ND ND ND Methylene Chloride 5 ND ND ND ND Tetrachloroethene 5 1.28 ND 21 19 Toluene 1;000 ND 1.9 ND ND trans-1,2-Dichloroethene 100 ND ND ND ND Trichloroethene 5 12.8 9.2 240 410 Vinyl chloride 2 ND ND ND ND pg/L - Micrograms per liter MCL - Federal Maximum Contaminant Level NE - MCL not established ND - Not detected,. result is below reporting limit (RL). PWR - Partially weathered rock (transition zone) *. Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). J - Estimated result, result is less than the RL. Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260E Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. Bold indicates the detected concentration was greater than the MCL 'Recovery well RW-2 converted to monitoring well and replaced with Recovery Well RW-5. Table 5: Bedrock Zone Groundwater Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Descriptio 1,1;1-Trichloroethane 200 ND ND ND 90 ND ND ND ND 1,1,2-Trichloro-1,2,2-tdfluoroethane NE ND 1.6 ND ND ND 0.404 J ND ND 1,1-Dichloroethane NE 2.5 4.4 220 ND ND ND 0.442 J 180 1,1-Dichloroethene 7 6.3 6.2 ND ND ND ND ND 53 1,4-Dichlorobenzene 75 ND ND ND ND ND ND ND ND 2-Butanone NE ND ND ND ND ND ND ND ND Acetone NE ND ND ND 5.44 ND ND ND ND Bromodichloromethane 80* ND ND ND ND ND ND ND ND Carbon, disulfide NE ND ND ND 0.487 J ND ND ND ND Carbon Tetrachloride 5 ND ND ND ND ND ND ND ND Chloroform 80* ND ND ND ND ND ND ND ND Chloromethane NE ND ND ND ND ND ND ND ND cis- 1,2-Dichloroethene 70 52 18 1,300 ND ND 1.05 8.69 170 Dichlorodifluoromethane.(CFC-12) NE ND ND ND ND ND ND ND ND Methyl tert-butyl ether NE ND ND ND ND ND ND ND ND Methylene Chloride 5 ND ND ND ND ND ND ND ND Tetrachloroethene 5 5.2 7.6 240 ND ND ND ND 74 Toluene 1,000 ND ND 110 : ND ND .0.225 J ND ND trans-1,2-Dichloroethene 100 ND ND ND ND ND ND 0.271 J° ND Trichloroethene 5 100, 120 15,000 ND 2 8.22 . 7.37 2,200 Vinyl chloride 2 1 ND ND ND ND r77ND77- ND ND ND pg/L - Micrograms per liter. * - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level. J - Estimated result, result is less than the RL. NE - MCL not established. Samples analyzed for 49 volatile organic compounds (VOCs) by Method 826013. Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility ND - Not detected, result is below reporting limit (RL). Investigation or subsequent testing. PWR - Partially weathered rock (transition zone) Bold indicates the detected concentration was greater than the MCL. Table 6: Surface Water Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample ..• Sample Datel CompoundDescription / 1, 1, 1 -Trichloroethane 200 Surface Water Surface Water Surface Water ND Surface Surface Water Water ND ND i Surface Water . ND. ND. ND 1,1,2-Trichloro-1,2,2-tdfluoroethane NE ND ND ND ND ND ND 1,1-Dichloroethane NE ND ND ND ND ND ND 1,1-Dichloroethene 7 ND ND ND ND ND ND 1,4=Dichlorobenzene 75 ND ND ND ND ND ND 2-Butanone NE. ND .-'ND ND ND. ND ND Acetone NE ND ND ND ND ND ND Bromodichloromethane 80* ND ND ND ND ND ND Bromomethane NE ND ND ND ND ND ND Carbon disulfide NE ND ND .. ND ND ND ND Chloroform 80* ND. ND ND ND ND ND Chloromethane NE ND ND ND ND ND ND cis-1,2-Dichloroethene 70 ND ND ND. ND' ND ND Dichlorodifluoromethane (CFC-12) NE ND ND ND ND ND ND. Methyl tert-butyl, ether NE ND ND ND ND ND ND Methylene Chloride 5 ND ND ND ND ND ND Tetrachloroethene 5 ND ND ND ND ND ND Toluene 1,000 ND' ND ND ND ND ND trans-1,2-Dichloroethene 100 ND ND ND ND ND ND Trichloroethene 5 ND ND 0.382 J ND ND ND Vinyl chloride 2 ND ND : ND ND ND ND pg/L - Micrograms per liter. * - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL - Federal Maximum Contaminant Level.. J - Estimated result, result is less than the RL. NE - MCL not established. Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. ND - Not detected, result is below reporting.limit (RL). Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility NS - Not Sampled Investigation or subsequent testing. Bold indicates the detected concentration was greater than the MCL: Table 7: Private Well Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Sample .-Bedrock Sample Compound. .. Date .. ND 1,1,1-Trichloroethane 200 1,1,2-Trichlor6-1,2,2-tdfluoroethane NE ND 1,1-Dichloroethane NE . ND 1,1-Dichloroethene 7 ND 1,4-Dichlorobenzene 75 ND 2-Butanone NE ND Acetone NE ND Bromodichloromethane 80* ND Carbon disulfide NE ND Chloroform 80* ND Chloromethane NE ND cis-1,2-Dichloroethene 70 ND Dichlorodifluoromethane (CFC-12) NE ND Methyl tert-butyl ether NE ND Methylene Chloride 5 ND Tetrachloroethene 5 ND Toluene 1,000 ND trans-1,2-Dichloroethene 100 ND Trichloroethene 5 ND Vinyl chloride 2 ND pg/L - Micrograms per liter. * - Total trihalomethanes (chloroform + bromodichloromethane + dibromochloromethane + bromoform). MCL Federal Maximum Contaminant Level. Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. NE - MCL not established. Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. ND - Not detected, result is below reporting limit (RL). Bold indicates the detected concentration was greater than the MCL. Table 8: Quality Assurance/Quality Control Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report. Former Clifton Precision Site Murphy, North Carolina .. 'I msm= ND ■ ■ ND ND ND ND. ■ ND ■ ND ND 1,1,1-Trichloroethane 1,1,2-Trichioro-1,2,2-trifluoroethane ND ND ND ND ND ND ND ND 1,1-Dichloroethane ND ND 220 230 2.5 2.7 ND ND 1,1-Dichloroethene ND ND ND ND 6.3 5.4 ND ND 1,4-Dichlorobenzene ND ND ND ND ND ND ND ND 2-Butanone ND ND ND ND ND ND ND ND Acetone ND ND ND ND ND ND ND ND Bromodichloromethane ND ND ND ND ND ND ND ND Carbon disulfide ND ND ND ND ND ND ND ND Carbon Tetrachloride ND ND ND ND ND ND ND ND Chloroform ND ND ND ND ND ND ND ND Chloromethane ND ND ND ND ND ND ND ND cis-1,2-Dichloroethene ND ND 1,300 1,300 52 49 ND ND Dichlorodifluoromethane (CFC-12) ND ND ND ND ND ND ND ND Methyl tert-butyl ether ND ND ND ND ND ND ND ND Methylene Chloride ND ND ND ND ND ND ND ND Tetrachloroethene ND ND 240 220 5.2 4.2 ND ND Toluene ND ND 110 260 ND ND ND ND trans-1,2=Dichloroethene ND ND ND ND ND ND ND ND Trichloroethene 2 1.7 1 15,000 14,000 100 86 ND ND Vinyl chloride ND ND . ND ND ND ND ND ND pg/L - Micrograms per liter. J - Estimated result, result is less than the RL. ND - Not detected, result is below reporting limit (RL). Samples analyzed for 49 volatile organic compounds (VOCs) by Method 8260B. . PWR - Partially weathered rock Compounds listed in this table are the VOCs reported above the RL in any sample reported during the RCRA Facility Investigation or subsequent testing. Table 9: 12 Month Groundwater Recovery Data Summary April 2016 Semiannual Event Corrective Action Monitoring Report Former Clifton Precision Site Murphy, North Carolina Recovery Well TotalMonthNear �. .. RW-3 RW-4 Operated.. .. TDas . .. May 133,853 29 3 02 5/16115-5/17/15 - System shutdown due to ground g41,979 29 20.16 5/16/15-5117/15 -System shutdown due to ground 2015 fault maintenance work. fault maintenance work. June 2015 116,593 25 3.24 764,728 25 21.24 July 2015 106,356 31 2.38 976,924 31 21.88 August 2015 102,492 31 2.30 994,553 31 22.28 September 2015 101,564 30 2.35 869,344 30 1 20.12 October 2015 93,424 29 2.24 10/5/15-10/6/15 - System shutdown due to severe 1,102,663 29 26.40 10/5/15-10/6/15 - System shutdown due to severe weather weather November 2015 82,002 30 1.90 1,153,716 30 26.71 1219/15-12/10115 - System shutdown due to faulty December 2015 34,390 20 1.19 sensor alarm 1,150,400 29 27.55 12/g/15-12/10/15 - System shutdown due to faulty 12/23/15 - RW-3 Shutdown due to mud and silt sensor alarm accumulation January 2016 0 0 0.00 1,158,212 31 25.95 February 68,348 4.31 2/19/15 - RW-3 returned to service after 1,124,714 26.93 2016 11 development and clean -out 29 3/8116 - RW-3 Turned off due to electrial relay March 2016 98,082 21 3.24 issue 1,174,555 31 26.31 3118/16 - RW-3 Electrical relay issue fixed, retumed to service April 2016 95,491 30 2.21 1,111,503 30 25.73 May 24,744 29 0.59 5/16/15-5/17/15 - System shutdown due to ground 2015 fault maintenance work. June 2015 19,275 21 0.64 July 2015 24,510 19 0.55 August 2015 49,941 31 1.12 September 2015 88,742 30 2.05 10/5115-10/6/15 - System shutdown due to severe October 2015 88,459 29 2.12 weather 10/9115 - RW-4.Transducer Replaced November 2015 101,119 30 2.34 December 90,403 2.16 12/9115-12110115 - System shutdown due to faulty 2015 29 sensor alarm January 2016 86,608 31 1.94 February 2016 70,091 29 1.68 March 2016 112,442 31 2.52 April 2016 145,513 30. 3.37 gpm - gallons per minute /V'oRT/r1ROP VRry WAVAJ ' TRANSMITTAL. Date: 4 May 2017 To: Andrew Moore, P.G. Groundwater Protection Branch Water Quality Regional Operations Section Water Quality Regional Operations Section NCDEQ — Division of Water Resources 1636 Mail Service Center 2090 U.S. Hwy. 70 Raleigh, NC 27699-1636 Swannanoa, NC 28778 cc: Rob McDaniel NCDEQ . HazardousWasteSection 1646 Mail Service Center Raleigh, NC 27699-1646 Meri Scappatura Moog Inc. Corporate -Environmental Engineering Seneca & Jamison Rd ,. East Aurora, NY 14052 John Johnston U.S. Environmental Protection Agency Atlanta Federal Center 61 Forsyth Street, SW Atlanta, GA 30303-8960 Kurt Batsel, P.E. The Dextra Group, Inc. 1205 Johnson Ferry Road, Suite 136-446 Marietta, GA 30068- From: Michael D. Shannon Phone: 310-332-5915 Northrop Grumman Corporation Email: Michael. Shannon@ngo.com on behalf of Northrop Grumman Guidance and Electronics Company, Inc. 101. Continental Boulevard MS: D 12/XE6D21 El Segundo, CA 90245 Subject/Title: 2017 Annual Report for Groundwater Remediation Permit Number WQ0036881 Former Clifton Precision Site, Murphy, NC We are sendingyou the above referenced document(s): - XX For your review and comment. Divisiion, t W�atl R8 ources For your information and file. For your approval 2011 For your signature MAY - 5 Total number of copies sent: 0 Water Quality Regional Operations Asheville Re Tonal Office Remarks: Please find enclosed the 2017 Annual Report for Groundwater Remediation Permit Number WQ0036881 for the: former Clifton Precision Site in Murphy, NC. Please contact Kurt Batsel of The Dextra Group at.770.578.9696- if you have any questions regarding this report. v