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Home My WebLink AboutNC0004987_04_MSS_CAP Update 2019_Tables_20191231Corrective Action Plan Update December 2019 Marshall Steam Station TABLES (CAP Content Section 9) SynTerra Corrective Action Plan Update December 2019 Marshall Steam Station SynTerra Table ES-1 Summary of MSS Assessment Documentation Included in Executive Summary text Corrective Action Plan Update December 2019 Marshall Steam Station SynTerra Table ES-2 Summary of MSS Assessment Activities Included in Executive Summary text Corrective Action Plan Update December 2019 Marshall Steam Station SynTerra Table ES-3 Components of Source Control, Active Remediation, and Monitoring Included in Executive Summary text TABLE 1-1 SUMMARY OF ONSITE INCIDENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Proximity Station Station DEQ Incident Occurrence Closure Release Status Latitude Longitude to Ash Notes Name Location Section Number Date Date Type Basin (ft) Marshall Terrell UST 8601 4/19/1988 Closed 6/20/1989 Petroleum 35.598644 -80.971614 888 NA Marshall Terrell AST 86354 NS Open NA Petroleum 35.599043 -80.966393 1,345 NA Marshall Terrell AST 91147 4/1/2011 Closed 6/15/2011 Petroleum 35.597493 -80.964849 2,036 Incident Name: Booster Fans Marshall Terrell AST 91344 5/5/2015 Open NA Petroleum 35.599831 -80.964106 1,330 Incident Name: Diesel Spill Notes• Onsite incident records provided by Duke Energy AST - Above Ground Storage Tank DEQ - Department of Environmental Quality ft - feet UST - Underground Storage Tank NA - Not Available NS - Not Stated Prepared By: ECW Checked By: WCG Page 1 of 1 TABLE 3-1 SUMMARY OF ONSITE FACILITIES CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Evaluated Facility as Source CSA Operational Area or Name Area n Schedule Status Source Material Capacity Rationale for Evaluation CAP Update Coal Ash/NPDES Ash Basin Yes NA Active Permitted waste 14,033,000 cy CAMA-regulated unit streams Dry Ash Landfill Yes NA Inactive Fly Ash 522,000 cy Regulated via DWM; Adjacent to ash basin (Phase I) Dry Ash Landfill Yes NA Inactive Fly Ash 4,064,000 cy Regulated via DWM; adjacent to ash basin (Phase II) Photovoltaic Coal ash structural fill; adjacent to Structural Yes NA Inactive Coal Ash 5,410,000 cy ash basin Landfill ILF sub- Coal ash structural fill; adjacent to grade Yes NA Inactive Coal Ash 726,000 cy ash basin Structural Fill Access Road Yes NA Inactive Fly Ash 127,982 cy Coal ash structural fill; adjacent to Structural Fill ash basin Coal Pile Yes Dec-19 Active Coal 34 acres Identified as additional source by NCDEQ Gypsum Yes Dec-19 Active Gypsum 4 acres Identified as additional source by Storage Pad NCDEQ Prepared by: WCG Checked by: ECW Notes CSA Schedule - applicable only for units identified in the letter "Final Comprehensive Site Assessment and Corrective Action Plans Approvals for Duke Energy Coal Ash Facilities (April 5, 2019) CAMA - North Carolina Coal Ash Management Act of 2014 CAP - Corrective Action Plan CSA - Comprehensive Site Assessment cy - cubic yards DWM - Division of Waste Management ILF - Industrial Landfill No. 1 NA - not applicable NCDEQ - North Carolina Department of Environmental Quality NPDES - National Pollutant Discharge Elimination System Page 1 of 1 TABLE 4-1 BACKGROUND SOIL SAMPLE SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Soil Boring Depth Range (feet bgs) Number of Sampled Intervals BG-3D ( 1- 12) 2 GWA-2DA (3 - 10) 2 GWA-4D (52 - 53) 1 GWA-5D (27.5 - 29) 1 GWA-14S (3 - 10) 2 BGSB-GWA-02 (2 - 20) 4 BGSB-GWA-04 (2 - 20) 5 BGSB-GWA-06 (2 - 20) 5 Note: ft bgs - feet below ground surface Prepared by: BDW Checked by: ECW Page 1 of 1 TABLE 4-2 BACKGROUND VALUES FOR SOIL CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Reporting Unit PSRG Protection of Groundwater 2018 Background 1 Threshold Values 2019 Updated Background Threshold 2 Values Piedmont Background 3 Threshold Value Range pH* S.U. NE 4.7-6.1 4.2-7.5 2.3-9.8 Aluminum mg/kg 110,000 56,437 56,437 25,978 - 81,619 Antimony mg/kg 0.9 0.65 0.64 0.177 - 0.9 Arsenic mg/kg 5.8 4.697 8.237 1.2 - 43.13 Barium mg/kg 580 819 1,063 122.2 - 1,063 Beryllium mg/kg 63 3.9 3.897 1.2 - 4.52 Boron mg/kg 45 8.7 15 14.4 - 56.3 Cadmium mg/kg 3 0.11 0.72 0.03 - 1 Calcium mg/kg NE 1,500 1,660 410 - 8,769 Chloride mg/kg NE 13 293 12 - 423 Chromium mg/kg 3.8 32.8 406 20 - 440 Cobalt mg/kg 0.9 53.1 62.86 27 - 81.68 Copper mg/kg 700 180 120 17.4 - 216 Iron mg/kg 150 78,228 78,228 24,500 - 85,345 Lead mg/kg 270 82.5 95.23 7.5 - 95.23 Magnesium mg/kg NE 32,462 49,637 760 - 51,829 Manganese mg/kg 65 2,872 3,388 370 - 3,388 Mercury mg/kg 1 0.1 0.1 0.04 - 0.113 Molybdenum mg/kg 7.1 3.5 3.5 1.83 - 12 Nickel mg/kg 130 18.6 237 9.2 - 237 Nitrate (as N) mg/kg NE 0.56 29.3 0.25 - 31.2 Nitrate mg/kg NE --- 43.7 40.3 - 48.8 Potassium mg/kg NE 10,698 18,117 427 - 35,600 Selenium mg/kg 2.1 0.81 2.30 1.58 - 6.857 Sodium mg/kg NE 600 730 338 - 1,500 Strontium mg/kg 1,500 31 28.73 7.1 - 200 Sulfate mg/kg 1,438^ 14 437 12 - 437 Thallium mg/kg 0.28 0.48 0.48 0.166 - 2.132 Total Organic Carbon mg/kg NE --- 3,470 742 - 4,960 Vanadium mg/kg 350 132 132 42 - 230.9 Zinc mg/kg 1,200 72.3 80.8 60.5 - 325.5 Prepared by: ECW Checked by: BDW Notes: 2018 background threshold values approved by North Carolina Department of Environmental Quality (NCDEQ) on May 23, 2018. ^ - PSRG Protection of Groundwater value was calculated using the equation presented on Table 6-2. * - Upper and lower threshold values calculated for parameter Background threshold values were calculated using data from background unsaturated soil samples collected May 2015 to March 2017. z - Background threshold values were calculated using data from background unsaturated soil samples collected May 2015 to August 2018. 3 - Piedmont background threshold value ranges include the Duke Energy calculated 20174 and 20195 background threshold values from 10 Duke Energy facilities located in the Piedmont physiographic region (Allen Steam Stations, Belews Creek Steam Stations, Buck Steam Station°, Cape Fear Steam Electric Plant°, Cliffside Steam Stations, Dan River Steam Station°, Marshall Steam Stations, Mayo Steam Electric Plants, Riverbend Steam Station°, and Roxboro Steam Electric Plants). --- - 2018 background threshold value was not calculated for constituent. mg/kg - milligrams per kilogram NE - not established S.U. - standard unit PSRG - Preliminary Soil Remediation Goals Page 1 of 1 TABLE 4-3 BACKGROUND VALUES FOR GROUNDWATER CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Reporting Unit 15A NCAC 02L Standard 2018 Background Threshold Values 2019 Updated Background Threshold 2 Values Piedmont Background 9 Threshold Value Range Shallow Flow Zone Deep Flow Zone Bedrock Flow Zone Shallow Flow Zone Deep Flow Zone Bedrock Flow Zone pH S.U. 6.5 - 8.5 4.6 -6.4 5.7 - 6.9 5.6 - 7.6 3.6 - 6.6 5.5 - 8.1 5.7 - 7.8 3.6 - 9 Alkalinity mg-CaCO3/L NE 63 204 108 69.4 145 110 19 - 379 Aluminum pg/L NE 757 128 300 1205 180 531.3 100 - 1,238 Antimony pg/L 1* 0.5 0.5 0.5 0.79 0.62 1.0 0.5 - 2.9 Arsenic pg/L 10 0.4 0.6 0.6 1.0 1.4 1.1 0.2 - 6.35 Barium Ng/L 700 310 127 435 580 138 840 10.52-840 Beryllium pg/L 4* 0.2 0.1 0.2 0.223 0.2 1 0.0625 - 1 Bicarbonate mg-CaCO3/L NE 63 204 108 71.4 145 110 19 - 388 Boron pg/L 700 50 50 50 50 50 50 50-176.8 Cadmium Ng/L 2 0.08 0.08 0.08 1 0.08 1 0.08- 1 Calcium mg/L NE 11 13 15 10.7 32.7 18.8 4 - 111 Carbonate mg-CaCO3/L NE 5 5 5 5 5 5 5- 10 Chloride mg/L 250 5.5 4.7 4.5 5.0 4.2 3.6 3.34 - 250 Chromium pg/L 10 16.5 7.6 8.3 16.8 4.3 11.2 1 - 26 Chromium (VI) pg/L NE 5.7 3.0 3.9 7.0 6.0 8.1 0.03 - 12 Cobalt Ng/L 1* 1.2 1.9 2.8 5.0 3.2 2.6 0.088 - 88.85 Copper pg/L 1,000 3.8 2.8 4.2 5.0 10.15 3.356 0.5 - 17.15 Fluoride mg/L 2 --- --- --- 0.51 0.325 1.8 0.1- 1.8 Iron pg/L 300 744 272 792 1,095 225 1,220 56.3-37,500 Lead Ng/L 15 0.3 0.1 0.2 0.447 0.28 1.0 0-2 Lithium pg/L NE --- --- 4.8 10.0 11.4 2 - 95.39 Magnesium mg/L NE 2 14 13 9.98 7.68 14.8 1 - 45 Manganese pg/L 50 75.3 141 26.6 155 142 330 7-9,170 Mercury pg/L 1 0.2 0.2 0.2 0.2 0.2 0.2 0.05 -0.5 Methane pg/L NE 10 10 10 10 10 16.4 1 - 2,505 Molybdenum pg/L NE 0.5 3.2 3.0 1.0 7.3 3.7 0.5 - 26.2 Nickel pg/L 100 9.9 7.5 7.2 19.6 7.8 8.0 0.87 - 48 Nitrate + Nitrite mg-N/L NE 3 1 0.4 6.3 1.6 0.56 0.02 - 6.3 Potassium mg/L NE 5 8 1 5.0 5.27 9.57 1.609 - 18.8 Selenium Ng/L 20 0.5 0.5 0.5 1.0 2.4 1.0 0.5 - 2.4 Sodium mg/L NE 9 29 14 8.69 28.3 16.0 6 - 190 Strontium Ng/L NE 303 665 253 210 727 313 27 - 2,120 Sulfate mg/L 250 4.2 17.7 18.4 11.3 24.2 22.1 1.2 - 510 Sulfide mg/L NE 0.1 0.1 0.1 0.1 0.1 0.1 0.1-2 TDS mg/L 500 140 183 216 152.4 200 195 50-1,200 Thallium Ng/L 0.2* 0.1 0.1 0.1 0.2 0.1 0.2 0.1 -0.2 TOC mg/L NE 1.0 1.0 1.0 2.9 4.8 1.7 1 - 12.3 Total Radium pCi/L 5A 3.0 2.8 5.7 5.33 7.46 6.43 0.494 - 35 Total Uranium pg/ml- 0.03A 0.0005 0.0005 0.0005 0.0005 0.0006 0.0005 0.0002 - 0.864 Page 1 of 2 TABLE 4-3 BACKGROUND VALUES FOR GROUNDWATER CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC 2019 2018 Updated Background Threshold Piedmont 15A NCAC Background Threshold Values 2 Reporting Values Background 9 Constituent Unit 02L Standard Threshold Value Shallow Deep Bedrock Shallow Deep Bedrock Flow Flow Flow Flow Flow Flow Range Zone Zone Zone Zone Zone Zone Vanadium Ng/L 0.3* 5.6 3.8 16.0 13.0 3.9 25.8 0.33 - 25.8 Zinc ug/L 1,000 1 19.2 1 17.0 1 11.9 31.8 29.9 21.0 1 5 - 140 Prepared by: JHG Checked by: HES / BDW Notes: ' - BTVs were calculated using data from background groundwater samples collected September 2015 to October 2017 z Updated BTVs were calculated using data from background groundwater samples collected February 2010 to December 2018 ' - Piedmont background threshold value ranges include the Duke Energy calculated 20174 and 20195 background threshold values from 10 Duke Energy facilities located in the Piedmont physiographic region (Allen Steam Stations, Belews Creek Steam Stations, Buck Steam Station4, Cape Fear Steam Electric Plant4, Cliffside Steam Stations, Dan River Steam Station4, Marshall Steam Stations, Mayo Steam Electric Plants, Riverbend Steam Station 4, and Roxboro Steam Electric Plants). Background threshold values (BTVs) have been rounded to similar levels of precision as 15A North Carolina Administrative Code (NCAC) 02L Standard or Interim Maximum Allowable Concentration (IMAC). - BTV was not calculated for constituent. * - IMAC of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. A - Federal Maximum Contaminant Level pg/L - micrograms per liter pg/mL - micrograms per milliliter mg/L - milligrams per liter mg-CaCO3/L - milligrams calcium carbonate per liter mg-N/L - milligrams nitrogen per liter NE - not established pCi/L - picocuries per liter S.U. - standard units TDS - total dissolved solids TOC - total organic carbon Page 2 of 2 TABLE 4-4 BACKGROUND DATASET RANGES FOR SURFACE WATER CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Reporting Unit Comparison Criteria Background Range Constituents with 15A NCAC 02B Class 6 Water Supply: WS-IV 1 Standards pH S.U. 6.0-9.0 6.1 - 7.7 Dissolved Oxygen mg/L >_ 4 1.17 - 9.30 Temperature deg C < 32 10 - 33 Turbidity NTU <_ 25 1.2 - 46.9 Arsenic pg/L 10 0.071 j - 1.4 Arsenic (Dissolved) pg/L acute: 340 chronic: 150 0.042 j - 0.92 Barium pg/L 1000 9.7 - 60 Beryllium (Dissolved) pg/L acute: 65, chronic: 6.5 <0.1 Cadmium Dissolved 2 pg/L acute: 0.82, chronic: 0.15 <0.08 Chloride mg/L 230 1.9 - 12 Chromium III Dissolved 2,3 pg/L acute: 180, chronic: 24 0.36 - 4.62 Chromium (VI) (Dissolved) pg/L acute: 16, chronic: 11 <0.025 - 2.1 Copper Dissolved 2 pg/L acute: 3.6, chronic: 2.7 <0.5 - 4.6 Fluoride mg/L 1.8 <0.1 Lead Dissolved 2 pg/L acute: 14, chronic: 0.54 <0.1 - 0.32 Mercury pg/L chronic: 0.012 0.000514 - 0.00685 Nickel pg/L 25 <0.5 - 5 Nickel Dissolved 2 pg/L acute:140, chronic: 16 <0.5 - 4.6 Nitrate + Nitrite mg-N/L 10 <0.02 - 0.82 Selenium pg/L chronic: 5 <0.5 Silver Dissolved 2 pg/L acute: 0.3, chronic: 0.06 <0.5 Sulfate m /L 250 <1 - 31.7 Thallium pg/L 2 0.015 - 0.12 Total Dissolved Solids m /L 500 <25 - 5680 Total Hardness mg/L 100 11.8 - 28.8 Zinc Dissolved 2 pg/L acute: 36, chronic: 36 <10 - 24.9 Constituents with USEPA National Recommended Water Quality Criteria Alkalinity m /L chronic: 20 10.8 - 33.9 Aluminum pg/L acute: 620, chronic: 300 <100 - 1830 Antimony pg/L 5.6 <0.5 Iron pg/L 1000 88.9 - 4,100 Manganese pg/L 50 13.1 j - 674 Constituents without 02B or USEPA Criteria Bicarbonate mg-CaCO3/1- NE 10.8 - 33.9 Boron pg/L NE 27.8 j - 520 Cadmium pg/L NE <0.08 Calcium mg/L NE 2.34 - 11.6 Carbonate Alkalinity mg-CaCO3/1- NE <5 Chromium pg/L NE <0.5 - 2 B Chromium (VI) pg/L NE <0.025 - 2.1 Cobalt pg/L NE 0.061 - 3.5 Copper pg/L NE 0.16 j - 2.9 Lead pg/L NE <0.1 - 1 Lithium pg/L NE 0.67 B - 1.3 Magnesium mg/L NE 0.859 - 4.89 Methane pg/L NE 4.9 j+ - 159 Molybdenum /L NE 0.11 j - <0.5 Page 1 of 2 TABLE 4-4 BACKGROUND DATASET RANGES FOR SURFACE WATER CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Reporting Unit Comparison Criteria Background Range Potassium mg/L NE 2.93 j - <5 Sodium mg/L NE 3.06 j - 8.69 Strontium dig/L NE 22.3 - 130 Sulfide mg/L NE <0.1 Total Organic Carbon mg/L NE 0.74 j - 7.1 Total Radium pCi/L NE NA Total Uranium pg/mL NE NA Vanadium fag/L NE 0.27 j - 3.7 Zinc /L NE 2.6 ' - 83.4 Prepared by: ECW Checked by: PPB Notes: Background locations, which were part of the evaluation of potential groundwater to surface water impacts, were approved by North Carolina Department of Environmental Quality (NCDEQ). All samples collected from Lake Norman and its tributaries are subject to Class B, WS-IV water quality standards. 1 15A NCAC 02B .0101(c)(6) Class WS-IV - Waters protected as water supplies which are generally in moderately to high developed watersheds. Suitable for all Class C uses. Z Standard value dependent on hardness. Calculated hardness dependent metal standards represent most conservative value. Standards are calculated using 25 mg/L hardness, regardless if actual instream hardness values are greater than 25 mg/L. 3 Chromium speciation is not performed for trivalent chromium (Cr(III)). Trivalent values are derived by subtracting hexavalent chromium values from dissolved chromium values. Where a dissolved chromium value is less than the detection limit ("<"), it is considered a whole number for purposes of deriving a trivalent chromium value. Acute - "Compliance with acute instream metals standards shall only be evaluated using an average of two or more samples collected with one hour." Reference 15A NCAC 02B .0211 Chronic - "Compliance with chronic instream metals standards shall only be evaluated using averages of a minimum of four samples taken on consecutive days, or as a 96-hour average" Reference 15A NCAC 02B .0211. NTU - Nephelometric Turbidity Unit deg C - degrees Celcius < - less than mg/L - milligrams per liter pg/L - micrograms per liter pg/mL - micrograms per milliliter mg-CaCO3/L - milligrams calcium carbonate per liter mg-N/L - milligram nitrogen per liter NA - not available NE - not established pCi/L - picocuries per liter S.U. - standard unit B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 10X the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j- - Estimated concentration, biased low. j+ - Estimated concentration, biased high. Page 2 of 2 TABLE 4-5 BACKGROUND DATASET RANGES FOR SEDIMENT CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Reporting Unit Background Range pH S.U. 5.2 - 6.7 Aluminum mg/kg 3,100 - 20,000 Antimony mg/kg <0.54 - <0.74 Arsenic mg/kg 0.29 j - 1.4 Barium mg/kg 4 - 74 Beryllium mg/kg 0.055 j - 0.67 Boron mg/kg 1.3 j - <3.2 Cadmium mg/kg <0.14 - <0.19 Calcium mg/kg 42 j - 1,600 Chloride mg/kg 3.4 j - <14 Chromium mg/kg 0.68 -14 Chromium (III) mg/kg NE Cobalt mg/kg <0.89 - 4.2 Copper mg/kg 0.3 j - 15 Iron mg/kg 710 M - 15,000 Lead mg/kg 1.1 - 16 Magnesium mg/kg 60 j,M - 3,800 Manganese mg/kg 10 M - 230 Mercury mg/kg 0.032 j - <0.099 Molybdenum mg/kg <2 - <2.5 Nickel mg/kg 0.81 j - 4.8 Nitrate (as N) mg/kg <0.24 - <0.32 Nitrate mg/kg NE Potassium mg/kg 110 j - 4,100 Selenium mg/kg <1.4 - <1.9 Silver mg/kg <0.5 - <0.64 Sodium mg/kg 37 j - 96 j Strontium mg/kg 0.62 j - 17 Sulfate mg/kg <12 - <16 Sulfide mg/kg 19.2 j - <33.1 Thallium mg/kg 0.054 j - 0.26 Total Organic Carbon mg/kg 4,170 - 58,200 Vanadium mg/kg 3.9 - 38 Zinc mg/kg 1.7 j - 33 Prepared by: ECW Checked by: KHG Notes: Background locations, including SW-7, SW-8, SW-105, SW-106, which were part of the evaluation of potential groundwater to surface water impacts, were approved by North Carolina Department of Environmental Quality (NCDEQ). < - Concentration not detected at or above the adjusted reporting limit. j - estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. M - Matrix spike / matrix spike duplicate failure. mg/kg - milligrams per kilogram NE - not established S.U. - standard unit Page 1 of 1 TABLE 5-1 MAY 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) May 2019Measured Water Level' (ft. BTOC) May 2019 Water Elevation (ft. NAVD 88) Monitoring Flow Zone AB-01BR 777.21 655.83 650.83 0.02 777.19 Bedrock AB-01BRL2 776.78 615.77 610.77 -0.27 777.05 Bedrock AB-01BRLL2 776.54 581.54 571.54 -0.55 777.09 Bedrock AB-01BRLLL2 777.70 374.45 364.45 -0.27 1777.97 Bedrock AB-01D 777.09 683.69 678.69 3.16 773.93 Deep AB-01S 777.27 769.06 754.06 6.02 771.25 Shallow AB-02BR2 781.06 488.13 478.13 0.00 781.06 Bedrock AB-02D 781.44 687.48 682.48 13.11 768.33 Deep AB-02S 781.30 761.58 746.58 18.49 762.81 Shallow AB-03D 815.03 682.14 677.14 21.96 793.07 Bedrock AB-03S 815.08 804.00 789.00 23.50 791.58 Shallow AB-04D 810.01 735.67 730.67 19.04 790.97 Deep AB-04S 809.73 801.43 786.43 16.19 793.54 Shallow AB-04SL 809.85 768.84 758.84 16.74 793.11 Shallow AB-05BR 807.55 699.45 694.45 13.01 794.54 Bedrock AB-05D 807.52 726.47 721.47 12.74 794.78 Deep AB-05DU 807.58 749.92 739.92 12.65 794.93 Shallow AB-05S 807.50 801.36 786.36 12.52 794.98 Shallow AB-06BRA 836.70 733.77 731.70 11.30 825.40 Bedrock AB-06BRL 836.76 679.14 674.14 12.80 823.96 Bedrock AB-06D 835.36 770.40 765.40 9.42 825.94 Bedrock AB-06S 835.38 825.77 810.77 7.70 827.68 Shallow AB-07D 834.13 752.21 747.21 12.46 821.67 Deep AB-07DU 834.08 786.62 776.62 12.40 821.68 Shallow AB-07S 834.29 826.43 811.43 10.95 823.34 Shallow AB-08D 800.50 702.50 697.50 7.33 793.17 Bedrock AB-08DU 800.38 747.53 737.53 7.19 793.19 Shallow AB-08S 800.33 794.42 784.42 7.42 792.91 Shallow AB-09BR 797.64 716.94 711.94 6.61 791.03 Bedrock AB-09D 797.26 746.76 741.76 6.88 790.38 Bedrock AB-09S 797.78 792.38 782.38 6.50 791.28 Shallow AB-10BR 802.54 679.53 674.53 11.04 791.50 Bedrock AB-10BRL 801.59 549.35 539.35 5.59 796.00 Bedrock AB-10D 802.68 728.58 723.58 11.56 791.12 Bedrock AB-10S 802.41 790.54 775.54 9.81 792.60 Shallow AB-10SL 802.52 759.52 749.52 10.97 791.55 Shallow AB-11D 799.95 719.84 714.84 0.50 799.45 Bedrock AB-11S 800.05 790.89 780.89 3.65 796.40 Shallow AB-12BR2 797.43 694.09 689.09 -0.65 798.08 Bedrock AB-12D 795.45 730.56 725.56 3.22 792.23 Bedrock AB-12S 795.61 789.70 779.70 4.90 790.71 Shallow AB-12SL 795.67 752.70 742.70 4.54 791.13 Shallow AB-13D 824.55 740.59 735.59 24.57 799.98 Bedrock AB-13S 823.73 806.41 791.41 21.23 802.50 Shallow AB-14D 824.11 741.45 736.45 8.25 815.86 Deep Page 1 of 5 TABLE 5-1 MAY 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) May 2019Measured Water Level' (ft. BTOC) May 2019 Water Elevation (ft. NAVD 88) Monitoring Flow Zone AB-14DU 824.83 779.01 769.01 8.91 815.92 Shallow AB-14S 824.71 816.03 801.03 10.01 814.70 Shallow AB-15BR 823.01 713.04 708.04 15.44 807.57 Bedrock AB-15D 823.04 756.26 751.26 19.12 803.92 Bedrock AB-15S 823.27 815.14 800.14 17.96 805.31 Shallow AB-15SL 823.17 780.02 770.02 21.48 801.69 Shallow AB-16D 822.45 778.50 773.50 5.21 817.24 Bedrock AB-16DU 823.00 802.00 792.00 5.69 817.31 Deep AB-16S 822.08 815.82 805.82 5.02 817.06 Shallow AB-20D 892.35 750.14 745.14 65.90 826.45 Bedrock AB-20S 892.43 835.79 820.79 63.52 828.91 Shallow AB-21D 810.23 747.61 742.61 16.78 793.45 Deep AB-21S 810.66 794.95 779.95 18.70 791.96 Shallow AL-01BR 818.07 693.02 688.02 40.11 777.96 Bedrock AL-01BRL 815.41 548.29 538.29 35.41 780.00 Bedrock AL-01D 817.94 735.45 730.45 42.25 775.69 Deep AL-01S 817.97 783.43 768.43 37.06 780.91 Shallow AL-02BR 915.10 709.18 704.18 111.27 803.83 Bedrock AL-02BRL 915.39 658.09 653.09 115.10 800.29 Bedrock AL-02BRLL 914.63 571.77 566.77 115.61 799.02 Bedrock AL-02BRLLL 915.81 433.00 423.00 116.71 799.10 Bedrock AL-02D 915.33 760.83 755.83 112.93 802.40 Deep AL-02S 915.41 800.83 785.83 114.20 801.21 Shallow AL-03BR 919.02 687.53 682.53 113.57 805.45 Bedrock AL-03D 918.69 737.49 732.49 111.36 807.33 Deep AL-03S 918.59 818.97 798.17 110.15 808.44 Shallow AL-04BR 918.72 736.75 731.75 108.03 810.69 Bedrock AL-04BRL 918.74 665.85 655.85 119.58 799.16 Bedrock AL-04D 918.44 767.61 762.61 105.04 813.40 Deep BG-01BRA 817.24 730.23 728.24 12.59 804.65 Bedrock BG-01D 817.63 779.75 774.75 7.57 810.06 Deep BG-01S 817.35 807.29 797.29 7.30 810.05 Shallow BG-02BR 814.81 761.99 756.99 4.62 810.19 Bedrock BG-02S 814.33 804.82 794.82 4.64 809.69 Shallow BG-03BR 867.69 759.72 754.72 31.18 836.51 Bedrock BG-03D 864.18 802.56 797.56 21.75 842.43 Deep BG-03S 863.03 838.55 828.55 22.74 840.29 Shallow CCR-01D 809.32 723.43 718.43 12.90 796.42 Deep CCR-01S 810.31 787.40 772.40 11.12 799.19 Shallow CCR-02D 806.89 729.93 724.93 14.67 792.22 Deep CCR-02S 806.56 786.81 771.81 14.44 792.12 Shallow CCR-03D 1780.44 684.08 1679.08 20.44 760.00 Deep CCR-03S 780.28 759.05 744.05 20.93 759.35 Shallow CCR-04D 783.82 683.57 678.57 21.39 762.43 Deep CCR-04S 783.66 1 763.42 748.42 22.28 761.38 Shallow Page 2 of 5 TABLE 5-1 MAY 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) May 2019Measured Water Level' (ft. BTOC) May 2019 Water Elevation (ft. NAVD 88) Monitoring Flow Zone CCR-05D 776.97 696.83 691.83 13.78 763.19 Deep CCR-05S 777.25 758.91 743.91 14.81 762.44 Shallow CCR-09DA 799.77 685.67 680.67 28.72 771.05 Deep CCR-09S 799.88 769.68 754.68 32.20 767.68 Shallow CCR-11D 793.86 718.99 713.99 6.08 787.78 Deep CCR-11S 794.24 786.43 771.43 6.63 787.61 Shallow CCR-12D 793.84 709.18 704.18 5.46 788.38 Deep CCR-12S 793.85 785.45 770.45 5.48 788.37 Shallow CCR-13D 800.02 720.15 715.15 12.41 787.61 Deep CCR-13S 799.68 740.57 725.57 12.14 787.54 Shallow CCR-14D 796.11 736.52 731.52 8.15 787.96 Deep CCR-14S 795.97 788.75 773.75 8.04 787.93 Shallow CCR-15D 805.14 748.91 743.91 10.39 794.75 Deep CCR-15S 804.76 798.25 783.25 10.12 794.64 Shallow CCR-16D 819.37 772.92 767.92 20.45 798.92 Deep CCR-16S 819.32 810.62 795.62 13.13 806.19 Shallow CP-ID 806.40 744.66 734.66 14.62 791.78 Deep CP-1S 806.32 793.47 783.47 14.27 792.05 Shallow CP-2D 810.83 710.95 700.95 10.80 800.03 Deep CP-2S 810.67 788.79 778.79 10.57 1 800.10 Shallow CP-3D 810.58 738.69 728.69 13.52 797.06 Deep CP-3S 810.47 794.81 784.81 14.12 796.35 Shallow GP-1D 858.03 756.00 746.00 55.94 802.09 Deep GP-1S 858.13 806.13 796.13 56.03 802.10 Shallow GP-2D 833.68 731.73 721.73 28.50 805.18 Deep GP-2S 833.45 805.52 795.52 27.73 805.72 Shallow GP-3D 856.46 745.53 735.53 51.05 805.41 Deep GP-3S 856.39 804.46 794.46 50.98 805.41 Shallow GWA-01BR 806.10 651.65 646.65 40.27 765.83 Bedrock GWA-01D 806.05 684.27 679.27 42.60 763.45 Deep GWA-01S 805.97 765.16 750.16 43.40 762.57 Shallow GWA-02DA 826.59 729.79 724.79 20.34 806.25 Deep GWA-02S 826.97 813.47 794.41 20.05 806.92 Shallow GWA-03D 839.44 800.48 795.48 3.54 835.90 Deep GWA-03S 839.24 833.42 823.42 2.76 836.48 Shallow GWA-04D 902.45 818.38 813.38 53.34 849.11 Deep GWA-04S 901.97 849.78 834.78 53.92 848.05 Shallow GWA-05D 847.17 800.86 795.86 33.66 813.51 Deep GWA-06D 845.72 741.32 736.32 38.42 807.30 Bedrock GWA-06S 845.37 805.29 795.29 37.96 807.41 Shallow GWA-07D 812.50 784.05 779.05 5.59 806.91 Deep GWA-07S 810.72 798.80 788.80 7.12 803.60 Shallow GWA-08D 853.68 794.59 789.59 29.64 824.04 Bedrock GWA-08S 852.90 826.75 811.75 28.25 824.65 Shallow GWA-09BR2 850.45 763.53 758.53 -2.00 852.45 Bedrock Page 3 of 5 TABLE 5-1 MAY 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) May 2019Measured Water Level' (ft. BTOC) May 2019 Water Elevation (ft. NAVD 88) Monitoring Flow Zone GWA-10D 778.10 661.77 657.27 9.38 768.72 Deep GWA-10S 777.65 770.32 755.32 11.59 766.06 Shallow GWA-11BR 810.03 657.00 652.00 44.81 765.22 Bedrock GWA-11D 811.24 698.44 693.44 45.80 1765.44 Deep GWA-11S 812.55 769.79 754.79 44.94 767.61 Shallow GWA-12BR 875.65 763.02 758.02 10.10 865.55 Bedrock GWA-12D 875.83 788.29 783.29 9.34 866.49 Bedrock GWA-12S 887.87 878.41 863.41 10.50 877.37 Shallow GWA-13DA 888.28 736.14 731.28 19.42 868.86 Deep GWA-13S 887.87 873.51 858.51 10.52 877.35 Shallow GWA-14D 911.41 806.98 801.98 38.32 873.09 Deep GWA-14S 910.69 876.24 861.24 37.72 872.97 Shallow GWA-15D 781.85 719.96 709.96 23.00 758.85 Deep GWA-15S 781.39 757.73 742.73 22.69 758.70 Shallow ILF-1BR 865.61 765.78 755.78 38.52 827.09 Bedrock ILF-1D 865.32 792.59 782.59 38.28 827.04 Deep ILF-1S 865.31 822.47 812.47 37.35 827.96 Shallow ILF-2D 885.14 793.57 783.57 44.38 840.76 Deep ILF-2S 884.79 843.21 833.21 47.09 837.7 Shallow MS-08 872.34 849.35 839.35 41.95 830.39 Shallow MS-09 868.04 825.36 815.36 38.92 829.12 Shallow MS-10 851.29 834.95 824.95 15.34 835.95 Shallow MS-11 859.78 824.15 814.15 31.20 828.58 Shallow MS-12 835.66 811.61 801.61 20.14 815.52 Shallow MS-13 841.90 807.67 797.67 28.57 813.33 Shallow MS-14 844.07 806.89 796.89 32.36 811.71 Shallow MS-15 861.47 805.34 795.34 38.23 823.24 Shallow MS-16 836.98 806.79 796.79 23.60 813.38 Deep MW-01 823.70 754.10 744.10 49.86 773.84 Shallow MW-02 797.21 771.90 761.90 6.04 791.17 Shallow MW-03 813.07 795.10 785.10 8.02 805.05 Shallow MW-04 866.42 823.55 813.55 35.56 830.86 Shallow MW-04D 866.74 807.87 802.87 35.68 831.06 Bedrock MW-05 822.69 802.19 792.19 23.54 799.15 Shallow MW-06D 791.19 705.62 700.62 17.30 773.89 Deep MW-06S 790.35 772.58 762.58 18.71 771.64 Shallow MW-07D 776.85 711.46 706.46 6.25 770.60 Deep MW-07S 775.99 762.50 752.50 12.87 763.12 Shallow MW-08D 775.18 678.64 673.64 13.79 761.39 Bedrock MW-08S 775.34 754.42 744.42 15.78 759.56 Shallow MW-09D 777.38 684.14 679.14 16.72 760.66 Deep MW-09S 777.34 753.44 743.44 14.48 762.86 Shallow MW-10D 772.04 687.53 682.53 13.87 758.17 Deep MW-10S 772.05 755.53 740.53 14.12 757.93 Shallow MW-11D 884.67 793.85 788.85 40.89 843.78 Deep Page 4of5 TABLE 5-1 MAY 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) May 2019Measured Water Level' (ft. BTOC) May 2019 Water Elevation (ft. NAVD 88) Monitoring Flow Zone MW-11S 884.99 842.89 827.89 41.14 843.85 Shallow MW-12D 871.88 775.71 770.71 12.98 858.90 Deep MW-12S 871.86 858.92 843.92 11.10 1 860.76 Shallow MW-13DZ 847.05 800.89 795.89 0.00 847.05 Deep MW-13S 847.49 839.02 824.02 2.15 845.34 Shallow MW-14BR 810.49 708.65 703.65 33.76 776.73 Bedrock MW-14BRL 811.77 521.05 511.05 28.45 783.32 Bedrock MW-14D 811.43 751.07 746.07 35.13 776.30 Deep MW-14S 811.29 776.36 761.36 34.52 776.77 Shallow MW-PZ1 851.30 819.70 809.70 33.78 817.52 Shallow MW-PZ10 851.26 816.90 806.90 29.91 821.35 Shallow MW-PZ2 836.62 828.70 818.70 17.73 818.89 Shallow MW-PZ3 845.54 813.90 803.90 36.16 809.38 Shallow MW-PZ4 832.64 815.20 805.20 22.87 809.77 Shallow MW-PZ5 833.68 821.40 806.40 25.50 808.18 Shallow MW-PZ6 845.33 815.10 805.10 36.56 808.77 Shallow MW-PZ7 808.02 803.60 783.60 5.04 802.98 Shallow MW-PZ8 849.70 830.10 820.10 Dry -- Shallow MW-PZ9 846.77 827.10 802.10 40.80 805.97 Shallow OB-01 (Dry Ash Landfill) 825.85 770.40 760.40 44.82 781.03 Shallow OB-1 (Ash Basin) 850.57 807.89 792.09 43.65 806.92 Shallow (MW-6) OB-2 919.65 814.68 799.68 105.90 813.75 Shallow MW-07 (013-3) 859.16 817.56 802.56 43.94 815.22 Shallow PVSF-1BR 880.17 712.36 697.36 53.48 826.69 Bedrock PVSF-1D 880.28 800.55 790.55 52.75 827.53 Deep PVSF-1S 880.27 825.62 815.62 52.46 827.81 Shallow PVSF-2BR 833.36 738.48 723.48 12.13 821.23 Bedrock PVSF-2D 833.20 778.44 768.44 11.62 821.58 Deep PVSF-2S 833.15 818.44 808.44 11.48 821.67 Shallow PVSF-3BR 838.22 657.88 647.88 15.61 822.61 Bedrock PVSF-3D 838.02 698.44 688.44 14.08 823.94 Deep PVSF-3S 838.18 818.17 808.17 17.17 821.01 Shallow PVSF-4BR3 858.45 713.66 703.66 99.95 758.50 Bedrock PVSF-4D3 858.58 788.78 778.78 10.40 848.18 Deep PVSF-4S3 858.57 828.74 818.74 10.03 848.54 Shallow Prepared by: ECW Checked by: BDW Notes: Manual water levels collected on May 20, 2019 Z Artesian conditions present 3 Water Levels measured on August 26, 2019, during the next quarterly sampling event after well installation. ft. BTOC - feet below top of casing ft. NAVD 88 - feet North American Vertical Datum of 1988 See Figures 5-4a through 5-4c for graphical representation of data Page 5 of 5 TABLE 5-2 HORIZONTAL HYDRAULIC GRADIENTS AND FLOW VELOCITIES CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Shallow Flow Zone Upgradient Downgradient Source Area Groundwater Groundwater K Ah Al n 3 vs vs Gradient Level h (ft)t Level h (ft)2 (ft/day)3 (ft) (ft)4 a (ft/day) (ft/yr) (Ah/AI) PV Structural Fill 850 820 1.0 30.00 1800 0.3 0.056 20.28 0.02 Ash Basin 805 765 1.0 40.00 5400 0.3 0.025 9.01 0.01 Dry Ash Landfill Phase II 815 795 1.0 20.00 1600 0.3 0.042 15.21 0.01 Dry Ash Landfill 785 765 1.0 20.00 600 0.3 0.111 40.56 0.03 Phase I Coal Pile 795 765 1.0 30.00 1850 0.3 0.054 19.73 0.02 m G suPad 805 795 1.0 10.00 925 0.3 0.036 13.15 0.01 Shallow Flow Zone Geometric Mean 0.048 17.6 0.01 Average 0.05 19.7 0.02 Deep Flow Zone Upgradient Downgradient Source Area Groundwater Groundwater K Ah AI s na v s v s Gradient Level h (ft)t Level h (ft)2 (ft/day)3 (ft) (ft)4 (ft/day) (ft/yr) (Ah/AI) PV Structural Fill 855 825 1.5 30.00 1550 0.3 0.097 35.32 0.02 Ash Basin 815 770 1.5 45.00 5250 0.3 0.043 15.64 0.01 Dry Ash Landfill Phase II 815 800 1.5 15.00 1600 0.3 0.047 17.11 0.01 Dry Ash Landfill 785 765 1.5 20.00 550 0.3 0.182 66.36 0.04 Phase I Coal Pile 800 765 1.5 35.00 1850 0.3 0.095 34.53 0.02 G sum Pad 1 805 800 1 1.5 5.00 850 1 0.3 1 0.029 10.74 0.01 Deep Flow Zone Geometric Mean 0.068 24.8 0.01 Average 0.08 30.0 0.02 Bedrock Flow Zone Upgradient Downgradient Source Area Groundwater Groundwater K Ah Al 3 ne vs vs Gradient Level h (ft) Level h (ft) (ft/day)3 (ft) (ft)4 (ft/day) (ft/yr) (Ah/AI) PV Structural Fill 850 820 0.7 30.00 1450 0.01 1.448 528.62 0.02 Ash Basin 805 775 0.7 30.00 5200 0.01 0.404 147.40 0.01 Dry Ash Landfill Phase II 810 795 0.7 15.00 1900 0.01 0.553 201.71 0.01 Dry Ash Landfill Ph I 780 770 0.7 10.00 670 0.01 1.045 381.34 0.01 Bedrock Flow Zone Geometric Mean 0.762 278.2 0.01 Average 0.86 314.8 0.01 Notes: Prepared by : GTC Checked by: 3DW ' - Groundwater level shown corresponds to upgradient groundwater contour on Figures 5-4a through 5-4c z - Groundwater level shown corresponds to downgradient groundwater contour on Figures 5-4a through 5-4c 3 - Values taken from Preliminary Updated Groundwater Flow and Transport Modeling Report for Marshall Steam Station, Terrell, INC, November 2018 4 - The length of a flow path between an upgradient and downgradient groundwater contor within the same flow zone ft - feet h - water level height in feet K - horizontal hydraulic conductivity I - horizontal distance between wells ne - effective porosity vs - horizontal seepage velocity Oh - difference in water level height between upgradient and downgradient locations Al - horizontal distance between upgradient and downgradient locations Page 1 of 1 TABLE 5-3 VERTICAL HYDRAULIC GRADIENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Monitoring Zone Reference Cross- Section Total Well Depth',2 (Ft-BGS) Elevation mid - Point of Screened Interval Water Level Elevation 5-20-2019 Vertical Gradient and Flow Direction Dry Ash Landfill (Phase 11) AL-02S Shallow N/A 130.18 793.33 801.21 -0.03 Upward AL-02D Deep 164.50 758.33 802.40 AL-02D Deep N/A 164.50 758.33 802.40 -0.03 Upward AL-02BR Bedrock 230.82 706.68 803.83 AL-02BR Bedrock N/A 230.82 706.68 803.83 0.07 Downward AL-02BRL Bedrock 263.50 655.59 800.289 AL-02BRL Bedrock N/A 263.50 655.59 800.289 0.01 Downward AL-02BRLL Bedrock 345.00 569.27 799.019 AL-02BRLL Bedrock N/A 345.00 569.27 799.02 0.00 AL-02BRLLL Bedrock 490.00 290.45 799.10 AL-02S Shallow N/A 130.18 793.33 801.21 -0.03 Upward AL-02BR Bedrock 230.82 706.68 803.83 AL-02S Shallow N/A 130.18 793.33 801.21 0.01 Downward AL-02BRL Bedrock 263.50 655.59 800.289 AL-02S Shallow N/A 130.18 793.33 801.21 0.01 Downward AL-02BRLL Bedrock 345.00 569.27 799.019 AL-02S Shallow N/A 130.18 793.33 801.21 0.00 AL-02BRLLL Bedrock 490.00 290.45 799.10 AL-03S Ash Pore Water N/A 120.42 808.57 808.44 0.02 Downward AL-03D Deep 189.70 734.99 807.33 AL-03D Deep N/A 189.70 734.99 807.33 0.04 Downward AL-03BR Bedrock 239.30 685.03 805.45 AL-04D Deep N/A 159.83 765.11 813.40 0.03 Downward AL-04BR Bedrock 211.00 660.85 810.69 AL-04BR Bedrock N/A 211.00 660.85 810.685 -0.16 Upward AL-04BRL Bedrock 260.00 734.25 799.161 AB-10S Shallow C-C' 27.87 783.04 792.60 0.04 Downward AB-10SL Shallow 56.00 754.52 791.55 AB-10SL Shallow C-C' 56.00 754.52 791.55 -0.17 Upward AB-10D Deep 84.20 757.02 791.12 AB-10D Deep C-C' 84.20 757.02 791.12 0.00 -- AB-10BR Bedrock 134.00 677.03 791.50 Dry Ash Landfill (Phase 1) AL-01 S Shallow N/A 50.34 775.93 780.91 0.12 Downward AL-01D Deep 92.29 732.95 775.69 Page 1 of 4 TABLE 5-3 VERTICAL HYDRAULIC GRADIENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Monitoring Zone Reference Cross- Section Total Well Depth',2 (Ft-BGS) Elevation mid - Point of Screened Interval Water Level Elevation 5-20-2019 Vertical Gradient and Flow Direction Dry Ash Landfill (Phase 1) (Continued) AL-01 D Deep N/A 92.29 732.95 775.69 -0.05 Upward AL-01BR Bedrock 132.00 690.52 777.96 GWA-11S Shallow N/A 78.96 762.29 767.61 0.03 Downward GWA-11D Deep 129.00 695.94 765.44 GWA-11D Deep N/A 129.00 695.94 765.44 0.01 Downward GWA-11BR Bedrock 155.00 654.50 765.22 Downgradient of Ash Basin Dam AB-01 S Shallow N/A 23.71 761.56 771.25 -0.03 Upward AB-01 D Deep 99.90 681.19 773.93 AB-01 D Deep N/A 99.90 681.19 773.93 -0.12 Upward AB-01 BR Bedrock 134.38 653.33 777.19 AB-01 BR Bedrock N/A 134.38 653.33 777.19 0.05 Downward AB-01 BRL Bedrock 166.00 611.27 775.05 AB-01 BRL Bedrock N/A 166.00 611.27 775.05 0.00 AB-01 BRLL Bedrock 205.00 574.79 775.09 AB-01 BRLL Bedrock N/A 205.00 574.79 775.09 0.00 AB-01 BRLLL Bedrock 413.00 367.45 775.97 AB-01 S Shallow N/A 23.71 761.56 771.25 -0.05 Upward AB-01 BR Bedrock 134.38 653.33 777.19 AB-01 S Shallow N/A 23.71 761.56 771.25 -0.03 Upward AB-01 BRL Bedrock 166.00 611.27 775.05 AB-01 S Shallow N/A 23.71 761.56 771.25 -0.02 Upward AB-01 BRLL Bedrock 205.00 574.79 775.09 AB-01 S Shallow N/A 23.71 761.56 771.25 -0.01 Upward AB-01 BRLLL Bedrock 413.00 367.45 775.97 PV Structural Fill PVSF-1S Shallow N/A 62.00 820.62 827.81 0.01 Downward PVSF-1D Deep 87.00 795.55 827.53 PVSF-1D Deep N/A 87.00 795.55 827.53 0.01 Downward PVSF-1BR Bedrock 180.00 704.86 826.69 PVSF-1S Shallow N/A 62.00 820.62 827.81 0.01 Downward PVSF-1BR Bedrock 180.00 704.86 826.69 PVSF-2S Shallow N/A 22.00 813.44 821.67 0.00 PVSF-2D Deep 62.00 773.44 821.58 Page 2 of 4 TABLE 5-3 VERTICAL HYDRAULIC GRADIENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Monitoring Zone Reference Cross- Section Total Well Depth',2 (Ft-BGS) Elevation mid - Point of Screened Interval Water Level Elevation 5-20-2019 Vertical Gradient and Flow Direction PV Structural Fill (Continued) PVSF-2D Deep N/A 62.00 773.44 821.58 0.01 Downward PVSF-2BR Bedrock 107.00 730.99 821.23 PVSF-2S Shallow N/A 22.00 813.44 821.67 0.01 Downward PVSF-2BR Bedrock 107.00 730.99 821.23 PVSF-3S Shallow N/A 27.00 813.17 821.01 -0.02 Upward PVSF-3D Deep 147.00 693.44 823.94 PVSF-3D Deep N/A 147.00 693.44 823.94 0.03 Downward PVSF-3BR Bedrock 187.50 652.88 822.61 PVSF-3S Shallow N/A 27.00 813.17 821.01 -0.01 Upward PVSF-3BR Bedrock 187.50 652.88 822.61 PVSF-4S Shallow N/A 40.00 823.74 848.54 0.01 Downward PVSF-4D Deep 80.00 783.78 848.18 PVSF-4D Deep N/A 80.00 783.78 848.18 1.19 Downward PVSF-4BR Bedrock 155.00 708.66 758.50 PVSF-4S Shallow N/A 40.00 823.74 848.54 0.78 Downward PVSF-4BR Bedrock 155.00 708.66 758.5 Structural Fill Access Road AB-06S Ash Pore Water C-C' 24.61 818.27 827.68 0.03 Downward AB-06D Bedrock 78.26 767.90 825.94 AB-06D Bedrock C-C' 78.26 767.90 825.94 0.01 Downward AB-06BRA Bedrock 112.93 725.34 825.40 Coal Pile CP-1 S Shallow N/A 20.00 788.47 792.05 0.01 Downward CP-1 D Deep 69.00 739.66 791.78 CP-2S Shallow N/A 29.00 783.79 800.10 0.00 CP-2D Deep 107.00 705.95 800.03 CP-3S Shallow N/A 79.00 733.81 796.35 0.01 Downward CP-3D Deep 23.00 789.69 797.06 Gypsum Pad GP -IS Shallow N/A 59.00 801.13 802.10 0.00 GP-1 D Deep 109.00 751.00 802.09 GP-2S Shallow N/A 35.00 800.52 805.72 0.01 Downward GP-2D Deep 109.00 726.73 805.18 GP-3S Shallow N/A 59.00 799.46 805.41 0.00 GP-3D Deep 118.00 740.53 805.41 Page 3 of 4 TABLE 5-3 VERTICAL HYDRAULIC GRADIENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Reference Total Well Elevation mid - Water Level Point of Vertical Gradient Well ID Monitoring Zone Cross- Depth''2 Elevation Section (Ft-BGS) Screened 5-20-2019 and Flow Direction Interval Middle of Ash Basin AB-12S Ash Pore Water 15.91 784.70 790.71 A-A'/C-C' -0.01 Upward AB-12SL Ash Pore Water 54.97 747.70 791.13 AB-12SL Ash Pore Water A -A' 54.97 747.70 791.13 -0.06 Upward AB-12D Bedrock 73.69 728.06 792.23 AB-12D Bedrock A -A' 73.69 728.06 792.23 -0.10 Upward AB-12BR Bedrock 114.60 689.59 796.08 Notes: ' - .'Total Well Depth" is the depth to the bottom of the filter pack. 2 - Values measured during well installation BGS - Below ground surface ft - feet NAVD 88 - North American Vertical Datum 1988 Prepared by: GTC Checked by: BDW Page 4 of 4 TABLE 5-4 GROUNDWATER BALANCE SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Modeling Scenario Pre -Decanting Post -Decanting Closure -in -Place Closure -by -Excavation 3 0_ 0. 3 0- a 3 0_ 0 3 0 0 Water Balance Components 3 3 3 3 0 0, 0 0) o ai o 0) 0 0, o o, LL LL `-� LL ILL LL LL Direct recharge to the ash basin 136 170 112 Direct recharge to the watershed outside of 346 346 336 308 the ash basin Ash basin pond 80 16 157 Drainage inside the ash basin' 270 284 158 127 Drainage outside the ash basin 75 66 43 20 Domestic water supply wells 2 2 2 2 2 2 2 2 Flow through and under the dam 217 150 135 117 Prepared by: YAG Checked by: WCG Notes: 1) Drainage includes streams, seeps, ditch, channel, canal, etc. Drainage streams depend on the closure scenario, where the pre -decanting scenario includes streams present prior to closure and closure -by excavation includes streams that form within the excavated ash basin footprint after closure. Flow in refers to recharge to the groundwater system Flow out refers to discharge from the groundwater system gpm - gallons per minute Page 1 of 1 TABLE 5-5 SURFACE WATER CLASSIFICATION CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Adjacent Surface Water Body I Surface Water Classification (15A NCAC 02B .0300) Lake Norman Class B, WS-IV; CA Notes: 1. Class B waters are protected for primary recreation, which includes swimming on a frequent or organized basis and all Class C uses. 2. Class WS-IV waters are protected as water supplies that are generally in moderately to highly developed watersheds. WS-IV waters are also subject to Class C water quality standards. 3. CA - Critical area refers to an area adjacent to a water supply intake or reservoir where risk associated with impacts is greater than from other areas of the watershed NCAC - North Carolina Administrative Code WS - Water Supply Page 1 of 1 TABLE 6-1 BORON CONCENTRATIONS IN GROUNDWATER BELOW SOURCE AREA CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well Beneath Ash Number of Boron Concentration Range in Boron Concentration (Flow Zone) Sample Events Time Period of Record Groundwater Range in Overlying Pore Water 34.6 j - 190 AB-03D 16 07/2015 - 2/2019 (Note: One anomalous concentration of 4,370 220 - 1,700 (bedrock) ug/L (06/2016) was not confirmed through Saturated Ash: 55' dissolved result) AB-04D 14 07/2015 - 11/2018 344 - 390 146 - 850 (transition zone) Saturated Ash: 45' AB-05D 14 10/2015 - 2/2019 27.3 j - <50 (transition zone) 1,100 j+ - 2,750 M1 AB-05DU 3 08/2018 - 2/2019 33.4 j,B - 44.2 j (saprolite) Saturated Ash: 38' AB-05BR 15 07/2015 - 2/2019 <50 (bedrock) AB-06D 15 07/2015 - 2/2019 5,050 - 6,270 (bedrock) 235 - 8,140 AB-06BRA 244 - 1,210 (bedrock) 8 06/2017 - 2/2019 (Time series shows a spike and return to Saturated Ash: 42' -300 ug/L range; currently <2L) AB-06BRL 6 10/2017 - 2/2019 46.9 j - <250 (bedrock) AB-07D 13 07/2015 - 11/2018 25 - 107 (transition zone) 9,390 - 29,900 Saturated Ash: 10' AB-07DU (saprolite) 3 08/2018 - 2/2019 27.4 j - 236 AB-08D 12 09/2015 - 11/2018 30.6 j - 225 (bedrock) 405 - 1,500 Saturated Ash: 18' AB-08DU (saprolite) 3 08/2018 - 2/2019 45.3 j - 111 AB-10D 15 07/2015 - 2/2019 1,070 - 1,580 (bedrock) 9,350 - 27,400 Saturated Ash: 43' AB-10BR (bedrock) 10 12/2016 - 2/2019 216 - 383 AB-12D 15 07/2015 - 2/2019 928 - 3,500 (bedrock) 2,860 - 103,000 Saturated Ash: 48' AB-12BR (bedrock) 10 03/2017 - 2/2019 37.4 j - 94.6 B, lg AB-13D 12 09/2015 - 11/2018 26 j - <50 697 - 1,310 (bedrock) Saturated Ash: 40' AB-14D 14 07/2015 - 2/2019 130 - 502 (transition zone) 1,300 - 20,500 Saturated Ash: 30' AB-14DU (saprolite) 3 08/2018 - 2/2019 61.4 - 130 AB-15D 15 07/2015 - 2/2019 27.1 j - 55.9 (bedrock) 214 - 4,140 Saturated Ash: 33' AB-15BR (bedrock) 15 07/2015 - 2/2019 <50 - 54.2 AB-16D 12 09/2015 - 11/2018 26.3 j - 96.9 (bedrock) <50 - 166 Saturated Ash: 2' AB-16DU (saprolite) 3 08/2018 - 2/2019 <50 AB-17D 13 10/2015 - 11/2018 <50 - 179 6,000 - 27,600 (bedrock) Saturated Ash: 20' Page 1 of 2 TABLE 6-1 BORON CONCENTRATIONS IN GROUNDWATER BELOW SOURCE AREA CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well Beneath Ash Number of Boron Concentration Range in Boron Concentration (Flow Zone) Sample Events Time Period of Record Groundwater Range in Overlying Pore Water AB-18D 12 04/2016 - 11/2018 <50 - 61 (bedrock) 1,260 - 2,520 Saturated Ash: 24' AB-18DU (saprolite) 2 08/2018 - 11/2018 <50 AB-20D 14 07/2015 - 2/2019 25.6 j - 129 48,500 M6 - 80,600 (bedrock) Saturated Ash: 28' AB-21D 14 07/2015 - 2/2019 26 j - <50 1,100 - 5,770 (transition zone) Saturated Ash: 15' Prepared by: BDW Checked by: ECW Notes: < - less than j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j+ - Estimated concentration, biased high. M1 - Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable. M6 - Matrix spike and Matrix spike duplicate recovery not evaluated against control limits due to sample dilution. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 10X the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. 1g - Result confirmed by second analysis performed out of hold time. Page 2 of 2 TABLE 6-2 SOIL PSRG POG STANDARD EQUATION PARAMETERS AND VALUES CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Csoiil = Cgw [Kd + (ew + eaH')/Pb]df Inorganic Parameter Definition Default Values Units Parameters C5O1l Calculated source concentration NA mg/kg -soil for soil Applicable groundwater target Cg" concentration: 15A NCAC 02L 15A NCAC 02L Standard mg/L - water Standard df Dilution factor' (0.5 acre source 20 unitless size) Kd Soil -water partition coefficient Constituent Specific4 L/kg for inorganics (range) eW Water filled soil porosity - 0.3 Lwater/Lsoil vadose SOIISZ ea Air filled soil porosity - vadose 0.13 Lair/Lssoil 3 SOIIS Pb Dry bulk densityz 1.6 kg/L Henry's law constant - dimensionless where: H' _ H' Henry's law constant (atm - Constituent Specific3'5 unitless m3/mole) x conversion factor of 41 Prepared by: BDW Checked by: ECW Notes: ' - Default value from Soil Screening Guidance: Technical Background Document (USEPA, 1996) 2 - Site specific value (Falta et al., 2018). Effective porosity represents unconsolidated material 3 - DEQ default value appropriate for North Carolina 4 - Constituent Specific- Soil water partition coefficients (Kd) were obtained from the Groundwater Quality Signatures for Assessing Potential Impacts from Coal Combustion Product Leachate (EPRI, 2012). Chloride Kd ranges from 0 to 0.5, based on 0.25 soil, 0.5 for sand and 0-0.5 for sands, sediments. Sulfate Kd ranges from 0.1 to 2.1, based on sands/sediments and a pH range of 4.6 to 7.2 5 - a value of 0 is used for chloride and sulfate NA - Not applicable Page 1 of 1 TABLE 6-3 SUMMARY OF UNSATURATED SOIL SAMPLE ANALYTICAL RESULTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium* Cobalt Iron Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Vanadium Reporting Units mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater 0.9 5.8 580 63 45 3 938' 3.8 0.9 150 65 7.1 130 2.1 1500 1438' 0.28 350 2017 Background Threshold Values' 0.65 4.7 819 3.9 8.7 0.11 13 32.8 53 78,228 2,872 3.5 18.6 1.77 7.53 36 1.1 210 2019 Background Threshold ValueS2 0.64 8.2 1,063 3.9 15 0.72 293 406 63 78,228 3,388 3.5 237 3.7 200 293 2.1 210 Sample ID Sample Collection Date Analytical Results Background BG-3D (1-2) 6/9/2015 �5.�z 8.4 649 1.3 E5;1.33 <0.69 <278 420 27.4 37,600 243 <2.9 237 6.7 213 <278 S. 81.9 BG-3D (10-12) 6/9/2015 E53- 5.7 1,030 0.34 E52.9 <0.63 <262 406 28 34,300 412 <2.6 267 3.7 j 200 <262 �5.3 83.3 BGSB-GWA-02 (2-4) 8/16/2017 0.12 j,B,M 0.52 j,B 270 1.4 <15 <0.03 <2.6 19 28 44,000 M 1,300 M <12 N} 16 0.39 j 7.8 36 M 0.54 140 M BGSB-GWA-02 (8-10) 8/16/2017 <0.5 0.58 B 140 1.7 5.4 j 0.016 j 4 j,M 23 32 59,000 1,200 <2 10 <1.3 2.8 21 0.53 150 BGSB-GWA-02 (13-15) 8/16/2017 <0.59 0.63 B 180 1.6 <14 0.019 j 4.5 j 17 45 43,000 2,600 <2.2 17 <1.5 2.4 28 0.51 120 BGSB-GWA-02 (18-20) 8/16/2017 <0.59 0.47 j,B 180 1.5 1.6 j 0.031 3.9 j 15 70 27,000 1,900 <2.2 10 <1.5 5.3 18 0.75 120 BGSB-GWA-04 (2-4) 8/16/2017 <0.63 2.9 B 26 1.3 6.2 j <0.032 <13 13 3.2 53,000 120 2.3 j <12 0.44 j 0.9 j <13 0.32 120 BGSB-GWA-04 (8-10) 8/16/2017 <0.63 1.5 B 62 2.8 5.7 j <0.031 <13 16 6.4 61,000 240 E-14 <11 0.49 j <5.3 <13 0.23 150 BGSB-GWA-04 (13-15) 8/16/2017 <0.59 0.44 j,B 230 2.7 5.9 j <0.03 <12 14 36 56,000 1,700 E11 5.8 j 0.38 j <5.6 <12 0.58 140 BGSB-GWA-04 (15-17) 8/16/2017 <0.64 1.8 B 72 3.5 <14 <0.032 1.3 j 25 23 51,000 400 E44 <11 0.55 j <5.5 <13 0.19 170 BGSB-GWA-04 (18-20) 8/16/2017 <0.56 0.94 B 140 3.2 <15 0.11 <13 16 41 65,000 1,200 E3z <12 0.55 j <6 <13 0.86 160 BGSB-GWA-06 (2-4) 8/16/2017 0.24 j,B 2.1 B 20 0.58 2.6 j <0.03 <12 28 2.9 22,000 75 0.74 j 5.6 0.34 j 3.4 <12 0.31 54 BGSB-GWA-06 (8-10) 8/16/2017 <0.37 0.93 B 110 1.1 1.5 j <0.018 <12 6.9 15 18,000 400 1.1 j 6.7 0.38 j 1.8 <12 0.63 29 BGSB-GWA-06 (11-13) 8/16/2017 <0.54 1.9 B 99 1.9 1.2 j <0.027 1.3 j 21 21 20,000 270 0.83 j 9.6 0.63 j 4.3 <13 1.6 86 BGSB-GWA-06 (13-15) 8/16/2017 <0.46 0.68 B 33 0.59 <2.6 0.051 <11 11 40 6,000 770 3.5 4.2 <1.2 4.1 <11 0.32 5.4 BGSB-GWA-06 (18-20) 8/16/2017 <0.42 0.25 j,B 11 0.21 <2.6 <0.021 <11 0.38 j 6.3 170 32 <2.1 1 j <1.1 2.6 <11 0.06 j <1.1 GWA-2DA (3-5) 3/13/2017 r2.9 1 j 159 2.2 <6.6 <0.17 <63.1 10.8 22.6 38,900 361 <0.66 11.1 0.92 j 3.1 91.4 E1.4 97 GWA-2DA (8-10) 3/13/2017 E2.7 1.2 j 270 2.9 <7.2 <0.16 <59.7 16 16.7 33,400 734 <0.72 14.3 1.2 j 6 79 0.78 j 112 GWA-4D (52-53) 5/19/2015 <-6- <-6- 345 j+ 1.8 j- E559.8 <0.72 <293 15 23.2 j- 42,300 j- 810 j- <3 7.1 j- E� 16.5 <293 E-6- 128 j- GWA-5D (27.5-29.0) 7/1/2015 E?9- E?9- 490 2.6 <19.7 <0.94 <384 3.1 8.3 31,500 509 <3.9 4.5 <?9 60.7 <384 E7.9- 67.7 GWA-14S (3-5) 3/9/2017 E2.6 1.6 94.4 1.7 <6.4 <0.16 <56.1 2.4 4 18,300 334 <0.64 2.7 1.1 j 1.5 <56.1 E1.3 34 GWA-14S (8-10) 3/9/2017 E-3 3.8 45.1 1.3 <7.8 <0.19 <63.1 23.2 2 46,500 219 0.4 j 11.5 1.4 j 2.3 56.5 j E1.6 72.2 MAR 145 CCR Removal Verification Samples - West Finger Pond B-04 (0-1) 05/02/2019 <0.52 0.36 j 27 0.24 <2.6 <0.13 1.8 j 11 1.1 6,600 29 <2.1 3.1 <1.3 4.4 6.9 j 0.13 29 B-04 (2-3) 05/02/2019 <0.54 <0.54 48 0.48 <2.7 <0.14 <12 13 1.3 4,000 40 <2.2 3.4 0.63 j 10 <12 0.13 j 50 B-11 (0-1) 05/02/2019 <0.53 0.99 100 0.65 <5.3 0.029 j 3.8 j 52 5.2 37,000 230 4.7 19 1.7 2.9 <12 0.3 130 B-11 (2-3) 05/02/2019 <0.48 1.2 160 0.92 <19 0.034j <12 72 8 57,000 370 4.4 32 1.6 2.7 <12 0.59 110 B-11 (6.5-7.5) 05/02/2019 <0.45 2.2 1,100 1.3 <8.9 0.12 3 j 53 160 66,000 5,400 2.8 56 1.2 2.3 <12 3.9 78 C-06 (0-1) 05/02/2019 <0.58 0.62 91 1 <2.9 0.031 j 4.1 j 11 9.9 16,000 650 <2.3 17 <1.5 3 8 j 0.19 31 C-06 (2-3) 05/02/2019 <0.54 0.26 j 160 0.88 <2.7 0.067 j 1.9 j 13 9.4 10,000 890 <2.1 27 0.62 j 6.2 <12 0.33 21 C-08 (0-1) 05/02/2019 <0.62 <0.62 190 1.3 <3.1 0.14 j 1.4 j 27 9.6 21,000 220 <2.5 21 0.64 j 14 7.7 j 0.14 j 59 C-08 (2-3) 05/02/2019 <0.6 <0.6 200 1 <3 0.081 j 3.4 j 34 11 29,000 290 <2.4 15 <1.6 19 <14 0.19 49 C-08 (7-8) 05/02/2019 <0.57 <0.57 270 0.96 <2.9 0.23 2.3 j 11 14 28,000 800 <2.3 11 <1.5 19 <15 0.26 54 D-10 (0-1) 05/02/2019 <0.55 <0.55 610 0.93 <5.5 <0.14 7.2 j 36 14 52,000 440 <2.2 29 0.76 j 2.1 <13 0.36 82 D-10 (2-3) 05/02/2019 <0.56 0.25 j 380 0.76 <5.6 <0.14 6.7 j 51 13 52,000 360 <2.2 21 0.81 j 2.2 7.3 j 0.21 76 D-10 (7-8) 05/02/2019 <0.51 <0.51 440 1.3 <5.1 0.061 j 3.6 j 27 11 35,000 540 <2.1 18 <1.3 4.7 6.4 j 0.28 50 D-10 (12-13) 05/02/2019 -- <0.59 780 1.9 <8.8 0.15 3 j 49 24 56,000 2,000 <2.3 35 <1.5 3.4 <13 0.65 79 D-11 (0-1) 05/02/2019 <0.5 I <0.5 1 190 0.73 <20 <0.13 4.8 j 41 15 85,000 350 <2 26 0.66 j 4 <14 0.43 93 D-11 (2-3) 05/02/2019 <0.6 <0.6 320 1.3 <9 <0.16 4.3 j 44 17 49,000 460 <2.4 27 <1.6 2.5 <15 0.59 85 D-11 (7-8) 05/02/2019 <0.56 <0.56 250 1.2 <5.6 <0.15 2.3 j 68 14 48,000 290 <2.3 43 <1.5 2.4 <13 0.38 57 Page 1 of 4 TABLE 6-3 SUMMARY OF UNSATURATED SOIL SAMPLE ANALYTICAL RESULTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium* Cobalt Iron Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Vanadium Reporting Units mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater 0.9 5.8 580 63 45 3 938' 3.8 0.9 150 65 7.1 130 2.1 1500 1438' 0.28 350 2017 Background Threshold Values' 0.65 4.7 819 3.9 8.7 0.11 13 32.8 53 78,228 2,872 3.5 18.6 1.77 7.53 36 1.1 210 2019 Background Threshold ValueS2 0.64 8.2 1,063 3.9 15 0.72 293 406 63 78,228 3,388 3.5 237 3.7 200 293 2.1 210 Sample ID Sample Collection Date Analytical Results CAMA/Data Gap/Additional Source Areas Assessment Samples AB-02S (6-7) 07/01/2015 <5.5 2.8 j 74 0.79 <13.7 <0.66 <262 5.3 3.4 j 10,600 125 <2.7 1.6 <5.5 24.1 <262 <5.5 21.7 AL-01 (0.5-1) 04/12/2019 <0.44 3.4 150 0.58 1.2 j <0.11 <12 12 6.5 17,000 260 0.5 j 11 0.8 j 30 <12 0.24 38 AL-01 (2-3) 04/12/2019 <0.5 3.2 220 1.7 <7.4 0.025 j <12 20 7.8 37,000 230 <2 15 0.82 j 74 84 0.69 77 AL-01D (32-34) 06/30/2015 <5.9 10.5 319 2.4 <14.6 <0.7 <294 1 j 6.4 j 26,200 566 <2.9 1.5 j 7.1 82.6 <294 <5.9 54 CCR-05 (0.5-1) 04/16/2019 <0.41 0.61 190 0.77 0.98 j 0.077 j <11 14 11 20,000 540 <1.6 8.1 <1.1 26 41 0.33 47 CCR-05 (2-3) 04/16/2019 <0.41 0.54 260 0.38 1.7 j 0.065 j 10 j 14 14 38,000 780 <1.7 12 0.49 j 19 59 0.71 76 CCR-09 (0.5-1) 04/12/2019 <0.51 3.9 90 0.77 <5.1 <0.13 4.4 j 48 2.9 44,000 85 1.7 j 8 1.6 27 130 0.45 81 CCR-09 (2-3) 04/12/2019 <0.54 2.9 83 0.95 <8.1 <0.14 17 18 3.4 45,000 120 1.9 j 10 1.4 42 120 0.54 93 CP-01D (2-3) 03/15/2019 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA CP-01D (2-4) 03/15/2019 <0.59 1.7 170 1.3 <2.9 <0.15 11 j 14 7.8 25,000 350 <2.3 8.8 <1.5 34 65 0.48 57 CP-01D (4-6) 03/15/2019 <0.45 2 76 0.66 <2.3 <0.12 7.8 j 13 3.5 19,000 130 <1.8 6.3 <1.2 12 13 0.36 39 CP-01D (6-8) 03/15/2019 <0.61 1.9 44 0.8 <3 <0.16 13 16 3.1 26,000 130 <2.4 8.1 <1.6 10 77 0.4 52 CP-01D (8-10) 03/15/2019 <0.57 1.9 96 1 <2.8 <0.15 12 j 16 5.8 25,000 260 <2.3 8.5 <1.5 15 200 0.42 53 CP-02D (6-8) 03/18/2019 <0.45 0.98 130 1.2 <4.5 <0.12 2.7 j 16 8.5 25,000 730 <1.8 9.1 <1.2 21 14 0.42 49 CP-03D (0-2) 03/19/2019 0.22 j,M 4.7 100 0.73 3.6 j 0.074 j <11 20 7.6 66,000 M 400 M 4.1 17 <1.4 27 160 0.34 32 CP-03D (2-3) 03/19/2019 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA CP-03D (2-4) 03/19/2019 <0.5 1 0.24 j 160 1.2 <2.5 <0.13 4.1 j 4.2 5.8 19,000 420 <2 5.4 <1.3 13 260 0.45 46 CP-03D (4-6) 03/19/2019 <0.58 1.2 140 2.3 <2.9 0.031 j 7 j 25 15 25,000 380 <2.3 10 <1.5 12 <12 0.45 60 CP-03D (6-8) 03/19/2019 <0.56 2.1 70 2.3 <2.8 0.03 j 4.3 j 5.8 6.9 21,000 310 <2.3 2.6 <1.5 6.9 <12 0.29 41 CP-03D (8-10) 03/19/2019 <0.48 0.44 j 310 1.9 <4.8 0.05 j 4.1 j 74 12 34,000 720 <1.9 40 <1.3 16 230 0.72 75 GP-01D (0-5) 03/22/2019 <0.61 5.3 310 1.1 <6.1 <0.16 4.3 j 41 6.3 36,000 170 <2.4 24 1.2 j 130 1,500 0.4 84 GP-01D (2-3) 03/20/2019 NA <0.6 200 NA NA NA 8.3 j 1.9 2.7 6,800 120 NA 2.6 0.6 j NA <13 0.18 NA GP-01D (5-10) 03/22/2019 <0.69 0.37 j 330 2.1 <6.9 <0.18 6.7 j 76 18 52,000 400 <2.8 76 1.2 j 130 <13 0.65 97 GP-01D (10-15) 03/22/2019 <0.6 <0.62 970 1 <3 <0.16 5.9 j 130 18 38,000 390 <2.4 90 1.4 j 88 <13 0.77 16 GP-01D (15-20) 03/22/2019 <0.56 NA NA 2.2 <8.4 <0.15 NA NA NA NA NA <2.3 NA NA 72 NA NA 99 GP-01D (20-25) 03/22/2019 <0.62 0.56 300 3.4 <9.3 <0.16 3.5 j 110 45 33,000 880 <2.5 120 <1.5 390 <12 M 0.77 80 GP-01D (25-30) 03/22/2019 <0.56 0.33 j 400 2.3 <5.6 0.091 j 3.3 j 170 23 47,000 540 <2.2 120 <1.4 73 <11 0.82 79 GP-01D (30-35) 03/22/2019 <0.53 0.42 j 330 2.1 <7.9 0.04 j 2.9 j 160 16 49,000 330 <2.1 110 0.59 j 76 <13 0.65 82 GP-01D (35-40) 03/22/2019 <0.61 0.29 j 1530 2.3 <9.1 <0.16 3.2 j 12 14 31,000 580 <2.4 16 10.87 j 75 <12 0.79 87 GP-01D (40-45) 03/22/2019 <0.49 0.47 j 210 3.5 <4.9 0.041 j <12 53 7.9 21,000 430 <2 32 0.52 j 200 <12 0.41 87 GP-01D (45-50) 03/22/2019 <0.48 NA NA 2.2 1.1 j 0.086 j NA NA NA NA NA <1.9 NA NA 120 NA NA 56 GP-01D (47-49) 03/22/2019 NA 1.6 460 NA NA NA 14 j 16 8.5 46,000 420 NA 14 1.4 j NA 300 0.72 NA GP-02D (0-5) 03/29/2019 <0.6 0.89 100 1.1 <9 <0.16 3.3 j 18 4 39,000 250 <2.4 11 0.81 j 28 390 0.34 91 GP-02D (5-10) 03/29/2019 <0.57 <0.59 590 1.7 <5.7 <0.15 7 j 46 11 30,000 750 <2.3 34 <1.5 130 270 0.73 90 GP-02D (15-20) 03/29/2019 <0.59 <0.49 240 3.4 <5.9 0.086 j <12 8.3 2.6 13,000 500 <2.4 4.7 0.68 j 280 110 0.33 66 GP-02D (20-25) 03/29/2019 <0.49 1 0.61 280 1.6 1.4 j 0.033 j 9.4 j 13 8.8 39,000 520 <2 10 1.2 j 150 11 j 0.53 24 Page 2 of 4 TABLE 6-3 SUMMARY OF UNSATURATED SOIL SAMPLE ANALYTICAL RESULTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium* Cobalt Iron Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Vanadium Reporting Units mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater 0.9 5.8 580 63 45 3 938' 3.8 0.9 150 65 7.1 130 2.1 1500 1438' 0.28 350 2017 Background Threshold Values' 0.65 4.7 819 3.9 8.7 0.11 13 32.8 53 78,228 2,872 3.5 18.6 1.77 7.53 36 1.1 210 2019 Background Threshold ValueS2 0.64 8.2 1,063 3.9 15 0.72 293 406 63 78,228 3,388 3.5 237 3.7 200 293 2.1 210 Sample ID Sample Collection Date Analytical Results GP-03D (0-5) 03/25/2019 <0.56 M 0.28 j 320 1.4 <5.9 <0.14 2.8 j 4.6 B 7 36,000 B,M 470 <2.4 3.9 1.6 75 110 M 0.75 76 GP-03D (2-3) 03/25/2019 NA <0.64 1100 NA NA NA 6.6 j 57 B 39 23,000 B 1,100 NA 50 2.8 NA 860 0.71 NA GP-03D (5-10) 03/25/2019 <0.62 0.8 720 2.3 4 j <0.16 9.1 j 62 B 140 28,000 B 4,300 <2.5 58 1.5 j 30 670 1.9 120 GP-03D (10-15) 03/25/2019 <0.64 0.99 320 3.1 <3.2 0.049 j 6.9 j 180 B 16 38,000 B 610 <2.6 49 1.7 320 680 0.44 56 GP-03D (15-20) 03/25/2019 <0.6 NA NA 2.5 <3 0.25 NA NA NA NA NA <2.4 NA NA 180 NA NA 71 GP-03D (20-25) 03/25/2019 <0.57 <0.62 450 2.9 2.6 j 0.053 j 6.1 j 290 B 23 65,000 B 480 <2.3 160 3.4 110 670 0.96 64 GWA-01BR (8-10) 06/26/2015 <5.7 NA NA 1.9 <14.3 <0.69 NA NA NA NA NA <2.9 NA NA 19.8 NA NA 30.4 GWA-01BR (14-15.5) 06/26/2015 NA <6.2 118 NA NA NA <297 13.4 7.1 18,100 192 NA 9.5 <6.2 NA <297 <6.2 NA GWA-01BR (18-20) 06/26/2015 <6.2 <5.7 128 1.4 <15.5 <0.74 <302 6 9.1 16,000 529 <3.1 5.3 <5.7 12.2 <302 <5.7 46.7 GWA-07 (0.5-1) 04/12/2019 <0.43 0.76 99 0.68 <2.1 <0.11 <11 51 11 13,000 550 <1.7 24 0.49 j 28 <11 0.21 30 GWA-07 (2-3) 04/12/2019 <0.51 2 140 0.8 <2.5 <0.13 <12 92 13 22,000 500 <2 41 0.49 j 46 41 0.37 52 ILF-01BR (0-5) 03/13/2019 <0.63 M 1.9 150 2 3.3 <0.16 8.7 j 22 6.6 28,000 M 220 0.68 j 11 0.62 j,M 64 M 49 0.41 70 ILF-01BR (5-10) 03/13/2019 <0.56 <0.47 82 1.2 2.7 j <0.15 1.9 j 2 3.7 14,000 460 0.59 j 1.3 j <1.2 22 <11 0.26 50 ILF-01BR (10-15) 03/13/2019 <0.47 <0.47 100 1.1 <2.3 <0.12 3 j 2.1 3.8 16,000 360 <1.9 1.4 j <1.2 27 <11 0.31 23 ILF-01BR (15-20) 03/13/2019 <0.47 0.5 140 0.91 0.96 j 0.028 j 2.1 j 12 4 19,000 400 <1.9 5.5 <1.3 25 <11 0.38 26 ILF-01BR (20-25) 03/13/2019 <0.49 0.23 j 220 0.85 1.1 j 0.024 j 3.3 j 11 6.5 22,000 380 <2 5.2 <1.3 33 <11 0.47 32 ILF-01BR (25-30) 03/13/2019 <0.49 0.47 300 0.53 1.4 j 0.065 j 2.5 j 17 9.7 32,000 420 <1.9 7.8 <1.2 33 <11 0.55 56 ILF-01BR (30-35) 03/13/2019 <0.47 0.66 160 0.77 <4.7 0.041 j 5.7 j 12 6.1 23,000 380 <1.9 7.3 <1.5 63 6.3 j 0.36 71 ILF-02D (7-10) 03/31/2019 <0.59 <0.58 340 1.5 <5.9 <0.15 5.3 j 21 14 38,000 760 <2.4 8.3 0.61 j 22 <13 0.91 72 ILF-02D (10-15) 03/31/2019 <0.58 0.3 j 370 1.6 <5.8 0.049 j 6.3 j 20 12 29,000 590 <2.3 14 <1.6 20 <13 0.61 76 ILF-02D (15-20) 03/31/2019 <0.63 <0.53 310 1.1 2.9 j <0.16 3.2 j 15 8.1 29,000 460 <2.5 6.7 0.52 j 25 <11 0.77 67 ILF-02D (20-25) 03/31/2019 <0.53 0.46 j 180 1.6 <7.9 0.026 j <12 13 8 30,000 620 <2.1 5 <1.4 26 <12 0.32 66 ILF-02D (25-30) 03/31/2019 <0.55 <0.58 320 2.4 <8.2 0.1 j 3.2 j 18 9.8 34,000 510 <2.2 7.3 <1.5 44 <12 0.63 62 ILF-02D (30-35) 03/31/2019 <0.58 <0.55 290 2.1 <5.8 0.056 j 2.9 j 16 8.1 28,000 490 <2.3 6.3 <1.4 44 <12 0.56 67 ILF-02D (35-40) 03/31/2019 <0.55 <0.59 280 2.3 <5.5 0.14 6.7 j 21 9.7 34,000 530 <2.2 8.9 0.66 j 39 <13 0.85 62 MW-05 (0.5-1) 04/12/2019 <0.59 3.1 160 1.6 <8.8 <0.15 3.3 j 22 8.3 38,000 150 <2.4 15 0.75 j 120 100 0.42 79 MW-05 (2-3) 04/12/2019 <0.49 1.5 170 1.4 <7.4 <0.13 11 j 12 6.3 32,000 220 <2 9.3 0.64 j 120 <13 M 0.41 50 MW-10 (0.5-1) 04/12/2019 <0.6 1.7 88 1.3 <6 <0.16 2.8 j 110 6 35,000 190 <2.4 79 0.98 j 9.5 56 0.45 68 MW-10 (2-3) 04/12/2019 <0.63 M 0.91 M 150 1.3 <5.7 <0.16 14 61 6.4 33,000 M 360 M <2.3 M 48 0.79 j 6.9 <13 0.65 64 M MW-14BR (31.5-33) 07/10/2015 <6.5 <6.5 828 6.3 <3.3 <0.78 <329 61.9 16.8 50,400 421 3 45.2 <6.5 19.1 <329 <6.5 128 PVSF-01BR (2-4) 03/18/2019 <0.46 0.53 j 630 1.3 <6.9 <0.12 3.2 j 3.7 17 42,000 650 <1.8 5.7 <1.4 450 130 0.68 86 PVSF-01BR (4-6) 03/18/2019 <0.46 0.7 530 1 <6.9 <0.12 3.8 j 8.6 11 53,000 490 <1.8 7.4 <1.4 120 150 0.66 94 PVSF-01BR (8-10) 03/18/2019 <0.64 M 0.67 570 1.2 <5.1 <0.17 5.9 j 2 13 50,000 530 <2.1 4.5 0.49 j 310 M 85 M 0.6 69 PVSF-01BR (10-12) 03/18/2019 <0.55 0.39 j 730 1 <8.3 0.041 j 5.7 j 6.1 11 39,000 440 <2.2 6.5 <1.3 290 <12 0.5 93 PVSF-01BR (12-14) 03/18/2019 <0.55 0.37 j 740 1.3 <8.2 <0.14 4.5 j 4.3 21 35,000 710 <2.2 5.5 0.51 j 160 <11 M 0.55 120 PVSF-01BR (14-16) 03/18/2019 <0.49 0.44 j 500 1.2 <7.4 <0.13 6.7 j 1.8 13 43,000 520 <2 3.7 <1.3 230 <12 0.7 110 PVSF-01BR (16-18) 03/18/2019 <0.5 0.52 590 2 <5 <0.13 5.3 j 4.1 15 44,000 580 <2 5 <1.1 260 <12 0.61 96 PVSF-01BR (18-20) 03/18/2019 <0.45 1.4 630 1.9 <4.5 0.041 j 3.6 j 10 6.5 45,000 360 <1.8 12 0.72 j 290 330 0.5 75 PVSF-01BR (20-22) 03/18/2019 <0.5 0.48 690 1.6 <7.5 <0.13 5.5 j 1.9 58 37,000 2,500 <2 3.4 <1.2 70 <11 M 0.72 92 PVSF-01BR (22-24) 03/18/2019 <0.43 0.37 j 780 1.7 <6.4 0.027 j 8.6 j 2.9 14 40,000 530 <1.7 4 <1.3 160 <13 0.6 92 PVSF-01BR (24-26) 03/18/2019 <0.47 0.56 680 1.9 <7.1 0.031 j 5.8 j 1.6 42 53,000 1,900 0.52 j 8.1 <1.2 260 <11 1.1 80 Page 3 of 4 TABLE 6-3 SUMMARY OF UNSATURATED SOIL SAMPLE ANALYTICAL RESULTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium* Cobalt Iron Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Vanadium Reporting Units mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater 0.9 5.8 580 63 45 3 938' 3.8 0.9 150 65 7.1 130 2.1 1500 1438' 0.28 350 2017 Background Threshold Values' 0.65 4.7 819 3.9 8.7 0.11 13 32.8 53 78,228 2,872 3.5 18.6 1.77 7.53 36 1.1 210 2019 Background Threshold ValueS2 0.64 8.2 1,063 3.9 15 0.72 293 406 63 78,228 3,388 3.5 237 3.7 200 293 2.1 210 Sample ID Sample Collection Date Analytical Results PVSF-01BR (26-28) 03/18/2019 <0.49 0.33 j 520 1.7 <7.4 0.025 j 6.1 j 4.7 9.7 41,000 470 <2 3.5 <1.4 350 <13 0.5 89 PVSF-01BR (28-30) 03/18/2019 <0.47 0.51 570 1.6 <12 0.12 5.2 j 5 11 41,000 510 0.6 j 4.1 <1.2 160 <11 M 0.49 100 PVSF-01BR (30-32) 03/18/2019 <0.52 0.52 520 1.6 <5.2 <0.14 3.9 j 2.6 12 41,000 610 <2.1 3.5 <1.1 170 <11 0.55 85 PVSF-01BR (32-34) 03/18/2019 <0.46 0.79 420 1.6 <6.8 0.024 j 11 j 6.1 8.7 48,000 390 <1.8 7.5 0.49 j 200 <12 0.57 82 PVSF-01BR (34-36) 03/18/2019 <0.44 4.9 560 1.5 <6.6 0.047 j 7.6 j 3.8 6.6 35,000 M 320 M <1.8 5.1 1 j 160 150 0.45 84 PVSF-03BR (0-2) 03/26/2019 <0.64 2.9 64 1.2 5.9 j 0.039 j NA 47 5.6 67,000 130 2.7 21 1.1 j 3.1 130 0.35 180 PVSF-03BR (2-3) 03/26/2019 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA PVSF-03BR (2-4) 03/26/2019 <0.7 1.3 83 1.2 5.5 j 0.036 j NA 35 7 79,000 350 0.7 j 18 0.93 j 1.1 j 11 j 0.25 180 PVSF-03BR (4-6) 03/26/2019 <0.66 0.95 73 1.1 5.6 j 0.049 j NA 37 9.3 76,000 290 <2.6 18 0.69 j 0.61 j <15 0.16 j 190 PVSF-03BR (6-8) 03/26/2019 <0.74 0.56 j 63 1.2 <18 0.08 j NA 38 20 85,000 600 <2.9 16 <1.9 0.38 j 9.4 j 0.1 j 190 PVSF-03BR (8-10) 03/26/2019 <0.75 0.54 j 66 1.3 4.4 j 0.096 j NA 32 29 67,000 850 <3 17 <1.9 <1.5 12 j 0.095 j 180 PVSF-04D (2-3) 07/24/2019 <0.57 0.79 190 1.2 <8.7 <0.15 2.7 j 62 5 53,000 68 1 j 23 0.61 j 2.7 <12 M 0.9 81 PVSF-04D (7-8) 07/24/2019 <0.58 0.27 j 440 3 <12 0.047 j 6.6 j 59 12 54,000 390 4.3 41 0.77 j 3.8 <12 1.1 130 PVSF-04D (12-13) 07/24/2019 <0.58 0.91 350 2.3 <6.1 0.034 j 4.5 j 60 14 52,000 320 2.3 j 27 <1.5 7.4 6.6 j 1.2 90 PVSF 04S (15-16) 07/24/2019 <0.55 0.34 j 130 1.1 <2.4 <0.14 <12 4.8 3.6 11,000 230 0.54 j 4.9 <1.4 46 75 0.42 20 SS-01 (0.5-1) 04/16/2019 <0.5 M 0.5 340 2.6 <5.6 0.036 j 5.3 j 27 9 36,000 M 510 M <2.3 17 1.3 120 63 0.5 81 SS-01 (2-3) 04/16/2019 <0.6 M 0.32 j,M 310 1.9 <4.8 1 0.041 j 1 16 11 23 M 36,000 M 570 M <1.9 M 11 0.62 j 86 480 0.58 78 M Notes• 1 - Background threshold values were calculated using data from background unsaturated soil samples collected May 2015 to March 2017. Z - Background threshold values were calculated using data from background unsaturated soil samples collected May 2015 to August 2018. 3 - The PSRG POG displayed was calculated in accordance with Table 6-2 presented in the CAP Update Report text. bold highlighted concentration indicates value is greater than applicable regulatory standard (PSRG POG) bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard PSRG - Preliminary Soil Remediation Goals for the Protection of Groundwater (POG); NCDEQ Inactive Hazardous Sites Branch (IHSB) Preliminary Soil Remediation Goals Table (February 2018) * - North Carolina PSRG POG is for hexavalent chromium, soil analytical is for total chromium. < - Concentration not detected at or above the adjusted reporting limit. mg/kg - milligrams per kilogram <7.9 - Strike -through indicates that the non -detect was omitted from the dataset because the reporting limit for the non -detect was greater than the protection of groundwater preliminary soil remediation goal. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 10X the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j- - Estimated concentration, biased low. j+ - Estimated concentration, biased high. M - Matrix spike / matrix spike dup failure. Prepared by: BDW/ECW Checked by: KHG Page 4 of 4 TABLE 6-4 SOURCE AREA INTERIM ACTIONS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Groundwater Remedy Component Rationale Active source remediation by removing ponded water in the ash basin. Decanting will lower the hydraulic head within the coal ash basin and Ash Basin Decanting reduce hydraulic gradients, reducing groundwater seepage velocities and COI transport potential. Decanting will return the groundwater flow system to its approximate natural condition, flowing toward the axis of the perennial stream valley, then east. Groundwater data at the Site indicates that surrounding water supply wells are not affected by Site -related COIs. However, Duke Energy installed 62 connections to public water supply and maintains 3 water filtration systems for qualifying occupied households. Six additional Permanent Water Supply Solution for Water properties, including businesses and churches, within a 0.5-mile radius Well Users of the MSS compliance boundary were also provided permanent water solutions by Duke Energy, although they did not meet the eligibility requirements outlined in G.S. Section 130A-309.211(cl). Duke Energy's actions were approved by NCDEQ, which addresses stakeholder concerns. Dam modifications include tree removal, installation of an aggregate Source Area Stabilization seepage collection and filter overlay system, and installation of flumes, riprap channels, and storm water culverts, riprap lined ditches, seepage collection berm and a concrete ditch. Notes: COI - Constituent of Interest NCDEQ - North Carolina Department of Environmental Quality Prepared by: WCG Checked by: ECW Page 1 of 1 TABLE 6-5 MEANS OF GROUNDWATER COIs - FEBRUARY 2018 TO MAY 2019 CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium (VI) Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 10 1* 300 NE 50 NE 100 20 NE 250 0.2* 500 5^ 0.3* 2018 Background Threshold Values (Shallow Flow Zone) 0.5 310 0.2 50 0.08 5.5 irr5.7 16.5 1.2 744 --- 75.3 9.9 1 0.1 140 3.0 2019 Background Threshold Values (Shallow Flow Zone)21 0.79 1 1 580 0.223 1 50 1.0 5.0 7.0 16.8 5.0 1095 14.8 155 1.0 19.6 1.0 210 1 11.3 0.2 152.4 5.33 13.0 Background Data Set Range (Shallow Flow Zone) 0.1 j - 1.12 0.043 j - 1.7 22.2 - 730 0.012 j - 0.61 3.3 - 56.7 0.052 j - 0.101 0.92 - 5.4 0.076 j - 7.1 0.1 j - 39.2 0.041 j - 5.2 28 - 3440 0.19 j - 5.6 1.46 j - 390 0.076 j - 1.4 0.28 j - 21.9 0.092 - 0.72 9 - 223 0.0447 j - 12.8 0.015 j - 0.024 10 - 144 0.049 - 6.73 0.077 j - 15.4 2018 Background Threshold Values (Deep Flow Zone)' 127 0. 50 0.08 4.7 7.6 1.9 272 --- 141 665 17.7 0.1 183 2.8 2019 Background Threshold Values (Deep Flow Zone) 0.62 1.4 138 0.2 50 0.08 4.2 6.0 4.3 3.2 225 10.0 142 7.3 7.8 2.4 727 24.2 0.1 200 7.46 3.9 Background Data Set Range Dee Flow Zone 9 9( P ) 0.14'-1.3 J 0.088'-1.9 ] 15.1-146 0.012'-0.095' J J 2.3'-43' ] J 0.03'-0.054' J J 1.2-4.8 0.01 2.7 J- 0.15'-3.1 J 0.013'-3.3 ] 30.4'-310 ] 2.5-10.9 7.4-154 0.19 10.5 j- 0.13 7.9 j- 0.17j-2.9 J 81.4-732 2.3-35.4 0.018j-0.054 41-202 0.2587-11.14 0.74-4 2018 Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 3.0 7.2 1 253 0.1 216 5.77M 2019 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1,220 11.4 330 3.7 8.0 1.0 313 22.1 0.2 19-9 6.43 25.8 Background Data Set Range (Bedrock Flow Zone) 0.11-1.25 0.071 j-2.3 23-857 0.01j-1.8 25.9j-49.1j 0.054j-1.9 1.2-4 0.012j-11.8 0.23j-31 0.026j-3.9 16-1530 3.8-11 2.8j-385 0.13j-6.2 0.33j-22.8 0. 17j-2.3 140-407 0.42j-23.9 0.016j-0.069 j 42-240 4.6E-05j- 1.5E-04 j 0.099j-26.6 Sample ID Flow Zone Analytical Results Background Locations BG-01S Shallow < 0.5 0.10 48 < 0.1 < 50 < 0.08 3.0 3.3 4.3 0.20 324 < 0.5 7.5 < 0.5 3.8 < 0.5 111 8.3 < 0.1 88 0.51 0.88 BG-011) Deep < 0.5 0.16 132 < 0.1 < 50 < 0.08 3.1 2.7 2.8 0.20 81 10.0 11 < 0.5 5.0 2.3 689 9.1 < 0.1 137 2.3 3.5 BG-0IBRA Bedrock < 0.5 0.18 441 < 0.1 < 50 < 0.08 2.4 2.4 2.9 0.26 110 6.6 22 0.59 2.3 < 0.5 197 2.1 < 0.1 146 2.3 18 BG-02S Shallow < 0.5 0.14 294 < 0.1 < 50 < 0.08 1.7 4.7 5.6 0.10 407 4.5 5.5 < 0.5 3.9 < 0.5 179 5.8 < 0.1 115 1.2 8.3 BG-02BR Bedrock < 0.5 0.17 468 < 0.1 < 50 < 0.08 2.4 7.9 7.1 < 0.1 < 50 8.3 < 5 < 0.5 1.0 < 0.5 239 2.9 < 0.1 153 5.1 14 BG-03S Shallow < 0.5 0.23 426 < 0.1 < 50 < 0.08 1.8 5.9 8.9 0.25 414 4.3 6.7 < 0.5 11 < 0.5 126 8.5 < 0.1 122 0.85 6.3 BG-03D Bedrock < 0.5 0.38 788 < 0.1 < 50 < 0.08 2.6 5.3 5.1 < 0.1 52 7.3 < 5 < 0.5 4.7 < 0.5 156 11 < 0.1 181 0.99 25 BG-03BR Bedrock < 0.5 0.46 65 < 0.1 < 50 0.08 2.5 3.8 5.7 0.41 620 10 11 1.8 5.2 < 0.5 180 11 < 0.1 181 1.4 16 GWA-04D Deep < 0.5 0.81 27 < 0.1 < 50 < 0.08 3.3 0.10 0.57 < 0.1 51 3.7 66 4.3 0.59 < 0.5 139 7.8 < 0.1 179 1.2 1.3 GWA-04S Shallow < 0.5 0.13 33 < 0.1 < 50 < 0.08 3.6 0.93 2.0 0.15 394 0.86 12 < 0.5 1.0 < 0.5 40 < 1 < 0.1 61 0.55 0.50 GWA-05D Deep < 0.5 0.12 17 < 0.1 < 50 < 0.08 1.5 0.42 0.57 < 0.1 < 50 3.0 < 5 < 0.5 < 0.5 < 0.5 84 2.6 < 0.1 66 1.1 1.5 GWA-06D Bedrock < 0.5 0.17 25 < 0.1 56 < 0.08 2.9 0.66 0.94 0.54 116 6.1 24 0.73 0.89 < 0.5 234 7.6 < 0.1 104 0.38 1.5 GWA-06S Shallow < 0.5 0.23 62 0.12 51 < 0.08 2.9 0.45 1.1 < 0.1 393 0.63 11 < 0.5 1.0 < 0.5 56 < 1 < 0.1 54 0.77 0.54 GWA-08D Bedrock < 0.5 0.22 31 < 0.1 < 50 < 0.08 2.7 0.42 0.88 < 0.1 190 5.7 11 < 0.5 0.54 < 0.5 176 < 1 < 0.1 83 - 3.4 GWA-08S Shallow < 0.5 0.11 27 < 0.1 < 50 < 0.08 4.7 1.0 4.6 0.14 268 3.1 7.6 < 0.5 1.2 0.57 203 3.4 < 0.1 77 - 3.5 GWA-12BR Bedrock < 0.5 0.34 29 < 0.1 < 50 < 0.08 1.5 0.04 < 0.5 1.2 328 9.1 250 2.2 2.0 < 0.5 180 21 < 0.1 112 1.4 < 0.3 GWA-12S Shallow < 0.5 0.11 44 < 0.1 < 50 < 0.08 2.6 0.58 0.83 0.35 73 0.59 16 < 0.5 1.2 < 0.5 10 3.9 < 0.1 30 1.1 < 0.3 MS-10 Shallow < 0.5 < 0.1 111 0.22 < 50 < 0.08 1.2 0.70 1.0 0.62 236 2.3 22 < 0.5 1.4 < 0.5 16 < 1 < 0.1 28 1.5 0.54 MW-04 Shallow < 0.5 0.15 52 < 0.1 < 50 < 0.08 1.9 1.6 2.3 < 0.1 73 0.86 < 5 < 0.5 0.8 < 0.5 103 < 1 < 0.1 55 0.88 1.1 MW-04D Bedrock < 0.5 0.13 41 < 0.1 < 50 < 0.08 1.4 0.38 0.54 < 0.1 58 4.3 < 5 < 0.5 < 0.5 < 0.5 195 1.3 < 0.1 84 0.79 2.6 Shallow Flow Zone AB-01S Shallow < 0.5 1.9 58 0.72 3978 0.28 169 0.06 0.92 14 715 1.4 2819 0.64 1.5 1.7 711 106 0.34 556 3.1 1.6 AB-02S Shallow < 0.5 0.18 33 < 0.1 < 50 < 0.08 3.1 0.03 0.96 16 1298 < 0.5 845 < 0.5 0.96 < 0.5 12 3.0 0.19 36 1.0 < 0.3 AB-05DU Shallow < 0.5 0.29 302 < 0.1 40 0.20 3.9 < 0.025 0.63 44 2765 9.9 4220 0.24 13 < 0.5 1595 52 < 0.1 248 1.4 1.5 AB-07DU Shallow < 0.5 1.3 166 0.06 107 < 0.08 2.8 < 0.025 2.7 8.5 3088 5.1 397 0.81 11 < 0.5 916 14 < 0.1 169 0.91 1.3 AB-08DU Shallow < 0.5 0.37 190 < 0.1 78 < 0.08 3.9 0.06 1.4 2.6 1156 3.4 466 0.51 9.4 < 0.5 1223 68 < 0.1 219 0.77 0.34 AB-095 Shallow < 0.5 0.50 37 < 0.1 48 < 0.08 1.7 0.50 4.7 1.1 1095 < 0.5 143 < 0.5 4.4 < 0.5 72 11 0.14 78 - 1.2 AB-11S Shallow < 0.5 0.24 12 < 0.1 < 50 < 0.08 1.9 0.34 0.64 0.66 166 0.97 62 < 0.5 < 0.5 < 0.5 43 < 1 < 0.1 35 - 0.58 AB-14DU Shallow < 0.5 0.19 118 < 0.1 95 < 0.08 1.8 0.97 3.1 1.2 178 2.3 214 0.49 1.3 < 0.5 281 17 < 0.1 109 0.47 1.8 AB-16DU Shallow < 0.5 0.75 182 < 0.1 < 50 < 0.08 8.2 0.03 1.1 15 1211 5.4 623 2.0 7.3 < 0.5 776 18 < 0.1 232 0.64 1.5 AB-165 Shallow < 0.5 7.4 107 < 0.1 99 < 0.08 2.3 0.03 0.54 18 60900 0.55 1940 0.53 3.7 0.57 302.5 21 < 0.1 179 - 0.74 AL-01S Shallow < 0.5 1.2 83 4.6 3978 0.45 190 0.16 3.3 6.0 374 7.1 1796 < 0.5 2.7 1.4 2182 94 0.20 511 2.3 0.39 AL-02S Shallow < 0.5 0.30 40 1.0 12633 0.91 1.9 1.1 2.5 0.29 124 5.6 282 0.51 19 87 5530 1433 < 0.1 2422 - 0.87 CCR-01S Shallow < 0.5 0.18 99 0.35 < 25 < 0.08 4.0 < 0.025 < 0.5 2.9 81 < 2.5 382 < 0.5 1.3 < 0.5 125 0.87 < 0.1 81 0.85 1.2 CCR-025 Shallow < 0.5 0.12 68 0.13 125 0.09 6.3 0.05 < 0.5 8.2 43 < 2.5 684 < 0.5 1.2 < 0.5 59 9.4 0.11 62 0.93 0.87 CCR-03S Shallow < 0.5 0.11 32 0.13 < 50 0.09 3.1 0.37 0.70 0.21 25 < 2.5 1.2 < 0.5 < 0.5 < 0.5 543 < 1 < 0.1 39 0.79 0.73 CCR-045 Shallow < 0.5 0.74 88 0.74 287 0.65 9.3 - < 0.5 116 - 1.6 - < 0.5 - 0.52 - 136 0.70 277 1.5 - CCR-OSS Shallow < 0.5 0.66 110 0.06 177 < 0.08 12 - < 0.5 0.92 - 0.44 - 0.31 - < 0.5 - 80 < 0.1 284 1.5 - CCR-095 Shallow 0.52 1.0 129 2.2 3805 0.70 174 1.4 3.0 111 68 6.8 3835 < 0.5 3.7 1.2 116 88 0.27 464 1.2 < 0.3 CCR-11S Shallow < 0.5 2.5 49 1.1 5037 0.17 201 - 0.88 62 - 6.9 - < 0.5 - 1.5 - 98 3.0 343 2.4 - CCR-125 Shallow < 0.5 1.2 965 5.0 3897 0.89 226 - 1.3 83 - 1.7 - < 0.5 - 0.61 - 24 0.70 476 7.6 - CCR-13S Shallow < 0.5 50 109 < 0.1 3263 < 0.08 136 < 0.025 0.72 9.8 7050 37 2910 42 2.7 < 0.5 2040 167 0.37 824 1.9 < 0.3 CCR-145 Shallow < 0.5 0.64 499 0.89 3780 0.18 235 - 1.1 9.9 - 0.71 - < 0.5 - < 0.5 - 59 0.15 491 5.8 - CCR-1SS Shallow < 0.5 0.16 12 0.16 5.6 < 0.08 1.8 - 2.4 0.38 - 0.43 - < 0.5 - < 0.5 - 0.87 < 0.1 36 0.63 - CCR-165 Shallow < 0.5 0.19 45 0.15 10 < 0.08 4.3 - 1.3 0.63 - 0.73 - < 0.5 - 0.60 - 20 < 0.1 78 0.44 - CP-01S Shallow 0.11 3.2 30 5.4 218 0.86 11 0.07 0.58 274 69167 8.9 4383 < 0.5 56 2.8 514 304 1.3 638 0.80 0.50 CP-02S Shallow < 0.5 0.16 21 < 0.1 < 50 < 0.08 2.9 0.05 < 0.5 27 12313 < 2.5 1877 1.5 2.0 < 0.5 65 1.5 0.06 277 0.94 0.31 CP-03S Shallow < 0.5 0.11 93 0.10 111 < 0.08 12 0.45 2.2 0.51 73 2.7 91 0.44 1.9 0.38 97 39 < 0.1 135 0.73 0.24 GP-01S Shallow 0.18 0.20 80 0.07 < 50 < 0.08 1.9 0.64 5.3 0.94 128 < 2.5 94 0.66 9.5 < 0.5 223 5.5 < 0.1 95 1.1 1.8 GP-02S Shallow < 0.5 0.12 124 0.10 < 50 < 0.08 1.8 1.9 2.7 0.89 263 < 2.5 54 0.21 0.93 0.97 609 19 < 0.1 111 1.7 0.77 GP-03S Shallow < 0.5 0.08 49 < 0.1 < 50 < 0.08 2.9 0.04 < 0.5 0.48 < 50 < 2.5 52 0.53 0.74 < 0.5 106 2.3 < 0.1 66 1.0 0.45 GWA-01S Shallow 0.52 < 0.1 49 0.71 < 50 < 0.08 2.9 0.48 0.89 0.54 116 1.3 16 < 0.5 1 0.62 1.5 33 9.4 < 0.1 60 0.88 0.41 GWA-02S Shallow < 0.5 0.15 68 0.18 < 50 0.08 1.5 2.5 3.5 0.58 78 < 2.5 44 < 0.5 1.3 0.90 29 34 0.11 111 1 0.52 1 33 GWA-03S Shallow < 0.5 < 0.1 32 0.10 < 50 < 0.08 2.1 0.31 0.53 < 0.1 147 1.6 12 < 0.5 < 0.5 < 0.5 41 0.85 < 0.1 67 - 0.63 Page 1 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - FEBRUARY 2018 TO MAY 2019 CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium (VI) Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 10 1* 300 NE 50 NE 100 20 NE 250 0.2* 500 5^ 0.3* 2018 Background Threshold Values (Shallow Flow Zone) 0.5 310 0.2 50 0.08 5.5 irr5.7 16.5 1.2 744 --- 75.3 9.9 1 0.1 140 3.0 2019 Background Threshold Values (Shallow Flow Zone)21 0.79 1 1 580 0.223 1 50 1.0 5.0 7.0 16.8 5.0 1095 14.8 155 1.0 19.6 1.0 210 1 11.3 0.2 152.4 5.33 13.0 Background Data Set Range (Shallow Flow Zone) 0.1 j - 1.12 0.043 j - 1.7 22.2 - 730 0.012 j - 0.61 3.3 - 56.7 0.052 j - 0.101 0.92 - 5.4 0.076 j - 7.1 0.1 j - 39.2 0.041 j - 5.2 28 - 3440 0.19 j - 5.6 1.46 j - 390 0.076 j - 1.4 0.28 j - 21.9 0.092 - 0.72 9 - 223 0.0447 j - 12.8 0.015 j - 0.024 10 - 144 0.049 - 6.73 0.077 j - 15.4 2018 Background Threshold Values (Deep Flow Zone)' 127 0. 50 0.08 4.7 7.6 1.9 272 --- 141 665 17.7 0.1 183 2.8 2019 Background Threshold Values (Deep Flow Zone) 0.62 1.4 138 0.2 50 0.08 4.2 6.0 4.3 3.2 225 10.0 142 7.3 7.8 2.4 727 24.2 0.1 200 7.46 3.9 Background Data Set Range Dee Flow Zone 9 9( P ) 0.14'-1.3 J 0.088'-1.9 ] 15.1-146 0.012'-0.095' J J 2.3'-43' ] J 0.03'-0.054' J J 1.2-4.8 0.01 2.7 J- 0.15'-3.1 J 0.013'-3.3 ] 30.4'-310 ] 2.5-10.9 7.4-154 0.19 10.5 j- 0.13 7.9 j- 0.17j-2.9 J 81.4-732 2.3-35.4 0.018j-0.054 41-202 0.2587-11.14 0.74-4 2018 Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 26.6 3.0 7.2 1 253 0.1 216 5.7 2019 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1,220 11.4 330 3.7 8.0 1.0 313 22.1 0.2 195 6.43 25.8 Background Data Set Range (Bedrock Flow Zone) 0.11-1.25 0.071 j-2.3 23-857 0.01j-1.8 25.9j-49.1j 0.054j-1.9 1.2-4 0.012j-11.8 0.23j-31 0.026j-3.9 16-1530 3.8-11 2.8j-385 0.13j-6.2 0.33j-22.8 0. 17j-2.3 140-407 0.42j-23.9 0.016j-0.069 j 42-240 4.6E-05j- 1.5E-04 j 0.099j-26.6 Sample ID Flow Zone Analytical Results GWA-07S Shallow < 0.5 0.17 226 < 0.1 < 50 < 0.08 3.9 1.0 3.6 8.1 823 5.1 271 0.99 6.0 < 0.5 197 11 < 0.1 123 - 0.46 GWA-10S Shallow < 0.5 0.27 58 0.12 93 < 0.08 1.6 1.5 2.4 0.17 499 < 2.5 41 < 0.5 4.5 2.0 777 57 < 0.1 153 - 3.0 GWA-11S Shallow < 0.5 0.16 53 0.17 2746 0.24 6.0 0.21 0.65 0.26 305 2.1 18 0.88 1.5 21 1064 265 < 0.1 498 0.65 0.36 GWA-13S Shallow < 0.5 0.12 89 < 0.1 < 50 < 0.08 3.2 0.88 1.5 0.16 136 1.7 42 < 0.5 3.0 < 0.5 8.2 1.9 < 0.1 38 - 0.35 GWA-14S Shallow < 0.5 0.19 37 < 0.1 < 50 < 0.08 1.2 0.37 0.73 0.20 157 1.5 54 1.0 0.56 < 0.5 14 < 1 < 0.1 27 - < 0.3 GWA-15S Shallow < 0.5 0.13 154 0.16 1660 0.29 155 0.16 0.70 1.6 397 5.8 698 < 0.5 2.0 6.3 1687 87 < 0.1 488 2.4 0.36 ILF-01S Shallow < 0.5 0.22 87 < 0.1 26 < 0.08 30 0.09 0.74 1.4 250 5.6 408 4.3 4.5 0.68 632 48 < 0.1 209 1.4 1.1 ILF-02S Shallow 0.30 0.08 58 < 0.1 < 50 < 0.08 1.8 0.45 1.9 0.33 74 1.5 51 0.36 2.9 < 0.5 73 1.0 < 0.1 96 0.13 0.91 MS-08 Shallow < 0.5 0.11 38 0.14 < 50 < 0.08 1.1 3.1 5.2 0.33 801 1.3 9.3 < 0.5 2.0 < 0.5 94 < 1 < 0.1 54 - 4.9 MS-09 Shallow 0.18 0.15 40 2.8 < 50 - 1.2 - 2.2 3.1 185 - 37 - 3.2 - - 0.32 0.08 69 - 2.7 MS-11 Shallow < 0.5 0.10 83 < 0.1 < 50 < 0.08 4.4 0.47 2.8 0.28 372 0.74 16 < 0.5 1.5 < 0.5 80 1.1 < 0.1 42 - 0.41 MS-12 Shallow - - 74 - < 50 - 3.2 - 0.90 1.2 117 - 18 - 0.75 - - 0.5 0.08 32 - 0.62 MS-13 Shallow < 0.5 0.09 97 0.27 < 50 < 0.08 2.5 0.22 0.67 0.13 < 50 0.94 12 < 0.5 0.66 < 0.5 376 < 1 < 0.1 45 - 0.62 MS-14 Shallow - 0.22 47 - < 50 - 1.0 - 0.44 - 60 - < 5 - 0.99 - - 0.1 - 65 - 2.4 MS-15 Shallow 0.39 0.15 105 - < 50 - 2.2 - 17 0.40 129 - 6.5 - 2.5 0.60 - 0.99 - 103 - 6.6 MS-16 Shallow - 0.16 96 - < 50 - 1.5 - 3.0 0.40 297 - 8.4 - 1.5 - - 0.3 - 86 - 4.1 MW-01 Shallow < 0.5 0.13 387 0.19 200 0.16 159 3.6 4.4 0.18 269 2.2 39 < 0.5 2.3 0.98 2608 15 < 0.1 399 - 1.6 MW-02 Shallow < 0.5 0.18 49 0.15 3036 0.09 4.8 0.10 < 0.5 < 0.1 < 50 1.4 15 < 0.5 0.4 28 1663 152 < 0.1 295 - 1.0 MW-03 Shallow < 0.5 < 0.1 270 0.58 < 50 < 0.08 9.2 1.0 1.9 8.7 141 1.5 48 < 0.5 2.1 < 0.5 59 < 1 < 0.1 55 - 0.60 MW-05 Shallow < 0.5 0.25 57 0.35 < 50 < 0.08 2.4 1 0.27 1.2 0.16 623 0.79 15 0.65 1.2 < 0.5 139 1.0 < 0.1 61 - 0.72 MW-065 Shallow < 0.5 0.21 58 0.34 405 0.16 14 0.09 0.73 27 106 < 2.5 1055 < 0.5 1.9 0.56 21 23 0.11 94 1.7 < 0.3 MW-07 (OB-03) Shallow < 0.5 0.21 37 0.06 < 50 < 0.08 1.7 0.22 14 0.16 103 - 7.8 0.44 8.0 < 0.5 83 < 1 < 0.1 63 - 0.83 MW-075 Shallow < 0.5 3.0 109 1.1 4250 0.15 191 0.03 4.4 42 86 3.1 4382 0.50 3.7 1.6 396 93 0.45 475 1.6 < 0.3 MW-08S Shallow < 0.5 0.22 144 < 0.1 238 < 0.08 1.9 0.06 < 0.5 1.2 333 < 2.5 3058 2.2 1.5 1.3 1705 37 < 0.1 539 1.1 0.36 MW-095 Shallow < 0.5 < 0.1 254 < 0.1 < 50 < 0.08 14 0.42 0.66 < 0.1 < 50 < 2.5 12 < 0.5 < 0.5 0.51 1105 86 < 0.1 444 0.71 1.8 MW-10S Shallow < 0.5 < 0.1 43 < 0.1 < 50 < 0.08 1.0 0.15 < 0.5 0.11 55 0.86 7.7 < 0.5 1.3 < 0.5 < 5 < 1 < 0.1 28 0.85 < 0.3 MW-115 Shallow < 0.5 0.14 61 < 0.1 < 50 < 0.08 1 2.8 5.7 5.8 < 0.1 80 < 0.5 5.2 < 0.5 < 0.5 < 0.5 83 < 1 < 0.1 50 - 2.1 MW-12S Shallow < 0.5 < 0.1 52 < 0.1 < 50 < 0.08 1.5 0.52 0.66 1.2 122 0.71 17 < 0.5 1.3 < 0.5 33 < 1 < 0.1 31 - 0.41 MW-135 Shallow < 0.5 0.12 36 < 0.1 < 50 < 0.08 4.0 0.62 1.1 0.16 534 1.5 8.9 0.59 < 0.5 < 0.5 53 1.3 < 0.1 93 - 4.1 MW-14S Shallow < 0.5 < 0.1 35 0.67 2490 0.13 107 0.64 3.7 4.8 871 2.3 51 0.54 50 6.6 2350 217 < 0.1 563 1.1 0.77 OB-01 (Ash Basin) Shallow < 0.5 < 0.1 40 0.07 < 50 < 0.08 1.7 0.18 1.9 0.73 198 0.51 25 < 0.5 1.3 < 0.5 19 < 1 < 0.1 27 - < 0.3 -01 (Dry Ash Landfi Shallow < 0.5 0.18 1080 0.17 28SO 0.22 252 1.1 30 2.5 281 1.4 39 6.2 64 0.55 3275 11 < 0.1 593 - 1.4 PVSF-01S Shallow < 0.5 0.20 37 < 0.1 < 50 < 0.08 2.0 0.08 1.8 0.80 266 4.1 141 4.7 3.9 < 0.5 220 2.2 < 0.1 87 0.28 1.6 PVSF-02S Shallow < 0.5 1.1 62 0.81 3507 1.1 8.9 0.05 0.60 21 1737 - 22400 0.20 4.9 3.2 382 495 < 0.1 729 0.86 0.96 PVSF-03S Shallow < 0.5 0.44 107 1.4 7487 0.33 1 6.2 1 0.76 1.3 133 < 50 4.6 600 0.79 25 17 13 174 < 0.1 418 1 0.95 0.47 Deep Flow Zone AB-01D Deep < 0.5 0.19 431 < 0.1 1257 < 0.08 222 0.03 0.83 23 703 20 26 < 0.5 1.4 < 0.5 2615 40 < 0.1 606 2.1 1.1 AB-02D Deep < 0.5 0.21 28 < 0.1 399 < 0.08 4.9 0.22 0.83 0.43 338 7.7 43 < 0.5 0.65 < 0.5 681 171 < 0.1 380 3.3 0.41 AB-04D Deep < 0.5 0.18 72 < 0.1 360 < 0.08 8.4 0.03 < 0.5 0.35 1330 12 55 < 0.5 2.2 < 0.5 239 34 < 0.1 136 - < 0.3 AB-05D Deep < 0.5 0.88 101 < 0.1 < 50 < 0.08 2.8 0.03 < 0.5 7.3 755 1s 869 < 0.5 10 < 0.5 2662 109 < 0.1 319 0.8 0.63 AB-07D Deep < 0.5 0.85 142 < 0.1 < 50 < 0.08 2.2 1.0 1.3 0.17 129 10 21 < 0.5 3.0 < 0.5 468 < 1 < 0.1 114 - 6.7 AB-14D Deep < 0.5 0.17 169 < 0.1 442 < 0.08 1.9 2.1 1.5 < 0.1 52 3.0 5.4 0.62 0.70 0.77 524 55 < 0.1 161 - 1.2 AB-18DU Deep < 0.5 2.8 91 < 0.1 < 50 < 0.08 1.9 < 0.025 0.48 4.8 19100 1.4 1820 1.2 0.67 < 0.5 141 1.1 < 0.1 122 1.1 0.62 AB-21D Deep < 0.5 0.15 181 < 0.1 < 50 < 0.08 12 < 0.025 1.0 0.72 loss 13 88 1.3 3.7 < 0.5 512 17 < 0.1 177 - 0.61 AL-01D Deep < 0.5 0.12 879 < 0.1 3148 < 0.08 265 0.05 1.7 0.26 96 12 22 < 0.5 3.0 < 0.5 5537 16 < 0.1 661 10 0.81 AL-02D Deep < 0.5 0.23 44 < 0.1 11633 < 0.08 2.4 0.57 1.7 3.1 252 31 437 2.0 18 94 2770 916 < 0.1 1587 - 1.0 AL-03D Deep 0.39 0.20 67 < 0.1 5297 < 0.08 2.9 0.09 2.3 0.33 218 17 46 0.98 3.4 52 2875 452 < 0.1 888 - 0.59 AL-04D Deep < 0.5 0.26 87 < 0.1 16242 0.09 2.8 0.67 2.8 0.65 440 123 60 1.7 8.8 10 4544 594 < 0.1 1072 - 3.7 CCR-01D Deep < 0.5 0.45 51 < 0.1 < 50 < 0.08 1.6 0.06 < 0.5 0.09 < 50 3.1 29 0.41 0.51 < 0.5 670 4.0 < 0.1 131 0.64 13 CCR-02D Deep < 0.5 0.10 33 0.10 140 < 0.08 5.0 0.98 0.89 < 0.1 < 50 1.8 32 < 0.5 < 0.5 < 0.5 116 5.0 < 0.1 68 0.75 1.5 CCR-03D Deep < 0.5 0.10 39 < 0.1 < 50 < 0.08 1.1 0.09 < 0.5 < 0.1 41 7.7 1.6 0.26 - 0.56 556 94 < 0.1 234 0.76 2.9 CCR-04D Deep < 0.5 0.10 51 < 0.1 16 < 0.08 0.8 - 0.66 1.3 - 21 - 0.49 - < 0.5 - 73 < 0.1 227 0.84 - CCR-05D Deep 1.3 0.20 130 < 0.1 8.0 < 0.08 2.9 - 0.54 0.61 - 62 - 1 0.81 - < 0.5 - 34 0.13 232 3.0 - CCR-09DA Deep 0.42 0.58 83 < 0.1 26 < 0.08 81 0.04 2.9 0.19 144 21 16 1.5 1.7 < 0.5 776 20 < 0.1 284 2.9 0.78 CCR-11D Deep < 0.1 < 0.1 900 0.56 2917 1.3 270 - 3.0 4.7 - 6.3 - < 0.5 - < 0.5 - 14 0.27 215 6.4 - Page 2 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - FEBRUARY 2018 TO MAY 2019 CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium (VI) Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 10 1* 300 NE 50 NE 100 20 NE 250 0.2* 500 5^ 0.3* 2018 Background Threshold Values (Shallow Flow Zone)' 0.5 310 0.2 50 0.08 5.5 irr5.7 16.5 1.2 744 --- 75.3 9.9 1 0.1 140 3.0 2019 Background Threshold Values (Shallow Flow Zone)21 0.79 1 1 580 0.223 1 50 1.0 5.0 7.0 16.8 5.0 1095 14.8 155 1.0 19.6 1.0 210 1 11.3 0.2 152.4 5.33 13.0 Background Data Set Range (Shallow Flow Zone) 0.1 j - 1.12 0.043 j - 1.7 22.2 - 730 0.012 j - 0.61 3.3 - 56.7 0.052 j - 0. 101 0.92 - 5.4 0.076 j - 7.1 0.1 i - 39.2 0.041 j - 5.2 28 - 3440 0.19 i - 5.6 1.46 j - 390 0.076 j - 1.4 0.28 j - 21.9 0.092 - 0.72 9 - 223 0.0447 j - 12.8 0.015 j - 0.024 10 - 144 0.049 - 6.73 0.077 j - 15.4 2018 Background Threshold Values (Deep Flow Zone)' 127 0. 50 0.08 4.7 7.6 1.9 272 --- 141 665 17.7 0.1 183 2.8 2019 Background Threshold Values (Deep Flow Zone) 0.62 1.4 138 0.2 50 0.08 4.2 6.0 4.3 3.2 225 10.0 142 7.3 7.8 2.4 727 24.2 0.1 200 7.46 3.9 Background Data Set Range Dee Flow Zone 9 9( P ) 0.14'-1.3 J 0.088'-1.9 ] 15.1-146 0.012'-0.095' J J 2.3'-43' ] J 0.03'-0.054' J J 1.2-4.8 0.01 2.7 J- 0.15'-3.1 J 0.013'-3.3 ] 30.4'-310 ] 2.5-10.9 7.4-154 0.19 10.5 j- 0.13 7.9 j- 0.17j-2.9 J 81.4-732 2.3-35.4 0.018j-0.054 41-202 0.2587-11.14 0.74-4 2018 Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 3.0 7.2 1 253 0.1 216 5.7 2019 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1,220 11.4 330 3.7 8.0 1.0 313 22.1 0.2 195 6.43 25.8 Background Data Set Range (Bedrock Flow Zone) 0.11-1.25 0.071 j-2.3 23-857 0.01j-1.8 25.9j-49.1j 0.054j-1.9 1.2-4 0.012j-11.8 0.23j-31 0.026j-3.9 16-1530 3.8-11 2.8j-385 0.13j-6.2 0.33j-22.8 0. 17j-2.3 140-407 0.42j-23.9 0.016j-0.069 j 42-240 4.6E-05j- 1.5E-04 j 0.099j-26.6 Sample ID Flow Zone Analytical Results CCR-12D Deep < 0.5 0.07 58 < 0.1 12 < 0.08 3.0 - 0.63 0.05 - 1.9 - < 0.5 - < 0.5 - 7.6 < 0.1 116 0.97 - CCR-13D Deep < 0.5 < 0.1 299 < 0.1 202 < 0.08 165 < 0.025 < 0.5 < 0.1 < 50 10 18 < 0.5 < 0.5 < 0.5 2950 2.6 < 0.1 427 6.5 0.90 CCR-14D Deep < 0.5 < 0.1 532 < 0.1 2220 < 0.08 238 - 0.53 < 0.1 - 16 - < 0.5 - < 0.5 - 10 < 0.1 565 5.4 - CCR-15D Deep < 0.5 0.55 352 < 0.1 3.2 < 0.08 2.7 - 3.1 0.11 - 7.0 - 0.32 - 0.93 - 5.3 < 0.1 119 2.3 - CCR-16D Deep < 0.5 0.49 41 < 0.1 3.5 < 0.08 3.5 - 0.78 < 0.1 - 14 - 1.3 - 0.41 - 8.2 < 0.1 145 1.8 - CP-01D Deep 0.11 0.27 70 1.7 < 50 4.5 10 0.13 < 0.5 91 383 42 24200 2.9 61 1.5 1183 825 < 0.1 1337 1.8 1.3 CP-02D Deep 0.17 0.20 25 < 0.1 < 50 < 0.08 1.4 0.92 1.8 1.7 318 2.9 370 3.2 2.7 < 0.5 142 < 1 < 0.1 233 0.94 4.0 CP-03D Deep < 0.5 0.21 47 < 0.1 < 50 < 0.08 2.1 0.36 1.2 0.21 178 3.7 42 0.85 1.2 < 0.5 99 1.2 < 0.1 341 1.2 3.7 GP-01D Deep < 0.5 0.21 185 < 0.1 < 50 < 0.08 1.9 1.4 2.1 0.67 71 5.1 58 0.82 1.4 1.2 779 77 < 0.1 189 1.7 3.0 GP-02D Deep < 0.5 0.17 89 < 0.1 < 50 < 0.08 2.1 0.83 1.4 0.33 54 5.3 29 0.95 1.5 0.50 858 30 < 0.1 156 1.3 2.1 GP-03D Deep < 0.5 0.31 32 < 0.1 < 50 < 0.08 1.9 0.61 2.3 0.45 275 < 2.5 54 2.6 2.5 < 0.5 235 5.1 < 0.1 94 0.94 1.8 GWA-01D Deep < 0.5 0.26 50 < 0.1 < 50 < 0.08 2.3 < 0.025 0.98 0.38 305 18 48 11 4.1 < 0.5 886 214 < 0.1 434 2.2 0.73 GWA-03D Deep < 0.5 < 0.1 31 < 0.1 < 50 < 0.08 2.0 0.33 0.60 < 0.1 55 3.9 11 1 2.4 < 0.5 < 0.5 67 2.3 < 0.1 97 - 1.1 GWA-07D Deep < 0.5 0.19 355 < 0.1 < 50 < 0.08 2.6 1 6.0 5.8 0.19 106 7.5 6.2 0.63 4.5 < 0.5 189 8.9 < 0.1 135 - 4.5 GWA-SOD Deep < 0.5 0.15 64 0.10 < 50 < 0.08 1.3 < 0.025 0.42 0.28 699 9.1 14 0.88 1.1 < 0.5 1740 220 < 0.1 428 - 0.94 GWA-11D Deep < 0.5 0.12 102 < 0.1 1069 < 0.08 5.2 1.9 2.4 0.15 130 8.1 83 < 0.5 0.86 10 1664 112 < 0.1 273 1.5 2.1 GWA-13DA Deep 1.5 1.1 13 < 0.1 < 50 < 0.08 2.2 0.13 1.1 0.06 345 30 8.2 1.9 0.86 < 0.5 110 2.8 < 0.1 143 - 6.1 GWA-14D Deep 0.67 0.57 24 < 0.1 < 50 0.10 1.6 0.36 1.6 0.16 204 2.9 24 1.1 1.2 < 0.5 70 1.6 < 0.1 103 - 2.9 GWA-15D Deep < 0.5 0.16 94 < 0.1 66 0.09 39 < 0.025 0.64 1.4 1033 8.7 486 2.6 5.2 < 0.5 1025 108 < 0.1 334 11 0.84 ILF-01D Deep < 0.5 0.18 52 < 0.1 < 50 < 0.08 4.2 0.61 1.1 0.41 57 4.0 121 1.5 1.3 < 0.5 230 6.2 < 0.1 111 0.76 2.4 ILF-02D Deep < 0.5 0.09 22 < 0.1 < 50 < 0.08 2.6 0.33 1.4 1.4 74 4.0 17 0.61 2.2 < 0.5 77 1.3 < 0.1 97 0.70 2.4 MW-06D Deep < 0.5 < 0.1 369 < 0.1 175 0.16 143 0.09 1.1 0.22 117 3.1 8.2 < 0.5 3.0 < 0.5 1828 5.6 < 0.1 414 3.3 0.38 MW-07D Deep < 0.5 0.18 85 < 0.1 378 < 0.08 115 0.03 0.53 < 0.1 990 8.5 747 < 0.5 < 0.5 < 0.5 1485 74 < 0.1 490 5.9 < 0.3 MW-09D Deep < 0.5 < 0.1 87 < 0.1 468 0.13 6.6 0.03 < 0.5 1.4 51 5.1 989 < 0.5 4.6 < 0.5 1175 172 < 0.1 351 < 1.4 0.62 MW-lOD Deep < 0.5 < 0.1 18 < 0.1 < 50 < 0.08 1.3 0.42 0.59 < 0.1 63 2.1 < 5 < 0.5 < 0.5 < 0.5 99 3.8 < 0.1 72 < 0.49 2.9 MW-11D Deep < 0.5 0.20 57 < 0.1 < 50 < 0.08 1.9 8.4 8.8 < 0.1 < 50 3.5 < 5 < 0.5 0.59 < 0.5 94 < 1 < 0.1 66 - 14 MW-12D Deep < 0.5 0.13 19 < 0.1 51 < 0.08 < 1 0.45 0.66 0.37 147 3.2 7.0 0.76 0.94 < 0.5 170 4.5 < 0.1 73 - 1.0 MW-13D Deep < 0.5 < 0.1 48 < 0.1 < 50 < 0.08 4.4 0.99 1.5 < 0.1 < 50 2.4 < 5 0.65 0.54 < 0.5 69 < 1 < 0.1 89 - 4.9 MW-14D Deep < 0.5 0.11 35 0.34 2115 < 0.08 56 0.07 < 0.5 1.8 < 50 4.5 42 < 0.5 20 3.0 2128 160 < 0.1 423 0.53 < 0.3 PVSF-01D Deep < 0.5 0.24 74 < 0.1 < 50 < 0.08 1.8 0.18 0.61 0.35 64 2.9 1 35 1.1 1.6 < 0.5 269 3.4 < 0.1 103 1.2 2.7 PVSF-02D Deep < 0.5 0.19 48 0.36 4500 0.88 5.7 0.41 3.1 10 152 - 933 0.68 7.6 12 689 450#-< < 0.1 927 2.3 1.1 PVSF-03D Deep < 0.5 0.22 11 < 0.1 < 50 < 0.08 3.8 0.32 2.1 0.28 239 6.2 65 1.4 1.4 0.71 121 17 0.1 135 0.74 2.3 Bedrock Flow Zone AB-01BR Bedrock < 0.5 0.23 79 < 0.1 2818 < 0.08 240 0.03 < 0.5 2.5 8090 21 595 < 0.5 1.0 < 0.5 2217 54 < 0.1 677 17 0.35 AB-01BRL Bedrock < 0.5 0.15 289 < 0.1 2213 < 0.08 282 < 0.025 0.67 < 0.1 7961 16 927 0.68 0.66 < 0.5 2054 39 < 0.1 799 16 0.35 AB-OIBRLL Bedrock < 0.5 0.15 270 < 0.1 2022 < 0.08 288 < 0.025 0.66 0.12 6938 13 1398 0.17 0.84 < 0.5 1783 40 < 0.1 752 4.8 < 0.3 AB-01BRLLL Bedrock < 0.5 1.5 80 < 0.1 60 < 0.08 5.8 < 0.025 < 0.5 0.17 122 8.2 304 0.73 0.66 < 0.5 1090 85 < 0.1 340 5.6 0.42 AB-02BR Bedrock < 0.5 0.42 5 < 0.1 < 50 < 0.08 2.6 < 0.025 < 0.5 0.16 < 50 3.9 24 0.94 < 0.5 < 0.5 1140 101 < 0.1 353 3.9 < 0.3 AB-03D Bedrock < 0.5 0.14 115 < 0.1 165 < 0.08 4.5 0.04 1.0 0.13 124 12 48 < 0.5 1.4 < 0.5 1246 95 < 0.1 277 - 2.4 AB-05BR Bedrock < 0.5 0.36 83 < 0.1 < 50 < 0.08 1.8 0.16 1.3 0.98 294 48 127 < 0.5 13 < 0.5 3648 281 < 0.1 537 3.0 < 0.3 AB-06BRA Bedrock 0.12 179 73 < 0.1 512 < 0.08 2.5 0.03 < 0.5 < 0.1 214 59 71 5.7 < 0.5 < 0.5 3273 109 < 0.1 376 - 0.46 AB-06BRL Bedrock < 0.5 0.51 30 < 0.1 < 50 < 0.08 2.4 0.03 < 0.5 < 0.1 256 3.0 58 4.4 0.77 < 0.5 6013 281 < 0.1 551 1.5 < 0.3 AB-06D Bedrock < 0.5 1.9 92 0.60 5325 < 0.08 3.6 < 0.025 < 0.5 1.9 5473 15 457 < 0.5 50 < 0.5 4140 43 < 0.1 326 - < 0.3 AB-08D Bedrock < 0.5 0.35 51 < 0.1 < 50 < 0.08 2.4 < 0.025 < 0.5 0.14 89 7.0 329 2.1 < 0.5 < 0.5 2248 76 < 0.1 277 - < 0.3 AB-09BR Bedrock < 0.5 0.63 198 < 0.1 < 50 < 0.08 1.4 0.04 < 0.5 0.14 712 25 92 4.8 1.5 < 0.5 259 16 < 0.1 187 - 0.33 AB-09D Bedrock < 0.5 1 0.41 255 < 0.1 < 50 < 0.08 1.7 < 0.025 0.60 2.4 1006 15 51 2.6 23 < 0.5 228 8.2 < 0.1 147 - < 0.3 AB-IOBR Bedrock < 0.5 0.37 217 < 0.1 276 < 0.08 2.9 < 0.025 < 0.5 0.13 251 22 27 0.62 1.8 < 0.5 4668 20 < 0.1 377 - < 0.3 AB-IOBRL Bedrock < 0.5 6.7 33 < 0.1 < 50 < 0.08 6.2 0.04 < 0.5 < 0.1 64 2.6 39 2.2 < 0.5 < 0.5 3773 89 < 0.1 341 8.2 0.42 AB-lOD Bedrock < 0.5 0.74 426 < 0.1 1430 < 0.08 5.2 < 0.025 < 0.5 30 4338 7.7 4197 1.5 25 < 0.5 2857 9.2 < 0.1 332 - 0.66 AB-111) Bedrock < 0.5 0.15 17 < 0.1 57 < 0.08 1.7 0.08 < 0.5 < 0.1 118 5.3 5.3 0.68 < 0.5 < 0.5 1198 3.2 < 0.1 106 - 0.60 AB-12BR Bedrock < 0.5 0.84 28 < 0.1 51 < 0.08 1.4 0.03 < 0.5 < 0.1 115 5.8 29 2.0 0.62 < 0.5 2756 165 < 0.1 395 8.2 < 0.3 AB-12D Bedrock 0.57 2.8 49 < 0.1 1118 < 0.08 127 0.18 2.2 < 0.1 108 6.1 104 0.60 2.9 < 0.5 10332 174 < 0.1 689 6.4 < 0.3 AB-13D Bedrock < 0..9 0.56 218 < 0.1 < 50 1 0.08 1 1.8 0.05 1.2 2.1 952 8.1 227 1.4 0.74 < 0.5 691 14 < 0.1 222 - < 0.3 AB-15BR Bedrock < 0.5 0.11 106 < 0.1 < 50 < 0.08 2.2 < 0.025 < 0.5 < 0.1 2412 1 4.4 270 0.95 0.68 1 0.55 1064 69 < 0.1 286 - 0.31 AB-15D Bedrock < 0.5 0.11 253 < 0.1 < 50 < 0.08 2.6 0.03 0.55 1 < 0.1 1 2612 5.1 1 260 1 0.75 0.53 1 < 0.5 1 652 1 34 1 < 0.1 1 271 1 < 0.3 Page 3 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - FEBRUARY 2018 TO MAY 2019 CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium (VI) Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 10 1* 300 NE 50 NE 100 20 NE 250 0.2* 500 5^ 0.3* 2018 Background Threshold Values (Shallow Flow Zone), 0.5 310 0.2 50 0.08 5.5 irr5.7 16.5 1.2 744 --- 75.3 9.9 1 0.1 140 3.0 2019 Background Threshold Values (Shallow Flow Zone)21 0.79 1 1 580 0.223 1 50 1.0 5.0 7.0 16.8 5.0 1095 14.8 155 1.0 19.6 1.0 210 1 11.3 0.2 152.4 5.33 13.0 Background Data Set Range (Shallow Flow Zone) 0.1 j - 1.12 0.043 j - 1.7 22.2 - 730 0.012 j - 0.61 3.3 - 56.7 0.052 j - 0.101 0.92 - 5.4 0.076 j - 7.1 0.1 j - 39.2 0.041 j - 5.2 28 - 3440 0.19 j - 5.6 1.46 j - 390 0.076 j - 1.4 0.28 j - 21.9 0.092 - 0.72 9 - 223 0.0447 j - 12.8 0.015 j - 0.024 10 - 144 0.049 - 6.73 0.077 j - 15.4 2018 Background Threshold Values (Deep Flow Zone)' 127 0. 50 0.08 4.7 7.6 1.9 272 --- 141 665 17.7 0.1 183 2.8 2019 Background Threshold Values (Deep Flow Zone) 0.62 1.4 138 0.2 50 0.08 4.2 6.0 4.3 3.2 225 10.0 142 7.3 7.8 2.4 727 24.2 0.1 200 7.46 3.9 Background Data Set Range Dee Flow Zone 9 9( P ) 0.14'-1.3 J 0.088'-1.9 ] 15.1-146 0.012'-0.095' J J 2.3'-43' ] J 0.03'-0.054' J J 1.2-4.8 0.01 2.7 J- 0.15'-3.1 J 0.013'-3.3 ] 30.4'-310 ] 2.5-10.9 7.4-154 0.19 10.5 j- 0.13 7.9 j- 0.17j-2.9 J 81.4-732 2.3-35.4 0.018j-0.054 41-202 0.2587-11.14 0.74-4 2018 Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 3.0 7.2 1 253 0.1 216 5.7 2019 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1,220 11.4 330 3.7 8.0 1.0 313 22.1 0.2 195 6.43 25.8 Background Data Set Range (Bedrock Flow Zone) 0.11-1.25 0.071 j-2.3 23-857 0.01j-1.8 25.9j-49.1j 0.054j-1.9 1.2-4 0.012j-11.8 0.23j-31 0.026j-3.9 16-1530 3.8-11 2.8j-385 0.13j-6.2 0.33j-22.8 0. 17j-2.3 140-407 0.42j-23.9 0.016j-0.069 j 42-240 4.6E-05j- 1.5E-04 j 0.099j-26.6 Sample ID Flow Zone Analytical Results AB-16D Bedrock < 0.5 0.86 183 < 0.1 < 50 < 0.08 3.4 0.03 0.53 0.25 1390 23 201 1.0 1.8 < 0.5 0 404 25 < 0.1 199 - < 0.3 AB-17D Bedrock < 0.5 0.16 26 < 0.1 < 50 < 0.08 1.2 1.0 1.4 0.11 < 50 5.0 < 5 < 0.5 0.98 < 0.5 107 < 1 < 0.1 89 - 4.5 AB-18D Bedrock < 0.5 0.34 37 < 0.1 < 50 < 0.08 1.7 0.17 0.56 0.10 62 4.1 76 1.0 2.0 < 0.5 185 4.8 < 0.1 99 - 2.8 AB-20D Bedrock < 0.5 0.57 56 < 0.1 80 < 0.08 1.9 0.04 1.3 < 0.1 262 1.4 10 14 1.5 < 0.5 496 19 < 0.1 132 - 0.76 AL-01BR Bedrock < 0.5 < 0.1 368 < 0.1 622 < 0.08 173 0.10 2.9 0.16 81 18 9.7 0.60 7.2 < 0.5 3230 7.8 < 0.1 492 11 0.84 AL-01BRL Bedrock < 0.5 1.4 91 < 0.1 < 50 < 0.08 3.8 < 0.025 < 0.5 0.18 165 9.9 365 5.7 0.69 < 0.5 1400 224 < 0.1 474 33 0.80 AL-02BR Bedrock 0.27 0.40 138 < 0.1 4308 < 0.08 < 1 0.45 1.9 0.75 101 17 41 4.8 6.7 20 3227 254 < 0.1 551 - 2.8 AL-02BRL Bedrock < 0.5 0.20 108 < 0.1 1401 < 0.08 1.1 0.28 1.7 0.05 < 50 43 15 1.4 0.63 5.5 1595 203 < 0.1 439 < 0.567 0.29 AL-02BRLL Bedrock < 0.5 0.25 76 < 0.1 10084 < 0.08 4.5 0.03 0.80 0.12 321 60 414 1.2 1.2 0.88 3710 520 < 0.1 1013 5.8 < 0.3 AL-02BRLLL Bedrock < 0.5 6.1 171 < 0.1 < 50 < 0.08 21 0.03 0.87 0.18 437 3.6 176 1.6 0.86 < 0.5 1023 129 < 0.1 402 4.0 0.83 AL-03BR Bedrock < 0.5 0.52 114 < 0.1 1114 < 0.08 2.1 0.07 2.4 0.09 < 50 119 35 4.0 2.2 7.3 1160 178 < 0.1 422 - < 0.3 AL-04BR Bedrock < 0.5 0.14 96 0.11 8992 0.08 1.7 0.47 1.9 0.15 137 33 6.7 0.66 5.1 6.4 2842 225 < 0.1 456 - 3.2 AL-04BRL Bedrock < 0.5 0.34 124 < 0.1 < 50 < 0.08 2.3 < 0.025 0.82 < 0.1 1 582 27 56 1.7 0.54 < 0.5 413 5.6 < 0.1 134 - 0.38 GWA-01BR Bedrock < 0.5 0.11 38 < 0.1 < 50 < 0.08 3.0 2.4 2.8 0.82 72 6.2 < 5 < 0.5 0.57 < 0.5 276 50 < 0.1 159 1.2 4.1 GWA-09BR Bedrock < 0.5 < 0.1 17 < 0.1 < 50 < 0.08 4.3 0.64 0.84 < 0.1 < 50 3.8 < 5 < 0.5 0.55 < 0.5 52 < 1 < 0.1 98 - 3.1 GWA-11BR Bedrock 0.73 0.13 52 < 0.1 < 50 < 0.08 3.7 < 0.025 1.9 < 0.1 223 5.4 8.0 1.1 2.3 < 0.5 S66 48 < 0.1 201 1.3 2.3 GWA-12D Bedrock < 0.5 0.35 42 < 0.1 < 50 < 0.08 3.4 < 0.025 < 0.5 0.10 72 - 9.2 12 0.76 < 0.5 285 11 < 0.1 150 < 0.601 0.32 ILF-01BR Bedrock 0.48 0.34 8 < 0.1 < 50 < 0.08 2.7 0.21 1.8 16 199 4.7 39 5.9 3.1 < 0.5 160 4.7 < 0.1 126 0.53 2.4 MW-08D Bedrock < 0.5 0.11 14 0.11 277 < 0.08 8.5 < 0.025 < 0.5 0.31 832 6.6 111 < 0.5 < 0.5 < 0.5 1693 97 < 0.1 383 2.3 < 0.3 MW-14BR Bedrock < 0.5 0.13 43 < 0.1 144 < 0.08 53 0.41 3.0 0.17 90 12 5.7 0.69 4.2 1.2 819 9.8 < 0.1 158 3.0 3.2 Bedrock < 0.5 0.47 227 < 0.1 < 50 < 0.08 2.2 < 0.025 0.62 < 0.1 90 5.1 6.8 1.4 0.58 < 0.5 280 10 < 0.1 209 5.6 6.3 Bedrock 0.53 0.47 96 < 0.1 < 50 < 0.0LPffVSF-01BR Bedrock < 0.5 0.16 54 < 0.1 2900 < 0.08 Bedrock 0.25 0.74 40 < 0.1 < 50 < 0.08 4.9 0.04 2.8 0.46 105 < 2.5 26 14 4.6 < 0.5 619 14 < 0.1 196 0.64 0.86 Notes: 1 - Background threshold values were calculated using data from background groundwater samples collected September 2015 to October 2017. 2 - Background threshold values were calculated using data from background groundwater samples collected February 2010 to December 2018. Statistical mean calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. For wells with datasets containing fewer than four valid results, the most recent valid sample data was used. Means were calculated for wells with four or more valid sample results. Sample results were excluded from calculations: 1) if turbidity >10 NTU (for COIs other than boron) 2) for unusable data (RO qualified) 3) if a result was non -detect at a reporting limit (RL) greater than the normal laboratory RL Bold text - greatest comparative value O - bold highlighted concentration indicates value is greater than the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202 Standard and IMAC is April 1, 2013) O - bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard = - highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. < - concentration not detected at or above the adjusted reporting limit. - - no available data to conduct mean analysis NE - not established mg/L - milligrams per liter pg/L - micrograms per liter Prepared by: WCG Checked by: ECW Page 4 of 4 TABLE 6-6 COI MANAGEMENT MATRIX CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Constituent Standards and Values - 02L Criterion Lines of Evidence (LOE) - 02L Criterion Rationale for Exclusion/Inclusion for Corrective Action Shallow 0.4 1 0.043 - 5 3.0 0.3 0 - 0 0 0 N No means exceed comparative criteria Arsenic pg/L 10 Transition Zone 0.6 1 0.088 - 1.9 0.1 - 6.35 0.6 0.1 0 - Y 0 0 0 N Variable No means exceed comparative criteria Bedrock 0.6 1 0.071 - 2.3 0.2 0.0 0 - 0 0 o N No means exceed comparative criteria Shallow 310 580 22.2 - 730 254 0.4 0 - 0 0 0 N No means exceed comparative criteria Barium pg/L 700 Transition Zone 127 138 15.1 - 146 11 - 840 879 1.3 1 AL-1D y 4 1 1 y Variable Single location with detection of barium above 02L standard. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria Bedrock 435 840 23 - 857 368 0.4 0 0 0 0 N No means exceed comparative criteria AB -IS, AL -IS, CCR-9S, Shallow 50 5o 3.3 - 56.7 4,250 6.1 7 GWA-11S, GWA-15S, MW- 12 12 11 Y Exceedances depict a plume -like distribution likely attributed to the ash basin 7 MW-14 Transition Zone 50 5o 2.3- 50 3,148.33 4.5 4 AB-1D, ZIW GWA-11D, MW-14D 9 9 7 y Exceedances depict a plume -like distribution likely attributed to the ash basin Boron pg/L 700 49.1 - 176.8 Y Conservative Bedrock 50 50 25.9 - 50 2,818.33 4.0 3 AB-1BR, AB-1BRL, AB- 1BRLL 6 6 5 Y Single location (three intervals) with detection of boron about 02L. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria Shallow 0.08 1 0.052 - 1 0.7 0.4 0 - 0 0 0 N No means exceed comparative criteria Transition Zone 0.08 0.08 0.03 - 0.08 0.2 0.1 0 - 3 0 0 N No means exceed comparative criteria Cadmium pg/L 2 0.08 - 1 Y Variable Bedrock 0.08 1 0.054 - 1.9 < 0.08 0 0 0 0 0 N No means exceed comparative criteria Shallow 5.5 5 0.92 - 5.4 191 0.8 0 - 11 11 o N No means exceed comparative criteria Chloride mg/L 250 Transition Zone 4.7 4 1.2 - 4.8 3 - 250 265 1.1 1 AL-1D Y 10 8 1 y Conservative Single location with detection of chloride above 02L. Does not exhibit a discernible plume; however, other CCR- related constituents present above comparative criteria Bedrock 4.5 4 1.2-4 288 1.2 2 AB-1BRL, AB-1BRLL 6 6 2 y Single location (two intervals) with detection of chloride about 02L. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria Shallow 16.5 17 0.23 - 39.2 4 0.3 0 - 0 0 0 N No means exceed comparative criteria Chromium (Total) pg/L 10 Transition Zone 7.6 4 0.15 - 3.1 1 - 26 6 0.6 0 - y 1 0 0 N Nan -Conservative No means exceed comparative criteria Bedrock 8.3 11 0.23 - 31 3 0.3 0 - 0 0 0 N No means exceed comparative criteria Shallow 744 1,095 26.9 - 3440 1,298 1.2 1 AB-2S 0 0 0 Y Single location with detection of iron above 02L. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria Transition Zone 272 225 30.4 - 310 1,032.50 3.4 5 AB-11), AB-21), GWA-30D, GWA-15D MW-7D 5 0 o Y Exceedances depict aplume-like distribution likely attributed to the ash basin Iron pg/L 300 56.3 - 37500 y Variable Bedrock 792 1,220 10 - 1530 8,090 6.6 3 AB-1BR, AB-1BRL, AB- 1BRLL 3 3 0 y Single location (three intervals) with detection of iron about 02L. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria AB-1S, AB-2S, AL -IS, CCR Shallow 75.3 155 2.2 - 390 4,381.67 28.3 9 9S, GWA-7S, GWA-15S, a 8 0 y Exceedances depict a plume -like distribution likely attributed to the ash basin MW-6S, MW-7S, MW-8S Manganese pg/L 5o 7 -9170 y Variable Transition Zone 141 142 2.8 - 154 989 7.0 3 GWA-15D, MW-7D, MW-9D 3 3 0 y Exceedances depict a plume -like distribution likely attributed to the ash basin Bedrock 26.6 330 2.7 - 385 1,397.50 4.2 3 AB-IBR, AB-IBRL, AB- 3 3 0 Y Exceedances depict a plume -like distribution likely attributed to the ash basin Shallow 9.9 20 0.28 - 21.9 5o 0.5 0 - 1 1 1 N No means exceed comparative criteria Transition Zone 7.5 8 0.13 - 7.9 20 0.2 0 - 1 0 o N No means exceed comparative criteria Nickel pg/L 100 1.98 - 20 Y Variable Bedrock 7.2 8 0.33 - 22.8 7 0.1 0 0 0 0 N No means exceed comparative criteria Selenium pg/L 20 Shallow 0.5 1 0.092 - 10 0.5 - 2 21 1.1 1 GWA-11S y 1 1 1 y Variable Single location with detection of selenium above 02L. Does not exhibit a discernible plume; however, other CCR- related constituents resent above comparative criteria Transition Zone 0.5 2.4 0.17 - 2.9 10 0.5 0 - 2 0 2 N No means exceed comparative criteria Bedrock 0.5 1 0.17 - 2.3 1 0.1 0 0 0 0 N No means exceed comparative criteria Sulfate mg/L 250 Shallow 4.2 11 0.0589 - 12.8 1.2 - 510 265 1.1 1 GWA-11S y 13 12 0 y Conservative Single location with detection of sulfate above 02L. Does not exhibit a discernible plume; however, other CCR- related constituents present above comparative criteria Transition Zone 17.7 24 2.3 - 35.4 220 0.9 0 - 10 10 o N No means exceed comparative criteria Bedrock 18.4 22 0.42 - 23.9 97 0.4 0 6 6 0 N No means exceed comparative criteria Shallow 140 152 10- 144 563 1.1 4 AB-1S, AL-IS5 W-8S, MW 12 11 0 Y Exceedances depict a plume -like distribution likely attributed to the ash basin Transition Zone 183 200 41 - 202 661 1.3 2 AB-113, AL -SD 1s 12 o Y Exceedances depict a plume -like distribution likely attributed to the ash basin Total Dissolved Solids mg/L Soo 50- 1200 Y Conservative Bedrock 216 195 42 - 240 799 1.6 3 AB-1BR, AB-1BRL, AB- 1BRLL 5 5 o Y Exceedances depict a plume -like distribution likely attributed to the ash basin Constituent Standards and Values - IMAC Criterion Lines of Evidence (LOE) - IMAC Criterion Rationale for Exclusion - IMAC Criterion Shallow 0.5 1 0.1 - 1.12 0.5 0.5 0 - 0 0 0 N No means exceed comparative criteria Antimony Ng/L 1 Transition Zone 0.5 1 0.11 - 1.3 0.5 - 4.2 1.325 1.3 1 CCR-5D y 1 0 0 y Conservative Single location with detection of antimony above IMAC. Does not exhibit a discernible plume; however, other CCR- related constituents present above comparative criteria Bedrock 0.5 1 0.11 - 2.5 0.726 0.7 0 0 0 o N No means exceed comparative criteria Beryllium pg/L 4 Shallow 0.2 0.2 0.012 - 0.61 0.053 - 1 4.6 1.2 1 AL -IS y 7 2 2 y Non -Conservative Single location with detection of beryllium above IMAC. Does not exhibit a discernible plume; however, other CCR- related constituents present above comparative criteria Transition Zone 0.1 0.2 0.012 - 0.2 0.34 0.1 0 - 1 0 0 N No means exceed comparative criteria Bedrock 0.2 0.2 0.01 - 1.8 0.1 0.0 0 0 0 0 N No means exceed comparative criteria Page 1 of 2 TABLE 6-6 COI MANAGEMENT MATRIX CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC r AB-15, AB-25, AL-15, CCR Shallow 1.2 5 0.041 - 5.2 116.4 23.3 8 4S, CCR-9S, GWA-7S, MW- 8 8 2 Y Exceedances depict a plume -like distribution likely attributed to the ash basin Cobalt pg/L 1 0.2 - 88.85 65 MW-75 v Variable Y Transition Zone 1.9 3.2 0.013 - 3.3 23.1 7.2 1 AB-1D 1 1 0 Single location with detection of cobalt above IMAC. Does not exhibit a discernible plume; however, other CCR- related constituents resent above com arative criteria Bedrock 2.8 2.6 0.026 - 3.9 2.5 0.9 0 - o o o No means exceed comparative criteria N Thallium pg/L 0.2 Shallow 0.1 0.2 0.015 - 0.2 0.1 -0.2 0.7 3.5 4 AB-1S, CCR-4S, CCR-9S, MW-7S y 4 4 4 y N Variable Four locations with detection of thallium above 02L. Two locations depict a plume -like distribution attributed to the ash basin Transition Zone 0.1 0.1 0.018 - 0.1 0.1 0.7 0 - 1 o o No means exceed comparative criteria Bedrock 0.1 0.2 0.015 - 0.2 < 0.1 0 0 - 0 0 0 No means exceed comparative criteria N Shallow 3 5 (-0.112) - 6.73 3.1 0.6 0 - o o o N No means exceed comparative criteria Total Radium pCi/L 5^ 0.825 - 35 N v Variable Transition Zone 2.8 7 0.2587 - 11.14 10.8 1.5 2 AL -SD, GWA-15D o o o Two locations with detection of total radium above IMAC. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria Bedrock 5.7 6 0.573 - 7.43 16.7 2.8 3 AB-SBR, AB-SBRL, AL-1BR 3 2 0 Single location (three intervals) with detection of chloride about IMAC. Does not exhibit a discernible plume; however other CCR-related constituents resent above com arative criteria Y Shallow 5.6 13 0.093 - 15.4 3.0 0.2 0 - o o o N No means exceed comparative criteria Single location with detection of vanadium above IMAC. Does not exhibit a discernible plume. Concentrations are Vanadium pg/L 0.3 Transition Zone 3.8 4 0.74 - 4 0.657 - 26 4.5 1.1 1 GWA-7D Y 1 0 0 N Nan -Conservative within range of Piedmont background datasets. Groundwater flow direction derived from water elevations collected over 30 monitoring events and velocity vectors derived from groundwater flow and transport modeling simultations indicate this location is beyond the downgradient flow path from the source area. N Bedrock 16 26 0.11 - 26.6 4.1 0.2 0 - o 0 o No means exceed comparative criteria Constituent Standards and Values - Background Criterion Lines of Evidence (LOE) - Background Criterion Rationale for Exclusion - Background Criterion Chromium (Hexavalent) N9/L NE Shallow 5.7 7 0.076 - 7.1 1.5 Transition Zone 3 6 0.01 - 3.3 0.03 - 12 6.0 Bedrock 3.9 8 0.012 - 11.8 2.4 0.2 0 - o 0 o N v 1 0 o N Variable o o o N No means exceed comparative criteria 0.9 0 - No means exceed comparative criteria 0.3 0 - No means exceed comparative criteria Shallow NE 5 0.19 - 5.6 7.1 1.4 3 AL -IS, CCR-9S, GWA-15S 3 0 0 Y Three locations with detection of lithium above background. Does not exhibit a discernible plume; however, other CCR-related constituents present above comparative criteria AB -ID, AL -ID, CCR-41), Lithium pg/L NE Transition Zone NE 10 2.5 - 10.9 2 - 95.39 61.7 6.2 6 CCR-5D, CCP--9DA, GWA- ID y 6 6 0 Y Conservative Exceedances depict a plume -like distribution likely attributed to the ash basin Bedrock NE 11 3.8 - 11 20.8 1.9 5 AB-1BR, AB-1BRL, AB- 1 BRILL, AL-SBR, MW-14BR 5 5 0 Y Three locations (one location with three intervals) with detection of lithium above background. Two locations depict a plume -like distribution attributed to the ash basin Shallow 0.5 1 0.084 - 1.4 2.16 2.2 1 MW-8S 1 o o v Single location with detection of molybdenum above background. Does not exhibit a discernible plume; however, other CCR-related constituents resent above com arative criteria Single location with detection of molybdenum above background. Does not exhibit a discernible plume. Molybdenum pg/L NE Transition Zone 3.2 7 0.19 - 10.5 0.5 - 26 11.17 1.6 1 GWA-SD y 1 1 0 N Variable Concentrations are within range of Piedmont background datasets. Groundwater flow direction derived from water elevations collected over 30 monitoring events and velocity vectors derived from groundwater flow and transport modeling simultations indicate this location is beyond the downgradient flow path from the source area. Bedrock 3 4 0.13 - 6.2 1.1 0.3 0 - o o o v No means exceed comparative criteria AB -IS, AL -IS, CCR-3S, Shallow 303 303 9 - 223 2,350 7.8 10 GWA-10S, GWA-11S, GWA 15S, MW-7S, MW-8S, MW- 10 7 1 Y Exceedances depict a plume -like distribution likely attributed to the ash basin 9S MW-14S Transition Zone 665 665 81.4 - 732 5,537 8.3 11 GWA-10, GWA-10D, GWA- 11 11 2 Y Exceedances depict a plume -like distribution likely attributed to the ash basin Strontium pg/L NE 27 - 2,272 y Nan -Conservative AB-1BR, AB-1BRL, AB - Bedrock 253 253 140 - 407 3,230 12.8 7 SBRLL, AL-SBR, GWA- 7 6 1 Y Exceedances depict a plume -like distribution likely attributed to the ash basin 11 BR, MW-8BR, MW-14BR Notes: 0 - Reference Criterion 0- Evidence warrants COI Inclusion for corrective action �- Evidence does not warrant COI Inclusion for corrective action r - Constituent list reflects the COls Identified in the 2018 CSA Update report (SynTema, January 2018), In addition to CCR Rule Appendix IV constituents with statistically significant Increases above the groundwater protection standards, and constituents requested for Inclusion by NCDEQ. '- Background values include groundwater data collected September 2015 through October 2017. '- Updated background values include groundwater data collected February 2010 through December 2018. ° - Exceeds— ratio = calculated COI can concentration divided by criterion concentration. Assignment of conservative, non -conservative, or variable behavior Is based on geochemical modeling results. ° - The following wells were used to calculate mean concentrations for ash pore water: AS-3S, AS-45/SL, AS-5S, AB-65, AS-7S, AB-85, AS-10S/SL, AB-12S/SL, AS-13S, A15-145, AB-15S/SL, AS-17S, AS-18S, A15-20S, AS-21S, AL-3S - The following wells were used to calculate mean concentrations near or beyond compliance boundary: AB-IS/D/BR/BRL/BRLL, AB-2S/D, AL-1S/D/BR, CCR-3S/D, CCR-4S/D, CCR-SS/D, CCR-9S/DA, GWA-IS/D/BR, GWA-7S/D, GWA-IOS/D, GWA-IIS/D/BR, GWA-I55/D, MW-65/D, MW-75/D, MW-8S/D, MW-9S/D, MW-30S/D, MW-14S/D/BR > - greater than < - less than COI - constituent of Interest CSA - Comprehensive Site Assessment IMAC - Interim maximum allowable concentration MCL - maximum contaminant level pg/L - micrograms per liter mg/L - milligrams per liter pCi/L - picocuries per liter NA - Not Applicable NE - Not Established y - yes N - No Prepared by: ECW Checked by: VJH Page 2 of 2 Wells Within the Waste Boundary Well ID Boron Lithium Total Dissolved Solids Shallow Flow Zone AB-09S S AB-11S I ND ND NT Deep Flow Zone AB-03D S S AB-04D S S S AB-05D ND S NT AB-08D ND S S AB-09D ND S S AB-10D 11111EL D AB-11D ND S S AB-12D D D D AB-21D ND S S Bedrock Flow Zone AB-05BR ND A13-09BR ND S S AB-10BR S D S AB-12BR ND S S TABLE 6-7 SUMMARY TREND ANALYSIS RESULTS FOR GROUNDWATER MONITORING WELLS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Wells Between Waste Boundary and Compliance Boundary Well ID Boron Lithium Total Dissolved Solids Shallow Flow Zone CCR-12S D S CCR-13S S NT CCR-14S NT D CCR-15S ND NT S CCR-16S ND NT S CCR-01S ND S S CCR-02S S S MW_01 D S OB-01 D Ash Landfill NE NE NE Deep Flow Zone CCR-12D ND D S CCR-13D D CCR-14D S D CCR-15D ND D S CCR-16D ND S S CCR-01D ND NT NT CCR-02D S S Wells Near or Beyond Compliance Boundary Well ID Boron Lithium Total Dissolved Solids Shallow Flow Zone AB-01 S 5 S AB-02S ND S AL-01S 5 S NT CCR-03S ND NT S CCR-04S S CCR-05S D CCR-09S D S D GWA-01S ND S GWA-07S ND S S GWA-10S S GWA-11S S S GWA-15S S S MW-06S D D D MW-07S NT D MW-08S S MW-09S ND NT MW-10S ND S ND MW-14S D S S Deep Flow Zone AB-01 D i S NT AB-02D S AL-01 D S S CCR-03D D S tND S CCR-04D NT S CCR-05D D S CCR-09DA S S GWA-01D ND NT GWA-07D ND D S GWA-10D ND S GWA-11D S Wells Near or Beyond Compliance Boundary Well ID Boron Lithium Total Dissolved Solids Deep Flow Zone GWA-15D S S MW-06DS MW-07DS MW-09DNT kND MW-10D S S MW-14D S D Bedrock Wells AB-01 BR AB-01BRL AB-01BRLL S S S S S AL-01 BR S GWA-01BR ND S GWA-11BR ND S S MW-08D D S MW-14BR S Mann -Kendall trend analysis and results prepared by: Arcadis U.S. Inc. Checked by: MRC Notes: 1. Summary of results and trends are presented for samples collected from 2011 - 2019. 2. Trend results are presented when at least four samples were available and frequency of detection was >50%. Statistically significant trends are reported at the 95% confidence level. 3. Variability Index (VI) is calculated as the (maximum - minimum) / median concentration and is calculated using detected concentrations only. Values less than 1 indicate low variability in the dataset. ND = Greater than 50 percent of constituent concentrations were non -detect D = Statistically significant, decreasing concentration trend = Stable. No significant trend and variability is low (VI < 1) = No significant trend and variability is high (VI > 1) = Statistically significant, increasing concentration trend. NE = Insufficient number of samples to evaluate trend (n < 4) Page 1 of 1 TABLE 6-8 SEEPS CORRECTIVE ACTION STRATEGY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Seep ID Regulatory General Location Approximate Average Anticipated Seep Corrective Action Strategy Program Present Flow (cfs) Duke Energy anticipates flow will remain. As of Just NE of active basin November 2019 Duke Energy is conducting additional S-01 SOC and flows to intake 0.02 evaluations of the S-1 and is prepared to manage canal corrective action for this location. Active remediation and source control are anticipated to reduce COI migration to the area. Flow could become negligible, however, Duke Energy is Just east of active prepared to manage corrective action for this location if S-02 SOC basin near shoreline of NDF the seep is not dispositioned through source control intake canal measures. Active remediation and source control are anticipated to reduce COI migration to the area. Flow could become negligible, however, Duke Energy is Just east of active prepared to manage corrective action for this location if S-04 SOC basin near shoreline of NDF the seep is not dispositioned through source control intake canal measures. Active remediation and source control are anticipated to reduce COI migration to the area. Notes: cfs- cubic feet per second COI - Constituent of Interest SOC - Special Order by Consent NDF - no discernable flow present Prepared by: BDW Checked by: WCG Page 1 of 1 TABLE 6-9 WATER SUPPLY WELL ANALYTICAL RESULTS SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total(VI) Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 to 1* 300 NE 50 NE 100 20 NE 250 0.2* Soo 5^ 0.3* Impacted by Coal Ash? Comments Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 26.6 3.0 7.2 1 253 18.4 0.1 216 5.7 16.0 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1220 11.4 330 3.7 8.0 1 313 22.1 0.2 195 6.43 25.8 Background Data Set Range (Bedrock Flow Zone)2 0.11 - 1.25 0.071 j - 2.3 23 - 857 0.01 j - 1.8 25.9 j - 49.1 j 0.054 j - 1.9 1.2 -4 0.012 j - 11.8 0.23 j - 31 0.026 j - 3.9 16 - 1530 3.8 - 11 2.8 j - 385 0.13 j - 6.2 0.33 j - 22.8 0.17 j - 2.3 140 - 407 0.42 j - 23.9 0.016 j - 0.069 j 42 240 4.6E-05 j - 1.5E-04 j 0.099 j -26.6 Sample ID Sample Collection Date Analytical Results MR1 03/03/2015 0.29 j <1 13 <1 <500 0.84 j 7.2 <10 <10 <1 28 j NA 0.68 j 0.11 j <2 <1 28 11 <1 58 NA <5 N All COIs are below comparative criteria MR10 04/30/2015 <0.5 <0.5 38.8 <0.2 <5 <0.08 2.4 0.43 0.99 <0.5 260 NA 1.7 <0.5 <0.5 <0.5 59 <2 <0.1 65 NA 1.5 N All COIs are below comparative criteria MR-1000 10/12/2016 <0.5 0.17 36 <0.1 <25 0.54 2.2 0.7 1.4 <0.1 <50 NA 0.76 <0.5 1.6 <0.5 95.4 <2 NA 91 NA 1.9 N All COIs are below comparative criteria MR-1001 10/11/2016 <0.5 <0.1 47.7 <0.1 <25 <0.08 4.8 1.2 1.8 <0.1 <50 NA 1.3 <0.5 0.86 <0.5 140 <2 NA 67 NA 1.1 N All COIs are below comparative criteria MR-1002 09/23/2016 <0.5 <0.1 23.1 <0.1 <25 <0.08 1 6.2 7.2 <0.1 <50 NA 0.62 <0.5 <0.5 <0.5 68.5 <2 NA 66 NA 5 N All COIs are below comparative criteria MR-1003 10/18/2016 <0.5 0.23 34.3 0.12 <25 <0.08 7.6 2.4 2.6 <0.1 <50 NA 10.5 <0.5 0.59 <0.5 111 3.8 NA 81 NA 1 N All COIs are below comparative criteria MR-1004 09/23/2016 <0.5 <0.1 44.9 <0.1 <25 0.24 1.1 2 2.3 <0.1 <50 NA 1.1 <0.5 <0.5 <0.5 160 <2 NA 35 NA 3.7 N All COIs are below comparative criteria MR-1005 01/05/2017 <0.5 <0.1 45.2 <0.1 <25 <0.08 2.1 2.5 1.6 <0.1 <50 NA 0.85 <0.5 <0.5 <0.5 103 <2 NA 67 NA 4.4 N All COIs are below comparative criteria MR-1006 O1/05/2017 <0.5 <0.1 48.6 <0.1 <25 <0.08 3.8 0.77 1.1 <0.1 <50 NA 1.2 <0.5 1 <0.5 563 <2 NA 107 NA 2.3 N Located west and sidegradient of ash basin. Strontium exceedance possible from natural source. MR-1007 02/21/2017 <0.5 <0.1 412 0.2 <25 <0.08 6.4 1.1 1.5 0.34 <50 NA 6.2 <0.5 3.2 <0.5 156 <2 NA 115 NA 0.42 N All COIs are below comparative criteria MR-1008 02/21/2017 <0.5 <0.1 30.8 <0.1 <25 <0.08 1.4 1.7 2.2 <0.1 <50 NA 0.59 <0.5 <0.5 <0.5 98.9 <2 NA 55 NA 3.1 N All COIs are below comparative criteria MR-1009 02/21/2017 <0.5 <0.1 20.5 <0.1 <25 <0.08 2 0.63 0.93 <0.1 268 NA 3.6 <0.5 <0.5 <0.5 75.5 <2 NA 84 NA 3.4 N All COIs are below comparative criteria MR-1010 04/26/2017 <0.5 <0.1 30.1 <0.1 <25 <0.08 4 5.8 3.1 <0.1 <50 NA 0.91 <0.5 <0.5 <0.5 172 1.2 NA 91 NA 5.8 N All COIs are below comparative criteria MR11 04/30/2015 <0.5 <0.5 48.5 <0.2 <5 <0.08 1.3 0.52 0.87 <0.5 <50 NA 0.72 <0.5 <0.5 <0.5 78.2 2 <0.1 71 NA 1 N All COIs are below comparative criteria MR12 02/05/2015 <1 2.9 j 34 <2 <130 <0.1 2.3 <20 <25 <25 330 NA 0.088 j 1O j <5 99 <1 <0.5 93 B NA 12 j N All COIs are below comparative criteria MR13 03/03/2015 <3 <10 11.4 <1 <100 <1 1.9 <20 <10 <5 <50 NA <10 <10 <10 <10 106 <10 <1 56 NA 1.97 All COIs are below comparative criteria MR13 07/31/2015 <0.5 <0.5 32.1 <0.2 <5 <0.08 1.1 0.18 0.56 <0.5 <50 NA 0.79 4.7 <0.5 <0.5 353 8.4 <0.1 85 NA 2.8 N Located west and sidegradient of ash basin. Molybdenum and Strontium exceedances Possible from natural source. MR14 02/05/2015 <1 <1 49 <0.4 <25 <0.1 2.3 <20 <5 <5 210 NA <5 <10 <5 <1 77 <1 <0.5 67 NA <5 MR14 O5/22/2015 <0.5 <0.5 49.5 <0.2 <5 <0.08 2.3 0.65 0.82 <0.5 <50 NA 1.5 <0.5 <0.5 <0.5 85.3 <2 <0.1 38 NA 1.1 N All COIs are below comparative criteria MR16 02/18/2015 <0.5 <2 86.8 <0.5 <50 <0.15 7 <5 <2 <1 969 NA 131 <2 <0.5 <2 103 16 <0.5 125 NA 0.36 MR16 O8/13/2015 <0.5 <0.5 86.5 <0.2 <5 <0.08 1 10.2 <0.03 <0.5 <0.5 718 NA 112 <0.5 <0.5 <0.5 101 18.7 <0.1 140 NA <1 N All COIs are below comparative criteria MR17 02/05/2015 <1 <1 12 <0.4 <25 <0.1 1.4 <20 <5 <5 240 NA <5 <10 <5 <1 160 <1 <0.5 45 NA <5 MR17 O5/20/2015 <0.5 <0.5 10.6 <0.2 <5 <0.08 1.3 0.25 <0.5 <0.5 <50 NA <0.5 <0.5 <0.5 <0.5 189 <2 <0.1 46 D6 NA 2.6 N All COIs are below comparative criteria MR18 02/05/2015 <5 <5 <25 <2 <130 <0.5 3.3 <20 <25 <25 500 NA <25 <50 <25 <5 240 1.6 <2.5 88 NA <25 MR18 O5/20/2015 <0.5 <0.5 17 <0.2 <5 <0.08 3.5 0.037 <0.5 <0.5 <50 NA 2 <0.5 <0.5 <0.5 201 2.8 <0.1 82 NA 1.8 N All COIs are below comparative criteria MR2 Office 03/03/2015 <1 <1 31 <1 <500 <1 1.2 <10 4.5 <1 82 NA <5 <2 <2 <1 100 <1 <1 68 NA 5.5 All COIs are below comparative criteria MR2 Office O8/03/2015 <0.5 <0.5 90.2 <0.2 <5 0.086 1.1 <0.03 <0.5 <0.5 109 NA 17.2 2.1 3.2 <0.5 378 3.4 <0.1 92 NA 2.8 N Located south and sidegradient of ash basin. Outside half -mile radius from basin. Strontium exceedance possible from natural source. MR2 Plant 03/03/2015 <1 <1 130 <1 <500 <1 <1 <30 2.1 <1 3,700 NA 50 <2 <2 <1 4 <1 130 NA <5 N Located south and sidegradient of ash basin. Outside half -mile radius from basin. Iron exceedance possible from natural source. MR20 02/05/2015 <1 <5 14 <2 <130 <0.1 3.3 <20 <25 <25 NA <25 <10 <25 <5 170 1.3 <0.5 100 NA <25 MR20 07/31/2015 <0.5 <0.5 14 <0.2 <5 <0.08 3.1 0.43 0.96 <0.5 <50 NA <0.5 2.2 <0.5 <0.5 132 2.2 <0.1 107 NA 2.8 N All COIs are below comparative criteria MR21 02/05/2015 <1 <5 82 <2 <130 <0.5 4 <20 <25 <25 190 NA 34 <50 <25 <5 <50 <1 <0.5 49 NA <25 All COIs are below comparative criteria MR21 O5/21/2015 <0.5 <0.5 74.6 <0.2 <5 <0.08 4.1 0.15 <0.5 0.75 <50 NA 17.9 <0.5 0.66 <0.5 9.7 <2 <0.1 26 NA <1 N All COIs are below comparative criteria MR22 04/30/2015 <0.5 <0.5 79.3 <0.2 <5 <0.08 2.3 0.56 0.91 <0.5 <50 NA 3.8 <0.5 0.55 <0.5 34.1 <2 <0.1 55 NA <1 N All COIs are below comparative criteria MR23 02/12/2015 <1 <5 110 <1 <100 <0.1 <5 <10 1 <1 <50 NA <5 <5 <5 <5 270 <1 <0.1 <25 NA 3 MR23 O8/13/2015 <0.5 <0.5 121 <0.2 <5 <0.08 27.6 1.1 1.5 <0.5 <50 NA 1.2 <0.5 <0.5 <0.5 278 2.7 <0.1 194 NA 2.6 N All COIs are below comparative criteria MR23 (State Well) 02/12/2015 <10 <2 130 <5 <50 <0.5 25 <50 <10 <50 <50 NA <10 <10 <2 <5 280 <2 <2 155 NA <25 N All COIs are below comparative criteria MR25 03/03/2015 <1 <1 47 <1 <500 <1 7.8 <10 <1 <1 <50 NA <5 <2 <2 <1 110 1 <1 <1 150 NA <5 MR25 08/13/2015 <0.5 <0.5 53.8 <0.2 <5 <0.08 6.5 0.96 1.1 <0.5 <50 NA 1.2 <0.5 <0.5 <0.5 110 3.1 <0.1 108 NA 2 N All COIs are below comparative criteria MR26 02/12/2015 <1 <5 56 <1 <100 <0.1 2.68 <10 1 <1 <50 NA I <5 <5 <5 <5 170 1.12 <0.1 80 NA 3 MR26 08/14/2015 <0.5 <0.5 52 <0.2 <5 <0.08 3 1.2 Al 1.4 <0.5 <50 NA <0.5 <0.5 <0.5 <0.5 149 2 <0.1 66 NA 2.9 N All COIs are below comparative criteria MR26 (State Well) 02/12/2015 <10 <2 57 <5 <50 <0.5 3.4 50 <10 <50 <50 NA <10 <10 <2 <5 160 <2 <2 76 NA <25 N All COIs are below comparative criteria MR28 04/30/2015 <0.5 <0.5 44.5 <0.2 <5 <0.08 14 MI064 1 <0.5 114 NA 4.4 <0.5 1.1 <0.5 162 2.4 <0.1 105 NA 1.9 N All COIs are below comparative criteria MR29 04/30/2015 <0.5 <0.5 37 <0.2 <5 <0.08 1.51.5 2.9 <0.5 <50 NA 3.2 <0.5 0.69 <0.5 106 <2 <0.1 59 NA 2.9 N All COIs are below comparative criteria MR30 02/18/2015 <0.4 0.39 j 30.5 <0.11 <20 <0.06 1.74 00.41 3.22 <0.03 27 NA <2 0.67 j 0.61 0.43 j 163 5 <0.06 68 NA 2.24 N All COIs are below comparative criteria MR31 07/31/2015 <0.5 <0.5 23.3 <0.2 <5 <0.08 1 61.4 1.5 <0.5 <50 NA 0.81 <0.5 <0.5 <0.5 46 <2 <0.1 68 NA 4.7 N All COIs are below comparative criteria MR32 02/23/2015 <0.1 5.12 0.1 106 NA NA Invalid dataset; turbidity greater than 10 NTUs MR32 08/03/2015 <0.5 <0.5 107 <0.2 <5 <0.08 5.7 0.88 <0.5 428 NA 26.9 <0.5 <0.5 <0.5 99.6 <2 <0.1 74 NA 2.2 N All COIs are below comparative criteria MR33 05/21/2015 <0.5 <0.5 26.7 <0.2 <5 <0.08 2.9 0.9 1 <0.5 <50 NA <0.5 <0.5 <0.5 <0.5 46.7 <2 <0.1 57 D6 NA 1.7 N All COIs are below comparative criteria MR35 05/21/2015 <0.5 <0.5 18 <0.2 <5 <0.08 1.4 <0.03 <0.5 <0.5 65.4 NA 23.5 1.3 <0.5 <0.5 95 5 <0.1 96 NA 2 N All COIs are below comparative criteria MR36 05/22/2015 <0.5 <0.5 <0.3 <0.2 <5 <0.08 2.7 <0.03 <0.5 <0.5 105 NA 0.54 <0.5 <0.5 <0.5 <0.5 11.7 <0.1 75 NA <1 N All COIs are below comparative criteria MR37 05/21/2015 <0.5 <0.5 32.3 <0.2 <5 <0.08 5.3 2.7 2.8 <0.5 <50 NA 1 4.1 <0.5 <0.5 <0.5 21.9 <2 <0.1 2,040 NA <1 N Located northwest and upgradient of ash basin. Total dissolved solution exceedance Q0al fr m n r lsource, MR38 05/22/2015 <0.5 <0.5 91.7 0.21 <5 <0.08 1.5 1.3 1.7 <0.5 <50 NA 5.3 <0.5 0.51 <0.5 36 <2 <0.1 224 NA <1 N All COIs are below comparative criteria MR4 02/05/2015 <1 0.66 j 370 0.19 j <25 0.12 B 55 <20 <5 0.36 j 1,200 NA 30 B <10 3.5 j 0.3 j 580 <1 <0.5 200 B NA <5 N Located north and upgradient of ash basin. Strontium exceedance i fr mn rl r . MR40 07/31/2015 <0.5 <0.5 17.4 <0.2 <5 0.09 2.8 0.5 0.56 <0.5 <50 NA 5.1 <0.5 <0.5 <0.5 100 <2 <0.1 97 NA 1.5 N All COIs are below comparative criteria MR42 07/31/2015 <0.5 <0.5 35 <0.2 <5 <0.08 4.1 0.63 0.96 <0.5 <50 NA <0.5 <0.5 <0.5 <0.5 60.3 <2 <0.1 47 NA <1 N All COIs are below comparative criteria MR43 05/28/2015 <0.5 <0.5 43 <0.2 <5 <0.08 1.6 2.4 4.8 <0.5 190 NA 1.9 <0.5 1.2 <0.5 76.3 <2 <0.1 90 NA 3.9 N All COIs are below comparative criteria MR44 04/30/2015 <O.5 <0.5 33 <0.2 5.1 <0.08 1.6 0.54 1.2 <0.5 327 NA 0.96 <0.5 <0.5 <0.5 196 <2 <0.1 93 NA 5.1 1 N JAII COIs are below comparative criteria Page 1 of 2 TABLE 6-9 WATER SUPPLY WELL ANALYTICAL RESULTS SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Analytical Parameter Antimony Arsenic Barium Beryllium Boron Cadmium Chloride Chromium Chromium Cobalt Iron Lithium Manganese Molybdenum Nickel Selenium Strontium Sulfate Thallium Total Dissolved Solids Total(VI) Radium Vanadium Reporting Units pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L 15A NCAC 02L Standard 1* 10 700 4* 700 2 250 10 to 1* 300 NE 50 NE 100 20 NE 250 0.2* Soo 5^ 0.3* Impacted by Coal Ash? Comments Background Threshold Values (Bedrock Flow Zone)' 0.5 0.6 435 0.2 50 0.08 4.5 3.9 8.3 2.8 792 --- 26.6 3.0 7.2 1 253 18.4 0.1 216 5.7 16.0 Background Threshold Values (Bedrock Flow Zone) 1.0 1.1 840 1.0 50 1.0 3.6 8.1 11.2 2.6 1220 11.4 330 3.7 8.0 1 313 22.1 0.2 195 6.43 25.8 Background Data Set Range (Bedrock Flow Zone)2 0.11 - 1.25 0.071 j - 2.3 23 - 857 0.01 j - 1.8 25.9 j - 49.1 j 0.054 j - 1.9 1.2 - 4 0.012 j - 11.8 0.23 j - 31 0.026 j - 3.9 16 - 1530 3.8 - 11 2.8 j - 385 0.13 j - 6.2 0.33 j - 22.8 0.17 j - 2.3 140 - 407 0.42 j - 23.9 0.016 j - 0.069 j 42 240 4.6E-05 j - 1.5E-04 j 0.099 j -26.6 Sample ID Sample Collection Date Analytical Results MR45 05/28/2015 <0.5 <0.5 127 <0.2 <5 <0.08 6.2 0.73 1 <0.5 <50 NA 12 <0.5 0.97 <0.5 37.4 <2 <0.1 65 NA <1 N All COIs are below comparative criteria MR46 07/31/2015 <0.5 <0.5 38.7 <0.2 <5 <0.08 1.6 0.6 0.97 <0.5 <50 NA 10.2 <0.5 <0.5 <0.5 45.7 2.3 <0.1 55 NA 1.2 N All COIs are below comparative criteria MR47 08/04/2015 <0.5 <0.5 83.5 <0.2 <5 <0.08 1.1 1.3 1.6 <0.5 <50 NA 0.86 <0.5 0.72 <0.5 129 <2 <0.1 50 D6 NA 1.7 N All COIs are below comparative criteria MR48 10/23/2015 <0.5 <0.5 58.4 <0.2 <5 <0.08 2.5 0.98 H3 1.4 <0.5 <50 NA 5.4 <0.5 0.52 <0.5 55.8 <2 <0.1 49 NA 1.1 N All COIs are below comparative criteria MR6 02/18/2015 <0.5 <2 52.9 <0.5 <50 <0.15 4 <5 <2 <1 <25 NA <2 <2 <0.5 <2 309 T <5 <0.5 119 NA 1.29 MR6 08/07/2015 <0.5 <0.5 50.5 <0.2 <5 <0.08 4.7 0.83 1 <0.5 <50 NA 0.92 <0.5 <0.5 <0.5 291 <2 <0.1 103 NA 1.5 N All COIs are below comparative criteria MR8 02/18/2015 <0.5 <2 12.7 <0.5 <50 <0.15 2 <5 <2 <1 <25 NA <2 2.8 <0.5 <2 50 <5 <0.5 95 NA 2.65 MR8 08/05/2015 10.5 <0.5 14 <0.2 <5 <0.08 2.2 0.56 0.81 <0.5 <50 NA 1.8 1.9 <0.5 <0.5 44.1 2.6 <0.1 98 NA 2.4 N All COIs are below comparative criteria MR9 02/05/2015 <1 <1 18 <0.4 <25 <0.1 1.3 <20 <5 <5 180 NA <5 <10 <5 <1 81 <1 <0.5 88 NA 5.8 MR9 05/20/2015 <0.5 <0.5 17.6 <0.2 <5 <0.08 1 0.68 0.92 <0.5 <50 NA <0.5 <0.5 <0.5 <0.5 83.5 <2 <0.1 83 NA 6.4 N All COIs are below comparative criteria Prepared By: ECW Checked By: CMH Notes: - Background threshold values were calculated using data from background groundwater samples collected June 2015 to September 2017. - Background threshold values were calculated using data from background groundwater samples collected March 2011 to December 2018. Bold text - greatest comparative value O - bold highlighted concentration indicates value is greater than the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202 Standard and IMAC is April 1, 2013) - bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard O - highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard - highlighted concentration indicates turbidity value is out of range [>10 Nephelometric Turbidity Units (NTUs)] or pH value was not measured. Results are deemed invalid. * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. < - concentration not detected at or above the adjusted reporting limit. NE - not established NA - not available mg/L - milligrams per liter pg/L - micrograms per liter pCi/L - picocuries per liter j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. H3 - Sample was received or analysis requested beyond the recognized method holding time. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 10X the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. D6 - The precision between the sample and sample duplicate exceeded laboratory control limits. MI - Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable. Page 2 of 2 TABLE 6-10 NPDES PERMITS LIMITS AND ANTICIPATED GROUNDWATER REMEDIATION PARAMETER LEVELS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC NPDES Permit Parameter Outfall 00210 Outfall 005 Geomean Concentration of Anticipated Groundwater Discharge 9 Monthly Average Daily Maximum Monthly Average Daily Maximum Flow (million gallons/day) Not specified 1 Monitor and Report Not applicable Oil & Grease 9.0 mg/L 12.0 mg/L 15.0 mg/L 20.0 mg/L Not applicable Total Suspended Solids (TSS)' 20.0 mg/L 50.0 mg/L 30.0 mg/L 50.0 mg/L 3.7 mg/L Total Arsenic 397.1 pg/L 1 11,121 pg/L Monitor and Report 0.3 pg/L Total Cadmium, pg/L Not applicable Monitor and Report Not applicable Total Copper 3 1.0 mg/L 1.0 mg/L 68.8 µg/L 1 76.8 µg/L 0.9 mg/L Total Chromium, pg/L Monitor and Report Not applicable Total Iron 3 1.0 mg/L 1.0 mg/L 1.0 mg/L 1 1.0 mg/L 0.252 mg/L Total Lead, pg/L Monitor and Report Not applicable Total Mercury, ng/L Monitor and Report Monitor and Report Not applicable Total Nickel, pg/L Monitor and Report Not applicable Total Selenium, pg/L Monitor and Report Monitor and Report 1.0 pg/L Total Silver, pg/L Monitor and Report Not applicable Total Zinc, pg/L Monitor and Report Not applicable BOD, 5-day, 20°C Z 30.0 mg/L 45.0 mg/L Not applicable Nitrate/nitrite as N, mg/L Monitor and Report Not applicable Sulfate, mg/L Monitor and Report 32.2 pg/L Chloride, mg/L Monitor and Report 41.4 mg/L Bromide, mg/L Monitor and Report Monitor and Report Not applicable Fluoride, mg/L Not applicable TDS, mg/L Monitor and Report 322 mg/L Hardness, mg/L Monitor and Report Monitor and Report Not applicable Total Nitrogen (NO2+NO3+TKN), mg/L Monitor and Report Monitor and Report Not applicable Total Phosphorus, mg/L Monitor and Report Monitor and Report Not applicable Chronic Toxicity See Part I, Section A. (17.) See Part I, Section A. (17.) Not applicable pH 7 Between 6.0 and 9.0 S.U. Between 6.0 and 9.0 S.U. 5.8 S.U. Other COIs Not Specified in the NPDES Permit Barium Not applicable Not applicable Not applicable Not applicable 107.2 pg/L Beryllium Not applicable Not applicable Not applicable Not applicable 0.18 pg/L Boron Not applicable Not applicable Not applicable Not applicable 533 pg/L Cobalt Not applicable Not applicable Not applicable Not applicable 0.75 pg/L Hexavalent Chromium Not applicable Not applicable Not applicable Not applicable 0.09 pg/L Lithium Not applicable Not applicable Not applicable Not applicable 5.1 pg/L Manganese Not applicable Not applicable Not applicable Not applicable 96.0 pg/L Molybdenum Not applicable Not applicable Not applicable Not applicable 0.57 pg/L Radium total 8 Not applicable Not applicable Not applicable Not applicable 4.13 pCi/L Strontium Not applicable Not applicable Not applicable Not applicable 945 pg/L Thallium Not applicable Not applicable Not applicable Not applicable 0.13 pg/L Prepared by: WCG Checked by: BDW Notes: Constituents indicated as "not applicable" are not constituents of interest associated with the source area pg/L - Micrograms per liter mg/L - Milligrams per S.U. - Standard Unit 1 - Effluent sampling shall be conducted at the discharge from the ash settling basin prior to mixing with any other waste stream(s). 2 - The facility shall continuously monitor TSS concentrations when the dewatering process commences and the dewatering pump shall be shut off automatically when one half of the Daily Maximum limit (15 minutes average) is exceeded. Pumping will be allowed to continue if interruption might result in a dam failure or damage. The continuous TSS monitoring only required when the pumps are employed for dewatering. 3 - The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being discharged. - The facility shall continuously monitor pH when the dewatering process commences and the dewatering pump shall be shut off automatically when 15 minutes running average pH falls below 6.1 S.U., or rises above 8.9 S.U. Pumping will be allowed to continue if interruption might result in a dam failure or damage. Continuous pH monitoring is only required when the pumps are employed for dewatering. 9 - Arithmetic average, the geomean is not applicable for data sets containing non -positive numbers. 9 - Groundwater quality data from 2018 and 2019 quarterly sampling events from the following wells completed in the shallow, deep, and bedrock flow zones. The monitoring wells are located near proposed extraction wells in the ash basin vicinity and north of the ash basin dam: • AB-01BR,-01BRL,-016RLL; • CCR-14D, -14S; MW-02; • AB-01D,-01S; CCR-15D,-15S; • MW-06D,-06S; • AL-016R,-01BRL,-01D,-01S; • CCR-16D,-16S; MW-07D,-07S; • CCR-09DA, -09S; • GWA-1I13R, -11D, -11S; • MW-08D, -08S; • CCR-11D,-11S; GWA-15D,-15S; . MW-10D,-10S; and • CCR-13D,-13S; • MW-01; MW-14BR, -14BRL, -14D, -14S. 10 - Outfall 002 effluent limitations during dewatering phase Page 1 of 1 TABLE 6-11 FEATURE IRRIGATION SYSTEM SETBACK CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Feature Irrigation System Setback (feet) Spray Drip Private residence 400 100 Place of assembly owned by permittee 200 15 Surface waters 100 100 Property line 150 50 Notes: Reference: 15A NCAC 02T .056 Prepared by: WCG Checked by: ECW Page 1 of 1 TABLE 6-12 REMEDIAL TECHNOLOGY SCREENING SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Summary of Remedial Technology Retain Technology for Further Consideration Screening Yes/No Rationale Technology COIs pose no unacceptable risk to human health or the Monitored Natural Attenuation (MNA) Yes environment under conservative exposure scenarios. MNA could be implemented in conjunction with source control measures. In -Situ Technologies Technically challenging and costly. The saprolite and Low Permeability Barriers (LPB) No transition zone is too thick and bedrock is too deep to be feasible. Implementation could cause groundwater mounding and alternate flow paths. Groundwater Infiltration and Flushing Yes Possible application to enhance capture of mobile COIs (e.g., boron). Volume of CCR waste in the ash basin is too great to Encapsulation No implement as a groundwater corrective measure. Varied site conditions may make uniform application difficult. The saprolite and transition zone is too thick and bedrock is too deep to be feasible for implementation Permeable Reactive Barrier (PRB) Yes by open trenching. Injection of chemical amendments through a line of offset boreholes is technically feasible. Groundwater Extraction Vertical Extraction Wells Yes Would have potential application for alternatives involving groundwater extraction. Vertical extraction wells are deemed more cost Horizontal/Angular Extraction Wells No effective. Might have potential application for alternatives involving groundwater extraction where vertical wells are not feasible. Extraction Trenches No The saprolite and transition zone is too thick and bedrock is too deep to be effective. Hydraulic Fracturing No COI occurrence be bedrock is limited. Contingent option based on observed yield of extraction wells. Effectiveness is variable with the growing season. Flow Phytoremediation No and Transport modeling indicates that the flow rates needed to meet remedial objectives are too great to be achieved by phytoremediation. Groundwater Treatment Retained for remedial alternatives that include pH Adjustment Yes groundwater extraction, if needed to meet discharge requirements. Page 1 of 2 TABLE 6-12 REMEDIAL TECHNOLOGY SCREENING SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Summary of Remedial Technology Retain Technology for Further Consideration Screening Yes/No Rationale Technology Groundwater Treatment Technologies (Continued) Extracted groundwater is not expected to cause Precipitation No violations of the NPDES permit when discharged; therefore, precipitation technologies are not retained for further consideration. Requires a feasible and economical method to dispose Ion Exchange No of the regeneration effluent. Susceptible to geochemical interferences. Membrane Filtration No Pretreatment and a high volume of reject effluent that requires additional treatment prior to disposal. Groundwater Disposal Existing permitted discharges for wastewater are NPDES Permitted Discharge Yes already in place. Permit modification would be required for the discharge of treated groundwater. Acceptance of industrial waste water by the Sewer Publically Owned Treatment Works (POTW) No Authority is doubtful. Additional construction of sewer line along public ROW and monthly utility charges might be cost prohibitive. Non -Discharge Permit Soil type might be amenable to long term infiltration. Infiltration Gallery No Will help to mobilize residual COIs in the vadose zone, however, extracted groundwater would require treatment prior to infiltration to meet 02L standards. Land Application No Potential application to maintain vegetative cover following basin closure. Beneficial Reuse Fire Protection No Potential but limited application. Not feasible for long- term application. Non -Contact Cooling Water No Alkalinity and TDS may cause scaling problems for some applications. Dust Suppression and Truck Wash No Potential application, but not recommended at this time. Prepared by: WCG Checked by: BDW Page 2 of 2 TABLE 6-13 ALTERNATIVE 3 GROUNDWATER EXTRACTION AND CLEAN WATER INFILTRATION WELL SUMMARY CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Extraction Well System Number of Wells Flow Zone Total Depth (ft bgs) 42 transition zone / upper bedrock 125 - 165 24 upper bedrock 230 - 245 Total Extraction Well Count: 66 System Flow and operation assumptions: Average flow rate: 9.8 gpm per well. Total system extraction flow rate = 652 gpm. Extraction wells operate to maintain water level between 125 to 150 feet below ground surface. Average screen length: 100 feet Vertical Clean Water Infiltration Wells Number of Wells Flow Zone Total Depth (ft bgs) 24 saprolite zone 40 - 70 Total Infiltration Well Count: 24 System Flow and operation assumptions: Average infiltration rate: 11.5 gpm per well. Total system infiltration flow rate = 285 gpm. Infiltration wells operate to maintain water level at about 2 feet below ground surface. Average screen length: 15 feet Notes: ft bgs - feet below ground surface gpm - gallons per minute Prepared by: WCG Checked by: ECW Page 1of1 TABLE 6-14 ENVIRONMENTAL SUSTAINABILITY COMPARISONS FOR REMEDIATION ALTERNATIVES CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Remedial Alternative Remedial Alternative 1 — Groundwater Remediation by MNA Remedial Alternative 2 — Groundwater Remediation by Extraction, Clean Water Infiltration, and In -Situ Treatment Remedial Alternative 3 — Groundwater Remediation by Extraction and Clean Water Infiltration Emissions Units COz Emissions metric ton 9.66E+01 6.64E+04 1.17E+04 Onsite NO,, Emissions metric ton 1.46E-01 1.90E+00 4.73E+00 Onsite SOx Emissions metric ton 1.49E-02 1.37E-01 4.83E-01 Onsite PMjo Emissions metric ton 1.31 E-02 1.10E-01 4.26E-01 Total NO,, Emissions metric ton 2.00E-01 1.87E+02 3.91 E+01 Total SO,, Emissions metric ton 7.50E-02 1.79E+02 2.87E+01 Total PMjo Emissions metric ton 2.24E-02 3.43E+01 1.40E+01 Total Energy Used MMBTU 2.29E+04 3.87E+07 4.26E+06 Total Emissions metric ton 9.70E+01 6.68E+04 1.18E+04 Prepared by: GTC Checked by: CBC Notes: CO2 - Airborne emissions of carbon dioxide MMBTU - Million British Thermal Units MNA - Monitored Natural Attenuation NOx - Airborne emissions of nitrogen oxides (combination of nitrogen monoxide and nitrogen dioxide) SOx - Airborne emissions of sulfur oxides (combination of sulfur monoxide, sulfur dioxide, sulfur trioxide, and others) PM10 - Airborne emissions of particulate matter that is 10 micrometers or less in diameter Page 1 of 1 TABLE 6-15 MODELED CLEAN WATER INFILTRATION WELL DETAILS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Easting (ft NAD 83) Northing (ft NAD 83) Approximate Ground Surface Elevation (feet) Operational DTW Maintained In Well (ft BGS) Well Depth p (ft BGS) Targeted Flow Zone Total Simulated Flow (gpm) Vertical Clean Water Infiltration Wells IW-01 1,417,021.17 683,539.53 819 2 55 Saprolite 11.9 IW-02 1,417,053.64 683,477.46 809 2 48 Saprolite 11.9 IW-03 1,417,080.43 683,402.72 809 2 53 Saprolite 11.9 IW-04 1,417,095.94 683,322.35 811 2 54 Saprolite 11.9 IW-05 1,417,124.01 683,252.59 802 2 70 Saprolite 11.9 IW-06 1,417,140.93 683,193.37 807 2 53 Saprolite 11.9 IW-07 1,417,156.44 683,125.68 812 2 59 Saprolite 11.9 IW-08 1,417,174.78 683,058.00 813 2 62 Saprolite 11.9 IW-09 1,417,223.85 682,988.28 816 2 69 Saprolite 11.9 IW-10 1,417,277.55 682,929.54 814 2 72 Saprolite 11.9 IW-11 1,417,353.76 682,873.46 803 2 71 Saprolite 11.9 IW-12 1,417,411.94 682,767.47 807 2 73 Saprolite 11.9 IW-13 1,417,479.14 682,694.35 804 2 70 Saprolite 11.9 IW-14 1,417,565.41 682,638.94 803 2 70 Saprolite 11.9 IW-15 1,417,209.60 683,350.10 789 2 41 Saprolite 11.9 IW-16 1,417,238.10 683,238.30 788 2 39 Saprolite 11.9 IW-17 1,417,261.30 683,138.80 801 2 56 Saprolite 11.9 IW-18 1,417,327.70 683,047.60 799 2 59 Saprolite 11.9 IW-19 1,417,397.30 682,948.00 797 2 64 Saprolite 11.9 IW-20 1,417,455.70 682,871.00 796 2 64 Saprolite 11.9 IW-21 1,417,506.80 682,789.40 802 2 72 Saprolite 11.9 IW-22 1,417,557.30 682,745.60 793 1 2 1 63 1 Saprolite 11.9 IW-23 1,417,621.40 1 682,722.00 790 2 63 Saprolite 11.9 IW-24 1,417 687.20 682 686.60 773 2 50 Saprolite 11.9 rreNareu uy. i,necKeu uy. ru Notes: All depths are approximated and may change depending on site conditions. Flowrates are approximate and may change depending on site conditions. Screen bottom elevation assumes screen goes to top of competent bedrock and open bore below. 25 foot screen assumption for vertical infiltration wells DTW - depth to water ft - feet ft BGS - feet below ground surface gpm - gallons per minute NAD 83 - North American Datum 1983 Page 1of1 TABLE 6-16 MODELED GROUNDWATER EXTRACTION WELL DETAILS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Fasting (ft NAD 83) Northing (ft NAD 83) Approximate Ground Surface Elevation (feet) Operational DTW Maintained In Well (ft BGS) Well Depth (ft BGS) Targeted Flow Zones Total Simulated Flow m (gp ) Vertical Groundwater Extraction Wells EX-01 1,415,623.10 683,524.60 791 106 126 Saprolite/Transition Zone/Bedrock 8.5 EX-02 1,415,670.40 683,584.40 799 114 139 Saprolite/Transition Zone/Bedrock 8.5 EX-03 1,415,727.10 683,666.30 801 115 140 Saprolite/Transition Zone/Bedrock 8.5 EX-04 1,415,786.90 683,738.70 808 121 146 Saprolite/Transition Zone/Bedrock 8.5 EX-05 1,415,849.90 683,779.60 821 132 158 Saprolite/Transition Zone/Bedrock 8.5 EX-06 1,415,906.50 683,826.90 813 122 148 Saprolite/Transition Zone/Bedrock 8.5 EX-07 1,415,947.50 683,886.70 817 124 149 Saprolite/Transition Zone/Bedrock 8.5 EX-08 1,415,988.40 683,940.20 827 132 156 Saprolite/Transition Zone/Bedrock 8.5 EX-09 1,416,161.45 683,645.80 795 99 127 Saprolite/Transition Zone/Bedrock 10.1 EX-10 1,416,607.39 683,660.09 835 145 162 Saprolite/Transition Zone/Bedrock 10.1 EX-11 1,416,848.67 683,558.02 828 146 165 Saprolite/Transition Zone/Bedrock 10.1 EX-12 1,416,894.13 683,451.30 824 141 163 Saprolite/Transition Zone/Bedrock 10.1 EX-13 1,416,921.80 683,336.67 826 145 166 Saprolite/Transition Zone/Bedrock 10.1 EX-14 1,416,945.52 683,229.95 817 137 157 Saprolite/Transition Zone/Bedrock 10.1 EX-15 1,416,981.09 683,119.27 817 138 160 Saprolite/Transition Zone/Bedrock 10.1 EX-16 1,417,056.19 683,024.40 818 148 171 Saprolite/Transition Zone/Bedrock 10.1 EX-17 1,417,131.30 682,927.56 819 157 183 Saprolite/Transition Zone/Bedrock 10.1 EX-18 1,417,218.26 682,822.81 820 164 190 Saprolite/Transition Zone/Bedrock 10.1 EX-19 1,417,273.59 682,741.78 816 166 190 Saprolite/Transition Zone/Bedrock 10.1 EX-20 1,417,340.95 682,633.90 818 166 193 Saprolite/Transition Zone/Bedrock 10.1 EX-21 1,417,457.40 682,556.00 805 157 180 Saprolite/Transition Zone/Bedrock 10.1 EX-22 1,417,514.71 682,445.32 803 155 177 Saprolite/Transition Zone/Bedrock 10.1 EX-23 1,417,593.77 682,575.76 801 153 177 Saprolite/Transition Zone/Bedrock 10.1 EX-24 1,417,698.05 682,466.57 799 150 175 Saprolite/Transition Zone/Bedrock 10.1 EX-25 1,417,703.80 682,624.30 781 134 159 Saprolite/Transition Zone/Bedrock 10.1 EX-26 1,417,745.64 682,529.29 780 133 158 Saprolite/Transition Zone/Bedrock 10.1 EX-27 1,417,946.79 682,397.36 761 115 142 Saprolite/Transition Zone/Bedrock 10.1 EX-28 1,417,992.21 682,356.26 769 122 151 Saprolite/Transition Zone/Bedrock 10.1 EX-29 1,418,057.09 682,282.72 772 130 158 Saprolite/Transition Zone/Bedrock 10.1 EX-30 1,418,096.77 682,214.61 780 143 168 Saprolite/Transition Zone/Bedrock 10.1 EX-31 1,418,162.86 682,191.28 780 145 245 Bedrock 10.1 EX-32 1,418,180.10 682,109.50 785 149 250 Bedrock 10.4 EX-33 1,418,229.20 682,029.00 783 149 249 Bedrock 10.4 EX-34 1,418,233.11 681,907.25 781 149 249 Bedrock 10.4 EX-35 1,418,229.18 681,795.31 781 150 250 Bedrock 10.4 EX-36 1,418,187.94 681,673.55 784 153 253 Bedrock 10.4 EX-37 1,418,178.12 681,567.50 785 157 257 Bedrock 10.4 EX-38 1,418,123.13 681,404.50 777 152 252 Bedrock 10.4 EX-39 1,417,977.80 681,400.57 777 145 244 Bedrock 10.4 EX-40 1,417,889.43 681,481.09 780 140 240 Bedrock 10.4 EX-41 1,417,808.91 681,516.44 777 132 233 Bedrock 10.4 EX-42 1,417,667.70 681,436.50 771 119 218 Bedrock 10.4 EX-43 1,417,611.60 681,342.20 765 113 215 Bedrock 10.4 EX-44 1,417,552.90 681,227.40 764 126 224 Bedrock 10.4 EX-45 1,417,508.00 681,115.00 764 132 234 Bedrock 10.4 EX-46 1,417,444.00 681,029.00 760 132 236 Bedrock 10.4 EX-47 1,417,383.00 680,933.00 758 132 236 Bedrock 10.4 EX-48 1,417,343.30 680,813.20 743 118 222 Bedrock 10.2 EX-49 1,417,298.00 680,684.00 730 102 207 Bedrock 10.2 EX-50 1,417,261.01 680,586.11 719 92 196 Bedrock 10.2 EX-51 1,417,210.19 680,461.04 713 86 189 Bedrock 10.2 EX-52 1,417,144.50 680,351.60 715 87 189 Bedrock 10.2 EX-53 1,417,080.00 680,219.00 736 104 207 Bedrock 10.2 EX-54 1,417,019.63 680,140.34 753 121 222 Bedrock 10.2 EX-55 1,416,959.80 680 028.50 763 129 230 1 Bedrock I 10.2 Page 1 of 2 TABLE 6-16 MODELED GROUNDWATER EXTRACTION WELL DETAILS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Fasting (ft NAD 83) Northing (ft NAD 83) Approximate Ground Surface Elevation (feet) Operational DTW Maintained In Well (ft BGS) Well Depth (ft BGS) Targeted Flow Zones Total Simulated Flow (gpm) EX-56 1,417,165.00 683,479.00 794 113 138 Saprolite/Transition Zone/Bedrock 9.4 EX-57 1,417,197.00 683,387.00 789 111 135 Saprolite/Transition Zone/Bedrock 9.4 EX-58 1,417,217.00 683,291.00 791 115 141 1 Saprolite/Transition Zone/Bedrock 9.4 EX-59 1,417,249.00 683,183.00 795 127 152 Saprolite/Transition Zone/Bedrock 9.4 EX-60 1,417,277.00 683,087.00 806 144 169 Saprolite/Transition Zone/Bedrock 9.4 EX-61 1,417,365.00 682,991.00 793 134 166 Saprolite/Transition Zone/Bedrock 9.4 EX-62 1,417,429.00 682,903.00 796 145 169 Saprolite/Transition Zone/Bedrock 9.4 EX-63 1,417,492.60 682,823.40 800 152 176 Saprolite/Transition Zone/Bedrock 9.4 EX-64 1,417,529.00 682,759.00 793 144 170 1 Saprolite/Transition Zone/Bedrock 9.4 EX-65 1,417,653.00 682,723.00 773 125 151 Saprolite/Transition Zone/Bedrock 9.4 EX-66 1,417,587.60 682 732.70 782 1 135 161 Sa rolite/Transition Zone/Bedrock 9.4 Notes: All depths are approximated and may change depending on site conditions. Flowrates are approximate and may change depending on site conditions. Screen bottom elevation assumes screen goes to top of competent bedrock and open bore below. 15 ft screen assumption for vertical extraction wells DTW - depth to water ft - feet ft BGS - feet below ground surface gpm - gallons per minute NAD 83 - North American Datum 1983 Prepare y: GTC C ec e y: YG Page 2of2 TABLE 6-17 EFFECTIVENESS MONITORING PLAN ELEMENTS CORRECTIVE ACTION PLAN UPDATE MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Effectiveness Monitoring Plan (EMP) Implemented 30 days after CAP approval Remedial Action Groundwater Performance Monitoring Well Network AB-1BR CCR-14D° MW-6D PVSF-3S Upgradient/ Geochemical AB-1BRL CP-1S MW-7S' PVSF-3D Background Wells3 Transect Wells' AB-1BRLL CP-1D MW-7D' PVSF-3BR BG-1S AB-1S AB-1BRLLL CP-1BR' MW-8S PVSF-4S BG-ID AB -ID AB-2BR EMP-01BR2 MW-8D PVSF-4D BG-1BRA AB-2S AL-1S EMP-02BR2 MW-9S PVSF-4BR BG-2S AB-2D AL-1D EMP-03S2 MW-9D BG-2BR EMP-01S2 AL-1BR EMP-03D2 MW-12S BG-3S EMP-01D2 AL-1BRL EMP-03BR2 MW-12D BG-3D EMP-02S2 CCR-4S EMP-04S2 MW-14S BG-3BR EMP-02D2 CCR-4D EMP-04D2 MW-14D GWA-4S CCR-5S CCR-9S EMP-04BR2 MW-14BR GWA-4D CCR-5D CCR-9DA ILF-2S MW-14BRL GWA-SS GWA-15S CCR-11S4 ILF-2D PVSF-IS GWA-5D GWA-15D CCR-11D4 GWA-10S PVSF-ID GWA-6S MW_10S CCR-12S° GWA-10D PVSF-1BR GWA-6D MW-10D CCR-12134 GWA-11S PVSF-2S GWA-8S CCR-13S° GWA-11D PVSF-2D GWA-8D CCR-13134 GWA-11BR PVSF-2BR GWA-12S CCR-14S4 MW-6S PVSF-2BRL' GWA-12D Post -Closure Monitoring Plan (POMP) Implemented after completion of ash basin closure activities PCMP Groundwater Monitoring Well Network (background, downgradient of ash basin) A PCMP will be implemented at the Site in accordance with G.S. 130A-309.214(a)(4)k.2 after completion of ash basin closure activities. EMP Groundwater Quality''' PCMP Groundwater Quality (Semi -Annual Sampling Frequency) (Sampling frequency to be determined) Alkalinity Cobalt Selenium Aluminum Ferrous Iron Strontium Antimony Iron Sodium Barium Lithium' Sulfate Parameters and sampling frequency to be included Beryllium Magnesium Thallium in the PCMP in accordance with G.S. 130A- Bicarbonate Alkalinity Manganese Total Dissolved Solids (TDS)' 309.214(a)(4)k.2 when submitted. Boron Molybdenum Radium (total)' Calcium Nitrate + Nitrite Total Organic Carbon Chloride' Potassium Vanadium EMP and PCMP Groundwater Field Parameters Water Level Specific Conductivity Temperature pH Oxidation Reduction Potential Dissolved Oxygen EMP Duration PCMP Duration Annual Effectiveness Monitoring Evaluation and Reporting Annual Evaluation and Reporting 1) Summary of annual groundwater monitoring results 1) Summary of annual groundwater monitoring 2) Evaluate statistical concentration trends results 3) Comparison of observed concentrations to model predictions 2) Evaluate statistical concentration trends 4) Evaluation of compliance with applicable Standards 3) Comparison of observed concentrations to model 5) Evaluation of system performance and effectiveness predictions 6) Recommend plan adjustments, if applicable, to optimize the remedial action 4) Evaluation 02L compliance 5) Recommend plan adjustments, if applicable 5-Year Performance Review Reporting 1) Update background analysis At a frequency no greater than 5 years 2) Confirm Risk Assessment assumptions remain valid 1) Update background analysis 3) Re-evaluate effectiveness of technology 2) Confirm Risk Assessment assumptions remain 4) Verify modeling results, update model if needed valid 5) Modify corrective action approach, as needed, to achieve compliance goal established J 3) Verify model results, update if needed After ash basin closure and following ash basin closure certification, a PCMP will be implemented at the Site for a minimum of 30 years in accordance with G. S. 130A 30 days after CAP approval, the EMP will be implemented at the Site and will continue until there is a total of three 309.214(4)(k)(2). years of data confirming COIs are below applicable Standards at or beyond the compliance boundary, at which time Early termination: a request for completion of active remediation will be filed with NCDEQ. If groundwater monitoring results are below applicable Standards at the compliance boundary for If applicable standards are not met, the EMP will continue and transition to post -closure monitoring if necessary. three years, Duke Energy will request completion of corrective action in accordance with G.S. 130A- 309.214(a)(3)b. If groundwater monitoring results are above applicable Standards, the PCMP will continue. Prepared by: ECW Checked by: BDW Notes: 1) Select Flow path groundwater wells would have geochemical sondes installed for telemetry monitoring of the six groundwater field parameters. See Appendix O, Figure 2. 2) New EMP groundwater well proposed for performance monitoring. All other wells listed are existing groundwater monitoring wells. 3) Approved background groundwater monitoring location. 4) Groundwater monitoring well assumed to be abandoned from closure activities. Groundwater well location proposed to be replaced post -closure. 5) Proposed well to be installed in Quarter 4 - 2019. 6) Geochemically non -reactive constituents (i.e., conservative corrective action COIs) that best depict the areal extent of the plume; and monitor plume stability and physical attenuation either from active remedy or natural dilution/dispersion. 7) The number of monitoring wells and parameters may be adjusted based on additional data and the effects of corrective action. 8) Groundwater standards may be modified over time in accordance with 02L .0306(k). 9) Total radium to be monitored at select well locations, in general agreement with well currently monitored for radium under the Interim Monitoring Plan Italicized parameters - parameters for general water quality to evaluate monitoring data quality (electrochemical charge balance). Page 1 of 1