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HomeMy WebLinkAboutNC0003425_Roxboro Errata 5-5-20_20200505synTerra CORRECTIVE ACTION PLAN UPDATE REVISION 1: APRIL 23, 2020 Site Name and Location: Roxboro Steam Electric Plant 1700 Dunnaway Road Semora, NC 27343 Groundwater Incident No.: Not Assigned NPDES Permit No.: NC0003425 NCDEQ CCR Impoundment Ranking Low -Risk Date of Report: December 31, 2019 Permittee and Current Duke Energy Progress, LLC Property Owner: 410 South Wilmington Street Raleigh, NC 27601 (704) 355-7042 Consultant Information: SynTerra Corporation 148 River Street, Suite 220 Greenville, SC 29601 (864) 421-9999 Latitude and Longitude of Facility: N 36.484825 / W-79.072315 ���}Xtillll��1 ARO E N S 0. .i: 7 Cry ,wady,IF I16 r. UG N :CARQ[ kL TlenfrneA, NC PE 18675 Pfoject Engineer !1!1l555"F! TABLES TABLE 4-3 BACKGROUND VALUES FOR GROUNDWATER CORRECTIVE ACTION PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Constituent Reporting Unit 15A NCAC 02L Standard 2017 Background Threshold Values' 2019 Updated Background Threshold Values2 Piedmont Background Threshold Value Range Transition Flow Zone Bedrock Flow Zone Transition Flow Zone Bedrock Flow Zone pH S.U. 6.5 - 8.5 6.3 - 7.6 6.8 - 8.3 6.3 - 7.6 6.1 - 8.3 3.6 - 9 Alkalinity mg-CaCO3/L NE 273 317 283 379 19 - 379 Aluminum Ng/L NE 1237 378 734 183 100 - 1,238 Antimony Ng/L 1* 1 1 1 1 0.5 - 2.9 Arsenic Ng/L 10 1 1 1 6 0.2 - 6.35 Barium Ng/L 700 91 185 94 135 10.52 - 840 Beryllium Ng/L 1 4* 1 1 1 1 0.0625 - 1 Bicarbonate mg-CaCO3/L NE 273 317 284 388 19 - 388 Boron pg/L 700 50 50 50 50 50- 176.8 Cadmium Ng/L 2 1 1 1 1 0.08 - 1 Calcium mg/L NE 132 102 111 106 4- 111 Carbonate mg-CaCO3/L NE 5 5 5 5 5- 10 Chloride mg/L 250 150 120 180 130 3.34 - 250 Chromium Ng/L 1 10 25 4 22 4 1- 26 Chromium (VI) pg/L 10 17 0.2 12 1 0.03 - 12 Cobalt pg/L 1* 1 6 3 18 0.088 - 88.85 Copper Ng/L 1,000 10 1 10 2 0.5 - 17.15 Fluoride mg/L 2 --- --- 0.4 0.4 0.1 - 1.8 Iron Ng/L 300 1,210 4,227 1,293 5,130 56.3 - 37,500 Lead Ng/L 1 15 1 1 1 1 0- 2 Lithium Ng/L NE --- --- 26 27 2 - 95.39 Magnesium mg/L NE 42 32 45 39 1 - 45 Manganese Ng/L 50 405 1,198 260 1,773 7-9,170 Mercury Ng/L 1 0.1 0.05 0.05 0.05 0.05 -0.5 Methane Ng/L NE 10 367 10 1,120 1 - 2,505 Molybdenum Ng/L NE 4 35 8 22 0.5 - 26.2 Nickel Ng/L 100 19 2 17 3 0.87 - 48 Nitrate + Nitrit mg-N/L NE 3 0.3 4 0.4 0.02 - 6.3 Potassium mg/L NE 5 9 5 10 1.609 - 18.8 Selenium Ng/L 20 2 1 2 1 0.5 - 2.4 Sodium mg/L NE 36 38 36 57 6- 190 Strontium Ng/L NE 760 232 760 438 27 - 2,120 Sulfate mg/L 250 37 74 38 69 1.2 - 510 Sulfide mg/L NE 0.1 0.1 0.2 0.3 0.1 - 2 TDS mg/L 500 540 530 710 560 50- 1,200 Thallium Ng/L 0.2* 0.2 0.2 0.2 0.2 0.1 -0.2 TOC mg/L NE 3 4 2 11 1 - 12.3 Total Radium pCi/L 5^ 7 5 10 4 0.494 - 35 Total Uranium Ng/mL 1 0.03^ 0.005 0.003 0.004 0.006 0.0002 - 0.864 Vanadium Ng/L 0.3* 30 2 23 3 0.33 - 25.8 Zinc Ng/L 1,000 12 7 14 44 5- 140 Prepared by: HES Checked by: JHG Revised by: KTL Notes: 2017 background threshold values (BTVs) approved by North Carolina Department of Environmental Quality (NCDEQ) on September 1, 2017. Background threshold values have been rounded to similar levels of precision as 15A North Carolina Administrative Code (NCAC) 02L Standard or Interim Maximum Allowable Concentration (IMAC). ' - BTVs were calculated using data from background groundwater samples collected November 2010 to January 2017. - Updated BTVs were calculated using data from background groundwater samples collected November 2010 to November 2018. - Piedmont background threshold value ranges include the Duke Energy calculated 2017' and 20192 background threshold values from 10 Duke Energy facilities located in the Piedmont physiographic region (Allen Steam Station, Belews Creek Steam Station, Buck Steam Station', Cape Fear Steam Electric Plant', Cliff cle Steam Station, Dan River Steam Station', Marshall Steam Station, Mayo Steam Electric Plant, Riverbend Steam Station', and Roxboro Steam Electric Plant). --- - BTV was not calculated for constituent. * - IMAC of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. ^ - Federal Maximum Contaminant Level pg/L - micrograms per liter pg/mL - micrograms per milliliter mg/L - milligrams per liter mg-CaCO3/1- - 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 Rev. 1 23 April 2020 Page 1 of 1 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - EAST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. lag/L lag/L pg/L pg/L lag/L lag/L lag/L lag/L lag/L lag/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 - 7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)Z 6.3 - 7.61 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8-8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID Flow Zone Mean Result3 Background Locations BG-01 Transition 6.4 < 1 < 50 2.8 3.2 < 1 61.5 < 5 < 1 < 1 458 17.2 334 0.00055 18.3 BG-01BR Bedrock 6.9 < 1 < 50 0.1 1.2 < 1 53.3 224 2.3 < 1 177 17.6 310 0.00082 2.1 BG-02BR Bedrock 8.1 < 1 < 50 0.0 1.6 < 1 97.2 49.5 12.7 < 1 262 33.0 322 0.0031 0.35 CCR-112BR-BG Bedrock 6.4 < 1 < 50 - < 1 < 1 - - 7.3 < 1 - 19 193 - - MW-10BR Bedrock 6.9 < 1 < 50 0.2 < 1 14.6 11.5 187 11.0 < 1 173 39.6 330 0.0026 2.9 MW-14BR Bedrock 7.2 < 1 < 50 < 0.025 1.1 3.1 1530 360 2.7 < 1 181 12.8 362 0.00025 0.28 MW-15BR Bedrock 7.6 < 1 < 50 0.1 < 1 < 1 579 35.6 11.0 < 1 124 32.0 345 0.00067 0.27 MW-15D Transition 6.6 < 1 < 50 3.0 2.9 < 1 40.0 < 5 < 1 < 1 236 29.3 398 0.00066 10.0 MW-18BR Bedrock 7.9 < 1 < 50 < 0.025 < 1 1.3 1140 777 3.7 < 1 473 12.4 505 0.00048 < 0.3 MW-18D Transition 7.0 < 1 < 50 7.3 6.8 < 1 112 52.0 2.7 < 1 652 32.1 579 0.0031 1.3 MW-19BRL Bedrock 7.0 < 1 < 50 < 0.025 < 1 < 1 3928 1454 2.9 < 1 252 18.0 466 < 0.0002 0.35 MW-26BR Bedrock 7.2 < 1 < 50 < 0.025 < 1 < 1 1950 542 15.4 < 1 259 66.8 512 - 0.32 MW-29BR Bedrock 7.3 < 1 < 50 0.05 < 1 < 1 274 110 2.1 < 1 152 12.2 280 - 0.40 MW-30BR Bedrock 6.9 < 1 < 50 < 0.025 < 1 < 1 2174 1074 4.8 < 1 301 62.7 477 - 0.25 Near or Within the Waste Boundary Locations ABMW-044 Ash Pore Water 5.6 < 1 45000 < 0.025 < 1 6.41 71500 12300 774 < 1 9140 2200 3800 0.0241 1.63 ABMW-04BR4 Bedrock 6.2 < 1 < 50 < 0.025 0.711 j < 1 3710 1570 4.9 < 1 183 20 230 0.000117 j 0.635 ABMW-05 Ash Pore Water 7.4 < 1 25600 < 0.025 < 1 1.5 3728 1710 2828 < 1 4810 1300 2250 0.0062 0.59 ABMW-05D Transition 7.1 < 1 2870 < 0.025 < 1 < 1 32780 6308 14.3 < 1 498 13.1 252 < 0.0002 0.72 ABMW-06 Ash Pore Water 7.3 < 1 3014 0.030 < 1 < 1 1035 975 7.3 < 1 9924 169 738 - 1.4 ABMW-06BR Bedrock 6.7 < 1 < 50 0.028 < 1 < 1 74.8 720 2.1 < 1 208 61.4 332 - 0.39 ABMW-07BR Bedrock 6.9 < 1 1624 0.03 < 1 1.2 186 498 1.2 < 1 242 116 428 - 0.42 ABMW-07BRL Bedrock 7.6 < 1 168 0.027 < 1 < 1 224 63.6 5.5 < 1 796 244 532 - < 0.3 ABMW-07BRLL4 Bedrock 7.8 < 1 137 < 0.025 0.592 j < 1 460 64 2.52 < 1 634 90 400 0.00164 0.497 CCR-100BR Bedrock 7.1 < 1 < 50 - < 1 < 1 - - 6.1 < 1 - 27.8 440 - - CCR-100D Transition 7.0 < 1 < 50 - < 1 < 1 - - 1.9 < 1 - 22.5 423 - - CCR-101BR Bedrock 7.2 < 1 < 50 - < 1 < 1 - - 2.4 < 1 - 19 405 - - CCR-101D Transition 6.8 < 1 < 50 - < 1 31 - - 2.1 < 1 - 3.3 343 - - CCR-102BR Bedrock 6.5 < 1 < 50 - < 1 < 1 - - 2.5 < 1 - 370 813 - - CCR-103BR Bedrock 7.1 < 1 3883 - < 1 < 1 - - < 1 1.4 - 700 1275 - - CCR-104BR4 Bedrock 6.8 < 1 7700 - 0.572 j < 1 - - 5.43 15.8 - 1100 1900 - - CCR-105BR Bedrock 6.7 < 1 610 - < 1 < 1 - - 1.8 12.2 - 243 600 - - CCR-106BR Bedrock 6.7 < 1 1463 - < 1 < 1 - - 1.4 < 1 - 380 933 - - CCR-107BR Bedrock 6.2 < 1 3552 0.057 < 1 < 1 3.7 3.7 < 1 < 1 894 306 616 0.00012 12.5 CCR-108BR Bedrock 6.6 < 1 11360 0.086 < 1 < 1 < 10 74 224 23.9 1490 1044 2020 0.0055 6.3 CCR-109BR Bedrock 6.6 < 1 1305 - < 1 < 1 - - 2.9 < 1 - 513 1200 - - CCR-110BR Bedrock 6.2 < 1 17675 - < 1 7.1 - - 2082 47.7 - 1028 1713 - CCR-111BR Bedrock 6.6 < 1 4263 - 1.0 < 1 - - 1.7 171 - 650 1450 - - GMW-01A Transition 6.7 < 1 113 - < 1 2.0 - - < 1 4.9 - 69.5 373 - - GMW-02 Transition 6.7 < 1 5400 - < 1 < 1 - - < 1 3.4 - 865 1500 - - GMW-06 Transition 6.5 < 1 2525 0.77 1.0 < 1 37.0 1 12.6 < 1 58.1 1074 659 1250 0.0023 4.2 GMW-07 Bedrock 6.6 < 1 2800 0.25 1.2 < 1 61.1 < 5 1.6 13.0 835 346 1148 - 6.7 Rev. 1 23 April 2020 Page 1 of 3 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - EAST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. lag/L lag/L pg/L pg/L lag/L lag/L lag/L lag/L lag/L lag/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 - 7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)Z 6.3 - 7.61 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8-8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID I Flow Zone Mean Result3 Near or Within the Waste Boundary Locations (Continued) GMW-084 Bedrock 6.5 < 1 3910 0.036 3.2 < 1 42 52 3.3 < 1 909 480 1400 - 2 GMW-08R Bedrock 6.6 < 1 3444 0.099 < 1 0.705 26.9 213 13.0 < 1 911 420 1320 0.015 2.2 GMW-09 Bedrock 6.2 < 1 < 50 0.13 < 1 < 1 49.2 < 5 < 1 < 1 100 23.9 170 - 3.8 GMW-10 Bedrock 6.0 < 1 124 0.17 < 1 < 1 92.6 6.7 < 1 3.2 141 48.9 211 - 2.8 GMW-11 Bedrock 6.5 < 1 2958 0.28 < 1 < 1 64.7 < 5 0.85 106 503 454 932 - 6.5 MW-02BR4 Bedrock 6.2 < 1 < 50 < 0.025 < 1 3.7 20200 1450 1.96 < 1 599 47 520 - < 0.3 MW-03BR Bedrock 6.7 < 1 2744 0.027 < 1 1.3 186 48.4 < 1 2.5 1518 1360 2300 0.040 15.8 MW-11BR Bedrock 6.7 < 1 < 50 0.15 < 1 < 1 16.5 37.4 2.7 < 1 182 41.3 321 0.00067 5.0 MW-11D Transition 6.4 < 1 < 50 0.028 < 1 5.1 135 1228 1.4 < 1 329 37 300 0.00012 3.2 MW-20BRL Bedrock 7.4 < 1 < 50 0.026 < 1 < 1 78.6 412.4 1.1 < 1 200 12.5 257 - < 0.3 MW-21BRLR Bedrock 7.4 < 1 65.7 0.026 < 1 < 1 65.1 137 19.5 < 1 523 107 508 0.0058 1.1 MW-23BRR Bedrock 6.9 < 1 < 50 < 0.025 < 1 < 1 54.4 29 2.3 < 1 140 15.7 263 - 0.92 MW-24BR Bedrock 7.8 1.1 < 50 0.040 1.9 < 1 431 126 10.3 < 1 1682 64.4 290 - 0.32 MW-35BR4 Bedrock 7.3 < 1 937 0.064 0.339 j 0.528 j 222 102 5.15 0.51 j 347 220 570 0.0037 0.795 MW-35D4 Transition 6.4 < 1 8150 0.16 0.546 j 0.411 j 216 84 2.09 40.6 873 700 1410 0.00554 7.7 MW-35S4 Shallow 6.4 < 1 8270 0.17 0.607 j 0.774 j 127 97 0.968 j 37 1370 830 1320 0.00134 13.8 MW-37BR4 Bedrock 7.6 < 1 4200 0.38 0.775 j < 1 14 132 1.04 25.5 624 490 200 0.00239 2.18 MW-37D4 Transition 6.2 < 1 506 0.3 1.01 0.434 j 254 25 0.197 j 9.69 735 430 722 0.000638 5.44 MW-37S4 Shallow 6.1 < 1 416 0.061 M1 < 1 0.508 j 13 70 2.41 12.5 898 570 1070 0.00116 7.06 MW-108BRL4 Bedrock 6.8 < 1 22700 < 0.025 0.571 j 13.4 741 2530 1450 M4 < 1 2020 1900 3030 0.00345 1.33 MW-108BRLL4 Bedrock 7.8 0.517 j 4770 0.097 0.584 j < 1 188 225 261 < 1 414 400 927 0.00745 0.802 Near or Beyond the Compliance Boundary Locations CCR-113BR Bedrock 7.0 < 1 < 50 < 0.025 1.0 < 1 318 40.3 2.0 < 1 193 140 478 - 1.6 CCR-113D Transition 6.7 < 1 < 50 0.10 0.55 < 1 237 35.5 0.59 < 1 260 122 434 - 3.3 CW-01 Bedrock 6.1 < 1 < 50 0.032 < 1 < 1 96.8 66.4 < 1 < 1 458 101 436 0.00039 23.2 GPMW-01BR Bedrock 6.5 < 1 1554 < 0.025 < 1 < 1 817 137 3.5 < 1 1230 1120 1720 - 0.64 GPMW-01D Transition 6.5 < 1 1101 < 0.025 < 1 < 1 58.8 61 < 1 < 1 1476 1133 1733 - 4.0 GPMW-01S Shallow 6.2 < 1 1802 0.026 < 1 10.1 206 3232 < 1 < 1 2482 1186 1760 - 4.9 GPMW-02BR Bedrock 6.5 < 1 2492 < 0.025 < 1 < 1 232 1074 < 1 < 1 1290 1140 1980 - 1.5 GPMW-02D Transition 6.7 < 1 < 50 < 0.025 < 1 7.2 96840 9604 1.4 < 1 930 610 1100 - 0.69 GPMW-03BR Bedrock 7.4 < 1 227 < 0.025 < 1 < 1 215 43.4 3.5 < 1 861 486 750 - 0.39 GPMW-03D Transition 5.9 < 1 1345 0.046 < 1 4.0 284 602 < 1 57.8 1670 1220 1820 - 1.7 MW-01BR Bedrock 6.6 < 1 1952 0.071 2.6 1.5 409 547 < 1 9.1 530 138 664 - 16.4 MW-01BRL4 Bedrock 6.9 < 1 24.064 j < 0.025 0.436 j < 1 1420 1480 1.26 < 1 337 87 594 0.000654 0.367 MW-13BR Bedrock 6.2 < 1 < 50 0.072 < 1 2.0 117 141 1.6 < 1 424 33.8 386 0.00013 6.3 MW-16BR Bedrock 6.8 < 1 < 50 0.098 < 1 < 1 23.7 22.2 0.89 < 1 161 23.3 283 0.0011 3.0 MW-17BR Bedrock 7.2 < 1 < 50 0.047 < 1 < 1 593 252 2.7 < 1 887 36.9 371 0.00025 0.31 MW-22BR Bedrock 6.5 < 1 787 0.032 < 1 5.9 74.4 567 4.1 7.7 584 538 936 - 0.98 MW-22D Transition 6.1 < 1 487 < 0.025 < 1 5.3 12.2 1466 < 1 47.2 1361 960 1560 - 4.1 MW-25BR Bedrock 7.1 < 1 < 50 < 0.025 2.5 < 1 2225 583 4.6 < 1 1768 97.8 575 - 0.29 MW-27BR Bedrock 7.3 < 1 < 50 < 0.025 1.2 < 1 645 274 1.5 < 1 303 260 634 - < 0.3 MW-28BR Bedrock 7.5 < 1 50.4 0.029 1.6 < 1 621 219 6.6 < 1 326 69 408 - 0.98 Rev. 1 23 April 2020 Page 2 of 3 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - EAST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. lag/L lag/L pg/L pg/L lag/L lag/L lag/L pg/L lag/L lag/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 - 7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)2 6.3 - 7.61 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8 - 8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID I Flow Zone Mean Result3 Near or Beyond the Compliance Boundary Locations (Continued) MW-34BR4 Bedrock 7.1 < 1 1200 0.07 < 1 0.417 j 168 53 1.65 2 628 590 1140 0.0071 1.54 MW-34D4 Transition 6.7 < 1 537 0.42 0.654 j < 1 82 8 0.667 j 23.3 662 800 1240 0.0038 6.48 MW-36BR4 Bedrock 6.9 < 1 996 <0.025 0.357 j 0.483 j 136 34 2.12 2.22 855 950 1690 0.0105 0.946 MW-36D4 Transition 6.6 < 1 1220 0.041 < 1 0.378 j 26 180 2.4 27.2 786 1300 2000 0.00441 10.8 Notes: ' - Background threshold values were calculated using data from background groundwater samples collected November 2010 to January 2017. Z Background threshold values were calculated using data from background groundwater samples collected November 2010 to November 2018. 3 - Statistical mean calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. 4- Wells with datasets containing fewer than four valid results, the most recent valid sample data up to June 2019 was used. Mean values have been rounded to similar levels of precision as 15A North Carolina Administrative Code (NCAC) 02L Standard or Interim Maximum Allowable Concentration (IMAC). Background values have not been established for the shallow flow zone at this time, therefore, data sets are compared to transitional flow zone criteria for comparison purposes only. Mean or geomean results were used based on the central tendency of the data set. 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 0 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) 0 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 within range of background threshold values for constituents where there is no regulatory standard, or background threshold values are greater than 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 BTVs - Background Threshold Values COIs - Constituents of Interests NE - not established NTUs - Nephelometric Turbidity Units mg/L - milligrams per liter j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. M1 - Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable. M4 - The spike recovery value was unusable since the a-lyte concentration in the sample was disproportio-te to the spike level. pCi/L - picocuries per liter Ng/mL - micrograms per milliliter Ng/L - micrograms per liter RO - The data are unusable. The sample results are rejected due to serious deficiencies in meeting QC criteria. The analyte may or may not be present in the sample. S.U. standard unit Prepared by: KTL Checked by: TAW Rev. 1 23 April 2020 Page 3 of 3 TABLE 6-6 COI MANAGEMENT MATRIX - EAST ASH BASIN CORRECTIVE ACTION PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Constituent Standards and Values - 02L Criterion Lines of Evidence (LOE) - 02L Criterion Rationale - 02L Criterion Shallow NE NE NE 1,802 2.6 1 GPMW-1S NA 1 1 Y Multiple locations with means greater than 02L near or beyond the compliance boundary and which Boron 700 (pg/L) Transition Zone 50 50 <50 <50 50- 176.8 1,345 1.9 3 GPMW-ID, GPMW-3D, MW-36D Y 3 3 3 Y Conservative exhibit a discernable plume. Boron is mapped as primary COI migration indicator parameter for transition zone and bedrock groundwater for CAP evaluation. Bedrock 50 50 <50 2,492 3.6 6 GPMW-1BR, GPMW-2BR, MW-1BR, MW-22BR, MW-34BR, MW-36BR 6 6 6 Y Shallow NE NE NE 0.026 NA 0 NA 0 0 N Chromium (Hexavalent) 10 (pg/L) <0.025 - 13.1 0.03 - 12 N Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 17 12 1.60 - 13.1 0.42 0.04 0 0 0 0 N Bedrock 0.2 1 <0.025 - 1.7 0.98 0.98 0 0 0 0 N Shallow NE NE NE <1 NA 0 NA 0 0 N Chromium (Total) 10 (pg/L) <1 - 42.7 1 - 26 N Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 25 22 1.26 - 42.7 0.654 0.03 0 0 0 0 N Bedrock 4 4 <1 - 9.27 2.6 0.3 0 0 0 0 N Shallow NE NE NE 206 0.7 0 NA 0 0 N Iron 300 (pg/L) <10 - 6220 56.3 - 37500 Y Variable Single location (GPMW-2D) with mean greater than background value and does not exhibit a discernable plume. Boron reported less than reporting limit at GPMW-2D. Does not warrant corrective action. Transition Zone 1210 1293 12 - 1760 96,840 80.0 1 GPMW-2D 1 1 1 Y Bedrock 4227 5130 <10 - 6220 2,225 0.4 0 0 0 0 N Shallow NE NE NE 3,232 64.6 1 GPMW-1S NA 1 0 Y GPMW-3D and MW-22D within Site -specific background range. GPMW-2D with mean greater than Site - Manganese 50 (pg/L) Transition Zone 405 260 <5 - 820 <5 - 1510 7 - 9170 9,604 36.9 3 GPMW-2D, GPMW-3D, MW-22D Y 2 1 1 Y Variable specific and piedmont background range; does not exhibit a discernable plume. Boron reported less than reporting limit at GPMW-2D. Does not warrant corrective action. Bedrock 1198 1773 <5 - 1510 1,480 0.83 0 0 0 0 N Shallow NE NE NE <1 NA 0 NA 0 0 N Mean concentrations greater than 02L north of the EAB along the compliance boundary. Area which Selenium 20 (pg/L) Transition Zone 2 2 <1 - 3.57 <1 - 3.57 0.5 - 2.4 57.8 2.9 4 GPMW-3D, MW-22D, MW-34D, MW-36D N 4 4 4 Y Variable exhibits a discernable plume is limited and within COI -affected groundwater plume depicted for conservative constituents. Bedrock 1 1 <1 - 1.19 9.1 0.46 0 0 0 0 N Shallow NE NE NE 1,186 4.7 1 GPMW-1S NA 1 1 Y Sulfate 250 (mg/I) 0.18 - 77 1.2 - 510 Y Conservative Multiple locations with means greater than 02L near or beyond the compliance boundary and which exhibit a discernable plume. Transition Zone 37 38 11 - 48.1 1,300 5.2 6 GPMW-SD, GPMW-2D, GPMW-3D, MW-22D, MW-34D, MW-36D 6 6 5 Y Bedrock 74 69 0.18 - 77 1,140 4.6 7 GPMW-1BR, GPMW-2BR, GPMW-3BR, MW-22BR, MW-27BR, MW-34BR, MW-36BR 7 7 5 Y Shallow NE NE NE 1,760 3.5 1 GPMW-SS NA 1 1 Y Total Dissolved Solids 500 m I ( g/) <170 - 820 50 - 1200 Y Conservative Multiple locations with means greater than 02L near or beyond the compliance boundary and which exhibit a discernable plume. Transition Zone 540 710 248 - 750 2,000 2.8 6 GPMW-1D, GPMW-2D, GPMW-3D, MW-22D, MW-34D, MW-36D 6 6 5 Y GPMW-1BR, GPMW-2BR, GPMW-3BR, MW-1BR, Bedrock 530 560 170 - 820 1,980 3.5 10 MW-1BRL, MW-22BR, MW-25BR, MW-27BR, 5 5 3 Y MW-34BR, MW-36BR Rev. 1 23 April 2020 P e1of2 TABLE 6-6 COI MANAGEMENT MATRIX - EAST ASH BASIN CORRECTIVE ACTION PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Number of 02LorIMAC Groundwater Roxboro Steam Roxboro Steam Piedmont Maximum Mean Wells Above ncentration Constituents of Zone Statistically Electric Plant Electric Plant Background Co Criterion Groundwater Monitoring Wells with COI Interest' (Reporting Derived Background Value 2,3 Flow Layer Background Range Near or Beyond " , Nearor Concentrations Greater than Comparative Unit) Background Data Dataset Range (All Flow Compliance Beyond of Criteria Set Range (All Flow Zones) Zones) Boundary Compliance Constituent Standards and Values - IMAC Criterion 0 N 0 A W. cc/ a* �o 0 *4 CP V * lb _11 0 10 _KP Q ,� e P 4 0 '. 0-*q �p 'g;;- 0 q , 'o V, C', a* bp 0 �e so F . e,* e� Lines of Evidence (LOE) - IMAC Criterion Rationale for Selection of Cols for Corrective Action Evaluation 11 (constituents where no means are greater than compara ive criteria in all flow zones and/or multiple lines 4P evidence support that constituent occurrences are not related to the source area, no corrective action is warranted) Rationale - IMAC Criterion Shallow NE NE NE <1 NA 0 NA 0 0 N Antimony 1 (pg/L) <1 0.5 - 2.9 N Conservative No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 1 1 <1 <1 NA 0 0 0 0 N Bedrock 1 1 <1 <1 NA 0 0 0 0 N Shallow NE NE NE 10.1 10.1 1 GPMW-1S NA 0 0 Y Cobalt 1 (pg/L) <1 - 21.7 0.088 - 88.85 Y Variable Cobalt concentrations at GPMW-2D, GPMW-3D, and MW-22D within Site -specific background range. Boron reported less than reporting limit at GPMW-2D. Does not warrant corrective action Transition Zone 1 3 < 1 - 4.01 7.2 2.4 3 GPMW-2D, GPMW-3D, MW-22D 3 0 0 Y Bedrock 6 18 < 1- 21.7 5.9 0.3 0 0 0 0 N Shallow NE NE NE 4.9 16.3 1 GPMW-IS NA 0 0 Y MW-13BR and MW-16BR positioned hydraulically upgradient from EAB. Vanadium concentrations at CW-1, Vanadium 0.3 (pg/L) Transition Zone 30 23 0.983 - 24.4 <0.3 - 24.4 0.33 - 25.8 10.8 0.5 0 N 0 0 0 N Non -Conservative MW-1BR, MW-13BR, and MW-16BR within Site -specific background range. Does not warrant corrective action Bedrock 2 3 <0.3 - 3.03 23.2 7.7 4 CW-1, MW-IBR, MW-13BR, MW-36BR 4 0 0 Y 110- Constituent Standards and Values - Background Criterion Lines of Evidence (LOE) - Background Criterion Rationale - Background Criterion Shallow NE NE NE <1 NA NA NA 0 0 N Molybdenum y NE (pg/L) <1 - 24.3 0.5 - 26.2 Y Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 4 8 < 1 - 9.9 2.4 0.3 0 0 0 0 N Bedrock 35 22 < 1 - 24.3 6.6 0.3 0 0 0 0 N Shallow NE NE NE 2,482 NA NA GPMW-IS NA 1 1 Y Strontium NE (pg/L) 64 - 782 27 - 2,120 Y Variable Mean concentrations greater than 02L north of the EAB along the compliance boundary. Area which exhibits a discernable plume is limited and within COI -affected groundwater plume depicted for conservative constituents. Transition Zone 760 760 221 - 782 1,670 2.2 5 GPMW-1D, GPMW-2D, GPMW-3D, MW-22D, MW-36D 5 0 0 Y CW-1, GPMW-1BR, GPMW-2BR, GPMW-3BR, I Bedrock 232 438 64 - 615 1,290 2.9 10 MW-1BR, MW-17BR, MW-22BR, MW-25BR, 7 6 0 Y MW-34BR, MW-36BR Shallow NE NE NE NA NA NA NA 0 0 N Uranium (Total) NE (pg/mL) <0.0002 - 0.00605 0.0002 - 0.864 Y Non -Conservative No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. i Transition Zone 0.005 0.004 <0.0002 - 0.00381 0.004 1.0 0 0 0 0 N Bedrock 0.003 0.006 <0.0002 - 0.00605 0.0105 1.8 2 MW-34BR, MW-36BR 0 0 0 Y Notes: 0 - Reference Criterion 0 - Evidence supports inclusion - Evidence supports exclusion - Constituent list reflects the constituents of interest identified in the 2017 CSA Update (SynTerra, 2017). 2 - Background values were calculated using data from background groundwater samples collected November 2010 to January 2017. 3 - Updated background values were calculated using data from background groundwater samples collected November 2010 to November 2018. 4 - The exceedance ratio is the ratio of the observed constituent concentration divided by the reference criterion. 3 - Assignment of conservative, non -conservative, or variable behavior is based on geochemical modeling results. < - less than Notes: APW - ash pore water COI - constituent of interest CSA - Comprehensive Site Assessment pg/L - micrograms per liter mg/L - milligrams per liter NA - Not Applicable NE - Not Established Y - Yes N - No Prepared by: KTL Checked by: TAW Rev. 1 23 April 2020 I TABLE 6-20 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - WEST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. pg/L pg/L lag/L pg/L lag/L lag/L lag/L lag/L lag/L pg/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 -7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)z 6.3 -7.6 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8-8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID Flow Zone Mean Result3 Background LocationS4 BG-01 Transition 6.4 < 1 < 50 2.8 3.2 < 1 61.5 < 5 < 1 < 1 458 17.2 334 0.00055 18.3 BG-01BR Bedrock 6.9 < 1 < 50 0.1 1.2 < 1 53.3 224 2.3 < 1 177 17.6 310 0.00082 2.1 BG-02BR Bedrock 8.1 < 1 < 50 0.0 1.6 < 1 97.2 49.5 12.7 < 1 262 33.0 322 0.0031 0.35 CCR-112BR-BG Bedrock 6.4 < 1 < 50 - < 1 < 1 - - 7.3 < 1 - 19.0 193 - - MW-10BR Bedrock 6.9 < 1 < 50 0.2 < 1 14.6 11.5 187 11.0 < 1 173 39.6 330 0.0026 2.9 MW-14BR Bedrock 7.2 < 1 < 50 < 0.025 1.1 3.1 1530 360 2.7 < 1 181 12.8 362 0.00025 0.28 MW-15BR Bedrock 7.6 < 1 < 50 0.1 < 1 < 1 579 35.6 11.0 < 1 124 32.0 345 0.00067 0.27 MW-15D Transition 6.6 < 1 < 50 3.0 2.9 < 1 40.0 < 5 < 1 < 1 236 29.3 398 0.00066 10.0 MW-18BR Bedrock 7.9 < 1 < 50 < 0.025 < 1 1.3 1140 777 3.7 < 1 473 12.4 505 0.00048 < 0.3 MW-18D Transition 7.0 < 1 < 50 7.3 6.8 < 1 112 52.0 2.7 < 1 652 32.1 579 0.0031 1.3 MW-19BRL Bedrock 7.0 < 1 < 50 < 0.025 < 1 < 1 3928 1454 2.9 < 1 252 18.0 466 < 0.0002 0.35 MW-26BR Bedrock 7.2 < 1 < 50 < 0.025 < 1 < 1 1950 542 15.4 < 1 259 66.8 512 - 0.32 MW-29BR Bedrock 7.3 < 1 < 50 0.05 < 1 < 1 274 110 2.1 < 1 152 12.2 280 - 0.40 MW-30BR Bedrock 6.9 < 1 < 50 < 0.025 < 1 < 1 2174 1074 4.8 < 1 301 62.7 477 - 0.25 Near or Within the Waste Boundary Locations ABMW-01 Ash Pore Water 9.3 4.0 12380 0.097 < 1 < 1 11.2 < 5 2206 5.0 2062 186 388 < 0.0002 2.0 ABMW-01BR Bedrock 6.9 < 1 552 0.040 < 1 < 1 1606 1004 2.5 < 1 178 19.8 342 < 0.0002 < 0.3 ABMW-02 Ash Pore Water 7.8 < 1 4638 < 0.025 < 1 < 1 2956 747 231 1.1 960 33.2 232 0.00045 1.8 ABMW-02BR Bedrock 7.9 < 1 < 50 0.034 < 1 < 1 568 1154 8.8 < 1 537 83.4 426 0.00058 0.38 ABMW-03 Ash Pore Water 3.5 < 1 255 < 0.025 4.5 127 7514 7824 < 1 1.3 910 1642 1344 - 2.2 ABMW-03BR Bedrock 5.5 < 1 3096 < 0.025 < 1 185 7728 19760 < 1 < 1 1782 2560 3720 - 2.3 ABMW-03BRL Bedrock 7.7 < 1 < 50 < 0.025 < 1 < 1 442 37.5 1.8 < 1 818 496 866 - < 0.3 CCR-200BR Bedrock 6.9 < 1 < 50 - < 1 < 1 - - 1.4 < 1 - 43.8 383 - - CCR-201BR Bedrock 6.1 < 1 < 50 - < 1 17.1 - - 2.2 < 1 - 3675 5675 - - CCR-202BR Bedrock 6.4 < 1 2732 < 0.025 < 1 < 1 < 10 93 1.1 < 1 1190 2380 2780 0.0086 4.1 CCR-202D Transition 6.3 < 1 2716 < 0.025 < 1 < 1 7.0 634 < 1 < 1 1400 2060 3100 0.0092 4.8 CCR-203BR Bedrock 6.6 < 1 718 < 0.025 < 1 8.0 178 355 5.1 < 1 682 426 910 0.0067 3.4 CCR-203D4 Transition 6.5 < 1 505 - < 1 4.9 - - 0.723 j < 1 - 340 790 - - CCR-203S Shallow 6.2 < 1 < 50 - < 1 41.3 - - < 1 < 1 - 8.2 710 - - CCR-204BR Bedrock 6.8 < 1 6323 - < 1 1.3 - - 1.8 < 1 - 310 3175 - - CCR-205BR Bedrock 6.3 < 1 5615 - < 1 < 1 - - 0.78 1.5 - 118 2675 - - CCR-206BR4 Bedrock 6.0 0.981 j 12100 - 4.65 27.8 - - 1.19 < 1 - 230 3200 - - CCR-206S Shallow 6.7 < 1 23725 - < 1 5.1 - - 1.2 < 1 - 348 1725 - - CCR-207BR Bedrock 6.4 < 1 18900 - < 1 26.6 - - 1.5 < 1 - 380 4450 - - CCR-207S Shallow 6.5 < 1 18958 - 1.1 1.8 - - 225 < 1 - 350 3050 - - CCR-208BR Bedrock 6.1 < 1 49700 0.2 5.0 36.7 5.6 7770 213 < 1 9370 1006 7220 0.0086 11.4 CCR-208S Shallow 6.1 < 1 35800 - < 1 7.1 - 124 < 1 - 908 4525 - CCR-209BR Bedrock 6.6 < 1 4328 - < 1 15.1 - 61.9 < 1 - 24.8 705 - Rev. 1 23 April 2020 Page 1 of 3 TABLE 6-20 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - WEST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. pg/L pg/L lag/L pg/L lag/L lag/L lag/L lag/L lag/L pg/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 -7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)z 6.3 -7.6 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8 - 8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID Flow Zone Mean Result3 Near or Within the Waste Boundary Locations (Continued) CCR-209S Shallow 6.7 < 1 3635 - < 1 < 1 2.0 < 1 - 23.8 818 - - CCR-210BR Bedrock 6.5 < 1 2513 - < 1 3.3 24.0 < 1 - 7.9 455 - - CCR-210S Shallow 6.7 < 1 936 - < 1 2.5 9.6 < 1 - 10.8 398 - - CCR-211BR Bedrock 6.3 < 1 1963 - < 1 1.2 4.9 < 1 - 42.5 365 - - CCR-211S Shallow 6.5 < 1 3148 - < 1 6.6 21.8 < 1 - 48.8 480 - - CCR-212BR Bedrock 5.9 < 1 < 50 - 1.8 < 1 - 0.79 < 1 - 38 270 - - CCR-213BR Bedrock 6.4 < 1 < 50 - < 1 < 1 - - < 1 < 1 - 50.3 793 - - CCR-214BR Bedrock 7.0 < 1 < 50 - < 1 < 1 - - 1.5 < 1 - 53.3 425 - - CCR-215BR Bedrock 6.8 < 1 < 50 - < 1 < 1 - - 9.0 < 1 - 54.5 408 - - CCR-216BR Bedrock 6.6 < 1 < 50 - < 1 < 1 - - 1.1 1.0 - 43 440 - - CCR-217BR Bedrock 6.6 < 1 < 50 - < 1 < 1 - - 2.5 0.63 - 44.8 378 - - CCR-218BR Bedrock 6.5 < 1 < 50 - < 1 < 1 - - 2.7 < 1 - 44.3 340 - - CW-034 Transition 5.6 < 1 < 50 - < 5 < 1 377 130 < 1 < 1 287 52 290 - 2.12 CW-03D Bedrock 7.4 < 1 < 50 0.10 < 1 < 1 44.3 27.2 2.9 < 1 277 32.5 343 - 2.5 CW-04 Transition 6.6 < 1 < 50 0.25 < 1 < 1 23.6 < 5 5.9 < 1 189 38.8 342 - 2.3 MW-02 Shallow 6.0 < 1 3336 0.11 1.1 1.0 127 69.6 < 1 < 1 2414 209 2488 0.0043 5.0 HWMW-01BR4 Bedrock 7.3 < 1 28.152 j 0.04 0.392 j < 1 240 70 2.06 < 1 361 140 475 0.000956 0.205 j MW-04BR Bedrock 7.6 < 1 < 50 0.045 < 1 < 1 263 71.2 6.4 < 1 279 32.4 282 - 0.51 MW-12BR Bedrock 7.2 < 1 < 50 < 0.025 < 1 12.6 3064 1220 5.3 < 1 247 37.4 432 - 0.31 MW-205BRL4 Bedrock 6.7 < 1 6350 0.03 0.336 j 3.3 84 1860 2.13 < 1 687 100 1960 0.000444 0.693 MW-205BRLL4 Bedrock 6.9 < 1 7860 <0.025 P4 < 1 0.338 j 3810 1620 2.22 < 1 914 290 2510 0.00411 0.368 MW-205BRLLL4 Bedrock 7.2 1.9 17900 <0.025 P4 4.97 1.25 7120 2940 1.29 < 1 2660 580 4730 0.0078 0.669 MW-208BRL4 Bedrock 7.5 < 1 678 0.031 < 1 0.463 j 1060 402 4.15 < 1 448 150 703 0.000688 0.411 MW-208BRLL4 Bedrock 7.9 < 1 1850 <0.025 1.54 < 1 333 785 1.99 < 1 627 160 1440 0.000195 j 0.264 j MW-208BRLLL4 Bedrock 7.3 < 1 1390 0.034 0.469 j < 1 480 901 1.27 < 1 1340 730 2190 0.00652 0.848 Near or Beyond the Compliance Boundary Locations BG-01BRLR Bedrock 8.3 < 1 < 50 0.069 1.1 < 1 84.3 192 21.6 < 1 647 92.5 475 0.020 0.61 CW-02 Transition 6.6 < 1 < 50 0.24 < 1 < 1 420 118 < 1 < 1 386 79.7 430 0.0020 23.2 CW-02D Bedrock 6.6 < 1 < 50 0.42 < 1 < 1 10.0 < 5 < 1 < 1 324 130 416 0.0014 13.0 CW-05 Transition 6.5 < 1 246 0.32 < 1 < 1 10.3 < 5 < 1 < 1 284 172 432 0.00025 27.7 MW-05BR Bedrock 7.2 < 1 51.8 < 0.025 < 1 5.7 456 363 1.9 < 1 306 222 536 0.0049 0.75 MW-05D Transition 6.5 < 1 687 0.90 0.97 < 1 11.2 10.0 4.3 < 1 402 382 654 0.00035 14.1 MW-06BR4 Bedrock 7.4 < 1 < 50 < 0.025 0.396 j < 1 294 78 0.844 j < 1 164 21 240 0.000392 0.159 j MW-06D4 Transition 6.6 < 1 < 50 0.035 0.383 j < 1 7.296 j 3.533 j 0.246 j 0.506 j 166 33 210 0.000212 6.01 MW-07BR Bedrock 7.1 < 1 < 50 0.14 < 1 < 1 56.3 26.4 1.9 < 1 107 25.2 208 - 13.5 MW-08BR Bedrock 7.2 < 1 < 50 < 0.025 0.91 < 1 1828 757 2.3 < 1 216 26.3 382 - 0.53 MW-09BR Bedrock 6.5 < 1 < 50 < 0.025 < 1 1.1 126 127 0.74 < 1 221 23.5 227 0.00025 5.8 MW-31BR Bedrock 6.9 < 1 < 50 0.060 1.2 < 1 35.5 338 0.94 1.7 326 34.8 392 - 2.4 Rev. 1 23 April 2020 Page 2 of 3 TABLE 6-20 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO APRIL 2019 - WEST ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Analytical Parameters pH Antimony Boron Chromium (VI) Chromium Cobalt Iron Manganese Molybdenum Selenium Strontium Sulfate Total Dissolved Solids Total Uranium Vanadium Reporting Units S.U. pg/L pg/L lag/L pg/L lag/L lag/L lag/L lag/L pg/L pg/L mg/L mg/L pg/mL pg/L 15A NCAC 02L Standard 6.5 - 8.5 1* 700 10 10 1* 300 50 NE 20 NE 250 500 NE 0.3* 2017 Background Threshold Values (Transition Flow Zone)' 6.3 -7.6 1 50 17 25 1 1210 405 4 2 760 37 540 0.005 30 2019 Background Threshold Values (Transition Flow Zone)z 6.3 -7.6 1 50 12 22 3 1293 260 8 2 760 38 710 0.004 23 2019 BTVs Data Set Range (Transition Flow Zone )2 6.3 - 7.6 < 1 - < 1 < 50 - < 50 1.60 - 13.1 1.26 - 42.7 < 1 - 4.01 12 - 1760 <5 - 820 < 1 - 9.9 < 1 - 3.57 221 - 782 11 - 48.1 248 - 750 <0.0002 - 0.00381 0.983 - 24.4 2017 Background Threshold Values (Bedrock Flow Zone)' 6.8 - 8.3 1 50 0.2 4 6 4227 1198 35 1 232 74 530 0.003 2 2019 Background Threshold Values (Bedrock Flow Zone)z 6.1 - 8.3 1 50 1 4 18 5130 1773 22 1 438 69 560 0.006 3 2019 BTVs Data Set Range (Bedrock Flow Zone )2 6.1 - 8.3 < 1 - < 1 < 50 - < 50 <0.025 - 1.7 < 1 - 9.27 < 1 - 21.7 < 10 - 6220 <5 - 1510 < 1 - 24.3 < 1 - 1.19 64 - 615 0.18 - 77 170 - 820 <0.0002 - 0.00605 <0.3 - 3.03 Sample ID Flow Zone Mean Result3 Near or Beyond the Compliance Boundary Locations (Continued) MW-32BR Bedrock 7.6 < 1 < 50 0.045 1.3 < 1 356 139 2.3 < 1 635 350 678 - 0.34 MW-33BR Bedrock 12.4 - < 50 - - - - - - - - - - - - MW-39BR4 Bedrock 8.5 0.492 j < 50 0.64 1.68 B2 < 1 13 62 2.24 < 1 367 30 310 0.00365 1.05 MW-39D4 Transition 6.1 5.63 < 50 0.085 0.629 j,B2 0.648 j 45 65 0.512 j < 1 103 25 200 0.0000761 j 1.44 Notes: ' - Background threshold values were calculated using data from background groundwater samples collected November 2010 to January 2017. z - Background threshold values were calculated using data from background groundwater samples collected November 2010 to Nobember 2018. 3 Statistical mean calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. 4 - Wells with datasets containing fewer than four valid results, the most recent valid sample data up to June 2019 was used. Mean values have been rounded to similar levels of precision as 15A North Carolina Administrative Code (NCAC) 02L Standard or Interim Maximum Allowable Concentration (IMAC). Background values have not been established for the shallow flow zone at this time, therefore, data sets are compared to transitional flow zone criteria for comparison purposes only. Mean or geomean results were used based on the central tendency of the data set. 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 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) i� 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 within range of background threshold values for constituents where there is no regulatory standard, or background threshold values are greater than 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 BTVs - Background Threshold Values B2 - Target analyte was detected in blank(s) at a concentration greater than 1/2 the reporting limit but less than the reporting limit. Analyte concentration in sample is valid and may be used for compliance purposes. COIs - Constituents of Interests j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. NE - not established mg/L - milligrams per liter NTUs - Nephelometric Turbidity Units pCi/L - picocuries per liter P4 - Sample field preservation does not meet EPA or method recommendations for this analysis. pg/mL - micrograms per milliliter pg/L - micrograms per liter RO - The data are unusable. The sample results are rejected due to serious deficiencies in meeting QC criteria. The analyte may or may not be present in the sample. S.U. standard unit Prepared by: KTL Checked by: TAW Rev. 1 23 April 2020 Page 3 of 3 TABLE 6-21 COI MANAGEMENT MATRIX - WEST ASH BASIN CORRECTIVE ACTION PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC Constituent Standards and Values - 02L Criterion Lines of Evidence (LOE) - 02L Criterion Rationale - 02L Criterion Shallow NE NE NE NA NA NA NA NA NA NA NA Boron is not present at concentrations above COI criterion in transition zone or bedrock groundwater near or Boron 700 (pg/L) Transition Zone 50 50 <50 <50 50 - 176.8 687 0.98 0 Y 0 0 0 N Conservative beyond compliance boundary. Boron is mapped as primary COI migration indicator parameter for transition zone and bedrock groundwater for CAP evaluation. Plume -like distribution within compliance boundary. Bedrock 50 50 <50 51.8 0.07 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA Chromium (Hexavalent) 10 (pg/L) <0.025 - 13.1 0.03 - 12 Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 17 12 . 160 - 13.1 0.90 0.07 0 N 0 0 0 N Bedrock 0.2 1 <0.025 - 1.7 0.64 0.64 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA (Total) Chromium Total 10 (pg/L) <1 - 42.7 1 - 26 N Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 25 22 1.26 - 42.7 0.97 0.04 0 0 0 0 N Bedrock 4 4 <1 - 9.27 1.68 B2 0.17 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA Iron 300 (pg/L) <10 - 6220 56.3 - 37500 Y Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 1210 1293 12- 1760 420 0.32 0 0 0 0 N Bedrock 4227 5130 <10 - 6220 1828 0.36 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA Manganese 50 (pg/L) <5 - 1510 7 - 9170 Y Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrantcorrective action. Transition Zone 405 260 <5 - 820 130 0.50 0 0 0 0 N Bedrock 1198 1773 <5 - 1510 757 0.43 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA Selenium 20 (Ng/L) <1 - 3.57 0.5 - 2.4 N Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 2 2 <1 - 3.57 0.506 j 0.03 0 0 0 0 N Bedrock 1 1 <1 - 1.19 1.7 0.09 0 0 0 0 N Shallow NE NE NE NA NA NA NA NA NA NA NA Plume -like distribution of sulfate coincident with boron within ash WAB waste boundary and at transition zone well MW-05D (associated with decommissioned sluice line). Boron is not present at concentrations above COI Sulfate 250 (mg/1) Transition Zone 37 38 11 - 48.1 0.18 - 77 1.2 - 510 382 1.53 1 MW-513 Y 1 1 0 Y Conservative criterion near or beyond compliance boundary. Isolated detection of sulfate above COI criterion at hydraulically upgradient bedrock well MW-32BR. Boron is not detected in groundwater at MW-32BR.. Does not warrant corrective action. Bedrock 74 69 0.18 - 77 350 1.4 1 MW-32BR 1 1 0 Y Shallow NE NE NE NA NA NA NA NA NA NA NA Plume -like distribution of TDS coincident with boron within WAB waste boundary and at transition zone well Transition Zone 540 710 248 - 750 654 0.92 0 0 0 0 y Total Dissolved Solids 500 (mg/1) <170 - 820 50- 1200 Y Conservative MW-05D (associated with decommissioned sluice line). Boron is not present at concentrations above COI criterion near or beyond compliance boundary. Isolated detection of TDS above COI criterion at hydraulically upgradient bedrock well MW-32BR. Boron is not detected in groundwater at MW-32BR.. Does not warrant corrective action. Bedrock 530 560 170 - 820 678 1.21 1 MW-32BR 0 0 0 Y Rev. 1 23 April 2020 Pagel°f2 TABLE 6-21 COI MANAGEMENT MATRIX - WEST ASH BASIN CORRECTIVE ACTION PLAN UPDATE ROXBORO STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, SEMORA, NC MAE Constituent Standards and Values - IMAC Criterion EL Lines of Evidence (LOE) - IMAC Criterion Rationale - IMAC Criterion Antimony 1 (Ng/L) Shallow NE NE NE <1 0.5 - 2.9 NA NA NA NA N NA NA NA NA Conservative One mean is greater than comparative criteria associated with newly installed MW-39D positioned upgradient at compliance boundary. Not positioned within conservative group plume. Does not warrant corrective action. Transition Zone 1 1 <1 5.63 5.63 1 MW-39D 1 1 1 Y Bedrock 1 1 <1 0.492j 0.49 0 0 0 0 N Cobalt 1 (pg/L) Shallow NE NE NE <1 - 21.7 0.088 - 88.85 NA NA NA NA Y NA NA NA NA Variable No means greater than comparison criteria near or beyond the compliance boundary. Does not warrantcorrective action. Transition Zone 1 3 < 1 - 4.01 0.648 j 0.22 0 0 0 0 N Bedrock 6 18 < 1- 21.7 5.7 0.32 0 0 0 0 N Vanadium 0.3 (pg/L) Shallow NE NE NE <0.3 - 24.4 0.33 - 25.8 NA NA NA NA NA NA NA NA Non -Conservative MW-7BR positioned upgradient and CW-2D and MW-9BR positioned downgradient. Not positioned within conservative group plume. Transition Zone 30 23 0.983 - 24.4 27.7 1.20 0 0 0 0 N Bedrock 2 3 <0.3 - 3.03 13.5 4.49 3 CW-2D, MW-7BR, MW-9BR 3 0 0 Y Molybdenum y NE (pg/L) Shallow NE NE Constituent Standards NE and Values - <1 - 24.3 Background Criterion 0.5 - 26.2 NA NA NA NA Y NA NA ckgrouI NA Criterion NA Variable Rationale - Background Criterion No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 4 8 < 1 - 9.9 4.3 0.54 0 0 0 0 N Bedrock 35 22 < 1 - 24.3 6.4 0.29 0 0 0 0 N Strontium NE (pg/L) Shallow NE NE NE 64 - 782 27 - 2,120 NA NA NA NA Y NA NA NA NA Variable Boron is not present at concentrations above COI criterion near or beyond compliance boundary. Isolated detections of strontium greater than background at hydraulically upgradient wells BG-1BRLRL and MW-32BR. Boron is not detected in groundwater at BR-IBRLR and MW-32BR.. Does not warrant corrective action. Transition Zone 760 760 221 - 782 402 0.53 0 0 0 0 N Bedrock 232 438 64 - 615 647 1.48 2 BG-1BRLR, MW-32BR 2 0 0 Y Uranium (Total) NE (pg/mL) Shallow NE NE NE 0.0002 - 0.00605 0.0002 - 0.864 NA NA NA NA Y NA NA NA NA Non -Conservative No means greater than comparison criteria near or beyond the compliance boundary. Does not warrant corrective action. Transition Zone 0.005 0.004 <0.0002 - 0.00381 0.0020 0.49 0 0 0 0 Bedrock 0.003 0.006 <0.0002 - 0.00605 0.020 3.33 1 BG-1BRLR 0 0 0 N Notes: 0- Reference Criterion 0- Evidence supports inclusion �- Evidence supports exclusion ' - Constituent list refl,= the constituents of interest identified in the 2017 CSA Update (SynTerre, 2017). ' - Background values were calculated using data from background groundwater samples collected November 2010 to January 2017. - Updated background values were calculated using data from background groundwater samples collected November 2010 to November 2018. ° - The excesdance ratio Is the ratio of the observed constituent concentration divided by the reference criterion. - Assignment of conservative, non -conservative, or variable behavior is based on geochemical modeling results. < - less than N2t- APW - ash pare water C0] - constituent of Interest CSA - Comprehensive Site Assessment pg/L- micrograms per liter mg/L - milligrams per liter NA - Not Applicable NE - Net Established Y - Yes N - No Prepared by: UL Checked by: ALL Rev. 1 23 April 2020 l