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HomeMy WebLinkAboutBUCK - GW BTV MEMO FINAL (3)Lip synTerra TECHNICAL MEMORANDUM Date: September 5, 2017 File: 1026.16 To: Bristol Grohol (Duke Energy) Cc: Kathy Webb (SynTerra) From: Perry Waldrep (SynTerra) r Subject: Background Threshold Values f GrounBuck Combined Cycle Station- Salisbury, An updated background groundwater dataset was provided to the North Carolina Department of Environmental Quality (NCDEQ) for Buck Combined Cycle Station (Buck) on May 26, 2017. Additionally, the revised Statistical Methods for Developing Reference Background Concentrations for Groundwater and Soil at Coal Ash Facilities (statistical methods document) (HDR Engineering, Inc. and SynTerra Corporation, May 2017) was provided to NCDEQ. On July 7, 2017, NCDEQ provided a response letter (Zimmerman to Draovitch, July 7, 2017) for each Duke Energy coal ash facility that identified soil and groundwater data appropriate for inclusion in the statistical analysis to determine background threshold values (BTVs) for both media. As outlined in the NCDEQ July 7, 2017 letter, Duke Energy is required to provide BTVs for both media within 60 days from receipt of the NCDEQ letter for facilities submitting Comprehensive Site Assessments (CSAs) later than October 31, 2017. BTVs for soil are provided under separate cover. The revised background groundwater dataset provided to NCDEQ on May 26, 2017 addressed comments provided in a letter by NCDEQ (Zimmerman to Draovitch, April 28, 2017). NCDEQ requested Duke Energy collect at least 10, rather than the previously planned eight, valid samples from background monitoring wells prior to determination of BTVs for constituents within each flow system. For groundwater datasets with less than 10 valid samples available for determination of BTVs, no formal upper tolerance limit (UTL) statistics could be run and the provisional BTV (PBTV) for a constituent and groundwater flow system was computed to be either: y The highest value, or y If the highest value is above an order of magnitude greater than the geometric mean of all values, then the highest value should be considered an outlier and removed from further use and the PBTV is computed to be the second highest value. P:\Duke Energy Carolinas\ Statistics_CAMA \Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO \ Buck \ Groundwater \ BUCK - GW BTV MEMO_FINAL.docx Background Threshold Values for Groundwater September 5, 2017 Buck Combined Cycle Station Page 2 of 5 NCDEQ requested that the updated background groundwater dataset exclude data from the background data set due to one or more of the following conditions: 7 Sample pH is greater than or equal to 8.5 standard units (S.U.) unless the regional DEQ office has determined an alternate background threshold pH for the site; i7 Sample turbidity is greater than 10 Nephelometric Turbidity Units (NTUs); 0 Result is a statistical outlier identified for background sample data presented to NCDEQ on May 26,2017; 107 Sample collection occurred less than a minimum 60 days between sampling events; and y Non -detect results are greater than 2LAMAC. Additional site-specific requirements related to background groundwater dataset for Buck as outlined in the July 7, 2017 NCDEQ letter have been incorporated. This technical memorandum summarizes the revised background groundwater datasets and statistically determined BTVs. Statistical determinations of BTVs were performed in accordance with the revised Statistical Methods for Developing Reference Background Concentrations for Groundwater and Soil at Coal Ash Facilities (statistical methods document) (HDR Engineering, Inc. and SynTerra Corporation, May 2017). GROUNDWATER BACKGROUND DATA The current background monitoring well network consists of wells installed within three flow zones — shallow, deep, and bedrock. Well locations are presented on Figure 1. Background datasets provided to NCDEQ on May 26, 2017 were revised based on input from NCDEQ in the July 7, 2017 letter. Revised background datasets for each flow system used to statistically determine naturally occurring concentrations of inorganic constituents in groundwater are provided in Table 1. The following sections summarize the refined background datasets along with results of statistical evaluations for determining BTVs. SHALLOW Six wells, BG -1S, BG -2S, BG -3S, MW -6S, GWA-1S and MW -8S monitor background groundwater quality within the shallow flow zone. In the July 7, 2017 letter, NCDEQ concurred with the background locations and samples proposed for the shallow flow zone background dataset with the exception of those samples collected less than 60 days between sampling events, statistical outliers, and invalid data. Those samples were omitted prior to statistical determinations. The resulting shallow background dataset meets the minimum requirement of 10 samples for all constituents. The resulting shallow groundwater background dataset meets the minimum requirement of 10 samples for all constituents and is presented in Table 1. BTVs P:\Duke Energy Carolinas\ Statistics_CAMA \Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO \ Buck \ Groundwater \ BUCK - GW BTV MEMO_FINAL.docx Background Threshold Values for Groundwater September 5, 2017 Buck Combined Cycle Station Page 3 of 5 were calculated for constituents monitored within the shallow flow zone using formal UTL statistics. BTVs for the shallow flow system are provided in Table 2. DEEP FLOW ZONE Two wells —BG -21) and MW -81) — monitor background groundwater quality within the deep flow zone. In the July 7, 2017 letter, NCDEQ recommended removal and reevaluation of BG -11) from the deep background dataset due to a recent re -installation and water quality issues. Samples collected less than 60 days between sampling events, statistical outliers, and invalid data have been omitted from use in statistical determinations. The resulting deep groundwater background dataset meets the minimum requirement of 10 samples for all constituents except hexavalent chromium, nitrate + nitrite, sulfide, and total uranium. Table 1 presents the revised background dataset for the deep flow zone. With the exception of hexavalent chromium, nitrate + nitrite, sulfide, and total uranium, BTVs were calculated using formal UTL statistics. The PBTV for hexavalent chromium, methane, molybdenum, nitrate + nitrite, total organic carbon (TOC), radium, sulfide, and total uranium were computed to be either the highest value, or, if the highest value was above an order of magnitude greater than the geometric mean of all values, the highest value was considered an outlier and removed from from further use and the PBTV was computed to be the second highest value. BTVs and PBTVs are presented in Table 2. BEDROCK Three wells — BG-3BRU, MW -61) and MW-6BR — monitor background groundwater quality within the fractured bedrock. NCDEQ recommended removal and reevaluation of BG-1BR, BG-2BR and MW-8BR from the bedrock dataset due to recent re -installations and water quality issues. Samples collected less than 60 days between sampling events, statistical outliers, and invalid data have been omitted from use in statistical determinations. The fractured bedrock background dataset meets the minimum requirement of 10 samples for all constituents except TOC radium and total uranium. Table 1 presents the revised background dataset for fractured bedrock. With the exception of TOC and total uranium, BTVs were calculated for constituents monitored within fractured bedrock using formal UTL statistics. The PBTV for TOC and total uranium were computed to be either the highest value, or, if the highest value was above an order of magnitude greater than the geometric mean of all values, the highest value was considered an outlier and removed from further use and the PBTV was computed to be the second highest value. PBTVs and BTVs for fractured bedrock are presented in Table 2. LIST OF FIGURES Figure 1 Well Location Map LIST OF TABLES Table 1 Background Groundwater Results Through March 2017 Table 2 Groundwater Background Threshold Values P:\Duke Energy Carolinas\ Statistics_CAMA \Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO \ Buck \ Groundwater \ BUCK - GW BTV MEMO_FINAL.docx Background Threshold Values for Groundwater September 5, 2017 Buck Combined Cycle Station FIGURE P:\Duke Energy Carolinas\ Statistics_CAMA \Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO \ Buck \ Groundwater \ BUCK - GW BTV MEMO_FINAL.docx Background Threshold Values for Groundwater September 5, 2017 Buck Combined Cycle Station TABLES P:\Duke Energy Carolinas\ Statistics_CAMA \Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO \ Buck \ Groundwater \ BUCK - GW BTV MEMO_FINAL.docx TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 1 of 6 Analytical Parameter pH Turbidity Alkalinity Aluminum Antimony Arsenic Barium Beryllium B� carbonate Alkalinity Boron Cadmium Calcium Carbonate Alkalinity Chromium (VI) 1 Chromium Chloride Cobalt Copper Iron Lead Magnesium Manganese Mercury Reporting Units SU NTU ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L 15A NCAC 02L Standard 6.5-8.5 NE NE NE 1 10 700 4 NE 700 2 NE NE 30 30 250000 1 1000 300 15 NE 50 1 Sample ID Sample Collection Date Field Parameter Analytical Results Shallow BG 1S 111-9%20i c C p� T.2 ^�nnn 47900 �,n 8_3G 'T0.5 y ^ , , LTJ n ZT ��� 0.069 j �� 47990 � �p �O-:08 y p� 8620 Cnnn I I 5000 y 9��5 j � nn Z300 c HCl n C 44)-.6 p� 899 O 2S 4020 CA TO �� 9,077 BG -1S 12/10/2015 6.4 4.55 43200 130 < 0.5 U 0.23 J 15 < 0.2 U 43200 < 50 U < 0.08 U 7720 < 5000 U 0.26 1.1 J+ 2200 2.1 0.55 J+ 210 < 0.1 U 3420 530 < 0.2 U BG -1S 3/15/2016 6.11 7.26 41900 176 < 0.5 U 0.17 23.4 0.12 J+ 41900 < 50 U < 0.08 U 9380 < 5000 U 0.22 0.72 3600 0.87 1.1 249 < 0.1 U 4180 160 < 0.2 U BG -1S 6/23/2016 5.7 2.9 43800 116 0.14 J 0.13 24.2 0.023 J 43800 < 50 U < 0.08 U 8740 < 5000 U 0.31 1.2 2600 0.35 0.41 184 0.091 J 4150 148 < 0.2 U BG 15 9/9/2016 6 3.9 54900 108 < 0.5 U 0.13 23.8 0.071 J 54900 < 50 U < 0.08 U 10300 Fs -u 0.14 0.29 J 2400 0.76 0.75 113 < 0.1 U 4830 446 < 0.2 U BG -1S 12/7/2016 5.9 4.5 43200 < 100 U < 0.5 U 0.21 22.3 0.016 J 43200 < 50 U < 0.08 U 7250 < 5000 U 0.57 0.68 1700 1.2 1.9 100 0.1 3310 356 < 0.2 U BG -1S 3/22/2017 5.7 7.4 36600 114 < 0.5 U 0.16 J+ 18.9 0.03 J 36600 < 50 U < 0.08 U 6480 < 5000 U 0.89 1.33+ 1900 J+ 0.36 0.48 J 147 < 0.1 U 3080 71.1 < 0.2 U BG -2S 9/22/2015 5.7 9.4 31700 950 < 0.5 U 0.17 J 46 < 0.2 U 31700 < 50 U < 0.08 U 6120 < 5000 U 2.1 5400 0.84 2.7 760 0.25 4410 47 < 0.2 U BG 2S IV+B/2 5_4 8-.-3 22396 1T0 <^0.5ry < 0.5 y -3yi < 0.2 y 22300 < 50 Y 9$23 47iB < 5000 y §196-OTo 3590 44 <-OTo BG -2S 12/10/2015 5.6 9.15 23100 78 J < 0.5 U < 0.5 U 34 < 0.2 U 23100 < 50 U < 0.08 U 4720 < 5000 U 0.11 J+ 1.5 J+ 5200 0.493 0.373+ 57 < 0.1 U 3500 14 < 0.2 U BG -2S 3/15/2016 5.28 0.29 16500 < 100 U < 0.5 U 0.077 J 40.2 0.063 J+ 16500 < 50 U < 0.08 U 3230 < 5000 U 0.078 0.391 6100 2.6 0.17 J < 50 U < 0.1 U 2570 16.8 < 0.2 U BG -2S 6/23/2016 5 3.8 21100 197 0.14 J 0.13 39.4 0.034 J 21100 < 50 U < 0.08 U 4130 < 5000 U 0.063 0.383 4600 1.1 0.3 J 153 < 0.1 U 3330 12.3 < 0.2 U BG -2S 9/9/2016 5.3 1 20400 145 < 0.5 U 0.11 35.3 < 0.1 U 20400 < 50 U < 0.08 U 4200 < 5 y 0.14 J 4700 0.29 0.43 J 112 < 0.1 U 3360 9.5 < 0.2 U BG -2S 12/8/2016 5.5 7.6 23900 118 < 0.5 U 0.18 37 0.053 J 23900 < 50 U < 0.08 U 4940 < 5000 U 0.13 0.27 J 4900 0.11 1.3 78.4 < 0.1 U 3630 7.6 < 0.2 U BG -2S 3/22/2017 5.3 4.5 23300 78.5 J < 0.5 U 0.14 J+ 37.9 0.021 J 23300 < 50 U < 0.08 U 4590 < 5000 U 0.11 J+ 0.36 J+ 5000 J+ 0.055 J+ 0.63 60.9 < 0.1 U 3660 5.9 < 0.2 U BG -3S 6/12/2015 5.5 9.2 < 10000 UJ 190 < 0.5 UJ < 0.5 UJ 441 0.086 J < 10000 UJ < 50 UJ < 0.08 UJ 1760 <000e U, 1.8 J 1500 J 2.9 J 0.4 J 257 J 0.091 J 7163 443 < 0.2 UJ BG -3S 9/24/2015 5.4 9.9 7700 200 < 0.5 U < 0.5 U 33 < 0.2 U 7700 < 50 U < 0.08 U 1300 < 5000 U 0.78 J+ 1100 2.2 8.8 280 0.093 J 616 23 < 0.2 U BG 3S =1118� -5-r4 9-.$ 6500 20G < 0.5ry < 0.5 y -34 < 0.2 y 65$9 E5$l3 < 0.08 y 3280 <5090 y 0z8 4-1- X499 -17.4 8$23 329 9$7$3 5-74 24 <- 0.2 Y BG -3S 12/10/2015 5.7 7.3 6500 80 J < 0.5 U < 0.5 U 29 < 0.2 U 6500 < 50 U < 0.08 U 1260 < 5000 U 0.18 0.57 1400 1.3 0.98 J 110 0.08 J 533 16 < 0.2 U BG -3S 3/15/2016 5.5 9.8 6100 143 < 0.5 U 0.073 J 27.3 0.0383+ 6100 < 50 U < 0.08 U 1160 < 5000 U 0.18 0.73 J+ 860 J 1.1 0.523+ 244 J+ < 0.1 U 503 13.2 < 0.2 U BG -3S 6/24/2016 5.1 2.2 < 5000 U < 100 U 0.18 J 0.085 J 35.9 0.049 J < 5000 U < 50 U < 0.08 U 1920 < 5000 U 0.96 1600 1.7 0.57 67.6 0.092 J 644 25.3 < 0.2 U BG 35 9/9/2016 5.4 0.3 6300 < 100 U < 0.5 U < 0.1 U 33 0.021 J 6300 < 50 U < 0.08 U 1160 F5 1 0.17 0.8 930 J 1.4 1.2 32.2 J < 0.1 U 571 10.1 < 0.2 U BG -3S 12/7/2016 5.5 3.4 6200 < 100 U < 0.5 U < 0.1 U 28 0.054 J 6200 < 50 U < 0.08 U 1100 < 5000 U 0.19 0.52 830 J 1.4 1.5 80.9 < 0.1 U 456 24.7 < 0.2 U BG -3S 3/21/2017 4.9 2.5 6900 < 100 U < 0.5 U 0.079 J 24.9 0.033 J 6900 < 50 U < 0.08 U 1050 < 5000 U 0.25 0.5J 840 J 0.81 0.48 J+ < 50 U < 0.1 U 487 4.31 0.1 J+ MW -6S 3/7/2011 5.54 8.1 -- -- < 1 U < 1 U 36 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 323 < 1 U -- 100 < 0.05 U MW -6S 7/5/2011 5.09 7.5 -- -- < 1 U < 1 U 40 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 139 < 1 U -- 97 < 0.05 U MW -6S 11/2/2011 5.41 4 -- -- < 1 U < 1 U 36 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 56 < 1 U -- 59 < 0.05 U MW -6S 3/7/2012 5.26 1.63 -- -- < 1 U < 1 U 39 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 185 < 1 U -- 80 < 0.05 U MW -6S 7/3/2012 4.48 5.21 -- -- < 1 U < 1 U 39 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 137 < 1 U -- 114 < 0.05 U MW -6S 11/7/2012 5.24 4.26 8200 -- < 1 U < 1 U 40 -- 8200 < 50 U < 1 U 2250 < 5000 U -- < 5 U -- -- < 5 U 51 < 1 U 2630 60 < 0.05 U MW -6S 3/6/2013 5.13 2.04 14000 < 1 U < 1 U 39 < 50 U < 1 U 2340 < 5 U < 5 U 142 < 1 U 2710 72 < 0.05 U MW -6S 7/8/2013 5.07 4.24 16000 -- < 1 U < 1 U 41 -- -- < 50 U < 1 U 2490 -- -- < 5 U -- -- < 5 U 201 < 1 U 2890 135 < 0.05 U MW -6S 11/4/2013 5.19 3.32 6200 -- < 1 U < 1 U 39 -- -- < 50 U < 1 U 2340 -- -- < 5 U -- -- < 5 U 247 < 1 U 2690 73 < 0.05 U MW -6S 3/3/2014 5.12 1.36 15000 -- < 1 U < 1 U 41 -- -- < 50 U < 1 U 2360 -- -- < 5 U -- -- < 5 U 37 < 1 U 2670 73 < 0.05 U MW -6S 7/1/2014 5.23 5.29 6900 -- < 1 U < 1 U 38 -- -- < 50 U < 1 U 2200 -- -- < 5 U -- -- < 5 U 70 < 1 U 2510 43 < 0.05 U MW -6S 11/3/2014 5.27 8.43 < 5000 U -- < 1 U < 1 U 37 -- -- < 50 U < 1 U 2070 -- -- < 5 U -- -- < 5 U 487 < 1 U 2350 35 < 0.05 U MW -6S 3/4/2015 5.24 6.64 -- -- < 1 < 1 41 -- -- < 50 < 1 2280 -- -- < 5 -- -- < 5 366 < 1 2630 29 < 0.05 raW-6s 6,=30 20=5 9-4 9.27 33208 52-3 9.27 3 < 0. 5 0 4-3 9.978 3 33286 < So y < 0.98 14 2990 F5089 14 - 3.7 3 2896 4049 j 4-690 2920 4-5 < 0.2 o MW -6S 7/6/2015 5.28 0.82 15000 45 < 1 U < 1 U 47 < 1 U 15000 < 50 U < 1 U 2460 < 5000 U -- < 5 U 4400 3.44 < 5 U 55 < 1 U 2990 35 < 0.05 U MW -6S 11/3/2015 5.36 2.32 62900 60 < 1 U < 1 U 42 < 1 U 62900 < 50 U < 1 U 2470 B2 < 5000 U -- < 5 U 4700 3.64 < 5 U 65 < 1 U 2780 41 < 0.05 U raW-6s 12kl*20 5 5 3 3_ 38108 109 o Opo < 0.5 y 44 9$723 38390 < 50 y < 0.68 13 2260 < 5000 l3 9$273 0.75 4686 9:3 2.4 3 1- X300 9.058 3 2968 47.544 OTo MW -6s 3 1,=2&=6 2183 29286 378 2-1-8 < 1 Y §2 < 1 y 26206 <3$l} y 2979 < 5090 3 E 5 13 4406 3i.5 < 5 l3 3389 < 1 Y 36;z9 296 - MW -6S 3/28/2016 5.3 1 17600 < 100 U < 0.5 U 0.092 J 43.3 0.052 J 17600 < 50 U < 0.08 U 2820 < 5000 U < 0.03 U 0.33 J+ 4600 8.1 0.48 J+ 693 0.12 3320 131 < 0.2 U MW -6S 6/28/2016 4.4 1.5 15800 < 100 U < 0.5 U 0.041 J 43.5 0.048 J 15800 < 50 U < 0.08 U 2450 < 5000 U 0.34 0.88 4200 6.9 1.3 385 0.1 2880 111 < 0.2 U tw W -6s 7f5/20'=6 41 3.18 X5486 39 < 1 y < 1 y 4-3 < 1 y 33460 < 50 Y < 1 Y 2358 X88014 Sl3 4206 5.88 < S y 33-5 < 1 l3 2770 99 raW-6s 11,=1,=20'=6 S.27 3.32 14288 29 < 1 y < 1 y 44 < 1 l3 44260 < 50 y < 1 l} 2338 X88014 E 5 if 4366 3-.4 < S 13 7-9 < 1 y 2660 7-6 MW -6S 12/8/2016 5.6 0.88 15100 < 100 U < 0.5 U 0.045 J 40.3 0.08 J 15100 < 50 U < 0.08 U 2380 < 5000 U 0.38 0.53 4400 5.7 0.91 46.2 J < 0.1 U 2690 79.9 < 0.2 U raw -6s 3, 0,=20'=7 t 4-37 4.0 0 33 1 -<-� -<-� 1 45 _l3 44300 -<-� -<- l} 1 2§30 -< 8 - _< - 4700 3-,&8 1F3 if 3-2 '4__6 2$$8 48 P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 1 of 6 TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 2 of 6 Analytical Parameter Methane Molybdenum Nickel Nitrate + Potassium Selenium Sodium Strontium Sulfate Sulfide Thallium Total Dissolved Solids Total Organic Carbon Vanadium Zinc Radium (Total) UraniumNitrite (Total) Reporting Units ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L pCi/L ug/L 15A NCAC 02L Standard NE NE 100 NE NE 20 NE NE 250000 NE 0.2 500000 NE 0.3 1000 NE NE Sample ID Sample Collection Date Analytical Results Shallow BG 1S 14fl%�o+s � -t c TQ �� TJV < 5000 O �O-TIJ �p 7000 c, VS Z609 1 �Z00 y �OTy i'�1 3000 j+ c 1000 Y c i �t A Z74 BG -1S 12/10/2015 2.2 J+ 3-3 1.7 J+ 360 < 5000 U < 0.5 U 7180 49 710 J < 100 U < 0.1 U 64000 J+ 550 J 2.5 15 J+ --- --- BG-1S 3/15/2016 1.7 J+ 0.64 1.3 210 < 5000 U < 0.5 U 6710 62.6 9500 < 100 U < 0.1 U 82000 1200 1.7 4.8 J+ 1.022 0.5 BG -1S 6/23/2016 < lou 0.32J 1.4 73 < 5000 U < 0.5 U 5700 63.2 2100 < 100 U < 0.1 U 150000 -- 1.5 3.8 J 0.3839 0.5 BG -1S 9/9/2016 < lou 0.68 1.9 70 < 5000 U < 0.5 U 7560 71.7 1200 <G. 1 U < 0.1 U 77000 < 1 U 1.4 7 J --- 0.5 BG -1S 12/7/2016 < lou 0.46 J 1.9 150 < 5000 U < 0.5 U 4970 J 61.9 1600 < 100 U < 0.1 U 63000 -- 1.6 8.9 J 0.358 0.5 BG -1S 3/22/2017 < lou 0.45J 1.1 320 < 5000 U < 0.5 U 5950 48.5 1000 < 100 U < 0.1 U 78000 -- 1.9 3.7 J 0.451 0.5 BG -2S 9/22/2015 5.9 J+ < 0.5 U 1.6 20 < 5000 U < 0.5 U < 5000 U 45 1100 < 100 U < 0.1 U 75000 J+ < 1000 U 3 J+ 29 --- --- BG-2S 0.5 v 3.2 X20 Y < 5000 y x--0.5 y E-5999 IJ -3-1- 950 j 100 y x--0.1 Y 77 E 1090 y 0.-73 48 BG -2S 12/10/2015 1.3 J+ < 0.5 U 2J+ 25J+ < 5000 U < 0.5 U < 5000 U 30 580 J < 100 U < 0.1 U < 25000 U < 1000 U 0.42 J 17 J+ --- --- BG-2S 3/15/2016 1.8 J+ < 0.5 U 1.3 15 J < 5000 U < 0.5 U 3360 J 20.1 880 J < 100 U < 0.1 U 39000 < 1000 U 0.29 J 15.3 J+ 0.3396 0.5 BG -2S 6/23/2016 < lou < 0.5 U 0.94 < 20 U < 5000 U < 0.5 U 2640 J 27.4 770 J < 100 U < 0.1 U 170000 -- 0.66 15.7 1.025 0.5 BG -2S 9/9/2016 < lou < 0.5 U 1 16J < 5000 U < 0.5 U 2320 J 27.5 < 1 U < < 0.1 U 32000 < 1 U 0.3 J 17.2 --- 0.5 BG -2S 12/8/2016 < lou < 0.5 U 0.74 12J < 5000 U < 0.5 U 1990 J 34.1 < 1000 U < 100 U 0.038 J < 25000 U -- 0.29 J 21 0.531 0.5 BG -2S 3/22/2017 < lou < 0.5 U 0.76 111 < 5000 U < 0.5 U 2300 J 30.2 < 1000 U < 100 U < 0.1 U 46000 -- 0.51 J+ 17.8 0.1937 0.5 BG -3S 6/12/2015 < 10 UJ 0.12 J 3.2 J 220 J < 5000 UJ < 0.5 UJ 2760 J 22 J 890 J < 100 UJ < 0.1 UJ < 25000 UJ 700 J 0.86 J 29J --- --- BG-3S 9/24/2015 1.5 J+ < 0.5 U 1.7 310 < 5000 U < 0.5 U < 5000 U 17 540 J < 100 U < 0.1 UJ < 25000 U < 1000 U 0.43 J 23 --- --- SG-3S 14fl-8� 1.6-}+ < 0.5 'v' 4�4 3&9 < 55000 y < 0.5 IJ E -.589I} 44 E 1$00 y <i00 y <-9 1 y 66090 < 1000 y 0.67 3 43 BG -3S 12/10/2015 2.1 J+ < 0.5 U 1.2 370 < 5000 U < 0.5 U < 5000 U 15 < 1000 U < 100 U < 0.1 U < 25000 U < 1000 U 0.66 J 17 --- --- BG-3S 3/15/2016 1.8 J+ < 0.5 U 0.94 360 < 5000 U < 0.5 U < 5000 U 14.5 660 J < 100 U < 0.1 U < 25000 U < 1000 U 0.58 J+ 15.4 J+ 0.134 0.5 BG -3S 6/24/2016 < 10 U < 0.5 U 1.7 240 < 5000 U < 0.5 U 1880 J 18.9 < 1000 U < 100 U < 0.1 U 51000 -- 0.6 16 0.585 0.5 BG -3S 9/9/2016 < 10 U < 0.5 U 1.6 280 < 5000 U < 0.5 U 1730 J 16.7 < 1 U < 0.1 U 28000 < 1 U 0.21 J 14 --- 0.5 BG -3S 12/7/2016 < 10 U < 0.5 U 1.9 370 < 5000 U < 0.5 U 1460 J 15.6 < 1000 U < 100 U < 0.1 U 28000 -- 0.34 8.5 J 0.992 0.5 BG -3S 3/21/2017 < 10 U < 0.5 U 0.85 380 < 5000 U < 0.5 U 1720 J 14.6 < 1000 U < 100 U < 0.1 U 28000 0.37 J+ 3.2 J 0.088 0.5 MW -6S 3/7/2011 -- -- 7 -- -- < 1 U -- -- 190 -- -- 32000 -- -- 9 --- --- MW-6S 7/5/2011 -- -- 7 -- -- < 1 U -- -- 190 -- -- 39000 -- -- 7 --- MW-6S 11/2/2011 -- -- 7 -- -- < 1 U -- -- 260 -- -- 21000 -- -- 6 --- --- MW-6S 3/7/2012 -- -- 6 -- -- < 1 U -- -- 180 -- -- 33000 -- -- 8 --- --- MW-6S 7/3/2012 8 -- < 1 U -- 200 < 250000 U 7 --- --- MW-6S 11/7/2012 -- -- 7 -- 532 < 1 U 2630 -- 200 -- -- 38000 -- -- 7 --- --- MW-6S 3/6/2013 7 512 < 1 U 2570 210 47000 8 --- MW-6S 7/8/2013 -- -- 7 -- 525 < 1 U 2690 -- 250 -- -- 63000 -- -- 10 --- --- MW-6S 11/4/2013 -- -- 7 -- 479 < 1 U 2570 -- 240 -- -- 50000 -- -- < 5 U --- --- MW-6S 3/3/2014 -- -- 7 -- 511 < 1 U 2570 -- 160 -- -- 36000 -- -- 14 --- --- MW-6S 7/1/2014 -- -- 6 -- 498 < 1 U 2380 -- 140 -- -- 32000 -- -- < 5 U --- --- MW-6S 11/3/2014 -- -- 7 -- 510 < 1 U 2380 -- 140 -- -- 39000 -- -- 11 --- --- MW-6S 3/4/2015 -- -- 7 -- 530 < 1 2420 -- 150 -- < 0.2 36000 -- -- 10 --- --- �iw 6S 3W2-9 = 50.8 < 0.5 y 6-:4 2-7-9 < 3$90 y < 0.5 y 255$3 -$ 670 3 tel-} 8$3 3 34$88 X089 11 8. :3 3 8-�-+ MW -6S 7/6/2015 -- < 1 U 6 -- 531 < 1 U 2420 -- 150 -- < 0.2 U 38000 -- 0.571 8 --- --- MW-6S 11/3/2015 -- < 1 U 7 -- 518 < 1 U 2470 19 170 -- < 0.2 U 35000 -- 0.441 7 --- --- r211D/2l-s 2-82 < 0.5 y $-} 240 }+ F 5000 y < 0-5 y E 5990 y -$ E 1000 y tel-} 8$33 j 2509 y 27600 8$-53 8.2 j �iw 6S 3fy2a=6 - < (i 14 - 64-2 < y 2-6$9 -24 339 - < 0.2 Y 4$988 - 9.3i2 MW -6S 3/28/2016 Beg < 0.5 U 7.9 36 < 5000 U < 0.5 U 2670 J 21.6 < 1000 U < 100 U < 0.1 U 44000 < 1000 U 0.34 7.1 J 1.62 0.5 MW -6S 6/28/2016 595 < 0.5 U 8.5 77 < 5000 U < 0.5 U 2380 J 19.5 < 1000 U < 100 U < 0.1 U 32000 -- 0.59 9 J --- 0.5 �iw 6S 7;'Ral6 - < y -7 - 5� tel-} 2368 3-4 2-29 - < 9.2 0 35000 - 9A46 2-9 �iw 6S 1=fV2-0=6 -I < 1y $ - 544 < 1 Y 2319 3S 4J99 - < 0.2 0 6$908 - ().898 42 MW -6S 12/8/2016 < 10 U < 0.5 U 7.2 370 < 5000 U < 0.5 U 2060 J 18.1 < 1000 U < 100 U < 0.1 U 44000 -- 1.1 8.6 J 0.0148 0.5 3ffW-1017 - -4--U 2 - 664 -4--U 2459 28 24-G - -<OTo I 3$909 - 4,7-S4 $ P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 2 of 6 TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 3 of 6 Analytical Parameter pH Turbidity Alkalinity Aluminum Antimony Arsenic Barium Beryllium B� carbonate Alkalinity Boron Cadmium Calcium Carbonate Alkalinity Chromium (VI) 1 Chromium Chloride Cobalt Copper Iron Lead Magnesium Manganese Mercury Reporting Units SU NTU ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L 15A NCAC 02L Standard 6.5-8.5 NE NE NE 1 10 700 4 NE 700 2 NE NE 30 30 250000 1 1000 300 1s NE 50 1 Sample ID Sample Collection Date Field Parameter Analytical Results MW -6S 3/23/2017 5.3 0.56 15500 < 100 U < 0.5 U < 0.1 U 47.1 0.0711 15500 < 50 U < 0.08 U 2520 < 5000 U 0.88 1.1 J+ 4600 3.5 0.8 43.5 J < 0.1 U 2900 36.8 < 0.2 U GWA-1S 6/22/2015 6.2 7.9 542003+ 220 < 0.5 U 0.12 J 34 < 0.2 U 54200 < 50 UJ < 0.08 U 9080 < 5000 U SAS 5.33+ 6800 0.453 0.61 J+ 300 0.0873 8680 15 0.086 J+ GWA-1S 9/24/2015 6.2 9.6 55800 5700 < 0.5 U 0.711+ 89 0.163 55800 < 50 U < 0.08 U 9950 < 5000 U 5.4 8200 7.7 8.1 7800 1.1 10400 160 < 0.2 U GWA-1S 4/4/2016 6.2 1.2 56500 58.23 < 0.5 U 0.17 21.6 < 0.1 U 56500 < 50 U < 0.08 U 8320 < 5000 U 9-.7 38 4000 0.043 0.243 59.4 < 0.1 U 7090 < 5 U < 0.2 U GWA-1S 9/22/2016 6.2 5.1 59400 176 < 0.5 U 0.15 33.7 0.013 59400 < 50 U < 0.08 U 8500 - S U 1.7 2.6 5700 0.13 < 0.5 U 234 < 0.1 U 7870 6.1 < 0.2 U GWA-1S 12/8/2016 6.2 6.36 59500 317 < 0.5 U 0.21 32 0.0381 59500 < 50 U < 0.08 U 9270 < 5000 U 2-.-6 3.4 5700 0.34 1.5 304 0.1 8200 9.8 < 0.2 U GWA-1S 3/21/2017 6.3 7.73 59400 246 < 0.5 U 0.22 27.6 0.0121 59400 < 50 U < 0.08 U 9100 < 5000 U -7-4 8.7 4700 0.34 1.43+ 339 0.0933 8220 8.5 0.0863+ MW -8S 11/2/2011 6.11 6.6 <1U <1U 21 <50U <1U <5U <5U 84 <1U 22 <0.05U MW -8S 7/3/2012 6.19 4.48 <1U <1U 23 <50U <1U <5U <5U 282 <1U 116 <0.05U MW -8S 11/7/2012 6.25 2.04 74000 < 1 U < 1 U 21 74000 < 50 U < 1 U 13100 < 5000 U < 5 U < 5 U 75 < 1 U 8050 38 < 0.05 U MW -8S 3/4/2015 5.96 7.71 < 1 < 1 30 < 50 < 1 20000 < 5 < 5 378 < 1 12600 130 < 0.05 MW -8S 7/6/2015 6.07 3.54 110000 155 < 1 U < 1 U 31 < 1 U 110000 < 50 U < 1 U 20100 < 5000 U < 5 U 3900 < 1 U < 5 U 198 < 1 U 12800 11 < 0.05 U MW -8S 7/5/2016 6.22 7.95 73700 441 < 1 U < 1 U 21 < 1 U 73700 < 50 U < 1 U 13700 < 5000 U < 5 U 3300 < 1 U < 5 U 592 < 1 U 7920 15 < 0.05 U MW -8S 9/29/2016 6.4 1.2 63100 238 < 0.5 U 0.0813 17.2 < 0.1 U 63100 < 50 U < 0.08 U 12700 -- .I 0.18 1.3 2700 0.13 0.153 347 < 0.1 U 7440 33.1 < 0.2 U rqw-8S X20 6.12 152 80500 42 <- 1 U <- 1 U 2-0 < 1 U 89509 <--58-U <- 1 U 14600 <-5888-U <- S U 3299 <- 1 U <- S U 70 < 1 U 8566 7 MW -8S 12/9/2016 6.6 0.6 67300 197 < 0.5 U 0.0663 17.2 0.0241 67300 < 50 U < 0.08 U 12400 < 5000 U 1.1 1.1 2700 0.16 0.433 259 < 0.1 U 6960 8 < 0.2 U Pqw-8S 3/6/29i7 6.11 2.97 312088 49 < 1 U <-1 U 34 < 1 U 312999 <--50-U <- 1 U 30209 <-5880-U - < 5 U 4190 <- 1 U <- 5-U 102 < 1 U 32609 3�2 MW -8S 3/20/2017 6.3 5.6 88800 609 < 0.5 U 0.0653 25.4 0.0233 88800 < 50 U < 0.08 U 14300 < 5000 U 1.3 1.9 3500 0.73 2.1 }840 < 0.1 U 9790 53.7 < 0.2 U Deep BG -2D 3/15/2016 8.44 0.54 69300 < 100 U 0.243 0.38 8.3 0.013 J+ 69300 < 50 U < 0.08 U 13400 < 5000 U 0.47 0.9 4900 0.0233 0.57 < 50 U < 0.1 U 3930 < 5 U < 0.2 U BG -2D 6/27/2016 8.3 4.3 61500 < 100 U < 0.5 U 0.37 9.2 0.013 61500 < 50 U < 0.08 U 15400 < 5000 U 0.28 2.8 4200 0.0513 0.483 54.8 < 0.1 U 5130 < 5 U < 0.2 U BG -2D 9/9/2016 7.7 1.1 69000 < 100 U < 0.5 U 0.33 10.4 < 0.1 U 69000 < 50 U < 0.08 U 13700 -- . I 0.32 0.373 3000 < 0.1 U 1.6 < 50 U < 0.1 U 5340 < 5 U < 0.2 U BG -2D 12/8/2016 7.7 2 70400 < 100 U < 0.5 U 0.44 10.8 0.0141 70400 < 50 U < 0.08 U 14000 < 5000 U 0.46 0.43 3000 0.0163 1.1 < 50 U < 0.1 U 5380 < 5 U < 0.2 U BG -2D 3/22/2017 7.9 0.3 71000 < 100 U 0.221 0.64 10.9 0.18 71000 < 50 U 0.15 13100 < 5000 U 0.3 1 J+ 29003+ 0.18 0.483 26.63 0.19 5300 2.5 3 < 0.2 U MW -8D 11/2/2011 6.3 6.2 <1U <1U 17 <50U <1U <5U <5U 88 <1U 7 <0.05U MW -8D 3/7/2012 6.52 3.55 <1U <1U 16 <50U <1U <5U <5U 129 <1U 6 <0.05U MW -8D 7/3/2012 6.36 4.48 <1U <1U 17 <50U <1U <5U <5U 64 <1U <5U <0.05U MW -8D 11/7/2012 6.33 2.59 55000 < 1 U < 1 U 17 55000 < 50 U < 1 U 10400 < 5000 U < 5 U < 5 U 111 < 1 U 5120 < 5 U < 0.05 U MW -8D 3/6/2013 6.17 4.77 50000 < 1 U < 1 U 16 < 50 U < 1 U 10100 < 5 U < 5 U 157 < 1 U 4830 < 5 U < 0.05 U MW -8D 7/8/2013 6.21 3.87 51000 < 1 U < 1 U 18 < 50 U < 1 U 10900 < 5 U < 5 U 307 < 1 U 5190 5 < 0.05 U MW -8D 11/4/2013 6.32 4.78 46000 < 1 U < 1 U 17 < 50 U < 1 U 10300 < 5 U < 5 U 224 < 1 U 4990 < 5 U < 0.05 U MW -8D 3/3/2014 6.19 8.03 49000 < 1 U < 1 U 19 < 50 U < 1 U 11100 < 5 U < 5 U 432 < 1 U 5310 6 < 0.05 U MW -8D 11/3/2014 6.38 4.78 47000 < 1 U < 1 U 17 < 50 U < 1 U 10700 < 5 U < 5 U 214 < 1 U 5140 < 5 U < 0.05 U MW -8D 3/4/2015 6.25 4.91 < 1 < 1 18 < 50 < 1 10700 < 5 < 5 123 < 1 5190 < 5 < 0.05 MW -8D 7/6/2015 6.32 5.48 44400 404 < 1 U < 1 U 20 < 1 U 44400 < 50 U < 1 U 11100 < 5000 U < 5 U 3300 < 1 U < 5 U 464 < 1 U 5650 7 < 0.05 U MW -8D 11/3/2015 6.34 6.96 49400 401 1.01 < 1 U 18 < 1 U 49400 < 50 U < 1 U 11000 B2 < 5000 U < 5 U 3400 < 1 U < 5 U 443 < 1 U 5420 6 < 0.05 U MW -8D 3/2/2016 6.33 4.74 48600 216 2.44 < 1 U 17 < 1 U 48600 < 50 U < 1 U 10600 < 5000 U < 5 U 3400 B2 < 1 U < 5 U 279 < 1 U 5220 < 5 U MW -8D 7/5/2016 6.24 2.06 53600 109 < 1 U < 1 U 17 < 1 U 53600 < 50 U < 1 U 10800 < 5000 U < 5 U 3700 < 1 U < 5 U 124 < 1 U 5160 < 5 U < 0.05 U MW -8D 9/29/2016 5.9 2.2 52400 151 < 0.5 U 0.0433 17.7 < 0.1 U 52400 < 50 U < 0.08 U 12100 < 5 U 0.4 0.82 3200 0.22 0.223 198 < 0.1 U 5880 3.63 < 0.2 U rww-se e 6.24 1.65 53809 S7 <- 1 U <-1 U 17 < 1 U 63999 <-59-U <- 1 U 10$99 < 5800 U - <- 5 U 3399 <- 1 U <-5-U 70 < 1 U 5270 < 5 U naw -se 3/6/20i7 6.41 2.28 53699 27 <- 1 U <-1 U 18 < 1 U 53600 < SO U <- 1 U 11409 < 5000 U - <- 5 U 3398 <- 1 U < S 35 < 1 U 5450 < 5 U MW -81) 3/20/2017 6.5 0.3 54700 < 100 U < 0.5 U 0.0733 17 0.0461 54700 < 50 U < 0.08 U 10800 < 5000 U 0.5 J+ 1.7 3200 0.0653 0.15)+ < 50 U < 0.1 U 5230 < 5 U 2.4 3 Bedrock BG-3BRU 9/23/2015 6.9 5.1 40400 < 100 U 0.93 0.6 12 < 0.2 U 40400 < 50 U < 0.08 U 8400 < 5000 U 1.13+ 2200 0.21) 4.6 93 0.16 2810 5.9 < 0.2 U BG 3BRU 15 7-.3 5-.7 49700 < 100 U 8 5i 1.6 8-.13 < 0.2 U 49799 <--58-U < 9:98-U 11109 < 5000 U 9.2 1:4 2498 9.48 J 611 110 0.21 3950 12 < 0.2 Ul BG-3BRU 12/10/2015 7.7 1.3 40400 < 100 U 0.71 0.62 8.8 < 0.2 U 40400 < 50 U < 0.08 U 8850 < 5000 U 0.2 1.3 2100 < 0.5 U 2.6 53 0.051) 2520 3.8 J < 0.2 U BG -3 RU 3/15/2016 7.5 2.8 56500 < 100 U 0.76 0.78 6.3 < 0.1 U 56500 < 50 U < 0.08 U 11100 < 5000 U 0.18 0.863+ 1700 0.0863 1.2 42.83+ < 0.1 U 2820 9.3 < 0.2 U BG-3BRU 6/24/2016 7.5 1.9 47200 < 100 U 0.63 2.4 9 < 0.1 U 47200 < 50 U < 0.08 U 11800 < 5000 U 0.025 J 0.31 J 2200 0.1 3.7 264 < 0.1 U 3050 32=8 < 0.2 U BG-3BRU 9/9/2016 7 1.3 44300 < 100 U 0.66 0.81 9.7 < 0.1 U 44300 < 50U < 0.08 U 8960 <-s U < 0.03 U 0.54 1500 0.0873 2.1 66 < 0.1 U 2650 18� < 0.2 U P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 3 of 6 TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 4 of 6 Analytical Parameter Methane Molybdenum Nickel Nitrate + Potassium Selenium Sodium Strontium Sulfate Sulfide Thallium Total Dissolved Solids Total Organic Carbon Vanadium Zinc Radium (Total) UraniumNitrite (Total) Reporting Units ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L pCi/L ug/L 15A NCAC 02L Standard NE NE 100 NE NE 20 NE NE 250000 NE 0.2 500000 NE 0.3 1000 NE NE Sample ID Sample Collection Date Analytical Results MW -6S 3/23/2017 < 10 U < 0.5 U 7.2 510 < 5000 U < 0.5 U 24201 21.2 < 1000 U < 100 U < 0.1 U 48000 0.9 7.73 0.501 0.5 GWA-1S 6/22/2015 2.91+ 0.143 7.6 260 < 5000 U < 0.5 U 10200 55 9300 < 100 U 0.021 J 116000 1100 2.63+ < 10 UJ --- --- GWA-1S 9/24/2015 1.41+ < 0.5 U +s.5 73 < 5000 U 0.243 8110 58 4300 -- < 0.1 U 11600023500 10 14 --- --- GWA-1S 4/4/2016 1.61+ 0.163 2.9 560 < 5000 U < 0.5 U 6790 43 2100 < 100 U < 0.1 U 114000 < 1000 U 4.6 < 10 U --- --- GWA-1S 9/22/2016 < 10 U 0.143 5.6 240 < 5000 U < 0.5 U 7800 59.4 5400 < 0.1 U 105000 < 1 U 3.7 < 10 U --- --- GWA-1S 12/8/2016 < 10 U 0.263 5.7 260 < 5000 U < 0.5 U 7220 58.4 4400 < 100 U 0.0153 72000 4.4 2.83 --- GWA-1S 3/21/2017 < 10 U 0.211 4.5 400 < 5000 U < 0.5 U 7670 53.9 3000 < 100 U < 0.1 U 116000 4.7 < 10 U --- --- MW-8S 11/2/2011 -- -- < 5 U -- -- < 1 U -- -- 3200 -- -- 150000 -- < 5 U --- --- MW-8S 7/3/2012 < 5 U -- < 1 U -- 3000 < 250000 U < 5 U --- --- MW-8S 11/7/2012 < 5 U 972 < 1 U 8160 2700 -- 140000 < 5 U --- --- MW-8S 3/4/2015 -- < 5 1060 < 1 9320 7500 < 0.2 170000 -- < 5 --- --- MW-8S 7/6/2015 < 1 U < 5 U 1010 < 1 U 9480 -- 4100 < 0.2 U 170000 4.91 < 5 U --- --- MW-8S 7/5/2016 -- < 1 U < 5 U -- 1050 < 1 U 8220 127 2200 < 0.2 U 120000 7.69 < 5 U --- --- MW-8S 9/29/2016 17.2 0.363 0.82 160e < 5000 U < 0.5 U 8300 108 2000 0.1 < 0.1 U 155000 < 1 U 7.9 < 10 U --- 0.5 Piw 8S 44,11/201-6 - < U <--S U - 3060 <- 1 U 8360 3-2 2590 - X0.2 U 379889 6.21 < 5 U - - MW -8S 12/9/2016 < 10 U 0.423 0.85 1s0e < 5000 U 0.343 7170 112 1500 < 100 U < 0.1 U 101000 7.1 < 10 U -0.15 0.5 Piw 8S 0/6%2017 - F1 U <--5-U - 1040 <- 1 U 9490 3799 6400 - X0.2 U 360000 4.73 < S U - - MW -8S 3/20/2017 < 10 U 0.23+ 3.2 1200 < 5000 U < 0.5 U 7790 127 3300 < 100 U < 0.1 U 133000 -- 8.1 18.73+ 0.401 0.5 Deep BG -2D 3/15/2016 2A 3 s 4 < 0.5 U 1100 8130 < 0.5 U 16500 117 13000 < 100 U < 0.1 U 116000 < 1000 U 6.6 53+ 0.244 0.28 3 BG -2D 6/27/2016 < 10 U 5:6 1.6 1300 6050 < 0.5 U 13000 128 10100 < 100 U < 0.1 U 85000 -- 8.2 < 10 U 0.609 0.49 3 BG -2D 9/9/2016 < 10 U 2 < 0.5 U 1400 6890 < 0.5 U 11600 127 6300 < 0.1 U < 0.1 U 113000 < 1 U 6.5 7.13 --- 0.36 J BG -2D 12/8/2016 < 10 U 1.4 < 0.5 U 1500 6870 < 0.5 U 10400 127 6700 < 100 U < 0.1 U 89000 6.3 < 10 U 0.1973 0.383 BG -2D 3/22/2017 < 10 U 1.5 0.61 1500 6030 0.363 11800 129 6600 < 100 U 0.16 119000 6.8 < 10 U 0.436 0.4 3 MW -8D 11/2/2011 __ -- < 5 U -- -- < 1 U -- -- 2400 -- -- 130000 -- < 5 U --- --- MW-8D 3/7/2012 < 5 U < 1 U 2400 123000 < 5 U --- --- MW-8D 7/3/2012 < 5 U -- < 1 U -- 2100 < 2500001/ < 5 U --- --- MW-8D 11/7/2012 < 5 U 1420 < 1 U 7240 2000 120000 < 5 U --- --- MW-8D 3/6/2013 < 5 U 1350 < 1 U 6720 2100 120000 < 5 U --- --- MW-8D 7/8/2013 < 5 U 1450 < 1 U 7370 2100 130000 < 5 U --- --- MW-8D 11/4/2013 < 5 U 1340 < 1 U 6980 1800 120000 < 5 U --- --- MW-8D 3/3/2014 < 5 U 1460 < 1 U 73802100 110000 < 5 U --- --- MW -8D 11/3/2014 < 5 U 1350 < 1 U 7020 2000 -- 110000 < 5 U --- --- MW -8D 3/4/2015 -_ < 5 1390 < 1 7280 1900 < 0.2 110000 < 5 --- --- MW -8D 7/6/2015 < 1 U < 5 U 1440 < 1 U 7380 -- 1800 < 0.2 U 120000 6.23 < 5 U --- --- MW -8D 11/3/2015 < 1 U < 5 U 1380 < 1 U 7230 110 1900 < 0.2 U 100000 6.12 < 5 U --- --- MW -8D 3/2/2016 < 1 U < 5 U 1340 < 1 U 7000 108 2100 < 0.2 U 120000 6.51 < 5 U MW -8D 7/5/2016 < 1 U < 5 U -- 1360 < 1 U 7130 108 2000 < 0.2 U 110000 5.63 < 5 U MW -8D 9/29/2016 < 10 U 0.493 1.3 2300 < 5000 U < 0.5 U 7960 112 1800 < 0.1 U < 0.1 U 95000 < 1 U 6 < 10 U --- 0.5 Piw 8D =1/=/20=6 <1 U <- 5 U - 3348 <- 1 U 7970 308 3809 <0.2 U 349888 S.57 <--S U Piw 81) 3/6/28== - <1 U < 5 U - 3398 <- 1 U 7440 333 3098 - < 0.2 U 339898 S.59 <--5-11 MW -8D 3/20/2017 < 10 U 0.453+ 1.8 2300 < 5000 U < 0.5 U 7240 110 1500 < 100 U 0.0423 89000 5.5 4.23+ 0.572 0.5 Bedrock BG-3BRU 9/23/2015 1.81+ 5.4 0.97 240 5210 0.343 7630 56 9380 < 100 U < 0.1 U 96000 1600 12.9 19 --- --- BG .3BRU 1840 15 -33}+ 6.-3 3-.6 270 6439 8.31 3 39699 72 33999 r 100 i i cy i i 13 nen n en 3 9� 31 - - BG-3BRU 12/10/2015 1.41+ 5.1 1.4 440 46103 0.263 7460 54 8600 < 100 U < 0.1 U 56000 6203 10 19 --- --- BG-3BRU 3/15/2016 2.41+ 5.5 0.58 280 45003 0.323 9800 60.9 12700 < 100 U < 0.1 U 82000 10500 8.6 14.23+ 0.08222 0.0789 BG-3BRU 6/24/2016 < 10 U 5.9 0.55 360 5320 < 0.5 U 11700 71.1 1-17-00 < 100 U < 0.1 U 107000 -- 6.9 5.7 J 0.948 GA 3 BG-3BRU 9/9/2016 < 10 U 4.7 1.3 < 0.02 U 5950 0.383 8640 58.6 1190e < 0.1 U 1 84000 15703 1 9.3 1 10.4 1 -- 0.5 P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 4 of 6 TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC Prepared by: LWD Checked by: PBW Notes: 54 - Indicates value omitted from dataset. Indicates parameter not measured or analyzed. Indicates data removed /identified as an outlier. Indicates data removed due to autocorrelation. mg - N/L - Milligrams nitrogen per liter pCi/L - picocuries per liter mg/L - Milligrams per liter S.U. - Standard Unit NE - Not established ug/L - Micrograms per liter NTU - Nephelometric turbidity unit ug/mL - micrograms per milliliter < - concentration not detected at or above the reporting limit. * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April, 1, 2013. Hexavalent chromium does not have a NC 2L/IMAC standard; therefore, the NC 2L standard for total chromium is relied upon as a surrogate. B1 - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample was greater than SOX the concentration in the method blank. Analyte concentration in sample is not affected by blank contamination. 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. B5 - Target analyte was present in blank(s) above the method detection limit but less than the reporting limit. Data is valid for compliance purposes. HS - Results are from sample aliquot taken from VOA vial with headspace (air bubble greater than 6 mm diameter). P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 5 of 6 Analytical Parameter pH Turbidity Alkalinity Aluminum Antimony Arsenic Barium Beryllium B� carbonate Alkalinity Boron Cadmium Calcium Carbonate Alkalinity Chromium 1 (VI) Chromium Chloride Cobalt Copper Iron Lead Magnesium Manganese Mercury Reporting Units SU NTU ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L 15A NCAC 02L Standard 6.5-8.5 NE NE NE 1 10 700 4 NE 700 2 NE NE 30 30 250000 1 1000 300 1s NE 50 1 Sample ID Sample Collection Date Field Parameter Analytical Results BG-3BRU 12/7/2016 7.1 0.45 42400 < 100 U 0.29 J 0.63 10.3 < 0.1 U 42400 < 50 U < 0.08 U 8790 1 < 5000 U 1.2 0.87 1400 0.092 J 1.3 75.8 < 0.1 U 2440 2.3-3 < 0.2 U BG-3BRU 3/21/2017 7 0.1 42300 < 100 U 0.2 J 0.53 10.1 < 0.1 U 42300 < 50 U < 0.08 U 8200 < 5000 U 0.048 0.6 1300 0.25 0.81 J+ 137 < 0.1 U 2470 45-.6 0.099 J+ MW -6D 3/7/2011 6.98 2 -- -- < 1 U < 1 U 63 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 31 < 1 U -- < 5 U < 0.05 U MW -6D 7/5/2011 6.63 0.9 -- -- <1U <1U 64 -- -- <50U <1U -- -- -- <5U -- -- <5U <10U <1U -- <5U <0.05U MW -6D 11/2/2011 6.83 0.5 -- -- <1U <1U 62 -- -- <50U <1U -- -- -- <5U -- -- <5U <10U <1U -- <5U <0.05U MW -6D 3/7/2012 6.8 0.94 -- -- < 1 U < 1 U 65 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 26 < 1 U -- < 5 U < 0.05 U MW -6D 7/3/2012 5.83 0.5 -- -- < 1 U < 1 U 70 -- -- < 50 U < 1 U -- -- -- < 5 U -- -- < 5 U 18 < 1 U -- < 5 U < 0.05 U MW -6D 11/7/2012 6.69 0.54 72000 -- < 1 U < 1 U 70 -- 72000 < 50 U < 1 U 11200 < 5000 U -- < 5 U -- -- < 5 U 25 < 1 U 6530 < 5 U < 0.05 U MW -6D 3/6/2013 6.58 2.86 65000 -- < 1 U < 1 U 73 -- -- < 50 U < 1 U 11300 -- -- < 5 U -- -- < 5 U 62 < 1 U 6510 < 5 U < 0.05 U MW -6D 7/8/2013 6.55 1.98 69000 -- < 1 U < 1 U 84 -- -- < 50 U < 1 U 12500 -- -- < 5 U -- -- < 5 U 127 < 1 U 7130 < 5 U < 0.05 U MW -6D 11/4/2013 6.6 2.82 66000 -- < 1 U < 1 U 81 -- -- < 50 U < 1 U 12400 -- -- < 5 U -- -- < 5 U 55 < 1 U 7140 < 5 U < 0.05 U MW -6D 3/3/2014 6.58 1.35 69000 -- < 1 U < 1 U 83 -- -- < 50 U < 1 U 13000 -- -- < 5 U -- -- < 5 U 47 < 1 U 7280 < 5 U < 0.05 U MW -6D 7/1/2014 6.69 2.35 61000 -- < 1 U < 1 U 86 -- -- < 50 U < 1 U 12700 -- -- < 5 U -- -- < 5 U 78 < 1 U 7210 < 5 U < 0.05 U MW -6D 11/3/2014 6.67 1.24 68000 -- < 1 U < 1 U 76 -- -- < 50 U < 1 U 11800 -- -- < 5 U -- -- < 5 U 25 < 1 U 6750 < 5 U < 0.05 U MW -6D 3/4/2015 6.69 1.66 -- -- < 1 < 1 77 -- -- < 50 < 1 12000 -- -- < 5 -- -- < 5 33 < 1 6820 < 5 < 0.05 MW -6D 7/1/2015 6.73 7.97 64700 240 0.21 J < 0.5 U 86 < 0.2 U 64700 < 50 U < 0.08 U 12600 < 5000 U -- 1.5 J 4700 < 0.5 U 0.52 J 110 0.055 J 7370 3.1 J < 0.2 U MW 61) ;io,=20== 6,74 7.3i 63190 3$3 < 1 y < 1 IJ 86 <1y 63100 E SO Y < 1 Y -1-2 6 9 G X5000 Y -< 5 y 3909 1 Y < 5 Y 486 < 1 U 744a MW 6e ==f ;20 5 6-.-8 3:48 65889 46 < 1 y < 1 Ii 74 < 1 y 65889 < 50 y < 1 Y , 22moi F5880 Y - E 5 if 3699 1 if <3 y 44 < 1 y 6979 < 5 y MW -6D 12/10/2015 6.8 2.4 69100 69 J < 0.5 U < 0.5 U 87 < 0.2 U 69100 < 50 U < 0.08 U 13300 < 5000 U 0.47 0.78 3200 0.13 J 3.9 J+ 140 0.07 J 7280 5.1 < 0.2 U MW 61) 3fIR44a 0-59 9.92 66999 394 2-4-5 Ali 9� < 1 y 66996 < 50 l3 < 1 y i2990 F5909 y - < 5 y 368 -E 1 y <3 y _553 < 1 y 7619 36 - MW -6D 3/28/2016 6.2 1.6 43600 < 100 U 0.7 0.078 J 50.3 < 0.1 U 43600 < 50 U < 0.08 U 8160 < 5000 U 0.15 0.29 J+ 2200 0.03 J+ 2.8 < 50 U 0.14 4500 < 5 U < 0.2 U MW -6D 6/28/2016 6.1 0.9 38300 < 100 U < 0.5 U 0.044 J 96.1 < 0.1 U 38300 < 50 U < 0.08 U 13200 < 5000 U 0.69 0.98 1800 0.07 J 1 89.3 < 0.1 U 7720 5.4 < 0.2 U MW 69 f5f20=6 6, KL X44 70599 �5 < 1 y 1i 88 < 1 y 70686 < 50 l3 < 1 y 33499 F5009 y - < S y 3499 -E 1 Y S Y 49 < 1 Y 6839 MW -6D 9/26/2016 6.9 3.3 65100 169 < 0.5 U 0.068 J 103 < 0.1 U 65100 < 50 U < 0.08 U 12200 FS -U 0.82 1.2 2800 0.16 1.1 287 < 0.1 U 6970 7 < 0.2 U MW 6e IV4f244-6 6-42 3.42 69700 2-9 < 1 l3 1i -74 < 1 y 69700 < 50 l3 < 1 y 33266 F5909 y - < 5 y 3368 < <31y 33 < 1 y 6999 MW -6D 12/8/2016 7 0.31 70700 < 100 U < 0.5 U 0.086 J 90.8 0.031 J 70700 < 50 U < 0.08 U 13100 < 5000 U 0.43 0.61 2900 0.021 J 0.27 J < 50 U < 0.1 U 7400 < 5 U < 0.2 U MW 69 3f&f2417 6-78 2-.-6 65509 34 < 1 y < 1 IJ 83 < 1 y 68586 < SO l3 1Y 12790 F59 9 Y - < S y 368 < 1 IJ <3 y 64 < 1 y 7029 < 5 y MW -6D 3/23/2017 6.9 0.34 70400 < 100 U < 0.5 U 0.046 J 87.7 < 0.1 U 70400 < 50 U < 0.08 U 13200 < 5000 U 0.4 J+ 0.81 J+ 2900 0.018 J 0.54 < 50 U < 0.1 U 7590 < 5 U < 0.2 U MW-6BR 6/27/2016 &.4 8.5 76900 316 1.2 1.7 28 0.052 J 76900 < 50 U < 0.08 U 13400 < 5000 U < 0.03 U 5.1 3600 L0.18 1.8 393 0.5 4160 97.7 < 0.2 U Prepared by: LWD Checked by: PBW Notes: 54 - Indicates value omitted from dataset. Indicates parameter not measured or analyzed. Indicates data removed /identified as an outlier. Indicates data removed due to autocorrelation. mg - N/L - Milligrams nitrogen per liter pCi/L - picocuries per liter mg/L - Milligrams per liter S.U. - Standard Unit NE - Not established ug/L - Micrograms per liter NTU - Nephelometric turbidity unit ug/mL - micrograms per milliliter < - concentration not detected at or above the reporting limit. * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April, 1, 2013. Hexavalent chromium does not have a NC 2L/IMAC standard; therefore, the NC 2L standard for total chromium is relied upon as a surrogate. B1 - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample was greater than SOX the concentration in the method blank. Analyte concentration in sample is not affected by blank contamination. 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. B5 - Target analyte was present in blank(s) above the method detection limit but less than the reporting limit. Data is valid for compliance purposes. HS - Results are from sample aliquot taken from VOA vial with headspace (air bubble greater than 6 mm diameter). P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 5 of 6 TABLE 1 BACKGROUND GROUNDWATER RESULTS THROUGH MARCH 2017 BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC Prepared by: LWD Checked by: PBW Notes: 54 - Indicates value omitted from dataset. Indicates parameter not measured or analyzed. Indicates data removed /identified as an outlier. Indicates data removed due to autocorrelation. mg - N/L - Milligrams nitrogen per liter pCi/L - picocuries per liter mg/L - Milligrams per liter S.U. - Standard Unit NE - Not established ug/L - Micrograms per liter NTU - Nephelometric turbidity unit ug/mL - micrograms per milliliter < - concentration not detected at or above the reporting limit. * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April, 1, 2013. Hexavalent chromium does not have a NC 2L/IMAC standard; therefore, the NC 2L standard for total chromium is relied upon as a surrogate. B1 - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample was greater than SOX the concentration in the method blank. Analyte concentration in sample is not affected by blank contamination. 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. B5 - Target analyte was present in blank(s) above the method detection limit but less than the reporting limit. Data is valid for compliance purposes. HS - Results are from sample aliquot taken from VOA vial with headspace (air bubble greater than 6 mm diameter). P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 6 of 6 Analytical Parameter Methane Molybdenum Nickel Nitrate + Potassium Selenium Sodium Strontium Sulfate Sulfide Thallium Total Dissolved Solids Total Organic Carbon Vanadium Zinc Radium (Total) UraniumNitrite (Total) Reporting Units ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L pCi/L ug/L 15A NCAC 02L Standard NE NE 100 NE NE 20 NE NE 250000 NE 0.2 500000 NE 0.3 1000 NE NE Sample ID Sample Collection Date Analytical Results BG-3BRU 12/7/2016 < 10 U 4 1.5 29 4380J < 0.5 U 7390 54.8 9SB9 < 100 U < 0.1 U 79000 -- 10.1 4.6 J 0.939 0.5 BG-3BRU 3/21/2017 < 10 U 3.8 2.1 170 3880 J < 0.5 U 8040 53.8 8290 < 100 U < 0.1 U 87000 -- 4.8 < 10 U 0.465 0.5 MW -6D 3/7/2011 -- -- < 5 U -- -- < 1 U -- -- 1300 -- -- 100000 -- -- < 5 U --- --- MW-6D 7/5/2011 -- -- < 5 U -- -- < 1 U -- -- 1400 -- -- 97000 -- -- < 5 U --- --- MW-6D 11/2/2011 -- -- < 5 U -- -- < 1 U -- -- 1200 -- -- 93000 -- -- < 5 U --- --- MW-6D 3/7/2012 -- -- < 5 U -- -- < 1 U -- -- 1300 -- -- 106000 -- -- < 5 U --- --- MW -6D 7/3/2012 -- -- < 5 U -- -- < 1 U -- -- 1500 -- -- X250000 -U -- -- < 5 U --- --- MW-6D 11/7/2012 -- -- < 5 U -- 2100 < 1 U 5860 -- 1400 -- -- 110000 -- -- < 5 U --- --- MW-6D 3/6/2013 -- -- < 5 U -- 2150 < 1 U 5630 -- 1400 -- -- 120000 -- -- < 5 U --- --- MW-6D 7/8/2013 -- -- < 5 U -- 2370 < 1 U 6210 -- 1600 -- -- 140000 -- -- < 5 U --- --- MW-6D 11/4/2013 -- -- < 5 U -- 2310 < 1 U 6080 -- 1500 -- -- 120000 -- -- < 5 U --- --- MW-6D 3/3/2014 -- -- < 5 U -- 2360 < 1 U 6240 -- 170 -- -- 120000 -- -- 7 --- --- MW-6D 7/1/2014 -- -- < 5 U -- 2500 < 1 U 6140 -- 1800 -- -- 110000 -- -- < 5 U --- --- MW-6D 11/3/2014 -- -- < 5 U -- 2170 < 1 U 5840 -- 1700 -- -- 110000 -- -- < 5 U --- --- MW-6D 3/4/2015 -- -- < 5 -- 2230 < 1 6000 -- 1700 -- < 0.2 120000 -- -- < 5 --- --- MW-6D 7/1/2015 1.2 J+ 0.27 J < 0.5 U 500 2640 J < 0.5 U 6360 96 2400 < 100 U < 0.1 U 111000 < 1000 U 8.8 < 10 U --- --- MW-SD _ _-- - 1 y < 5-y - 241 i9 Ell:} 6-88 - 3789 - x-^0.2 Y 120000 - 3i.4 MW 6D 1 /3/_els - 1 (i <5 Lf - 2iS6 < 1 (i 6848 1-46 389 - < 0.2 Y i$8989 - 938 < 5 Lf MW -6D 12/10/2015 4.7 J+ 0.37 J 0.3 J+ 380 J+ 3070J < 0.5 U 6900 92 2200 < 100 U < 0.1 U 71000 < 1000 U 8.7 < 10 U --- --- MW-6D 3;b/2410 + E§-() - 27i9 < 1 y 6980 3$1- 2999 <-0To 11� 9.93 < 5y MW -6D 3/28/2016 1.6 J+ 1.1 2.2 360 3050 J < 0.5 U 5460 58.2 2400 < 100 U < 0.1 U 93000 10500 11.7 17.4 1.559 0.5 MW -6D 6/28/2016 < 10 U 0.41 0.64 790 3330J < 0.5 U 6410 98.5 2300 < 100 U < 0.1 U 68000 -- 8 < 10 U --- 0.5 MW 6D Flo - < 1 y < 5 (f - 2299 < 1 y 5990 96 3389 - < 0.2 0 310809 - 914 Irl+ MW -6D 9/26/2016 < 10 U 0.29 J < 0.5 U 530 < 5000 U < 0.5 U 5960 96.7 1700 0.1 U < 0.1 U 115000 < 1 U 9.6 2.6 J --- 0.5 MW 6D W/2416 - 'E 1 y < 5 (f - 2349 < 1 y 5949 94 J-899 - moo 130899 - 948 tel+ MW -6D 12/8/2016 < 10 U 0.37 J < 0.5 U 440 3120 J < 0.5 U 5540 99.4 2200 < 100 U < 0.1 U 113000 -- 7.6 < 10 U 1.117 0.5 MW 6D > 7 - tel} 5Y - 2399 < 1 li 6110 94 3389 - < 0To 320809 - 935 tel+ MW -6D 3/23/2017 < 10 U 0.38 J < 0.5 U 440 2990J < 0.5 U 6280 96.6 1800 < 100 U < 0.1 U 111000 -- 8.4 < 10 U 0.172 0.5 MW-6BR 6/27/2016 < 10 U 10.4 2.7 < 20 U 2980J < 0.5 U 212DA 78.7 3900 < 100 U < 0.1 U 120000 -- -1 15.4 --- 0.483 Prepared by: LWD Checked by: PBW Notes: 54 - Indicates value omitted from dataset. Indicates parameter not measured or analyzed. Indicates data removed /identified as an outlier. Indicates data removed due to autocorrelation. mg - N/L - Milligrams nitrogen per liter pCi/L - picocuries per liter mg/L - Milligrams per liter S.U. - Standard Unit NE - Not established ug/L - Micrograms per liter NTU - Nephelometric turbidity unit ug/mL - micrograms per milliliter < - concentration not detected at or above the reporting limit. * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April, 1, 2013. Hexavalent chromium does not have a NC 2L/IMAC standard; therefore, the NC 2L standard for total chromium is relied upon as a surrogate. B1 - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample was greater than SOX the concentration in the method blank. Analyte concentration in sample is not affected by blank contamination. 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. B5 - Target analyte was present in blank(s) above the method detection limit but less than the reporting limit. Data is valid for compliance purposes. HS - Results are from sample aliquot taken from VOA vial with headspace (air bubble greater than 6 mm diameter). P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 1 - Buck BG GW Values.xlsx Page 6 of 6 TABLE 2 GROUNDWATER BACKGROUND THRESHOLD VALUES BUCK STEAM STATION DUKE ENERGY CAROLINAS, LLC, SALISBURY, NC Parameter Reporting Unit NCAC 02L Standard Shallow Background Threshold Values Deep Bedrock PH* S.U. 6.5-8.5 4.5 - 6.4 5.9 -8.4 5.8 - 7.8 Alkalinity mg/L NE 67 70 72 Aluminum ug/L NE 273 404 240 Antimony ug/L 1° 1 1 1 Arsenic ug/L 10 1 1 1 Barium Ng/L 700 44 19 91 Beryllium ug/L 4° 0.1 1 0.2 Bicarbonate mg/L NE 92 84 72 Boron ug/L 700 50 50 50 Cadmium Ng/L 2 1 1 1 Calcium mg/L NE 13 14 13 Carbonate mg/L NE 5 5 5 Chloride mg/L 250 8 4 5 Chromium (VI) 1 Ng/L 10 2.4 0.5t 1.3 Chromium pg/L 10 5 5 4 Cobalt ug/L 1° 8 0.3 0.3 Copper Ng/L 1000 4 5 5 Iron Ng/L 300 647 500 147 Lead Ng/L 15 1 1 1 Magnesium mg/L NE 9 6 8 Manganese Ng/L 50 198 7 7 Mercury Ng/L 1 0.05 0.05 0.05 Methane Ng/L NE 10 lot 10 Molybdenum ug/L NE 1 2t 5.9 Nickel pg/L 100 7 5 5 Nitrate + Nitrite mg-N/L NE 0.4 2t 0.9 Potassium mg/L NE 5 7 7 Selenium pg/L 20 1 1 1 Sodium mg/L NE 8 13 9.8 Strontium ug/L NE 108 129 98.5 Sulfate mg/L 250 3 7 2 Sulfide mg/L NE 0.1 0.1t 0.1 TDS mg/L 500 212 130 145 Thallium Ng/L 0.2° 0.2 0.2 0.2 TOC mg/L NE 1100 It 16001 Vanadium ug/L 0.3° 7.69 8.42 14.1 Zinc Ng/L 1000 26 10 17 Radium (Total) pCi/L NE 1.6 0.6t 1.6t Uranium (Total) pg/mL NE 0.0005 0.00051 0.00051 Prepared by: LWD Checked by: TME Notes: * - Upper and lower tolerance limits calculated for parameter A - Interim Maximum Allowable Concentrations (IMACs) of 15A NCAC .021- Standard, Appendix 1, April 1, 2013 pg/L - micrograms per liter pg/mL - micrograms per milliliter t - Provisional; dataset contains less than 10 valid samples ' - Hexavalent chromium does not have a NC 2L/IMAC standard; therefore, the NC 2L standard for total chromium is relied upon as a surrogate. mg/L - milligrams per liter NE - Not Established pCi/L - picocuries per liter Radium (Total) - Radium -226 and Radium -228 combined S.U. - Standard Unit TDS - Total Dissolved Solids P:\Duke Energy Carolinas\Statistics_CAMA\Background Determinations for NCDEQ July 7 2017\BTV TECH MEMO\Buck\Groundwater\Tables\TABLE 2 - Buck BG GW BTVs Page 1 of 1