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HomeMy WebLinkAbout8003_Rowan_CDLF_AssessmentWorkPlanAddendum_FID1756477_20221222XXtil) GOLDER December 21, 2022 Jaclynne Drummond, Hydrogeologist Department of Environmental Quality Division of Waste Management Solid Waste Section 2090 US Highway 70 Swannanoa, North Carolina 28778 jaclynne.drummond@ncdenr.gov ASSESSMENT MONITORING WORK PLAN ADDEMDUM ROWAN COUNTY CLOSED C&D LANDFILL, PERMIT NO. 80-03 ROWAN COUNTY, NORTH CAROLINA Dear Jackie, Project No. 21456818.200 On behalf of Rowan County, WSP USA Inc. (WSP), is submitting this Assessment Monitoring Work Plan (AMWP) Addendum for the Rowan County Closed Construction & Demolition (C&D) Landfill. This AMWP Addendum was prepared in response to recent detections of benzene at concentrations above the NC 2L Standard in samples from groundwater monitoring well MW-19R. A summary of historical NC Appendix I volatile organic constituent (VOC) detections at groundwater monitoring wells is attached as Table 1. Monitoring well MW-18R2 is currently in assessment monitoring per the approved AMWP submitted on January 18, 2022, and approved on January 20, 2022. Based on the analytical results from the second semi-annual water quality monitoring event of 2022, Rowan County will initiate the Assessment Monitoring Program at the Rowan County Closed C&D Landfill for MW-19R. Additional assessment activities will also continue at MW-18R2 as described below. It is Rowan County's intent to comply with the requirements of 15A NCAC 13B. 0545.(a) and (b). 15A NCAC 13B .0545(a)(1) and (b)(1): INSTALLATION OF ADDITIONAL MONITORING POINT: Due to the close proximity of well MW-19R to the unnamed tributary of Second Creek and the infeasibility of accessing downgradient locations with a drill rig, Rowan County proposes to obtain groundwater data through pore water sampling from below the tributary streambed downgradient of MW-19R during the next semi-annual groundwater monitoring event, in lieu of installing additional assessment monitoring wells. The location for collection of the proposed pore water sample (PWS-2) is shown on Figure 1. The samples will be collected with an AMS Retract -A -Tip Sampler and a peristaltic pump or similar equipment. The sampler will be decontaminated prior to collecting the sample and new tubing will be used. The sampler will be hammered into the subsurface along the stream bottom to a depth ranging from approximately 0.5 to 1.0 feet below ground surface. The rods of the sampler will be retracted approximately one inch to expose a screen at the bottom of the sampler. A sample will then be collected through the sampler's rods with the WSP USA Inc. 5B Oak Branch Drive, Greensboro, North Carolina, USA 27407 Engineering Lic. No. C-2862/Geology Lic. No. C-399 T: +1 336 852-4903 F: +1 336 852-4904 Wsp.com Jaclynne Drummond, Hydrogeologist Project No. 21456818.200 Department of Environmental Quality December 21, 2022 peristaltic pump. The sample will be analyzed for Appendix I VOCs. Pore water samples will continue to be collected annually until there are no exceedances of groundwater standards at the location or the immediately upgradient groundwater sampling location (i.e., MW-19R) for four consecutive events. Annual sampling is proposed based on the relatively low horizontal flow velocities at this site. NCAC 13B. 0545(a)(2): NOTIFICATION TO ALL PERSONS WHO OWN LAND OR RESIDE ON LAND WITHIN THE CONTAMINANT PLUME: The subject property is bisected by the unnamed tributary. The property adjacent to and south of MW-18R2 and MW-19R beyond the unnamed tributary is owned by Rowan County and is undeveloped. Second Creek establishes the southern property boundary and is located approximately 1,035 feet farther south. There are no off -site dwellings within approximately 1800 feet of MW-19R. Based on the adjacent land use and because it does not appear that VOCs occur in groundwater at the property line based on surface water data collected at SW-5, Rowan County does not intend to notify the adjacent landowners at this time. 15A NCAC 13B .0545(a)(3): SUBMISSION OF ASSESSMENT MONITORING WORK PLAN: This document serves as the AMWP Addendum as required by Rule. Once approved by the North Carolina Department of Environmental Quality (NC DEQ), the Plan will be placed in the facility's operating record, and all appropriate government officials will be notified. In order to comply with 15A NCAC 13B .0545 (b), Rowan County will also complete the following activities as described below. 15A NCAC 13B. 0545(b)(2): ANALYSIS OF ADDITIONAL PARAMETERS IN GROUNDWATER: Additional groundwater quality parameters will be analyzed for samples from downgradient monitoring well MW-19R during the January 2023 event in accordance with NCAC 13B. 0545(b)(2). A subset of the compliance monitoring wells may be analyzed for assessment monitoring parameters as allowed in 15A NCAC 13B .0545 (b) (6) and data support limited impacts at this time, which support the subset of wells proposed for Assessment Monitoring. The additional assessment monitoring parameters will include the constituents listed in NC Appendix II; 1,4-dioxane; and the required indicator parameters for C&D landfills (chloride, manganese, sulfate, iron, specific conductance, pH, temperature, alkalinity, total dissolved solids, and tetra hyd rofu ran). One event for the complete NC Appendix II list is allowed in 15A NCAC 13B .0545 (b) (6) and is supported by the fact that many of the NC Appendix II parameters (e.g., PCBs, pesticides, and herbicides) are unlikely to be present based on the acceptable waste in the facility permit. As required by Rule, for any additional NC Appendix II constituent detected at MW-19R, a minimum of four independent samples from the impacted well(s) will be collected and analyzed to establish background for the new constituents. The sampling schedule for assessment monitoring wells and the list of parameters are proposed as follows: NC Appendix II list; 1,4-dioxane; and C&D Indicator NC Appendix/ list; 1,4-dioxane; plus detected NC List (MW-19R) NC Appendix/ list; 1,4-dioxane; plus Appendix II constituents and C&D indicator List detected NC Appendix II constituents and C&D (MW-18R2 & MW-19R) indicator List MW-18R2 & MW-19R %%%I) GOLDER Jaclynne Drummond, Hydrogeologist Project No. 21456818.200 Department of Environmental Quality December 21, 2022 First Semi -Annual Groundwater Second Semi -Annual Groundwater Sampling Event 2024• • Event 2024 NC Appendix 1 list; 1,4-dioxane; plus detected NC NC Appendix / list; 1,4-dioxane; plus detected NC Appendix 11 constituents and C&D indicator List Appendix 11 constituents and C&D indicator List (MW-19R) I(MW-19R) Upon completion of each of the background sampling events, semi-annual reports will be submitted to the Division. Upon completion of the fourth and final background sampling event, a report sealed by a licensed geologist will be submitted to NC DEQ in accordance with 15A NCAC .0545(b)(7). The concentrations of NC Appendix II constituents for each background monitoring event will be compared to established 15A NCAC 02L. 0202 groundwater quality standards (NC 2L Standards). In the case of metals, comparisons will also be made to background concentrations. Pending the results of background sampling results, Rowan County may petition the NC DEQ to return to a Detection Monitoring Program [15A NCAC 13B .0545(b)(9)], request selective Assessment Monitoring for a subset of NC Appendix II constituents for analysis [15A NCAC .0545(b)(6)], and/or will begin the process to implement Assessment of Corrective Measures [15A NCAC 13B .0545(c)]. In summary, Rowan County will begin the Assessment Monitoring Program at the Rowan County C&D Landfill to include MW-19R beginning with the next semi-annual groundwater sampling event in Winter 2022 as described in this addendum. The additional assessment activities described in this addendum will be initiated upon final approval by the NC DEQ. If you have any questions regarding the implementation of the Assessment Monitoring Work Plan, please contact the undersigned at 336-852-4903. Sincerely, WSP USA INC. Darren Cox Rachel P. Kirkman, PG Associate Consultant, Environmental Scientist Director, Geologist CC: Craig Powers, Director of Engineering and Environmental Services, 1102 N. Long Street Extension, craig.powers@rowancountync.gov. Jeff Boyd, Landfill Manager, 789 Campbell Road, Woodleaf, NC 27054 Mike Plummer, PE, HDR, 440 South Church Street, Suite 1000 Charlotte, INC 28202, (704) 338 6843, michael.plummer@hdrinc.com. (Electronic Copy) Attachments: Table 1 - Summary of Detected Organic Constituents in Groundwater Figure 1 - Proposed Pore Water Sampling Locations with Groundwater Surface Contours — August 16, 2022 https://golderassociates.sharepoint.com/sites/163204/project files/5 technical work/phase 300 general consulting/assessment monitoring work plan 2023/d raft/21456818.002: 001-r-rev0-rc_amwp.docx W,I) GOLDER December 2022 Project No. 21456818.200 Table 1 Summary of Detected Constituents in Groundwater for the C&D Landfill Rowan County Landfill (Active MSW and Closed C&D Facilities) Permit 80-03 C&D Monitoring Wells Detected Monitoring Constituents/Analytes Units Sample Date MDL MRL SWS Reporting Limit Blanks Upgradient Downgradient MW-17 MW-18 MW-18R MW-18R2 MW-19 MW-19R Acetone ug/L 11 /04/05 -- -- -- N D N D -- -- N D -- -- NC2L = 6000 ug/L ug/L 12/12/05 -- -- -- ND ND -- -- ND -- No EPA MCL ug/L 12/13/05 -- -- -- ND ND -- -- ND -- -- ug/L 12/22/05 -- -- -- ND ND -- -- ND -- -- ug/L 12/30/05 -- -- 20 ND ND -- -- ND -- ND ug/L 09/26/06 -- -- 100 ND ND -- -- ND -- ND ug/L 09/26/06 -- -- 100 ND ND ND -- ND -- ND ug/L 01/31/07 -- -- 100 ND ND -- -- ND -- ND ug/L 01/31/07 -- -- 100 ND ND ND -- ND -- ND ug/L 07/12/07 -- -- 100 ND ND -- -- ND -- 0.93 J ug/L 07/12/07 -- -- 100 ND ND ND -- ND -- ND ug/L 08/06/07 -- -- 100 -- -- ND -- -- -- ND ug/L 08/06/07 -- -- 100 ND ND ND -- ND -- 0.93 J ug/L 01/17/08 -- -- 100 ND -- ND -- ND -- ND ug/L 01/17/08 -- -- 100 ND ND ND -- ND -- ND ug/L 07/30/08 -- -- 100 5.2 J -- ND -- ND -- ND ug/L 01 /22/09 -- -- 100 ND -- ND -- ND -- ND ug/L 07/14/09 -- -- 100 ND -- ND -- ND -- ND ug/L 01/07/10 -- -- 100 ND -- ND -- ND -- ND ug/L 07/20/10 -- -- 100 ND -- ND -- ND -- ND ug/L 01/31/11 -- -- 100 ND -- ND -- ND -- ND ug/L 07/18/11 -- -- 100 ND -- ND -- ND -- ND ug/L 01/25/12 -- -- 100 ND -- ND -- ND -- ND ug/L 07/19/12 -- -- 100 ND -- ND -- ND -- ND ug/L 01/30/13 -- -- 100 ND -- ND -- ND -- ND ug/L 07/15/13 -- -- 100 ND -- ND -- ND -- ND ug/L 01/27/14 -- -- 100 ND -- ND -- ND -- ND ug/L 07/14/14 -- -- 100 ND -- ND -- ND -- ND ug/L 01/20/15 1.2 -- 100 ND -- ND -- ND -- -- ug/L 07/23/15 1.2 -- 100 ND -- ND -- ND -- ND ug/L 01/12/16 1.2 -- 100 ND -- ND -- ND -- ND ug/L 08/01/16 1.2 -- 100 ND -- ND -- ND -- ND ug/L 01/17/17 10 -- 100 ND -- ND -- ND -- ND ug/L 07/26/17 10 -- 100 ND -- ND -- ND -- ND ug/L 02/20/18 10 -- 100 ND -- ND -- ND -- ND ug/L 08/08/18 10 20 -- ND -- ND -- ND -- ND ug/L 01/15/19 10 20 -- ND -- ND -- ND -- ND ug/L 08/15/19 10 20 -- ND -- ND -- ND -- ND ug/L 01/13/20 10 20 -- ND -- ND -- ND -- ND ug/L 08/10/20 10 20 -- ND -- ND -- ND -- ND u g/L 01 /26/21 10 20 -- ND -- ND -- ND -- ND ug/L 08/27/21 10 20 -- ND -- -- ND -- ND 38 ug/L 02/09/22 10 20 -- ND -- -- ND -- ND ND ug/L 08/15/22 10 20 -- ND -- -- ND -- ND -- X%till GOLDER Page 1 of 5 December 2022 Project No. 21456818.200 Table 1 Summary of Detected Constituents in Groundwater for the C&D Landfill Rowan County Landfill (Active MSW and Closed C&D Facilities) Permit 80-03 C&D Monitoring Wells Detected Monitoring Constituents/Analytes Units Sample Date MDL MRL SWS Reporting Limit Blanks Upgradient Downgradient MW-17 MW-18 MW-18R MW-18R2 MW-19 MW-19R ug/L 08/27/21 3.5 10 -- N D -- -- N D -- N D N D Benzene ug/L 01/31/07 -- -- 3 ND ND -- -- ND -- ND NC 2L = 1 ug/L ug/L 07/12/07 -- -- 1 ND ND -- -- ND -- ND EPA MCL = 5 ug/L ug/L 08/06/07 -- -- 1 -- -- ND -- -- -- ND ug/L 01/17/08 -- -- 1 ND -- ND -- ND -- ND ug/L 07/30/08 -- -- 1 ND -- ND -- ND -- ND ug/L 01 /22/09 -- -- 1 ND -- ND -- ND -- ND ug/L 07/14/09 -- -- 1 ND -- ND -- ND -- ND ug/L 01/07/10 -- -- 1 ND -- ND -- ND -- ND ug/L 07/20/10 -- -- 1 ND -- ND -- ND -- ND ug/L 01/31/11 -- -- 1 ND -- ND -- ND -- ND ug/L 07/18/11 -- -- 1 ND -- ND -- ND -- ND ug/L 01/25/12 -- -- 1 ND -- ND -- ND -- ND ug/L 07/19/12 -- -- 1 ND -- ND -- ND -- ND ug/L 01/30/13 -- -- 1 ND -- ND -- ND -- ND ug/L 07/15/13 -- -- 1 ND -- ND -- ND -- ND ug/L 01/27/14 -- -- 1 ND -- ND -- ND -- ND ug/L 07/14/14 -- -- 1 ND -- ND -- ND -- ND ug/L 01/20/15 -- -- 1 ND -- ND -- ND -- -- ug/L 07/23/15 0.15 -- 1 ND -- ND -- ND -- ND ug/L 01/12/16 0.15 -- 1 ND -- ND -- ND -- ND ug/L 08/01/16 0.15 -- 1 ND -- ND -- 1.3 -- ND (Verification Event) ug/L 09/01/16 0.15 -- 1 -- -- -- -- ND -- -- ug/L 01/17/17 0.15 -- 1 ND -- ND -- ND -- ND ug/L 07/26/17 0.15 -- 1 ND -- ND -- ND -- ND ug/L 02/20/18 0.15 -- 1 ND ND -- -- ND -- ND ug/L 08/08/18 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 01/15/19 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 08/15/19 0.15 1.0 -- ND -- 2.1 -- 4.5 -- ND (Verification Event) ug/L 10/03/19 0.15 1.0 -- ND -- 2.3 -- 1.0 -- ND ug/L 01/13/20 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 08/10/20 0.15 1.0 -- ND -- 1.1 -- 5.8 -- ND (Verification Event) ug/L 10/19/20 0.15 1.0 -- -- -- 1.4 -- 3.2 -- ND ug/L 01 /26/21 0.15 1.0 -- ND -- 0.79 J -- 7.4 -- ND ug/L 08/27/21 0.15 1.0 -- ND -- -- 4.1 -- 0.75 J ND (Verification Event) ug/L 10/08/21 0.15 1.0 -- -- -- -- 3.1 -- -- ND ug/L 02/09/22 0.15 1.0 -- ND -- -- 4.5 -- 0.93 J ND ug/L 08/15/22 0.15 1.0 -- ND -- -- 5.5 -- 1.4 ND (Verification Event) ug/L 10/05/22 0.15 1.0 -- -- -- -- -- -- 2.1 ND cis-1,2-Dichloroethene ug/L 09/26/06 -- -- 5 ND ND -- -- ND -- ND NC 2L = 70 ug/L ug/L 01/31/07 -- -- 5 ND ND -- -- ND -- ND EPA MCL = 70 ug/L ug/L 07/12/07 -- -- 5 ND ND -- -- ND -- ND ug/L 08/06/07 -- -- 5 -- -- ND -- -- -- ND ug/L 01/17/08 -- -- 5 ND -- ND -- ND -- ND ug/L 07/30/08 -- -- 5 ND -- ND -- ND -- ND ug/L 01 /22/09 -- -- 5 ND -- ND -- ND -- ND ug/L 07/14/09 -- -- 5 ND -- ND -- ND -- ND ug/L 01/07/10 -- -- 5 ND -- ND -- ND -- ND ug/L 07/20/10 -- -- 5 ND -- ND -- ND -- ND ug/L 01/31/11 -- -- 5 ND -- ND -- ND -- ND ug/L 07/18/11 -- -- 5 ND -- ND -- ND -- ND ug/L 01/25/12 -- -- 5 ND -- ND -- ND -- ND ug/L 07/19/12 -- -- 5 ND -- ND -- ND -- ND ug/L 01/30/13 -- -- 5 ND -- ND -- ND -- ND ug/L 07/15/13 -- -- 5 ND -- ND -- ND -- ND ug/L 01/27/14 -- -- 5 ND -- 0.69 J -- ND -- ND ug/L 07/14/14 -- -- 5 ND -- 1.7 J -- ND -- ND ug/L 01/20/15 0.15 -- 5 ND -- ND -- ND -- -- ug/L 07/23/15 0.15 -- 5 ND -- 1.2 J -- ND -- ND ug/L 01/12/16 0.15 -- 5 ND -- ND -- ND -- ND ug/L 08/01/16 0.15 -- 5 ND -- 0.89 J -- ND -- ND ug/L 01/17/17 0.15 -- 5 ND -- ND -- ND -- ND ug/L 07/26/17 0.15 -- 5 ND -- ND -- ND -- ND ug/L 02/20/18 0.15 -- 5 ND -- ND -- ND -- ND ug/L 08/08/18 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 01/15/19 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 08/15/19 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 01/13/20 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 08/10/20 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 01/26/21 0.15 1.0 -- ND -- ND -- ND -- ND ug/L 08/27/21 0.15 1.0 -- ND -- -- ND -- ND ND ug/L 02/09/22 0.15 1.0 -- ND -- -- ND -- ND ND u g/L 08/ 15/22 0.15 1.0 -- ND -- -- ND -- ND ND X%till GOLDER Page 2 of 5 December 2022 Project No. 21456818.200 Table 1 Summary of Detected Constituents in Groundwater for the C&D Landfill Rowan County Landfill (Active MSW and Closed C&D Facilities) Permit 80-03 C&D Monitoring Wells Detected Monitoring Constituents/Analytes Units Sample Date MDL MRL SWS Reporting Limit Blanks Upgradient Downgradient MW-17 MW-18 MW-18R MW-18R2 MW-19 MW-19R 1,4-Dioxane ug/L 08/08/18 25 60 -- ND -- ND -- ND -- ND NC 2L = 3 ug/L, No EPA MCL ug/L 01/15/19 1.2 2.0 -- ND -- 4.6 -- ND -- ND (Verification Event) ug/L 02/21/19 1.2 2.0 -- ND -- 5.0 -- ND -- ND ug/L 08/15/19 1.2 2.0 -- ND -- 26 -- 25 -- ND ug/L 01/13/20 1.2 2.0 -- ND -- 6.3 -- 7.2 -- ND ug/L 08/10/20 0.80 2.0 -- ND -- 15 -- 29 -- ND ug/L 01 /26/21 0.80 2.0 -- ND -- 14 -- 38 -- ND ug/L 08/27/21 0.80 2.0 -- 1.5 J -- -- 31 -- 5.2 ND ug/L 02/09/22 0.80 2.0 -- ND -- -- 31 -- 3.3 ND ug/L 08/15/22 0.80 2.0 -- 0.85 J -- -- 41 -- 7.2 ND Tetrahydrofuran ug/L 01/31/11 -- -- -- ND -- ND -- ND -- ND NC 2L = 2000 ug/L ug/L 07/18/11 -- -- -- ND -- ND -- ND -- ND No EPA MCL ug/L 07/18/11 -- -- -- ND -- ND -- ND -- ND ug/L 01/25/12 -- -- -- ND -- ND -- ND -- ND ug/L 07/19/12 -- -- -- ND -- ND -- ND -- ND ug/L 01/30/13 -- -- -- ND -- ND -- ND -- ND ug/L 07/15/13 -- -- -- ND -- 2.4 -- ND -- ND ug/L 01/27/14 -- -- -- ND -- 1.3 -- ND -- ND ug/L 07/14/14 -- -- -- ND -- ND -- ND -- ND ug/L 01/20/15 0.8 -- -- ND -- ND -- ND -- -- ug/L 07/23/15 0.8 -- -- ND -- ND -- ND -- ND ug/L 01/12/16 0.8 -- -- ND -- ND -- ND -- ND ug/L 08/01/16 0.8 -- -- ND -- ND -- ND -- ND ug/L 01/17/17 0.8 -- -- ND -- ND -- 2.5 -- ND ug/L 07/26/17 0.8 -- -- ND -- ND -- ND -- ND ug/L 02/20/18 0.53 -- -- ND -- ND -- ND -- ND ug/L 08/08/18 0.53 1.0 -- ND -- ND -- 3.2 -- ND ug/L 01/15/19 0.53 1.0 -- ND -- ND -- ND -- ND ug/L 08/15/19 0.53 1.0 -- ND -- ND -- ND -- ND ug/L 01/13/20 0.53 1.0 -- ND -- ND -- ND -- ND ug/L 08/10/20 0.53 1.0 -- ND -- 4.5 -- ND -- ND u g/L 01 /26/21 0.53 1.0 -- ND -- ND -- ND -- ND ug/L 08/27/21 0.53 1.0 -- ND -- -- 21 -- 10 ND ug/L 02/09/22 0.53 1.0 -- ND -- -- ND -- ND ND ug/L 08/15/22 0.53 1.0 -- ND -- -- 14 -- ND ND Chloride mg/L 01 /31 /07 -- -- -- 11.0 6.0 -- -- 9.0 -- ND NC 2L = 250 mg/L mg/L 07/12/07 -- -- -- 4.8 2.8 -- -- 2.4 -- ND EPA MCL = 250 ug/L mg/L 08/06/07 -- -- -- -- -- 2.9 -- -- -- ND mg/L 01/17/08 -- -- -- 12 -- 5.2 B -- 7.5 B -- 2.1 mg/L 07/30/08 -- -- -- 9.6 -- 3.8 B -- 5.6 -- 0.95 mg/L 01 /22/09 -- -- -- 7.5 -- 2.6 J -- 3.2 J -- ND mg/L 07/14/09 -- -- -- 9.4 B -- 5.8 B -- 6.6 B -- 2.2 mg/L 01 /07/10 -- -- -- 9.1 -- 6.0 -- 6.0 -- ND mg/L 07/20/10 -- -- -- 9.0 -- 6.8 -- 6.6 -- ND mg/L 01/31/11 -- -- -- 8.7 B -- 9.4 -- 5.9 B -- 1.8 mg/L 07/18/11 -- -- -- 7.8 -- 8.9 -- 5.6 B -- 1.5 mg/L 01/25/12 -- -- -- 7.5 -- 17 -- 5.1 B -- 1.4 mg/L 07/19/12 -- -- -- 5.6 -- 7.1 -- 4.6 -- ND mg/L 01/30/13 -- -- -- 7.2 B -- 22 -- 4.6 B -- 1.5 mg/L 07/15/13 -- -- -- 6.6 -- 35 -- 4.5 J -- ND mg/L 01 /27/14 -- -- -- 6.3 -- 22 -- 3.9 J -- ND mg/L 07/14/14 -- -- -- 5.8 -- 8.5 -- 5.8 -- ND mg/L 01/20/15 2.2 -- -- 6.5 -- 21 -- 5.4 -- -- mg/L 07/23/15 2.2 -- -- 6.5 -- 12 -- 6.1 -- -- mg/I 01/12/16 2.2 -- -- 5.6 -- 35 -- 2.3 J -- -- mg/L 08/01 /16 0.29 -- -- 4.6 J -- 16 -- 5.5 -- ND mg/L 01/17/17 2.2 -- -- 5.3 -- 30 -- 4.7 J -- ND mg/L 07/26/17 2.2 -- -- 5.3 -- 23 -- 5.0 -- ND mg/L 02/20/18 2.2 -- -- 5 -- 32 -- 2.8 J -- ND mg/L 08/08/18 2.2 5 -- 3.6 J -- 25 -- 2.9 J -- ND mg/L 01/15/19 2.2 5 -- 3.3 J -- 33 -- ND -- ND (Verification Event) mg/L 02/21/19 2.2 5 -- -- -- 33 -- -- -- ND mg/L 08/15/19 2.2 5 -- 4.0 J -- 92 -- 11 -- ND mg/L 01/13/20 2.2 5 -- 5.4 -- 39 -- 5.3 -- ND mg/L 08/10/20 2.2 5 -- 3.6 J -- 71 -- 43 -- ND mg/L 01 /26/21 2.2 5 -- 3.9 J -- 52 -- 50 -- ND mg/L 08/27/21 2.2 5 -- 4.6 J -- -- 110 -- 5.9 ND mg/L 02/09/22 2.2 5 -- 4.8 J -- -- 110 -- 5.7 ND mg/L 08/15/22 2.2 5 -- 4.5 J -- -- 120 -- 6.1 ND X%till GOLDER Page 3of5 December 2022 Project No. 21456818.200 Table 1 Summary of Detected Constituents in Groundwater for the C&D Landfill Rowan County Landfill (Active MSW and Closed C&D Facilities) Permit 80-03 C&D Monitoring Wells Detected Monitoring Constituents/Analytes Units Sample Date p MDL MRL SWS Reporting Limit Blanks Upgradient Downgradient MW-17 MW-18 MW-18R MW-18R2 MW-19 MW-19R Total Dissolved Solids mg/L 01/31/07 -- -- -- 120 108 -- -- 84 -- ND NC 2L = 500 mg/L mg/L 07/12/07 -- -- -- 80 62 -- -- 72 -- ND No EPA MCL mg/L 08/06/07 -- -- -- -- -- 90 -- -- -- ND mg/L 01/17/08 -- -- -- 70 -- 94 -- 88 -- ND mg/L 07/30/08 -- -- -- 110 -- 48 -- 96 -- ND mg/L 01 /22/09 -- -- -- 66 -- 520 -- 52 -- ND mg/L 07/14/09 -- -- -- 96 -- 100 -- 100 -- ND mg/L 01/07/10 -- -- -- 80 -- 60 -- 74 -- ND mg/L 07/20/10 -- -- -- 74 -- 72 -- 68 -- ND mg/L 01 /31 /11 -- -- -- 94 -- 100 -- 44 -- ND mg/L 07/18/11 -- -- -- 54 -- 80 -- 70 -- ND mg/L 01/25/12 -- -- -- 56 -- 82 -- 56 -- ND mg/L 07/19/12 -- -- -- 78 -- 70 -- 66 -- ND mg/L 01/30/13 -- -- -- 32 -- 140 -- 36 -- ND mg/L 07/15/13 -- -- -- 56 -- 250 -- 48 -- ND mg/L 01/27/14 -- -- -- 52 -- 130 -- 40 -- ND mg/L 07/14/14 -- -- -- 34 -- 68 -- 48 -- ND mg/L 01 /20/15 10 -- -- 46 -- 200 -- 58 -- -- mg/L 07/23/15 50 -- -- 52 -- 88 -- 68 -- -- mg/L 01/12/16 50 -- -- 72 -- 300 -- ND -- -- mg/L 08/01/16 50 -- -- 56 -- 170 -- 80 -- ND mg/L 01/17/17 50 -- -- ND -- 320 -- 64 -- ND mg/L 07/26/17 50 -- -- ND -- 210 -- ND -- ND mg/L 02/20/18 50 -- -- 66 -- 380 -- 72 -- ND mg/L 08/08/18 50 50 -- ND -- 240 -- ND -- ND mg/L 01/15/19 50 50 -- 60 -- 520 -- 110 -- ND (Verification Event) mg/L 02/21/19 50 50 -- -- -- 690 -- -- -- ND mg/L 08/15/19 50 50 -- ND -- 270 -- 110 -- ND mg/L 01/13/20 50 50 -- 82 -- 660 -- 90 -- ND mg/L 08/10/20 50 50 -- ND -- 410 -- 160 -- ND mg/L 01 /26/21 50 50 -- 70 -- 550 -- 240 -- ND mg/L 08/27/21 50 50 -- 76 -- -- 1200 -- 100 ND (Verification Event) mg/L 10/08/21 50 50 -- -- -- -- 1200 -- -- ND mg/L 02/09/22 50 50 -- 64 -- -- 1400 -- 86 -- mg/L 08/15/22 50 50 -- ND -- -- 1600 -- 110 -- Sulfate mg/L 01/31/07 -- -- -- ND 1.3 J -- -- 1.5 J -- ND NC 2L = 250 mg/L mg/L 07/12/07 -- -- -- 0.91 1.6 -- -- 1.2 -- ND No EPA MCL mg/L 08/06/07 -- -- -- -- -- 3.7 B -- -- -- 3.2 J mg/L 01/17/08 -- -- 250 1.0 J -- 0.99 J -- 1.1 J -- ND mg/L 07/30/08 -- -- 250 1.6 J -- 2.4 J -- 1.5 J -- ND mg/L 01/22/09 -- -- 250 ND -- 2.7 J -- 2.2 J -- ND mg/L 07/14/09 -- -- 250 ND -- 2.9 J -- 3.2 J -- ND mg/L 01/07/10 -- -- 250 ND -- 2.6 J -- 2.5 J -- ND mg/L 07/20/10 -- -- 250 ND -- 3.0 J -- 2.8 J -- ND mg/L 01 /31 /11 -- -- 250 1.8 J -- 3.4 J -- 3.1 J -- ND mg/L 07/18/11 -- -- 250 1.7 J -- 3.6 J -- 2.5 J -- ND mg/L 01/25/12 -- -- 250 1.4 J -- 7.4 J -- 2.7 J -- ND mg/L 07/19/12 -- -- 250 2 J -- 9.2 J -- 2.4 J -- ND mg/L 01/30/13 -- -- 250 1.7 J -- 12 J -- 2.8 J -- ND mg/L 07/15/13 -- -- 250 1.6 B -- 70 J -- 4.1 B -- 1.5 J mg/L 01 /27/14 -- -- 250 ND -- 33 J -- 4 J -- ND mg/L 07/14/14 -- -- 250 ND -- 21 J -- ND -- ND mg/L 01 /20/15 2.9 -- 250 ND -- 63 J -- ND -- -- mg/L 07/23/15 2.9 -- 250 ND -- 16 J -- ND -- -- mg/L 01/12/16 2.9 -- 250 ND -- -- -- 5 J -- -- mg/L 01/12/16 2.9 -- 250 -- -- 110 J -- -- -- -- mg/L 08/01/16 0.07 -- 250 0.12 J -- 48 J -- 1 J -- ND mg/L 01/17/17 2.9 -- 250 ND -- 110 J -- ND -- ND mg/L 07/26/17 2.9 -- 250 ND -- 69 J -- ND -- ND mg/L 02/20/18 2.9 -- 250 ND -- -- -- 3 J -- ND mg/L 02/20/18 5.8 -- 250 -- -- 110 J -- -- -- ND mg/L 08/08/18 2.9 5 -- ND -- 87 -- 3 J -- ND mg/L 01/15/19 2.9 5 -- ND -- 170 -- 6.8 -- ND (Verification Event) mg/L 02/21/19 2.9 5 -- -- -- 240 -- -- -- ND mg/L 08/15/19 2.9 5 -- ND -- 15 -- 6.5 -- ND mg/L 01 /13/20 2.9 5 -- ND -- 210 -- 6.3 -- ND mg/L 08/10/20 2.9 5 -- ND -- 100 -- 7.3 -- ND mg/L 01 /26/21 2.9 5 -- ND -- 160 -- 7.4 -- ND mg/L 08/27/21 2.9 5 -- ND -- -- 270 -- ND ND mg/L 02/09/22 2.9 5 -- ND -- -- 290 -- ND ND mg/L 1 08/15/22 1 2.9 1 5 1-- ND -- -- 290 -- ND ND X%till GOLDER Page 4 of 5 December 2022 Project No. 21456818.200 Table 1 Summary of Detected Constituents in Groundwater for the C&D Landfill Rowan County Landfill (Active MSW and Closed C&D Facilities) Permit 80-03 C&D Monitoring Wells Detected Monitoring Constituents/Analytes Units Sample Date p MDL MRL SWS Reporting Limit Blanks Upgradient Downgradient MW-17 MW-18 MW-18R MW-18R2 MW-19 MW-19R Total Alkalinity as CaCO3 mg/L 01/31/07 -- -- -- 32 38 -- -- 22 -- ND No Standard mg/L 07/12/07 -- -- -- 16 B 49 -- -- 26 B -- 6.4 J No EPA MCL mg/L 08/06/07 -- -- -- -- -- 6.0 -- -- -- -- mg/L 01/17/08 -- -- -- 9.8 J -- 26 -- 25 -- ND mg/L 07/30/08 -- -- -- 18 B -- 27 B -- 24 B -- 8.6 J mg/L 01 /22/09 -- -- -- 24 -- 26 -- 29 -- ND mg/L 07/14/09 -- -- -- 11 J -- 22 -- 26 -- ND mg/L 01/07/10 -- -- -- 8.7 J -- 22 -- 23 -- ND mg/L 07/20/10 -- -- -- 11 J -- 33 -- 26 -- ND mg/L 01 /31 /11 -- -- -- 18 -- 29 -- 14 J -- ND mg/L 07/18/11 -- -- -- ND -- 25 -- 23 -- ND mg/L 01/25/12 -- -- -- 12 -- 26 -- 17 -- ND mg/L 07/19/12 -- -- -- 14 -- 33 -- 21 -- ND mg/L 01/30/13 -- -- -- 27 -- 33 -- 24 -- ND mg/L 07/15/13 -- -- -- 31 -- 25 -- 49 -- ND mg/L 01/27/14 -- -- -- 40 -- 37 -- 39 -- ND mg/L 07/14/14 -- -- -- 17 -- 43 -- 24 -- ND mg/L 01 /20/15 14 -- -- 34 -- 61 -- 38 -- -- mg/L 07/23/15 14 -- -- 37 -- 47 -- 43 -- -- mg/L 01 /12/16 14 -- -- 34 -- 110 -- 24 -- -- mg/L 08/01/16 14 -- -- 35 -- 90 -- 48 -- ND mg/L 01/17/17 14 -- -- 42 -- 130 -- 44 -- ND mg/L 07/26/17 14 -- -- 34 -- 91 -- 41 -- ND mg/L 02/20/18 14 -- -- 29 -- 130 -- 29 -- ND mg/L 08/08/18 14 15 -- 35 -- 120 -- 32 -- ND mg/L 01/15/19 14 15 -- 25 -- 190 -- 32 -- ND (Verification Event) mg/L 02/21/19 14 15 -- -- -- 250 -- -- -- ND mg/L 08/15/19 14 15 -- 25 -- 85 -- 82 -- ND mg/L 01/13/20 14 15 -- 37 -- 240 -- 42 -- ND mg/L 08/10/20 14 15 -- 16 -- 150 -- 110 -- ND mg/L 01 /26/21 14 15 -- 15 -- 170 -- 100 -- ND mg/L 08/27/21 14 15 -- 22 -- -- 550 -- 54 ND mg/L 02/09/22 14 15 -- 20 -- -- 750 -- 61 -- mg/L 08/15/22 14 15 -- 22 -- -- 940 -- 65 -- Notes: ug/L = micrograms per liter mg/L = milligrams per liter S.U. = Standard Units NTU = Nephelometric Turbidity Units mV = millivolts ND = Not detected at the stated reporting limit pS/cm = microsiemens per centimeter -- = no data available or not established B = blank -qualified result J = Prior to the August 2018 event, J flags are estimated values below the SWS Reporting limit. Beginning with the August 2018 event, J flags are estimated values between MDL and MRL. Blanks = field, trip and method blanks Shaded = Concentrations above the current NC 2L or Solid Waste Section Groundwater Protection Standards have been shaded SWS Reporting Limit = NCPQL prior to 2007 and NCSWSL starting in 01/31/07 MDL = Laboratory method detection limit MRL = Laboratory method reporting limit 1) Historical data prior to September 2006 provided by Rowan County. 2) MW-18 was replaced by MW-18R after the July 2007 sampling event. 3) The following dilutions were noted for the August 2022 event: antimony and thallium (2x) all wells; sulfate and chloride at MW-118R (5x). Monitoring Wells MW-18R2 and MW-119R were installed on May 13-14, 2021 X%till GOLDER Page 5of5 CURRRENT LANDFILL ENTRANCE EXISTING SEDIMENT BASIN IF 0001 1�000 j EXISTING SEDIMENT BASS �, I MW-1 'l �� I [;697.57 MMW-6Ad\ �\ 1 �0,04 6 5.9�0 � i'l' 6� I MMW-7 - 4 I �I $oI� 6 I MW-25 O I 673.42 SCALE HOUSE .01 LEGEND W /`. EXISTING SEDIMENT BASIN 250 0 250 500 SCALE FEET NOTES 1. TOPOGRAPHIC CONTOUR INTERVAL = 2 FEET. 2. GROUNDWATER SURFACE CONTOUR INTERVAL = 10 FEET. 3. GROUNDWATER ELEVATIONS MEASURED ON AUGUST 24, 2021. 4. GROUNDWATER CONTOURS ARE BASED ON LINEAR INTERPOLATION BETWEEN AND EXTRAPOLATION FROM KNOWN DATA, TOPOGRAPHIC CONTOURS, AND KNOWN FIELD CONDITIONS. THEREFORE, GROUNDWATER CONTOURS MAY NOT REFLECT ACTUAL GROUNDWATER CONDITIONS. 5. GROUNDWATER CONTOUR LINES SHOW THE WATER TABLE SHAPE AND ELEVATION. THESE CONTOURS ARE INFERRED LINES FOLLOWING THE GROUNDWATER SURFACE AT A CONSTANT ELEVATION ABOVE SEA LEVEL. THE GROUNDWATER FLOW DIRECTION IS GENERALLY PERPENDICULAR TO THE GROUNDWATER SURFACE CONTOURS, SIMILAR TO THE RELATIONSHIP BETWEEN SURFACE WATER FLOW AND TOPOGRAPHIC CONTOURS. 6. SURFACE WATER MONITORING POINT SW-1 IS APPROXIMATELY 550 FEET OFF THE MAPPING LIMITS SHOWN AND IS COLLECTED FROM SECOND CREEK. 7. MONITORING WELLS MW-18R, MW-19, MW-23A, MW-27A, MW-28 AND MW-6 ARE UTILIZED FOR WATER LEVEL MONITORING ONLY. 8. THE LOCATION OF THE FRENCH DRAIN MONITORING POINT IS APPROXIMATE 9. MW-28R WAS INSTALLED JULY 11, 2017 TO REPLACE MW-28. MW-28 WILL CONTINUE TO BE UTILIZED FOR WATER LEVEL MONITORING. 10. MW-18R2 AND MW-19R WERE INSTALLED IN MAY 2021 TO REPLACE MW-18R AND MW-19, RESPECTIVELY. REFERENCE 1. EXISTING CONDITIONS INSIDE OF DASHED LINE COMPILED BY CARTOGRAPHIC AERIAL MAPPING, INC. USING PHOTOGRAMMETRIC METHODS, FROM AERIAL PHOTOGRAPHY DATED MAY 9, 2021. EXISTING CONDITIONS OUTSIDE OF DASHED LINE PROVIDED BY S&ME ENGINEERING, INC., DATE UNKNOWN. 2. PROPERTY BOUNDARY TAKEN FROM CAD FILE TITLED, "WELLS.DWG," PROVIDED BY HDR INC. CLIENT ROWAN COUNTY, NORTH CAROLINA U _ _ FACILITY BOUNDARY PROJEC-1 SW-3 ROWAN COUNTY ACTIVE AND CLOSED LANDFILLS APPROXIMATE LIMITS OF WASTE PERMIT No. 80-03 t'OhO ` EXISTING TOPOGRAPHIC CONTOURS (2' INTERVALS) ROWAN COUNTY, NORTH CAROLINA I GROUNDWATER SURFACE CONTOURS GROUNDWATER CONTOUR MAP O APPROXIMATE GROUNDWATER FLOW SEGMENT USED TO AUGUST 16, 2022 cov CALCULATE GRADIENT EXISTING GROUNDWATER MONITORING WELL WITH QMW-7 GROUNDWATER ELEVATION CONSULTANT YYYY-MM-DD 2021-09-10 � �1 647.34 \ SURFACE WATER MONITORING POINT DESIGNED TM El SURFACE GOLDEP o � � PREPARED BPG COMPLIANCE METHANE MONITORING POINT ASSESSMENT TO SW-1 REVIEWED CD t (SEE NOTE 6) METHANE MONITORING POINT GOLDER ASSOCIATES NC, INC. APPROVED RPK FRENCH DRAIN MONITORING POINT PROJECT NO. REV. DRAWING O PWS-1 PORE WATER SAMPLING LOCATION 21-456818 0 IL 0