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Home My WebLink About20080868 Ver 2_2022 Reclamation Area Groundwater Data_20230130Alutrien- Feeding the Future - Certified Mail January 30, 2023 Mr. Tom Steffens U.S. Army Corps of Engineers Washington Regulatory Field Office 2407 West 51h Street Washington, North Carolina 27889 Re: PCS Phosphate Company, Inc. 2022 Reclamation Area Groundwater Data Dear Mr. Steffens: Please find on the enclosed CD the 2022 reclamation area groundwater report and data required in 404 Permit No. SAW-2001-10096 Special Condition Q, issued June 10, 2009. It also addresses groundwater sampling required in NCDWR Water Quality Certification No. 2008-0868, version 2.0 Special Condition 12, issued January 15, 2009. This report and data includes results of groundwater monitoring from 14 wells around the R12 reclamation area, seven in the Yorktown Formation and seven in the Castle Hayne Aquifer. Baseline data is from January 2018 — July 2019, and post -blend sampling data is from August 2019-December 2022. Per the attached report, no action is required at this time and we will continue to trend identified parameters as outlined in the March 29, 2019 submittal to David May of the DWR Washington Regional Office. If you have any questions, please contact me at (252) 402-4699 or by email at tyler.peacock@nutrien.com. Since , Tyler A. Peacock Environmental Scientist pc: Kelsey Rowland — DWR, Raleigh w/CD David May— DWR, Washington w/CD Robert Tankard — DWR, Washington w/CD 23-16 w/CD 23-01-004-29 w/CD 1530 NC Hwy 306 South, Aurora, NC USA 27806 RECEIVED FED 6 2023 DEG -WATER RESOURCES 4-51 & BUFFER PERMITTING nutrien.com 1 Effective January 1, 2018, PCs Phosphate Company, Inc. is an indirect subsidiary of Nutrien Ltd. PCS Phosphate Company, Inc. remains the legal operating entity and permittee. 2022 Annual PCS Phosphate Company, Inc. Reclamation Area Groundwater (R12) Report Prepared by: PCS Phosphate Co. Inc. 1530 NC Hwy 306S Aurora, NC 27806 January 2023 Table of Contents I. Background.................................................................................................................................................1 II. Laboratory Analysis...................................................................... ..........1 .................................................. III. Results and Actions..................................................................................................................................1 Figure1: R12 Sampling Location Map.......................................................................................................3 Table 1: Groundwater Analytes: Units, Detection Limits, and 2L Standard..............................................4 IV. Appendices...............................................................................................................................................5 A. Time Series Plots w/trend analysis (Digital- CD)...................................................................................5 B. Raw Analytical Data (Digital-CD)...........................................................................................................5 I. Background PCs Phosphate Company, Inc. (PCs) operates an open pit phosphate mine in Aurora, Beaufort County, NC. Mining began at the site in 1965 to provide raw materials for the operation of on -site chemical plants that produce various phosphate -based acid and fertilizer products. The mining and beneficiation process of the raw ore creates several main by-products: sand tailings and clays that are separated from the ore in the mill process, and phosphogypsum that is generated after the refined ore is reacted with sulfuric acid to create phosphoric acid. As part of the US Army Corps of Engineers (COE) 404 Permit No. SAW-2001-10096 Special Condition Q, issued June 10, 2009, and NC Division of Water Resources (DWR) 401 Water Quality Certification No. 2008-0868, version 2.0 Special Condition 12, issued January 15, 2009, for mining activities, PCs is required to develop and administer a groundwater monitoring program around reclamation areas for the Yorktown Formation (YK) and Castle Hayne (CH) aquifers. Reclamation Area 12 (1112) is the first to be regulated under these requirements. Gypsum/clay blend for reclamation was first introduced into R12 in August 2019. Baseline (pre -blend) data was collected from January 2018 through July 2019. The locations of the sampling wells around R12 are shown on Figure 1. The following is a timeline of events relating to the reclamation area groundwater sampling program: The initial monitoring plan was developed and submitted to the COE and NC DWR on June 10, 2016 and was approved with some modifications in a letter from DWR dated September 1, 2017. 2. Baseline groundwater sampling around R12 began in January 2018. 3. PCS personnel met with DWR staff on March 29, 2019 and submitted a formal package to clarify future action procedures. 4. Gypsum/clay blend was introduced into R12 and monthly post -blend sampling began in August 2019. 5. Well installation and baseline sampling for R13 began in spring/summer of 2022. II. Laboratory Analysis All lab analyses except radionuclides have been conducted by Environment 1 Inc. in Greenville, NC, a contracted external state -certified laboratory. Analytes include general water quality parameters, total and dissolved metals, and radionuclides (Table 1). Analysis of radionuclides were sub -contracted to Florida Radiochemistry Services, Inc. in Orlando, FL by Environment 1. Table 1 also shows the NC 2L groundwater standard for each parameter that has a standard, and the laboratory detection limit for each parameter. III. Results and Actions Analysis results are found in Appendix A. Raw analytical data is included in Appendix B. Time series plots for all parameters and wells are presented in this report. Baseline (black) and post - blend (red) data are plotted together, with a median and Stuart- Cox trend test presented for each where applicable. Date of blend introduction is marked by a vertical red dashed line. Parameters that are completely censored, i.e. every data point is the detection limit, will have the time series, baseline median, post -blend median, and detection limit appear overlaid as a horizontal line at that value (Appendix A). An increasing Sulfate trend has been observed in the Yorktown Formation #3 well starting in mid-2021 and has exceeded the 250 mg/L 2L Standard once in late 2022, followed by a decrease in the following two monthly samples. We will continue trend analysis of this parameter as outlined in the March 29, 2019 letter. Some parameters have exceeded the 2L standard for only pre -blend samples: Parameter CH Wells YK Wells Chromium CH5 Gross Alpha CH4, CH7 YK1, YK2, YK7 Several other parameters have exceeded 2L standards in both pre- and post -blend samples: Parameter CH Wells YK Wells Chloride CH7 YK1, YK2, YK6 Sulfate YK1, YK2, YK6 Total Dissolved Residue CH1, CH2, CH7 YK1, YK2, YK6 pH YK1, YK6 Gross Alpha YK6 An increasing Chloride trend has been observed in Castle Hayne well #7, and it has exceeded the 250 mg/L baseline/2L Standard post -blend. Along with Chloride, the Sodium and Total Dissolved Residue concentrations have also continued their increasing trends in the same well. Total Dissolved Residue concentrations have been above the 500 mg/L 2L standard for all baseline and post -blend samples. Trend analysis shows that these three parameters have all seen statistically significant increasing trends (Stuart -Cox test) since the beginning of baseline sampling, 18 months before blend was initially placed in R12 (Appendix A). Increasing Total Dissolved Residue trends and exceedances of the 500 mg/L 2L Standard have also been seen in Yorktown Formation #3, 4, and 5 wells. Increasing Chloride trends have been seen post -blend in YK3, YK4 and YKS; however, only YK4 has exceeded the 2L standard. Also, Chloride concentrations in YK1 and YK2 have been orders of magnitude above the 2L standard and the other wells in both baseline and post -blend data. These are accompanied by increasing Sodium trends in YK3 and YK4 for post -blend data and high baseline and post -blend Sodium concentrations in YK1 and YK2 (Appendix A). Other Yorktown Formation and Castle Hayne wells have exhibited concurrent elevated concentrations of Total Dissolved Residue, Sodium, and Chloride, and we believe that these correlated increases in are unrelated to blend introduction in the reclamation areas, as they are not constituents of the gypsum - clay blend and are instead due to existing regional salinization patterns in these aquifers in the coastal zone of North Carolina. For these parameters, we believe no remedial action is or will be required; however, they will continue to be trended and reported. 2 Per the March 29, 2019 future action procedure letter, no immediate action is required other than continued 3-year trend analysis of the identified parameters. Figure 1: R12 Sampling Location Map r r <r Table 1: Groundwater Analytes: Units, Detection Limits, and 2L Standard Parameter Units 2L Standard Detection Limit pH 6.5-8.5 - Nitrate Nitrogen as N mg/L 10 0.04 Total Phosphorus as P mg/L - 0.04 Chloride mg/L 250 - Fluoride mg/L 2 - Total Dissolved Residue mg/L 500 - Sulfate mg/L 250 - Arsenic ug/L 10 5 Arsenic, Total Dissolved ug/L 10 5 Cadmium ug/L 2 1 Cadmium, Total Dissolved ug/L 2 1 Chromium ug/L 10 5 Chromium, Total Dissolved ug/L 10 5 Lead ug/L 15 5 Lead, Total Dissolved ug/L 15 5 Nickel ug/L 100 10 Nickel, Total Dissolved ug/L 100 10 Sodium mg/L - - Zinc ug/L 1000 10 Zinc, Total Dissolved ug/L 1000 10 Gross Alpha pCi/L 15 Varies Radium-226 pCi/L - Varies Radium-228 pCi/L - Varies Uranium mg/L - Varies IV. Appendices A. Time Series Plots w/trend analysis (Digital- CD) B. Raw Analytical Data (Digital -CD)