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Home My WebLink About12505 AL6210020776 045 12-29-2023 CORS CJM 2022 Annual Long-Term Monitoring Report Response DANCER.LEREUR ADEM �Y'M GO VERNOR OVERNOR Alebann bell of anvlmmmenlel Mana9nmeM etlem.918h8m8.gOv 1400 coliseum Blvd.36110 2400 a Post Office Box 301463 Montgomery,Alabama 36130-1463 December 29,2023 (334)271-7700 • FAX(334)271-7950 ELECTRONICALLY TRANSMITTED Mrs. Julie Majors Environmental and Natural Resources Division Directorate of Public Works IMSE-RCK-PWE, Bldg 1121 Fort Novosel,Alabama 36362 Re: ADEM Review and Comment: 2022 Annual Long-Term Groundwater Monitoring and Corrective Measures Effectiveness Report for Area of Concern (AOC)-S and Solid Waste Management Units (SWMUs) 2d/AOC-F, 4, 10115, and 14, Fort Novosel, dated August 17,2023 Fort Novosel,Dale County,Alabama EPA ID No: AL6 210 020 776 Dear Mrs. Majors: The Alabama Department of Environmental Management(ADEM or the Department)has completed the review of the subject document. Based on this review, the Department has provided comments in the attached document. The Department's comments should be addressed as part of the forthcoming 2023 Annual Groundwater Monitoring Report. If you have any questions or concerns regarding this matter,please contact Mr. Colin Mitchell of the Governmental Hazardous Waste Branch at 334-271-7967 or at cjmitchell@adem.alabama.gov. Sincerely, a26- - Ashley T. Mastin, Chief Governmental Hazardous Waste Branch Land Division ATM/JBR/CJM/mlw Attachment cc/via email: Jennifer Dennis, USACE Deb Jones, ECC Mark Sherrill, Jacobs Melissa Shirley,USACE Algeana Stevenson, US AEC Lee Thomas,ADEM Allen Thompson,Fort Novosel Birmin9M1amil..0 OtteNrf ll[b Mobile Bonin Modk{oazM Ilowiwn lbea 27155eMIn Red&&.. 22hiharrerer Fawl 4171 Qo aMe,s BLmingNm AL352W4702 ce WCAL35W(11333 I MWIq AL335151131 MUL4k.P13E61S1@I 1205)942d1 125Q13 1713 (251)450-4 MI 432d 33 (205)941-1603 F,4 250) 93590W (25114M2599(Fa0 R51)432b alff J Mrs.Julie Majors December 29,2023 Page 2 of 3 ATTACHMENT ADEM Review Comments 2022 Annual Long-Term Groundwater Monitoring Report for AOC-S and SWMUs 2d/AOC-P,4, 10/15, and 14 Fort Novosel General Comments 1) As stated in Section 1.3,the method detection limits(MDLs)for 1,2,3-trichloropropane, acrylonitrile, and trans-1,4-dichloro-2-butene exceed their respective groundwater protection standards(GWPS) for groundwater samples collected from several SWMUs and AOCs. (The Department notes that ADEM Admin. Code r. 335-14-5 Appendix IX lists 1,4-dichloro- 2-butene and trans-1,4-dichloro-2-butene interchangeably.) In a comment letter dated March 15, 2018,ADEM stated that elevated MDLs would be acceptable for these three constituents. Please continue to evaluate the feasibility of achieving acceptable MDLs for all groundwater sampling constituents on an annual basis. 2) The Department notes that the two semi-annual sampling events occurred within two months of each other. Typically, sampling events at Fort Novosel occur about six months apart. In the future,please ensure that these sampling events are performed far enough apart that seasonal changes in groundwater can be observed. The Department notes that Fort Novosel encountered delays in the sampling event due to contracting issues and anticipates being able to perform future sampling events at the recommended interval. SWMU/AOC Specific Comments SWMU 2d 1) The groundwater flow direction is described in the text and depicted on Figures 3-3 and 3-6 as south-southeast,but the topographic setting of the landfill likely dictates more pronounced easterly and westerly groundwater flow components,which the well network does not address. The Department requests that Fort Novosel continue to analyze the easterly and westerly groundwater flow at SWMU 2d to determine whether the current groundwater monitoring program addresses this flow direction. 2) Metbylene chloride, 1,1-dichloroethane (1,1-DCA), trichloroethylene(TCE), and cobalt exceed their respective maximum contaminant levels (MCLs). Due to elevated concentrations of 1,1-DCA,methylene chloride, and TCE at MW-2A,the inclusion of additional monitoring wells located hydraulically downgradient of MW-2A (e.g.,MW-9) may be necessary. Also,additional wells (located hydraulically downgradient)may be needed to address elevated concentrations of cobalt in groundwater. Please address. SWMU4 3) Cis-1,2-dichloroethane (Cis-1,2-DCE) and vinyl chloride exceeded their GWPSs in two wells. Also, cobalt exceeded its GWPS in 8 of the 11 wells sampled during both sampling events. The Department notes that Fort Novosel is currently developing a revised Corrective Measures Implementation Plan(CMIP) for SWMU 4 to address these GWPS exceedances. Mrs.Julie Majors December 29,2023 Page 3 of 3 SWMU 10/15 4) Benzene, cis-1,2-DCE TCE and vinyl chloride exceeded their respective GWPSs in several wells. The Department notes that Fort Novosel has submitted a revised CMIP that addresses the GWPS exceedances at SWMU 10/15. This CMIP is currently being reviewed by ADEM. SWMU 14 5) Cobalt exceeded its GWPS in well 14-G9. Also,naphthalene was detected in well 14-G4 but did not exceed its GWPS. Please continue to monitor the GWPS exceedance to ensure that the concentrations are trending downward. AOC-P 6) Methylene chloride and 1,1-dichloroethane exceeded their respective GWPSs during this monitoring event in MW-2A only. Also, cobalt exceeded its GWPS in 2 of the 4 monitoring wells (MW-2A and MW-8A). Please continue to monitor these exceedances to ensure that the concentrations are trending downward. As this site is encompassed by the well network associated with SWMU 2d,please see the Department's comments regarding SWMU 2d above. AOC-S 7) Tetrachloroethylene(PCE) was the only volatile organic compound(VOC) that exceeded its GWPS at this site. As stated in the extension request approval letter dated February 9,2023, the Department notes that Fort Novosel plans to submit a revised CMIP by September 30, 2024. This revised CMIP will address the GWPS exceedance at AOC-S.