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A=COM storage areas and other places on Site where foams were/may have been released(e.g., the truck rack and AS Ts in the West Terminal and the railcar offloading rack in the East Annex). Response: Stormwater sampling locations have been added for the West Terminal and East Annex. West Terminal stormwater samples will be collected from control points at the northwest and southwest entry gates (Figure 3). Stormwater samples will be collected prior to discharge. A stormwater sample will be collected at the East Annex from the lined stormwater secondary containment area (Figure 4). The containment is discharged via piping west to Stork Road and then north to West Washington Street. The sample will be collected during discharge prior to leaving the site. Comment 6:Appendix A, Section 1 of the Work Plan provides reporting limits (RLs) but not method detection limits (MDLs) for the PFAS analytes. Additionally, the Work Plan provides no RLs or MDLs for the general chemistry and metal analytes listed in Table 4.1 of Appendix A. Please add those missing items to the Work Plan. For the general chemistry and metal analytes, please include justifications for the proposed RLs (e.g., historical or current analyte concentrations at or near the Site). Response: Attached Table 1 provides the MDLs for PFAS analytes. The RLs and MDLs for general chemistry and metal analytes are provided in Table 2, attached to this response. These RLs and MDLs were provided by Eurofins Sacramento, which is the analytical laboratory that will be utilized for the PFAS analysis. The RLs are determined according to Section 6.6 of the Eurofins SOP NDSC-QA- SOP42091. The SOP is included as Attachment B. Comment 7: Appendix A of the Work Plan does not state whether the field parameters listed in Table 2 of Attachment 2 to the Order will be collected for groundwater samples. Please revise the Work Plan to include measurement of those parameters during groundwater sampling activities. Response: As required by Order WQ 2021-0006-DWQ (California Water Boards, 2021), field parameters will include depth to water, temperature, electrical conductivity, pH, and turbidity collected during groundwater sampling. No other field screening, confirmation, or split samples will be required for this sampling. Comment 8:Appendix A, Section 9 of the Work Plan indicates field blanks will be collected at 1 per 20 samples per matrix or one per week per matrix. The Central Valley Water Board staff strongly recommend that Tesoro Logistics revise the frequency to 1 per 20 samples per matrix or 1 per day, whichever is greater, to evaluate the effects of potential environmental sources of cross-contamination (e.g., wind patterns) on a daily basis. Response: As requested by CVRWQCB field blanks will be collected at a rate of one per 20 field samples, or one field blank per day, whichever is greater, for the full analytical suite. Comment 9:Appendix A, Section 9 of the Work Plan indicates equipment rinsates will be collected at 1 per 20 samples or one per week. The Central Valley Water Board staff strongly recommend that Tesoro Logistics revise the frequency to 1 per day per type of non-dedicated equipment to ensure all kinds of non-dedicated equipment used during the investigation are evaluated for potential cross- contamination. Response: As requested by CVRWQCB equipment blanks will be collected at a rate of one per day per type of non-dedicated equipment for the full analytical suite. Comment 10: The Work Plan does not include the Perjury Statement required by Section V. of the Order. Please include the Perjury Statement signed by a duly authorized representative. Response: In response to Comment 10, the Perjury Statement is included below. The submitted statement applies to the PFAS Work Plan submitted August 31, 2021 and to the responses included in this letter. aecom.com 3/5