AR No. IR No. EIELSON AFB ALASKA. Administrative Record Cover Sheet NOTES:

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1 AR No. IR No. EIELSON AFB ALASKA NOTES: Administrative Record Cover Sheet

2 UNITED STATES ENVIRONMSNTAL PROTECTION AGENCY REGION Sixth Avenue, Suite 900 Seattle, WA ~ OFFICE OF ENVIRONMENTAL CLEANUP May 2:,2012 David E. Beistel 354 CES/CEAN 2310 Central Ave Ste I 00 Eielson AFB AK Re: EPA comment evaluation of comment responses for the: Draft Final Version 2 Quality Assurance Project Plans for Source Areas ST20 and SS35 Dear Mr. Beistel: The Region 10 Environmental Protection Agency (EPA) has reviewed the Draft Final Version 2 UFP-QAPP(s) for source areas ST20 and SS35. Please find attached specific comments and tables that detail and identify UFP-QAPP sections, areas or specific work sheets that need to be further addressed, clarified or revised prior to the finalization of the documents and the start of field work this season. The site-specific UFP QAPPs are in being prepared in conjunction with the installation-wide Generic UFP-QAPP. In combination these documents will comprise the C(l)mplete Uniform Federal Policy Quality Assurance Program Plan for ST20 and SS35. The Generic UFP-QAPP is still in the review process and has not yet been approved. EPA wants to thank you, your colleagues, and the Alaska DEC for the ongoing collaborative effort we have continued to utilize during the proaess of developing these documents. EPA looks forward to working with USAF and the Alaska DEC to resolve the remaining issues, approve, and finalize these documents so that we may begirt the necessary fieldwork for these sites as soon as possible. Aaron Lambert Office of Environmental C leanup D<lVC Beistcl Page I 0 Printed on Recycled Paper

3 cc via Deb Yamamoto, EPA John Halverson, ADEC Robert Shirley, USAF Page 2

4 Technical Review of the Response to EPA s Comments on the Draft Final Quality Assurance Project Plan, Conceptual Site Model Update, Source Area ST20, Eielson Air Force Base, Alaska The following additional comments were generated based on a review of the bulleted points describing information added or altered in the QAPP. Please note the Worksheet #21 was added and lists the standard operating procedures (SOPs) provided in Appendix A to be used for the investigation. However, Appendix A was not provided with the responses to comments, and the SOPs could not be verified. ADDITIONAL GENERAL COMMENTS REGARDING BULLET POINTS 1. The revised QAPP removed the quality control (QC) samples for the field screening of groundwater samples collected for plume delineation, but the collection of QC samples is necessary to ensure accurate decisions (e.g., selection of location of permanent wells) can be based on the resulting data. The collection of field QC samples (e.g., field duplicates and blanks) reduces the potential for missing part of the plume or overestimating plume size, which could necessitate another groundwater sampling event after the off-site laboratory results are received. Please revise the QAPP to include the collection of field QC samples for the groundwater screening samples. 2. The discussion in Worksheet #15, pages 15-1 to 15-2, indicates that the final evaluation of site data will use the lower of the applicable EPA or ADEC criteria for soil, groundwater, indoor air and sub-slab/soil gas, and sediment samples; however, neither Table 15-5 nor the text of Worksheet #15 indicate that the surface water samples will be compared to EPA screening criteria. Please revise Worksheet #15 to ensure that the most conservative EPA or ADEC criteria for surface water will be used for data evaluation. 3. The personnel information in Worksheets # 3, #4, and #5 is insufficient and inconsistent. Worksheet #4 does not include the regulatory personnel or the subcontractors identified on Worksheet #5 (i.e., TestAmerica and GeoTek). GeoTek is also not included in Worksheet #3, and it is unclear what role GeoTek will perform for this investigation. In addition, Worksheet #14 identifies a field laboratory subcontractor as Triad, but this subcontractor is not included in Worksheets # 3, #4, and #5. Please

5 revise these worksheets to consistently present all personnel and subcontractors identified in the QAPP. In addition, please clarify the role of GeoTek for this project. 4. Table 15-6, Evaluation Approach for Compounds for which Project Action Limits Exceed Various Laboratory Limits, identifies several pesticide detection limits (DLs) as exceeding the criteria for protection of benthic invertebrates (e.g., for alpha-chlordane, gamma-chlordane, 4,4-DDD, etc.), but these DLs exceed the human health sediment bioaccumulation screening levels as defined in Table 15-4, not the criteria for benthic invertebrates. Please revise the QAPP to resolve these discrepancies. 5. Naphthalene is identified as an analyte for which the DL exceeds the PAL for indoor air in Table 15-6, but it is not included in the TO-15 SIM analysis because it exceeds the residential screening criteria and not the industrial screening criteria. However, naphthalene has been detected in soil and groundwater, so it is unclear why it should be excluded from screening to the PAL (the residential level) as is proposed for all analytes, even if land use is industrial. Please revise the QAPP to include naphthalene in the TO-15 SIM analysis or provide further justification for its exclusion from screening to the PAL. RESPONSE TO COMMENTS Comment Page Comment/Recommendation Response Evaluation Evaluation of the Response to Comment 3: The response partially addresses the comment. The response indicates that the EA Chemist Text indicating that the EA Chemist performing data validation will be independent of data collection and analysis activities has been included in the Data 1. - analysis activities, but this text has not been incorporated into the QAPP. Please revise the QAPP to ensure this text is included. performing data validation will be Review Tasks portion of Worksheet#14, independent of data collection and page Evaluation of the Response to Comment 5: a. The response addresses the comment; however, no revised text regarding the monitoring well network and current a. Worksheet #9 only contains information regarding stakeholders meetings on future activities relative to the investigation at ST20. Existing and decommissioned monitoring The response partially addresses the comment. Figure 10-2, only shows five of the six monitoring wells mentioned in the response. The missing well appears to be 20PS58, which is cited in the text, but is not depicted on any of the figures. Please

6 groundwater monitoring could be located in either Worksheet #9 or Worksheet #10. Please ensure the QAPP has been revised to include the discussion of the monitoring well network and current groundwater monitoring. b. Where in the referenced guidance does it indicate that the EA personnel will be independent of collection and analysis activities? wells (color-coded to be distinguished from each other) at ST20 are depicted on Figures 10-2 through To the extent that samples from these wells were collected as part of monitoring activities is discussed in Worksheet #10, Tables 10-3 through The current monitoring well network at source area ST20 consists of six monitoring wells; these wells are included in the CSM investigation and are discussed in Worksheet #14, page 14-1 through 14-6, and Worksheet #17, page 17-1, and identified in Tables 10-3 through 10-11, 11-1 and 11-2 and Figures 11-1, 11-2, and Additional monitoring wells will be installed in strategic locations based on field screening data, as outlined in Worksheet t #11, pages 11-2 and 11-3, Worksheet #14, pages and 14-18, and Worksheet #17, page 17-4, to complete the monitoring well network. As outlined in the decision process for this project, the actual location of the new monitoring wells to be installed will be decided, collaboratively, by all stakeholders, based on screening-level data. revise the figures to show all six of the ST20 monitoring wells. In addition, there are no wells located in the vicinity of the E-8 plume, and it is unclear how the extent of this plume has been evaluated without a sufficient well network. It is understood that a well is planned for installation at the E-8 plume, but it is not understood why the wells in this area were decommissioned in the first place. Please ensure that an adequate monitoring well network is established to evaluate the extent of the E-8 plume. b. See response to comment 1 (initial comment 3). Plume stability is not part of the scope of this QAPP and has been removed. The text in the introduction to the QAPP, page 1, has been revised to state This investigation is being performed to close data gaps in the current CSM. Results will be used to select future remedial actions that are in 3. 1 Evaluation of the Response to Comment 6: The response partially addresses the comment. The response agrees that the stability question can only be determined by LTM, and as such LTM will be discussed and decided with the regulating agencies following receipt The response addresses the comment; however, the term LTM still appears in many locations in Worksheets #10 and #14 and may be confusing to users of this QAPP. For the bullets in the data gap sections, it may be better to use the phrase future LTM, in place of LTM. Please

7 of data from this sampling event; however, it is not clear why the concept of plume stability has been included in the QAPP if it cannot be investigated until after the field work is complete. Please justify why the concept of plume stability has been included in the QAPP when the current proposed field work is not applicable. Please exclude the discussion of plume stability until later investigations are completed. compliance with USAF s 2010 accelerated site completion directive with the ultimate goal of achieving site closure under both State and Federal Regulations. Introduction, page 1. consider replacing LTM with the phrase future LTM for clarity Evaluation of the Response to Comment 8: The response partially addresses the comment; however, the response does not indicate the minimum number of results needed to support the risk assessment, nor does the response indicate whether the proposed sampling meets this minimum. Please revise the response to address this outstanding issue A risk assessment will not be performed as part of the CSM update. References to risk assessment were removed from the document. Worksheet #11, page 11-4, and Worksheet #15, page Evaluation of the Response to Comment 12: The response partially addresses the comment. The response did not address the request for revision of the grids to extend at least one perimeter ring beyond the current understanding of benzene contamination. In addition, the text of the QAPP still states that up to 30 locations will be sampled at each site. It is not clear why this statement still remains when the Triad is intended to determine the number of sample locations needed for each site. Please revise the grids as The grid has been modified as shown on Figures 11-1, 11-2, and Note that no borings are allowed by the USAF through the paved areas of the taxiways and aprons. Of note is that the grids as shown on these figures are not in any way limited for expansion, with the exception of the areas covered by concrete or pavement. The criteria for achieving delineation is outlined in Worksheet 14, page 14-8 through The investigation will advance until these criteria are met. Worksheet 14, page 14-8 and 14-12, Table 11-1, and Worksheet 17 Page 17-2.

8 requested in the original comment. Please also consider removing the limitation of 30 sampling locations so the Triad will not be limited if a site requires more sampling locations. The limitation of 30 boring locations has been removed as shown in Worksheet 17, page 17-2, item 2b Evaluation of the Response to Comment 22: The response addresses the comment; however, it is recommended that revised figures be included in this QAPP to ensure this agreed change will be carried over to future documents. Please include the revised figures for Worksheet #10 in the QAPP. Kwasi Boateng s phone number is incorrect. (206) is the correct phone number ST20 consists of three complexes: E-7, E-8, and E-9. The approximate Historical Source Area Boundary (USAF 1994d) for each complex is now shown on all applicable figures (10-2 through 10-10, and 11-1 through 11-3) Mr. Boateng s phone number has been corrected in Worksheet #9, page 9-1.

9 Technical Review of the Response to EPA s Comments on the Draft Quality Assurance Project Plan, Conceptual Site Model Update, Source Area SS35, Eielson Air Force Base, Alaska The following additional comment was generated based on a review of the bulleted points describing information added or altered in the QAPP. ADDITIONAL GENERAL COMMENTS REGARDING BULLET POINTS 1. While it is understood that a new goal has been added to compare sediment data to ecological screening criteria, it is unclear how the extent of contamination in the water treatment pond will be defined. For example, the use of randomly selected sampling locations in the interior of the pond does not define how the extent of contamination will be determined if the samples along the northern and western edges exceed criteria (e.g., samples from grid locations D-34 and H-37). In addition, it is unclear why the collection of 22 sediment samples was deemed sufficient for evaluating ecological criteria. Please revise the QAPP to provide greater detail on the rationale for reducing sediment samples to 22 locations and ensure this addresses how the extent of contamination will be determined.

10 RESPONSE TO COMMENTS Comment Page Worksheet Comment/Recommendation EA Response Evaluation GENERAL COMMENTS 1. General - The Draft Quality Assurance Project Plan, Conceptual Site Model Update, Source Area SS35 (the QAPP) states the updated conceptual site model (CSM) will be used to provide a clear path forward regarding the protectiveness of future remediation and/or monitoring efforts, but does not specify how the updated CSM will be used for this purpose nor how the updated CSM will impact the remedy selected in the Record of Decision (ROD), if at all. Further, a discussion regarding how the data will be used to select new well locations for long-term monitoring (LTM) should be discussed in the QAPP. Please clarify how the proposed sampling activities fit into the CERCLA process and support the 1995 ROD and what longterm monitoring will be implemented. 2. General - The QAPP uses the term TBD [to be determined] in several locations. Any information that is currently TBD in the QAPP should be resolved prior to the submittal of the next version of the QAPP. Please ensure the QAPP is updated to replace all TDB entries with the appropriate information. A brief description of where we are and where we are going has been provided in the document Introduction, as agreed to during review of comments on ST48. Text provided by the reviewing agencies was added. Introduction: Page 1, redlined page 1 LTM discussion has been deferred to the IWMP report. Introduction: Page 1, redlined page 1 TBDs in Table 11-1 from Worksheet #11 have been replaced with the appropriate information. Table 11-1 The response partially addresses the comment. Page 1 on the SS35 QAPP states the requirements of the Record of Decision (ROD) for this source area to perform long-term monitoring (LTM) are not addressed in this Quality Assurance Project Plan (QAPP), rather in the Installation- Wide Monitoring Program QAPP; however, the IWMP QAPP states this QAPP covers the reinstatement of activities to address the long-term monitoring (LTM) requirements from the RODs and ROD Reviews, but addresses only field activities to be performed in 2012 under the IWMP. This means that only 2012 sampling is addressed, and any additional LTM discussion is outstanding. Please ensure that the SS35 QAPP clearly states that the IWMP QAPP only addresses the 2012 sampling, and that additional LTM activities have yet to be established.

11 Comment Page Worksheet Comment/Recommendation EA Response Evaluation 3. General - The QAPP discusses real-time measurements and the Triad approach in several worksheets. However, it is not clear what real-time measurements will be collected and how the Triad approach will be used at SS35. Further, the text on the bottom of page 11-3 states that not all sampling locations could be depicted on Figure Therefore, it is not clear whether all proposed sampling locations will be sampled (e.g., 132 sediment samples), or if only a portion of them will be sampled. If only a portion of the proposed samples are collected, then the criteria used to select the final locations should be summarized. If the Triad approach will be used to make real-time decisions about sampling locations, some sort of criteria should be used to guide the Triad s decisions, and these criteria should be presented in the QAPP. Please revise the QAPP to describe the real-time measurements that will be collected and how Triad will be used. Please also indicate whether all 132 of the proposed sediment sample locations displayed on Figure 11-1 will be sampled. 4. General - The rationale for selecting the matrices and associated suites of analytes is not sufficiently described in the QAPP. Further, it is unclear how remediation goals for the QAPP were determined. Examples of deficiencies that need to be addressed include: a. Surface and subsurface soil are indicated as complete pathways in the Conceptual Site Model, but no soil samples are The Triad approach is not being used for the CSM update at SS35. References to the Triad approach have been removed. Introduction: Pages 2, 3 (redlined pages 2, 4) WS #11: Page 11-5, redlined page 11-5 Sediment sampling is discussed in Worksheet #11, pages 11-3 and 11-6 (redlined pages 11-3 and 11-7), Table 11-1, Figure 11-1, and Worksheet #14, pages 14-1, 14-8, and 14-9 (redlined pages 14-1, 14-11, and 14-12). a. During the scoping meetings, it was decided that geophysical surveys should be conducted to determine extent of buried debris, and the potential need for removals prior to conducting soil sampling. b. Project actions limits for sediment are now provided in WS #15. (see pages 15-1 and 15-2, redlined pages 15-1 through 15-3; Table 15-3). Project action limits for other media a. The response is partially adequate. Surface soil samples are proposed to be collected along the water treatment pond to identify contaminants that could wash into the pond; however, it does not appear that subsurface sampling has been added. It is unclear why subsurface soil contamination does not need to be updated or

12 Comment Page Worksheet Comment/Recommendation EA Response Evaluation proposed. b. Sediment samples are proposed, but no remediation goals are listed in Table c. It is unclear why pesticide analysis only is proposed for sediment samples and not all contaminants of concern listed in Table d. It is unclear if and how the action levels in Figures 10-3 and 10-4 relate to the remediation goals in Table 10-1 e. It is unclear how the remediation goals in Table 10-1 were established (i.e., by the record of decision). f. Usage of the term Maximum Contaminant Level (MCL) on Figures 10-3 and 10-4 is misleading. The MCL is specific to drinking water standards established by the EPA and do not apply to sediment or surface water results. Please revise the QAPP to justify the target matrices and analytes and better describe the remediation goals for this project and how they were determined. are also provided in WS #15. c. A more thorough discussion of contaminants is presented in WS #10 to describe the selection of analytes by media. (see pages 10-2 through 10-7, redlined pages 10-3 through 10-14; Tables 10-1 through 10-13) d. The figures have been revised, and no longer reference action levels. e. The Table was incorrect and has been deleted. (Worksheet #10, redlined page 10-8) f. The reference to MCL has been deleted. assessed. Please revise the QAPP to discuss why subsurface soil does not require analysis for this CSM update. b. The response is partially adequate, however further clarification is necessary. The footnotes for Tables 15-1 and 15-3 indicate that the final evaluation of site data will use the lower of the applicable EPA or ADEC criteria for soil and sediment samples, but Tables 15-2 and 15-4 do not indicate that EPA criteria will be used for this comparison. Worksheet #15 should indicate if ADEC screening criteria are at least as protective as the EPA screening criteria (e.g., EPA RSLs for soil, groundwater, and National Recommended Water Quality Criteria for surface water) or the tables in Worksheet #15 should clarify that the most conservative criteria will be used. Please revise Worksheet #15 to address these issues. c. The response is not adequate. The QAPP does not discuss the rationale for the different analytes proposed for sediment samples. It is unclear why the 13 sediment samples to be collected from the pond outlet and pond interior will be

13 Comment Page Worksheet Comment/Recommendation EA Response Evaluation SPECIFIC COMMENTS Table 11-1 shows 0 in the columns for analytical suites for equipment blanks during baseline groundwater sampling and groundwater sampling post plume delineation. The table does not specify whether dedicated sampling equipment will be used and the text states dedicated and/or disposable sampling equipment will be used to the degree possible. If dedicated sampling equipment is not used, then equipment blanks should be collected. Please revise Table 11-1 to clarify whether dedicated sampling equipment will be used, and if not then equipment blanks should be added. Table 11-1 has been revised to indicate that disposable sampling equipment will be used for groundwater and surface water sampling. analyzed for pesticides and PCBs only, while the rest of the 9 samples to be collected from the pond inlet and along the shoreline will be analyzed for a larger suite of analytes. Please revise the QAPP to discuss the rationale for the selection of different analytes for sediment samples.

14 Comment Page Worksheet Comment/Recommendation EA Response Evaluation Worksheet #14 discusses the electromagnetic survey to be performed at SS35, but does not outline details of the survey transects, such as how many transects will be completed, in what direction will the transects lie, how long will the transects be and how far apart will they be spaced, etc. Please revise Worksheet #14 to provide additional details about the electromagnetic survey to be performed at SS , 15-5 and Tables 15-1, 15-2, and 15-3 contain practical quantitation limits (PQLs) that are higher than the project action limits (PALs). Please discuss how a PQL value that is higher than the PAL value impacts the quality and usability of the data for these analytes Worksheet #17 states the existing wells will be gauged for use in determining the direction of groundwater flow at the site; however, it is not clear why the direction of groundwater flow was not determined in the past using existing groundwater data. Please explain why the existing groundwater data is not sufficient to determine the direction of groundwater flow and explain why the flow direction was not determined during past investigations at SS35. Additional detail on the surveys is provided, including the distance between transects, and Figure 11-1 shows the area to be surveyed, however, the number of transects is not provided because it will be up to the surveyor to determine direction of transit based on condition such that they obtain the best results possible. (WS #14, page 14-3, redlined pages 14-4/14-5) SOPs for the EM and GPR surveys has been provided in Appendix L. The text has been revised and a table has been added to discuss this issue similar to what was prepared for ST-48. WS#15 page 15-2, redlined page New Table Text has been revised as follows: New and existing wells will be gauged to evaluate the direction of groundwater flow; two gauging events will be performed because of anticipated seasonal variations in the groundwater flow direction. WS #17, page 17-2, redlined page The response addresses the comment; however, it is not clear why Worksheet #14 describes the usage of a raft for portions of the geophysical survey that are over the pond, because Figure 11-1 appears to exclude the pond from the geophysical surveys based upon the study area boundaries. In addition, if a raft will be used to complete transects over the pond, the raft must be non-metallic, which should be specified in the text. Lastly, Worksheet #14 is not consistent with Worksheet #17, because Worksheet #17 states that the survey will only extend to the shoreline of the pond. Please resolve these issues. The response does not address the comment. The revised text does not indicate why groundwater flow direction could not be determined in the past, nor does it discuss how new data will help determine the flow direction, particularly since the wells are roughly located along a straight line. Triangulation to determine groundwater flow direction may not be accurate without at least one well located near Central Avenue or west of the pond. Please revise the revised text to address these issues.

15 Comment Page Worksheet Comment/Recommendation EA Response Evaluation The last section of Worksheet #17 indicates that to reduce redundancy, only general information on how decisions are to be made regarding these elements is presented in this worksheet; however, Worksheet #17 does not provide any information beyond the references to portions of Worksheet #11. Please revise the last section of Worksheet #17 to include general information regarding how sampling decisions have been or will be made. Text has been revised as follows: With the exception of locations of new monitoring wells and the provision for additional surface soil samples, the investigation at SS35 will be conducted at pre-selected sampling locations to meet the goals identified in Worksheet #10. Once data from this investigation are available, stakeholders will provide input in the decision making process in determining what future efforts will be needed to guide the investigation toward a common goal protection of human health and the environment. WS #17, pages 17-3 and 17-4, redlined page 17-5

16 Comment Page Worksheet Comment/Recommendation EA Response Evaluation MINOR COMME NTS Page 10-3 discusses the three anomalies found during the Remedial Investigation (RI) geophysical survey, but does not indicate what is thought to be the cause of anomaly Area A. The suspected cause of the anomalies at Areas B and C are provided, so it is unclear why similar information has not been included for Area A. Please revise Worksheet #10 to discuss the suspected cause of the geophysical anomaly at Area A. The entire site background has been revised. It should now be clear that the anomalies arise from past practices at the site and could be buried drums. However, since these anomalies were not excavated, the exact nature of the anomaly is not known. (WS#10, pages 10-3 through 10-5, redlined pages 10-4 through 10-11, Table 10-1) , 10-6, and Page 10-6 indicates that no samples were collected in 2000 and 2001 and page 10-7 states that no sampling was conducted in 2005, 2006, and 2007, but page 10-5 states that annual monitoring has been conducted since Please briefly explain why no monitoring samples were collected in 2000, 2001, 2005, 2006, and From 1998 to 2003 sampling was conducted in accordance with an approved schedule based on the 1999 work plan. After 2003, sampling was conducted as directed by Remedial Project Managers. See rewritten sections in WS #10, pages 10-2 through 10-5, redlined pages 10-3 through 10-11; Table 10-1.