Department of Toxic Substances Control Barbara A. Lee, Director Matthew Rodriquez 8800 Cal Center Drive Edmund G. Brown Jr. Sacramento, California 95826-3200 6mm? August 23, 2016 Mr. Michael Bower The Boeing Company 5800 Woolsey Canyon Road MC Canoga Park, California 91304?1148 DEPARTMENT OF TOXIC SUBSTANCES CONTROL COMMENTS ON THE BOEING DRAFT RCRA FACILITY INVESTIGATION DATA SUMMARY AND FINDINGS REPORTS FOR SUBAREA 5/9 SOUTH, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA Dear Mr. Bower: The Department of Toxic Substances Control (DTSC) has completed its review of The Boeing Company?s (Boeing) draft RCRA Facility Investigation Data Summary and Findings Reports for Subarea 5/9 South (Subarea 5/9 South Reports) at the Santa Susana Field Laboratory (SSFL). The Subarea 5/9 South RFI Reports include information for the following related sites and areas: Subarea 5/9 South Compound A Environmental Effects Laboratory (EEL) Systems Test Laboratory IV Sewage Treatment Plant 3 (STP-3) Subarea 5/9 South Areas Unaffiliated with RFI sites. The Subarea 519 South RFI Reports were prepared by and are dated June 2015. The reports were reviewed by DTSC staff from DTSC's SSFL project team, Geological Services Unit (GSU), and Human and Ecological Risk Office (HERO). The purpose of RFI reports is to present the nature and extent, and fate and transport of contamination at the study sites. They also identify the current potential health risks to human and ecological receptors in sufficient detail so that cleanup alternatives can be evaluated in the Corrective Measures Study (CMS). However, based on review, the Subarea 519 South RFI Reports will require significant revisions prior to the next submittal because the reports do not adequately present the risk assessment results. Mr. Bower August 23, 2016 Page 2 of 4 While the Subarea 5/9 South RFI Reports require significant revision, the data themselves are sufficient for both the completion of the RFI and evaluation in a CMS. In the event cleanup goals. are established that are lower than the screening levels used to characterize the site, additional characterization may be required, and can be completed during the remedial action phase of the project. Below is a summary of the overarching issues DTSC identified in the Subarea 5/9 South RFI Reports: CMS and No Further Action (NFA) The RF I Reports are not the appropriate document to propose identification of CMS areas, and DTSC does not agree with the NFA recommendations. The Subarea 5/9 South RFI Reports include Boeing?s proposed CMS and NFA areas based on: A suburban residential scenario, and 0 An ecological risk scenario, calculated using the high Risk Based Screening Levels (RBSL). It is inappropriate to imply that cleanup will be based on either of those scenarios in the RFI Reports. Further, the development of the CMS and NFA areas included risk management decisions. DTSC is responsible for making the risk management decisions and, where appropriate, NFA determinations. DTSC makes those decisions in the cleanup decision document. Please remove the CMS and NFA areas from the RFI Reports. Nature and Extent of Impact ?The nature and extent of soil impacts should be presented based on RFI data posted to the appropriate figure(s). Incremental Excess Lifetime Cancer Risks (ELCR) for Soil - Incremental ELCR for human health for chemical and radiological soils were inappropriately calculated by subtracting the background risk from the total site risk by media. In cases where the 95 percent upper confidence limit of the mean (95 UCL) for background is greater than the 95 UCL for the site, the background risk is higher than the site risk from the chemicals and radionuclides of potential concern (COPCs, ROPCs). When this occurred for risk drivers arsenic and other analytes at STL IV), the incremental site risk was reported as or ?no incremental risk over background?. This reporting practice can mask the incremental site risk contributed by other COPCs and ROPCs. The RFI Reports need to present revised incremental risk calculations. Total incremental site risk - Total incremental site risks for human health (is. summation of chemical and radiological carcinogenic risks) were not presented in the Subarea 5/9 South RFI Report. The reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, and include the risks caused by ingesting homegrown fruits and vegetables. Mr. Bower August 23, 2016 Page. 3 of 4 . Human Health Risk Assessment (HHRA) Input Parameters The United States Environmental Protection Agency (US EPA) recently updated input parameters for the produce contaminated fraction (or fraction of produce consumed from a contaminated source), ingestion rates for fruits and vegetables for the both the adult and child, body weight for the adult, residential exposure duration for the adult, and produce plant mass loading factor. The Subarea 59 South risk assessments and further submittals must reflect the most current input parameters. Boeing is to re-evaluate the HHRA input parameters, compare them?with US EPA default values, and submit the proposed revised input parameters to DTSC for review and approval. Hypothetical Suburban Resident with a Garden Exposure Scenario The hypothetical suburban resident with a garden exposure scenario has only been evaluated and reported in Appendix of the site reports (Compound A, EEL, STL-IV, and Similar to the direction given for incremental site risk above, the reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, including intake from ingesting homegrown fruits and vegetables. The results need to be summarized in the main text of the site reports and the subarea report, in the same manner as the hypothetical suburban resident and future recreator exposure scenarios. Ecological - The reports incorrectly assumed that the high could be utilized to develop CMS and NFA areas. Evaluate the utility of the high and low ecological in the uncertainty analysis section of the risk assessment included in Appendix E2 of the site-specific reports, so risk management decisions relating high RBSL can be assessed by DTSC. Attached are DTSC's comments and technical memoranda on the Subarea 5l9 South RFI Reports. The comments and memoranda include: Comments on the report by SSFL Unit staff: 0 Subarea 59 South Compound A EEL STP-3 Subarea 59 South Areas Unaffiliated with RFI sites. 00000 Technical memoranda from HERO: Subarea 5i9 South, - Surface water HHRA . Groundwater HHRA Mr. Bower August 23, 2016 Page 4 of 4 HHRA and Subarea 5/9 South Appendix HHRA for Groundwater Compound A HHRA and Subarea 5/9 South Appendix HHRA for Groundwater, EEL HHRA and Subarea 5/9 South Appendix HHRA for Groundwater, and Ecological risk assessment (overall comments). . Technical memorandum from GSU: Groundwater components of the overall document submittal. The directions for re-evaluating HHRA input parameters and presenting cumulative risk will require an addendum to the SRAM. If you have any questions or would like to schedule a project meeting to discuss comments on either the reports or the addendum to the SRAM please contact Julie Lincoln via email at Julie.Lincoln@dtsc.ca.qov or at (916) 255-3684. Sincerel Rog/er aulson PE Chief SSFL Project Support Unit Department of Toxics Substances Control Attachments: cc: (via email) Mark Zeller The Boeing Company Mark Malinowski Department of Toxic Substances Control Mark.Malinowski@dtsc.ca.gov Julie Lincoln Department of Toxic Substances Control Julie.Lincoln@dtsc.ca.qov Mindy Mathias Department of Toxic Substances Control Mindy.Mathias@dtsc.ca.gov Donald Greenlee Department of Toxic Substances Control Donald.Greenlee@dtsc.ca.qov Brian Faulkner Department of Toxic Substances Control Brian.Faulkner@dtsc.ca.qov Tom Seckington Department of Toxic Substances Control Tom.Seckinqt0n@dtsc.ca.qov Mr. Buck King Department of Toxic Substances Control Buck.King@dtsc.ca.qov DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South Santa Susana Field Laboratory, Ventura County, California No. Section 1 General 2 General 3 General 4 General Page Comment CMS and NFA areas were included in the RFI (reference Figures ES1a, ES1b, and ES1c in the Boeing RFI Subarea 5/9 South DSFR) for the suburban residential scenario and ecological risk for the high RBSL, inappropriately implying cleanup will occur based on these scenarios in the RFI Report. Further, the development of the CMS and NFA areas included risk management decisions that are exclusively made by DTSC. Please remove the CMS and NFA areas from the document. Please complete a thorough editorial review of the documents. In many cased incorrect tables or documents have been referenced in the text, tables, and figures making the review process difficult. A few examples (but not all) of these issues are presented below. • Section 1.3, page 1-6 states the following, “Additional groundwater work plans have been prepared in response to DTSC comments on the 2009 Draft Site‐Wide RI Report for seeps and springs (Pierce et al., 2012), faults (MWH, 2013b, 2014d), and groundwater flow and contaminant transport (Boeing, 2013).” The reference for MWH, 2013b is for the Recommended Approach for Evaluating Vadose Zone Mass Flux of Contaminants to Groundwater. Please verify this is the correct reference given the sentence is discussing faults. • Section 2.1, page 2-2 states the following, “The detailed approach for identifying potential sources of contamination is presented in the DQO Report (CH2M, 2013h) and the Master Data Gap Work Plan (CH2M, 2013a).” The reference for CH2M, 2013h is for the Recommended Approach for Assessing the Vapor Intrusion Pathway. Please verify this is the correct reference given the sentence is discussing the DQO Report. • Section 3.1, page 3-1 states the following, “CMS area identification involved the following step‐ wise, iterative process: (1) including sampling results with the highest concentrations of the RFI site‐specific human health or ecological risk drivers as preliminary CMS areas, with consideration of operational use areas, physical constraints (for example, bedrock), and concentration gradients; (2) recalculating estimated risks/hazards for the RFI site without those results (to simulate site risk following cleanup), to verify if residual risks are below or near DTSC risk threshold values; and (3) iteratively modifying the CMS areas and re‐calculating residual risk until DTSC risk threshold levels are achieved for the RFI site as specified in Appendix C of the DQO Report (CH2M, 2013j).” A reference for CH2M, 2013j is not included in Section 4. Please verify the correct reference and update as appropriate. Please include the information in this document versus just referencing a previous document. At a minimum, include a brief narrative describing the information included in the referenced document. When referencing documents please be sure to make as direct/complete of a reference as possible. Please do not reference a document that references another document which actually contains the information. Also, do not refer to a document that contains the information in an appendix but rather make a direct reference to the appendix. Page 1 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South Santa Susana Field Laboratory, Ventura County, California No. Section 5 Electronic Version of Report 6 ES Last Paragraph ES-2 7 ES Table ES-1 8 ES Table ES-1 9 ES Table ES-1 10 ES Table ES-1 Define ROC in the notes as well as any other acronyms that have not been spelled out. 11 ES Figures ES1a – ES-1d Four figures are used to show the 5/9 South Subarea. Consider presenting the entire subarea on one larger figure. Sections 3.4.12 and 3.4.13 of the 2007 Consent Order require the preparation of a SSFL-wide groundwater RFI report not information for a SSFL-wide groundwater report. Consider modifying template language for accuracy. Verify whether Figure 1-1 should also show the groups from the 2007 consent order (particularly Groups 5 and 9). It shows the boundaries of the groups but does not include labels. 12 13 1.1 First Full Paragraph 1.2 Paragraph 1 Page 1-2 1-3 Comment The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. The last paragraph discusses a CMS for groundwater. However, discussion of the Site-Wide Groundwater RFI report is been omitted. Please include a discussion of this report as you have included discussion of other reports affiliated with 5/9 South that have not yet been submitted. Please summarize all risks in this table. At a minimum, the following information needs to be added to the table: Hypothetical Suburban Resident with a Garden exposure scenario, adding radiological risks to the human health exposure scenarios (where applicable), and information for the low EcoRBSL. This table inappropriately reports incremental excess lifetime cancer risk (ELCR) as “NR” which according to the notes is “No incremental risk above background”. Please reassess incremental ELCR and report it correctly in this table. The notes in the table defines “IELCR = incremental excess lifetime cancer risk” but the table itself uses “incremental ELCR”. Please rectify this. 14 1.2 Paragraph 3 1-3 Typo: In the first sentence the EEL site is mentioned, but the other RFI sites are not. 15 1.2 Paragraph 3 1-3 “…applying the SSFL comprehensive DQOs to the Boeing RFI subareas and for completing the RFI.” Please refer to comment #19 from the 60% template document and modify this sentence as proposed in the RTC. Page 2 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment The fourth paragraph under Section 1.2 states that the 5/9 South DSFR builds on “the information presented in the draft RFI reports for Groups 5 and 9…” and relevant documents are listed in Section 1.3. If memory serves, DSFRs would clearly state that the original RFI reports are to be incorporated by reference. If so, then such a statement needs to be added; especially since “the 5/9S DSFR will serve as the Final RFI report for Boeing RFI Subarea 5/9 South.” We should discuss whether such a statement needs to be included in each of the site-specific DSFRs or whether doing so in the “overview” alone is sufficient. 16 1.2; 1.3 1-3 to 1-6 17 1.2 Paragraph 4 1-3 18 Section 1.3 1-5 19 1.3 1-5 20 2 2-1 21 2.1.1.1 Paragraph 1 2-2 22 2.2.1 2-3 23 2.2.2.4 2-5 24 2.2.2.6 2-6 Verify whether the Group 9 report reference should single out the Silvernale RFI site. Please mention the Site-Wide Groundwater RFI report in the last bullet in this section discussing Groundwater. A “SSFL-wide groundwater report” is mentioned in Section 1.1 and should be included in Section 1.3 as well. Verify when the listed Vapor Intrusion Evaluation Summary Technical Memorandum will be submitted to DTSC and whether it will present the details and evaluation of the additional VI investigation activities proposed in the 5/9 South VI TM (February 2015). In addition, verify whether the 5/9 South VI TM should be referenced here. The last paragraph on the page states that “information was also presented to public stakeholders during quarterly meetings.” However, not all such meetings were quarterly; a later arrangement. The statement should be revised to read simply that the information was presented during periodic meetings, or something similar. “Recommendations to address data gaps identified after review of the Sanitary Sewer System TM were incorporated into site-specific addenda to the Master RFI Data Gap WP for RFI sites in Boeing RFI Subarea 5/9 South.” The sewer system TM was published in 2015, and the data gap addenda for 5/9 South were all completed in 2013 and 2014. Please modify the text for accuracy. The additional data provided by DOE and NASA after preparation of the DSFR should be incorporated with the rest of the site data for the final versions of the reports. The statement that “Additional data were collected by DOE and NASA and provided to Boeing after preparation of the DSFR for each RFI site had commenced” should be removed from the final version of the report. A figure should be included to show the locations of wells RS-37, RS-38, RS-40, and RS-41 mentioned in the text of the report. The last paragraph on this page introduces, and uses for the only time, the concept of the garden scenario. Therefore, considering that this is the overview document, it would seem appropriate to place this concept in proper context, including that examining this scenario is in compliance with the SRAM to be evaluated separately. Page 3 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment 25 2.2.2.6 Last Paragraph 2-7 A reference to a figure showing the location for HAR-18 should be included. 26 2.2.2.6 First Bullet 2-8 Potential typo in the second sentence: “This chemicals that…” should read “The chemicals that…” 27 2.2.2.6 2-8 A figure should be included to show the locations of FDP-881, FDP-890, and FDP890Pool. 28 4 4-2 “Draft” should be removed for the Sanitary Sewer Assessment. 29 5 5-1 Groundwater should also be included in the definition of characterization level. 30 Appendix A 3.7 3-6 31 Appendix A Attachments 1 and 2 32 Appendix A Attachment 1 33 Appendix B Table 1 34 Appendix B Figures 35 Appendix B Figure 9 36 Appendix B Figure 20b 37 Appendix C Table C-1 Please add a description for note “a.” 38 Appendix C Table C-2 Please add a description for note “a”. Explain the impact of the rejection of 8 results, and verify whether additional sampling (or resampling) is needed. These sections state that the data summary reports are provided on cd, but the pdf version of the report does not include these. They were provided separately as many individual files. Please incorporate these as part of the pdf version of the report for completion. The laboratory reports are partial. Please provide the complete Final Laboratory Reports. The diameter for ES-27 is listed as 12 inches in the table, but the well log lists 15 inches. Please verify the diameter. The 5/9 South subarea is shown on Figure 2. It would be helpful to see this boundary on the remaining figures that show the subarea. For example, Figure 13 shows areas to the north and east of the 5/9 South subarea with high soil and soil vapor concentrations but without the 5/9 South subarea boundary looks like it could be associated with an unaffiliated area within 5/9 South. Please provide year labels for the bottom left bar graph. It is confusing to read without them. WS-11 only shows up for a few increments on this figure. Verify whether it is being covered up by WS-9A. If the light-grey lines in this figure’s cross-sections represent the respective ground surfaces (it appears that they do), then please explain why in nearly all of the sections (D-D’ and E-E’ appear to be exceptions) the dots representing “Non-pumping” and “Pumping” “Pathline Intersections” extend above the ground surface(s). Also, the E’ is missing in Figures 20b and 22. Page 4 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South Santa Susana Field Laboratory, Ventura County, California No. Section Page 39 Appendix C Table C-2 40 Appendix C Table C-2 Comment In Table C-2, footnote “a” indicates the following, “Groundwater comparison concentrations developed for use in risk assessments at the SSFL are from Table 3-6 of the SRAM Rev. 2 Addendum (MWH, 2014). The data and methods used to calculate groundwater comparison concentrations are presented in Appendix E of the SRAM Rev. 2 Addendum.” The referenced document does not appear to have a Table 3-6. Additionally Appendix E in this document is called Inhalation Toxicity Reference Value Updates for Use in Ecological Risk Assessments at the Santa Susana Field Laboratory, Ventura County, California – Technical Memorandum. The footnote is incorrect. Please revise this appropriately. Additionally, please include a statement indicating why Groundwater Comparison Concentrations are “not available” for many parameters. I believe the Groundwater Comparison Concentrations are for parameters that may be associated with background concentrations in groundwater. If this is the case, it should be explicitly stated in the text. This means if any parameter is not potentially associated with background and it is detected (using validated laboratory analyses) in excess of concentrations observed in laboratory or field blanks it is considered a COPC and carried through the risk evaluation. Is this correct? Table C-2, a summary of the exposure point concentrations is presented in this table. The text indicates the samples collected over the last 3 years were used to develop the EPCs. Further it indicates when inorganic data were reported for both dissolved and total forms, the highest value was selected as the EPC. Please include a table presenting the data used to develop the EPC concentrations including showing both total and dissolved metals concentrations so the EPC concentrations can be confirmed. Page 5 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. Section • General • General • General • General • General • General Page Comment CMS and NFA areas were included in the report for the suburban residential scenario and ecological risk for the high RBSL, inappropriately implying cleanup will occur based on these scenarios in the RFI Report. Further, the development of the CMS and NFA areas included risk management decisions that are exclusively made by DTSC. Please remove the CMS and NFA areas from the document. Incremental ELCR for human health from soil for chemical and radiological risk was inappropriately calculated by subtracting the background risk from the total Site risk by media. Background risk for some analytes was higher than total site risk for chemicals and radionuclides of potential concern (COPCs, ROPCs) where the 95 percent upper confidence limit (UCL) for background is greater than the 95 percent UCL for the site. When this occurred for risk drivers (e.g., arsenic and other analytes in the 5/9 South STL IV RFI DSFR), the incremental Site risk was reported as “NR” or “no incremental risk over background”. This reporting practice gives the appearance of “masking” the incremental Site risk contributed by other COPCs and ROPCs. In the tables that present total site cancer risk and hazard quotients (HQ), background cancer risk and HQ, and incremental cancer risk and HQ for each COPC, sum the total site risk and HQs and incremental risks and HQs. The summation should be included for each exposure scenario. Where any COPC or ROPC is a “driver” or “major contributor” to the total Site cancer risk or HQ (as defined in Appendix J of the SRAM Revision 2 Addendum), and the background cancer risk or HQ exceeds the total site cancer risk or HQ, then exclude the cancer risk or HQ for the COPC or ROPC from calculation of the incremental ELCR cancer risk and HQ. Evaluate the data for these Site COPCs or ROPCs using the Hot Spot Evaluation method per Appendix J of the SRAM Revision 2 Addendum. Total incremental ELCR risks for human health (i.e., summation of chemical and radiological carcinogenic risks) were not presented in the RFI Report. The reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, including intake from ingesting homegrown fruits and vegetables. The reports incorrectly assumed that the high ecological RBSL could be utilized to develop CMS and NFA areas. Please evaluate the utility of the high and low ecological RBSL in the uncertainty analysis section of the risk assessment included in Appendix E2 so risk management decisions relating to the use of the low or high RBSL can be assessed by DTSC. Please provide documentation of deviations from the proposed samples for step out iterations 2 nd through 4. A table similar to Table C-3 in the 2 Iteration Work Plan would be helpful. Please provide Field Log Books, Boring/Trench Logs, Sample Collection Forms, Soil Vapor Sampling Logs, and Photo Logs in an appendix to this report. Page 1 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. • Section General Page Comment Please complete a thorough editorial review of the documents. In some cases incorrect tables or documents have been referenced in the text, tables, and figures making the review process difficult. A few examples (but not all) of these issues are presented below. • Section 5.1.4, last paragraph, indicates the following, “As indicated in Attachment 1 of Appendix E1, the COPCs identified as potential soil hot‐spot chemicals at the Compound A Facility RFI site include arsenic and lead.” However, Attachment 1 of Appendix E1 just contains tables. It is unclear which table is being referred to or if there should be text accompanying the tables included in Attachment 1 of Appendix E1 which is missing. • Section 5.2.3, first paragraph, indicates the following, “A summary of all HQs and chemical group HIs for soil exposures are presented in Attachment 1 of Appendix E2.” However, Attachment 1 of Appendix E2 just contains tables. It is unclear which table the reader is being referred to or if text should be accompanying the tables in Attachment 1 of Appendix E2 which is missing. • Section 6.2 indicates the following, “The portions of the site outside of CMS areas do not pose unacceptable risk or hazards to the hypothetical suburban resident or small home range ecological receptors, not do they pose a threat to groundwater quality.” Should the “not” shown in bold be “nor”? • Table 5-1, Note b indicates the following, “Background risk is based on data from the Final Chemical Soil Background Study Report (DTSC, 2012).” However, DTSC 2012 as called out in Section 7 References is as follows, “California Environmental Protection Agency, Department of Toxic Substances Control (DTSC). 2012. Memorandum from Don Greenlee/DTSC to Laura Rainey/DTSC and Roger Paulson/DTSC. “HERO Comments on Group 5 Building 65 Metals Clarifier for the Santa Susana Field Laboratory (SSFL) Project, Ventura County, California.” February 21.” Please include a reference to the Final Chemical Soil Background Study Report and relabel appendices 2012a, 2012b, etc. • The following references are called out in E1 and should be included in the reference list in Section 7.0 of the main text or included in a reference list with Appendix E1 or both: • USEPA, 2011 • USEPA, 2014 • Table E1-3, Note b indicates the following, “Background risk is based on data from the Final Chemical Soil Background Study Report (DTSC, 2012).” However, two 2012 (2012a and 2012b) references are called out in Appendix E1 Section 11.0. Please review references and correct as appropriate. • Table E1-4, Note b indicates the following, “Background risk is based on data from the Radiological Background Study Report (USEPA, 2011).” No such reference is included in Section 11.0. The last reference is to MWH 2014b, is it possible many references are missing? Please review all references and update as appropriate. • Page 2 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. Section Page • General • General • Electronic Version of Report • 1.1 1-2 • 1.1 1-2 • 4 4-1 The text states that NASA and DOE’s additional data are evaluated separately. Please evaluate all of the data for STL-IV together for the final DSFR. • 4 4-1 Explain the use of boring logs and include a reference to where they are located. Either attach the boring logs to this report or verify that they are included in an administrative record document. • 4.1 4-1 The extent of 4,4’-DDT is not defined laterally or by bedrock due to lack of access due to potential impacts to an archaeological site. These and any other exceptions should be explained and justified in the DSFR. Please revise the last sentence of the third paragraph for accuracy. • 4.1 4-2; Figs. 4-6, 4-7 • 4.1.1 4-2 • 4.1.2 4-3 Comment Please include the information in this document versus just referencing a previous document. At a minimum, include a brief narrative describing the information included in the referenced document. When referencing documents please be sure to make as direct/complete of a reference as possible. Please do not reference a document that references another document which actually contains the information. Also, do not refer to a document that contains the information in an appendix or attachment but rather make a direct reference to the appendix or attachment. The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. Sections 3.4.12 and 3.4.13 of the 2007 Consent Order require the preparation of a SSFL-wide groundwater RFI report not information for a SSFL-wide groundwater report. Consider modifying template language for accuracy. Please provide the anticipated submission date for the final, comprehensive historical document deliverable. What is the fate of (or plan for) the estimated areas of impacted bedrock shown on Figure 4-6? The first paragraph on page 4-2 should, but does not, make it clear how these areas will be addressed. Are they to be evaluated in the CMS Report? Statements to such effect are needed. Also, the information on Figure 4-7 is only marginally clearer, but still should not stand alone from text. “…there are approximately 850 feet of sanitary sewer pipeline that runs through the Compound A Facility RFI site…” Present tense is used in this sentence. Verify whether the 850 feet of sanitary sewer pipeline are still in place. Verify whether the 1,500 feet of reclaimed water system pipeline is currently in place. Page 3 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. Section Page • 5.1.2 5-1 • 5.1.2 5-1 • 6.1.3 6-2 • 7 7-2 • 8.0 8-1; Fig. 4-6 • Table 3-1 1 • Table 3-1 3 • Table 4-1 SQ #1 1 • Table 4-1 SQ #4 1 • Table 4-1 SQ#4 1 • Table 4-1 SQ #2 2 • Table 4-1 SQ #2 2 Comment Typo in the last sentence: “Expose” should be “exposure.” The last sentence on page 5-1 states the following, “The garden use expose pathway scenario for the hypothetical suburban resident was also considered; the risk calculations for this exposure scenario are presented in Appendix E1.” Please summarize the risks for this scenario in Section 5 similar to the way risk for the other exposure scenarios have been presented. “The transport modeling conducted for the vadose zone to groundwater evaluation produced highly conservative results for chemicals that readily degrade…” Please remove this subjective statement. Update the date for the Reclaimed Water System Assessment. Please add the definition for “deformation band” to this Glossary and all others in the broad set of DSFRs where this term is used. However, despite the legend, Figure 4-6 shows no such feature within its frame. Please correct both these issues. Verify whether the tank inventory description should be updated to be consistent with those included in the STL-IV and STP-3 DSFRs. Under sources, update the date for the Reclaimed Water System TM. “Soil samples collected in the central portion of CUA 10 were advanced to 15 feet and did not note bedrock refusal.” The deepest sample depth shown in GIS for CUA 10 is 10 feet. Additionally the previous sentence indicates soil thickness in CUA 10 ranges from 0.5 to 11.5 feet. Further SQ#2 for Dioxins and Furans indicates the following, “Soil: Fifty‐six samples were collected from 31 locations from 0 to 11.5 feet bgs between 2000 and 2014 and were analyzed for dioxins and furans.” SQ#2 for metals also discusses samples collected from 0 to 11.5 feet. Please verify and correct these discrepancies. This section mentions the separate evaluation of DOE data. The DOE data should be evaluated with the Boeing data for the final DSFR. (See comment #1 above.) The text indicates the following, “The results of the separate evaluation of DOE data provided after preparation of this DSFR had commenced indicated that benzo(a)pyrene and dioxin and furan TEQ for mammals are risk drivers for future suburban residents…” Please provide further rationale for why the dioxin and furan TEQ for mammals is a risk driver for a suburban resident. The energetics data described is included in the filterable data but isn’t shown in the GIS energetics layer. Verify whether any discussion is needed on metals other than silver. In addition, consider mentioning that silver is defined to below SCLs or bedrock outside of the CUA cluster. Page 4 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment • Table 4-1 SQ #2 2 • Table 4-1 SQ #3 2 • Table 4-1 SQ #3 3 Typo under migration of VOCs to air. Reference is made to CC1 when it should likely be CC2. • Table 4-1 SQ #2 7 Add narrative about the nature and extent of metals other than cadmium. • GIS N/A • Table 4-1 SQ #2 8 • Table 4-1 SQ #2 9 • Table 4-1 SQ #1 9 • Table 4-1 SQ #2 9 Justify why soil vapor sampling was not conducted as part of the sanitary sewer system evaluation. • Table 4-1 SQ #2 10 In the description for radionuclides, please revise the text for clarity. • Tables 4-2 & 4-3 N/A These were not included in the PDF as stated in the hard copy. Please include them in the final report. • Table 4-4 SQ #3 3 • Figure 1-1 N/A Verify whether an inset should be added to show the RFI Groups. They are delineated but not labelled on this figure. • Figures 4-3a through 4-5b N/A If DOE or NASA data are used in the evaluation for characterization completeness, it should be presented in the figures and data tables. GIS shows a radiological exceedance at S-5, but the data are not included in the filterable data and are not described in Table 4-1. Verify whether additional sampling is needed to delineate the downstream extent. The following template language is used throughout this table: “All other chemicals were detected in the vadose zone at concentrations that are protective of groundwater.” Remove this statement or modify it to put it in context with the model evaluation. Update the water conveyance GIS layer to include the newly identified spray heads in Compound A. Justify why soil vapor sampling was not conducted as part of the reclaimed water system evaluation. “Radionuclides are not a contaminant associated with the reclaimed water system from sources in Boeing RFI Subarea 5/9 South.” This statement does not agree with Table 1 of the Reclaimed Water TM. Revise the text for accuracy. “Sanitary sewage was potentially conveyed from Administrative Area II towards the sewage treatment plant at the STP-3 RFI site.” Consider adding narrative to explain the use of the word “potentially.” Verify what additional data is needed to answer SQ #3 “yes” instead of “no.” Verify whether sampling groundwater for dichloroprop is required. Page 5 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Compound A Facility Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment • Appendix A2 General Verify whether excavated data should also be included in these tables or elsewhere in the report as the 60% template for EEL RTC #5 indicates. • Appendix C Figure C-3 • Appendix E1 and E2 General • Appendix E1 Page 3 • Appendix E2 Section 6.0 Page 11 • Appendix E4 Page 7 In the figure, the symbol for soil results is an orange circle, but in the legend it is shown as an orange triangle. Resolve the discrepancy. Please include a Table of Contents, List of Tables, List of Figures, and List of Abbreviations and Acronyms for E1 (HHRAs) and E2 (ERAs). This will help the reader review the reports. The last indented bullet states the following, “If the maximum detection was above the background comparison value but below two times that value, a more rigorous statistical evaluation was conducted to determine whether the population of site data was statistically different than the background population, as described in Section 3.3 of the SRAM Rev. 2 Addendum.” The subsequent paragraph then states the following, “The results of the population statistical comparisons of Compound A Facility RFI site soil concentrations with background comparison values are provided in Table 4 of Attachment 1.” Section 3.3 of the SRAM Rev. 2 Addendum does not describe the statistical process used for the comparison. This information appears to be included in Section 3.3 of Attachment 1 to the SRAM Rev. 2 Addendum. Please include a brief description of the process used to conduct the statistical comparison in the Compound A report and then refer to Section 3.3 of Attachment 1 to the SRAM Rev. 2 Addendum. Please make this revision in other site reports as well. Potential typo: The CH2M Hill, 2013b reference includes “STP-3.” Verify whether this should be “Compound A” instead. st Typo in 1 bulleted item: “Pervious” should be “previous.” Page 6 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. Section 1 General 2 General 3 General 4 General 5 General 6 General Page Comment CMS and NFA areas were included in the report for the suburban residential scenario and ecological risk for the high RBSL, inappropriately implying cleanup will occur based on these scenarios in the RFI Report. Further, the development of the CMS and NFA areas included risk management decisions that are exclusively made by DTSC. Please remove the CMS and NFA areas from the document. Total incremental ELCR risks for human health (i.e., summation of chemical and radiological carcinogenic risks) were not presented in the RFI Report. The reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, including intake from ingesting homegrown fruits and vegetables. The reports incorrectly assumed that the high ecological RBSL could be utilized to develop CMS and NFA areas. Please evaluate the utility of the high and low ecological RBSL in the uncertainty analysis section of the risk assessment included in Appendix E2 so risk management decisions relating to the use of the low or high RBSL can be assessed by DTSC. Please provide Field Log Books, Boring/Trench Logs, Sample Collection Forms, Soil Vapor Sampling Logs, and Photo Logs in an appendix to this report. Please complete a thorough editorial review of the documents. In some cases incorrect tables or documents have been referenced in the text, tables, and figures making the review process difficult. A few examples (but not all) of these issues are presented below. nd • Section 3-1, 2 paragraph, 17 CUAs are called out in Table 3-2 and shown in Figure 3-1, not sixteen. • Section 5.1.4, last paragraph, indicates the following, “As indicated in Attachment 1 of Appendix E1, the COPCs identified as potential soil hot‐spot chemicals at the EEL RFI site include arsenic, 2,3,7,8‐TCDD TEQ and benzo(a)pyrene.” However, Attachment 1 of Appendix E1 just contains tables. It is unclear which table is being referred to or if there should be text accompanying the tables included in Attachment 1 of Appendix E1 which is missing. • Section 5.2.3, first paragraph, indicates the following, “A summary of all HQs and chemical group HIs for soil exposures are presented in Attachment 1 of Appendix E2.” However, Attachment 1 of Appendix E2 just contains tables. It is unclear which table the reader is being referred to or if text should be accompanying the tables in Attachment 1 of Appendix E2 which is missing. • Appendix E3 indicates the following, “The CMS areas delineated using this process are depicted on Figure 4-7 of the EEL Report.” Figure 4-7 in the EEL Report presents the foot print of impacted groundwater not CMS areas. Please include the information in this document versus just referencing a previous document. At a minimum, include a brief narrative describing the information included in the referenced document. Page 1 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. Section Page 7 General 8 Electronic Version of Report 9 1.1 1-2 10 1.1 1-2 11 4 4-1 12 4 4-1 13 4.1.1 4-2 14 4.1.2 4-3 15 5.1.2 5-1 16 4.1 4-2; Fig. 4-6 Comment When referencing documents please be sure to make as direct/complete of a reference as possible. Please do not reference a document that references another document which actually contains the information. Also, do not refer to a document that contains the information in an appendix or attachment but rather make a direct reference to the appendix or attachment. The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. Sections 3.4.12 and 3.4.13 of the 2007 Consent Order require the preparation of a SSFL-wide groundwater RFI report, not information for a SSFL-wide groundwater report. Consider modifying template language for accuracy. Please provide the anticipated submission date for the final, comprehensive historical document deliverable. The additional data provided by DOE after preparation of the DSFR should be incorporated with the rest of the site data for the final versions of the report. Please evaluate all of the data for STLIV together for the final DSFR. The statement that “Additional data were collected by DOE and provided to Boeing after preparation of the EEL DSFR had commenced” should be removed from the final version of the report. This section needs to include explanation for the use of boring logs and reference to where they are located. Either attach the boring logs to this report or verify that they are included in an administrative record document. Stated in this section is “…there are approximately 750 feet of sanitary sewer pipeline and two sanitary sewer manholes within the EEL RFI site.” Since the present tense is used in this sentence, verify whether the 750 feet of sanitary sewer pipeline and two sewer manholes are still in place. This comment also applies to Table 4-1. Please verify whether the “approximately 550 feet of reclaimed water pipeline within the EEL RFI site” are still in place. This comment also applies to Table 4-1. The last sentence on page 5-1 states the following, “The garden use exposure pathway scenario for the hypothetical suburban resident was also considered; the risk calculations for this exposure scenario are presented in Appendix E1.” Please summarize the risks for this scenario in Section 5 similar to the way risk for the other exposure scenarios have been presented. What is the fate of (or plan for) the estimated areas of impacted bedrock shown on Figure 4-6? The first paragraph on this page should, but does not, make it clear how these areas will be addressed. Are they to be evaluated in the CMS Report? Statements to such effect are needed. The information on Figure 4-7 is only marginally clearer, but still should not stand alone from text. Page 2 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. Section Page 17 Table 3-1 5 18 Table 3-2 all 19 Table 3-2 3-2 20 Table 4-1 SQ #2 2 21 Table 4-1 SQ #3 2 22 Table 4-1 SQ #2 2, 3 23 Table 4-1 3 24 Table 4-1 3 Comment Under “Sources,” please see comment 15 regarding the Reclaimed Water System TM. Also note the “2015c” (Section 7 reference) versus the “2015b” in Table 3-1. The Section 7 is the main reference list, takes precedence over all other lists; remaining in effect throughout the document. Please explain the purpose and use of the “Waste Oils” column in this table for this site; there are no entries. The entries in Table 4-1 notwithstanding, was the historical information about tanks detailed enough to distinguish between hydraulic oil and waste oil tanks in all such cases? If not, should the waste oil column be subsumed within the “Oil-Related Materials” column; especially since the target analytical suites are the same? Section 2.1 indicates that storage tanks were mostly used to store gases and hydraulic oil. Is the fact that two additional columns, Debris Areas/Fill and Leach Field, in this table also have no entries meant to convey that such CUAs do not exist at EEL? Both are redundant to the entries in Table 3-1. The energetics data described here is included in the filterable dataset, but are not shown in the GIS energetics layer. Please explain or provide. Please either remove the following template statement or modify it to put it in context with the model evaluation: “All other chemicals were detected in the vadose zone at concentrations that are protective of groundwater.” Please verify whether any further discussion is needed on metals other than arsenic or “hex chrome,” including nature and extent. For “Radionuclides” under Study Question #2, it is stated that “Strontium‐90 was detected above the SCL in one sample within the drainage channel at the western end of the EEL RFI site reporting area. The upstream and downstream extent of strontium‐90 is defined by samples with results below SCLs. However, these bounding locations and their data are not provided in the “RAD_Q2_2015.mdb” dataset (presumably where they may be found if named) and, thus, are not viewable in GIS. Please provide or explain in what other viewable or searchable database file(s) they may be found. In addition, this same table section cited above in comment 4 states that “No other radionuclides were detected at concentrations exceeding SCLs.” This statement does not make clear whether it applies only to the five samples or generally to the sampled EEL soil. Please clarify. If the intent is to be general, then the statement is incorrect since radionuclides other than Sr90 were detected at EEL above residential and/or characterization levels. Moreover, the fact that such other exceedances were found needs to be acknowledged, with reference to where in document they are addressed. Page 3 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment 25 Table 4-1 SQ #2 4 through 6 Radionuclides are addressed in Table 4-1 for the Sanitary Sewer System at EEL, but not for the Reclaimed Water System (RWS). However, they are addressed for the RWS in Table 4-1 for Compound A. Yet, Table 1 in the Reclaimed Water TM has radionuclides as “Other” “Potentially Associated Constituents Identified for the Reclaimed Water System” in Subarea 5/9-South, including EEL. Please provide the appropriate statement(s) in Table 4-1 that maintain the needed accuracy and consistency between these documents. 26 Tables 4-2 & 4-3 N/A As stated, these tables were not included in the hard copy. Please include them in the final report. 27 Figures 4-1 through 4-7; Figure 6-1 N/A To the extent that DOE data are used in the evaluation for characterization completeness, they should be presented in figures as well as data tables. See also comment 4. 28 Figure 4-6 N/A What do the green and red dots mean that are depicted on the figure. Are these samples that were collected in the bedrock vadose zone or soil vadose zone? Please add this information to the legend. 29 6.1 6-1 Typos: the words “size” and “shape” should be plural; “…sizes and shapes…” 30 6.1.3 6-2 31 6.1.3 6-2 32 7 7-2 33 8.0 8-1; Fig 4-6 34 Appendix A2 General 35 Appendix C Attachment C 36 Appendix C Attachment C 37 Appendix E1 and E2 General The second paragraph mentions “additional data collected at the site by DOE.” Where were those data collected; on the DOE or Boring sides of the site, or both? Please clarify. The third paragraph states that “…transport modeling conducted for the vadose zone to groundwater evaluation produced highly conservative results for chemicals…” Please remove the words “highly conservative.” Please verify the date for the “Reclaimed Water System Assessment” reference. Also note that this same reference has “January” in this volume, but the Compound A DSFR has “February.” What is the definition of a “deformation band?” This term should be added to this Glossary and all others in the broad set of DSFRs where this term is used. However, despite the legend, Figure 4-6 shows no such feature within its frame. Please correct both these issues. Verify whether excavated data should also be included in these tables or elsewhere in the report as the 60% template for EEL RTC #5 indicates. A concentration of 26.1 ug/g for 1,1-DCE appears to have been used for the majority of the A/C and WS/UWS portion of the profile. This concentration cannot be located in the filterable dataset. How is the concentration used in the profile being determined for evaluation of 1,1-DCE? A concentration of 0.099 ug/g for di-n-octyl phthalate appears to have been used for the majority of the A/C and WS/UWS portion of the profile. This concentration cannot be located in the filterable dataset. How is the concentration used in the profile being determined for evaluation of di-n-octyl phthalate? Please include a Table of Contents, List of Tables, List of Figures, and List of Abbreviations and Acronyms for E1 (HHRAs) and E2 (ERAs). This will help the reader review the reports. Page 4 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. 38 Section EEL Report Page Appendix E1, Page 2 39 EEL Report Appendix E1 40 EEL Report Appendix E1, Page 6 41 EEL Report Appendix E1, Table E1-4 Comment Section 4.0, first paragraph states the following: “Table 3-1 of this EEL DSFR summarizes the nature and extent and fate and transport evaluations performed for soil, soil vapor, and vadose zone bedrock at the EEL RFI site. Figures 4-1 through 45 of this EEL DSFR present summaries of the soil and soil vapor characterization that has been performed to date at the EEL RFI site. Table 3-2 of this EEL DSFR summarizes the nature and extent and fate and transport evaluations performed for groundwater beneath and downgradient from the EEL RFI site. Figure 4-7 of this EEL DSFR presents the estimated footprint of impacted groundwater at the EEL RFI site.” Tables 3-1 presents a comprehensive summary of the weight‐of‐evidence assessment of any known or potential release of any chemical previously used, stored, handled, or disposed within the EEL RFI site; this table serves to document the completeness of the DQO process for identifying potential contamination sources. Table 3-2 presents the chemical use summary for the EEL RFI site. Neither of these tables presents nature and extent and fate and transport evaluations as indicated in the Section 4.0 text quoted above. Please identify and call out the appropriate table in the text. Additionally, please check all table, figure, appendix, attachment, and reference call outs. Why isn’t a table included that evaluates chemical risk from 0-10 feet, similar to what is included for the 0-2 foot interval in Table E1-5? The information for the 0-10 foot interval is summarized in Table E1-3 and the detail used to develop the risk estimates should be in the report. The last sentence in Section 8.1.1.1 states the following, “For the direct contact with soil pathway, -7 6 4 the total site ELCR is 2 x 10 , which is below the USEPA target risk range of 1 x 10‐ to 1 x 10‐ 6 and below the DTSC point of departure of 1 x 10‐ .” This does not match the information presented in Table E1-4 which indicates there is unacceptable incremental risk of 2E-06 for the direct contact with soil pathway. Please resolve the inconsistences and if necessary carry radiological risk evaluation in to the residual risk evaluation included in Appendix E3. The electronic version of Table E1-4 does not match the hard copy version. There also appears to be mathematical errors in both tables. Please revise the tables to address these issues. Page 5 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Environmental Effects Laboratory Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment The reference to a January 14, 2015 email from M Bower to R Paulson involves the submittal of rad RBSLs that were not approved before the report was issued. Please remove the reference and describe the development of rad RBSLs, including the status of the approval. It may be preferable to include the complete rad RBSL set in Attachment 1 for approval. Below is a summary of the development RBSLs used in the RFI data gap risk assessments Boeing has submitted to date. 42 EEL Report Appendix E1, Attachment 1, Text, Section 1.0 43 EEL Report Appendix E2, Table E2-15 44 EEL Report Appendix E2, Attachment 1, Tables 8 and 9 45 EEL Report Appendix E4, Page 5 • In September 2013, Boeing submitted Draft Soil Characterization Levels for Radionuclides in the Draft Boeing 1B SW Data Gap Work Plan Addendum for Area I Burn Pit. • In November 2013, DTSC sent Boeing a letter to recalculate the Soil Characterization Levels by selecting the higher value of a radionuclide’s background value (Upper Threshold Limit), or it’s USEPA Residential Preliminary Remediation Goal (PRG) for a one in a million (10-6) risk level. • In January 2014, Boeing submitted revised rad RBSLs, but DTSC did not complete review before the Subarea 5/9 South and Subarea 1A Central reports were submitted. o The rad RBLS that were submitted but not reviewed and approved are included and used in the Subarea 5/9 south and Subarea 1A Central reports. • Additional Risk-Based Screening Levels (RBSLs) for Recently Detected Chemicals and Radionuclides were submitted as Appendix E1, Attachment 1 of the Draft RCRA Facility Investigation Data Summary and Findings Report (Draft EEL Report) for the Environmental Effects Laboratory RFI Site in Subarea 5/9 south at the Santa Susana Field Laboratory. The last row in this table states, “Data necessary to estimate potential risks from all pathways for all chemicals in the food-chain uptake model were not always available. For these chemicals and/or areas, the food‐chain uptake model was completed using the available data.” Please provide additional detail regarding what information is not available. Include a note on the Type column indicating what the “I” and “O” mean. The first paragraph on page 5 states the following, “Removal of the data for these three samples from the residual risk data set results in a residual incremental excess lifetime cancer risk and hazard index that does not exceed the DTSC point of departure of 1 x 10‐6 and the hazard index threshold of 1 for the 0 to 2 feet bgs and 0 to 10 feet bgs depth intervals for the suburban resident, or the High EcoRBSLs for the 0 to 2 feet or 0 to 6 feet bgs depth intervals for ecological receptors.” Please provide the risk calculations for review. Page 6 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Area III Sewage Treatment Plant Santa Susana Field Laboratory, Ventura County, California No. Section 1 General 2 General 3 General 4 General 5 General Page Comment CMS and NFA areas were included in the report for the suburban residential scenario and ecological risk for the high RBSL, inappropriately implying cleanup will occur based on these scenarios in the RFI Report. Further, the development of the CMS and NFA areas included risk management decisions that are exclusively made by DTSC. Please remove the CMS and NFA areas from the document. Incremental ELCR for human health from soil for chemical and radiological risk was inappropriately calculated by subtracting the background risk from the total Site risk by media. Background risk for some analytes was higher than total site risk for chemicals and radionuclides of potential concern (COPCs, ROPCs) where the 95 percent upper confidence limit (UCL) for background is greater than the 95 percent UCL for the site. When this occurred for risk drivers (e.g., arsenic and other analytes in the 5/9 South STL IV RFI DSFR), the incremental Site risk was reported as “NR” or “no incremental risk over background”. This reporting practice gives the appearance of “masking” the incremental Site risk contributed by other COPCs and ROPCs. In the tables that present total site cancer risk and hazard quotients (HQ), background cancer risk and HQ, and incremental cancer risk and HQ for each COPC, sum the total site risk and HQs and incremental risks and HQs. The summation should be included for each exposure scenario. Where any COPC or ROPC is a “driver” or “major contributor” to the total Site cancer risk or HQ (as defined in Appendix J of the SRAM Revision 2 Addendum), and the background cancer risk or HQ exceeds the total site cancer risk or HQ, then exclude the cancer risk or HQ for the COPC or ROPC from calculation of the incremental ELCR cancer risk and HQ. Evaluate the data for these Site COPCs or ROPCs using the Hot Spot Evaluation method per Appendix J of the SRAM Revision 2 Addendum. Total incremental ELCR risks for human health (i.e., summation of chemical and radiological carcinogenic risks) were not presented in the RFI Report. The reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, including intake from ingesting homegrown fruits and vegetables. The reports incorrectly assumed that the high ecological RBSL could be utilized to develop CMS and NFA areas. Please evaluate the utility of the high and low ecological RBSL in the uncertainty analysis section of the risk assessment included in Appendix E2 so risk management decisions relating to the use of the low or high RBSL can be assessed by DTSC. Please provide Field Log Books, Boring/Trench Logs, Sample Collection Forms, Soil Vapor Sampling Logs, and Photo Logs in an appendix to this report. Page 1 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Area III Sewage Treatment Plant Santa Susana Field Laboratory, Ventura County, California No. Section 6 General 7 General 8 General 9 Electronic Version of Report 10 1 Page Comment Please complete a thorough editorial review of the documents. In some cases incorrect tables or documents have been referenced in the text, tables, and figures making the review process difficult. A few examples (but not all) of these issues are presented below. • Section 2 states the following, “Additional detailed information on the historical use and site conditions at the STP‐3 RFI site are presented in the Draft STP‐3 RFI Site Report (CH2M, 2008) and the STP‐3 Work Plan Addendum (CH2M, 2013c)” The references included in the reference section are as follows: • CH2M HILL (CH2M). 2008. Group 5 – Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. • CH2M HILL (CH2M). 2013a. Master Resource Conservation and Recovery Act Facility Investigation Data Gap Work Plan. March.CH2M HILL. 2013b. Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. A document called “Draft STP-3 RFI Site Report” document as implied by the text does not appear to be called out in the CH2M 2008 reference. Additionally, a document called “STP‐ 3 Work Plan Addendum” document as implied by the text does not appear to be called out in the CH2M 2013a reference. Please check and update the text or reference as appropriate. • Section 3.2.1 calls out a CH2M 2014b but a reference to CH2M, 2014b is not included in Section 7. Please check and revise. • Section 7, the references for CH2M 2013a and 2013b were combined. It appears a space should have been included between the references. Please check and fix as appropriate. Please include the information in this document versus just referencing a previous document. At a minimum, include a brief narrative describing the information included in the referenced document. When referencing documents please be sure to make as direct/complete of a reference as possible. Please do not reference a document that references another document which actually contains the information. Also, do not refer to a document that contains the information in an appendix or attachment but rather make a direct reference to the appendix or attachment. The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. 1-1 Typo in the first sentence: Plan should be Plant in Sewage Treatment Plant. Page 2 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Area III Sewage Treatment Plant Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment 11 1.1 1-2 12 1.1 1-2 13 3.1 3-1 14 4 4-1 15 4.1 4-2, Figure 4-6 16 5.1.2 5-1 17 6.1.3 6-2 18 7 7-2 Update the date for the Reclaimed Water System Assessment. 19 7 7-3 Verify the date for the SRAM Revision 2 Addendum. 20 8.0 8-1, Figure 4-6 21 Table 3-1 1 Please provide the anticipated submission date for the updated Tank Inventory. 22 Table 3-1 4 Under sources, update the date for the Reclaimed Water System TM. 23 Table 4-1 N/A Sections 3.4.12 and 3.4.13 of the 2007 Consent Order require the preparation of a SSFL-wide groundwater RFI report not information for a SSFL-wide groundwater report. Consider modifying template language for accuracy. Please provide the anticipated submission date for the final, comprehensive historical document deliverable. Expand this text to describe where and how water was discharged and show the water pathway on the figures. Explain the use of boring logs and include a reference to where they are located. Either attach the boring logs to this report or verify that they are included in an administrative record document. What is the fate of (or plan for) the estimated areas of impacted bedrock shown on Figure 4-6? The first paragraph on this page should, but does not, make it clear how these areas will be addressed. Are they to be evaluated in the CMS Report? Statements to such effect are needed. The information on Figure 4-7 is only marginally clearer, but still should not stand alone from text. The last sentence on page 5-1 states the following, “The garden use expose pathway scenario for the hypothetical suburban resident was also considered; the risk calculations for this exposure scenario are presented in Appendix E1.” Please summarize the risks for this scenario in Section 5 similar to the way risk for the other exposure scenarios have been presented. “The transport modeling conducted for the vadose zone to groundwater evaluation produced highly conservative results for chemicals that readily degrade…” Please remove this subjective statement. Please add the definition for deformation band to this Glossary and all others in the broad set of DSFRs where this term is used. However, despite the legend, Figure 4-6 shows no such feature within its frame. Please correct both these issues. This table doesn’t include the total number of pages in the footer. Consider adding it (Page 1 of XX). Page 3 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Area III Sewage Treatment Plant Santa Susana Field Laboratory, Ventura County, California No. Section Page 24 Table 4-1 SQ #2 2 25 Table 4-1 SQ #3 2 26 Table 4-1 SQ #1 3 27 Table 4-1 SQ #2 4 28 Tables 4-2 & 4-3 N/A 29 Table 4-4 SQ #2 1 30 Figure 1-1 N/A 31 Figure 4-1 N/A 32 Figure 4-5 N/A 33 Appendix A N/A 34 Appendix C C.3 Page C-8 35 Appendix C 36 Attachment C-5 37 Appendix C Attachments Figures C-3 and C-5 SESOIL Hydrologic Cycle Report SESOIL Pollutant Cycle Reports Comment STP-3 serviced numerous buildings in Area IV where radionuclides were handled, and Table 1 in the Sanitary Sewer TM identifies radionuclides as a potential input to STP-3. Please expand the narrative to better recognize the probable input from Area IV. The following template language is used throughout this table: “All other chemicals were detected in the vadose zone at concentrations that are protective of groundwater.” Remove this statement or modify it to put it in context with the model evaluation. This list of potential chemicals used/stored doesn’t include all of the chemicals that were listed in the Reclaimed Water TM. Verify that the subarea scale evaluation of terphenyls and radionuclides is documented in the subarea report and reference that here. These were not included in the PDF as stated in the hard copy. Please include them in the final report. Under VOCs, it states that “VOCs were detected at concentrations above their screening levels in groundwater but not in the vadose zone.” However, two locations had SCL exceedances for VOCs. Please resolve this discrepancy. Verify whether an inset should be added to show the RFI Groups. They are delineated but not labelled on this figure. For ELSV1402, the filterable data indicates that toluene had an SCL exceedance, which matches Figure 4-1. However, GIS shows this sample location as blue (<=CL). Please verify. Verify the refusal depths for STBS1017 and STBS1018. In GIS, the refusal depth is shown as 9’ and 9.5’, but lists a sample depth of 10-11’ bgs. Please resolve the discrepancy and provide the associated boring logs. Please include a notes section at the end of each table for acronyms and abbreviations. Possible typo: In the second to the last paragraph, “…in the third quarter of 2014.” is stated twice for WS-11 in the first sentence. In the figures, the symbol for soil results is an orange circle, but in the legend it is shown as an orange triangle. Resolve the discrepancy. The key on the right side of several figures is cut off on both sides of the page. Please include the cut off portions. The data point values on the four yellow graphs on the back side of the page are also very difficult to read. Many of the SESOIL Pollutant Cycle Report graphs have the right side of the graph or key cut off. Please include the cutoff portions. Page 4 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Area III Sewage Treatment Plant Santa Susana Field Laboratory, Ventura County, California No. Section Page 38 Appendix E1 and E2 General 39 Table E1-3 1 Comment Please include a Table of Contents, List of Tables, List of Figures, and List of Abbreviations and Acronyms for E1 (HHRAs) and E2 (ERAs). This will help the reader review the reports. In the groundwater row, the text is cut off. Page 5 of 5 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section 1 General 2 General 3 General 4 General 5 General Page Comment CMS and NFA areas were included in the report for the suburban residential scenario and ecological risk for the high RBSL, inappropriately implying cleanup will occur based on these scenarios in the RFI Report. Further, the development of the CMS and NFA areas included risk management decisions that are exclusively made by DTSC. Please remove the CMS and NFA areas from the document. Incremental ELCR for human health from soil for chemical and radiological risk was inappropriately calculated by subtracting the background risk from the total Site risk by media. Background risk for some analytes was higher than total site risk for chemicals and radionuclides of potential concern (COPCs, ROPCs) where the 95 percent upper confidence limit (UCL) for background is greater than the 95 percent UCL for the site. When this occurred for risk drivers (e.g., arsenic and other analytes in the 5/9 South STL IV RFI DSFR), the incremental Site risk was reported as “NR” or “no incremental risk over background”. This reporting practice gives the appearance of “masking” the incremental Site risk contributed by other COPCs and ROPCs. In the tables that present total site cancer risk and hazard quotients (HQ), background cancer risk and HQ, and incremental cancer risk and HQ for each COPC, sum the total site risk and HQs and incremental risks and HQs. The summation should be included for each exposure scenario. Where any COPC or ROPC is a “driver” or “major contributor” to the total Site cancer risk or HQ (as defined in Appendix J of the SRAM Revision 2 Addendum), and the background cancer risk or HQ exceeds the total site cancer risk or HQ, then exclude the cancer risk or HQ for the COPC or ROPC from calculation of the incremental ELCR cancer risk and HQ. Evaluate the data for these Site COPCs or ROPCs using the Hot Spot Evaluation method per Appendix J of the SRAM Revision 2 Addendum. Total incremental ELCR risks for human health (i.e., summation of chemical and radiological carcinogenic risks) were not presented in the RFI Report. The reports must present cumulative risks as the sum of chemical and radiological risks for a residential receptor, including intake from ingesting homegrown fruits and vegetables. The reports incorrectly assumed that the high ecological RBSL could be utilized to develop CMS and NFA areas. Please evaluate the utility of the high and low ecological RBSL in the uncertainty analysis section of the risk assessment included in Appendix E2 so risk management decisions relating to the use of the low or high RBSL can be assessed by DTSC. Please provide Field Log Books, Boring/Trench Logs, Sample Collection Forms, Soil Vapor Sampling Logs, and Photo Logs in an appendix to this report. Page 1 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section 6 General 7 General Page Comment Please complete a thorough editorial review of the documents. In some cases incorrect tables or documents have been referenced in the text, tables, and figures making the review process difficult. A few examples (but not all) of these issues are presented below. • Section 2 states the following, “Additional detailed information on the historical use and site conditions at the STL‐IV RFI site are presented in the Draft STL‐IV RFI Site Report (CH2M HILL, 2008) and the STL‐IV Work Plan Addendum (CH2M HILL, 2013c)” The references included in the reference section are as follows: • CH2M HILL (CH2M). 2008. Group 5 – Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. • CH2M HILL (CH2M). 2013a. Master Resource Conservation and Recovery Act Facility Investigation Data Gap Work Plan. March.CH2M HILL. 2013b. Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. A document called “Draft STL‐IV RFI Site Report” document as implied by the text does not appear to be called out in the CH2M 2008 reference. Additionally, a document called “STL‐ IV Work Plan Addendum” document as implied by the text does not appear to be called out in the CH2M 2013a reference. Please check and update the text or reference as appropriate. • Section 5.1.4, last paragraph, indicates the following, “As indicated in Attachment 1 of Appendix E1, the COPCs identified as potential soil hot‐spot chemicals at the Compound A Facility RFI site include arsenic and lead.” However, Attachment 1 of Appendix E1 just contains tables. It is unclear which table is being referred to or if there should be text accompanying the tables included in Attachment 1 of Appendix E1 which is missing. • Table 5-1, Note b indicates the following, “Background risk is based on data from the Final Chemical Soil Background Study Report (DTSC, 2012).” However, DTSC 2012 as called out in Section 7 References is as follows, “California Environmental Protection Agency, Department of Toxic Substances Control (DTSC). 2012. Memorandum from Don Greenlee/DTSC to Laura Rainey/DTSC and Roger Paulson/DTSC. “HERO Comments on Group 5 Building 65 Metals Clarifier for the Santa Susana Field Laboratory (SSFL) Project, Ventura County, California.” February 21.” Please verify the reference and update it as appropriate. Please include the information in this document versus just referencing a previous document. At a minimum, include a brief narrative describing the information included in the referenced document. Page 2 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section Page 8 General 9 Electronic Version of Report 10 1.1 1-2 11 1.1 1-2 12 3.2.1 3-2 13 3.2.2 3-2 14 4 4-1 15 4 4-1 16 4.1 4-2, Figure 4-6 17 4.1.2 4-2 18 5.1.2 5-1 and 5-2 Comment When referencing documents please be sure to make as direct/complete of a reference as possible. Please do not reference a document that references another document which actually contains the information. Also, do not refer to a document that contains the information in an appendix or attachment but rather make a direct reference to the appendix or attachment. The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. Sections 3.4.12 and 3.4.13 of the 2007 Consent Order require the preparation of a SSFL-wide groundwater RFI report not information for a SSFL-wide groundwater report. Consider modifying template language for accuracy. Please provide the anticipated submission date for the final, comprehensive historical document deliverable. The final sentence of this section states the following, “Appendix B presents the final conclusions for the air dispersion pathway for the STL‐IV RFI site.” Please include a brief summary of the conclusions of the air dispersion modeling in this section or elsewhere in the main body of the RFI DSFR report. Verify how the planned Vapor Intrusion Evaluation Summary Technical Memorandum will present the details and evaluation of the additional VI investigation activities proposed in the 5/9 South VI TM (February 2015). The text states that DOE’s additional data are evaluated separately. Please evaluate all of the data for STL-IV together for the final DSFR. Explain the use of boring logs and include a reference to where they are located. Either attach the boring logs to this report or verify that they are included in an administrative record document. What is the fate of (or plan for) the estimated areas of impacted bedrock shown on Figure 4-6? The first paragraph on this page should, but does not, make it clear how these areas will be addressed. Are they to be evaluated in the CMS Report? Statements to such effect are needed. The information on Figure 4-7 is only marginally clearer, but still should not stand alone from text. Typo in the last sentence: The texts states that there are three ponds but only mentions two (Impoundments 1 and 2). Resolve the discrepancy. The last sentence on page 5-1 states the following, “The garden use expose pathway scenario for the hypothetical suburban resident was also considered; the risk calculations for this exposure scenario are presented in Appendix E1.” Please summarize the risks for this scenario in Section 5 similar to the way risk for the other exposure scenarios have been presented. Page 3 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section Page 19 6.1.3 6-3 20 6.2 6-5 21 7 7-2 22 8.0 8-1, Figure 4-6 23 Table 3-1 1 Please provide the anticipated submission date for the updated tank inventory. 24 Table 3-1 4 Under sources, update the date for the Reclaimed Water System TM. 25 Table 4-1 SQ #1 2 Under CUA 9, Building 3318 is listed twice. Verify whether one of the references is a typo. 26 Table 4-1 SQ #2 Rads 27 Table 4-1 SQ #3 2 28 Table 4-1 SQ #2 VOCs 4 29 Table 4-1 SQ #2 6 Potential typo in the last sentence: GIS indicates soil thickness up to 16’ for CC4, not 10’ as stated. 30 Table 4-1 SQ #2 Rads 8 Verify how the lateral and vertical extents of Strontium-90 detected above the SCL are defined. 31 Table 4-1 SQ #2 d/f 10 32 Table 4-1 SQ #2 d/f 17 2 Comment “The transport modeling conducted for the vadose zone to groundwater evaluation produced highly conservative results for chemicals that readily degrade…” Please remove this subjective statement. This section refers to EEL and Figure 6-1 when it should refer to STL-IV and Figures 6-1a and 61B. Please resolve this typo. Update the date for the Reclaimed Water System Assessment. Please add the definition for deformation band to this Glossary and all others in the broad set of DSFRs where this term is used. However, despite the legend, Figure 4-6 shows no such feature within its frame. Please correct both these issues. Radionuclides are not listed under Study Question #2 despite sample S-4 collected in STL-IV Impoundment 1. In addition, this sample exceeded SCLs for Radium-226, Potassium-40, and Uranium-238 according to GIS. It is not included in the filterable data. Verify whether additional sampling is needed to delineate the lateral and vertical extent of radionuclides in this area. The following template language is used throughout this table: “All other chemicals were detected in the vadose zone at concentrations that are protective of groundwater.” Remove this statement or modify it to put it in context with the model evaluation. Under Soil Vapor, verify the wording for the first sentence. Several words seem to have been left out. Under soil, verify whether the first sentence contains a typo (“Thirteen soil samples were collected at 21 locations…”). The dioxins and furans description includes template language that is not as applicable to this CC because it is well outside the historical operational areas of STL-IV. Consider modifying the text accordingly. Page 4 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section Page 33 Table 4-1 SQ #2 Rads 18 34 Table 4-1 SQ #3 18 35 Table 4-1 SQ #3 19 See comment #33 above. Do a global check for this template language to ensure clarity. 36 Table 4-1 19 A section is included for SCL exceedances outside CUA clusters. Please provide additional explanation for this section and why these exceedances are addressed separately instead of being included in the closest CUA cluster. 37 Table 4-1 SQ #3 19 Verify how the lateral and vertical extent of the Cesium-137 SCL exceedance is characterized. 38 Table 4-1 SQ #4 19 Verify the first few sentences. A reference is made to STL-IV CC 11. Is this a typo? 39 Table 4-1 SQ #4 19 40 Table 4-1 SQ #1 20 41 Table 4-1 SQ #2 21 42 Table 4-1 SQ #2 22 43 Table 4-1 SQ #2 22 44 Table 4-1 23 Sources Comment The text states that one sample was “…analyzed for radionuclides to assess migration from upgradient Area II sources where radiological materials were used.” Verify whether this is correct. Potential typo: “…transport modeling estimated they would impact groundwater at concentrations above screening levels during the 100 year model simulation.” Verify whether this should say “would not impact groundwater.” Please provide additional information about the presence of perchlorate in the vadose zone and groundwater. GIS shows that it was detected in the nearby soil at SLBS2048 (below the SCL), but the filterable data and table 4-4 indicate that “Perchlorate was not detected in recent or historical samples collected from well locations interpreted to monitor and contain groundwater representative of the STL-IV RFI site.” (The nearest to the vadose zone CMS area is more than 300’ away.) st st Verify the publish dates for the 1 Iteration WPs. The STL-IV 1 Iteration WP was published in April 2013, not May 2013. In addition, the EEL site is referenced under Potential CUA I. The text asserts that “Radionuclides do not appear to have migrated via the reclaimed water system to the STL-IV RFI site.” Provide support for this statement or remove it. Also, verify whether the extent of radionuclides exceeding SCLs is defined. The text states that “Pesticides and dioxins and furans do not appear to have migrated from Administrative Area IV to Boeing RFI Subarea 5/9 South via the sanitary sewer system…” Provide justification supporting this assertion. “Based on the isolated detections of radionuclides above their SCLs and their limited extent within the Boeing RFI subarea…” Please explain the meaning of “isolated detections.” This is a difficult case to make with SCL exceedances that are not bound with step out samples. Verify whether the Reclaimed Water TM (July 2015) should be added to this list. Page 5 of 6 DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Systems Test Laboratory IV Santa Susana Field Laboratory, Ventura County, California No. Section Page Comment 45 Tables 4-2 & 4-3 N/A These were not included in the PDF as stated in the hard copy. Please include them in the final report. 46 Figure 1-1 N/A Verify whether an inset should be added to show the RFI Groups. They are delineated but not labelled on this figure. 47 Figures 4-3a through 4-5b N/A If DOE or NASA data are used in the evaluation for characterization completeness, it should be presented in the figures and data tables. 48 Appendix E1 and E2 General Please include a Table of Contents, List of Tables, List of Figures, and List of Abbreviations and Acronyms for E1 (HHRAs) and E2 (ERAs). This will help the reader review the reports. 49 Appendix A2 General Verify whether excavated data should also be included in these tables or elsewhere in the report as the 60% template for EEL RTC #5 indicates. 50 Appendix C Figure C-3 51 GIS General In the figure, the symbol for soil results is an orange circle, but in the legend it is shown as an orange triangle. Resolve the discrepancy. When the identify tool is used for the radionuclide GIS layer, the top analytical result that comes up is not necessarily the one that is the highest SCL exceedance (examples: S-4 and A3_SED_DG16). Verify whether this should be corrected. Page 6 of 6 Draft DTSC Review Comments RCRA Facility Investigation Data Summary and Findings Report – June 2015 Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California No. Section Page 1 General 2 Electronic Version of Report 3 Contents III 4 6 6-1 5 6 6-1 6 Table 4-1 1 7 Table 4-2 1 8 Figures Fig. 6-1 9 Figures All Figures Comment Please provide Field Log Books, Boring/Trench Logs, Sample Collection Forms, Soil Vapor Sampling Logs, and Photo Logs (as appropriate) in an appendix to this report. The draft report appears to have random bookmarking and bookmarking of blank pages which is not helpful. Please bookmark the electronic version of the report. Bookmarking of the report by Cover Page, first page of the Executive Summary, first page of the TOC, first page of each Section, Tables cover sheet, Figures cover sheet, and the cover sheets for each appendix (at a minimum) will help conduct report reviews more efficiently. The Section numbers for the main section headings appear to be missing. Section 6 discusses the detected concentrations of GRO and compares them to a screening level of 1 mg/kg. Appropriately update the discussion in Section 6 based on the revised Table 4-1 (see comment 3). The selenium ecological low RBSL exceedance listed in Table 4-2 should be discussed in Section 6. Table 4-1 discusses that the screening level for gasoline range organics is based on the detection limit but that human health or ecological risk-based characterization levels have not been developed for TPH. Explain how screening levels and characterization levels differ. Other analytes such as diesel range organics and oil range organics were detected above their detection limits. Verify whether these are also compared to a screening level. Please include the “J” flag for the selenium result of 0.88 mg/kg in Table 4-2. This figure’s title includes areas recommended for both CMS and no further action (NFA). No CMS areas or NFA areas are identified on the map. All sites must be evaluated in the CMS. Include sample location names on figures. Without sample location names on the figures the reader cannot see where sample data included in Appendix A are located. Page 1 of 1 ?91 i a. .1 Department of Toxic Substances Control Barbara A. Lee Matthew Rodriquez Director Edmund G. Brown Jr. Secretary for Governor Environmental Protection 9211 (Jamal? AVENUE Chatsworth, California 91311 T0: Julie Lincoln, P.E. . Brown?elds and Environmentai Restoration Program DTSC-Sacramento FROM: Donald v. Greenlee,Ph.D.,DABT Staff Toxicologist DATE: April 5, 2016, revised July 15, 2016 SUBJECT: HERO Comments on the ?Human Health and Ecological Risk Assessment for Surface Water in the Southwest Drainage of Boeing RFI Subarea 519 South" (Appendix D), contained in the Facility Investigation Data Summary and Findings Report, Boeing RFI Subarea Big South, Santa Susana Field Laboratory, Ventura County, California? PCA: 22120 Site Code-WP: 300232-48 The Human and Ecological Risk Of?ce (HERO) of the Department of Toxic Substances Control (DTSC) reviewed the Human Health Risk Assessment (Appendix D) component of the ?Human Health and Ecological Risk Assessment for Surface Water in the Southwest Drainage of Boeing RFI Subarea Big South? (Appendix D), dated June, 2015. Appendix presents the Human Health Risk Assessment (HHRA) associated with potential surface water exposures to a theoretical future recreator visiting the 59 South area, in particular, the unaf?liated area containing three seeps FDP-BQD and FDP-890pool) located in the Southwest Drainage in the undeveloped land bordering Area on the south. HERO comments resulting from review of the ERA will be presented under separate cover. DRAFT comments on review of the HHRA are provided below. Background Boeing Co. recently submitted Data Summary and Findings Reports for the following four RCRA Facility Investigation Sites (RFI Sites), where all RFI Sites except the Environmental Effects Laboratory (EEL Site) are entirely located in Subarea 5(9- South of Administrative Area The EEL Site is located along the boundary line dividing Administrative Area (Boeing?s responsibility for cleanup) from Administrative Area IV (Department of Energy's responsibility for cleanup): 3} Printed on Recycled Paper Julie Lincoln Human Health Risk Assessment for the Surface HERO Comments on HHRA Page 2 of 4 Waters in Seeps Near Subarea 519 South at SSFL July 15, 2016 Systems Test Laboratory lV (STL-IV) Compound A Facility Area Sewage Treatment Plant (STP-3) Environmental Effects Laboratory (EEL) These RFI Sites were historically associated with industrial activities, and multiple chemical use areas have been identi?ed within each RFI Site. Also included were for two separate areas that were unaf?liated with these RFI Sites. The unaf?liated areas are located east and south of the southern?most RFI Site, the RFI Site. The southern-most unaf?liated area is located directly south and contiguous with Administrative Areas II, and IV. No industrial activities were performed in the unaf?liated areas, nor did they contain buildings. The purpose of the is to present data and information evaluated to identify sources, nature and extent, transport and fate of chemical and radiological contamination, and to assess potential risks to human health and the environment. This risk information will be used to identify cleanup areas during the Corrective Measures Study. The following comments address discrepancies found during review of the Human Health Risk Assessment (HHRA) for surface waters located in the southerly unaf?liated area bordering Area Ill. The HHRA quantitated health risks to a theoretical recreator, resulting from potential exposure to chemicals and radionuclides recently identi?ed in surface waters, ie, three seep areas. Because of the limited water volume in these seeps, the sole exposure pathway evaluated was dermal contact. General Comments from Review of the 519 South Surface Water HHRA General comments on the Sig-South Surface Water HHRA were as follows below. Speci?c Comments on Appendix of the DSFR Human Health and Ecological Risk Assessment for Surface Water in the Southwest Drainage of Boeing RFI Subarea 51'9 South: (1) Page 0-2, Section 4.2 (Human Health Risk Assessmen?Human Exposure Assessment): The last paragraph in this section identi?es three seeps (FOP-831, FDR-890 and that constitute surface waters in the 519 South Subarea where a recreator might contact soluble or suspended contaminants. The last sentence states that no radionuclide data were reported as detected at these seeps and therefore no ROPCs were identi?ed. Yet Table D-2 (Location-Speci?c Surface Water Concentrations) shows that maximal concentrations of gross alpha (46 pCilL) and gross beta (37.8 radiation were detected in seepage water from FDR-831, but these detections were not attributed to speci?c radioisotopes. Hence, the above statement in Section 4.2 should be revised. HERO reviewed the ?lterable dataset for surface waters associated with the above three seeps provided by CH2M Hill. According to CHZM Hill representatives, this dataset was provided in the DSFR for ?Areas Unaf?liated with Sites,? but was not included on the CD accompanying the DSFR for Julie Lincoln Human Health Risk Assessment forthe Surface HERD Comments on HHRA Page 3 of4 Waters in Seeps Near Subarea 5ft! South at SSFL July 15, 2016 this ?Boeing RFI Subarea South? report. It should be added to the CD for this report. We con?rmed that there were no radioisotopes speci?cally identi?ed in samples collected from the above three seeps. The only detected radionuclide data in the ?lterable dataset were the above results (ie, "gross alpha? and ?gross beta?), all from seep samples collected July 9, 2009. According to CHZM Hill, no additional radiological data for the three above seeps were available. Please explain these ?gross alpha? and ?gross beta? results, why radionuclides were not speciated during this analysis, and why additional follow-up samples were not collected. Specific Comments on Appendix Tables: (2) Table D-2 (Location-Speci?c Surface Water Concentrations): This table should specify that the surface water analyte concentrations listed represent the maximum concentrations detected over the last 3 years of available data for each chemical in each of the three seeps, and that these are used in the HHRA as Exposure Point Concentrations. The footnote stating the following should be ed this chemical was not reported as detected over the last 3 years of available data (or was not a target analyte).? it is ambiguous because if it was not detected over the last 3 years, then this designation is within the scope of what you are listing. But, if it was not a target analyte, the question that arises is ?why wasn?t it?? This is especially applicable to the apparent lack of detections of radioisotopes in seeps FDP-890 and (3) Table D-3 (Summary of Risk and Hazard Estimates for Maximum Risk Location at Boeing RFI Subarea 5l9 South: Recreational Scenario) and Tables 0-4 Through D-B (Risk And Hazard Estimate for Exposure to Surface Water Locations: FOP-890 and HERO spot-checked the cancer risk and non-cancer hazard calculations for each of these three seep areas and found that they were correctly calculated. A typographical error on Table lists the HQ for TCE at FOP-890 as 0.7 when it should be 0.5 (per Table D-5). This error is reproduced in the text in Section 4.1.1 (Health Risk Characterizatioanuture Recreational Exposure Scenario). Speci?c Comments on Attachment Tables: (4) Attachment D-1 (Site Speci?c Recreational Risk-Based Concentrations for Surface Water): HERO spot-checked three surface water screening levels (SLs) for major riskfhazard drivers in surface water, ie, trichloroethylene and vinyl chloride. Only dermal exposures were considered, and this limitation was appropriate for seeps containing minimal standing water. PM: Julie Lincoln Human Health Risk Assessment for the Surface HERO Comments on HHRA Page 4 of 4 Waters in Seeps Near Subarea 54'9 South at SSFL July 15, 2016 The carcinogenic and non-carcinogenic SLs listed for these compounds on Attachment D-1 were correctly calculated. Conclusions and Recommendations: HERO is requesting an explanation of the gross alpha and gross beta radiation detections from seep resulting from a 2009 sampling event, and why follow-up sampling was not conducted. And, minor explanatory edits are recommended for Table D-2 per Comment Reviewed by: _x . - .4 - Jim Polisini, a, $33 Supervising Toxicologist . . i ?33 Human and Ecological Risk if" ?r L- - k- \t Department of Toxic Substances Control Barbara Lee Matthew Rodriquez Director Edmund G. Brown Jr. Secretary for Governor Environmental Protection 9211 Oakdale Amienue Chatsworth, California 91311 TO: Julie Lincoln, PE Brown?elds and Environmental Restoration Program DTSC?Sacramento FROM: Donald V. Greenlee, DABT My Staff Toxicologist DATE: April 6, 2016; revised July 29, 2016 SUBJECT: HERO Comments on the ?Human Health Risk Assessment for the Compound A Facility RFI Site? (Appendix E1), contained in the Facility Investigation Data Summary and Findings Report, Compound A Facility RFI Site, Volume I, Boeing RFI Subarea 5f9 South, Santa Susana Field Laboratory, Ventura County, California" PCA: 22120 Site Code-WP: 300232-48 The Human and Ecological Risk Of?ce (HERO) of the Department of Toxic Substances Control (DTSC) reviewed the Human Health Risk Assessment (Section 5 and Appendix E1) component of the Facility Investigation Data Summary and Findings Report, Compound A Facility RFI Site, Volume 1, Boeing RFI Subarea 5/9 South, Santa Susana Field Laboratory, Ventura County, California? (herein referred to as ?Cmpd-A dated June, 2015. Section 5 presents a summary of the HHRA and Ecological Risk Assessment (ERA) ?ndings, where the main body of the HHRA and tabulated risk calculations are presented in electronic form as Appendix E1 of the RCRA Facility Investigation Data Summary and Findings Report (DSFR). HERO comments resulting from review of the ERA will be presented under separate cover. As part of the review of the HHRA for the Environmental Effects Laboratory RFI Site (EEL RFI Site), HERO reviewed ?Appendix C, Human Health Risk Assessment for the Hypothetical Future Domestic Use of Chatsworth Formation Groundwater in Boeing RFI Subarea 5/9 South? of the Facility Investigation Data Summary and Findings Report, Boeing RFI Subarea 5/9 South, Santa Susana Field Laboratory, Ventura County, California," (herein referred to as the SIS-South (3W HHRA). comments on the Cmpd-A RFI Site HHRA regarding risk characterization of groundwater as described in Appendix are essentially the same as those for the EEL RFI Site, and are included here to ensure that this review was comprehensive. The Printed on Recycled Paper PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 2 of 13 RFI Site at SSFL April 6, 2016; revised July 29, 201E Cmpd-A HHRA was prepared by CHZM Hill for the Boeing Company. comments on review of this HHRA are provided below. Background Boeing Co recently submitted Data Summary and Findings Reports for the following four RCRA Facility Investigation Sites (RFI Sites), where all RFI Sites except the Environmental Effects Laboratory (EEL Site) are entirely located in Subarea 5/9- South of Administrative Area The EEL Site is located along the boundary line dividing Administrative Area Ill (Boeing?s responsibility for cleanup) from Administrative Area IV (Department of Energy?s responsibility for cleanup): Systems Test Laboratory IV (STL-IV) Compound A Facility Area Ill Sewage Treatment Plant Environmental Effects Laboratory (EEL) These RFI Sites were historically associated with industrial activities, and multiple chemical use areas have been identi?ed within each RFI Site. Also included were for two separate areas that were unaf?liated with these RFI Sites. The unaf?liated areas are located east and south of the southern-most RFI Site, the RFI Site. The southern-most unaffiliated area is located directly south and contiguous with Administrative Areas II, and IV. No industrial activities were performed in the unaf?liated areas, nor did they contain buildings. The purpose of the is to present data and information evaluated to identify sources, nature and extent, transport and fate of chemical and radiological contamination, and to assess potential risks to human health and the environment. This risk information will be used to identify cleanup areas during the Corrective Measures Study. The following comments address discrepancies found during HERO's review of the Human Health Risk Assessment (HHRA) for the Cmpd-A RFI Site. The HHRA quantitated health risks to a theoretical Suburban Resident and, at Boeing?s option, to a Recreator, resulting from potential exposure to chemicals and radionuclides currently existing at this RFI Site. Exposure pathways included in the cumulative Site health risks were those associated with chemicallradionuclides identified in Site soils, dust and vapors, and in Subarea SIS?South groundwater (as determined from the groundwater well presenting the greatest health risk within this subarea), is, health risks in the Cmpd-A HHRA and in the 5i'9-South GW HHRA: Chemicalsfradionuclides Exposure Chemicalsiradionuclides Exposure Pathways - Soil, Dust, Vapors Pathways - Groundwater Soil ingestion Ingestion of impacted groundwater Dermal absorption Dermal absorption during showering Ambient dustlvapor inhalation with impacted groundwater Indoor air vapor intrusion from soil gas Inhalation of vapors during showering with impacted groundwater PM: Julie Lincoln Human Health Risk AssesSment for the Compound-A HERO Comments on HHRA Page 3 of 13 RFI Site at SSFL April 5. 2015; revised July 29, 2016 In accordance with the Standardized Risk Assessment Methodology-Revision 2, Addendum Addendum), health risks associated with consumption of fruits and vegetables grown in an on-Site backyard garden were quantified separately but were not summed with the above health risks. General Comments from Review of the Cmpd-A HHRA HERO comments made here for the SIS-South GW HHRA are applicable to each RFI- Site in the 5(9-South Subarea because a representative well point (HAR-18), presenting the greatest health risk out of 10 groundwater wells in this Subarea, was used to characterize groundwater health risks at each RFI Site. HERO did not observe any obvious over-arching conceptual errors in the Cmpd-A HHRA or the Sig-South Subarea Groundwater HHRA, so only specific comments shown below were notable. HERO requests responses to the following comments: Specific Comments on DSFR Section 5 Risk Assessment Summary of the Cmpd-A HHRA: (1) Page 5-2, Section 5.1.3.1 (Estimated Risks HazardsiHypothetical Suburban Residential ScenarioiDirect Contact with Soil): A summary of the risk assessment results is presented in this paragraph, but no reference is made to Table 5-1 which summarizes these results?please add this reference in the text. The third sentence mentions that a statistical comparison between Site and Background arsenic levels indicates ?no signi?cant difference? between the two data distributions. It should clarify that there were no significant statistical differences between background (24.2 mgr?kg As and both Site arsenic datasets, ie, between 0-2 ft (76.9 mgikg max; 110 As detections out of 120 samples) and 0-10 ft (107 mgikg max; 162 As detections out of 175 samples) according to the Wilcoxon Rank Sum test. Also, please add a reference to Appendix E1, Table E1-1 (Summary Statistics and Exposure Point Concentrations for Chemicals of Potential Concern). Finally, based on the higher detected concentrations of arsenic in both above datasets, please add a comment con?rming the potential existence of arsenic ?hot spots,? as further con?rmed in Attachment 1, Table 8 (Evaluation of Potential for Hot Spots in Soil (9-10 ft bgs)) to Appendix E1. (2) Page 5-2, Section 5.1.3.1 (Estimated Risks 8: HazardsiHypothetical Suburban Residential ScenarioiExposure to Radionuclides in Soil): This paragraph summarizes the cancer risk results for the Suburban Resident due to potential exposure to Site-related radionuclides. In accordance with the SRAM- Rev 2 Addendum, please add these risk results to the chemical risks shown in Table 5?1. PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 4 of 13 RFI Site at SSFL April 6, 2016; reviSed July 29, 2016 (3) l4) (5) The last sentence states that Uranium-238 is not considered to be a Radionuclide 0f Concern (ROC) because detected levels are consistent with background levels, the incremental ELCR is ?relatively low.? and due to the conservative nature of radionuclide RBSL calculations. The ?rst paragraph under Section 5.1.4 (Summary of Findings) later provides a working definition of 0003 and ROCs which ?are those unacceptable risk and, therefore are retained for further evaluation during the For the Suburban Residential exposure, cancer risks exceeding are unacceptable for unrestricted land use. Further, selection of U-238 as a COPC indicated that Site levels were distinct from background levels (Attachment 1, Table 3 (Comparison of Maximum radionuclide Concentrations in Site Soil with Background Levels)). While HERO agrees that the Site U-238 exposure point concentration (EPC) is close to the Background U-238 EPC, and the associated incremental risk (2E-6) is low, we see no justi?cation for concluding that U-238 is not an ROC. Please remove this sentence. Page 5-3, Section 5.1.3.2 (Future Recreator ScenariolDirect Contact with Soil): This two sentence paragraph summarizes chemical risk results to the Recreator. Please add a reference to the accompanying Table 5-1 (Human Health Risk Estimates) which summarizes these results. Page 5-3, Section 5.1.3.2 (Future Recreator ScenariofExposure to Radionuclides in Soil): This two sentence paragraph summarizes potential radionuclide risk results to the Recreator. Please add the results from Table E1-4 (Radiological Risk Summary by Exposure Scenario) to the summarized chemical risks to the Recreator and include all on Table 5-1, or create separate risk summary tables for the Suburban Resident and for the Recreator. 2 Addendum specifies that chemical and radiological risk results are additive. Page 5-3, Section 5.1.4 (Summary of Findings): The ?rst paragraph states that ?No ROCs are identi?ed for soil at the Compound A Facility site." Please remove this sentence and provide a summary bullet point addressing the incremental cancer risk (2E-5) to the Suburban Resident associated with exposure to radionuclides in soil and groundwater at the Compound A Site that is consistent with risk results summarized in Table E1-4 (Radiological Risk Summary by Exposure Scenario; ie. incremental cancer risks of 2E-6 by direct contact with soil, and 2E-5 for domestic use of shallow groundwater). To be consistent with Table E1-3 (Chemical Risk Summary by Exposure Scenario) and Table E1-4, the second sentence should state that ?For this HHRA, 0005 are identi?ed for soil, soil vapor and groundwater.? Primary contributors to incremental ELCR and HI estimates should include those listed in Table E1-3 and E1-4 under the ?Primary Contributors to Cancer Risk? and ?Primary Contributors to Hazard Index? heading. PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 5 of 13 RFI Site at SSFL April 6. 2015; revised July 29, 2015 Speci?c Comments on Compound A HHRA, Appendix E1: (7) (3) (9) Page 2, Section 4.1 (Data Used for the Evaluation and Selection Criteria): This section outlines steps followed to generate the ?nal risk assessment data set. Point number 2 in this section states: "Soil and soil vapor samples collected from depths greater than 10 ft were removed from the data set, per the SRAM Rev. 2 Addendum." HERO reviewed the SRAM Rev. 2 Addendum and did not ?nd that it provided for limiting the soil vapor VOC data set to soil vapor measurements made from 0-10 ft bgs. Please provide the correct reference for this statement. In addition, point number 4 states: ?The shallowest soil vapor data from between 5 to 10 ft were used for each sample point." This statement requires a methodology reference, which appears to be Appendix of the Comprehensive Data Quality Objectives, RCRA Facility Investigation, SSFL, Ventura County, CA, March 2013. Please add this reference as a footnote. Also, please address how soil vapor modeling will be addressed if overlying soils have been excavated to less than a 5 ft soil cover to remove other contaminants. Page 6, Section 8.1.1.1 (Human Health Risk CharacterizationlDirect Contact with Soil): The third paragraph from the top of page 6 lists an Exposure Point Concentration for background lead of 15.9 mgikg, but this value is not presented in the DSFR for Compound?A. Please provide a reference to substantiate the background lead EPC. Page 6, Section 8.1.1.1 (Human Health Risk CharacterizationiExposure to Radionuclides in Soil): The second paragraph of this section should state that the incremental Estimated Lifetime Cancer Risks (ELCR) to the Suburban Resident (2E-6) and the Site Recreator associated with potential exposure to radioisotOpes identi?ed in on-Site soils, were low. Nevertheless, these cancer risks were added to the incremental chemical risks for the Site, consistent with requirements of SRAM?Revision 2 Addendum. These incremental radiological cancer risks should also be shown on a cancerihazard summary table that applies to the entire Site, such as a revised Table E1-3 (Chemical Risk Summary by Exposure Scenario), so that the reader can clearly see that they have been added. Page 7, Section 8.1.1.4 (Groundwater Use Pathway): The second to last paragraph in this section states that only well point RD-55A, out of 10 groundwater wells in Subarea SIS-South, contained lead (Exposure Point Concentration 40.1 uglL) that exceeded the federal MCL of 15 ugfL. [It would be informative to mention that this is also the California HERO understands that well point HAR-13 was selected to be representative of Subarea SIS-South groundwater because chemical EPCs presented the PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERD Comments on HHRA Page 6 of 13 Site at SSFL April 6, 2015; revised July 29, 2016 (1 0} (11) (12) greatest health risk in this well. However, considering the low detected lead level in HAR-18 (2.9 uglL), the lack of an as yet unde?ned ?No Adverse Effect Level? for lead toxicity on childhood IQ, and, that if groundwater was actually used for bene?cial purposes, it would likely be drawn from the nearest available groundwater location, one of which could be well point RD-55A, please either explain why groundwater at well point RD-55A should not be considered the equivalent of a lead ?hot-spot,? or mention how lead at this well point will be dealt with in the CMS phase. Page 8, Section 3.1.2.1 (Direct Contact [of Recreator] with Soil): Referring to Table E1-7 (Chemical-speci?c Incremental Risk and Hazard Estimates for Soil), the second paragraph states: ?For the direct soil contact pathway, there is no incremental risk over background.? However, according to this table, the cumulative incremental cancer risk is 4.7E-7. Thus, the above statement should be changed to re?ect this. The third paragraph states that the EPC for lead in the 0?2 ft soil layer is 70.8 and the background EPC is 15.9 mgikg. These statements should refer the reader to Table E14 and MWH's table of 95% UCLs for background analytes, respectively. Page 3, Section 8.1.2.1 (Direct Contact [of Recreator] with to ROPCs in Soil): In the first paragraph, please explain why incremental cancer risks were not calculated for Site radioisotopes as they were for chemicals. Currently, it is left to the reader to guess that this was a short-cut taken because the total Site radiological cancer risk (4E-8) was well below Point of Departure of 1E-6. Yet, 2 Addendum requires summation of chemical and radiological cancer risks. To be consistent with this, it seems that a summary table should be generated showing that both the chemical and radiological incremental risks are added. Table E1-2 (Summary Statistics and Exposure Point Concentrations (EPCs) for Radionuclides of Potential Concern): This table lists radioisotopes of potential concern detected at the Cmpd?A Site, descriptive statistics for those radioisotopes that were detected (such as minimum, maximum, mean and standard deviation), and summarizes whether each was selectedfnot selected as a Radioisotope of Potential Concern (ROPC) and if not selected as an ROPC, the reason for exclusion. The details of the ROPC selection process are presented in Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels) where the maximum background concentration for each isotope is compared against either 95% UTLs or Background Threshold Values (BTVs), for those isotopes with an insuf?cient number of detections in the Radiological Background Study Report (2011) to evaluate statistically. PM: Julie Lincoln Human Health Risk Assessment for the Compound?A HERO Comments on HHRA Page 7? of13 RFI Site at SSFL April 6, 2616; revised July 29. 2616 Footnote-c incorrectly cites the Chemical Background Study as the source of values for background radionuclides, when it should cite the EPA's Radiological Background Study Report. Please make this correction. (13) Table E1-3 (Chemical Risk Summary by Exposure Scenario): This table (14) summarizes cancer risks and HI values for the Suburban Residential and Recreator exposure scenarios that are derived on Table E1-5 (Risk and Hazard Estimates for Exposure to Soil (0-10 ft bgs), Table E1-6 (Risk and Hazard Estimate for Exposure to Background Soil), Table E1-7 (Chemical-Speci?c lncremental Risk and Hazard Estimates for Soil), Table E1-11 (Risk and Hazard Estimates for Exposure to Soil Vapor), and Table E1-12 (Risk and Hazard Estimates for Exposure to Chatsworth Groundwater). To be compliant with the 2 Addendum, the incremental soil radiological cancer risk (2E-6) and shallow groundwater radiological risk (2E-5) results (Table (Radiological Risk Summary by Exposure Scenario? should be added to the chemical cancer risks provided in Table to obtain the ?nal multimedia cancer risk at the Site. Finally, the column labeled ?Primary Contributors to Hazard Index? corresponding with the row labeled ?Background Soil Direct Contact" should list arsenic 42%) and thallium 42%) because the total . Background Hl exceeds 1.0. Table E1 -6 (Risk and Hazard Estimates for Exposure to Background Sell): The heading for column 2 entitled ?Exposure Point Concentration (mg!kg)? should be footnoted to indicate that these values represent 95% UCL values from the Chemical Background Study datasets, and that these values can be found partially on Table 5 of statistical evaluation of the chemical background data (DTSC URS, 2012), and the remainder on "Background Threshold Values Using Combined Chemical Background Data (DTSC, 2012b)." According to the June 2016 version of HERO Note 3, the non-carcinogenic Soil Screening Level (SSL) for cadmium exposure to the Suburban Resident is 5.2 (DTSC, 2016). The soil RBSL cited in Table E1-6 lists a value of 4.6 based on an earlier version of HERO Note 3?please update this value. Also make corrections to the non-carcinogenic Garden and Recreator exposure scenarios soil cadmium since these are based on the 4.6 value assuming exposure to a composite adult. (15) Table E1-7 (Chemical-Specific Incremental Risk and Hazard Estimates for Soil): For the suburban residential and recreator receptors scenarios, this table summarizes for each chemical: (1) total cancer risks and hazard quotients; (2) background cancer risks and hazard quotients; and (3) incremental cancer risks and hazard quotients. On this table, please provide PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 8 of 13 RFI Site at SSFL April B. 2016; revised July 29, 2015 the summed cancer risks and hazard indices for the Total Site, Background and Incremental health risks for both the Suburban Resident and Recreator chemical exposure scenarios. Check to ensure that these values are the same as those on Table E?l-3 (Chemical Risk Summary by Exposure Scenario). This would facilitate review of these ?nal health risk numbers. (16) Table E1-8 (Risk Estimates for Exposure to Soil Radionuclides (O to 2 feet bgs): This table summarizes Exposure Point Concentrations (EPCs) for ROPCs detected from 0-2 ft bgs, carcinogenic radioisotope (RAD) Risk-Based Screening Levels previously calculated for the Suburban Residential, Suburban Residential Garden, and Recreational Exposure Scenarios, and the carcinogenic human health risks calculated using these for each exposure scenario. The footnote to Table stating that the radiological were derived per an email from Mike Bowen'Boeing to Roger Paulson, dated January 14, 2015 is minimally informative and lacks transparency. Please consider re-stating this? as follows: ?Soil Radiological for a Resident were calculated using Preliminary Remediation Goals (PRG) for Radionuclides Calculator (available at: search}, where default input values were used except for the following Site-specific inputs: Eagle Value j_3? .. ED;iassassinateage?satm. . i251.-. lFSr?adj (age-adjusted soil ingestion factor- residentimg, IFAr-adi (assidiustessetmajaion facts-Eider}. r113. .. lRFr?a (fruit consumption rate; residen?dultlgiday?__ . 3773_ rate - ?3145? child) 34-9 IFVr-sdi (age-adjusted vesseble ingestianfactgr: resident) 39.06.7319 .. IFFr?auiegs-aqrusted fruit maestro agar QPFrioontamisatsd plantfrastioni unitlsis__ . a L1 This same comment also applies to Table E1-9 (Risk Estimates for Exposure to Background Soil Radionuclides) and Attachment 1, Table 7 (Risk Estimates for Exposure to Soil Radionuclides (0-10 it bgs). Please incorporate the above changes into both Tables and Also, add a footnote referencing that the Exposure Point Concentrations in Table E1-8 are all maximum values as shown in Table E1-2. Add a similar footnote to Table E1-9 referencing that EPCs are 95% UCL values and cite an applicable reference. PM: Julie Lincoln Human Health Risk Assessment forthe Compound-A Page 9 of 13 April 6. 2016; revised July 29, 2016 Site at SSFL HERO Comments on HHRA (17) Table E1-10 (Radionuclide-specific Incremental Risk Estimates for Soil): To be consistent with Comment #15 (Table please show the summed cancer risks and hazard indices for the Total Site, Background and Incremental health risks for both the Suburban Resident and Recreator exposure scenarios at the bottom of Table E1-10. (18) Table E1-11 (Risk and Hazard Estimates for Exposure to Soil Vapor): This table summarizes Exposure Point Concentrations (EPCs) and calculates cancer risks and hazard quotients for potential indoor inhalation exposures to VOCs detected in soil vapor at the Cmpd-A Site. Carcinogenic and non- carcinogenic soil vapor were used to calculate these health risks in accordance with the Sum of Fractions approach (MWH. 2014). HERO noted that several toxicity factors have been updated since the soil vapor were determined (see HERO Note 3 (June, 2016)). Thus during the CMS phase. in accordance with Boeing's agreement with DTSC, the carcinogenic and non-carcinogenic vapor inhalation will need to be recalculated along with the associated cancer risks and non?cancer hazard quotients for at least the following compounds (toxicity values for all compounds should be checked): Carcinogenic RBSL-SV (ugim?) Non-Carcinogenic RBSL-SV (ugima) Table E1 -11 Updated Table E1 -11 Updated -- -- Benzene 83.9 97 cis-1,2-DCE -- 6.26 2.09 NC Tetrachloroethvlene 9.36E-I-3 Trichloroethylene NC Xylenes. total -- Abbreviations: 1,1idichloroethylene; NC not calculated; RBSL-SV soil vapor risk-based screening level. (19) Table E1-12 (Risk and Hazard Estimates for Exposure to Chatsworth Groundwater (Domestic use at Well (Attachment Ci) below which refers to corrections needed for Table E1-12. HAR-18): See comment #27 (20) Table E1-13 (Risk Estimates for Exposure to Radionuclides in Chatsworth Groundwater (Domestic use at Well HAR-18): Footnote-A references the source of the groundwater radionuclide as an email communication between Boeing and DTSC, dated January 14, 2015. This reference should enable the reader to directly lockup the groundwater radionuclide in order to verify their accuracy in this table. Please modify this footnote to achieve this goal. (21) Figure E1-1 (Conceptual Exposure Model for Potential Human Receptors): This figure shows footnote-C referring to groundwater exposures, but the PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 10 of 13 RFI Site at SSFL April 6, 2016; revised July 29, 2016 footnote-C designation is not included in the groundwater exposure routes illustrated in the ?gure-please include it. The following comments pertain to Attachments to Appendix (Human Health and Ecological Risk Assessment Findings for Cmpd-A RFI Site). (22) Attachment 1, Table 2 (Comparison of Maximum Chemical Concentrations in Site Soil with Background Levels): In the two columns (one for the 0-2 ft dataset, the other for the 0-10 ft dataset) labeled ?Considered it would aid clarity and speed review if a ?yesfno" answer was also supplied in addition to the listed result ?See background statistics." ?See background statistics? should also be footnoted to refer the reader to Attachment 1, Table 4 (Results of Background Statistical Comparisons for Soil). Also, footnote-a is incomplete. This footnote refers the reader to the source of the ?Background Concentrations," for which there are two sources: a Table 5 of the Chemical Study Background Report; and . ?Background Threshold Values [table] Using Combined Chemical Background Data,? in ?Combined-Data Background Threshold Values and Methodology Narrative, Chemical Background Study,? DTSC, December 21, 2012. Footnote-a should also identify the ?Background Concentrations" as being values. (23) Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels): Footnote-a in Table 3 should indicate that the heading, ?Background Concentration," refers to concentrations. Also, the heading ?Considered should be changed to ?Considered (24) Attachment 1, Table 5 (Aroclor to PCB Congener Extrapolation): Please correct the de?nition of in the table key to ?extrapolation factor? instead of ?extraction factor." (25) Attachment 1, Table 6 (Risk and Hazard Estimates for Exposure to Soil (0-2 ft bgs): Please make corrections to the soil for cadmium for all three exposure scenarios (resident, garden and recreator) as discussed in comment #14 for Table E1-6. (26) Attachment 1, Table 7 (Risk Estimates for Exposure to Soil Radionuclides (0-10 feet bgs): Footnote-a should more accurately identify the source of all radionuclide Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Site at SSFL PM: Julie Lincoln Page 11 of 13 April 6. 2016; revised July 28. 2016 The following comments pertain to Appendix of the Sig-South DSFR (Human Health risk Assessment for Hypothetical Future Domestic Use of Chatsworth Formation Groundwater in Boeing RFI Subarea 519 South, Ventura County, California): This appendix provides an evaluation of the health risks associated with beneficial use of area groundwater that generally underlies Subarea Sig-South. The Conceptual Site Model envisions groundwater exposures to the Suburban Resident occurring through ingestion, dermal absorption and inhalation of vapors during showering. Ten groundwater wells are monitored in this region. As calculated in Tables (3-4 to 0-14 in Appendix C, the well point containing groundwater that presents the maximum risk and hazard is HAR-18 (associated with the Systems Test Laboratory IV (STL-IV) RFI Site). Chemical and radiological groundwater data from HAR-18 is used to characterize health risks for each of the RFI Sites located in Subarea SIB-South. HERO comments on Appendix are included below. (27) Attachment C-1 (Site-Speci?c Suburban Residential Risk-Based Concentrations for Tap Water): HERO sought to reproduce the Tap Water Screening Levels (SLs) listed in this table for the four riskihazard driving chemicals associated with the beneficial use of Site groundwater (ie, from HAR-18) at the Cmpd-A Site. As stated in Section 8.1.1.4 of the Cmpd-A HHRA (Groundwater Use Pathway), these compounds were: dichloroethylene, N-nitrosodimethyiamine, trichloroethylene and vinyl chloride. We used the RSL Calculator, accessed via RSL table website, and inputs specified in Attachment C-1 of the Subarea SIS?South DSFR to calculate groundwater SLs IX, June 2015). Except for slight differences in the non?carcinogenic SL for (11.4 ugiL HERO vs 10.4 ugiL CHZM) and in the carcinogenic SL for vinyl chloride (1.79E-2 ug/L HERO vs 1.36E-2 ugiL CHZM), HERO veri?ed the carcinogenic and non-carcinogenic SLs listed in Table E1-12 of Appendix E1 in the Cmpd-A HHRA for trichloroethylene and vinyl chloride. The SLs for N-nitrosodimethylamine appear to be in error because this compound was incorrectly identified in Attachment 0-1 as a ?non-V00.? Thus, the inhalation SL corresponding with VOC inhalation during showering was not calculated. Differences between SLs for N-nitrosodimethylamine listed in Attachment 0?1 with those calculated by HERO are shown below: Compound Source Carcinogenic SLs Non-Carcinogenic SLs (ugiL) (uaiLi Inhalation Total Inhalation Total SL SLG SL 3an N-nitrosodimethyiamine Attachment - 1.51 E-3 -- HERO 1.37E-4 8.34E-2 5.48E-2 risk-based screening levels for tapwater exposure. ?Totat for carcinogenic effects (Total SLC) and for non-carcinogenic effects (Total San) include the ingestion, dermal absorption and vapor inhalation exposure pathways. PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 12 of 13 RFI Site at SSFL April 6, 2016; revised July 29, 2016 HERO reviewed all inputs to columns in Attachment (3-1 labeled ?Mutagen?? and and found that all mutagens were correctly identi?ed, but that the following additional ?ve compounds were misidentified as ?non-V003": 1 1,4-Dioxane Methyl hydrazine Formaldehyde lsopropanol Inhalation SLs were not provided for any of these compounds. Please make appropriate corrections to SLs in Attachment C-1 of DSFR for Subarea 51'9- South and to RBCs, cancer risks and hazard quotients calculated in Table E1-12 of the Cmpd-A HHRA. The minor changes in SLs for cis-1,2-DCE and vinyl chloride were different from our initial SL calculations for the EEL DSFR HHRA, and may be associated with updates in toxicity values on the EPA Region IX RSL table. Thus, it seems appropriate to recalculate SLs after the ?nal update in toxicity values. Finally, the de?nition of a ?volatile compound," as stated in 2 Addendum, should be updated to coincide with new de?nition of a volatile compound. Conclusions and Recommendations: HERO recommends that corrections outlined in Speci?c Comments #1?27 be made and the revised Cmpd?A HHRA and SIS-South GW HHRA be re?submitted to DTSC. Reviewed by: . 2g Jim Polisini,Ph.D. ,1 Supervising Toxicologist 3! Human and Ecological Risk Of?ce ?v REFERENCES DTSC and URS Corp, ?Chemical Soil Background Study Report.? June 8, 2012a. Available at: Susana Field Lab/ssfl document li DTSC, ?Cover Sheet to: Combined-Data Background Threshold Values and Methodology Narrative, Chemical Soil Background Study." December 21, 2012b. DTSC, HHRA Note Number: 3, DTSC-modi?ed Screening Levels June, 2016. Available at: MWH, ?Final Standardized Risk Assessment Methodology Revision 2 Addendum, Santa Susana Field Laboratory, Ventura County, August 2014. PM: Julie Lincoln Human Health Risk Assessment for the Compound-A HERO Comments on HHRA Page 13 of 13 RFI Site at SSFL April 6. 2016; revised Julyr 29, 2015 1X, ?Regional Screening Levels (Formerly Last updated June 2015. Available at: 1X, ?Final Radiological Background Study Report, Santa Susana Field Laboratory, Ventura County, California.? October, 2011. (1.1 ?r i H. - a Department of Toxic Substances Control Barbara Lee Matthew Rodriquez Director Edmund G. Brown Jr. Secretary for Governor Environmental Protection 921 1 Oakdale Av_enue Chatsworth, California 91311 TO: Julie Lincoln, P.E. Brownfields and Environmental Restoration Program DTSC-Saoramento FROM: Donald v. Greenlee, DABT 5" . Staff Toxicologist Zia":- a, DATE: October 7, 2015, Revised July 15, 2016 SUBJECT: HERO Comments on the ?Human Health Risk Assessment for the Environmental Effects Laboratory Site? (Appendix E1), contained in the Facility Investigation Data Summary and Findings Report, Environmental Effects Laboratory RFI Site, Boeing RFI Subarea Sig South, Santa Susana Field Laboratory, Ventura County, California? PCA: 22120 Site Code-WP: 300232-48 The Human and Ecological Risk Of?ce (HERO) of the Department of Toxic Substances Control (DTSC) reviewed the Human Health Risk Assessment (Section 5 and Appendix E1) component of the Facility investigation Data Summary and Findings Report, Environmental Effects Laboratory RFI Site, Boeing Subarea 5l'9 South, Santa Susana Field Laboratory, Ventura County, California? (herein referred to as dated June, 2015. Section 5 presents a summary of the HHRA and Ecological Risk Assessment (ERA) findings, where the main body of the HHRA and tabulated risk calculations are presented in Appendix E1. HERO comments resulting from review of the ERA will be presented under separate cover. HERO also reviewed ?Appendix C, Human Health Risk Assessment for the Hypothetical Future Domestic Use of Chatsworth Formation Groundwater in Boeing Subarea 519 South? of the Facility Investigation Data Summary and Findings Report, Boeing RFI Subarea 5f9 South, Santa Susana Field Laboratory, Ventura County, California,? (herein referred to as the Sig?South GW HHRA). Appendix presents the health risk calculations and discussion of results pertaining only to impacted groundwater located in Subarea Sig-South. Both the EEL HHRA and the Sig-South GW HHRA were prepared by CH2M Hill for the Boeing Company. HERO's comments on review of these two HHRAs are provided below. 3 Printed on Recycled Paper PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 2 of 11 Effects Laboratory RFI Site at SSFL July 15, 2015 Background Boeing Co recently submitted Data Summary and Findings Reports for the following four RCRA Facility Investigation Sites (RFI Sites), where all RFI Sites except the Environmental Effects Laboratory (EEL Site) are entirely located in Subarea 5r9- South of Administrative Area Ill. The EEL Site is located along the boundary line dividing Administrative Area (Boeing?s responsibility for cleanup) from Administrative Area IV (Department of Energy?s responsibility for cleanup): Systems Test Laboratory IV (STL-IV) Compound A Facility Area Ill Sewage Treatment Plant (STP-3) Environmental Effects Laboratory (EEL) These RFI Sites were historically associated with industrial activities, and multiple chemical use areas have been identified within each RFI Site. Also included were for two separate areas that were unaf?liated with these RFI Sites. The unaffiliated areas are located east and south of the southern-most RFI Site, the STL-IV RFI Site. The southern-most unaf?liated area is located directly south and contiguous with Administrative Areas II, and IV. No industrial activities were performed in the unaf?liated areas, nor did they contain buildings. The purpose of the is to present data and information evaluated to identify sources, nature and extent, transport and fate of chemical and radiological contamination, and to assess potential risks to human health and the environment. This risk information will be used to identify cleanup areas during the Corrective Measures Study. The following comments address discrepancies found during review of the Human Health Risk Assessment (HHRA) for the EEL RFI Site. The HHRA quantitated health risks to a theoretical Suburban Resident and, at Boeing?s option, to a Recreator, resulting from potential exposure to chemicals and radionuclides currently existing at this RFI Site. Exposure pathways included in the cumulative Site health risks were those associated with chemicalrradionuclides identi?ed in Site soils, dust and vapors, and in Subarea SIB-South groundwater (as determined from the groundwater well presenting the greatest health risk within this subarea), is, health risks in the EEL HHRA and in the SIS-South GW HHRA: Chemicalsrradionuclides Exposure Chemicalslradionuclides Exposure Pathways Soil, Dust. Vapors Pathways - Groundwater Soil ingestion Ingestion of impacted groundwater Denna] absorption Dermal absorption during showering Ambient dustfvapor inhalation with impacted groundwater Indoor air vapor intrusion from soil gas Inhalation of vapors during showering with impacted groundwater In accordance with the Standardized Risk Assessment Methodology-Revision 2, Addendum (SRAM-Z Addendum), health risks associated with consumption of fruits and vegetables grown in an on-Site backyard garden were quanti?ed but were not summed with the above health risks. PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 3 of 11 Effects Laboratory RFI Site at SSFL July 15. 2015 General Comments from Review of the EEL HHRA and the SIS-South GW HHRA HERO comments made here for the SIS-South GW HHRA are applicable to each RFI- Site in the SIS-South Subarea because a representative well point presenting the greatest health risk out of 10 groundwater wells in this Subarea, was used to characterize groundwater health risks at each Site. HERO did not observe any obvious over-arching conceptual errors in either the EEL HHRA or the SIS South GW HHRA, so only speci?c comments shown below were notable. HERO requests responses to the following comments: Speci?c Comments on Section 5 Risk Assessment Summary of the EEL HHRA: (1) Page 5-3, Section 5.1.4 (Summary of Findings): The ?rst paragraph states that Chemicalszadionuclides of Concern are those Chemicals of Potential Concern (COPCs)lRadioisotopes of Potential Concern (ROPCs) identi?ed during the HHRA as primary contributors posing unacceptable risk, and are therefore retained for further evaluation during the CMS. COCs were identi?ed in soil, but ROCs were not because the total cancer risks for the Suburban Resident (2E-7) and for the Recreator (4E-8) associated with potential exposure to ROPCs were less than point of departure (1 ES cancer risk). To be consistent with presentation of cumulative chemical and radioisotope cancer risks in the SRAlvl-Revision 2 Addendum, as described in Appendix I (Incremental Risk Calculation Methodology Technical Memo) and associated example Table 1, the sum of all incremental cancer risks should be presented in this section. This includes cancer risks associated with potential radioisotope exposures, even though the subtotal for ROPC cancer risks may be less than 1E-6. The fact that ROPCs are not risk drivers can be stated in the text. Specific Comments on EEL HHRA, Appendix E1: (2) Page 2, Section 4.1 (Data Used for the Evaluation and Selection Criteria): This section outlines steps followed to generate the ?nal risk assessment data set. Point number 2 in this section states: ?Soil and soil vapor samples collected from depths greater than 10 ft were removed from the data set, per the SRAM Rev. 2 Addendum." HERO reviewed the SRAM Rev. 2 Addendum and did not find that it provided for limiting the soil vapor VOC data set to soil vapor measurements made from 0-10 ft bgs. Please provide the correct reference for this statement. In addition, point number 4 states: ?The shallowest soil vapor data from between 5 to 10 ft were used for each sample point." This statement requires a methodology reference. which appears to be Appendix of the Comprehensive Data Quality Objectives, RCRA Facility Investigation, SSFL, Ventura County, CA, March 2013. Please add this reference as a footnote. PM: Julie Lincoln Page 4 of 11 Human Health Risk Assessment for the Environmental HERO Comments on HHRA Effects Laboratory RFI Site at SSFL July 15, 201B (3) (4) (5) Also, please address how soil vapor modeling will be addressed if overlying soils have been excavated to less than a 5 ft soil cover to remove other contaminants. Page 4, Section 6.1 (Exposure Point Concentrations): At the end of the ?rst paragraph, please add an explanation that in cases where there may have been only one or two detections out of several samples tested, that Exposure Point Concentrations (EPCs) were determined by the program. This program uses detected and undetected data to derive a 95% UCL. Page 6, Exposure to ROPCs in Soil: The second paragraph of this section should state that although the incremental Estimated Lifetime Cancer Risk (ELCR) associated with potential exposure to radioisotopes identi?ed on-Site was below point of departure, these cancer risks were added to the incremental chemical risks for the Site, consistent with requirements of SRAM- Revision 2 Addendum. These incremental cancer risks should also be shown on a table, such as a revised Table (Chemical Risk Summary by Exposure Scenario; see comment Page 6, Section 8.1.1.2 (Garden Use): in this section, several total cancer risk values and Hi values for health risk drivers shown in Table E1-5 are misquoted in the second and third paragraph text. They include: (6) Chemical Cancer Risk? Contribution HI Contribution Text Table Text Table Text Table Text Table Arsenic 96 97 52 70 7E-3 3ETotal for Site 486 363 incremental 377 255 ?Text? refers to values listed in Section 8.1.1.2 of the text; "Table? refers to values listed in Table Please make appropriate corrections. Page 7, Section 8.1.1.4 (Groundwater Use Pathway): The last paragraph under the heading ?Exposure to COPCs in Groundwater? states that only well point RD-55A, out of 1D groundwater wells in Subarea 5l9-South, contained lead (Exposure Point Concentration 40.1 ugiL) that exceeded the federal MCL of 15 uglL. [It would be informative to mention that this is also the California HERO understands that well point HAR-18 was selected to be representative of Subarea Sig?South groundwater because chemical EPCs presented the greatest health risk in this well. However, considering the low detected lead level in HAR-18 (2.9 ug/L), the lack of an as yet unde?ned ?No Adverse Effect Level? for lead toxicity on childhood IQ, and, that if groundwater was actually used for bene?cial purposes, it would likely be drawn from the nearest available groundwater location, one of which could be well point RD-55A, please either PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page Sof11 Effects Laboratory RFI Site at SSFL July 15, 2016 (7) (3) (9) explain why groundwater at well point RID-55A should not be considered the equivalent of a lead ?hot-spot," or mention how lead at this well point will be dealt with in the CMS phase. Page 3, Section 8.1.2.1 (Direct Contact [of Recreator] with SoillExposure to ROPCs in Soil): In the ?rst paragraph, please explain why incremental cancer risks were not calculated for Site radioisotopes as they were for chemicals. Currently, it is left to the reader to guess that this was a short-cut taken because the total Site radiological cancer risk (4E-8) was well below DTSC's Point of Departure of 1E-6. Table E1-2 (Summary Statistics and Exposure Point Concentrations (EPCs) for Radionuclides of Potential Concern): This table lists radioisotopes of potential concern detected at the EEL Site, descriptive statistics for those radioisotopes that were detected (such as minimum, maximum, mean and standard deviation), and summarizes whether each was selectedlnot selected as a Radioisotope of Potential Concern (ROPC) and if not selected as an ROPC, the reason for exclusion. The details of the ROPC selection process are presented in Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels) where the maximum background concentration for each isotope is compared against either 95195 UTLs or Background Threshold Values (BTVs), for those isotopes with an insuf?cient number of detections in the Radiological Background Study Report (2011) to evaluate statistically. Both Table E1-2 (footnote C) and Attachment 1, Table 3 (footnote A) incorrectly reference the Chemical Background Study Report (DTSC, 2012a) as the source of radioisotope background These footnotes should instead reference Appendix A in USEPA's Radiological Background Study Report (USEPA, 2011). Please make this correction to both tables. Table E1-3 (Chemical Risk Summary by Exposure Scenario): This table summarizes cancer risks and HI values for the Suburban Residential and Recreator exposure scenarios that are derived on Table E1-5. The row that summarizes health risks for the Suburban Residential receptor (?Multimedia Risk?) lists a total incremental cancer risk of 3E-2 and a total incremental HI of 320. The total incremental Hl appears to be underestimated, ie the value should be: [2 (direct contact with Site soil 0-2 ft bgs) 7 (indoor air vapor) 426 (domestic use of groundwater)] 435. Please explain how the value of 320 was derived, or make appropriate changes. Although the EEL Site radiological cancer risk was below point of departure, the calculated cancer risks from Table E1-4 should be included on Table E1-3 to be inclusive of all summed Site cancer risks. Also in this paragraph, contributions to the incremental Hl are misstated. TCDD (HQ 0.4) PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 6 of 11 Effects Laboratory RFI Site at SSFL July 15, 2016 contributes 33% to the incremental Hl (not and arsenic (HQ 0.7) contributes 57% to the incremental HI (not (10) Table E1-4 (Radiological Risk Summary by Exposure Scenario): Cancer risks listed in this table need correction or further explanation, see Comment #13. In addition, footnote-b in this table states that the background (radiological cancer) risk is based on data from the Final Chemical Soil Background Study Report, when it should state that the background risk is based on data from the Final Radiological Background Study Report (USEPA, Oct 2011). If background (radiological risk) is not going to be determined (see next paragraph), then this footnote should be removed altogether. Footnote-a should read are listed when radiological-speci?c risk instead of are listed when chemical-speci?c risk Finally, the table and associated footnote (ie, indicate that background exposure point concentrations were not computed for the ROPCs, but no reason is provided. Such a reason could be as simple as saying that Site radiological risks were below point of departure, and relative to the incremental chemical cancer risks, which exceeded EPA's risk management range (Table radiological risks were inconsequential. Nevertheless, these radiological risks are to be summed with the chemical risks (shown on Table E1-3) for this Site per SRAM-Revision 2, Appendix l. Please make this correction after the radiological cancer risk calculations are corrected (ie, corrections to Table E1-8). HERO noted that the uncertainty statement included under the ?Assessment Element? of ?Risk Characterization? in Table E1-12 (Human Health Risk Assessment Uncertainty Analysis) stated that chemical and radiological risks were reported separately because of ?the different uncertainties associated with each.? The reasoning behind this statement was unclear, and it was not further explained in the text. If CH2M Hill still believes that chemical and radiological risks should not be added, then the above statement should be explained, othenvise, HERO recommends eliminating it from Table (11) Table E1-6 (Risk and Hazard Estimates for Exposure to Background Soil): The heading for column 2 entitled ?Exposure Point Concentration should be footnoted to indicate that these values represent 95% UCL values from the Chemical Background Study datasets, and that these values can be found partially on Table 5 of statistical evaluation of the chemical background data (DTSC 8: URS, 2012), and the remainder on ?Background Threshold Values Using Combined Chemical Background Data (DTSC, 2012b)." [12) Table E1-7 (Chemical-Speci?c Incremental Risk and Hazard Estimates for Soil): For the suburban residential and recreator receptors scenarios, this table summarizes for each chemical: (1) total cancer risks and hazard PM: Julie Lincoln Human Health Risk Assessment forthe Environmental HERO Comments on HHRA Pagei'ofll Effects Laboratory RFI Site at SSFL July 15, zone (13) quotients; (2) background cancer risks and hazard quotients; and (3) incremental cancer risks and hazard quotients. On this table, please provide the summed cancer risks and hazard indices for the Total Site, Background and Incremental health risks for both the Suburban Resident and Recreator chemical exposure scenarios. Check to ensure that these values are the same as those on Table E1-3 (Chemical Risk Summary by Exposure Scenario). This would facilitate review of these ?nal health risk numbers. Table E1-8 (Risk Estimates for Exposure to Soil Radionuclides (0 to 2 feet bgs): This table summarizes Exposure Point Concentrations (EPCs) for ROPCs detected from 0-2 ft bgs, carcinogenic radioisotope (RAD) Risk-Based Screening Levels previously calculated. for the Suburban Residential, Suburban Residential Garden, and Recreational Exposure Scenarios, and the carcinogenic human health risks calculated using these for each exposure scenario. HERO used the EPA PRG Calculator to re-calculate for the Suburban Resident and Suburban Residential Garden scenarios. We found that the RAD calculated by the EPA PRG Calculator column labeled "External Exposure PRG (pCilg)? had been transposed into the column labeled ?Carcinogenic RBSL (pCifg)? in Table E1-8. Thus, the RAD were incorrect in Table E1-8, and because of this, the cancer risks calculated for each radioisotope were also expected to be in error. HERO also noted that RAD-RBSL calculations for the Residential scenario contained in Table 3 (Human Health Risk-based Screening Levels for Recently Detected Radionuclides in Soil) of Appendix E?l-Attachment 2 (Risk-Based Screening Levels for Recently Detected Chemicals and Radionuclides) were correct. Please check RBSL calculations for the Recreator scenario too, and substitute the correct for those in Table Then make appropriate corrections to all cancer risk estimates in Table E1-8 and the corresponding summary Table E1-4 (Radiological Risk Summary by Exposure Scenario). Finally, the footnote to Table E1-8 stating that the radiological were derived per an email from Mike BowenlBoeing to Roger Paulson, dated January 14, 2015 is minimally informative and lacks transparency. Please consider re- stating this?one possible way follows: ?Soil Radiological for a Resident were calculated using Preliminary Remediation Goals (PRG) for Radionuclides Calculator (available at: search), where default input values were used except for the following Site-specific inputs: Variable Value i {exposure duration - resident) yr i1260000 _I_F_Sr-adj (age-adjusted soil ingestion factor - resident) mg PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 3 of 11 Effects Laboratory RFI Site at SSFL July 15. 2015 soil inhalation i.R.F.r-a (fruitceneimetiqn rate :resident adult gear. . . 3773 (fruit consumption rate - resident child)_glday i ?ssisaitadult) side: 5 32ti?__ IRVH: (vegetable secession rate - resident child) stdav .. . .. . ..- IFVr-adl racer 33340355 lFFr-adj 9 (contaminated Plan! hasten). uni?es; Please incorporate the above changes into Table ?21 (14) Table E1-9 (Risk and Hazard Estimates for Exposure to Soil Vapor): This table summarizes Exposure Point Concentrations (EPCs) and calculates cancer risks and hazard quotients for potential indoor inhalation exposures to VOCs detected in soil vapor at the EEL Site. Carcinogenic and non- carcinogenlc soil vapor were used to calculate these health risks in accordance with the Sum of Fractions approach (MWH, 2014). HERO noted that several toxicity factors have been updated since the soil vapor were determined (see HERO Note 3 (June, 2016)). Thus during the CMS phase, in accordance with Boeing?s agreement with DTSC, the carcinogenic and non?carcinogenic vapor inhalation will need to be recalculated along with the associated cancer risks and non-cancer hazard quotients for the following compounds: VOC Carcinogenic RBSL-SV (uglma) Non-Carcinogenic RBSL-SV (uglm?) Table E1-9 Updated Table E1-9 Updated Benzene -- -- 6.26E-l-4 3.1 Tetrachloroethylene Xylenes. total -- -- (15) Table E1-10 (Risk and Hazard Estimates for Exposure to Chatsworth Groundwater (Domestic use at Well HAR-1B): which refers to corrections needed for Table E1-10. See comment #19 below (16) Figure E1-1 (Conceptual Exposure Model for Potential Human Receptors): This ?gure shows footnote-C referring to groundwater exposures, but the footnote-C designation is not included in the groundwater exposure routes illustrated in the ?gure-please include it. The following comments pertain to Attachments to Appendix (Human Health and Ecological Risk Assessment Findings for EEL RFI Site). (17) Attachment 1, Table 2 (Comparison of Maximum Chemical Concentrations in Site Soil with Background Levels): HERO checked the 95-95 UTLs listed for each chemical on Table 2 against the three sources containing the UTLs PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Pages of 11 Effects Laboratory RFI Site at SSFL July 15, 2015 (ie, for dioxins, an Excel tabte provided by MWH entitled ?Summary Statistics for TEQ and PAH TEQ, Table 5 from the Chemical Soil Background Study entitled Chemical Soil Background Study Chemical Analytes Summary of Statistical Evaluation Results;? and the table entitled "Background Threshold Values Using Combined Chemical Background Data,? from DTSC, 2012. There were seven chemicals for which the selection of the 95-95 UTL was unclear. Please provide an explanation as to how the 95?95 UTL for the following chemicals was determined: Chemical Acenaphth BB-Phthal DE-Phthal Mercury Naphthalene Tin 95-95UTL 0.027 0.0018 0.043 0.0995 0.028 0.001 3.83 (malice): *Abbreviations: 2,4?dichlorophenoxybutyric acid; Acenaphth acenaphthene; BB-Phthal butylbenzyl phthalate; DE-Phthal diethyl phthalate. (13) In the two columns (one for the 0-2 ft dataset, the other for the 0-10 ft dataset) labeled ?Considered it would aid clarity and speed review if a ?yesfno? answer was also supplied in addition to the listed result ?See background statistics." ?See background statistics? should also be footnoted to refer the reader to Attachment 1, Table 4. Finally, footnote-a is incomplete. This footnote refers the reader to the source of the ?Background Concentrations,? for which there are two sources: . Table 5 of the Chemical Study Background Report; and a ?Background Threshold Values [table] Using Combined Chemical Background Data,? in ?Combined-Data Background Threshold Values and Methodology Narrative, Chemical Background Study," DTSC, December 21, 2012. Footnote-a should also identify the Background Concentrations as being UTL-95105 values. Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels): Footnote-a in this table incorrectly refers to the Final Chemical Background Study Report as the source of the UTL-95105 values listed for each radioisotope. It should refer to Radiological Background Study Report (USEPA, 2011). The following comments pertain to Appendix of the 5f9$outh DSFR {Human Health risk Assessment for Hypothetical Future Domestic Use of Chatsvvorth Formati on Groundwater in Boeing RFI Subarea 51'9 South, Ventura County, California): This appendix provides an evaluation of the health risks associated with bene?cial use of area groundwater that generally underlies Subarea SIS-South. The Conceptual Site Model envisions groundwater exposures to the Suburban Resident occurring through ingestion, dermal absorption and inhalation of vapors during showering. Ten groundwater wells are monitored in this region. As calculated in PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 10 of 11 Effects Laboratory RFI Site at SSFL July 15, 2D16 Tables 0-4 to (3-14 in Appendix C, the well point containing groundwater that presents the maximum risk and hazard is HAR-18 (associated with the Systems Test Laboratory IV (STL-IV) RFI Site). Chemical and radiological groundwater data from is used to characterize health risks for each of the RFI Sites located in Subarea 5i9mScuth. HERO comments on Appendix are included below. (19) Attachment 0-1 (Site-Speci?c Suburban Residential Risk-Based Concentrations for Tap Water): HERO sought to reproduce the Tap Water Screening Levels (SLs) listed in this table for the four risldhazard driving chemicals associated with the bene?cial use of Site groundwater (ie, from HAR-18) at the EEL Site. As stated in Section 8.1.1.4 of the EEL HHRA (Groundwater Use Pathway), these compounds were: cis-1,2-dichloroethylene, N-nitrosodimethylamine, trichloroethylene and vinyl chloride. We used the RSL Calculator, accessed via lX?s RSL table website, and inputs speci?ed in Attachment 0-1 of the Subarea SIS?South DSFR to calculate groundwater SLs IX, June 2015). HERO verified the carcinogenic and non-carcinogenic SLs listed in Table E1-10 of Appendix E1 in the EEL HHRA for cis-1,2-dichloroethylene, trichloroethylene and vinyl chloride. The SLs for N-nitrosodimethylamine appear to be in error because this compound was incorrectly identi?ed in Attachment 0-1 as a "non-V00." Thus, the inhalation SL corresponding with VOC inhalation during showering was not calculated. Differences between SLs for N-nitrosodimethylamine listed in Attachment 0-1 with those calculated by HERO are shown below: Compound Source Carcinogenic SLs Non-Carcinogenic SLs (usiL) {Hail-l Inhalation Total Inhalation Total SL SL 8an N-nitrosodimethylamine Attachment 0-1 1.51 E-3 - 1.60E-1 HERO 5.4352 risk-based screening levels for tapwater exposure. ?Total for carcinogenic effects (Total and for non-carcinogenic effects (Total 8an) include the ingestion, dermal absorption and vapor inhalation exposure pathways. HERO reviewed all inputs to columns in Attachment C-1 labeled ?Mutagen?? and and found that all mutagens were correctly identi?ed, but that the following additional ?ve compounds were misidenti?ed as ?non-VOCs?: 1 ,4-Dioxane lsopropanol 1 razine Methyl hydrazine Formaldehyde inhalation 81.5 were not provided for any of these compounds. Please make appropriate corrections to SLs in Attachment 0-1 of DSFR for Subarea SIS-South and to R305, cancer risks and hazard quotients calculated in Table of the EEL HHRA. The above changes in identi?cation of VOCs, as well as potential PM: Julie Lincoln Human Health Risk Assessment for the Environmental HERO Comments on HHRA Page 11 of 11 Effects Laboratory RFI Site at SSFL July 15, 2015 updates in toxicity values, may necessitate recalculation of more groundwater screening levels that identi?ed here, as well as updates to affected soil Finally, the de?nition of a ?volatile compound," as stated in 2 Addendum, should be updated to coincide with new de?nition of a volatile compound. Conclusions and Recommendations: HERO recommends that corrections outlined in Speci?c Comments #1-19 be made and the revised EEL HHRA and SIS?South GW HHRA be re-submitted to DTSC. Reviewed by: I. "x i Jim Polislni, xii Supervising SeniorToxicologist "as; -. a Human and Ecological Risk Of?ce. I, 2' REFERENCES DTSC and URS Corp, ?Chemical Soil Background Study Report.? June 8, 2012a. Available at: Susana Field document DTSC, ?Cover Sheet to: Combined-Data Background Threshold Values and Methodology Narrative, Chemical Soil Background Study." December 21, 2012b. DTSC, HHRA Note Number: 3, DTSC-modi?ed Screening Levels June, 2016. Available at: MWH, "Final Standardized Risk Assessment Methodology Revision 2 Addendum, Santa Susana Field Laboratory, Ventura County, August 2014. IX, ?Regional Screening Levels (Formerly Last updated June 2015. Available at: IX, "Final Radiological Background Study Report, Santa Susana Field Laboratory, Ventura County, California.? October, 2011. Department of Toxic Substances Control Barbara A. Lee Matthew Rodriquez Director Edmund G. Brown Jr. Secretary for Governor Environmental Protection 921 1 Dakdalg Agenue Chatsworth, California 91311 TO: Julie Lincoln, PE Brownfields and Environmental Restoration Program DTSC-Sacramento FROM: Donald v. Greenlee, DABT Mfr/M Staff Toxicologist DATE: April 6, 2016; revised August 10, 2016 SUBJECT: HERO Comments on the ?Human Health Risk Assessment for the Systems Test Laboratory IV RFI Site? (Appendix E1), contained in the Facility Investigation Data Summary and Findings Report, Systems Test Laboratory IV RFI Site, Boeing RFI Subarea 519 South, Santa Susana Field Laboratory, Ventura County, California" PCA: 22120 Site Code-WP: 300232-48 The Human and Ecological Risk Of?ce (HERO) of the Department of Toxic Substances Control (DTSC) reviewed the Human Health Risk Assessment (Section 5 and Appendix E1) component of the Facility Investigation Data Summary and Findings Report, Systems Test Laboratory iV RFI Site, Boeing Subarea 5/9 South, Santa Susana Field Laboratory, Ventura County, California? (herein referred to as dated June, 2015. Section 5 presents a summary of the HHRA and Ecological Risk Assessment (ERA) ?ndings, where the main body of the HHRA and tabulated risk calculations are presented in electronic form as Appendix E1 of the RCRA Facility Investigation Data Summary and Findings Report (DSFR). HERO comments resulting from review of the ERA will be presented under separate cover. As part of the review of the HHRA for the Environmental Effects Laboratory RCRA Facility Investigation Site (EEL Site), HERO reviewed ?Appendix C, Human Health Risk Assessment for the Hypothetical Future Domestic Use of Chatsworth Formation Groundwater in Boeing RFI Subarea 5i9 South? of the Facility Investigation Data Summary and Findings Report, Boeing RFI Subarea 519 South, Santa Susana Field Laboratory, Ventura County, California,? (herein referred to as the Sig-South GW HHRA). HERO's comments on: the STL-IV Site HHRA regarding risk characterization of groundwater as described in Appendix are essentially the same as those for the EEL RFI Site, and are included here to ensure that this review is (E Printed on Recycled Paper PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 2 of 12 Laboratory-IV RFI Site at SSFL August 11, 2016 comprehensive. The STL-IV HHRA was prepared by CHZM Hill for the Boeing Company. comments on review of this HHRA are provided below. Background Boeing Co. recently submitted for the following four RCRA RFI Sites, where all RFI Sites except the Environmental Effects Laboratory (EEL Site) are entirely located in Subarea SIS-South of Administrative Area Ill. The EEL Site is located along the boundary line dividing Administrative Area Ill (Boeing?s responsibility for cleanup) from Administrative Area IV (Department of Energy?s responsibility for cleanup): Systems Test Laboratory IV (STL-IV) Compound A Facility Area Sewage Treatment Plant (STP-B) Environmental Effects Laboratory (EEL) These RFI Sites were historically associated with industrial activities, and multiple chemical use areas have been identi?ed within each RFI Site. Also included were for two separate areas that were unaffiliated with these RFI Sites. The unaf?liated areas are located east and south of the southern-most RFI Site, the STL-IV Site. The southern-most unaf?liated area is located directly south and contiguous with Administrative Areas II, and IV. No industrial activities were performed in the unaffiliated areas, nor did they contain buildings. The purpose of the is to present data and information evaluated to identify sources, nature and extent, transport and fate of chemical and radiological contamination, and to assess potential risks to human health and the environment. This risk information will be used to identify cleanup areas during the Corrective Measures Study. The following comments address discrepancies found during HERO's review of the Human Health Risk Assessment (HHRA) for the STL-IV RFI Site. The HHRA quantitated health risks to a theoretical Suburban Resident and, at Boeing?s option, to a Recreator, resulting from potential exposure to chemicals and radionuclides currently existing at this RFI Site. Exposure pathways included in the cumulative Site health risks were those associated with chemicali?radionuclides identified in Site soils, dust and vapors, and in Subarea SIS-South groundwater (as determined from the groundwater well presenting the greatest health risk within this subarea), is, health risks in the HHRA and in the 519-South GW HHRA: Chemicalsfradionuclides Exposure Chemicalslradionuclides Exposure Pathways Soil, Dust, Vapors Pathways - Groundwater Soil ingestion Ingestion of impacted groundwater Dermal absorption (chemicals) or Dermal absorption (chemicals) or external external exposure (radionuclides) exposure (radionuclides) during Ambient dustlvapor inhalation showering with impacted groundwater Indoor air vapor intrusion from soil Inhalation of vapors during showering gas with impacted groundwater PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 3 of 12 Laboratory-IV RFI Site at SSFL August 11 2016 In accordance with the Standardized Risk Assessment Methodology-Revision 2, Addendum Addendum), health risks associated with consumption of fruits and vegetables grown in an on-Site backyard garden were quanti?ed but were not summed with the above health risks (MWH, 2014). General Comments from Review of the HHRA HERO observed one conceptual error in the Cmpd?A HHRA that must be avoided in future HHRAs--see Comment #1 for details. HERO comments made here for the 5.19 South GW HHRA are applicable to each in the 519 South Subarea because a representative well point (HAR-18), presenting the greatest health risk out of 10 groundwater wells in this Subarea, was used to characterize groundwater health risks at each Subarea South RFI Site. HERO requests responses to the following specific comments: Specific Comments on DSFR Section 5 - Risk Assessment Summary of the STL-IV HHRA: (1) Page 5-2, Section 5.1.3.1 (Estimated Risks HazardsiHypothetical Suburban Residential ScenarioiDirect Contact with Soil): A summary of the risk assessment results is presented in this paragraph, but no reference is made to Table 5-1 which summarizes these add this reference. The first paragraph begins: ?For the direct soil contact pathway, the total site ELCR is 1E-4 and there is no incremental risk above background" [because the Background Risk, which is 2E-4, is also driven by arsenic "However, the inclusion of arsenic as a COPC appears to be biasing the incremental risks downward.? HERO agrees with this conclusion, and recommends that Boeing propose an alternate method to best evaluate and communicate risk when one or more background analytes exist in high enough concentrations to mask Site risks associated with other COPCs. Also include in Table 5.1 the incremental risk for domestic use of impacted groundwater, as summarized on Table (Chemical Risk Summary by Exposure Scenario). This table should be comprehensive in summarizing all potential health risks associated with the hypothetical residential and Recreator use of the Site. (2) Page 5-2, Section 5.1.3.1 (Estimated Risks 8. Suburban Residential ScenarioiDirect Contact with Soil): This paragraph summarizes the incremental cancer risks for the Suburban Resident due to potential exposure to Site-related radionuclides as 1.5E-6. In accordance with the 2 Addendum, please add these radiological risks and risk drivers, as applicable, to the chemical risks shown in Table 5-1. PM: Julie Lincoln Human Health Risk Assessment forthe Systems Test HERO Comments on HHRA Page 4 of 12 Laboratory-IV Site at SSFL August 11, 2015 (3) (4) (5) Page 5-2, Section 5.1.3.2 (Future Recreator ScenarioiDirect Contact with Soil): Based on Boeing?s re-evaluation of an alternative method to evaluate and communicate incremental risk when background risk drivers obscure Site- related risks (Comment please re-evaluate the Site incremental ELCR and HI for the Recreator exposure to soil. Page 5-2, Section 5.1.3.2 (Future Recreator ScenariofDirect Contact with Soil): The second paragraph summarizes potential radionuclide risk results to the Recreator. Please add the results from Table E1-4 (Radiological Risk Summary by Exposure Scenario) to the summarized chemical risks to the Recreator and include all on Table 5-1, or create separate risk summary tables for the Suburban Resident and for the Recreator. 2 Addendum speci?es that chemical and radiological risk results are additive. Page 5-3, Section 5.1.4 (Summary of Findings): The third bullet point should show a cancer risk associated with exposure to Radioisotopes of Concern (ROCs) in soil of 1.5E-6 per Section 5.1.3.1. The cancer risk associated with potential domestic use of shallow groundwater (2E-5) per Table E1-4 (Radiological Risk Summary by Exposure Scenario) should also be listed here. To be consistent with Table E1-3 (Chemical Risk Summary by Exposure Scenario) and Table E?l-4, the second sentence should state that ?For this HHRA, COCs are identified for soil, soil vapor and groundwater." Primary contributors to incremental ELCR and HI estimates should include those listed in Table E1-3 and E1-4 under the ?Primary Contributors to Cancer Risk? and ?Primary Contributors to Hazard index? heading. Boeing?s proposed method of resolving incremental risks when background contributions are elevated (per Comment should be incorporated. Specific Comments on STL-IV HHRA, Appendix E1: (6) Page 2, Section 4.1 (Data Used for the Evaluation and Selection Criteria): This section outlines steps followed to generate the ?nal risk assessment data set. Point number 2 in this section states: ?Soil and soil vapor samples collected from depths greater than 10 ft were removed from the data set, per the SRAM Rev. 2 Addendum." HERO reviewed the SRAM Rev. 2 Addendum and did not find that it provided for limiting the soil vapor VOC data set to soil vapor measurements made from 0-10 ft bgs. Please provide the correct reference for this statement. In addition. Point number 4 states: ?The shallowest soil vapor data from between 5 to 10 ft were used for each sample point." This statement requires a methodology reference, which appears to be Appendix of the Comprehensive Data Quality Objectives, RCRA Facility Investigation, SSFL, Ventura County, CA, March 2013. Please add this reference as a footnote. Also, please address how soil vapor modeling will be addressed it overlying PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 5 of 12 August 11, 2 (7) (3) (9) (10) Laboratory-IV RFI Site at SSFL D16 soils have been excavated to less than a 5 ft soil cover to remove other contaminants. Page 6, Section 8.1.1.1 (Human Health Risk CharacterizationfDirect Contact with Soil): The third complete paragraph from the top of page 6 lists an Exposure Point Concentration for Site lead of 18.5 (0-2 ft bgs) and 15.5 mgikg (0?10 ft bgs). Please reference these values to TableE1-1 (Summary Statistics and Exposure Point Concentrations for Chemicals of Potential Concern). Also, please provide a reference as to the source of the background lead EPC of 15.9 Page 6, Section 8.1.1.1 (Human Health Risk CharacterizationiExposure to Radionuclides in Soil): The second paragraph of this section should state that the incremental Estimated Lifetime Cancer Risks (ELCR) to the Suburban Resident and the Site Recreator (SE-7), as shown on Table E144 (Radiological Risk Summary by Exposure Scenario), associated with potential exposure to radioisotopes identi?ed in on-Site soils, were low. Nevertheless, these cancer risks were added to the incremental chemical risks for the Site, consistent with requirements of SRAivl-Revision 2 Addendum. These incremental radiological cancer risks should also be shown on a cancerlhazard summary table that applies to the entire Site, such as a revised Table E1-3 (Chemical Risk Summary by Exposure Scenario), so that the reader can clearly see that they have been added. Page 7, Section 3.1.1.4 (Groundwater Use Pathway): The last paragraph on this page states that only well point RD-55A, out of 10 groundwater wells in Subarea SIS-South, contained lead (Exposure Point Concentration 40.1 ugi'L) that exceeded the federal Maximum Contaminant Level (MCL) of 15 ugfL. [It would be informative to mention that this is also the California HERO understands that well point HAR-18 was selected to be representative of Subarea SIS-South groundwater because chemical EPCs presented the greatest health risk in this well. However, considering the low detected lead level in HAR-18 (2.9 uglL), the lack of an as yet unde?ned ?No Adverse Effect Level? for lead toxicity on childhood IQ, and, that if groundwater was actually used for bene?cial purposes, it would likely be drawn from the nearest available groundwater location, one of which could be well point RID-55A, please either explain why groundwater at well point should not be considered the equivalent of a lead "hot-spot,? or mention how the groundwater lead concentration at this well point will be dealt with in the CMS phase. Page 8, Section 8.1.2.1 (Direct Contact [of Recreator] with Soil): Referring to Table E1-7 (Chemical-speci?c Incremental Risk and Hazard Estimates for Soil), the second paragraph states: ?For the direct soil contact pathway, the total site ELCR is 4E-5 and there is no incremental risk over background.? The Incremental cancer risk and HQ values should be summed on this table and PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 5 of 12 Laboratory-W RFI Site at SSFL August 11, 2015 (11) (1 2) (13) shown to two decimal points. In addition, the proposed resolution of obscuring incremental Site risks by high background arsenic (per Comment should be applied to Table E1-7. The third paragraph states that the EPC for lead in the 0-2 ft soil layer is 18.5 and the background EPC is 15.9 mgikg. These statements should refer the reader to Table and table of 95% UCLs for background analytes, respectively. Page 8, Section 3.1.2.1 (Direct Contact [of Recreator] with SoiltExposure to ROPCs in Soil): 2 Addendum requires summation of chemical and radiological cancer risks. To be consistent with this, it seems that at least the Incremental [Radiological] Risk for Soil Contact and the Multi-Media [Radiological] Risk for both the Suburban Resident and Recreator should be shown on Table E1-3. Tables E1-4, and E1-8 through E1-10 could be retained to present the details of the radiological risk. Page 9, Section 8.3 (Weight of Evidence Evaluation): HERO agrees with the conclusion that the two (MMH) detections in surface soils appear to be anomalous, and therefore MMH should not be identified as a 000 at the STL-IV RFI Site. Table E1-2 (Summary Statistics and Exposure Point Concentrations (EPCs) for Radionuclides of Potential Concern): This table lists radioisotopes of potential concern detected at the STL-IV Site, descriptive statistics for those radioisotopes that were detected (such as minimum, maximum, mean and standard deviation), and summarizes whether each was selectedlnot selected as an ROPC and if not selected as an ROPC, the reason for exclusion. The details of the ROPC selection process are presented in Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels) where the maximum background concentration for each isotope is compared against either 95(95 UTLs or Background Threshold Values (BTVs), for those isotopes with an insuf?cient number of detections in the Radiologicai Background Study Report IX, 2011) to evaluate statistically. Although radioisotope data is provided in Table 3 for soil between 0-2 ft bgs, there is no data presented under the "0-10 ft bgs? column headings. Examination of the ?lterable radionuclide dataset reveals that there were no samples collected below 2 ft bgs. This was not discussed in the HHRA text under Section 4.0 (Data Used for the HHRA) or Section 5.0 (Chemicals and Radionuclides of Potential Concern), and it is unclear why no deeper samples were collected and tested for radionuclides. Please add an explanation, preferably in Section 4. PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page of 12 Laboratory-Ivr RFI Site at SSFL August 11, 2016 Footnote-c in Table E1-2 refers to the Chemical Background Study and therefore is inappropriate for this table. Please remove it and add a reference to the Radiological Background Study. Footnote-b appears to be incorrect information. It states that ?when more than one recommended UCL was given, the highest was selected as the The text in Section 6.1 states that UCLs were selected based on recommendations of the program, or the maximum result, whichever was lowest. HERO recommends retaining only the second sentence in this footnote, is, ?If the recommended UCL exceeded the maximum, the maximum detect was selected as the (14) Table E1-3 (Chemical Risk Summary by Exposure Scenario): This table summarizes cancer risks and HI values for the Suburban Residential and Recreator exposure scenarios that are derived on Table E1-5 (Risk and Hazard Estimates for Exposure to Soil (0-2 ft bgs), Table E1-S (Risk and Hazard Estimate for Exposure to Background Soil), Table E1-7 (Chemical-Speci?c Incremental Risk and Hazard Estimates for Soil), Table (Risk and Hazard Estimates for Exposure to Soil Vapor), and Table E1-12 (Risk and Hazard Estimates for Exposure to Chatsworth Groundwater). In Table E1-3, the row that summarizes health risks for the Suburban Residential receptor (?Multimedia Risk") includes an incremental cancer risk for direct soil contact of and a total incremental HI of 0.3. Please make corrections to Table E1-3 based on resolution of masking of Site incremental risks by high background arsenic (discussed in Comment Except for the summed risk numbers shown under ?Multimedia Risk,? HERO would prefer that cancer risks and Hl?s in this table be expressed accurate to two significant ?gures so that one can check whether the summed, rounded values under ?Multimedia Risk" are correct. To be compliant with the 2 Addendum, the incremental soil radiological cancer risk Table E1-10) and groundwater radiological cancer risk (1.54E-5) results (Table E1-13 (Radiological Risk Summary by Exposure Scenario)) should be added to the chemical cancer risks provided in Table E1-3 to obtain the ?nal multimedia cancer risk at the Site. (15) Table E1-6 (Risk and Hazard Estimates for Exposure to Background Soil): The heading for column 2 entitled ?Exposure Point Concentration (mg/kg)" should be footnoted to indicate that these values represent 95% UCL values from the. Chemical Background Study datasets, and that these values can be found partially on Table 5 of statistical evaluation of the chemical background data (DTSC URS, 2012), and the remainder on DTSC's combined chemical background data (DTSC, 2012). According to the June 2016 version of HERO Note 3, the non-carcinogenic Soil Screening Level (SSL) for cadmium exposure to the Suburban Resident is 5.2 PM: Julie Lincotn Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 8 of 12 Laboratory-IV RFI Site at SSFL August 11, 2016 mg/kg (DTSC, 2016). The soil RBSL cited in Table lists a value of 4.6 based on an earlier version of HERO Note 3?please ensure this value is updated during the ?nal risk assessment. (16) Table E1-7 (Chemical-Speci?c Incremental Risk and Hazard Estimates for Soil): For the Suburban Residential and Recreator receptor scenarios, this table summarizes for each chemical: (1) total cancer risks and hazard quotients; (2) background cancer risks and hazard quotients; and (3) incremental cancer risks and hazard quotients. On this table, please provide the summed cancer risks and hazard indices for the Total Site, Background and Incremental health risks for both the Suburban Resident and Recreator chemical exposure scenarios. Check to ensure that these values are the same as those on Table (Chemical Risk Summary by Exposure Scenario). This would facilitate review of these ?nal health risk numbers. Preferably the scienti?c notation totals would be expressed to two significant ?gures. (17) Table E1-8 (Risk Estimates for Exposure to Soil Radionuclides (0 to 2 feet bgs): This table summarizes Exposure Point Concentrations (EPCs) for ROPCs detected from 0-2 ft bgs, carcinogenic radioisotope (RAD) Risk-Based Screening Levels previously calculated for the Suburban Residential, Suburban Residential Garden. and Recreational Exposure Scenarios, and the carcinogenic human health risks calculated using these for each exposure scenario. The footnote to Table E1-8 stating that the radiological were derived per an email from Mike BoweriBoeing to Roger Paulson, dated January 14, 2015 is minimally informative and lacks transparency. Please consider re-stating this? as follows: ?Soil Radiological for a Resident were calculated using Preliminary Remediation Goals (PRG) for Radionuclides Calculator (available at: search), where default input values were used except for the following Site-specific inputs: Variable Value (time- .. . . . EDrsa (exposure duration - resident adult) yr _5 iFer-scii (sseesiissisd seii ingestion . .. 1269_??9__ lFAr?adj (age-adjusted soil inhalation factor - resident) m3 _(fruit consumption rate-resident adult) . i 3:733 Jeri-s (iruii seieanm?ienrate -. resident child) arses IR?irfr-e (vegetable eeneumetien rate aidey_ . (vegeteale_seiie.i_i_ntet.ieii - resident chiid) side)! 131%- lFVr-eej . IFFr-edj ingestiseieetai: resideetLe__ PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 9 of 12 Laboratcry-I?llr RFI Site at SSFL August 11,2016 (contaminated plant fraction) unitless 3 1 This same comment also applies to Table E1-9 (Risk Estimates for Exposure to Background Soil Radionuclides) and Attachment 1, Table 7 (Risk Estimates for Exposure to Soil Radionuclides (0-10 ft bgs). Please incorporate the above changes into both Tables E1-B and E1-9. (18) Table E1-10 (Radionuclide-specific Incremental Risk Estimates for Soil): To be consistent with Comment #16 (Table E1-T), please show the summed cancer risks and hazard indices for the Total Site, Background and Incremental health risks for both the Suburban Resident and Recreator exposure scenarios at the bottom of Table E1-10. (19) Table E1-11 (Risk and Hazard Estimates for Exposure to Soil Vapor): This table summarizes Exposure Point Concentrations (EPCs) and calculates cancer risks and hazard quotients for potential indoor inhalation exposures to VOCs detected in soil vapor at the Site. Carcinogenic and non- carcinogenic soil vapor were used to calculate these health risks in accordance with the Sum of Fractions approach (MWH, 2014). HERO noted that several toxicity factors have been updated since the soil vapor were determined in November 2012 (CHZM Hill, 2012), eg, see the latest edition of HERO Note 3 (DTSC, June 2016). Thus during the CMS phase, in accordance with Boeing?s agreement with DTSC, the carcinogenic and non-carcinogenic vapor inhalation will need to be recalculated along with the associated cancer risks and non-cancer hazard quotients for the vapor intrusion pathway. (20) Table E1-12 (Risk and Hazard Estimates for Exposure to Chatsworth Groundwater (Domestic use at Well HAR-18): See Comment #27 (Attachment C1) below which refers to corrections needed for Table E1-12. (21) Table E1-13 (Risk Estimates for Exposure to Radionuclides in Chatsworth (22) Groundwater (Domestic use at Well HAR-13): Footnote-A references the source of the groundwater radionuclide as an email communication between Boeing and DTSC, dated January 14, 2015. This reference should enable the reader to directly lockup the groundwater radionuclide in order to verify their accuracy in this table. Please modify this footnote to achieve this goal?see Comment #17. Finally, the column labeled ?Risk Ratio? should be simpli?ed to ?Cancer Risk." Figure E1 -1 (Conceptual Exposure Model for Potential Human Receptors); This ?gure shows footnote-C referring to groundwater exposures but the footnote- designation is not included in the groundwater exposure routes illustrated In the gure--p ease include it. PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on l-ll-IRA Page 10 of 12 Laboratory-IV RFI Site at SSFL August 11,2016 The following comments pertain to Attachments to Appendix (Human Health and Ecological Risk Assessment Findings for STL-IV RFI Site). (23) Attachment 1, Table 2 (Comparison of Maximum Chemical Concentrations in Site Soil with Background Levels): In the two columns (one for the 0-2 ft dataset, the other for the 0-10 ft dataset) labeled ?Considered it would aid clarity and speed review if a ?yesfno? answer was also supplied in addition to the listed result ?See background statistics." ?See background statistics" should also be footnoted to refer the reader to Attachment 1, Table 4 (Results of Background Statistical Comparisons for Soil). Also, footnote-a is incomplete. This footnote refers the reader to the source of the ?Background Concentrations,? for which there are two sources: . Table 5 of the Chemical Soil Background Study Report; and . ?Background Threshold Values [table] Using Combined Chemical Background Data,? in ?Combined-Data Background Threshold Values and Methodology Narrative, Chemical Background Study,? DTSC, December 21, 2012. Footnote?a should also denote that the_?Background Concentrations? used to determine whether Site chemicals are COPCs are values. (24) Attachment 1, Table 3 (Comparison of Maximum Radionuclide Concentrations in Site Soil with Background Levels): The statistical evaluation for Yttrium?90 is missing from Table 3?please add it. (25) Attachment 1, Table 5 (Aroclor to PCB Congener Extrapolation): Please correct the de?nition of in the table key to ?extrapolation factor" instead of ?extraction factor.? (26) Attachment 1, Table 6 (Risk and Hazard Estimates for Exposure to Soil (0- 10 ft bgs): Please make corrections to the soil for cadmium for all three exposure scenarios (resident, garden and Recreator) as discussed in Comment #15 for Table E1-6. The following comments pertain to Appendix of the 519 South DSFR (Human Health Risk Assessment for Hypothetical Future Domestic Use of Chatsworth Formation Groundwater in Boeing RFI Subarea 5l9 South, Ventura County, California): This appendix provides an evaluation of the health risks associated with beneficial use of area groundwater that generally underlies Subarea 5(9-South. The Conceptual Site Model envisions groundwater exposures to the Suburban Resident occurring through ingestion, dermal absorption and inhalation of vapors during showering. Ten groundwater wells are monitored in this region. As calculated in Tables 0-4 to 0-14 in Appendix C, the well point containing groundwater that presents the maximum risk and hazard is (associated with the Systems Test PM: Julie Lincoln Page 11 of 12 August 11, 2016 Laboratory-I'llr Site at SSFL Laboratory IV (STL-IV) RFI Site). Human Health Risk Assessment for the Systems Test HERDI Comments on HHRA 5l9-South. HERO comments on Appendix are included below. Chemical and radiological groundwater data from HAR-18 is used to characterize health risks for each of the RFI Sites located in Subarea (27) Attachment C-1 (Site-Specific Suburban Residential Risk-Based Concentrations for Tap Water): HERO sought to reproduce the Tap Water Screening Levels (SLs) listed in this table for the four rislo?hazard driving chemicals associated with the bene?cial use of Site groundwater (ie, from HAR-18) at the Site. As stated in Section 8.1.1.4 of the STL-IV HHRA (Groundwater Use Pathway), these compounds were: cis-1,2-dichloroethylene, N-nitrosodimethylamine, trichloroethylene and vinyl chloride. We used the RSL Calculator, accessed via lX?s RSL table website, and inputs speci?ed in Attachment (3-1 of the Subarea 519 South DSFR to calculate groundwater SLs IX, June 2015). Except for slight differences in the non-carcinogenic SL for cis-1,2-DCE (11.4 ugl'L HERO vs 10.4 ugl'L CHZM) and in the carcinogenic SL for vinyl chloride (1.79E-2 ug/L HERO vs ugIL CHZM), HERO veri?ed the carcinogenic and non-carcinogenic SLs listed in Table E1-12 of Appendix E1 in the STL-IV HHRA for cis-1,2-dichloroethylene, trichloroethylene and vinyl chloride. The SLs for N-nitrosodimethylamine appear to be in error because this compound was incorrectly identi?ed in Attachment (3-1 as a ?non- Thus, the inhalation SL corresponding with VOC inhalation during showering was not calculated. Differences between SLs for N-nitrosodimethylamine listed in Attachment 0-1 with those calculated by HERO are shown below: Compound Source Carcinogenic SLs Non-Carcinogenic SLs (uglL) (uglLl Inhalation Total Inhalation Total SL SL 3an N-nitrosodimethylamine Attachment C-1 -- 1.51 E-S -- 1.60E-1 HERO 1.45E-4 5.48E-2 risk-based screening levels for tapwater exposure. ?Total for carcinogenic effects (Total SLC) and for non-carcinogenic effects (Total San} include the ingestion, dermal absorption and vapor inhalation exposure pathways. HERO reviewed all inputs to columns in Attachment C-1 labeled ?Mutagen?? and and found that all mutagens were correctly identi?ed, but that the following additional ?ve compounds were misidentified as ?non?VOCs?: 1 ,4-Dioxane lsopropanol Formaldehyde Methyl hydrazine Inhalation SLs were not provided for any of these compounds. Please make appropriate corrections to SLs in Attachment 0-1 of DSFR for Subarea 5i9 South and to R803. cancer risks and hazard quotients calculated in Table E1-12 of the PM: Julie Lincoln Human Health Risk Assessment for the Systems Test HERO Comments on HHRA Page 12 of 12 Laboratory-IV RFI Site at SSFL August 11, 2015 STL-IV HHRA. The above changes in identi?cation of VOCs, as well as potential updates in toxicity values, may necessitate recalculation of more groundwater screening levels than identified here, as well as updates to affected soil Finally, the de?nition of a "volatile compound," as stated in SRAM- rev 2 Addendum, should be updated to coincide with EPA's new de?nition of a volatile compound. Conclusions and Recommendations: HERO recommends that corrections outlined in Specific Comments #1-27 be made and the revised STL-IV HHRA and 5f9 South GW HHRA be re-submitted to DTSC. Reviewed by: We, l5 I?ll - James Polisini. HLR .. IR ,3er Supervising Toxicologist sew Human and Ecological Risk Of?ce ?a REFERENCES DTSC and URS Corp, ?Chemical Soil Background Study Report.? June 8, 2012. Available at: Susana Field document li bramcfm DTSC, ?Cover Sheet to: Combined-Data Background Threshold Values and Methodology Narrative, Chemical Soil Background Study.? December 21, 2012. DTSC, HHRA Note Number: 3, DTSC-modified Screening Levels June 2016. Available at: MWH, ?Final Standardized Risk Assessment Methodology Revision 2 Addendum, Santa Susana Field Laboratory, Ventura County, August 2014. IX, ?Final Radiological Background Study Report, Santa Susana Field Laboratory, Ventura County, California." October, 2011. Matthew Rodriquez. Secretary for Environmental Protection TO: FROM: DATE: SUBJECT: Department of Toxic Substances Control Barbara A. Lee, Director 8800 Cal Center Drive Sacramento, California 95826?3200 MEMORANDUM Julie Lincoln Senior Hazardous Sustances Engineer Brownfields and Environmental Restoration Program Department of Toxic Substances Control 8800 Cal Center Drive Sacramento, CA 95826 Brian Faulkner, We Senior Toxicologist Ecological Risk Assessment Section (ERAS) Human and Ecological Risk Office (HERO) Department of Toxic SubstanCes Control 8800 Cal Center Drive Sacramento, CA 95826 7/12/2016 ECOLOGICAL RISK ASSESSMENT REVIEW OF RCRA FACILITY Edmund Brown, Governor INVESTIGATION DATA SUMMARY AND FINDINGS REPORT, BOEING RFI SUBAREA 5/9 SOUTH, SYSTEMS TEST LABORATORY IV, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA PCA: 22120 Site Code: 300232-48 Background The Boeing Company recently submitted the draft Data Summary and Findings Reports for Subarea Area 5/9 South of the Santa Susana Field Laboratory (SSFL). Subarea 5/9 South includes four RCRA Facility Investigation (RFI) Sites; the Systems Test Laboratory Compound A, the area portion of the Environmental Effects Laboratory (EEL) and Sewage Treatment Plant for Area Ill Also included was a report that addresses investigations conducted in unaffiliated areas which were not used in historical site activities. The present data from the investigations of these sites, summarize the identified sources of contamination and characterization data, and present conceptual sites models and ecological and human health risk assessments. Additionally, preliminary corrective measures study (CMS) areas are proposed. 4&3 Printed on Recycled Paper Julie Lincoln 7/12/2016 2 The Systems Test Laboratory IV is primarily located within administration area of Subarea 5/9 South, although small portions of the site are located with Administrative Areas II and IV. The Area was used for small rocket and missile engine testing from the mid-1950?s though the early 2000?s. The site includes a total of four test stands, two impoundments and associated channels, fuel and explosive storage areas, leach fields, and buildings. Fuels and oxidizers, including monomethyl hydrazine, nitrogen tetroxide, and inhibited red-fuming nitric acid were used, and trichloroethylene and Freon were used to clean engines between tests. Impoundments were used to collect engine cooling water and wash water. Thirty one chemical use areas (CUAs) have been identified at the STL-IV site. In the report some CUAs have been organized into based on geography and similarities in operational history; a total of thirteen CUA clusters have been identified for the site. The ecological risk assessment methodology for the Boeing sites of Santa Susana Field Laboratory is have been developed in previous documents, and are presented in the Standardized Risk Assessment Methodology (SRAM) revision 2 addendum (MWH, 2014). Only small home range receptors are evaluated in these reports; evaluation of large home-range ecological receptors will be submitted in a separate report after the Sub Area are completed. I Document Reviewed ERAS reviewed the document entitled Facility Investigation Data Summary and Findings Report, Systems Test Laboratory IV RFI Site, Volume 1, Boeing RFI Subarea 5/9 South, Santa Susana Field Laboratory, Ventura County, California.? The report was prepared by and is dated June 2015. These comments were prepared following the review of the STL-IV report. ERAS has subsequently read the reports for Compound A, EEL, and areas, and notes that the comments in this memorandum are generally applicable to all four of the RFI sites included in the DSFR for Subarea Area 5/9 South. Scope of the Review The document was reviewed for scientific content related to the ecological risk assessment. Grammatical or typographical errors that do not affect the interpretation of the text have not been noted. We assume that regional personnel have evaluated the adequacy of site characterization, sampling of environmental media, and analytical chemistry data and quality. General Comments 1. The process for selection of constituents of potential ecological concern (CPECs) and preliminary constituents of ecological concern (COECs) needs to be revised. Julie Lincoln 7/12/2016 3 a. From the SRAM revision 2 (MWH, 2014): ?An HQ or HI based on Low with a value greater than or equal to 1 suggests that additional evaluation is required. An HI calculated using High with a value greater than or equal to 1 indicates exposure exceeds levels associated with adverse effects." And range of ecological risk estimates will allow for more informed risk management decisions to be made for each RFI site, as described in Section 12.4. Chemicals for which the HQ 1 or chemical class HI 1 based on the high will be retained for further ecological evaluation, or analysis of remedial alternatives in the feasibility study The additional evaluation of the chemical concentrations which fall between high and low is not simply to drop them from consideration if they do not demonstrate risk at the level of the high and no hot spots are identified. These may still be COECs, and therefore require additional evaluation before they can be discounted (or not) based on a weight of evidence evaluation. ERAS concurs that if the HQ based on the high is >1 then that chemical should be retained as a COEC. For CPECs in which the HQ based on the low is greater than or equal to 1 and the HQ for the high is less than 1, additional information should be provided fer the chemical to inform risk?management decisions regarding the need for additional evaluation. Examples of relevant considerations may include: Extent of the contamination at theevaluated site Magnitude of the relative to the high and low Number of representative receptors for which HQs exceed 1. Source of and confidence in the selected toxicity reference value (TRV), and the nature/severity of the selected TRV endpoint. . Discussion regarding condition and type of habitat and probability of contaminated site use by the receptor. . Incremental risk/contribution of background to total calculated risk, as applicable 0 Presence/absence of legally protected species within the site area. . How LOAEL-based concentrations/doses compare for COECs which have High based on mid~range effects levels (such as the Region IX BTAG toxicity reference values. There may be other relevant factors to consider as well, depending on site-specific and chemical?specific factors. Incremental risk should not be used as bright line criteria in the selection of preliminary the selection of preliminary COECs should be based on the total Incremental risk should be addressed in the weight of evidence evaluation that is conducted on the preliminary COECs and used for risk management decision?making. By subtracting the background risk first and applying a bright line approach for preliminary Julie Lincoln 4 COEC selection to incremental risks this part of the decision is being taking out of the risk management process, which is where it belongs. Also, it should be noted that the amount of weight given to incremental risk may actually vary by chemical; naturally occurring background constituents such as metals may or may not be considered in the same way as those which are of anthropogenic origin. These decisions should be part of the risk management decision?making process, not applied in the ERA for preliminary COEC selection. 2. Development of cleanup goals and CMS Areas in the Data Summary Reports - Neither the high nor low were developed to be cleanup goals; they were developed to screen for and identify possible risk driving chemicals, and to prioritize chemicals and areas based on levels of risk to ecological receptors. Therefore, developing Corrective Measures Study (CMS) areas based on the is not appropriate. ERAS recommends that cleanup goals be developed for selected COECs and CMS areas be proposed in a future document, following the development of these goals. ERAS defers to project management regarding the best time and place for the presentation of these goals. . ERAS accepts not identifying areas based solely on plant or invertebrate HQs, as per the SRAM revision 2 (MWH. 2014), as there are large uncertainties associated with toxicity values for these receptors. However the calculated risks for chemicals with HQs ?1 for plants and invertebrates should be identified, considered in the weight of evidence evaluation, and discussed in each risk assessment summary of the Data Summary Reports, as noted in General Comment 1a. . Regarding the use of extrapolated data for estimating PCB/Aroclor concentrations, ERAS notes that extrapolated PCB results exceeded the high for mammals and birds at multiple sites. These are presented as CPECs, and then conclusions regarding risks based on these extrapolations are dismissed due to high uncertainty, after which the actual detected concentrations of PCBs are used for a determination of de minimis risk. If these extrapolated data are not useful for decision?making, and these estimated exceedances are to be summarily dismissed in favor of using results based on detected data, then perhaps it is time to reconsider presenting this extrapolated data in the reports. Presenting these results, only to dismiss them in favor of another result, creates risk communication issues. This issue should be discussed and DTSC concurrence sought for a decision to either utilize these values in the risk assessment process or not, and if they are not to be utilized to stop presenting them. Also, given that these results were presented in these draft reports, a clear explanation should be added to the revised reports explaining the. decision that is made to use or remove these values. Julie Lincoln 7/12/2016 5 Specific Comments - Summary 1. Page ES-2: ?Although it is possible that a few (if any) additional areas will be recommended for CMS on the basis of the Large-Home-Range ERA, the findings of this report can confidently be carried into the CMS for future corrective action planning.? This is a speculative statement about a future report, and as such should be removed. 2. Section 5.2.3.1 (Soil Exposure Pathway), page 5-5, fifth bullet. The appendix named in the bullet (E1) is the HHRA, not the ERA, which is appendix E2. Also, Appendix E2 only has six sections. Please correct and check the document for errors. 3. Table 4?1, page 3 of 23 (STL-IV CUA Cluster 2) ?Study Question Do concentrations of chemicals within CUA Cluster exceed Action Levels??, and ?The results of the ecological risk assessment indicate that the hazard quotient for ecological receptors exceeds 1. However, concentrations in STL-IV CC 2 do not pose unacceptable risks to ecological receptors." a. Please define an ?Action Level? in the context of this table. b. The way the latter statement is written it appears that a risk management decision is being made without input from agency risk managers, as risk~ based levels were exceeded and a recommendation of no further action has been decided without agency concurrence. This is a global comment, as this same language occurs in multiple places in the table. Appendix E2, (Ecological Risk Assessment for the Systems Test Laboratory IV Site). 4. Section 2.2.1 (Ecological Setting). This section should. cite previous biological survey reports that were conducted at SSFL, such as the 1997 Biological Conditions report (Ogden, 1997). Please add. ERAS also recommends noting that a great deal of biological survey work has been conducted on?site by the- other responsible parties and other stakeholders, such as the bird banding activities of the San Fernando valley Audubon Society, for example. Cumulatively these efforts have contributed to a better understanding of the biology of the site. 5. Section 2.1.3.1. (Data Evaluation and Selection Criteria). Please revise the sentence which states, ?The depth to groundwater exceeded typical to reference the specific depth that is used to determine consideration of groundwater in ecological risk assessment (6 ft. bgs.) and cite the SRAM Rev 2 Addendum (MWH, 2014). Julie Lincoln 7/12/2016 6 6. Section 2.1.3.1. (Data Evaluation and Selection Criteria). ?Soil and soil vapor samples collected from depths greater than 6 feet were excluded because they are beyond the typical exposure range for ecological receptors.? This is acceptable for the ecological risk evaluation, as burrowing animal exposures are generally considered in the 0?6 ft soil horizon. However, this is dependent on the existence of sufficient data in the 0?6 ft soil horizon to assess current exposures. lf shallow data is lacking or not sufficient, this could represent a potential data gap and deeper data might be useful to evaluate potential exposures. if this is the case for any soil vapor evaluations ERAS may not agree with excluding soil vapor samples from depths greater than 6 feet bgs. ERAS recommends that the text be revised to clarify the approach for soil vapor evaluation. 7. Section 2.2.1.2 (Exposure Point Concentrations). biphenyl (PCB) congeners were not evaluated for at the For clarity and to avoid confusion for lay people who read this please reword this sentence to make it clear that PCBs were evaluated at the site, just not evaluated on a congener- specific basis. Conclusions The ecological risk assessment section of the report is well organized and presented, and the calculations of ecological risks are consistent with the SRAM Rev 2 Addendum (MWH. 2014). The selection of preliminary COECs needs to be revised as noted above, and agency risk management input should be required for the selection of final COECs and development of cleanup goals and CMS areas. References Ogden, 1997 Biological Conditions Report, Santa Susana Field Laboratory, Ventura County, California. June. r-u. . . it?. t? Reviewed by: James Eichelberger, . gel?? ?get? 2 Staff Toxicologist Cc: James M. Polisini, Supervising Toxicologist Department of Toxic Substances Control Barbara A. Lee, Director 700 Heinz Avenue Berkeley, California 94710-2721 Matthew Rodriquez Secretary for Environmental Protection Edmund G. Brown Jr. Governor MEMORANDUM TO: Roger Paulson, Unit Chief Supervising Hazardous Substances Engineer I Santa Susana Lab Project, Cal Center Sacramento Office Brownfields and Environmental Restoration Program FROM: Buck King, P.G. 6353, C.HG. 433 Senior Engineering Geologist, Geological Services Unit Geologic Services Branch Brownfields and Environmental Restoration Program Thomas Seckington, P.G. 6460, C.HG. 739 Senior Engineering Geologist, Geological Services Unit Geologic Services Branch Brownfields and Environmental Restoration Program DATE: SUBJECT: August 23, 2016 DRAFT RCRA FACILITY INVESTIGATION DATA SUMMARY AND FINDINGS REPORT, BOEING RFI SUBAREA 5/9 SOUTH, DATED JUNE 2015. Project: DTSC300232-00 Activity: 22120 DOCUMENTS REVIEWED Draft RCRA Facility Investigation (RFI) Data Summary and Findings Report, Boeing RFI Subarea 5/9 South. 9 Volumes. Dated June 2015 INTRODUCTION This memorandum provides comments regarding the Boeing RFI Subarea 5/9 South, Data Summary and Findings Report (DSFR). The DSFR is a 9 volume document consisting of 6 reports titled Subarea 5/9 South, Environmental Effects Laboratory (EEL) RFI Site, Area III Sewage Treatment Plant (STP) RFI Site, Compound A Facility RFI Site, System Test Laboratory (STL) IV RFI Site, and Areas Unaffiliated With RFI Sites. Comments are referenced to either individual reports or if applicable multiple reports comprising the Printed on Recycled Paper Roger Paulson August 23, 2016 Page 2 of 13 Subarea 5/9 South DSFR If you have any questions or need additional information, please contact Buck King at (510) 540-3955 or buck.king@dtsc.ca.gov or contact Thomas Seckington at (714) 484-5424 or tom.seckington@dtsc.ca.gov. The following general comments apply to each report comprising the DSFR. 1) The purpose of the approach presented in Appendix C, Potential Transport of Contaminants in Vadose Zone to Groundwater, is to assess areas for further consideration in the Corrective Measures Study (CMS). The approach presented in the Data Summary and Findings Reports (DSFR) uses soil and groundwater data along with a soil vadose zone transport computer model to assess if contamination reached or will reach groundwater. The approach relies heavily on computer modeling as a surrogate for bedrock vadose zone data, which is very limited over the entire SSFL site. Although the DSFR often implies that the overall approach overestimates the current and future risk to groundwater, there is uncertainty associated with the approach and representativeness with many of the assumptions. As a result, this approach cannot be considered conservative, but rather, viewed as a screening tool for eliminating from further consideration, in a CMS, those areas with limited vadose zone contamination AND with adequate data to indicate groundwater has not been impacted and will not be impacted by a potential source in the vadose zone. 2) The DSFR is part of the RFI process at the site. As such, it is a step in charactering the nature and extent of contamination, in the vadose zone and in groundwater, with the objective of collecting adequate information for evaluating remedial alternatives and assessing risk. In the RFI process, aquifer restoration is the initial assumption as the remediation goal for groundwater. Therefore, the use of GCVs (groundwater comparison values) or MCLs (maximum contaminant levels) in this approach should be used with the understanding that any potential present or future impact to groundwater must be considered in CMS. It should also be further acknowledged that GCVs and MCLs are derived differently (i.e. background versus regulatory values established for municipal drinking water, respectively) and, therefore, comparisons of concentration values to regulatoryestablished concentrations should be used prudently. 3) For chemicals that exceeded their respective Background Threshold Values (BTV) or GCVs in vadose zone samples but were not detected or detected at or below their respective GCVs in groundwater samples, the estimated maximum leachate concentration (EMLC) is calculated based on SESOIL modeling of the maximum concentration reported in the vadose zone using average conditions for RI cluster. It is not clear how the vertical concentration profile is generated for each cluster. Attachment C-2 describes the process but some clarification is needed: Roger Paulson August 23, 2016 Page 3 of 13 a. What is the rationale for using the BTV established for inorganics in soil for the values used in the WS/UWS? b. It is assumed that the maximum reported concentration is identified by cluster. However, for a cluster that contains data from multiple borings at multiple depths, is the calculation of the concentration gradient calculated from the data of the single boring with the single maximum reported concentration or is it calculated from the highest reported concentrations at each depth regardless of the boring? c. If the maximum concentration is reported in a boring with a depth corresponding to the WS/UWS then the concentration is applied to the alluvium/colluvium and only to a depth of the sample. This approach appears to minimize the potential for transport. What is the rationale for the assumption that the concentration attenuates immediately to a zero concentration below the deepest sample? 4) The DSFR states that chemicals with exceedances in both the vadose zone and groundwater AND chemicals with predicted EMLCs greater than their respective GCVs were further evaluated in the transport modeling evaluation. This “further evaluation” was not proposed or presented in the March 2013 Approach for Evaluating Vadose Zone Mass Flux of Contaminants to Groundwater, Revision 2 or the May 2014 Potential Transport of Contaminants in Vadose Zone to Groundwater: Environmental Effects Laboratory. The GSU does not believe that the “further evaluation” is necessary to complete the RFI and recommends that chemicals with exceedances in both the vadose zone and groundwater OR chemicals with any predicted leachate concentrations through soil transport modeling should be further evaluated in the CMS. This “further evaluation”, however, may be presented in the CMS. It should be noted, though, that use of the process described in the “further evaluation” presents many of the identical concerns and questions presented in this memorandum regarding the use of SESOIL. At a minimum, these questions and concerns will need to be resolved prior to any approval for its use. 5) The use of the most recent data to model vadose zone transport over a 100-year period would represent transport over the next 100 years. It does not represent transport from 50 years ago to 50 years in the future, as stated in the DSFR. Although not acknowledged in the DSFR, contaminate concentrations in the soil and soil vapor decrease over time due to numerous processes (for example: volatization, dilution, degradation, etc.) and, as a result, concentrations reported within the past few years WOULD NOT represent the highest concentrations historically present in the vadose zone or, historically, the greatest risk to groundwater. As a result, evaluations of the past transport from the vadose zone to groundwater should be almost entirely based on the impacts reflected in the groundwater data and any reported impact to groundwater should be further Roger Paulson August 23, 2016 Page 4 of 13 evaluated in the CMS. 6) Please provide the calculations for converting soil vapor data to the soil matrix concentrations used in the vadose modeling and the assumptions used for the conversation. The GSU could not locate them in the DSFR. 7) The GSU recommends clarification on how the estimated contaminant transport distances in groundwater were determined (Appendix C). Appendix C states: “To estimate the extent of chemical transport from likely or confirmed sources at an RFI Site, the length of forward particles paths (i.e., paths starting at sources and advancing through the flow field) were truncated based on the mean Darcy flux under both pumping and non-pumping conditions. The Darcy flux along the particle paths generated for an RFI Site is equal to the total particle track length divided by the time it takes to flow along the flow path based on a porosity of 1.” It is not clear if the “total particle track length” is 1,000 meters, which is previously referenced, or some other length. Further, the significance of statement “the time it takes to flow along the flow path based on a porosity of 1” is not clear. The 2009 RI Report stated: “Particle tracking is used to illustrate SSFL groundwater flow directions and relative groundwater velocity using the Darcy flux. The dual porosity nature of the fractured rock at SSFL does not allow for specification of a single porosity value to represent groundwater flow velocities in the EPM [equivalent porous media] model. The particle tracking presented in this report uses a default porosity of 1.0, which allows comparison of the Darcy flux (i.e., relative velocity) along flow paths in different areas of the model. The particle tracks illustrated in this report are intended solely for the depiction of flow directions in a given model simulation. As such, the length of depicted particle tracks does not reflect contaminant transport distance or travel time.” These statements, in the 2009 RI Report and Appendix C, need some reconciliation and/or clarification. Darcy flux is represented as where the velocity of flow ( is the discharge ( ) divided by the cross-sectional area of flow ( ) or hydraulic conductivity (K) times the hydraulic gradient ( .  The particle tracks in the model, however, were calculated using the equation for seepage velocity or average linear velocity (which accounts for a porous media). Roger Paulson August 23, 2016 Page 5 of 13 The equation is: ) of 1.0 is used for the particle tracking to A default porosity or effective porosity remove the effect of the porous media and to set seepage velocity equal to Darcy Flux. The 2009 RI Report states that this approach was used in the past because it was not possible to determine a representative single porosity. Without a representative porosity, contaminant transport distances or times cannot be determined. Representative porosities for sandstones at the site would range from 5% to 30% resulting in seepage velocities 3 to 20 times greater than those calculated using Darcy Flux (i.e. porosity of 1). Further, in the Technical Memorandum- Conceptual Site Model, Movement of TCE in Chatsworth Formation (2000) seepage velocity or average linear velocity was calculated using bulk hydraulic conductivity, groundwater gradient, and fracture porosity and stated “that the average linear groundwater velocity at SSFL ranged from 500 to 10,000 feet per year.” GSU recommends further clarification on the use of Darcy Flux for estimating contaminant transport distances and how this would represent a conservative approach. 8) The following comments address the SESOIL Transport Modeling Inputs and Assumptions: a. “In the event that there were an insufficient number of measurements to calculate the median groundwater elevation for a cluster, groundwater data from a longer timeframe, from 2010 through 2013, were used. If a significant change in groundwater elevation occurred in a well between 2010 and 2013, that well was excluded from the calculation of the median groundwater elevation.” Additional clarification is needed. What is meant by “insufficient number of measurements to calculate the median” and “significant change in groundwater elevation”? b. “The median soil (Alluvium/Colluvium [A/C]) portion of the profile was subtracted from the calculated total thickness of the vadose zone profile; the remaining profile was established as the thickness of the weathered sandstone/unweathered sandstone (WS/UWS) portion.” Was WS/UWS encountered in all clusters and, if not, has was the thickness Roger Paulson August 23, 2016 Page 6 of 13 represented? Was there variability in the depth encountered and, if so, how was that represented? Clarification is needed on how the soil thickness measurements, ground surface elevations, and depth to water measurements are averaged to calculate the thickness of the WS/UWS. Is there consideration of the previous ground surface elevations or subsurface structures (i.e., basements, sumps, underground storage tanks) in setting up the transport model? c. “Vertical concentration profiles (sublayer loads) were developed based on the maximum concentrations detected and available sampling results from the vadose zone sampled locations for each chemical. Per the Recommended Approach for Evaluating Vadose Zone Mass Flux of Contaminants to Groundwater (MWH, 2013; Appendix D of the DQO Report [CH2M HILL, 2013]), the organic chemicals modeled in this exercise were assumed not to occur naturally in the subsurface environment [emphasis added], particularly in the WS/UWS portion of the profile.” The GSU was not clear about the significance of this statement. Please provide additional clarification on how this assumption would affect the evaluation of the area? d. “For the WS/UWS portion of the profile, 0 mg/kg or respective BTVs were assigned [emphasis added] for organic and inorganic chemicals, respectively, unless the second sample was collected from the WS/UWS portion of the profile. In this latter case, organic chemical concentrations were assigned an initial (i.e., time “0”) value of 0 mg/kg [emphasis added], while the inorganic chemical concentrations were assigned as their respective BTVs for the remaining portion of the WS/UWS profile.” Clarification is needed on the difference between “assigning 0 mg/kg” and “assigning an initial (i.e., time “0”) value of 0 mg/kg.” e. “A range of groundwater recharge values for each CC were obtained from the calibrated groundwater flow model as presented in the Site-wide Groundwater Remedial Investigation Report (MWH, 2009). The Pierce College file in the SESOIL climate database was selected for RFI sites and their associated CCs and presented in the SESOIL model output report on the “Climate Report” page.” The groundwater flow model was not developed to provide recharge rates for the individual RFI areas. The recharge values taken from the model can be used as a starting point but professional judgment must be used to determine if the value is reasonable given the conditions at the individual RFI area. f. “The soil disconnected index (SDI), effective porosity (EP), and intrinsic permeability (IP) values were varied as necessary in the application file to Roger Paulson August 23, 2016 Page 7 of 13 achieve the range of estimated recharge from the flow model for each CC.” The IP values used for WS/UWS may be more representative of unfractured sandstone and may be too low. Further discussion should be presented on the selection of IP and the process for varying SDI and EP. g. “In the event that there were an insufficient number of measurements to calculate the median groundwater elevation for a cluster, groundwater data from a longer timeframe, from 2010 through 2013, were used. If a significant change in groundwater elevation occurred in a well between 2010 and 2013, that well was excluded from the calculation of the median groundwater elevation.” Additional clarification is needed. What is meant by “insufficient number of measurements to calculate the median” and “significant change in groundwater elevation”? Please address the effects of the regional drought on the water level measurements at the site over the past decade. Are the water levels reported since 2010 representative of non-drought / normal precipitation conditions? 9) It is not clear what groundwater comparison values (GCVs) are. The DSFR states “These data were screened against groundwater characterization values (GCLs) to evaluate the presence of chemicals at concentrations above their GCLs at the site and to identify data gaps. Groundwater comparison values (GCVs) used in the Potential Transport of Contaminants in Vadose Zone to Groundwater (Appendix C of this report), are numerically equivalent to GCLs.” What is the difference between the GCVs and GCLs? The GSU recommends that the DSFR clarify what these terms represent and, more importantly, how they differ. 10) Figure D-2. The figure state as one of the decision questions “Is the % NDs > 50% and the % detects < 25% for a given chemical at one well location?” Please provide clarification on this question. Does the “and” require that % NDs be greater than (>) 75% so that detections are less than (<) 25%. The GSU recommends clarification. 11) Due to the protracted drought conditions in California, the GSU recommends that the relationship between contaminant concentrations and water levels be evaluated for each well to ensure that recent data, to be used in CMS, is representative of the current concentration present in the groundwater and not artifact of unusually low water levels. Roger Paulson August 23, 2016 Page 8 of 13 SPECIFIC COMMENTS Report Location 1 2 Subarea 5/9 South DFSR Appendix B -3D Visualization of Groundwater Subarea 5/9 South DFSR Appendix B -3D Visualization of Groundwater Table, Figure, or Location Comment Figure 9 Missing date/year labels on three water level elevation plots and 3 pumping history bar charts shown on figure. Pumping rate label (gallons per minute?) missing from 3 of the pumping history bar charts. Figure 12 Missing date/year labels on chemical concentration versus time plots. Missing concentration units label on concentration versus time graphs. In the DSFR, chemicals identified in the vadose zone to have potential future impacts on groundwater are recommended for groundwater monitoring instead of evaluation in the Corrective Measures Study (CMS). 3 4 5 EEL RFI Site DSFR EEL RFI Site DSFR Appendix C Potential Transport of Contaminants in Vadose Zone to Groundwater, EEL RFI Site DSFR Appendix C Potential Transport of Contaminants in Vadose Zone to Groundwater, Section 6-2 The identified vadose zone chemicals and associated areas must be recommended for further evaluation in the CMS. In addition, the identified vadose chemicals must be comprehensively monitored within the RFI site as part of the groundwater monitoring program beginning 1st quarter 2017 and on a semi-annual basis. A proposal for the additional monitoring and sampling should be submitted within 45 days for DTSC approval. It should include, at a minimum, the specific groundwater monitoring wells and the associated chemicals to be sampled and analyzed for. Page C-10, Table The “Total Number of Chemicals with Exceedances in the Vadose Zone” for Compound A CC1 should be 53 not 54. Page C-12, Table For Compound A CC3, the previous table had 52 chemicals and this table only accounts for 51. Likewise, for Compound A CC4, the previous table had 70 chemicals and this table only accounts for 68. Roger Paulson August 23, 2016 Page 9 of 13 Report Location 6 EEL RFI Site DSFR Appendix C Potential Transport of Contaminants in Vadose Zone to Groundwater, Table, Figure, or Location Page C-13 7 EEL RFI Site DSFR Appendix C Potential Transport of Contaminants in Vadose Zone to Groundwater, Page C-13, Table 8 EEL RFI Site DSFR Appendix D – Groundwater Source Zone and Plume Characterization, Table D-1 9 EEL RFI Site DSFR Appendix D – Groundwater Source Zone and Plume Characterization, Figure C-3 Comment The text “The transport modeling conducted for the vadose to groundwater evaluation produced highly conservative results for chemicals that readily degrade because the transport model does not account for biodegradation. Thus it is recommended that the vadose zone CMS areas and locations presented above be revisited during CMS to consider natural attenuation processes” should be removed. GSU believes that the vadose zone to groundwater evaluation is at best a screening level evaluation and that due to simplifying assumptions inherent in the SESOIL modeling, the vadose zone evaluation results are not “highly conservative”. The recommendation that identified CMS areas be revisited to consider natural attenuation processes is unspecific regarding which chemicals are being referred to and unnecessary in this document. Issues such as natural attenuation processes will likely be considered for appropriate chemical in the CMS regardless of this vague recommendation. The identified text recommended for removal also occurs in Data Summary and Finding Report Page 6-2 and also should be removed. The number do not match the previous table: CC1 had 41 chemicals previous in the previous table with 42 accounted for in this table ; CC3 had 46 chemicals previous in the previous table with 48 accounted for in this table; and CC4 had 58 chemicals previous in the previous table with 59 accounted for in this table Table D-1 indicates that dissolved boron and dissolved strontium exceeded Groundwater Cleanup Levels in historical data but were not subsequently analyzed for during acquisition of recent data collected between 2010 and 2014. These two analytes should be identified as a data gap and included in future groundwater monitoring at EEL to characterize their current status and potential for CMS evaluation. The particle track indicates a lack of coverage towards the west of the EEL, north of RS-37 and RS-17. An additional groundwater monitoring well(s) appears to be needed to delineate contaminant transport in this direction. Without further information, the GSU recommends the installation of one or more wells located and constructed based on the 3D particle tracks. Roger Paulson August 23, 2016 Page 10 of 13 Report Location Table, Figure, or Location Comment In the DSFR, chemicals identified in the vadose zone to have potential future impacts on groundwater are recommended for groundwater monitoring instead of evaluation in the Corrective Measures Study (CMS). 10 Area III STP RFI Site DSFR 11 Area III STP RFI Site DSFR Appendix C - Potential Transport of Contaminants in Vadose Zone to Groundwater 12 Area III STP RFI Site DSFR Appendix C – Potential Transport of Contaminants in Vadose Zone to Groundwater, Section 6-2 Page C-8 Page C-13 The identified vadose zone chemicals and associated areas must be recommended for further evaluation in the CMS. In addition, the identified vadose chemicals must be comprehensively monitored within the RFI site as part of the groundwater monitoring program beginning 1st quarter 2017 and on a semi-annual basis. A proposal for the additional monitoring and sampling should be submitted within 45 days for DTSC approval. It should include, at a minimum, the specific groundwater monitoring wells and the associated chemicals to be sampled and analyzed for. Text indicates that WS-11 and RS-41 were the only wells successfully sampled as part of vadose zone to groundwater evaluation. The list of groundwater analyses for the two wells does not include VOCs. It is unclear why VOC were not included in list of analysis. Table C-ES-1 clearly indicates that VOCs have been detected in soil and soil vapor at the site. VOC analysis of groundwater is recommended to support RFI evaluation. The text “The transport modeling conducted for the vadose to groundwater evaluation produced highly conservative results for chemicals that readily degrade because the transport model does not account for biodegradation. Thus it is recommended that the vadose zone CMS areas and locations presented above be revisited during CMS to consider natural attenuation processes” should be removed. GSU believes that the vadose zone to groundwater evaluation is at best a screening level evaluation and that due to simplifying assumptions inherent in the SESOIL modeling, the vadose zone evaluation results are not “highly conservative”. The recommendation that identified CMS areas be revisited to consider natural attenuation processes is unspecific regarding which chemicals are being referred to and unnecessary in this document. Issues such as natural attenuation processes will likely be considered for appropriate chemical in the CMS regardless of this vague recommendation. The identified text recommended for removal also occurs in Data Summary and Finding Report Page 6-2 and also should be removed. Roger Paulson August 23, 2016 Page 11 of 13 Report Location 13 14 15 Area III STP RFI Site DSFR Appendix D – Groundwater Source Zone and Plume Characterization Compound A Facility RFI Site DSFR Compound A Facility RFI Site DSFR Appendix C – Potential Transport of Contaminants in Vadose Zone to Groundwater Table, Figure, or Location Page D-6 Page 6-2 Page C-16 Comment Text indicates that VOCs, NDMA, formaldehyde and fluoride have been detected in groundwater above GCLs. The text indicates that these chemical are believed to result from adjacent RFI sites. The text should be revised to specify the adjacent RFI site believed to be source of these chemicals and provide a stronger argument as to why these chemical detections in groundwater could not be related to Area III STP. The GSU believes that these chemicals could be related to waste waters historically conveyed to the site. In the DSFR, chemicals identified in the vadose zone to have potential future impacts on groundwater are recommended for groundwater monitoring instead of evaluation in the Corrective Measures Study (CMS). The identified vadose zone chemicals and associated areas must be recommended for further evaluation in the CMS. In addition, the identified vadose chemicals must be comprehensively monitored within the RFI site as part of the groundwater monitoring program beginning 1st quarter 2017 and on a semi-annual basis. A proposal for the additional monitoring and sampling should be submitted within 45 days for DTSC approval. It should include, at a minimum, the specific groundwater monitoring wells and the associated chemicals to be sampled and analyzed for. The text “The transport modeling conducted for the vadose to groundwater evaluation produced highly conservative results for chemicals that readily degrade because the transport model does not account for biodegradation. Thus it is recommended that the vadose zone CMS areas and locations presented above be revisited during CMS to consider natural attenuation processes” should be removed. GSU believes that the vadose zone to groundwater evaluation is at best a screening level evaluation and that due to simplifying assumptions inherent in the SESOIL modeling, the vadose zone evaluation results are not “highly conservative”. The recommendation that identified CMS areas be revisited to consider natural attenuation processes is unspecific regarding which chemicals are being referred to and unnecessary in this document. Issues such as natural attenuation processes will likely be considered for appropriate chemical in the CMS regardless of this vague recommendation. The identified text recommended for removal also occurs in Data Summary and Finding Report Page 6-2 and also should be removed. Roger Paulson August 23, 2016 Page 12 of 13 Report Location Table, Figure, or Location Comment In the DSFR, chemicals identified in the vadose zone to have potential future impacts on groundwater are recommended for groundwater monitoring instead of evaluation in the Corrective Measures Study (CMS). 16 STL IV RFI Site DFSR Page 6-3 17 STL IV Facility RFI Site DSFR Appendix C – Potential Transport of Contaminants in Vadose Zone to Groundwater C-16 The identified vadose zone chemicals and associated areas must be recommended for further evaluation in the CMS. In addition, the identified vadose chemicals must be comprehensively monitored within the RFI site as part of the groundwater monitoring program beginning 1st quarter 2017 and on a semi-annual basis. A proposal for the additional monitoring and sampling should be submitted within 45 days for DTSC approval. It should include, at a minimum, the specific groundwater monitoring wells and the associated chemicals to be sampled and analyzed for. The text “The transport modeling conducted for the vadose to groundwater evaluation produced highly conservative results for chemicals that readily degrade because the transport model does not account for biodegradation. Thus it is recommended that the vadose zone CMS areas and locations presented above be revisited during CMS to consider natural attenuation processes” should be removed. GSU believes that the vadose zone to groundwater evaluation is at best a screening level evaluation and that due to simplifying assumptions inherent in the SESOIL modeling, the vadose zone evaluation results are not “highly conservative”. The recommendation that identified CMS areas be revisited to consider natural attenuation processes is unspecific regarding which chemicals are being referred to and unnecessary in this document. Issues such as natural attenuation processes will likely be considered for appropriate chemical in the CMS regardless of this vague recommendation. The identified text recommended for removal also occurs in Data Summary and Finding Report Page 6-3 and also should be removed. Roger Paulson August 23, 2016 Page 13 of 13 Report Location Table, Figure, or Location Comment Table D-2 needs to be revised to clarify the “-“ note which indicates that the chemical was “not reported as detected” or “not a target analyte.” The distinction is important and needs to be clear. 18 Appendix D – Human Health and Ecological Risk Assessment for Surface Water in the Southwest Drainage of Boeing RFI Subarea 5/9 South Table D-2 The “Report on Seeps Investigation, Santa Susana Field Laboratory” (Pierce et al., 2015) indicates that FDP-890 and FDP-890 pool have not been sampled for radionuclides. The GSU recommends that the facility sample the surrounding “SP” wells associated with the seeps (SP-881, SP-890, and SP882). They have only been sampled for tritium and would not have the higher turbidity that may have impacted the Gross Alpha and Gross Beta readings in seep FDP-881. Samples collected from the “SP” wells will be more representative of the water discharging from the seeps prior to interaction with the surface sediments.