APPENDIX A I. Public Notification of Field Work. DRAFT PEA REPORT AOI-1, AOI-2 AND AOI-3 Beverly Hills High School. EAI Project No.

Transcription

1 DRAFT PEA REPORT AOI-1, AOI-2 AND AOI-3 Beverly Hills High School APPENDIX A I Public Notification of Field Work BHM;2751;ORAFTPEAREPORT-AOll EAI Project No. 2751

2 ***** Beverly Hills U nifled School District CREATING A WORLD CLASS EDUCATION 255 S. Lasky Drive Beverly Hills, CA = Main = Fax TO: Neighbors and Other Interested Parties of the Beverly Hills High School Improvement Project DATE: May 28, 2015 FROM: SUBJECT: Beverly Hills Unified School District Environmental Investigation at Beverly Hills High School The Beverly Hills Unified School District (BHUSD) would like to provide you with advance notice of an environmental investigation that will be conducted at the Beverly Hills High School, 241 S. Moreno Drive, as part of the proposed modernization of the school. The investigation will be performed by a licensed contractor and will consist of the sampling of soil, soil gas and ground water for any hazardous materials. The BHUSD is conducting the work with the oversight of the Department of Toxic Substances Control (DTSC). Although an assessment will be conducted, this does not mean hazardous substances are located on this property. Recently enacted state laws recommend that school sites undergo a complete environmental review, and if necessary, a cleanup to protect students, faculty and staff at the school. Field work is scheduled to be conducted on June 3, 4, 5, 8 and 9, All field work will be conducted during normal business hours. Street closures will not be necessary during the investigation. The BHUSD will submit the results of this Preliminary Endangerment Assessment (PEA) to DTSC for review; DTSC may require the BHUSD to modify or revise the PEA, or may concur with it as written. The PEA will include an assessment of whether hazardous materials are present and, if so, whether the materials are present in concentrations that would require some type of cleanup or mitigation before modernization efforts are implemented. The BHUSD will hold a public hearing to discuss the investigation results, and will take public comment. All comments received in this process shall be forwarded to DTSC for consideration. When the public participation process is complete, DTSC will issue a final determination with regard to the PEA. If you have any questions concerning the upcoming investigation please contact Dr. Gary Woods, Superintendent of the BHUSD at (310) , ext or Ms. Scarlett Xihong Zhai Project Manager, DTSC at (714) BEVERLY HILLS HIGH SCHOOL. HORACE MANN BEVERLY VISTA. HAWTHORNE. EL RODEO

3 DRAFT PEA REPORT AOI-1. AOI-2 AND AOI-3 Beverly Hills High School APPENDIX B I DTSC Comment Letter dated June 9, 2015 and EAI Responses BHM :2751:DRAFTPEAREPDRT-ADll EAI Project No. 2751

4 Matthew Rodriquez Secretary for EnvIronmental Protection Department of Toxic Substances Control. Barbara A. Lee, Director 5796 Corporate Avenue Cypress, California Edmund G. Brown Jr. Govemor June 9, 2015 Dr. Gary Woods, Superintendent Beverly Hills Unified School District 255 South Lasky Drive Beverly Hills, California REVIEW OF PRELIMINARY ENVIRONMENTAL ASSESSMENT WORKPLAN, BEVERLY HILLS HIGH SCHOOL, 214 S. MORENO DRIVE. BEVERLY HILLS. CA (SITE" CODE: ) Dear Mr. Woods: The Department of Toxic Substances Control (DTSC) reviewed the Draft Preliminary Environmental Assessment Workplan (Workpl~n) prepared on behalf of the Beverly Hills Unified School District (District) by Environmental Audit Inc. (EAI), dated May and received on May The Workplan includes background information and proposed investigation activities for the Beverly Hills High School site (Site). According to the Workplan. the approximately 25-acre 'Site is located at 240 S. Moreno Drive, Beverly Hills. in Los Angeles County, California. Beverly Hills High School (BHHS) was originally built in From 1909 to the present. various areas of the BHHS were leased for oil field activities, e.g. oil wells, sumps. and aboveground storage tanks. A 120-gallon underground storage tank was removed from the BHHS in and closure letters were obtained in Some concerns on soil gas and indoor air arose in which lead to numerous investigations from 2003 to Based on the results of these investigations. it was determined that the air quality at the BHHS was not measurably different from that at other locations in the Los Angeles Basin. Land use west of BHHS Was commercial with residential development surrounding the campus in all other directions. Based on its review, DTSC identified discrepancies in the Workplan that require clarification or modification. The enclosed comments identified discrepancies. Please submit a table with responses to the enclosed comments and a revised document by June 14,2014. The table should restate each comment and provide the associated ~esponse and where the comment was incorporated into the revised dpcument. If you have any questions regarding this project, please contact Xi hong Scarlett Zhai. * Printed on Recycled Paper

5 Mr. Gary Woods June 9, 2015 Page 2 Project Manager, at (714) or by atxihong.zhal@dtsc.ca.gov. or contact me at (714) or by atshahir.haddad@dtsc.ca.gov. Shahir Haddad, P.E. Supervising Engineer Schools Evaluation and Brownfield Cleanup Branch Brownfields and Environmental Restoration" Program ka/xsz/ Enclosure cc: (via ) Mr. Steve Bright President Environmental Audit Inc. sbright@envaudit.com Mr. Shahir Haddad Supervising Engineer DTSC Schools Evaluation and Brownfields Cleanup Branch - Cypress Shahir. Haddad@dtsc.ca.gov Mr. Donald Greenlee Staff Toxicologist DTSC Human and Ecological Risk Office - Chatsworth Donald.Greenlee@dtsc.ca.gov Mr. Joe Hwong Senior Geologist DTSC Schools Evaluation and Brownfields Cleanup Branch - Cypress Joe.Hwong@dtsc.ca.gov Schools Evaluation and Brownfields Cleanup Branch Re.ading File

6 DTSC COMMENTS DRAFT PRELIMINARY ENVIRONMENTAL ASSESSMENT WORKPLAN BEVERLY HILLS HIGH SCHOOL BEVERLY HILLS, CALIFORNIA The fol/owing DTSC staff reviewed and provided comments herein to the Workplan. Original comments from the DTSC Engineering/Geology and Human and Ecological Risk Offices are available for review in DTSC project files. All questions regarding these comments should be directed to the Project Manager. Dr. Xihong (Scarlett) Zhai Project Manager Schools Evaluation and Brownfield Cleanup Branch - Cypress Xihong.Zhai@dtsc.ca.gov GENERAL COMMENTS: 1. The DTSC agrees with the proposed PEA investigation strategy. However, some fine adjustment to sample locations and data evaluation processes are provided in the comments below, which should be incorporated in the revised Workplan. SPECIFIC COMMENTS: 1. Page 28. Section AOI-1 Portable Trailers Location 1: The text in this section should state the groundwater sample collection and analysis to oe consistent with Table 1. This comment also applies to Section 5.7.2, AOI-2 Portable Trailers. Location 2. Donald Greenlee Staff Toxicologist DTSC Human and Ecological Risk Office (HERO) - Chatsworth Donald.Greenlee@dtsc.ca.gov SPECIFIC COMMENTS: 1. HERO found this Workplan to be clearly constructed and comprehensive. We had only a few minor comments as noted below. SPECIFIC COMMENTS: 1. Page 25. Section Develop a Decision Rule. Second Sentence: This sentence states: "If concentrations of the COPC are less than the SLs, no further action will be required." HERO notes that this conclusion mayor may not apply, depending on the accumulative cancer risks and hazard quotients for the Site. Soil screening levels are typically calculated assuming that the chemical in question is the only contaminant contributing to health risk. It would be more accurate to state: "If concentrations of all COCs correspond with a cancer risk

7 DTSC Comments Draft Preliminary Environmental Assessment Workplan Beverly Hills High School Page 2. and hazard index that are below Site target levels t required." no further action will be 2. Page 30. Section Soil Gas Investigation/Probe Installation Methods,: The first paragraph states that a 1Ia th inch 00 Nylaflow tubing with a stainless steel filter mesh/screen tip and gas tight fitting at. the surface will be used [for collection of, soil gas samples]. DTSC generally recommends that inert tubing, such as Teflon tubing, be used to avoid adherence to, or reaction with, the tubing by compounds such as naphthalene (DTSC, 2012). 3. Table 3. List of Method Compound and Reporting Limits for Soil Gas: HERO compared the Method TO-15 Reporting Limits (RLs) listed in Table 3 with Residential Air RSLs (EPA, 2015) for seven VOCs (including BTEX - target analytes for this former oil producing area) and methane and hydrogen sulfide. We found that the reporting limits for the following three VOCs exceeded their respective RSLs: benzene (3.2 ug/m 3 RUO.36 ug/m 3 RSLJ; ethylbenzene (4.4 ug/m 3 RU1.1 ug/m 3 RSL); and trichloroethylene (5.5 ug/m RU0.48 ug/m 3 RSL). Method TO-15 detection limits were not provided. HERO recommends that Environmental Audit ensure that Method TO-15 detection limits for all VOCs of interest are below their respective RSL, and request that such 'results be J-flagged, to ensure that soil gas results will yield data that are health protective. 4. Appendix 0, Table 1, Summary of Soil Gas Testing Results Geotechnical Hazard Study - Area 1 [AOI-11: Appendix 0 summarizes 2011 soil and soil gas test results for three 25-ft deep borings installed by EAI along the northern perimeter of AOI-1. Table'1 shows that the maximum benzene in soil gas in each boring at 5 ft bgs ranged from ug/m 3. At the time, these values were close to but less than the CHHSL for soil gas beneath a foundation without engineered fill. Because CHHSLs have not been updated since 2010, HERO prefers to calculate either site-specific soil gas screening levels (SGSLs) or use conservative SGSLs calculated assuming an attenuation factor of 0.05 for an existing slab and indoor air screening levels (SLs) as listed in HERO ~ote 3 (DTSC, 2013). HERO recalculated the SGSLs for both benzene and toluene, the only VOCs listed in Appendix 0, Table 1 of this PEA Workplan using attenuation factors calculated using DTSC's J&E Soil Screen vapor intrusion modeling program and residential air RSLs listed by EPA-Region IX (DTSC, 2014; EPA, 2015; see table below). We found that nohe of the soil gas levels for benzene or toluene measured at either 5 ft, 15 ft or 25 ft below ground surface (bgs) exceeded our SGSLs that were calculated for a 5 ft depth. Because SGSL values would only increase with depth, we agreed that none of the benzene levels (range: ug/m3) or toluene levels (range: ug/m3) measured in soil gas between 5-25 ft bgs at AOI-1 would exceed their respective SGSLs.

8 DTSC Comments Draft Preliminary Environmental Assessment Workplan Beverly Hills High School Page 3 VOC Residential AirScreening Level* Attenuation Cancer Non- Factor (a.)*'" (ug/m 3 ) Cancer (ug/m 3 ).Benzene 8.4E E-3 Toluene E-3 * Per HERO Note 3, Table 3. ** Per HERO Soil Gas (J&E) ~creenlng Model (Dec 2014 update) Depth Soil Gas (ft bgs) Screening Level (ug/m3) E5 5. Appendix D. Table 4. Summary of Soil Testing Results Geotechnical Hazard Study - Area: Table 4 lists results for Title 22 metals, TPH carb<?n fractions, VOCs and SVOCs for the nine soil samples collected from the three borings installed at AOI-1. Where available, these results were also compared in Table 4 with EPA-Region IX soil screening levels (SSLs) and OEHHA California Human' Health Screening Levels (CHHSLs). HERO noted that both sets of screening levels should be updated. HERO recently issued Note 3 which specifies our preference for selected screening levels (DTSC, 2013). To update the screening levels listed in Appendix D, Table 4, refer first to HERO Note 3 for appropriate SSLs, and if not listed there, use the Regional Screening Level (RSL) listed by USEPA-Region IX (USEPA, 2015). For lead, use a 95% UCL of 80 mglkg as a residential SSL per HERO Note 3. Using updated soil screening levels, we agree that none of the test results present a significant concern to public health. Mr. Joe Hwong, PG Senior Geologist DTSC Schools Evaluation and Brownfields Cleanup Branch - Cypress joe. hwong@dtsc.ca.gov SPECIFIC COMMENTS: 1. Page 17. tables: CHHSL was used to compare to concentrations of chemical detected in soil gas, which is inappropriate. The Regional Screening Levels (RSLs) by the USEPA Region 9 should be used for such comparison. 2. Page 3~. Section Probe Installation Methods, and Figure 11: Based on DTSC's experiences, the permanent soil vapor probes are likely to be plugged by moisture after time when 1/8-inch Nylon tubing is used. Therefore, it is recommended a larger-diameter tubing/casing be used for the permanent soil vapor probes.

9 DTSC Comments Draft Preliminary Environmental Assessment Workplan Beverly Hills High School Pag~4 3. Page 36. Section Soil Gas Samples: The Workplan proposes to use hand-held equipment for methane and H2S. In addition, based on the investigation results conducted by EAI in December 2011, methane was detected in all soil gas samples at 1,000 ppmv, which may be the error readings caused by the hand-held equipment. Therefore, the DTSC recommends the hand-held equipment calibrated with low detection limits be used during the sampling event. For QA/QC purpose, the DTSC recommends 20% of these soil gas samples be collected and delivered to a fix laboratory for methane and H2S analyses. 4. Figure 9: The DTSC concur with the proposed sampling locations, depths, and analyses for Areas AOI-1 and AOI-3. As for AOI-2, because two oil weus were formerly located, the DTSC recqmmends SG-4 be moved close to oil well"rodeo 106" and adding one more soil gas location close to oil well II Beverly Hills High School #1". Screen depths for these 2 soil gas probes should be at 5, 15,30 and. 40 feet below ground surface (ft bgs). VOCs, naphthalene, methane, and H2S will be analyzed in soil gas samples from 5, 15, and 30 ft bgs; and only methane and H2S will be analyzed in the 40 ft bgs soil gas samples. In addition, the DTSC recommends SG-1 and SG-2 be moved to close to the historic sumps and spills areas at north. 5. Figure 12: A 25-foot screen was proposed for construction of groundwater monitoring wells at AOI-1 through AOI-3. Unless there is a need for such longscreen due to fluctuation of groundwater elevations beneath the site, a shorter screen (such as 15-foot) is more suitable for groundwater well installation. In addition, a same well number of MW-1 was used for the three different wells in three AOls (as shown on Figures 8 through 10), which need to be revised to avoid confusion.

10 RESPONSES TO DTSC COMMENTS ON PEA WORK PLAN DATED MAY 1, 2015 BEVERLY HILLS HIGH SCHOOL The following provides responses to Department of Toxic Substances Control (DTSC) comments on the Preliminary Endangerment Assessment (PEA) Work Pan prepared by Environmental Audit, Inc. (EAI) for the Beverly Hills High School (BHHS) dated May 1, The comments are contained in a letter prepared by the DTSC dated June 9, 2015, a copy of which is attached hereto. The letter contained comments from Dr. Xihong (Scarlett) Zhai - DTSC Project Manager, Donald Greenlee - DTSC Staff Toxicologist, and Joe Hwong, PG - DTSC Senior Geologist. The comments and responses have been identified to correspond to the specific comment numbers identified in the DTSC Project Manager, Staff Toxicologist and Senior Geologist comments. Dr. Xihong (Scarlett) Zhai Project Manager Schools Evaluation and Brownfield Cleanup Branch - Cypress Xihong.Zhai@dtsc.ca.gov GENERAL COMMENTS: 1. The DTSC agrees with the proposed PEA investigation strategy. However, some fine adjustment to sample locations and data evaluation processes are provided in the comments below, which should be incorporated in the revised Work Plan. Response: Comment noted, no response necessary. SPECIFIC COMMENTS: 1. Page 28, Section 5.7.1, AOI-1 Portable Trailers Location 1: The text in this section should state the groundwater sample collection and analysis to be consistent with Table 1. This comment also applies to Section 5.7.2, AOI-2 Portable Trailers Location 2. Response: Groundwater collection and analysis for all wells installed was conducted in accordance with the analyses listed in Table 1. BHM :2751:RES-DTSC-COMMENT5-JUNE

11 Donald Greenlee Staff Toxicologist DTSC Human and Ecological Risk Office (HERO) - Chatsworth Donald.Greenlee@dtsc.ca.gov SPECIFIC COMMENTS: 1. HERO found this Work Plan to be clearly constructed and comprehensive. We had only a few minor comments as noted below. Response: Comment noted, no response necessary. SPECIFIC COMMENTS: 1. Page 25, Section 4.5.5, Develop a Decision Rule, Second Sentence: This sentence states: "If concentrations of the COPC are less than the SLs, no further action will be required." HERO notes that this conclusion mayor may not apply, depending on the accumulative cancer risks and hazard quotients for the Site. Soil screening levels are typically calculated assuming that the chemical in question is the only contaminant contributing to health risk. It would be more accurate to state: "If concentrations of all COPC correspond with a cancer risk and hazard index that are below Site target levels, no further action will be required." Response: Comment noted and the cumulative effects of all COPC detected were evaluated as part of the risk assessment process. 2. Page 30, Section , Soil Gas Investigation/Probe Installation Methods,: The first paragraph states that a 1/8th inch 00 Nylaflow tubing with a stainless steel filter mesh/screen tip and gas tight fitting at the surface will be used [for collection of soil gas samples]. DTSC generally recommends that inert tubing, such as Teflon tubing, be used to avoid adherence to, or reaction with, the tubing by compounds such as naphthalene (DTSC, 2012). Response: Comment noted. Based on correspondence with the DTSC Project Manager, nylaflow tubing is acceptable and was used for this project. 3. Table 3, list of Method Compound and Reporting limits for Soil Gas: HERO compared the Method TO-15 Reporting limits (RLs) listed in Table 3 with Residential Air RSLs (EPA, 2015) for seven VOCs (including BTEX - target analytes for this former oil producing area) and methane and hydrogen sulfide. We found that the reporting limits for the following three VOCs exceeded their respective RSLs: benzene (3.2 ug/m 3 RL/0.36 ug/m 3 RSL); ethyl benzene (4.4 ug/m 3 RL/1.1 ug/m 3 RSL); and trichloroethylene (5.5 ug/m 3 RL/0.48 ug/m 3 RSL). Method TO-15 detection limits were not provided. HERO recommends that Environmental Audit ensure that Method TO-15 detection limits for BHM:2751:RES-DTSC-COMMENTS-JUNE

12 all VOCs of interest are below their respective RSL, and request that such results be J flagged, to ensure that soil gas results will yield data that are health protective. Response: This comment referenced RLs associated with indoor residential air and should have referenced RLs associated with soil gas. As discussed with the DTSC Staff Toxicologist, the RLs referenced in Table 3 for soil gas are all below their respective screening levels. 4. Appendix D, Table 1, Summary of Soil Gas Testing Results Geotechnical Hazard Study - Area 1 [AOI-l]: Appendix D summarizes 2011 soil and soil gas test results for three 25-ft deep borings installed by EAI along the northern perimeter of AOI-l. Table 1 shows that the maximum benzene in soil gas in each boring at 5 feet bgs ranged from ug/m 3. At the time, these values were close to but less than the CHHSL for soil gas beneath a foundation without engineered fill. Because CHHSLs have not been updated since 2010, HERO prefers to calculate either site-specific soil gas screening levels (SGSLs) or use conservative SGSLs calculated assuming an attenuation factor of 0.05 for an existing slab and indoor air screening levels (SLs) as listed in HERO Note 3 (DTSC, 2013). HERO recalculated the SGSLs for both benzene and toluene, the only VOCs listed in Appendix D, Table 1 of this PEA Work Plan using attenuation factors calculated using DTSC's J&E Soil Screen vapor intrusion modeling program and residential air RSLs listed by EPA Region IX (DTSC, 2014; EPA, 2015; see table below). We found that none of the soil gas levels for benzene or toluene measured at 5 feet, 15 feet or 25 feet below ground surface (bgs) exceeded our SGSLs that were calculated for a 5 foot depth. Because SGSL values would only increase with depth, we agreed that none of the benzene levels (range: ug/m3) or toluene levels (range: ug/m3) measured in soil gas between 5-25bgs at AOI-l would exceed their respective SGSLs. VOC Residential Air Screening Level Attenuation Depth Soil Gas Cancer Non-Cancer Factor (a)" (feet bgs) Screening (ug/m 3 ) (ug/m3) Level (ug/m3) Benzene 8.4E E Toluene E ES Per HERO Note 3, Table 3.. Per HERO Soil Gas (J&E) Screening Model (Dec 2014 update) Response: Comment noted. The referenced table was from a report prepared in 2012 when CHHSLs were being used for screening purposes. All soil gas screening levels used for the PEA were based on HERO Note 3 and DTSC guidance contained in its report titled "Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air {Vapor Intrusion Guidance)," dated October Appendix D, Table 4, Summary of Soil Testing Results Geotechnical Hazard Study - Area: Table 4 lists results for Title 22 metals, TPH carbon fractions. VOCs and SVOCs for the nine soil samples collected from the three borings installed at AOI-l. Where available, BHM:2751:RE5-DTSC-COMMENTS-JUNE

13 these results were also compared in Table 4 with EPA-Region IX soil screening levels (SSLs) and OEHHA California Human Health Screening Levels (CHHSLs). HERO noted that both sets of screening levels should be updated. HERO recently issued Note 3 which specifies our preference for selected screening levels (DTSC, 2013). To update the screening levels listed in Appendix 0, Table 4, refer first to HERO Note 3 for appropriate SSLs, and if not listed there, use the Regional Screening Level (RSL) listed by USEPA Region IX (USEPA, 2015). For lead, use a 95% UCL of BO mg/kg as a residential SSL per HERO Note 3. Using updated soil screening levels, we agree that none of the test results present a significant concern to public health. Response: Comment noted. See response to comment 4 above, all screening levels were updated accordingly. Mr. Joe Hwong, PG Senior Geologist DTSC Schools Evaluation and Brownfields Cleanup Branch - Cypress joe.hwong@dtsc.ca.gov SPECIFIC COMMENTS: 1. Page 17. tables: CHHSL was used to compare to concentrations of chemical detected in soil gas, which is inappropriate. The Regional Screening Levels (RSLs) by the USEPA Region 9 should be used for such comparison. Response: The referenced tables were from a report prepared in 2012 when CHHSLs were being used for screening purposes. All soil gas screening levels used for the PEA were based on HERO Note 3 and DTSC guidance contained in its report titled "Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (Vapor Intrusion Guidance)," dated October Page 30. Section 5.B.2.l Probe Installation Methods. and Figure 11: Based on DTSC's experiences, the permanent soil vapor probes are likely to be plugged by moisture after time when 1/B-inch nylon tubing is used. Therefore, it is recommended a largerdiameter tubing/casing be used for the permanent soil vapor probes. Response: The nylaflow tubing size for all soil vapor probes was increased to 1/4-inch diameter. 3. Page 36. Section Soil Gas Samples: The Work Plan proposes to use hand-held equipment for methane and H2S. In addition, based on the investigation results conducted by EAI in December 2011, methane was detected in all soil gas samples at 1,000 ppmv, which may be the error readings caused by the hand-held equipment. BHM :2751:RES-DTSC-COMMENTS-JUNE

14 Therefore, the OTSC recommends the hand-held equipment calibrated with low detection limits be used during the sampling event. For QA/QC purpose, the OTSC recommends 20% of these soil gas samples be collected and delivered to a fix laboratory for methane and H2S analyses. Response: In addition to hand held instrument readings, soil gas samples were also collected and delivered to the laboratory for methane analysis using U.S. Environmental Protection Agency (EPA) Method 8015 and H2S using EPA Method Figure 9: The OTSC concur with the proposed sampling locations, depths, and analyses for Areas AOI-l and AOI-3. As for AOI-2, because two oil wells were formerly located, the OTSC recommends SG-4 be moved close to oil well "Rodeo 106" and adding one more soil gas location close to oil well "Beverly Hills High School #1". Screen depths for these 2 soil gas probes should be at 5, 15, 30 and 40 feet below ground surface (feet bgs). VOCs, naphthalene, methane, and H2S will be analyzed in soil gas samples from 5, 15, and 30 feet bgs; and only methane and H2S will be analyzed in the 40 feet bgs soil gas samples. In addition, the OTSC recommends SG-l and SG-2 be moved to close to the historic sumps and spills areas at north. Response: Sample location A2-SG4 was moved closer to oil well "Rodeo 106" and sample location A2-SG5 added near oil well "Beverly Hills High School #1". Soil gas samples were not collected at depths deeper than 30 feet bgs. 5. Figure 12: A 25-foot screen was proposed for construction of groundwater monitoring wells at AOI-l through AOI-3. Unless there is a need for such long- screen due to fluctuation of groundwater elevations beneath the site, a shorter screen (such as 15- foot) is more suitable for groundwater well installation. In addition, a same well number of MW-l was used for the three different wells in three AOls (as shown on Figures 8 through 10), which need to be revised to avoid confusion. Response: Well screen intervals were shortened as requested. Well designations were modified to include the AOI before the well 10 number, i.e., the three ground water wells installed as part of this investigation are identified as follows: AOI Ground Water Well 10 1 AI-MW-l 2 A2-MW-l 3 A3-MW-l BHM :2751:RES-DTSC-COMMENTS-JUNE

15 DRAFT PEA REPORT AOI-1, AOI-2 AND AOI-3 Beverly Hills High School APPENDIX C I Assessor's Parcel Map BHM:2751:DRAFTPEAREPORT-AOll EAI Project No_ 2751

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