FINAL FORMER MCAS TUSTIN RAB SUMMARY (11 October 2018) Page 1 of 10 Document Control Number: MMEC-2405-0007-0034
Meeting Location: Tustin Senior Center, 200 South C Street, Tustin, California Meeting Date/Time: 11 October 2018/7:00 PM to 8:23 PM Summary Prepared by: Gabriela Staehle, Multi-Media Environmental Compliance Group (MMEC Group)
Results of Groundwater Sampling for Per- and Polyfluoroalkyl Substances (PFAS) in Operable Unit 3 and Carve-Outs 5 and 6
Results of Groundwater Sampling for 1,2,3-Trichloropropane (1,2,3-TCP) in Operable Unit 1A
Attendees: A total of 16 people were in attendance for the Former MCAS Tustin RAB meeting:
Navy: Jim Callian, Base Realignment and Closure (BRAC) Environmental Coordinator (BEC) and RAB Co-Chair; Guy Chammas, Navy Lead Remedial Project Manager (LRPM); Rich Pribyl, Contracted Environmental Engineering Support (EES); and Alex Bollweg, Contracted EES.
Regulatory Agencies: Patricia Hannon, California Regional Water Quality Control Board, Santa Ana Region (RWQCB).
RAB Members: Desir Leg, RAB Community Co-Chair; Ken Piguee, City of Tustin (City); Matt West, City; Chris Crompton, Orange County Public Works Department; and Mary Opel, South Orange County Community College District (SOCCCD).
Other Attendees: Erika Rodriguez, Community Member; Harry Takach, Community Member; Medhanie Ephrem, SOCCCD; Tony Guiang and Gabriela Staehle, MMEC Group; and Zoila Finch, County of Orange.
Mr. Callian (BEC and RAB Co-Chair) welcomed everyone to the 107th Former MCAS Tustin RAB meeting and thanked everyone for attending. Mr. Callian asked for self-introductions from those in attendance.
Mr. Callian presented the general slides, including the following: the RAB Meeting Agenda; points-of-contact information for the Former MCAS Tustin BRAC Cleanup Team (BCT), including RWQCB and California Department of Toxic Substances Control (DTSC); information and contact information for the Administrative Record and Information Repository; environmental websites; the schedule for the next RAB meeting; and the process for review of RAB Meeting Summaries.
Mr. Chammas (Navy LRPM) noted that the figure on the poster board at the front of the room had been updated to show the current groundwater plume delineations.
Final FORMER MARINE CORPS AIR STATION (MCAS) TUSTIN
107th Restoration Advisory Board (RAB) Meeting Summary
11 October 2018
FINAL FORMER MCAS TUSTIN RAB SUMMARY (11 October 2018) Page 2 of 10 Document Control Number: MMEC-2405-0007-0034
RAB PRESENTATION 1:
Results of Groundwater Sampling for PFAS in Operable Unit (OU) 3 and Carve-Outs (COs) 5 and
6 (Presented by Mr. Bollweg, Contracted ESS [Attachment 1])
Slide 1 Presentation Title
Slide 2 Presentation Overview
Slide 3 OUs and Groundwater Plumes (Figure)
Mr. Bollweg described the figure on Slide 3: CO-5 and -6 are outlined with yellow dashed lines, the trichloroethene (TCE) and 1,2,3-TCP plumes are shown as pink and yellow polygons, respectively, and the groundwater flow direction is shown with blue arrows. Mr. Bollweg explained that Mr. Pribyl would discuss the TCE and 1,2,3-TCP plumes in depth during his presentation.
Slide 4 OUs and Groundwater Plumes (continued)
Mr. Bollweg briefly discussed the locations, characteristics, and established remedies for the groundwater plumes in OU-1A, OU-1B North/South, OU-3, and OU-4B.
Slide 5 PFAS Background
Mr. Bollweg discussed the nature and historical use of PFAS compounds in industrial and consumer products and indicated that although PFAS are not currently regulated as a hazardous substance, the Navy is voluntarily and proactively conducting groundwater investigations
Slide 6 Potential PFAS Source Areas
Mr. Bollweg introduced the Fire/Rescue Station Area of Concern (AOC) in OU-1A and the Crash Crew AOC in OU-1B North.
Slide 7 Potential PFAS Source Areas (continued)
Mr. Bollweg discussed potential source areas in OU-3 (Crash Crew Burn Pits) and the Warehouse AOC in OU-4B. He also mentioned that although the Navy has not identified any general or specific AOCs in CO-6, PFAS releases may have been associated with wastewater treatment in this area.
Slide 8 OU-3 Investigation Technical Approach
Mr. West (City) asked Mr. Bollweg to clarify the detection limits for perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and PFOA+PFOS. Mr. Bollweg explained that the detection limits depend on the lab and dilution factors. Mr. Chammas added that the detection limits are in the range of single digits in parts per trillion (ppt). The screening level for PFOA, PFOS, and PFOA+PFOS is 70 ppt, and the Navy can detect concentrations at single-digit ppt.
Regarding the sampling conducted in November 2017, Mr. Bollweg explained that only 9 of 10 wells were sampled because one well was dry.
Slide 9 OU-3 Investigation Results (Table)
FINAL FORMER MCAS TUSTIN RAB SUMMARY (11 October 2018) Page 3 of 10 Document Control Number: MMEC-2405-0007-0034
Mr. Bollweg presented the results from the November 2017 investigation at OU-3 and noted that concentrations in the second water-bearing zone (WBZ) were up to 3 orders of magnitude less than those in the first WBZ.
Slide 10 OU-3 Investigation Results (continued), First WBZ (Figure)
Mr. Bollweg explained that the groundwater flow direction is west toward Peters Canyon Channel and that a steel-reinforced concrete containment wall on the western side of Peters Canyon Channel is in place to prevent groundwater migration into the channel.
Slide 11 OU-3 Investigation Results (continued), Second WBZ (Figure)
Mr. Bollweg noted again that PFOA and PFOS concentrations in the second WBZ were significantly less than those in the first WBZ.
Slide 12 COs 5 and 6 Investigation Technical Approach
Mr. Bollweg indicated that similar to the previous investigation at OU-3, the Navy was interested in determining the presence or absence of PFAS in shallow groundwater in COs 5 and 6. The Fire/Rescue Station, Warehouse, and Crash Crew AOCs along with the OU-1A/1B North and OU-1B South Groundwater Treatment Facilities were the focus of the investigation.
Slide 13 COs 5 and 6 Investigation Fire/Rescue Station and Warehouse AOCs Results (Figure)
Mr. Bollweg indicated that PFOA, PFOS, and/or PFOA+PFOS exceedances were detected in each of the permanent and temporary monitoring wells that were sampled.
Slide 14 COs 5 and 6 Investigation Crash Crew AOC Results (Figure)
Mr. Bollweg indicated that PFOA, PFOS, and PFOA+PFOS exceedances were detected in each of the permanent and temporary monitoring wells that were sampled.
Slide 15 COs 5 and 6 Investigation OU-1A/1B North Groundwater Treatment Facility Results (Figure)
Mr. Bollweg indicated that although there were PFOA, PFOS, and PFOA+PFOS exceedances detected in the influent, the liquid-phase granular activated carbon (GAC) treatment train effectively reduced their concentrations to non-detect concentrations in the effluent sample.
Slide 16 COs 5 and 6 Investigation OU-1B South Groundwater Treatment Facility Results
Mr. Bollweg indicated that, similar to the OU-1A/1B North Groundwater Treatment Facility results, although there were PFOA, PFOS, and PFOA+PFOS exceedances detected in the influent, the liquid-phase GAC treatment train effectively reduced their concentrations to non-detect concentrations in the effluent sample.
Mr. Callian pointed out that the numbers preceding the U or nondetect values in the callout boxes are the detection limits. The number means that the constituent was not detected at or above that concentration.
Slide 17 Next Steps
FINAL FORMER MCAS TUSTIN RAB SUMMARY (11 October 2018) Page 4 of 10 Document Control Number: MMEC-2405-0007-0034
Mr. Bollweg indicated that the Navy was currently finalizing its summary report for the COs 5 and 6 investigation and strategizing with the regulatory agencies and stakeholders regarding the next steps. Additional groundwater investigation is being planned, with fieldwork expected to be completed in Spring 2019 and reporting to be completed in Summer 2019.
Slide 18 Acronyms
Slide 19 Questions
Ms. Opel (RAB Member) asked what the difference in depth is between the first and second WBZs. Mr. Bollweg responded that the first WBZ extends to 30 feet below ground surface (bgs) and the second WBZ extends from 30 feet to 60 feet bgs.
Ms. Leg (RAB Community Co-Chair) asked whether the Navy has a conceptual strategy for the second round of sampling. Mr. Bollweg responded that the Navy is still discussing the strategy, but will likely return to CO-5, CO-6, and OU-3. Mr. Callian added that the Navy will use a phased approach and will continue to adjust the plan according to the locations of detections.
Ms. Leg noted that the highest concentrations were detected in OU-3, west of Peters Canyon Channel and she expressed concern with the likelihood of contaminants migrating into the channel. Mr. Chammas responded that a containment wall is installed between OU-3 and the channel, which acts as an effective barrier. It was previously estimated via groundwater modeling that it will take approximately 60 years for groundwater to travel around the containment wall.
Ms. Leg asked about the degradation rates of the PFAS constituents. Mr. Chammas responded that the PFAS constituents undergo minimal degradation. Ms. Leg asked whether the Navy was required to conduct stormwater sampling in Peters Canyon Channel. Mr. Chammas responded