Meeting Minutes

Agenda Item #1. Introduction

Mr. Karson, a community involvement specialist with the Air Force, convened the meeting at 6:30 PM and introduced Ms. Foster, the Jacobs Engineering Group project manager for the Fuel Spill 28 (FS-28) and FS-29 plumes. He stated that available tonight are copies of the agenda, the FS-28/FS-29 Proposed Plan, the presentation slides, and the Joint Process Action Team’s (JPAT’s) recommendations and concerns regarding the FS-28/FS-29 Proposed Plan.

Mr. Karson reviewed the agenda and noted that written comments on the proposed plan can be submitted to the Air Force until the public comment period ends on March 11, 2000. He noted that comments can be submitted by mail, fax, e-mail, or through the Massachusetts Military Reservation (MMR) web site. Mr. Karson noted that there will be a period for questions and answers after Ms. Foster’s presentation, and then the public hearing will begin. He noted that during the formal public hearing people can provide oral comments or questions; however, responses will not be given tonight.

Agenda Item #2. FS-28/29 Proposed Plan

Ms. Foster noted that the information provided tonight will be a recap and a general overview of the remedial alternatives being considered. She displayed a map and pointed to the Southwest Operable Unit (SWOU) and to the FS-28 and FS-29 plumes.

FS-28

Ms. Foster reported that a lot of investigation of the FS-28 plume has been conducted over the past few years. The Air Force has a good understanding of the nature and the extent of the plume, and many remedial action activities already have taken place. Ms. Foster noted that most of the ethylene dibromide (EDB) mass is located in the southern portion of the plume. She reported that residences in this area have been connected to municipal water and there is no current risk to human health or the environment. She stated that previously EDB was discharging into the Coonamessett River; however, EDB has not been detected in the river since May 1999. This change in conditions is attributed to the success of Extraction Well 1 (EW-1) and the shallow well-point extraction system. Ms. Foster pointed to the Coonamessett water supply well (CWSW), which is located over the FS-28 plume and is separated vertically by approximately 100 feet of clean water. She noted that the CWSW also is protected by a carbon filtration system, which the Air Force Center for Environmental Excellence (AFCEE) installed in 1996.

Ms. Foster reported that the cleanup objectives were focused on two goals: to prevent and reduce exposure to human health and the environment, and to restore the aquifer to beneficial uses within a reasonable timeframe. With those two goals in mind, seven alternatives were addressed in the feasibility study, and four of those alternatives were considered further.

Ms. Foster reported that Alternative 1 is a no-action alternative, which is retained for comparative purposes. She reported that Alternative 3 involves maintaining the existing systems, which are predicted to capture 99% of the mass of the plume within an estimated 18 years. She also reported that Alternatives 6 and 7 address restoring the aquifer in a quicker timeframe by aggressively treating the northern part of the plume. She noted that Alternative 6 would include the design and construction of an approximately 600 gallons per minute (gpm) system north of Coonamessett Pond, in the Lochstead Estates area. She explained that the treated water would be reintroduced to the aquifer through approximately three wells. Ms. Foster noted that the wellfield layout on the map is conceptual, and further investigation and design would determine the exact wellfield layout and the location of the treatment plant.

Ms. Foster reported that the Air Force prefers Alternative 7, which involves continuing the existing system and building an additional system that is intended to cut the plume in half, thereby cutting the restoration timeframe in half. The trailing part of the plume would be cut off by approximately three extraction wells, and the treated water would be reinjected to the Coonamessett pond and/or the Coonamessett river. Ms. Foster stated that this alternative is expected to cut the aquifer restoration timeframe from approximately 18 years to approximately 9 years.

Ms. Foster stated that there are serious considerations regarding the implementation of Alternative 7, such as environmental impacts and property access issues. She noted that there is a concern with the upper reach of the Coonamessett River and the Souza Conservation Area. Ms. Foster displayed a summary of the FS-28 alternatives.

Questions and Answers

Ms. Valiela asked if it is correct that Alternative 7 includes a 600-gpm extraction in addition to EW-1. Ms. Foster indicated that this is correct.

FS-29

Ms. Foster displayed a map of the FS-29 plume and noted that the nature and extent of contamination in the FS-29 plume, which was discovered in 1998, is not as well understood as the FS-28 plume. She reported that there are approximately nine data collection wells in FS-29, and more information will have to be gathered to ensure that the selected alternative is appropriate.

Ms. Foster reported that there is a selected remedy for the Chemical Spill 21 (CS-21) plume, and AFCEE and Jacobs Engineering will be collecting additional data in the CS-20 and CS-21 area, and designing and building a treatment system for the CS-21 plume that will capture an estimated 23% of the FS-29 plume. She noted that the CS-21 and FS-29 plumes intersect north of Route 151. Ms. Foster reported that there is no current risk to human health from the FS-29 plume because all of the residences in the area are connected to municipal water. She also noted that a cleanup objective for the FS-29 plume is to restore the aquifer to its beneficial uses within a reasonable timeframe.

Ms. Foster reported that the Air Force has focused on four remedial alternatives for FS-29. Alternative 1 is a no-action alternative, retained for comparison purposes. Alternative 2 relies on institutional and engineering controls, together with long-term monitoring, to ensure that human health is protected and that the plume does not continue to migrate beyond its current extent. Ms. Foster noted that AFCEE’s limited understanding of the FS-29 plume is that the concentrations are low enough that the plume is not expanding and, will be restored to cleanup goals after 13 years.

Ms. Foster reported that Alternatives 3 and 7 involve extraction, treatment, and reinjection. She displayed a map of the conceptual wellfield layout for Alternative 3, which includes a 600 gpm system, and noted that it is hoped that Alternative 3 would capture all of the FS-29 plume. She then displayed a map of the conceptual wellfield layout for Alternative 7, AFCEE’s preferred alternative, and noted that it relies on natural processes, which are believed to be diluting the aquifer in the toe of the plume. She stated that the focus of Alternative 7 would be on the central portion of the FS-29 plume, which would restore the aquifer in this area to the cleanup goals within approximately six years. Ms. Foster then displayed a summary of the FS-29 alternatives.

Agenda Item #3. Question and Answer Period

Mr. Karson asked if there were any questions about Ms. Foster’s presentation. He noted that any questions or comments posed now will be addressed, but will not become part of the official transcript. Comments made later during the formal hearing will become part of the official transcript.

A member of the audience stated that it appears that since a plan has not been developed to address the CS-21 plume, the Air Force is further ahead on addressing FS-29. Ms. Foster replied that the public comment period for the CS-21, CS-20, CS-4, and FS-13 plumes occurred last summer; therefore, the Air Force is further along in the process for those plumes than for the FS-28 and FS-29 plumes. The audience member then asked if it is correct that the design phase is further along. Mr. Karson explained that the record of decision (ROD) for those plumes has been signed. The next step is the engineering and design phase, which will be followed by the construction phase. Mr. Karson noted that the treatment system for CS-21 and the other solvent plumes in that area should be fully designed by the end of this year.

A member of the audience asked Ms. Foster for her opinion on what should be done and why. Mr. Karson explained that AFCEE’s preferred alternatives came out of joint discussions involving AFCEE, the regulatory agencies, and Jacobs Engineering.

Agenda Item #4. Adjourn

Mr. Karson adjourned the meeting at 6:39 PM. A formal public hearing was then conducted. The transcript of that hearing will be part of the Responsiveness Summary and available at a later date.