Meeting Minutes

Agenda Item #1. Welcome, Introductions and Groundrules

Mr. Field convened the meeting at 6:30 PM and explained that the purpose of this meeting is to provide an update on the Fuel Spill 28 (FS-28) and FS-29 plumes. He briefly reviewed the meeting groundrules and the agenda, and noted that representatives from the Massachusetts Department of Environmental Protection (MA DEP), the United States Environmental Protection Agency (EPA), and the Air Force Center for Environmental Excellence (AFCEE) were present.

Agenda Item #2. What is a plume?

Mr. Karson displayed a diagram of the groundwater recharge process (See attachment #1, which includes all slides shown during this presentation). He explained that precipitation, in the form of rain or snow, falls to the ground, percolates through the sandy soil and eventually reaches a point, which could be anywhere from 30 to 60 feet below ground surface, where all the air spaces between the sand particles are filled with water. That 250-foot thickness, where the sand is saturated with water, is the groundwater aquifer. Mr. Karson explained that the groundwater on upper Cape Cod is always moving – it basically is rolling off of a big hill and moving toward water bodies such as rivers, ponds, or the ocean.

Mr. Karson displayed a map of the Sagamore Lens and explained that the Sagamore Lens is a body of groundwater that extends from the Cape Cod Canal down to Falmouth, and eastward to Bass River in Yarmouth. The Sagamore Lens provides drinking water for the upper Cape and much of Barnstable. He stated that the thickest amount of groundwater within the Sagamore Lens is located at the highest point, which is approximately 60 feet above sea level. He noted that groundwater flows perpendicular to the contour lines shown on the map. Mr. Karson also noted that most of the industrial-type activities that occurred at the gas stations, the motor pools, the landfills, and so forth, were located in the southern portion of the military base; the groundwater plumes that formed as a result of this contamination getting into the soil have moved and affected mostly Falmouth, Mashpee, Bourne and Sandwich.

Mr. Karson then displayed a slide titled "Hydrogeological Conceptual Model." He explained that a source area is an area where materials such as solvents or fuels were disposed of or spilled. Those materials enter the soil, eventually mix with rainwater, dissolve into the water, and percolate down into the saturated area. When the materials reach the saturated area, they spread out and become thicker and wider, and in some cases, up to two miles long, based on the travel rate of two feet per day and that many of the source areas have been feeding the plumes for decades. He explained that the diagram shows that plumes do move, and over time can become disconnected from their source areas, which is the case with the FS-28 and FS-29 plumes.

Mr. Karson reported that the primary contaminant in the FS-28 and FS-29 plumes is ethylene dibromide (EDB). He explained that EDB is a chemical that was added to aviation gasoline, which was used at the base for many years.

Agenda Item #3. AFCEE Policy on Town Water Connections

Mr. Karson displayed a map and stated that since 1991 the Air Force has been evaluating groundwater quality in Hatchville. He stated that in 1991 approximately 20 homes were tested along Boxberry Hill Road. Since that time, the testing has been expanded and the Air Force now has a good understanding of the quality of drinking water in private wells in the Hatchville area. He stated that the investigation to define this area, in terms of contamination, has been ongoing and has included the installation of approximately 100 wells to define the contaminant plumes.

Mr. Karson stated that one of the issues that the Air Force addresses is town water conversions. He explained that the Air Force determines whether or not an area is eligible for a town water connection based on two types of distances – crossgradient distance and downgradient distance. Mr. Karson noted, for example, that anyone who resides within a crossgradient distance of 500 feet from the FS-29 plume, which is what the Air Force uses as a starting evaluation, would automatically become eligible for town water connection. The second type of distance taken into consideration is the downgradient distance from a plume. He reiterated that the contamination is dissolved in groundwater, which is constantly moving at a rate of two feet per day. The Air Force projects out over a two-year period, which calculates to approximately 1500 feet, and maps out where the plumes would be in that amount of time. Mr. Karson explained that the two-year window allows for the identification of private wells and the ability to provide municipal or town water within that two-year window, should those private wells be threatened, based on this analysis. He pointed out on the map the area where the Air Force has recently paid for town water connections. He reported that the earliest agreement, which dates back two and a half years ago, involved homes in the area of Hatchville Road, Wellington Way, Raspberry Path, and Ranch Road. He noted that additional homes along Boxberry Hill Road and Cloverfield Way have been added.

Mr. Karson stated that there has been a lot of interest regarding the Air Force’s intentions for the possibility of additional town water connections. He noted that up until 11 days ago, based on the current cleanup activities for the northern plumes, spending money on town water connections did not seem warranted because the plumes would be captured. Within the last ten days, however, the Air Force has received guidance to open a dialogue with the Town of Falmouth to explore the possibility of providing some funding to the town. At a meeting last Friday, the Air Force and town officials discussed the area bounded by Hatchville Road, down to Sam Turner Road, and northward to Route 151 and Boxberry Hill Road. Mr. Karson also reported that all properties located within the "triangle area" that are still on private well systems are now on the table for discussion for town water connections. He noted that the details of this plan will be developed in further discussions and formal negotiations. He stated that the Air Force has not yet entered into formal negotiations with the Town of Falmouth, and explained that the purpose of last Friday’s meeting was to inform the Town of Falmouth that the Air Force has received direction that the "door is now open" to having negotiations with the town.

Mr. Karson stated that he is not indicating that there will definitely be 100% funding from the Air Force – the entire area will be considered. The Air Force will evaluate factors such as the cost to continue private well sampling twice a year and what will happen in two years when the systems for the chemical spill plumes to the north are in place and pumping and treating water. Mr. Karson stated that it is the Air Force’s intent to reach resolution, and it is hoped that that will be the provision of town water to everyone in the area delineated, at minimal cost to the town and the residents in that area.

Agenda Item #4. Discussion

Mr. Dow noted that the Town of Falmouth has a public water supply well at Coonamessett Pond and is starting to develop a public water supply well at Crooked Pond. He asked if those two town wells would influence the plumes, causing them to arrive sooner than the projections in the buffer area. He commented that he would assume that the rate at which those town wells are pumped could have an influence on the general hydrology in that area. Mr. Witzmann replied that the Coonamessett Pond well lies right above the FS-28 plume, so no influence on that plume is expected from the Coonamessett Pond well. He also stated that the Crooked Pond well will have an influence, but probably over a longer term. Mr. Karson added that it is important to consider that within the next two and a half years, design and construction efforts for Chemical Spill 4 (CS-4), CS-20, and CS-21 will effectively keep those plumes from moving further south, thereby preventing them from affecting the proposed downgradient well at Crooked Pond.

Ms. Foster, with Jacobs Engineering, added that the pumping rates at which those municipal water supply wells would extract water would cause a radius of influence of about 1000 feet; outside of that 1000 feet, a difference would not be seen. She explained that if the CS-20 plume were to come within 600 feet of the Crooked Pond well, some acceleration of groundwater might be seen; it is not believed, however, that the CS-20 plume would get that far, if left uncaptured.

Mr. Harry Foster referred to the slide titled "Hydrogeological Conceptual Model" and asked Mr. Karson to explain the fourth and fifth panels. Mr. Karson explained that those panels depict the dissolved contamination in groundwater. He further explained that in addition to the sandy soils, there are confining layers, such as silt or clay; as the contamination comes into contact with those layers, portions of the contamination can adhere to the silty materials and basically become immobilized, while the bulk of the groundwater continues to flow away with the plume. Mr. Foster inquired about the fate of those residuals. Mr. Karson replied that over time, the residuals probably degrade and remain immobile.

Mr. Rand inquired about the level of effort that would be applied to treatment of the CS-20 plume should the Air Force fully or partially fund town water connections to the Hatchville area downgradient of the CS-20 plume. Mr. Karson replied that the Air Force’s proposal, which was recently put out for public comment, called for in-plume treatment – the Air Force’s position has not changed, it is still proposing in-plume treatment. He reported that a formal Record of Decision (ROD) is scheduled to be issued to announce that the Air Force will go forward with construction, and this recent development to consider more town water hookups is additional. He stated that the Air Force has been asked to try to resolve the concerns in this area for future water supplies. Mr. Karson stated that the Air Force does consider the effect of these systems, and added that the modeling indicates that once these wells are in place in each of the solvent plumes, the plumes will be captured.

Mr. Rand commented that his concern is that if town water is provided, no effort will be made to treat the CS-20 plume, which would then contaminate the pond. Mr. Karson assured him that that is not the Air Force’s intention.

Mr. Kanter asked if the rate of travel of the FS-28 plume is the same as the other plumes. Mr. Karson replied that it is – approximately two feet per day. Mr. Kanter then asked if the plumes would continue to travel and not stop somewhere along the way if no further actions are taken. Mr. Karson referred to the map and pointed out that the FS-28 and FS-29 plumes, as well as the chemical spill plumes, are drawn with rounded edges at the top, which is a result of the investigation. He explained that through the investigation, the Air Force backtracked to define the plumes, and he pointed to the area where wells were installed and evidence of FS-28 was no longer being seen. He noted that the plumes are no longer connected to their source areas. Mr. Karson stated that over time, perhaps over decades, the plumes in "this immediate area" would follow the same path of the FS-28 plume down to the discharge point, which is the Coonamessett River. The plumes off to the west would travel in a southwesterly direction, eventually toward the ocean.

Ms. Lauren Foster added that the groundwater occupied by these plumes will continue to migrate to the ocean; however, the leading edges of these plumes are more dilute then the main bodies of the plumes. She explained that when plumes become very dilute, the contaminants in the plume continue on their path with the groundwater, and there comes a point where the dilution overtakes the rate of migration. She referred to the conceptual model and stated that the plumes will not continue to move as a detached slug of contamination to the ocean – at a certain point dilution, degradation, and dispersion will take over and the plumes might not actually get that far. Ms. Foster noted that Jacobs Engineering has brought to this meeting some of the animation tools used to evaluate how the contaminants move in the groundwater. She invited anyone interested in viewing the animations to do so after the meeting.

Mr. Murphy inquired about the depth of the pollution and the depth of the private wells in the FS-28 and FS-29 area. Mr. Karson replied that in most cases private wells are shallower than the contaminant plumes within the aquifer.

Mr. Murphy inquired about the timeframe for negotiations with the Town of Falmouth regarding an agreement on the town water connections. Mr. Karson replied that presently the Air Force has approximately six separate agreements with the Town of Falmouth, some of which happened within a few weeks, some over months. This particular case involves over 100 homes in a large area, and it will entail a large construction project to lay all the water mains and make the connections.

Mr. Minior added that it does not take a long period of time to negotiate something like this. He stated that if it is a cost-shared proposal, the Selectmen would have to vote on accepting the proposal and the question would be whether the town picks up the remainder of the cost, or the residents and the town assume the remainder of the cost. He said that if it were a capital improvement project, the question would be whether it would have to go to town meeting. He said that while agreement might be reached, it may take a little longer to effect all the final details if a vote at town meeting is required. Mr. Minior added that with the proposals being considered, even if it were to take a year to negotiate and reach and sign an agreement, the plumes have not advanced far enough to cause any impact to the neighborhood. Mr. Karson added that until all the connections were completed, the Air Force would continue to offer semi-annual private well testing to area residents.

Mr. Murphy then read a petition regarding municipal water connections in the "triangle area" as follows: "This petition represents the unity of our neighborhood, Goeletta Drive, Brigateen Drive, Bark Drive, Caravell Drive, Cutter Drive, and Gallion Drive in Hatchville, in requesting the immediate installation of water mains to connect our homes to the town water supply. This action is necessary in order to provide a safe, non-contaminated water source for all the residents of our neighborhood, and to protect our health, safety, and psychological well being. The FS-29 and CS-21 plumes pass to the northwest of the neighborhood. The FS-28 plume passes to the east. The CS-20 and CS-4 plumes are heading directly toward this area from the north side of Route 151. The fact that town water is in the process of being installed on portions of Goeletta Drive and Caravell Drive indicates that the FS-29 plume has taken an unexpected shift in our direction, illustrating how difficult it is to predict the progress of plumes through the water table. As a result, the water supply for this neighborhood is threatened with contamination and in fact may already be polluted. We the undersigned residents urge the board of selectmen to initiate plans to install water mains to the remaining homes in the streets named above. We also urge that during the planning of this installation bi-weekly testing be done and that bottled water is made available at resident’s request. We also urge the placement of monitoring wells at appropriate locations around the neighborhood mentioned, so as to provide early detection of any plume material." Mr. Murphy noted that 135 residents have signed the petition.

Mr. Murphy commented that he is also concerned about the homes and families located between Sam Turner Road and Deep Pond. He said that he spoke with a representative of the MassDEP and indicated that in his estimation, there are not sufficient testing wells to determine where the edge of the plume is. Mr. Murphy remarked that while he understands that this is not an exacting science, and he trusts the process, it seems to him that there are a lot of residents at risk in this area and the Air Force is not able to truly test where the contaminant plume is headed.

Mr. Karson replied that there are a lot of monitoring wells, and he pointed out their locations on the map, including a couple of wells near Deep Pond and one at Braeburn Court. He explained that monitoring well locations are based on what is upgradient, the groundwater flow, and computer modeling that indicates where the plumes are expected to be located. Mr. Karson stated that the private wells in this area typically are shallower than the contamination seen in the FS-29 plume. He explained that the FS-29 plume is a fairly deep plume over which there is a lot of clean water, so nearby private wells are actually on top of the FS-29 plume. He stated that the twice-a-year sampling program, which is offered to residences in this area, indicates that the private wells are not drawing up the FS-29 plume. He reported that the potential need to increase sampling frequency will be discussed with the town officials once the negotiation process begins. Mr. Karson also noted that the question of how long it will take to complete town water connections and whether the sampling program is sufficient in the interim to be protective of public health will be decided in consultation with the public health agencies.

Mr. Murphy asked if private wells located closer to the plume and its buffer will be tested more frequently than private wells located farther away. Mr. Karson replied that the decision to test wells more frequently would be made in consultation with the Massachusetts Department of Public Health (MDPH), the EPA, the MassDEP and the town Board of Health. As an example, he mentioned that two private wells on Cloverfield Way had measurable detections of trichloroethylene (TCE), which were evident through the sampling program. It was known that the plume went underneath those properties and that some of those wells were deeper than typical private wells seen in this area; in consultation with the regulatory agencies, the decision was made to do bi-weekly testing and to provide bottled water as a precaution. This response was undertaken despite that the levels of TCE detected were very low and were considered safe to drink. Mr. Karson stated whether there is a risk, based on current available information, will be considered for portions of this area to determine if actions are warranted. Mr. Karson added that he could not commit to this tonight without consulting with the regulatory and public health agencies.

Mr. Reed asked how much EDB is in the leading edge of the FS-28 plume, and where the "broken-off" portion of the FS-28 plume is going. Mr. Karson recommended that these questions be deferred until the next presentation this evening, which will address those issues.

Ms. Angel inquired about the depth of the private wells on Cloverfield Way. Mr. Karson replied that the depth below ground surface for some of the wells is about 120 feet, and 50 feet to the water table. He noted that those wells reached the water table and continued for another 60 to 70 feet, which is deeper than typical private wells.

Agenda Item #5. Fuel Spill 28 and 29 Groundwater Plumes

Mr. Witzmann displayed a map and stated that the FS-28 and FS-29 plumes are part of the Southwest Operable Unit (SWOU), which is outlined in red on the map. He stated that the FS-29 plume is a dilute plume, and reported that the two contaminants of concern in this plume are EDB and carbon tetrachloride. He noted that EDB has been detected in the FS-29 plume at a maximum of 0.108 parts per billion (ppb), which is about five or six times the drinking water standard, and carbon tetrachloride has been detected at a maximum of 9.5 ppb, which is about twice the drinking water standard.

Mr. Witzmann noted that in the uppermost area the FS-29 and CS-21 plumes overlap. He pointed out the area that is about 70 feet down to the top of the aquifer and about another 70 feet between the top of the aquifer and the top of the plume. He stated that the plume has two lobes running one right on top of the other; each of the lobes range from 20 to 50 feet in depth and there is approximately 20 to 70 feet of clean water in between the lobes.

Mr. Witzmann reported that the maximum detection of EDB in the FS-28 plume is 18 ppb, which is almost 100 times as high as the maximum detection in the FS-29 plume. He stated that the trailing edge of FS-28 is quite dilute and as it moves farther to the south, the concentrations tend to increase. Mr. Witzmann also reported that 85% of the EDB is located south of the western arm of Coonamessett Pond. He pointed to an area on the map and explained that as the groundwater moves down through that area, the plume moves to the south, but then upwells as it approaches the Coonamessett River. He noted that the outlines shown on the map depict the portions of the aquifer where the concentrations are above drinking water standards.

Mr. Witzmann reported that in response to the FS-28 and FS-29 plumes, the Air Force, the EPA, and the MassDEP have developed four remedial action alternatives. He then reviewed the overriding goals for the cleanup. The first objective calls for the prevention or reduction of residential exposure to contaminants of concern above drinking water standards in groundwater. Mr. Witzmann noted that the drinking water standard is 0.02 ppb for EDB and 5 ppb for carbon tetrachloride. The other objectives are to restore the aquifer to its beneficial uses within a reasonable timeframe, to prevent worker contact and child and adult water contact with Coonamessett River water containing unacceptable concentrations of EDB (FS-28 plume only), and to prevent the ingestion of fish exposed to Coonamessett River water containing unacceptable concentrations of EDB (FS-28 plume only).

Mr. Witzmann stated that it is early in the decision-making process for the FS-28 and FS-29 plumes. He reported that a draft Feasibility Study was released in July 1999, and the Air Force is currently working with the regulators to resolve comments on the Feasibility Study. He explained that feasibility study looks at a wide range of technologies and from that a series of alternatives is developed. Those alternatives are then evaluated based on a number of criteria. Mr. Witzmann stated that the details of how the alternatives compare to one another will be provided once the regulators and the Air Force reach agreement on the evaluation of those alternatives. He also reported that the next scheduled public meeting is scheduled for January 5, 2000, at which time the Air Force will announce its Proposed Plan to address the FS-28 and FS-29 plumes. He noted that the public comment period on the Proposed Plan will run from January 6 to February 4, 2000, and the ROD is scheduled to be signed on July 28, 2000.

Mr. Witzmann stated that the three proposed remedial alternatives for the FS-28 plume that received detailed analysis were: Alternative 3: continued operation of the existing treatment systems; Alternative 6: continued remedial operations with additional extraction, treatment and reinjection at Coonamessett Circle and; Alternative 7: continued remedial operations with additional extraction and treatment in the Souza Conservation Area.

Mr. Witzmann displayed a map of Alternative 3, and reported that to date a number of actions have been taken in response to the FS-28 plume. These actions include water hookups for the residences above and adjacent to the plume, and the construction of a treatment system at the Coonamessett water supply well, which is physically located above the plume. He then stated that the purpose of the extraction well 1 (EW-1) treatment system is to capture the highest concentrations of contamination. This year a shallow well-point extraction system was added to the EW-1 treatment system. He explained that as the plume moves down to the south, it is also upwelling. The combination of the EW-1 system and the shallow well-point system seems to be acting as a containment system, in that contamination does not seem to be making it past the systems.

Mr. Witzmann reported that since May 1999, no contamination has been detected in the Coonamessett River. He noted that there is a small portion of contamination farther downgradient, which is estimated to be approximately three tenths of 1% of the total plume mass, and which does not seem to be upwelling into the river at detectable concentrations. Mr. Witzmann added that if additional treatment were pursued north of the existing systems, over the long term the combined systems would not capture any additional EDB, because it would all eventually be captured to the south. At the same time; however, these systems rely on the flow of groundwater to the south – so if restoration of the aquifer in this area is to be expedited, it is necessary to pursue additional treatment.

Mr. Witzmann explained that the existing systems prevent exposure to plume contaminants, both residential and in the river, and the purpose of the additional alternatives being considered is to expedite the restoration of the aquifer.

Mr. Witzmann displayed a map of Alternative 6 and stated that it involves five extraction wells pumping a total of approximately 600 gallons per minute (gpm) around Coonamessett Circle. He stated that the water would be treated with granular activated carbon and the clean water would be reinjected north of the pond. He noted that a benefit of this alternative is early restoration of the aquifer, and a downfall of this alternative is the construction in residential neighborhoods.

Mr. Witzmann displayed a map of Alternative 7, which involves three extraction wells located south of Coonamessett Pond, pumping about 600 gpm. The water would be treated with granular activated carbon. He stated that the combination of those three wells and the Coonamessett water supply well would tend to drawdown the water table in this area. He noted that the Coonamessett River also flows through this area and pointed out a portion of the river would dry up if the treated water were not discharged to the pond or the river. He explained that the alternative therefore includes discharge to either the Coonamessett River or the Coonamessett Pond, or some combination of both.

Mr. Witzmann listed the four FS-29 plume alternatives, which received detailed analysis: no remedial action with long term monitoring; institutional and engineering controls; extraction, treatment and reinjection for plume capture; and extraction, treatment and reinjection to capture the central portion of the FS-29 plume.

Mr. Witzmann stated that there is an area within the FS-29 plume that overlaps the CS-21 plume, and reported that the Air Force has previously proposed treatment for the CS-21 plume. He pointed out the portion of the FS-29 plume that the CS-21 plume treatment system will capture, and noted that it would leave the distal end and the central portion of the plume uncaptured. He reported that one of the proposed active systems would capture both the distal end and the central portion of the plume, and the other active system would capture the central portion only, with the distal end of the plume continuing to travel along with the groundwater. Mr. Witzmann explained that the purpose of the alternative that only captures the central portion of the plume is to provide additional protection for the potential water supply well site that the Town of Falmouth is considering.

Mr. Witzmann explained that the institutional and engineering controls alternative would monitor the plume, and would involve controls placed by the Town of Falmouth on the residents to limit groundwater use in order to protect them from plume contaminants. He then pointed out the well for which the alternative also would include a specific treatment system.

Mr. Witzmann reported that between now and January 2000, AFCEE will develop a Proposed Plan to address these plumes. At that time the Proposed Plan will be released and followed by a formal comment period, when the residents and stakeholders will have the opportunity to comment on the plan.

Agenda Item #7. Discussion

Mr. Reed asked if it is correct that 85% of the contamination is in the leading edge of the FS-29 plume. Mr. Witzmann replied that this is correct. Mr. Reed commented that the leading edge of the FS-29 plume has taken a right-hand turn into the Coonamessett River. He then asked where the broken-off section of the plume is going, and what will happen to it. Mr. Witzmann replied that currently no treatment has been proposed for that section of the plume. He stated that the broken-off portion of the FS-29 plume is well under 1% of the total plume mass, and added that it is most significant that no EDB is currently being detected in the river. Mr. Reed said that he is concerned because although the broken-off portion of the plume is 1% of the plume mass, it is 85% of the contamination. Mr. Witzmann clarified that the portion of the plume that is escaping capture is about three tenths of 1%. He further clarified by pointing out the portion of the plume to which the 85% refers, and the portion of the plume that makes up the three tenths of 1%..

Mr. Reed asked if the plume is moving at a rate of two feet per day. Mr. Witzmann replied that it is. Mr. Reed then asked where the plume is going. Mr. Witzmann displayed a cross-section of the plume that shows the piece of the plume that has broken-off. He noted that as the plume moves downgradient, it is upwelling. He then identified on the map the shallow well-points and the "broken-off" section of the plume. Mr. Reed asked how much EDB is contained in the broken-off section of the plume, and where that section is going. Mr. Witzmann replied that the broken-off portion of the plume is slowly moving toward the river. He added that this is an area where water from all sides of the river flows up and into the river, and this convergence seems to be bringing enough water with it that the EDB is at undetectable concentrations in the river.

Ms. Litvin commented that Alternatives 4 and 5, which were not discussed, also involve Coonamessett Circle. She then asked if those alternatives were abandoned as potential alternatives. Mr. Witzmann replied that during the Feasibility Study process, two levels of analysis are conducted for the alternatives. Alternatives 4 and 5 were dropped out at the first level, which is the screening level. He explained that the alternatives discussed tonight are those that made it to the next step, which is detailed analysis. Mr. Witzmann stated that Alternatives 4 and 5, which included more extensive construction around Coonamessett Circle, did not make it to the next step; however, there is nothing to prevent any of the involved parties from coming back and saying "we would like to do this." Ms. Litvin asked if it is correct that Alternatives 4 and 5 are still subject to consideration if the EPA or the MassDEP require that of the Air Force. Mr. Witzmann replied that this is correct.

Ms. Litvin said that she believes that Alternatives 4 and 5 did not make it to the second level for reasons that she thinks are equally compelling for Alternative 6. She commented that it seems to her that everything that was wrong with Alternatives 4 and 5, other than the degree of construction, is wrong with Alternative 6. She then asked why Alternative 6 has made it this far in the process. Mr. Karson replied that this issue will be discussed in the resolution of the Feasibility Study. He explained that a couple of alternatives are being considered and the goal is to reach consensus with the regulatory agencies on whether one of those alternatives will be proposed come January 2000, or whether previous alternatives should be re-evaluated. Mr. Karson stated that there is always room for flexibility in this program, as evidenced by several of the plume projects that have gone through this type of process. He explained that while there is some variability, Mr. Witzmann is discussing alternatives that are currently being considered and evaluated – three alternatives are currently being considered for this plume. The alternatives that have not made it to this step are not being aggressively considered.

Ms. Litvin asked why Alternative 6 is not thought to be equally as bad as Alternatives 4 and 5, such that it is still on the table for consideration. Mr. Witzmann replied that Alternative 6 involves considerably less construction than Alternatives 4 and 5. He explained that Alternative 4 includes 20 extraction wells and 20 reinjection wells, which would require a lot of construction. He also noted that Alternative 5 includes 10 or 12 extraction wells, and 10 reinjection wells a little further to the south. Mr. Litvin said that she understands, but noted that Alternatives 4, 5, and 6 all involve private property. Mr. Witzmann stated that although all three alternatives involve construction in the area, Alternatives 4 and 5 involve significantly more construction, and the modeling indicates that they do not perform as well as the other alternatives.

Ms. Litvin asked why Alternatives 4 and 5 would not perform as well as the other alternatives. Ms Lauren Foster explained that the intent of Alternatives 4, 5, and 6, was to cut the plume in half – the southern half of the plume would detach and be captured by the southern system, and the trailing edge of the plume would be captured by Alternative 4, 5, 6, or 7. She stated that when the alternatives were modeled, it was determined that more wells did not necessarily mean more capture. She explained that when fewer wells were used with higher extraction rates, they captured more mass than the more extravagant systems that used many wells.

Ms. MacRae asked what happens to the treatment plants during a power outage. Mr. Witzmann replied that during a power outage the systems would shut down. Mr. MacRae asked if it is then correct that the river would no longer be free of EDB. Mr. Witzmann explained that there is a radius of capture – if the systems shut down for a short period of time and then restart, no EDB would make it past the system. Ms. MacRae asked what would happen if the power were out for a few days. Ms. Foster explained that if a parcel of groundwater is moving toward an extraction well, EW-1 for example, and the extraction well is not pumping, the groundwater parcel will move past the system. She further explained that EW-1 pulls water from all around it, not just from upstream – so in theory, the parcel of water would go by the well. It would take over a week, maybe over a month, however, before the water parcel got so far that if the well were turned on, it would not come back to the well.

Ms. MacRae stated that Ocean Spray has indicated that it would not take the cranberries unless the river is EDB-free, and it sounds to her as though the river will never be EDB-free. Mr. Field noted that Ms. MacRae is concerned about power outages and the possibility that a well would not be started soon enough to prevent a slug move toward the river, which would result in contamination in the river despite best efforts. Ms. Foster stated that if power were lost for a very long period of time, or if, theoretically, the Air Force decided to stop its efforts, the river would become contaminated again. Mr. Karson added that it is a possibility, but it is extremely unlikely, based on the Air Force’s commitment to maintain the system. He agreed that power outages occur, as was the case several weeks ago. There is a window of opportunity, however, to get those systems back online and continue treatment, and avoid the negative effect of EDB being detected in the river system. He stated that if there are long-term power outages, portable generators could be considered as an interim solution.

Ms. MacRae expressed concern about the consumption of potentially contaminated fish in the Coonamessett River. She then stated that she lives on the Coonamessett River and has requested that signs be posted at the river to advise against fish consumption, and this has not yet been done. She stated that this year she witnessed a lawn company drawing water from the river to fertilize someone’s lawn. Ms. MacRae remarked that she sees people on the cranberry bogs picking the cranberries, and now there is a concern about the consumption of fish. She questioned how a child who catches a fish in this river would know that there could be a level of EDB in the fish. Ms. MacRae asked why signs are not posted at the bogs. Mr. Karson replied that the public health agencies, the town, and the MDPH would collectively make the decision to post signs at the river advising against fish consumption. Ms. MacRae reiterated that there are lawn companies taking water from the Coonamessett River. Ms. Karson stated that since the systems were started in April 1999, all the sampling results from all nine locations along the Coonamessett River have been nondetect for EDB, which is a direct result of EW-1 and the shallow well-point extraction wells in that area.

Ms. MacRae inquired about the portion of the plume that has gone through the river. Mr. Karson replied that this is a very small, very dilute portion of the plume. Modeling indicates that when it does discharge to the river, if it has not already done so, the plume would never be detectable in the river water due to the small quantity of contamination and its dilute nature. He stated that this will be substantiated and proven through the continued testing of the river – if conditions change, then the system will need to be adjusted.

Ms. MacRae again noted that she lives on the Coonamessett River, and she sees many things of which most people are not aware. She reiterated that lawn companies pump water from the Coonamessett River into their trucks to fertilize lawns in other neighborhoods and she finds this appalling. Mr. Field suggested, given Ms. MacRae’s concerns about activities of which the Air Force might not be aware, that the Remedial Project Managers (RPMs) from EPA, MassDEP and AFCEE consult the MDPH regarding this issue.

Mr. Dow commented that it is not obvious that the shallow-point wells would be able to pull back contamination if the power goes down. Mr. Witzmann stated that the zone of capture for the well-points is smaller, and so that period of time would be shorter.

Mr. Dow then asked how thallium, which is above safe drinking water levels in the FS-29 plume, will be addressed. He added that it is not obvious to him that the extraction, treatment, and reinjection (ETR) systems will address the thallium. Mr. Witzmann replied that there are a number of inorganics present in the groundwater here, including thallium, iron, and manganese. He explained that these inorganics are very different in the way they react compared to the contaminants being discussed, which are EDB and carbon tetrachloride. He explained that the inorganics tend to change their oxidation state. If there were fuel contamination in the aquifer, for example, and the fuel degraded, all of the oxygen would be "sucked out" of the aquifer during the degradation process. Because of those chemical changes, the oxidation state of those metals also would change, which would affect the mobility of the metals. Mr. Witzmann stated that to treat thallium is not necessarily a question of whether or not it is there – thallium can be addressed without it being removed.

Ms. Lauren Foster added that thallium has been detected sporadically in the SWOU, at concentrations above the drinking water standard. The plumes being discussed tonight, however, are not thallium plumes. She stated that the distribution of thallium within the SWOU is random in that it is not in one particular plume in one particular area. She added that thallium does not move in the same way as the plumes and it is not believed to be attributable to base waste practices. Ms. Foster further stated that the concentrations of thallium seen in the SWOU groundwater are consistent with background groundwater concentrations. She then stated that there is a requirement to treat to a drinkable quality all extracted groundwater that will be discharged – water containing unacceptable concentrations of thallium would not be discharged.

Mr. Dow said that he disagrees that thallium is at background because it is above drinking water standards, and is not something that occurs naturally unless there are appropriate minerals, which he does not believe to be the case. He commented that to depend on changes of the oxygen concentrations in the plumes to control the thallium is "lame" in his view.

Mr. Doust remarked that there has been no mention of the basis of modeling, and that it is not exact. He stated that a lot of the pictures shown this evening have "nice straight even lines," and there have been a lot of statements made about numbers, and he is not comfortable with this. Mr. Doust said that he does modeling for a living, and even with his own modeling, he is not confident all the time. He said that these are large scale problems being modeled and the lines are "too neat" for him. He suggested that the public be provided with an explanation that modeling is not exact and that the plume outlines being shown are not exact because they are based on models. Mr. Doust stated that he did not believe that the members of the public who look at the models and graphic simulations should be comfortable in believing that this is exactly what will happen.

Mr. Witzmann agreed with the comment on modeling, but also pointed out that the outlines shown on the map are based on actual groundwater data from samples that have been collected. He stated that there are many cases where it is questionable how to draw an outline – for example, exactly how to draw the trailing edge of the FS-28 plume because it contains a considerable amount of clean water. Generally, and in that case in particular, the plume has been drawn larger than it actually is, in order to account for the contamination that is there, despite the fact that it also contains clean water. Mr. Witzmann stated that comments such as, "this system will clean up this plume in ten years," are based on modeling, and there is definitely a lot of uncertainty, both in terms of what is out there at the present moment and how the system will react with the aquifer. Mr. Doust stated that this is part of his reasoning for his objection – it is being said that "it is going to happen," rather than "it is likely to happen." He stated that the data is only a coarse number of points, yet there is a fine resolution shown on the map for these plots. He said that what is occurring between two points is totally different than the straight line drawn between those points.

Ms. Canosa inquired about the proposed wells to be installed in the Lochstead are and how they would affect the water there. Mr. Witzmann explained that the aquifer is beneath the unsaturated soil, and the plume begins between 70 to 90 feet down in the aquifer, underneath 70 to 90 feet of clean water. He said that the proposal includes installing an extraction well to pump the contaminated water, which will remove the contamination from the aquifer, and will draw down the water table, thereby causing more water to flow in behind it. Ms. Canosa asked if that would raise the contamination into the clean water area. Mr. Witzmann replied that it would not, and explained that while it would pull in the contamination, contamination is already in the area down at the bedrock level, so there would be no mixing of contaminated water and clean water that is not already occurring.

Ms. Canosa asked if disturbing that area could result in a chemical change to the clean water. Mr. Witzmann replied that it could, but added that the contaminant being discussed, EDB, is not very reactive. Mr. Field asked if it is correct that when an extraction well is installed to clean a certain depth of water, an attempt is made to avoid mixing with other clean layers, thereby not disturbing the entire water column. Mr. Witzmann replied that this is correct.

Ms. Canosa commented that she has a hard time understanding how the clean water is not contaminated if water is distributed through all of the aquifer, and the chemical has spread through. Mr. Karson explained that there would be an extraction area toward which contaminated water is heading. He said that although a small amount of clean water might be pulled up, the water would not be recontaminated. He noted that this concern is taken into consideration when the modeling is conducted. Mr. Karson stated that the intent is to "surgically remove" the contamination and not adversely affect the aquifer, which in turn could affect pond and stream levels. He also stated that determining where to reinject or discharge the clean, treated water is just as important as extracting and removing contamination because it is imperative to maintain the balance in the aquifer. Ms. Canosa asked how raising up the water and redistributing it somewhere else is better than allowing the plume to flow to the rivers or to the ocean. Mr. Witzmann replied that once the contaminated water is removed, it is cleaned, and the clean water is then discharged.

A member of the audience asked if the CS-4 system is currently capturing the CS-4 plume or if that plume is still flowing. Mr. Witzmann replied the extraction system installed in 1994 continues to operate, but it is not functioning as hoped in that some contamination is travelling underneath the extraction wells and possibly between individual extraction wells. The audience member then asked if there will be discussion tonight about how that will be addressed. Mr. Witzmann replied that a couple of months ago AFCEE released a Proposed Plan for redesigning the CS-4 system. He reported that the proposal includes drilling three extraction wells deeper in the aquifer along the axis of the plume, and increasing the pumping rate to ensure that all of the contamination in that plume is captured.

The audience member then referred to the FS-28 alternatives and asked if it is correct that treated water would be discharged into the Coonamessett Pond or the Coonamessett River, rather than into the aquifer. Mr. Witzmann replied that this is correct and added that another option would be a combination of discharging into the pond and the river. The audience member asked what effect discharging the treated water would have on the river or the pond. He also asked if Mr. Witzmann is convinced that the treated water is completely clean. Mr. Witzmann replied that there would not be any contamination in the treated water; however, there could be significant ecological impacts associated with reinjecting the treated water into the pond or the river. He explained that this is a situation where a natural stream will become a controlled system, and whenever such an adjustment is made to the environment, the consequences are not always known. The audience member asked why not then reinject the water into the aquifer rather than emptying it into the surface water. Mr. Witzmann replied that if the water were reinjected into the aquifer it would have to be reinjected downgradient of the extraction wells. He referred to the map and pointed to the area where there would need to be a line of extraction wells, and a line of reinjection wells a little further down. He said that the water table would be drawn down at the location of the extraction wells and there would be mounding at the location of the reinjection wells, in such close proximity to the extraction wells. Mr. Witzmann added that during periods like this summer, where there is already very low flow in the Coonamessett River, the river would be drawn down so much that there would not be any flow.

Mr. Karson reaffirmed that the intent of tonight’s meeting is to present the different alternatives that are under evaluation and not to make proposals. He stated that the Air Force’s preferred alternative will be announced in January 2000, at which time the public comment period process will begin.

Mr. Harry Foster asked if there is any evidence of upwelling occurring from the FS-29 plume. Mr. Witzmann replied that at this time upwelling is not occurring. He added that as the water that makes up the FS-29 plume moves farther downgradient, it would eventually reach discharge points. He explained that there are three parts in the lifecycle of a plume: when the spill occurs; the long period when the plume is moving horizontally and slowly diving down as rainwater falls on top of it; and when the plume upwells, should it make it that far. He stated that the FS-29 plume is well in the middle section of that cycle.

Mr. Foster commented that to him the diagram appears to indicate that there is mixing between the FS-29 and CS-21 plumes, and asked if this is the case. Mr. Witzmann replied that the plumes intersect, so physically there are wells that have been drilled in this area that have contaminants that look like CS-21 and also look like FS-29. Mr. Foster asked if there are any chemical reactions taking place. Mr. Witzmann replied that there are not.

Ms. Wyatt asked if the use of an emergency generator during a long-term power failure has been considered as part of the plan. Mr. Witzmann replied that there is a period of time when the system, if down, can be restarted without losing any contamination. He mentioned that when the CS-4 system was constructed, it included an emergency backup generator, which was never used. Since that time, there have been a number of lightning strikes that have raised the issue of power outages, and the use of an emergency generator has been reconsidered. Ms. Lauren Foster added that AFCEE is considering an uninterrupted power supply system. It is taking measures to prevent lightning strikes from affecting the plant. Mr. Gadd explained that uninterrupted power supply is a voltage regulator, which would suppress the spikes created by lightning strike, thereby saving the electronics. He also noted that the plants can be started remotely.

Mr. Minior stated that the RPMs are considering what, if anything, needs to be done. He noted that at the time of design, a decision was made that the provision of emergency power was not required, even with an intermittent breakdown of power for a period of several days. Because of the recent lightning strikes, however, that decision is being revisited, and any new information will be provided to the community.

Mr. Murphy thanked Mr. Karson for holding this public meeting. He then commented that he considers Jacobs Engineering and some of ongoing efforts to be part of the solution, and not part of the problem. He stated that it is obvious that there is a problem, and he feels that it is like a poker game in that a hand of cards has been dealt, and how to play the hand is to know how to play poker. Mr. Murphy encouraged everyone in attendance to stay informed, and suggested that people sign up on the site mailing list because to be informed is the only way to be part of the solution. He also suggested that people call the Falmouth Selectmen and voice their support for the Air Force to fund town water connections to this neighborhood, including the entire "triangle area." He recommended that people also call the state representatives who are advocates for bringing solutions to this problem.

Mr. Murphy then remarked that the suggestion that residents would assume some of the cost for town water connections is "ludicrous." He stated that in his home, when his child spills a glass of milk at the table, the child cleans it up. He said that he did not spill the milk, but the milk has been spilled and he has no intention of spending his own money to have town water brought to his house so that the health and safety and psychological well-being of his family is not compromised.

Mr. Witzmann noted that there is a sign-in sheet for the site mailing list downstairs. Mr. Field also noted that Falmouth Selectman, Ms. Virginia Valiela, a Falmouth Selectmen, is present tonight.

Mr. Kaheler asked Mr. Witzmann to identify the disadvantage of keeping the present cleanup system of FS-28 as it is. Mr. Witzmann replied that the idea behind considering the additional systems is to expedite the restoration of the aquifer.

Agenda Item #8. Adjourn

Mr. Field adjourned the meeting at 8:01 PM.