CS-10 Posterboard Session and Public Meeting
The Parish of Christ the King
Route 151
Mashpee, MA 02649
July 29, 1997
3:30 - 9:00 P.M.

Agenda Item #1. Welcome and Introductions:

Mr. McGlennon introduced himself and explained that he would be facilitating the meeting. He then welcomed everyone to the meeting. He explained the three fundamental purposes of the meeting: 1) an opportunity for the public to hear about the remedial alternatives being considered for treating the Chemical Spill-10 (CS-10) plume, 2) an opportunity for the public to give their thoughts on preferred alternatives and 3) an opportunity for the public to ask questions and get some answers. He explained that the remediation program at the base is handled by the Remedial Project Managers (RPMs) and introduced them to the audience - Mr. Leonard Pinaud from the Massachusetts Department of Environmental Protection (MA DEP), Mr. Paul Marchessault from the U.S. Environmental Protection Agency (US EPA), and Mr. Jim Snyder, the general manager of the remediation program at the base. At this time, Mr. McGlennon also introduced Mr. Spence Smith, Project Manager for the CS-10 plume, to the audience and said that Mr. Smith would be giving a presentation later in the meeting.

Mr. McGlennon then asked all the speakers who would be addressing the audience to reduce the use of acronyms as much as possible and to spell them out when necessary. He then said he would give the audience five acronyms to remember. They were - 1) IRP - The Installation Restoration Program which is directed by Jim Snyder. He explained that the IRP is the fundamental, overall management team for investigating appropriate cleanup methods for the base, 2) AFCEE - The Air Force Center for Environmental Excellence. Mr. McGlennon explained that AFCEE is part of the Department of Defense (DOD) and that it is through AFCEE that funds come to the IRP, 3) US EPA - The United States Environmental Protection Agency - one federal regional office under which the federal Superfund program is administered. He stated that the base cleanup is a part of that Superfund program, 4) MassDEP - Massachusetts Department of Environmental Protection, partners with the EPA in monitoring and assisting with the guidance of the cleanup of Superfund sites in Massachusetts, and 5) RPMs - Remedial Project Managers, being the three gentlemen Mr. McGlennon had introduced earlier.

Mr. McGlennon referred to the handouts. He said everyone should have an agenda. Also, he had additional handouts for everyone, one being the CS-10 Decision Criteria Process (see attached) which provides a timeline for what happens next and when. Mr. McGlennon explained that this was not a formal public hearing, but a public meeting for the public to learn about the alternatives and for the RPMs to learn about the public’s preferences and concerns. He said that if anyone wanted to submit written comments or questions to the IRP there was a sheet explaining that procedure (see attached). He also said there was a blank comment sheet which could be filled out (see attached) and left at the end of the meeting. He said there was a site mailing list revision sheet (see attached) in case anyone wanted to add their name to the mailing list or change any incorrect addresses. Mr. McGlennon also said there was a Presentation Evaluation Form for the CS-10 Alternatives (see attached) which would be very helpful to the IRP as this was the first public meeting that they’ve had on plume alternatives and there are going to be more. He said they would like to know how they can serve the public better - by organizing the agenda differently or addressing different issues, etc. - they would like to hear from the public and take their comments into consideration when planning the next meeting. He also reminded the audience that in order to get their comments on the record they needed to be submitted in writing.

Agenda Item #2. Review Agenda & Groundrules

Mr. McGlennon said that Mr. Marchessault of the US EPA would speak first, followed by Mr. Pinaud of the MA DEP, followed by a presentation by Mr. Snyder on the background of the CS-10 plume and treatment technology. Then, Mr. Smith would walk them through the CS-10 alternatives. He said they hoped to get through by about 7:20 P.M. when they would take and answer questions from the audience and that the meeting would have to conclude at 9:00 P.M. in order to completely vacate the building by 10:00 P.M.

Mr. McGlennon then addressed the groundrules. He asked that, if at all possible, the audience would hold their questions until the end of the presentations because of the likelihood that those questions may be answered at a later point in the presentations. He recommended writing down questions on a piece of paper so that the questions are not forgotten before the Question & Answer period. He asked that the audience members who do ask questions identify themselves before doing so and that they address their questions to either Mr. Pinaud, Mr. Marchessault or Mr. Snyder. He also asked that each person ask only one question at a time so that everyone has a chance to ask a question. Mr. McGlennon reminded the audience that their questions should pertain to the CS-10 plume. If anyone should have other questions regarding other things going on at the base or other plume activity, Mr. Pinaud, Mr. Marchessault and Mr. Snyder would be available later for one-on-one questions. He said that a roving microphone and two stand up microphones were available and that it would be helpful if questions were spoken into the microphone for record keeping purposes. He asked if there were any questions about the process. There were none.

Agenda Item #3. US EPA Remarks - Paul Marchessault, Remedial Project Manager:

Mr. Marchessault stated that he had been on the Massachusetts Military Reservation (MMR) as a project manager since it was listed on the national priorities list as a Superfund site back in 1989. He said that they were there tonight to discuss the CS-10 Decision Criteria and Matrix. He said that the EPA and MassDEP have been very closely involved with AFCEE on the development of the various alternatives. He stated that the alternatives have been carried through for consideration and the supporting analyses were contained in the Decision Criteria Matrix. He also said that the alternatives had been presented to the Joint Process Action Team (JPAT) for their review and approval and that the comments and recommendations from that group had been incorporated into the matrix. He said there would be a JPAT meeting tomorrow night (7/30/97) where that group would be selecting a preferred alternative. Mr. Marchessault stated that the purpose of this meeting would be to get the public input on the various alternatives and that the EPA would provide information, if necessary, on the advantages and disadvantages of the various alternatives presented. He said that the goal of the matrix was to select an alternative that is technically sound and satisfies the threshold criteria that would develop in the decision making. He said that since the EPA has had much review and input into the matrix that the matrix is a reflection of the opinions of the EPA. He then thanked the audience.

Agenda Item #4. MassDEP Remarks - Len Pinaud, Remedial Project Manager:

Mr. Pinaud stated that this meeting would be an important part of the decision process for the CS-10 plume and that the MassDEP was there to listen to what the public feels is the right alternative for them, and to factor that information into a recommendation to the Air Force. He said that the goal was to determine an effective alternative that maximizes plume capture and cleanup while balancing the impact on human health and the environment. He said that MassDEP would be evaluating each alternative using the benchmark set by Massachusetts Secretary for Environmental Affairs Trudy Coxe and that was that the recommended alternative must be both technically and environmentally sound and publicly acceptable. Mr. Pinaud stated the MassDEP looked forward to this joint decision-making process with the public, the EPA, other state and federal agencies and the Air Force. He also said that the MassDEP was committed to an alternative which will restore and protect the sole source aquifer and the precious natural resources of the Upper Cape. He then thanked the audience.

Agenda Item #5. AFCEE Presentation - Jim Snyder, Remediation Program Manager:

Groundwater Plumes

Mr. Snyder said that he would first do a walkthrough of the CS-10 groundwater itself so that Mr. Smith’s presentation on the alternatives would be more understandable to the audience. With visual aid, Mr. Snyder pointed out that our lens, in the blue area, called the Sagamore Lens, was one of seven on the Cape and the largest by far. He said the contour lines represented the change in elevations beginning at sea level and going up to the top of the mound at elevations of above 50 feet of the groundwater table. He said this was the normal expression of how the groundwater is shaped in the Sagamore lens.

Mr. Snyder said that what had happened at MMR and other Superfund sites was that as part of the groundwater recharge process - the contaminants get in as part of the process. Snow and rainfall percolate through dry areas as seen in the green area of the map, the brown area is where the water table sits. He said that contamination is generated when it gets in the pathway of the percolation, water flowing through the soil and getting into the groundwater. So, if gasoline or solvent had been spilled or if there had been a landfill in the area, the snow and rainfall leaking through would help the contaminants to migrate into the water table, then the water table flows with gravity and additional push from percolation on the way down. At this stage, the contaminants will travel down and at this point, especially on the Cape, there will be some interaction with some surface water bodies.

Mr. Snyder then pointed out the CS-10 plume. He said it had originated at the BOMARC missile facility, which had been closed for some time - the solvents used in maintenance at that facility had ended up in the ground and the groundwater. He also pointed out Ashumet Pond, John’s Pond, Mashpee-Wakeby Pond, Snake Pond, and Buzzards Bay. He then showed a slide of a cross-section of CS-10, a cut-away of the Earth’s surface, and talked about the different contours within the plume which were represented by different colors. He said the widest areas (which were drawn by computer mapping using the data from all of the monitoring wells) represent the five parts per billion (ppb) contour lines. He said that with the contaminants they were dealing with, primarily tetrachloroethylene (PCE) and trichloroethylene (TCE) - five ppb was the safe drinking water level - the acceptable standard. Within that, there were higher concentrations. He pointed out an area believed to be above 100 ppb based on their data and a small gold area believed to be at concentrations of about 1000 ppb. Mr. Snyder then showed the cross section which showed the surface of Ashumet Pond at 40 feet above sea level and he also indicated the level of the water table. He said there werer about 140 feet in ground surface and that was at 55 feet to the top of the plume at that point. It goes across until the plume is approaching 100 feet below ground surface in a certain area and it’s some distance below the groundwater table - the plume throughout most of the region is roughly 40 to 50 feet, in some parts, 60 feet below the top of the water table.

Mr. Snyder said that one of their findings after reviewing the CS-10 data was the fact that a lot of the contaminated groundwater is in silt, or areas of fine soil, not the coarse sand usually seen at the surface on most parts of the Cape. He then showed a "cartoon" diagram, which he explained was not CS-10 or any particular plume, just a picture of what happened - the start of a source which hit the water table and started to migrate into the water, going with the water flow. As it continues to migrate, it gets to the silts and when the contaminants reach the silts, the water flows not as rapidly, however the sandy soils have water flows of one to two feet per day depending on where they are on that slope of the Sagamore lens. When the contaminants get to the silts, they are basically immobile. He said that what the cartoon is illustrating is that the contaminants in the silts will simply stay there while contaminants in the sandy soil will continue to migrate down creating a situation like the one with the CS-10 plume.

Treatment Technologies

Mr. Snyder spoke about the technologies being considered for remediation. He said that there are Extraction/Treatment/Reinjection (ETR) wells, or "pump and treat" systems, which pump water out of the ground at one location of the contaminated area, run it through a treatment plant, and then put clean water back in the ground. He pointed out the inner dashed line on the diagram which he explained represented a line of wells, each one of those extraction wells would reach out a certain distance to pump water. He said that he wanted to be sure that it was understood that these were multi-well systems, that the dashed line represents a line of wells. He said that with an extraction well, the water is screened. He said that these are areas where the water is pulled in by a submersible pump. The water is pumped to the ground surface, there is a manhole cover underneath which provides access to the controller to the pump, and he then pointed out the pipeline which goes to a building. The primary treatment they are proposing to use for the ETR system is granular activated carbon which is a carbon filter with large carbon vessels or tanks that the contaminated water would be run through with clean water coming out the other end. He said there would be all the appropriate monitoring locations testing how the carbon is doing and the quality of the effluent, the water coming out of the treatment plant as well as the water going in. Mr. Snyder said that the status of the carbon would also be monitored during the operation. The next step in ETR is that the clean water is then taken elsewhere to be reinjected into the water table - this helps them, to some degree, to help control hydraulic movement and help them to balance water drawdown. He said that one of the key problems with ETR is the potential effect on the water table. He said that a depression in the water table can be caused by the water being pulled into a well, if this is near to a surface water body, it could cause a negative ecological effect due to the change of surface water level and the natural flow of things. He said they would try to maintain that balance, that hydraulic control, by where the clean water is reinjected.

Mr. Snyder then spoke about the recirculating wells. He said that the main advantage is that they don’t create the water drawdown problem associated with ETR. In the case of the recirculating wells, you are dealing with water at the same point on the map. The water is taken out at the very bottom of the contaminated zone, cleaned in the well and then the cleaner water is dropped back into the top of that zone. He said that the purple arrows on the diagram depict the zone that is being created around the recirculating well and that the volatile organic compounds (VOCs) are removed by air stripping when the contaminated water is at the well’s surface. He said that the air stream is then taken off to a treatment plant to undergo carbon treatment to remove the VOCs.

CS-10 Timeline/Submitting Comments:

Mr. Snyder said that CS-10 was the first plume to be going through the Decision Criteria process. He stated that this was a public meeting and encouraged the audience members to fill out the comment forms and to take advantage of this opportunity to ask questions in order to increase public understanding. He also stressed the importance of public feedback so that the alternatives which are considered favorable or unfavorable could be considered in the decision making process. He said that the public comment period closes on August 8, 1997 and that the RPMs will then have until August 22, 1997 to consider the input from the public and try to make a decision that is both technically sound and acceptable to the community. He said that what will follow the decision are EPA enforceable activities, the first of which is the Draft Execution Plan which is due September 16, 1997 and which shows how the selected alternative will be implemented and the schedule for it. The EPA-enforceable date of June 28, 1999 has been established as the deadline for design, construction and start-up of the chosen alternative.

Matrix:

Mr. Snyder then said he would quickly walk the audience through the Decision Criteria Matrix, although he would not go into a lot of detail as Mr. Smith would later be explaining each of the alternatives. He said that the intent of the matrix was to compare response alternatives - a compilation of all the questions that need to be asked. He said that the matrix was developed with the regulatory agencies. He said that with a standard Superfund process, a preferred alternative would be presented at a public meeting, but in this case, they are trying to get public involvement up front before the decision point. He said it was a different approach, but that it was better to get the public input before a choice is made.

Mr. Snyder stated the categories for the criteria were Threshold criteria which addressed human health and environmental concerns and the compliance with state and federal regulations. He said the meat of the document was the Primary Balancing Criteria - the first section concerns itself with the effectiveness of the alternatives, such as percent captured by volume, percent captured by mass, all of which are based on computer modeling of the plume. The next section deals with the effectiveness of the treatment system - if there are different compounds, how effective would the alternative be at removing those contaminants. Next is the Implementability factor - how difficult would the system be to construct, how difficult is property access going to be, will there be negative ecological impacts on the surrounding area, etc. The final section under Primary Balancing Criteria is the cost - both the initial cost for construction, the operating cost and the life-cycle cost. The final category of the Decision Matrix Criteria is the Acceptance Criteria which is the section that takes into consideration the input from the public both in the forms of public-at-large comments and in formal written comments, as well as the input from the RPMs, the community involvement teams people, the Process Action Teams (PATs), the Selectmen representatives on the Senior Management Board (SMB), the Department of Public Health (DPH) and the Agency for Toxic Substances and Disease Registry (ATSDR), the Natural Resource Trustees Council (which is still in the formative stage), the regulatory agencies and the Department of Defense.

Mr. Snyder reminded the audience of the various ways that they could participate in the public comment period - written comment forms, the website, E-Mail, mail and fax. Mr. Snyder then turned the presentation over to Mr. Smith.

Agenda Item #6. AFCEE, CS-10 Alternatives - Spence Smith, CS-10 Project Officer:

Mr. Smith said that Mr. Snyder had mentioned the hydrogeology of the systems and that he would be referring to some of those points, primarily the silts and what is being done with the alternatives to hydraulicly balance the approach. These are key concepts to think about. He said that he intends to present the goals in terms of the technical aspects - the alternatives’ development, some key characteristics of the alternatives and then most importantly, present the alternatives and look at some of the pros and cons.

Mr. Smith stated that the primary goal is maximum capture and minimized impacts of sensitive environments. He said they also have to consider technical and logistical constraints - can it be constructed, what other impacts might there be. He also said that when they are talking about sensitive environments, the primary concern is the hydraulic impact, but constructability is an issue as well - what type of impact might there be in areas of sensitive habitats, etc. The other important goal of the program is to incorporate decision making that involves all the interested parties.

Mr. Smith then showed a "cartoon" slide depicting what is gone through to develop an alternative for the CS-10 plume and the other plumes currently being evaluated. He said they come up with an alternative by way of a brainstorming session, then go through a reasonableness screening, and many of the alternatives go no further. Once they find an alternative that they want to continue with, they apply some of the 3-D and 2-D analytical tools - those are groundwater models which are basically an approximation of nature - they collect a good deal of data and do their best to approximate nature through the numerical model in three dimensions, then do some runs and then evaluate to see if the model calibrates. They’ve developed a good calibration for the regional model, but that doesn’t end there. A regional model would involve the whole Upper Cape - the Sagamore Lens. Once that model is developed and calibrated it is used to then establish the boundary conditions for the CS-10 plume zoom model, which is the model that helps them to develop the alternatives. Mr. Smith said that the whole process of analytical numerical tools eventually brings them to the alternatives.

He said there are a number of alternatives that have been "parked" off to the side and haven’t been carried further because of some fatal flaw. The fact sheets (see attached) show alternatives A through G. The Decision Criteria Matrix also contains two alternatives that had been parked previously. Because of the involvement and input of the Joint Process Action Team (JPAT), Technical Review and Evaluation Team (TRET) and RPMs, parked alternatives C1 and F are also in the package - he said that these are aggressive alternatives which may be useful in getting a handle on the plume before it migrates into the silt, where it is very difficult to extract and so they may still prove to be useful.

Regarding the overall series of alternatives, Mr. Smith said they all have fairly high pumping rates in order to achieve capture - 7.2 million gallons per day for alternative A, 6.9 million for alternative B, 7.5 million, 8.5 million, and 9.1 million for the others. He said they had try to achieve the most passive pumping as possible and still achieve capture - but they are still very large volumes of water.

He also pointed out some distinctions between the alternatives. He said that alternative A involves fences along the perimeter of the plume, alternative B eliminates the northwest extraction fence, for alternatives B, C, and C1 there is a Sandwich Road extraction fence. Those three alternatives feature the Sandwich Road extraction fence rather than the Ashumet Pond extraction fence because of the difficulties of getting into that area from an access standpoint and a construction standpoint due to the potential impacts on a sensitive habitat environment. The Sandwich Road fence is near the base boundary and is something that can be constructed very readily. Alternative E is natural attenuation - this does not involve any extraction fences. Alternative F involves pumping at all the extraction fences with the exception of the northwest fence and the Ashumet Pond and has a Sandwich Road extraction fence - that includes Horseshoe Bend pumping recirculating wells. What is unique to alternative F is that extraction would be in a zone of high concentration, just upgradient from Sandwich Road.

Alternative A:

Mr. Smith pointed out the area of high concentration that he had mentioned. He said that zone contains over 1000 ppb. He also pointed out Sandwich Road along the boundary of that area and Ashumet Pond. He pointed out zones of 100 ppb and a zone of between 5 and 100 ppb. He pointed out the northwest fence, the southwestern fence, and the southern fence. He said that the blue fences on the diagram are the reinjection fences. He pointed out the west reinjection fence, referred to as the main reinjection fence. He also pointed out another small reinjection fence as well. The fences may seem to be in curious positions but they are positioned that way to balance the hydraulics. The location also facilitates the development of the capture zone. The key feature of alternative A is the Ashumet Pond fence with the other perimeter fences.

Alternative A meets the hydrologic threshold, the drawdown of the pond is within the criteria that the TRET has established. This includes flux of treated water to the pond - there are limitations as to how much water can approach the ponds and this alternative is within that limit. An important element of alternative A is that there are some rare species in sensitive habitats in that zone between Sandwich Road and Ashumet Pond. This is something that would have to be managed with construction. Access is difficult. There are a number of private properties where access would need to be acquired. Socio-economic impacts from construction and operation are the greatest with this alternative.

Alternative B:

Mr. Smith said that alternative B had the same general layout as alternative A with the exception of the fence along Sandwich Road. He said this was referred to as the uncaptured area. Hydrologic thresholds are met. This alternative has the easiest property access as it is all within MMR. The environmental impacts from construction are lowest. The twenty year life-cycle costs are the lowest with alternative B. The plume is not captured south of Sandwich Road - the estimated plume capture is the lowest among the alternatives. The socio-economic impacts from construction are the lowest.

Alternative C:

Mr. Smith said that this alternative features the same fences with the northwest extraction fence, but in order to address the uncaptured portion, it includes recirculating wells. The intent is to knock the mass down of that uncaptured portion. These are systems that wouldn’t require piping - they stand alone. It would be a matter of obtaining access for a small area of about a twenty foot radius. Most of the system would be below ground. This would provide additional capture and so, improved statistics. The twenty year life-cycle costs are higher than most alternatives and the hydrologic thresholds are exceeded for vernal pools and treated water flux to Ashumet Pond is also an issue. This may be something that can be addressed.

Alternative C1:

Mr. Smith pointed out an elongated northwest fence and the same fences along the bottom, the fence along Sandwich Road and the recirculating wells. He said it was very similar to alternative C but that it had the elongated fence to get at the higher concentration material mass before it migrates to the silt. He said there is quite a bit of silt in that region of the CS-10 plume and that migration element is an issue over time. The estimated plume capture is therefore greater. The lowest contaminant mass is caught in silt, however the twenty year life-cycle costs are higher than most alternatives. It is a much more aggressive approach with higher pumping rates. The hydrologic thresholds are exceeded - the same issue as the wells in the Horseshoe Bend area.

Alternative D:

Mr. Smith stated that alternative D is an all recirculating well strategy. He pointed out what he called the same sort of fence locations, a fence along Sandwich Road and individual units along the Horseshoe Bend area. He said that the diagram doesn’t show reinjection well fences because extraction and reinjection occur at the same locations within the well fences. Mr. Smith said that recirculating wells are an innovative technology that they are now pilot testing. He said they had just completed the pilot test on CS-10 and one is being tested at Ashumet Valley as well. The estimated plume capture is lowest among the action alternatives and there is greater uncertainty relative to the effectiveness of the system. He said that the pilot tests are done to evaluate the effectiveness and to look at what the important criteria are that need to be evaluated in order to design fully optimized systems. So, when it is said that there are greater uncertainties, that is relative to the ETR approach. The hydrologic thresholds are exceeded in this case as well.

Alternative E:

Mr. Smith stated that this is the natural attenuation alternative - it doesn’t involve any extraction or treatment. It would have the least impact to health and the environment from a construction and operation perspective. The costs are significantly less. There is less exposure path reduction than the action alternatives since the plume would not actually be removed and treated. An important element of natural attenuation is the continued monitoring of the system. It’s not a case of walking away from it, but monitoring it over to the years to track the migration of the plume. The uncaptured portion of the plume in some of the other alternatives is also something that they would be monitoring and is a natural attenuation element of those alternatives. There are greater socio-economic and water supply impacts from the uncaptured portion of the plume and does not comply with regulatory standards established for plume containment.

Alternative F:

Mr. Smith said that alternative F is the most aggressive because of the elongated fence to control migration to the silt, the perimeter fences, the Sandwich Road fence, Horseshoe Bend fences and the three extraction wells within the zone of highest concentration. Plume capture is the highest. The wells north of Sandwich Road expedite capture of highly contaminated groundwater. It has the lowest contaminant mass to go to the silt. Capital and twenty year costs are the highest among the alternatives. The hydrologic thresholds are exceeded with vernal pool drawdown and treated water to the pond.

Alternative G:

Mr. Smith stated that alternative G is the no action alternative. He said that it doesn’t involve institutional controls, but it would cause the least impact - right up there with natural attenuation - to human health and the environment from a construction and operation standpoint. The costs are the lowest, but there is no active exposure path reduction. There would be greater impact from the uncaptured portion of the plume because it would not be removed.

In summary, Mr. Smith pointed out the pumping rates and that alternative F has the highest rate. He also said that those statistics are available within the Decision Criteria Matrix. He said that there are not pumping rates for the recirculating wells, only for the ETR wells. He also referred to the part of the Matrix which addresses volume and mass per capture and he said that this is the key information to focus on, particularly mass. He pointed out the key numbers for the active systems - what is actually removed and what goes to the silt. He said that C1 and F are both very aggressive approaches where the mass that goes to the silt is reduced significantly.

He also said that when these alternatives are modeled, a 100-year time frame is used. He said that the mass removal at 20 years and 50 years doesn’t increase a great deal for each of the alternatives. There is a plateau effect at 20 to 50 years. There is a hardly perceptible change from 50 years to 100. So, the operational lifetime is within that neighborhood (of 20 years) - this makes the assumption that everything is moving in physical transport in the aquifer to the systems. He then pointed out a plotted curve illustrating the 10 and 20 year marks and the various alternatives and the area where the curves really flattened out in terms of percent mass removal. He said that the systems should be thought of in terms of 20 to 30 years.

Mr. Smith then showed a slide to give an idea what the costs of the alternatives would be - alternative A at $41.8 million in total capital costs at today’s dollars, alternative B - $39.8 million, $44.3. $45.8, and so on - generally in the neighborhood of $39 to $47 million. The operation and maintenance costs for the active systems would be in the general neighborhood of $3.5 to $4 million. The natural attenuation and no action alternatives would be less - there would be no capital costs, but there would be a five-year review. There would be monitoring systems to be developed with the attenuation alternative E and monitoring to be done throughout its operation.

Agenda Item #7. Question & Answer Session:

Mr. McGlennon opened up the question and answer session by reminding the audience of the groundrules. He also stated that Ms. Amy Brand of CH2M HILL was present with a laptop computer to write down the comments of anyone who wanted to have their comments recorded for the record. He also said that highly technical questions would be turned over to Mr. Smith.

Q: Bob Robichaud of John’s Pond North Cove Association: How does a concentration of 1000 ppb become contained in a small area like the one in CS-10? Is it going to move or expand? What will happen to it between now and 1999 when the cleanup begins?

A: Mr. Snyder: It will continue to move and will probably have some continued dispersion as it travels down its path - it won’t stay at those high levels forever. Remember that it probably started far north.

Q: Mr. Robichaud: How would the concentration get so high in that location?

A: Mr. Snyder: From a series of releases of the contaminant throughout the history of the plume.

Q: Mr. Robichaud: But the original location of the spill was a long way from that point.

A: Mr. Snyder: Yes, it started in high concentrations, and has traveled in high concentrations.

Q: Mr. Robichaud: Is it only alternative F that actually treats that locality?

A: Mr. Snyder: That alternative goes after it aggressively. It will continue to travel and the Sandwich Road fence will see that (high concentration area) also in a matter of a few years.

Q: Mr. Robichaud: It seems that you are going to use extraction wells in the locality where it is now.

Alternative F is the only alternative where you are actually working in that area.

A: Mr. Snyder: Yes.

Q: Bob Fitzpatrick of West Falmouth: Is well water taken out of the silt area for treatment?

A: Mr. Snyder: Typically, silt does not produce enough water for a well to pump for treatment.

Q: Mr. Fitzpatrick: If the contaminant is in the silt, is it not then a problem?

A: Mr. Snyder: We consider it basically "held". As the cartoon drawing showed, the sandy soil part is slipping away from the silt contamination. That silt will continue to release very low levels slowly over the years.

Q: Mr. Fitzpatrick: Regarding the socio-economic aspects, it would seem dependent on whether the treatment plants were designed as block buildings or as attractive buildings. Has there been any thought to that?

A: Mr. Snyder: We look at that as part of the qualitative assessment of the socio-economic impact from construction. But the immediate concerns are with the period of heavy construction of the wells, pipelines and treatment plants.

Comment: Chris Neill of Falmouth representing the Cape Cod Sierra Club: We will be submitting some comments in writing, but in summary for now, this is our approach for recommending a plume containment plan - you have to minimize the disruption to the neighborhoods - people have suffered enough. A lot of the plans do take that into consideration and that is important. Stick to already disturbed or vacant lots. Minimize road construction in the neighborhoods. Contractors should have strict instructions, deadlines, with strict penalties to keep them towing the line. You should be dealing with contractors who are finishing jobs by the time they are supposed to be finishing them. How to choose the best cleanup with the minimum damage? We, (the Sierra Club) like alternative F because of the aggressive treatment of the hot spots. The sooner the mass is reduced the better. We want to see recirculating wells near sensitive areas as in alternative F - there would be recirculating wells around Ashumet Pond. Also, there should be aggressive treatment of the leading edge of the plume - as in this alternative. Another very important area, which hasn’t received a lot of attention, is that of monitoring and assessing. These are only model projections - we need to know how these plants are performing over time. There need to be some strict guidelines - perhaps a two year re-evaluation with public comment to tell us how the chosen alternative is actually working. The data to generate that evaluation has to come from multiple wells and multiple samplings of those wells. Lastly, an adaptable management plan has to be built in very strongly in the event that the alternative doesn’t work out as expected. Again, we are in favor of alternative F, to treat it aggressively with recirculating wells around the sensitive areas - we are willing to live with a little environmental alteration in order to achieve an aggressive cleanup.

Comment: Paul Marchessault: Regarding the comment that Mr. Neill made about monitoring - the Air Force is required to submit a performance monitoring evaluation - on paper it can be predicted where everything is going to go - they have to show us all the wells they are going to monitor, frequency, and once the system is operational, they will make adjustments to be sure that the system is working as designed. (The public would be involved in the decision-making process if there are any redesigns or mid-course corrections.)

Q: James Olman of Falmouth: According to the map of the plume - it looks like the plume goes well beyond the area that was talked about tonight - down below Route 151 and further into Falmouth. Is that contamination in sandy soil and what will happen to that over time?

A: Jim Snyder: That is the Ashumet Valley plume which is now going through a similar process and there will be a meeting about that over the next couple of weeks.

Q: Roy Woodward of Horseshoe Bend Way: It seems that Horseshoe Bend is going to bear the brunt of the off-base recirculating wells. How much weight has been given to the residents of Horseshoe Bend Way toward the final approval vs. the Mashpee Selectmen, the Falmouth Selectmen, and the Sierra Club. They all mean well, but we are the ones who are going to have this stuff in our backyards. Does our input have more weight, less weight, equal weight on the approval criteria?

A: Mr. Snyder: We are taking comments from the public at large but we are also trying to separate out comments from affected neighborhoods. This is a very isolated neighborhood being affected by this plume and this alternative.

Q: Joe Dellagala of Horseshoe Bend Way: There are now approximately six properties for sale on Horseshoe Bend Way. If you start digging up the street with necessary construction over the next two years - what happens to the people who are suffering and trying to sell their homes and can’t do so? Furthermore, hasn’t any thought been given to the impact this will have on the wildlife - because there is going to be a high pitch noise - what will happen to the wildlife when they hear this? But most importantly, what about the people who live here - if we’re going to take the crux of this, we want to know more. I’ve heard nothing so far on how you’re going to treat these people being affected.

A: Mr. Snyder: The construction at Horseshoe Bend would create difficulties for the neighborhood. There is probably more of that with the Ashumet Valley plume. We are looking at trying to avoid or minimize these problems. When we go in to get access to properties it will be through a lease or easement payment associated with that for the homeowners. There will be an annoyance with the construction project for a period of a few months. Another part of the evaluation is that we look into what ecological habitats are there and we don’t do any construction specifically that will endanger or threaten them - that is part of our assessment - right along the pond, heavy construction would do environmental damage - we identify that, take a look at a very aggressive approach to dealing with the plume knowing that there will be a tradeoff - we are trying to weigh all of that and minimize it.

Q: Dick Taylor of Hatchville: Are you going to contact everyone in the Horsheshoe Bend area, stop by their houses, see what they think about it and try to talk them into it?

A: Mr. Snyder: We have made sure to contact everyone and get all the information out to them. We hand delivered a lot of flyers to the affected neighborhoods and set up neighborhood sessions to go out and talk. We hope to talk to as many people as we can.

Q: Mr. Taylor: As far as the high pitched squeal - there was a lower noise. . .

A: Mr. Snyder: The unit you are talking about has some high pitched noises, the recirculating wells have some high volume, some lower - we are looking at in vault construction, below ground - the noise should be very well managed. There are two or three wells going across the rotary in the clearing right across from Horseshoe Bend, those have been insulated somewhat and they don’t generate a lot of noise.

Comment from unidentified gentleman: The six houses for sale on Horseshoe Bend sound like an opportunity - six houses you could buy and put pumps on them.

Q: John Farrington of Falmouth, member of the Science Advisory Panel of Barnstable County: Regarding your capital costs and the impacts that you’ve looked at in terms of construction - do they include de-commission - in other words going back once the process is completed in twenty or fifty years.

A: Mr. Snyder: No they don’t, these are initial capital costs and annual costs - they do not include de-commission.

Q: Mr. Farrington: Because then you’re going to go through a whole disruption cycle again and that is going to mean something to the people in the neighborhoods who are going to have to go through this exercise of having people come in and take out (the equipment). I would respectfully suggest that you include these costs and the effect there may be on wildlife at that particular time. When the pumping is stopped , I assume there is no adverse effect on the ecology of the vernal pools and other surface waters.

A: Mr. Smith: I don’t anticipate an adverse affect because we are being very careful about meeting the design criteria in the modeling effort. The next step beyond that - we have an ecological monitoring program that is ongoing and over the next two or three years we are collecting a good deal of ecological data, actually looking at the organisms and evaluating what the critical parameters are to observe as we operate the systems. From a hydraulic standpoint, once we go to a non-operating mode, the systems are designed to localize the effects, to minimize them.

Q: John Ford of North Falmouth: Regarding the recirculating wells, it says in the literature that has been handed out to us that there are 80 recirculating wells located in the U.S. Could any of the agencies provide us with a list of those 80 sites to determine the effectiveness of those wells?

A: Mr. Marchessault: I could do some research in the office and see if we have a list and can get that to you.

Q: Mr. Ford: Have you evaluated from the historical experience of these other recirculating wells that have been put in - does it give you confidence that these wells will be effective in this case?

A: Mr. Snyder: We considered some other previous uses and have pilot tested locations. There is still some uncertainty about (the tests) but that is part of the process.

Q: David Dow of East Falmouth: Regarding operation and maintenance costs and maintaining the system over a 20 or 30 year period - as time goes on you will have to replace pipes, pumps, etc. - so it seems that the operation and maintenance costs could actually go up as you get further into the project. Also, how disruptive will it be to replace pipes that leak or pumps that aren’t working properly. How often are you going to monitor the system to be sure it’s working as specified.

A: Mr. Snyder: There will be established a performance monitoring network to assess the right location and depth, aerial location of wells - to monitor how well they’re performing against what we design them to do - that’s part of the process. There will be data output from sampling events and analysis of the performance - what trends are developing - are contaminants dropping, etc. Regarding the question about cost - we chose a very simple approach based on a 20 year life cycle - it’s going to be a low estimate. Regarding what it would be like to replace a pump or repair a pipeline - it’s like looking at a public works’ project basically - to repair a pipeline there would be minimal excavation. Pumps are very easy as they are very isolated, working in a vault, should be fairly quick, no excavators or anything like that.

Q: Richard Koehler of East Falmouth: Aside from the hydrologic criteria, there’s some kind of criteria about extraction of water and surface body that’s treated - it’s my understanding that treatment is only supposed to make the water better - am I misunderstanding or are there some concerns about the quality of the treated water?

A: Mr. Snyder: There is concern that the treatment process may start affecting dissolved oxygen or ph of the water or total organic carbon - the good things that are in the water. If you start disrupting those you have a high percentage of that disrupted treated water going into a surface water body that’s not used to that kind of water - we’re concerned with those ecological impacts. But we’ve had a lot of input from experts on how much the adjacent surface water bodies could handle treated water based on changes from those types of parameters such as dissolved oxygen and ph. There have been threshold percentages established that we try to stay within with our models. They want us to minimize the pond flux to no more than 25% treated water.

A: Mr. Smith: The thresholds that we violated were the design criteria thresholds. As Mr. Snyder mentioned, we do modify the water through treatment. The absolute values of what’s appropriate in that modification - what can be exceeded in terms of ph - are being determined. But these aren’t insurmountable problems, they are things that can be addressed in the treatment scheme such that the treated water is appropriate.

Q: Mr. Dellagala: Getting back to the noise level - you say it’s going to emit a noise - I don’t know how high pitched the noise is, but will it affect the hearing of children in the neighborhood later on?

A: Mr. Snyder: We have been collecting noise data around the pilot plants that are operating. That will be part of the design and it will be addressed.

Q: Mr. Dellagala: I wouldn’t want to see children in that area have their hearing affected when they’re older. Also, will there be five of these units put in? Will they all be emitting this noise for twenty years?

Would you think that if these five units are emitting this noise that anyone would buy (property) in that area? Do you think the property will devaluate horribly? There’s not enough concern given to the impact on the people in my neighborhood. I would like to see a meeting with the people in Horseshoe Bend Way so they can express their concerns. I appreciate the fact that you’ll clean it up - that doesn’t bother me at all. I’m sure you’ll do fine with the engineering. I’m interested in what happens to the people that live in the area - before and after.

A: Mr. Snyder: That’s almost all private property - there’s very little public right-of-way in there that’s usable. So, any access would have to come from the good graces of allowing a lease or easement from the property owners.

Q: Mr. Dellagala: But you could always get in by eminent domain if you had to.

A: Mr. Snyder: Not on private property.

Comment: Mr. Pinaud: After taking a look at some of the recirculating well systems last week, I agree. One of those systems was making an unacceptable noise. But, I believe that we can engineer around that problem. Also, if we have to go door-to-door in that area, then we should do that. We should do that very very soon to meet with folks. (Maybe a meeting could be hosted for the people.)

Comment: Mr. Woodward: Unfortunately a lot of the people on Horseshoe Bend are only there on weekends or on vacations in the summer. They may not have even received all the literature that’s been sent out. I agree with Mr. Pinaud that you should get together with each and every one of them, even if it needs to be on a Saturday or Sunday.

Q: Sue Walker of Sandwich: Comparing page one to page three in the alternative evaluation matrix, under threshold criteria number 1, B environment - it says impact on threatened endangered species habitat. Under alternative A there’s a question mark. Under alternative C1 and F, there are filled in circles. Then on the back under roman numeral five, H - impacts associated with operations to environment - now alternative A has a filled in circle and C1 and F are opened. After hearing Mr. Smith tonight, I understand that C1 and F have to do with vernal pool drawdown and the treated water in the pond. It’s difficult for the public to compare the question mark with full circles and empty circles. I’m trying to figure out which makes the most ecological damage.

A: Mr. Snyder: Regarding the question mark under the impact to threatened endangered species - that is after the heavy construction along the pond’s shoreline - once it’s installed and operational, the operations don’t create any more hazard or damage to the ecological receptors.

Q: Ms. Walker: Do you know how many vernal pools are affected?

A: Mr. Smith: There’s one vernal pool that is the critical vernal pool and there was another one which had been mapped but has since been removed from the list. The one that remains is about 1000 feet from Ashumet Pond. I don’t have the maps with me but that can be identified.

Q: Ms. Walker: Do you have them outside?

A: Mr. Smith: I don’t.

Q: Ms. Walker: Does anybody else have any comments on judging the ecological impact - from what Mr. Snyder said the construction would be short term and things would go back to normal.

A: Mr. Snyder: Right.

Q: Ms. Walker: For C1 and F, with the recirculating wells, that would be a three to five year impact?

A: Mr. Snyder: Yes.

Q: Mr. Farrington: Although this may be a controversial issue, in the alternatives that were "put in the parking lot", was there one that addressed treatment of the plume’s impact to surface waters? With a no-alternative type of approach can you consider the confines of the interim record of decision (IROD) if water is in the pond either by private or public wells - can the federal government pay for treatment at the well site when it’s withdrawn from surface water?

A: Mr. Snyder: Yes, we can do that. We can look for replacement wells. We are in the process this year of taking compensation to make the water main construction and environment of the neighborhoods as well as parts of Hatchville - in other words, we’re making private well residents part of the public water supply.

Q: Mr. Farrington: If the concern is primarily with the public health, then that can be met by treating at the well site as you withdraw the drinking water.

A: Mr. Snyder: All the alternatives say that there’s some uncaptured portion. As the plume is migrating we would continue to take people off private wells, put in public water or deal with affected public wells.

Q: Mr. Farrington: Shouldn’t that be explicitly stated in the document?

A: Mr. Snyder: The document does talk about the replacement of water supply.

Q: Mr. Taylor: Which alternative do you (on the panel) prefer?

A: Mr. Marchessault: From a remediation standpoint, we are not ready to present what our preferred alternative is. We have found advantages and disadvantages with each one. We are here to hear from the public and see what kind of input we get on what they consider to be the good and bad points of the various alternatives. At this point, we really can’t say what our preferred alternative is.

A: Mr. Pinaud: I would like to echo the EPA’s comments . . . and I don’t think Mr. Snyder’s going to tell us what he thinks.

A: Mr. Snyder: We all have the same task, all three of us - we’re looking for technical soundness and part of the process is to hear from the public before making a decision.

Q: Unidentified gentleman: I’m not familiar with the IROD business either. As I understand it, the only formal criteria have to do with the amount of these materials in the drinking water. The mass removal calculation doesn’t really show what the picture would be if you just cleaned the water up to that level and stopped. If you’re talking about 99% mass removal, that could mean that 99.99% of the water is drinkable, depending on dilution of facts. I would like to have seen a map of the minimal treatment it would take to get at most of that area if you’re not going to take the approach that suggests treatment at the wellheads. Is there some over-treatment here is the question I’m asking.

A: Mr. Snyder: Some of the parked alternatives had a lot more in-plume pumping. We do a lot of modeling discussion with the technical experts in the program - those other alternatives were a little more aggressive, their fatal flaw being that too much water was being moved, so they were parked. But this plume does speak to a large area of extent.

Q: Mr. Dow: Since part of the CS-10 plume is going under Ashumet Pond and between John’s Pond and Ashumet Pond - can you tell us when the field studies will be completed and at what point you will decide whether that non-contained portion of the CS-10 plume needs to be dealt with as an action item?

A: Mr. Snyder: That investigation is going on right now and we’re due for field work to be completed with September time-frame models. That field effort will probably require a few more wells as most investigations do. Anything that we find requires another action is going to be dealt with similar to this process that you’re seeing tonight. We are now seeing that concentrations have dropped quite a bit formulating underneath Ashumet Pond. With that area of high concentration north of Ashumet Pond, we consider any alternative to work in that area regardless what you find beneath and beyond Ashumet Pond.

Q: Do you have a high level of confidence from the computer models that the CS-10 plume is not going to affect Ashumet Pond?

A: Mr. Snyder: We are fairly confident that with the way the alternatives are laid out that it will not have any effects. Hydraulic modeling and computer modeling is fairly close, particularly with drawdown. That’s a real concern we’re looking at with the pond - you don’t want to draw groundwater next to a pond causing a reverse flow. I believe we can control all that and get it right . . .

A: Mr. Smith: We have some results coming in now from monitoring points that are being installed in the pond. The plume is at a depth where we’re not seeing it in the pond but up ahead - in the neighborhood of forty feet - that we are seeing it any concentrations - but they’re very low. This is right along the margins of the pond so it’s not very deep at that point, probably within about 100 feet of the shoreline.

Q: Mr. Dellagala: Would that change if you went into a deeper portion of the pond?

A: Mr. Smith: What we’re doing with this study is monitoring along the edge where there’s a good deal of the recharge to the pond, the groundwater that’s moving into the pond at that point. These are flow-through ponds so in that area of Fisherman’s Cove, it’s flowing in and the groundwater is flowing out the other end. The question is what amount of the plume, if it is flowing towards the pond . . . but from our initial conceptual modeling it looks like, and this is being borne out with some of our field work now, it’s primarily recharged by the clean water that’s over top of the plume. So, we’re still evaluating what might be moving vertically toward the pond, if any, from that contaminated portion. That question of greater depths toward the center of the pond will be part of that evaluation.

Q: How much serious consideration has been given to actually purchasing lots in neighborhoods that would be affected? If you’re spending 25 million dollars on capital construction costs to set up the whole thing, buying even a number of lots would seem a small total cost or are there other considerations . . .

A: Mr. Snyder: Even if we buy the property, we need to do the construction. It still comes down to the issue of what the other neighbors want - there may still be one person who wouldn’t be happy about selling lots. That all needs to be determined.

Q: Regarding the issue of noise - it would seem a sound-proof door could be engineered.

A: Mr. Snyder: I agree. We should be able to control the noise. Another neighborhood had a similar issue with one of the pilot tests - they were concerned about the noise.

Adjournment:

Mr. McGlennon asked if there were any other questions or comments. There were none. He thanked the Remedial Project Managers and Mr. Smith for being "almost brief enough to stay within his time limit", and said that they will be availabe at the conclusion of the meeting. He reminded the audience that Ms. Brand was available to take down their formal written comments. If they wanted to send in a written comment later, he reminded everyone that they would need to be in by August 8th. He also said that there were others from the IRP staff present as well as Mary Sanderson, Virginia Valiela from Falmouth, Ellie Grillo from the DEP, etc. and to feel free to go back and see these individuals "to bend their ear". He reminded everyone that they would need to leave by nine o’clock.

The meeting adjourned at 9:00 P.M.