Responsiveness Data

Name/Organization of Comment Originator			Comment	Response
1	Ray Bowman	Mashpee Environmental Coalition	The collective opinion of the Coalition's Board is: "Alternatives C1 and F are the best of the options listed." The following comments are provided as an overview to the Board's discussion and are not necessarily consistent with established dogma.	Preference noted.
2	Ray Bowman	Mashpee Environmental Coalition	1) MCLs are meaningless where a plume has multiple contaminants. No accurate human health risk can be computed and treatment to "below Detectable Levels" is desired.	Risk assessments are appropriate for determining human health and ecological risk associated with multiple contaminants. The goal of treatment to the plume is to treat to background and below detetion levels prior to reinjection.
3	Ray Bowman	Mashpee Environmental Coalition	2) Recirculating well technology does not appear to provide as high a removal efficiency as ETR. If EDB or phosphorus becomes a consideration RWT appears to be unacceptable.	In general this is correct. Recirculating well technology would require technical modification such as above ground liquid phase treatment to remove EDB or phosphorus.
4	Ray Bowman	Mashpee Environmental Coalition	3) Alternative A requires extraction wells in an area too close to the pond and residences plus a high silt capture and therefore has low desirability.	Assessment is correct. It is an alternative to maximize capture but with potential construction, hydrological and ecological impacts.
5	Ray Bowman	Mashpee Environmental Coalition	4) Alternative B leaves a large area unremediated.	Alternative B leaves less than 2% of the mass of the plume unremediated.
6	Ray Bowman	Mashpee Environmental Coalition	5) Alternative C has a low system capture when compared to C1 and F.	Correct.
7	Ray Bowman	Mashpee Environmental Coalition	6) Alternative D uses RWT and is unacceptable, (see 2).	Preference noted.
8	Ray Bowman	Mashpee Environmental Coalition	7) Alternatives E & G are unacceptable and require no comment.	Preference noted.
9	Judith G. Stetson	General Public	My knowledge of CS-10 and its possible clean up alternatives is very limited, but I strongly oppose natural attenuation without monitoring, the last "treatment technology" described in your Public Notice ad. This is the option we have been living (and dying) with for 50 years and it is NOT ACCEPTABLE! Natural attenuation with monitoring is only marginally better. What is known about the biochemical effects of partially attenuated chemicals on the plant and animal life of soils, sediments, marshes, estuaries and harbors over time? As I understand it, recirculating wells are still being tested. Unless this treatment technology proves to restore a greater quantity of groundwater to a greater degree of purity than the ETR technology, I would favor "pump and treat". Mr. Karson said that the used charcoal from ETR goes off-Cape for cleaning. Is this process environmentally sound? Please make sure that any solutions to our local problems do not degrade anyone else's environment.	Thank you for your opinion, it has been noted. The chemicals of CS-10 are not in any of those surface habitats and are not expected to be. It appears that recirculation wells do not provide the same level of quantity or purity but may still have application in areas where pump and treat technology is not feasible. The process of carbon regeneration is environmentaly sound. The process is managed by specialized firms and is regulated.
10	Paul Zanis	General Public	My comments are as follows; no reinjection should take place. Pump to Vineyard Sound or manmade ponds.	Reinjection is the recommended hydrologic approach which minimizes disruption to regional water flow. Pumping to Vineyard Sound is precluded by regulation and scientific practicality. Pumping to man made ponds would generate unacceptable disturbances to surface water conditions and the regional groundwater flow.
11	Jane Coojan	General Public	1) With the alternative plans presented what are the specific details of affect for residential neighborhoods?	Alternatives A, C, C1, D, and F would have construction-related impacts on the Horseshoe Bend neighborhood. This would involve drilling of extraction or recirculating wells and performance monitoring wells near Horseshoe Bend Way. If Alternative A is selected, then approximately 10 extraction wells would be installed. In addition, piping installation, similar to water line construction, connecting the wells with a treatment plant on base would be necessary. A four to six foot diameter manhole cover would be visible following restoration activities at each extraction location. Recirculating wells would not require piping to a central plant but would have similar vaults for the wells and an equipment/treatment unit which may be located above ground in a shed or below ground in an additional vault at each location.
12	Jane Coojan	General Public	2) What test results, to date, have you regarding the two pilot recirculating wells? And, how do these results compare to effective use in Europe?	The AFCEE recently completed pilot tests of two recirculating well technologies in the CS-10 plume and in the Ashumet Valley plume. The results of the pilot tests are contained in a draft report currently under review by the EPA and DEP. The pilot test results indicate that the systems are effective in removing contaminant mass for the aquifer conditions present within the CS-10 plume; however, the development of the recirculation cell appears to be fairly sensitive to geologic variability. Consequently, detailed designs of remedial systems involving these technologies will likely require additional detailed geologic data in the areas in which they are sited. In addition, they may require additional monitoring during initial operations, relative to more common extraction, treatment, and reinjection (ETR) approaches, to demonstrate compliance with performance goals. Currently, the recirculating well systems are limited to treatment of contaminants that may be "air stripped" from groundwater ETR approaches involve removal of groundwater from the aquifer, pumping to a treatment plant, fluid-phase treatment, and distribution to reinjection wells. Fluid-phase removal may enable greater treatment flexibility if contaminants that are not readily strippable are encountered.
13	Jane Coojan	General Public	3) Is the CS-10 plume migration as currently documented headed in the direction(s) of any operating or targeted public well sites? And do you have maps of the location of residential well sites in the area of or direction of the known plumes migration guestimates?	Current data indicate that the primary amount of the mass associated with the CS-10 plume is north of Ashumet Pond. Our investigations between Ashumet and Johns Ponds and to the south, currently underway, have detected what may be the leading edge of the CS-10 Plume. Monitoring well clusters, having ND (non-detect) results, indicate that the plume is deep within the aquifer and does not extend south of Southport Village or Rte 151. Private wells are known to exist in the area south and east of Johns Pond. If a potential threat to them is identified, measures will be taken to provide a municipal water connection. At this time, no existing Mashpee public supply wells are impacted. Proposed well sites may have a zone of contribution that passes through known plume areas in the upper reaches of the Massachusetts Military Reservation. These will be evaluated as part of the overall remediation alternatives.
14	Jane Coojan	Gereral Public	4) Should we, the public, presume that the highest plume capture, alternative Plan A, is or is not the highest priority of AFCEE?	No. Alternative A has notable implementation issues. AFCEE is looking for the most balanced approach, which is technically and economically feasible.
15	Jane Coojan	Gereral Public	5) Would you rank, via AFCEE priorities, plume capture, vs. potential effects on ecological habitats and versus socioeconomic impacts for me?	Plume capture is the overlying goal of the CS-10 approaches. However, they can not present unacceptable or unmanageable ecological or socio-economic impacts. The approaches must also be technically and economically feasible.
16	Jane Coojan	General Public	6) If adequate financial recompense is awarded to property owners in areas deemed to be adversely impacted by plume cleanup operations should there be a delay in installation of or start up of systems?	No delays are expected at this time. Delays, however, could occur for several reasons. For example, weather conditions could delay the construction schedule. Labor strikes or acts of God could occur. In spite of an offer of fair compensation allowable under federal law, some property owners may still choose not to participate in the cleanup, which may cause delays.
17	William O. Burwell, A.I.A.	General Public	I am interested in finding out at this particular time, if there is a symbiotic solution for the problem of access, the potential for using the infrastructure of your remediation system (or any part of it) as a future asset to the community, and the possible PR value of offering something to those most affected - in exchange for the anxiety and inconvenience they may have felt.	While your thoughts on the potential beneficial use of the infrastructure of the treatment systems being considered for MMR are extremely interesting, an in-depth consideration of these benefits is beyond the scope of this process at this time. Thank you for the background information on equipment and possible manufacturers.
18	Eugene Courier	Neighborhood	I am voting for Alternative B. I am concerned with impact to Ashumet Pond and neighborhood integrity.	Your preference has been noted.
19	Anonymous	General Public	This letter is in response to the request for public comments regarding the cleanup of the CS-10 plume. As a general comment, I have attended some of the public meetings and have heard statements from the JPAT, EPA, DEP, and others concerning a "change in focus" for the cleanup, and that the cleanup is now more important than ever thought before. However, this seems to be the choice of a small, yet vocal, minority. I agree that the focus has changed, but there are no risks with the plume if it is left to run its course (if my interpretation of the Plume Criteria information is correct). Additionally, there are other plumes out there that are not going to be cleaned up (abandoned dry cleaners, old gas stations, town landfills). Therefore, if the focus has changed, then perhaps now is the time to perform a risk evaluation, instead of rushing in with an expensive cleanup operation that will ultimately benefit no one, except the giant government bureaucracy that is trying to protect itself, at the cost of hundreds of millions of taxpayer's dollars. Following are my questions: 1) Why will a cleanup be performed when the CS-10 plume presents no risks?	Monitored Natural Attenuation and No Action are the alternatives under consideration that address lower risk. The risks presented assume no residential use of plume water, however, using MCLs there will continue to be degradation of previously uncontaminated aquifer.
20	Anonymous	General Public	2) Why will Otis plumes be cleaned up when other plumes in the western Cape Cod area will not be cleaned up?	The MMR site has been designated as a Federal Superfund site and is therefore subject to the standards established under the Federal CERCLA law. The other non-CERCLA sites in Massachusetts are being addressed for remediation in accordance with State law known as the Massachusetts Contingency Plan (MCP), 310 CMR 40.000. The MCP requires a potentially responsible party to make clean-up decisions to a level of "no significant risk". This risk determination addresses risk to human health, welfare, and the environment. The same MCP rules apply when the State agrees to clean-up a site with public money. Similar cleanup requirements exist in MCP and CERCLA. Other plumes on western Cape Cod are in different stages of the cleanup process.
21	Anonymous	General Public	3) What is the benefit (to the water supply and ecosystem) of cleaning up the Otis plumes when other plumes will not be cleaned up?	A benefit, in some cases, is protection of uncontaminated aquifer.
22	Anonymous	General Public	4) My understanding is that not all of the CS-10 plume will be cleaned up (a portion of it goes into "silt" or "escapes"). What is the benefit (to the water supply and the ecosystem) of cleaning up only a portion of the CS-10 plume while leaving some of it in the underground aquifer?	A portion of the contaminant mass contained in the plume reaches and is impeded by silt. The average groundwater velocity typical of the sandy deposits of the Mashpee Pitted Plain deposits within CS-10 are 1 foot a day while that of the silts generally are less than 0.1 foot a day. Consequently, it is not economically or technically feasible to remove contaminant mass from the silts through the use of a pump and treat approach. Removal efficiency of wells within the silts is very low. However, in addition to slowing contaminant movement, the silts often present anaerobic conditions which are ideal for bacteria that biodegrade chlorinated compounds.
23	Anonymous	General Public	5) My understanding is that there is an "Augat" plume south of Otis that contains the same types of contaminants as the CS-10 plume. Why are the EPA and MassDEP allowing the "Augat" plume to naturally disperse, but requiring the cleanup of CS-10? This seems to be an arbitrary application of the rules.	Remedy consistency is a very important aspect of the clean up process. The contamination that has been detected from the Augat facility is being studied under the States 21E program, EPA does not have any involvement on the investigations being performed or the proposed remedial actions to be conducted. The Augat site is located on Route 28 in Mashpee and is under investigation by the potentially responsible party (PRP). The plume extends approximately 7,500 feet from the Augat site to Shoestring Bay and contains primarily TCE and PCE up to 800 ppb. The PRP has completed Phase II Investigations under the MCP which the MassDEP is currently reviewing. The MassDEP has asked the PRP to do additional work to determine where the plume is entering Shoestring Bay, at what concentrations, and to perform a detailed human and ecological risk assessment for the site. The company is submitting a Scope of Work by the end of August, 1997 for the additional work. The Mashpee Public Library is serving as a public repository for all reports relative to the Augat site investigations. A decision has not been made to allow the plume to naturally dispurse.
24	Anonymous	General Public	6) There are also other plumes in the area that may or may not contain the exact same chemicals as the CS-10 plume. Some of them (that I am aware of) are old town landfills, the Jay Braden Thompson plume, and old gas stations. Even though the chemicals may not be the same, the government has led us to believe that the chemicals are harmful to humans and the ecosystem. So, if this is true, then why clean up only CS-10? If the other chemicals are harmful, what is the benefit of only cleaning up CS-10 and not the Thompson plume, for example?	Other plumes on the Cape are being cleaned up. The MMR work is at a different stage than other Cape plumes.
25	Anonymous	General Public	7) Before the Otis problems were "discovered" , we were led to believe that septic tanks and cesspools (almost every home and business has one) are the biggest threat to our water supply on the Cape. What is the benefit (to the water supply and ecosystem) of cleaning up CS-10 when there are septic tanks and cesspools still discharging to the underground aquifer?	The contaminants of concern from CS-10 are probable carcinogens not usually associated with domestic sewage. Malfunctioning septic systems and cesspools are still a threat to the Cape's water resources especially for the reason mentioned; almost every home and business in the area has one. The MassDEP strictly regulates discharges from wastewater treatment plants and recently revised 310 CMR 15.000, known as the Title V Regulations, to improve the minimum design standards required to treat residential wastewater on-site. In addition, Title V targets nitrogen-sensitive areas for added protection around public water supplies.
26	Anonymous	General Public	8) What are the impacts to ponds and the ocean (shellfishing beds, for example) from the CS-10 plume versus septic tanks and cesspools?	The impacts are expected to be non-existent (i.e. non-detectable levels of CS-10 contaminants in ponds or ocean). Impacts from septic tanks and cesspools deplete oxygen and can resilt in fish kills. Increased algae growth deminishes aesthetic quality of ponds.
27	Anonymous	General Public	9) How often do you predict that fishing in the ponds or ocean (regular fishing and shellfishing) will be restricted due to the CS-10 plume (if it is not cleaned up) versus contamination from cesspools? How often do you predict that ocean fishing will be restricted due to "red tide" (or another natural occurrence) versus the CS-10 plume (if the plume is not cleaned up)?	Never expect fishing to be restricted due to the CS-10 plume. No prediction available on fishing restrictions from other causes.
28	Anonymous	General Public	10) If the millions of dollars are spent on the CS-10 plume cleanup, will we be able to drill a well south of Otis and drink the water (within the 50 to 100 years)?	If the containment is effective water supply wells can be placed south of Otis. A goal of the program is to return effected groundwater to potential use as drinking water. Since all of the groundwater in this area is designated as a sole source aquifer, it adds more importance to restoration as a goal. Pristine water is the first choice for drinking water for all communities in the Commonwealth. The MassDEP strictly regulates drinking water supplies to ensure that clean water remains available. For example, there are some situations where a water supply inadvertently becomes contaminated and treatment must be provided at a wellhead to protect the public. Alternative sources of clean water are sought before the treatment option is considered. The cleanup of CS-10 and other MMR plumes is intended to stop the spread of contamination and treat contaminants so that future generations will have clean water sources available to them. Wellhead treatment is allowable by both agencies. However, it is not a preferred approach.
29	Anonymous	General Public	11) Will a public water supply well be allowed to be drilled anywhere south of Otis if the CS-10 plume is cleaned up?	If cleaned yes. If held in place, probably not.
30	Anonymous	General Public	12) My guess is that no matter what type of cleanup is performed, a supply well drilled south of the base will require some form of treatment. Why won't EPA and MassDEP allow well head treatment, instead of plume cleanup (at the cost of millions of tax payer's dollars) AND well head treatment?	A goal of the program is to return effected groundwater to potential use as drinking water. Since all of the groundwater in this area is designated as a sole source aquifer, it adds more importance to restoration as a goal. Pristine water is the first choice for drinking water for all communities in the Commonwealth. The MassDEP strictly regulates drinking water supplies to ensure that clean water remains available. For example, there are some situations where a water supply inadvertently becomes contaminated and treatment must be provided at a wellhead to protect the public. Alternative sources of clean water are sought before the treatment option is considered. The cleanup of CS-10 and other MMR plumes is intended to stop the spread of contamination and treat contaminants so that future generations will have clean water sources available to them. Wellhead treatment is allowable by both agencies. However, it is not a preferred approach.
31	Anonymous	General Public	13) Why does the water supply for the Town of Barnstable use wellhead treatment, but wellhead treatment does not appear to be an alternative for the CS-10 plume?	The Town of Barnstable has four private water companies which draw water from many water supply wells. Only one water company in Barnstable is using wellhead treatment. Wellhead treatment is being used for the company's Maher wells. The Maher wellfield has a large user demand and, unfortunately, became contaminated with volatile organic compounds from several sources. These plumes came from several commercial sources in the Hyannis area. The MassDEP investigates these sites as part of it's Barnstable Aquifer Protection Project, (BAPP). The water company held a District meeting with its customers and determined that wellhead treatment would be an acceptable way to deal with the contaminated wells as no other alternatives were readily available. When a water supply becomes contaminated it is addressed on a case-by-case basis by the supplier. MassDEP strictly protects public water supplies by law to avoid contamination by harmful chemicals. Prevention is the key element of the laws and regulations. (See also answers to questions #30, #35 and #47 for DEP's position on wellhead treatment.)
32	Anonymous	General Public	14) Is the Town of Barnstable allowed to use wellhead treatment (and not cleanup the landfill plume) because it is a municipality and the rules for a municipality are different?	No, the rules are not different for a municipality, such as Barnstable, regarding the applicability of wellhead treatment. Please refer to the response to question #31 for more information on why Barnstable has wellhead treatment for one wellfield. Contamination, which seems to come from the landfill, has not impacted any public water supply wells. The potentially responsible party will have to assess and clean up the plume. In the meantime, DEP's Solid Waste Division has requested that additional wells be installed for monitoring purposes between the plume and Princess Cove and ahead of the wellfields to the south of the landfill. MassDEP regulations require that unlined landfills be closed in order to protect water supplies. Barnstable is now placing waste in a lined landfill.
33	Anonymous	General Public	15) Why won't the EPA and MassDEP clearly state to the public all of the available options for the plume? For instance, well head treatment with no cleanup would be cheaper and the benefits to the public would be the same. All we hear about is an expensive cleanup, but we don't hear about any of the less expensive options that would result with the same benefits.	The remedial alternatives that were evaluated examine various cleanup options. Well head treatment might be an option a town water district would pursue with otherwise limited options.
34	Anonymous	General Public	16) If well head treatment is used instead of cleaning up all of Otis, would fewer government jobs (directly related to the Otis Project) be available?	Yes. Treatment plants will require manning for decades as will wellhead treatment systems. However, treatment plants would typically require more personnel.
35	Anonymous	General Public	17) What is the benefit of a CS-10 cleanup when the water supply will contain some hazardous chemicals, no matter what is done, and the water supply will have treated anyway (no matter what is done)?	Pristine water is the first choice for drinking water for all communities in the Commonwealth. The MassDEP strictly regulates drinking water supplies to ensure that clean water remains available. There are some situations where, for example, a water supply inadvertently becomes contaminated and treatment must be provided at a wellhead in order to protect the public. Alternative sources of clean water are sought before the treatment option is considered. The cleanup of CS-10 and other MMR plumes is intended to stop the spread of contamination and treat contaminants so that future generations will have clean water sources available to them.
36	Anonymous	General Public	18) What is the benefit of spending millions of dollars on the CS-10 cleanup versus spending a fraction of that amount on developing an alternate water supply?	Alternative water supplies are developed in response to a threat to an existing system (private or public supply well) to ensure future capacity or mitigate a contaminated system resulting from a plume emanating from MMR. The decision to spend dollars on cleanup is based on the need to protect human health and the environment (ecological). Alternative water supply development does not eliminate the need for cleanup.
37	Anonymous	General Public	19) What is the difference in impacts to property values with the CS-10 system installed and running (choose any of the systems shown on the fact sheets) versus just letting the plume take its natural course? (Please note that I am not asking about the impacts due to one system or another, I am specifically asking about any system versus no system).	As plumes migrate, or portions there of, they will continue to underrun more property off-base. The only restriction to property owners may be on the use of groundwater, but this concern is resolved with connection to public water at Air Force expense. While the plume underrunning property may be a detraction, it presents no risk and public water is an improvement to property.
38	Anonymous	General Public	20) What is the benefit of spending millions of dollars on the CS-10 cleanup versus spending a fraction of that amount on another program, like education or a healthy-start program for school children?	We appreciate your concern for other public programs and agree they are important. However, there is a mandate under several federal and state laws to identify and address contaminants to protect public health, welfare, and the environment. This will provide greater security for future generations as well.
39	Ed Weber	General Public	I favor Alternative A because I feel it is technically the best way to capture the plume.	Preference noted.
40	Deborah McDonald	General Public	I prefer Alternative A because I feel it will do the most capturing the plume without disturbing the long-term aesthetics of the neighborhood.	Preference noted.
41	Richard Koehler	General Public	The pump buildings need to be soundproof. Reduce the machinery noise, especially whatever makes that high-pitched noise, e.g., a bad bearing.	Extraction and reinjection wells associated with pump and treat systems are virtually silent, having electric submersible pumps located deep within the wells. The blowers associated with the recirculating wells that were recently pilot tested within the CS-10 plume, however, are a source of noise. These systems will be designed to minimize noise through a variety of methods including use of quieter components, sound insulation, vibration dampening, destructive interference of sound waves, and locating equipment in below ground vaults.
42	Roy Woodward	General Public	I like Alternative A because it appears that is the best way to capture most of the pollution. I also would like my voice, as a resident of Horseshoe Bend Way, to count more than people who aren't affected by any of the plans.	Your preference for Alternative A is noted. The Air Force, EPA, and MassDEP consider the preferences of the affected neighborhood separately from other members of the public. This is demonstrated by the fact that there is a separate line item in the matrix for the affected neighborhood as an acceptance group. However, all opinions must be considered equally when making a final decision.
43	Dave Nowlan	General Public	Based on the information provided I'd like to submit my preference for option "F" as demonstrated last evening. This is the most aggressive option and has the best clean up potential.	Preference noted.
44	Billy "Buff" Buffman	General Public	Here are my questions for the CS-10 plume: 1) Why are you going to spend so many millions of dollars on the CS-10 plume cleanup when there is no risks if the plume is left the way it is?	A goal of the program is to return effected groundwater to potential use as drinking water. Risk is part of the criteria, and there are Monitored Natural Attenuation and No Action alternatives, which are proposed minimal actions.
45	Billy "Buff" Buffman	General Public	2) How many government jobs will there be if the plume is cleaned up as planned? How many government jobs will there be if well head treatment is used instead of the cleanup wells and cleanup plant?	No firm estimates are available but assume that treatment plants will require more planning than wellhead treatments.
46	Billy "Buff" Buffman	General Public	3) Why isn't the JBThompson plume being cleaned up? Is it because the state is responsible and the rules are different: Aren't the pollutants the same as in CS-10?	The State has fully committed to cleaning up the J. Braden Thompson Road site (JBT) even though the MassDEP is not the responsible party. The "rules" followed by MassDEP include assessing and cleaning up the site in accordance with the Massachusetts Contingency Plan (MCP) and all work is done within the State contracting guidelines. Some of the contaminants in the JBT plume are the same as the CS-10 plume at MMR. MassDEP is completing additional investigations needed to design the final treatment system which is expected to be developed fall 1997 and put out for bid.
47	Billy "Buff" Buffman	General Public	4) If more water is needed for this area why can't this area use well head treatment like other towns in Massachusetts? Are the rules different for this part of the state?	Pristine water is the first choice for drinking water for all communities in the Commonwealth. The MassDEP strictly regulates drinking water supplies to ensure that clean water remains available. There are some situations where, for example, a water supply inadvertently becomes contaminated and treatment must be provided at a wellhead in order to protect public health. Alternative sources of clean water are sought before the treatment option is considered. The cleanup of CS-10 and other MMR plumes is intended to stop the spread of contamination and treat contaminants so that future generations will have clean water sources available to them.
48	Billy "Buff" Buffman	General Public	5) Are people drinking contaminated water now? Will they be drinking contaminated water in the future? If the CS-10 plume is not cleaned up, but well head treatment is used, would people be drinking contaminated water?	A. No MCL exceedances known in any private of public wells. B. Potentially C. No
49	Billy "Buff" Buffman	General Public	6) You used to be able to buy TCE in the hardware store to clean out your cesspool. Have you looked at the impacts due to the home use of TCE?	The chlorinated solvent Trichloroethylene (TCE) has been in use for many years in a variety of products. It has been used for degreasing and dry cleaning and is contained in printing inks, paints, lacquers, varnishes, and adhesives (U.S. EPA data). TCE detected in the CS-10 plume is likely to be primarily associated with activities at MMR due to the location, depth and extent of the plume.
50	Billy "Buff" Buffman	General Public	8) Why are we spending huge amounts of taxpayers dollars to clean up the aquifer when there are no risks (other than the risk of fewer government jobs if its not done)?	A goal of the program is to return effected groundwater to potential use as drinking water. Risk is part of the criteria, and there are Monitored Natural Attenuation and No Action alternatives, which are proposed minimal actions.
51	Billy "Buff" Buffman	General Public	9) What good does it do to clean up one plume (CS-10 for instance) when there are other plumes that won't be cleaned up (municipal landfills, for instance)? Aren't the chemical s the same? Are the rules different depending on who is responsible for the pollution?	The chemicals in many of these sites are similar types of contaminants. There is a benefit to cleanup the CS-10 plume, since the levels that have been identified are well in excess of drinking water standards, and could have an effect on existing and proposed drinking water supplies. Many other sites on the Cape are being addressed and evaluated under the State 21E program, which seeks groundwater cleanup remedies from the responsible parties. In the case of landfill closures, the State works with the individual towns to determine the most feasible cleanup option and schedule.
52	Billy "Buff" Buffman	General Public	10) Do people realize that the taxpayers on the Cape will have to foot the bill for this cleanup? How much will our taxes go up from the cleanup you recommend? How much less would our taxes go up if well head treatment was used?	Cleanup is federally funded, as part of the Department of Defense budget and the impacts to your federal tax burden will be non-detectable. It is our federal tax dollars nonetheless.
53	Bob Fitzpatrick Robert and Winifred Fitzpatrick	General Public	We wish to vote for Alternative F. As a Falmouth residents, we feel that the extraction method/configuration that will remove the most contamination from the ground water is the plan of choice. Our second choice is alternative C1.	Preference noted.
54	William Kurker	Neighborhood	In my opinion, Alt. G is the best solution. Leave it alone and let nature clear it out. It's too much tax dollars to spend for years not knowing if it will even solve the problem the only other alternative I would appr. would be Alt. A. I do not want any noisy pumps or any buildings in or around my property.	Preference and concern noted.
55	Frank Belanger	General Public	C1 and F are acceptable because they are high in both system and total capture.	Preference noted.
56	Richard G. "Gus" Johannsen	General Public	1) General. I have been a resident of Cape Cod for three years and have closely followed the events taking place at MMR during that time. I have attended several public JPAT meetings and regularly review the available materials when I am at the Falmouth Library. I also have a technical background in biology and chemistry which allows me to understand the issues fairly well. Given this, I must say that I am appalled at the way the MMR site is being handled by the various government agencies responsible for running things. I know that most of the public citizens who speak at the meetings clamor for more action, more aggressive cleanup, more investigation, etc. I however, believe most of these people are uninformed and are motivated primarily by emotion. In my option, far too much action is being proposed and considered at MMR. The reason for this is obvious to me: the Air Force, EPA, DEP, and other responsible agencies are bowing to public and political pressure for drastic cleanup measures, when such measures are absolutely not justified, either technically or legally. To justify the kind of cleanup being considered at MMR, there must be an imminent risk to public health and/or the environment. In my opinion, the risks at MMR are minimal. Risks associated with drinking tap water are much greater than those associated with the MMR plumes, I am certain. The problem is one of public perception. The public perceives there to be a major problem at MMR, and there has been no effort to convince them otherwise. Sensational articles in the local papers containing numerous exaggerations and half-truths, and politicians currying public favor (and votes) by railing against inaction and overspending at the base don't help matters either. The perception is that there is a major public threat at MMR, and the evil government is trying to hide it and get away without doing anything. I believe this is far from the truth. The Air Force seems to be doing everything it can to move the process along, but is hindered by the aforementioned public perception and a ponderous review and approval system. To actually do something that makes technical sense at MMR seems a difficult goal, given the structure of things. My suggestion is this: we need to delay the schedule (for CS-10) and all the other plumes) for a short time while the overall approach at MMR is reconsidered. It seems a foregone conclusion that extensive, drastic measures will be implemented at all the plumes at MMR. Why? Because it's MMR. Because it's Cape Cod. Because an uninformed, emotional public applies a huge amount of pressure to do as much as possible regardless of the need. The normal rules don't seem to apply to MMR. If the kind of extensive cleanup system being considered is actually installed at CS-10, I believe it will be a case of waste, fraud, and abuse of monumental proportion. The EPA, DEP, and the Air Force will have done the American taxpayer a deplorable disservice. The facts call for limited action: cleanup of hot spots, monitoring, fate and transport modeling, and continuing he policy of keeping the public informed and putting everyone who needs it on public water.	Under CERCLA and the 1990 National Contingency Plan (NCP), EPA is directed to meet certain expectations in addressing ground water contamination. Under the NCP, EPA is expected to return usable ground waters to their beneficial uses wherever practicable within a time frame that is reasonable, given the circumstances of the site. When restoration of the ground water to beneficial uses is not practicable, EPA expects to prevent further migration of the plume, prevent exposure to contaminated ground water, and evaluate further risk reduction. The preamble to the NCP states that for Class I waters, which are ground waters of high value that are irreplaceable sources of drinking water and/or ecologically vital, preliminary remediation goals should generally be set at Maximum Contaminant Levels and non-zero Maximum Contaminant Level Goals. EPA's preference is for rapid restoration, when practicable, of Class I ground waters and contaminated ground waters that are currently, or likely in the near-term to be, the source of a drinking water supply. An imminent risk requires that an immediate action be taken. The remedial program is meant to address long-term risks. The main issue is that groundwater contamination is greater than the drinking water standards, and the program goal is to determine use and value of the groundwater and to cleanup to their designated use. Since this water is designated as a sole source aquifer, the goal is stringent unless it can be proven technically impracticable. In addition, the current existing land use is residential, which supports cleanup to residential standards. It is important to ensure that this area has safe, potable drinking water supplies. If the plumes remain unchecked over time, more people will require connection to the public water supply, and there are limited options for finding new available sources in many of the surrounding towns.
57	Richard G. "Gus" Johannsen	General Public	2) My main comment after reading the Decision Criteria Matrix and supporting text is that there appears to be no risk even if no action is taken at CS-10. The risk calculations show that there is no unacceptable risk to people or the environment for the Natural Attenuation and No Action alternatives. I fail to see the use in spending $100 million of taxpayers money over 20 years of there are no benefits - no reduction in human health or ecological risk. Besides the enormous monetary cost, significant damage to the environment is likely if construction of these alternative is undertaken. Please provide a logical , defensible explanation for why such drastic action is being contemplated for what appears to be a relatively minor problem.	The contamination at MMR is not a relatively minor problem and the "no action and Monitored Monitored Natural Attenuation" alternatives do indeed fail with respect to risk considering the matrix evaluation criteria designated under IA1 and IIIB4. These alternatives propose to allow groundwater contaminated above drinking water standards to advance downgradient of MMR into residential neighborhoods gradually depleting the remaining resources of potable water available. The USGS has compiled a model of contaminant plume expansion from the base that illustrates the loss of more of the Upper Cape aquifer in the next few decades. This Superfund site is located geographically at the top the Sagamore Lens at the groundwater divide. The plumes at MMR are defined as those areas above the Maximum Contaminant Levels (MCLs) or other risk based standards. Therefore these plumes, should be catured and treated. Without treatment future water supplies would be jepordized because the contamination would spread out affecting more, private and public water supplies and natural resources for an even greater period of time.
58	Richard G. "Gus" Johannsen	General Public	3) As stated in my second comment, doing nothing at CS-10 results in no unacceptable impacts to human health or the environment. There is, however, a hot spot of contamination just north of Sandwich Road which contains high concentrations relative to the rest of the plume. It would seem reasonable to capture this hot spot before it moves into (or under) Ashumet Pond, even though there is apparently no risks associated with letting it go. Therefore, there should be an alternative the consists of capture of the hot spot, with natural degradation and long-term monitoring of the rest of the plume. This would probably only require 5 or 10 years of pumping to accomplish, and would be relatively inexpensive. This alternative would be a reasonable compromise and would fall halfway between the No Action/Natural Attenuation alternatives and the other alternatives consisting of more extensive measures - a middle ground not currently covered by any alternative. Impacts due to construction and operations of this new alternative would also be minimal. Please add this new alternative to the matrix.	The concept was evaluated at your recommendation and did point out the significance of the Sandwich Road fence.
59	Richard G. "Gus" Johannsen	General Public	4) The risk assessment performed for the IROD assumed that someone would install a water well within the plume and use it for drinking water and other residential purposes (IROD, pages 7-1). The Decision Criteria Matrix says that the drinking water pathway does not exist since everyone within the plume is automatically put on city water by the Air Force and no one drinking the water (Sections III.B.1 and III.D). Please explain this inconsistency.	Risk assessments provide a conservative evaluation of the potential impacts that an unmitigated plume of groundwater contamination may have on human health or the environment. The evaluation tends towards the worst case which here would be the installation of a private well within the plume. The IROD established the requirement of dealing with the drinking water pathway. The decision matrix resolved the exposure concern by requiring a public water supply connection to eliminate the pathway by means of an institutional control. The alternative water supply for potentially affected residences is part of the solution package for the CS-10 plume. Without that institutional control additional project activities would have been needed to address the human health risk. The matrix is consistent with the IROD.
60	Richard G. "Gus" Johannsen	General Public	5) If it is true (and it appears to be) that nobody is, or will be, drinking contaminated water at CS-10, then the risk assessment performed for the IROD is flawed and doesn't reflect reality. Therefore, since the containment action outlined in the IROD is based on a flawed risk assessment, should it not be revisited? There appears to be no legal or technical basis for the types of actions being contemplated at CS-10. Please discuss the legitimacy of the IROD in light of these issues.	Risk assessments provide a conservative evaluation of the potential impacts that an unmitigated plume of groundwater contamination may have on human health or the environment. The evaluation tends towards the worst case which here would be the installation of a private well within the plume. The IROD established the requirement of dealing with the drinking water pathway. The decision matrix resolved the exposure concern by requiring a public water supply connection to eliminate the pathway by means of an institutional control. The alternative water supply for potentially affected residences is part of the solution package for the CS-10 plume. Without that institutional control additional project activities would have been needed to address the human health risk. The matrix is consistent with the IROD.
61	Richard G. "Gus" Johannsen	General Public	6) Section II. The only ARAR not met by the No Action or Natural Attenuation alternatives is that they do not meet the containment provision specified in the IROD. All other ARARs, including federal and state groundwater quality standards, appear to be met. Is the IROD itself an ARAR? If the IROD itself is based on incorrect assumptions, shouldn't this be taken into account? Based on the facts, these alternatives should not fail this criterion and should be considered.	The Interim Record of Decision (IROD) is not an Applicable or Relevant and Appropriate Requirement (ARAR). ARARs are contained in the IROD.
62	Richard G. "Gus" Johannsen	General Public	7) Section III.C.3 says detailed fate and transport modeling would need to be performed before the persistence of the plume could be known. Why hasn't this been done? How else will it be known what would be the result if no active measures (or limited measures) are taken? The lack of fate and transport modeling adds to the perception that the Air Force is predisposed towards choosing an extensive, drastic action at the site, probably motivated by uniformed public and political pressure. Before anything else less than a full-blown cleanup system can be considered at CS-10, this modeling needs to be performed. Please provide a logical reason for why fate and transport modeling has not been performed for CS-10, and/or discuss when it will be performed.	The commenter is correct that detailed fate and transport modeling has not been done to develop the alternatives. The primary objective of the alternatives presented is to achieve the goal of 100 % capture of the plume. To meet this objective, a conservative modeling approach has been to assume that advective or physical transport is the critical parameter to characterize plume migration. This approach allows the AFCEE to evaluate how aggressive the pumping strategies will need to be, including expected location of well fences, in order to attempt to meet the 100% capture goal. The commenter is correct that the persistence of the plume, within the limits of the capture systems, is dependent upon environmental fate of the contaminants the kinetics of contaminant interaction with the aquifer media and how they are degraded by natural chemical, physical, and biological processes. Generally, the increased clean-up time expected from processes of chemical transport retardation is expected to be offset by processes of chemical, physical and biological degradation. However, it is our expectation that we will be conducting fate and transport modeling during detailed design work and prior to construction of the capture systems to develop refinements to the adopted strategy.
63	Richard G. "Gus" Johannsen	General Public	8) The threshold criterion that precludes choosing limited action at CS-10 is Section 1.A: "Exposure pathways eliminated, reduced, or controlled?" No Action and Natural Attenuation receive an open circle, thereby failing the criterion and putting them out of contention. It appears to me that this criterion inherently assumes that there is unacceptable risk to start with; this is why action is typically taken at a site - to eliminate or reduce risks to human health or the environment. Since there are no unacceptable risks at CS-10, either now or in the future, there is no need to eliminate, reduce, or control exposure pathways. Therefore these two alternatives should not fail this criterion.	Alternatives E and G fail the threshold criteria because they do not eliminate, reduce or control the groundwater exposure pathway. The IROD (pp 7-1) takes the conservative position that "contaminated groundwater would be used for drinking water and other residential uses." There is a risk from drinking contaminated groundwater (either existing or future use). A private well would therefore present an unacceptable potential risk as a completed pathway could occur. The provision of alternative water supply as an institutional control will eliminate that exposure pathway and thus could be considered in the final alternative selection process as a partial or total solution. The criterion is correct in its initial screening of the alternative. Later in the matrix, we use institutional controls to eliminate the exposure pathways and allow further consideration of the alternative.
64	Richard Hugus	General Public	My choice for the best treatment system for the CS-10 groundwater plume is for Alternative C-1, with the following additions: 1. of recirculating wells already in place in the southern hot spot being kept in operation, not shut down as is now being proposed 2. of recirculating wells being installed in the southern end of the northern high concentration area 3. that the presently undelineated toe of the CS-10 plume -- whether in, under, or beyond Ashumet Pond -- be addressed as part of the eventual full containment of the CS-10 plume. This is in line with the majority opinion of the Plume Containment Team as of its meeting July 30, 1997.	Preference noted.
65	Rick Robbins	Neighborhood	The alternative I think would be the best choice would be alternative A. I am saying this ONLY if the wells are installed down the middle of Horseshoe Bend Way. The piping could then be run down the way as well as placed under Sandwich Road to the filtration bldg to be located a short distance from the road on (sp?) gout. Property so as not to be seen or heard by those living along Sandwich Road. By placing the system along the middle of the road it would eliminate the problem of destroying wetlands as well as not needing access to private property. If I had a second choice it would be alternative B. This also eliminates accessing private property and according to the percentage plume capture chart, does a very good job of cleanup.	Preference noted.
66	CC Group of the Sierra Club Christopher Neill	General Public	The Cape Cod Group of the Sierra Club would like to thank the Air Force Center for Environmental Excellence for the chance to comment on plume capture alternatives for cleanup of the CS- 10 Plume. The Cape Cod Group of the Sierra Club has for many years been active in calling attention to the threats of groundwater pollution emanating from the Massachusetts Military Reservation in Bourne, Sandwich, Mashpee and Falmouth. We have also for many years pressed for action to clean up the plumes of toxic solvents that have contaminated more than 66 billion gallons of drinking water, forced the closing of 400 private wells and resulted in untold stress to residents of these four communities. Although it has been a long tune in coming, we are gratified to see concrete plans for specific plumes presented for comment We also commend the efforts that have been made to keep the public informed of the decision-making process. The Club believes that the maintenance of openness and full public participation in the plume cleanup plan will be essential for the ultimate success of the selected project configuration. We offer the following general comments that outline our position on what the general approach to selecting action alternatives for specific plumes should be. We focus on two areas: 1) minimizing disruption to communities that are affected by intensive cleanup activities, and 2) doing the best cleanup job with the minimum threats to natural resources. Minimizing Disruption to Communities The prospect of having a well or treatment plant on one's property or in one's neighborhood for a period of up to 30 years is a sobering one. Citizens will do their share, providing the AFCEE does its utmost to minimize disruptive impacts in eighborhoods. The following steps should be taken to lessen impacts to residential neighborhoods: - Plans that deploy extraction wells and place treatment facilities on already public road rights-of-way should be favored over placing those facilities on private home lots. Other already disturbed lands, such as utility corridors should be selected for facilities where at all possible, even if this reduces the total amount of the plume captured by a small degree. - No reinjection wells should be located where they would be upgradient from homes that currently rely on private drinking water wells, thus potentially resulting in the use of treated water. Best Cleanup with Minimum Damage The movement of millions of gallons of groundwater per day has the potential to disrupt natural hydrological patterns especially in sensitive areas such as wetlands. The AFCEE needs to strike a balance between minimizing cleanup and minimizing natural resource damage. We suggest several guidelines for achieving this goal: If a plume has hot spots of high contamination, treat hot spots first and with the heaviest rates of pumping. Use recirculating wells and not extraction, treatment and reinjection near sensitive areas like wetlands and vernal pools where large changes in water levels would be detrimental to natural habitats. The leading edge of the plumes should be treated where at all possible to prevent contamination of as much new area as possible. Monitoring needs to be included as part of each plume containment plan. Groundwater monitoring should impacts of the pumping activities on groundwater levels and on contaminant levels. This monitoring should include sampling from multiple tests from specified wells. This is crucial to judge how well the plan is working. Sensitive area monitoring should be conducted to determine water level drawdown and efficiency of contaminant removal. This should also be done at multiple times. Flexibility needs to be worked into these plans so they can adapt over time to improve their performance and can be modified should serious problems arise. The main construction impacts should occur on the Massachusetts Military Reservation. The areas of highest contamination (hot spots) north of Ashumet Pond should be captured via axial recirculating well technology. Recirculating well technology should be used adjacent to Ashumet Pond. These wells should be located on vacant lots. This will reduce socioeconomic impacts and impacts on wetlands. Extraction, treatment and reinjection with cross gradient technology should be employed elsewhere. This includes the southwest extraction fence, southern extraction fence, Sandwich Road extraction fence and extended northwest extraction fence. This is designed to minimize movement of contaminants into silts. Minimize groundwater drawdown by extraction fences and mounding by reinjection fences by placing extraction and reinjection fences as close together as possible Favored Alternative: F Next Most Favored Alternative C1	Suggestions proposed are good ones and the program has been utilizing these strategies as they are developed.
67	CC Group of the Sierra Club Christopher Neill	General Public	- Flexibility needs to be built into the long-term pumping scheme to deal with problems such as disruptive changes to the water table, that arise from the active cleanup. In here should be public input into reassessment of each plume cleanup after not less than three years.	Comment noted. The performance monitoring evaluation plans that are to be submitted will contain flexibility to allow for changing conditions over time. Under EPA regulations, AFCEE is required to assess the performance of the system and any modifications necessary every five (5) years. However, the public will be kept well informed on the operation of each of the treatment systems to be installed, and if necessary, evaluation can be performed prior to the five (5) year period if conditions warrant.
68	CC Group of the Sierra Club Christopher Neill	General Public	There should be a scheduled public review of how well each plan is working at a pre-determined time after each plume containment plan goes on line. We suggest a maximum of two years post start-up.	Comment noted. Although there is no scheduled public review on the operation of the systems, periodic updates on the operation of the systems with respect to their design characteristics should be made available for public review.
69	William Kurker	Neighborhood	I do not want any buildings built where they can be seen. I don't want to hear any noise. I go along with Alternative G, let it alone.	Preference noted.
70	Jean Innis	Neighborhood	Alternative B seems to be the best option because recirculation wells have not been proven to be effective.	Preference noted.
71	Leroy Woodwald	Neighborhood	I would like to change my rec. from A to F providing that the recirc. wells on Horseshoe Bend are totally underground and silent, and to expedite the extraction fence and recirculating wells, if this can't happen then I will stay with A.	Preference noted.
72	Charles W. Alexander	Neighborhood	1. I'm in favor of either C-1 or F.	Preference noted.
73	Edward Weher	Neighborhood	1. The Air Force buy all of Horseshoe Bend Way at full market values (market values as a clean area). 2. The Air Force lease back for 99 yrs. to the owners and their estate. Lease back at $1.00 per year.	The Air Force can only lease at or buy property at fair market value, as needed to support construction and operations.
74	Karl Prinz	Neighborhood	A major problem that I have confronted is the extremely disturbing noise that is coming from the operation of the test pump system that is located on Sandwich Road at the beginning of Horseshoe Bend. It is intolerable. Any chosen system must solve the noise problem before installation. The increasing publicity about the plumes has adversely effected the value of my property. The Air Force should look into some means of compensating the owners of property that has been affected, especially the loss in value that has been created by the MMR.	The blowers associated with the recirculating wells that were recently pilot tested within the CS-10 plume are a source of noise. These systems will be designed to minimize noise through a variety of methods including the use of quieter components, sound insulation, vibration dampening, destructive interference of sound waves, and locating equipment in below ground vaults.
75	Karl Prinz	Neighborhood	I choose Response B for the following reasons: Property access difficulties south of Sandwich Road would be huge. I would actively oppose pumping stations and other activities in this area. Ecological areas south of Sandwich Road are very sensitive and require the greatest of care. Horseshoe Bend would suffer significant socioeconomic impact "because of the intrusive nature of the system and the need for long term maintenance of wells, pumps, and pipelines in the community". The entire system would be on MMR property under this plan.	Preference noted.
76	Senior Management Board Selectmen	Senior Management Board Selectmen	The SMB Selectmen wish to state their preferences in writing regarding the remedial alternatives for CS-10 presented and discussed at the 6 August Senior Management Board meeting. We have listed our preferences by town. Please note that SMB member Nancy Caffyn has submitted her comments and preference via the Town of Mashpee's letter dated 6 August 1997. Haydon Coggeshall of Bourne prefers C1. His comments are as follows: Preferred, with additions as suggested by the JPAT. Virginia Valiela of Falmouth prefers C1 or F. Her comments are as follows: Preferred, with additions as suggested by the JPAT. Can live with this alternative. Bob Jones of Sandwich prefers C, C1 and F but will defer to the wishes of those towns most affected by this plume.	Preference noted.
77	Conservation Commission	Town of Mashpee	Alternatives A,B,D,E, and G are not favored, due to (respectively) concerns about the efficacy of mitigation measures, portions of the plume that would remain untreated and/or insufficient removal of contaminants.	Preferences noted.
78	Conservation Commission	Town of Mashpee	We would also like to insert a cautionary note concerning the threshold of 0.5 feet for changes in ambient pond levels (0.2 feet in vernal pools). While these would seem to be reasonable under most conditions, such as changes during drought/low water episodes could be more damaging to nearshore plant and animal communities than otherwise might be. Has that possibility (and possible remedies) been considered: (Ashumet, like other area ponds is relatively high now, but for much of the last ten years it, and isolated wetlands in the vicinity, have been lower than historical mean water levels.) In general, if the possibility exists to lower these thresholds even more, such would be encouraged.	The design targets are scientifically based and have been developed in conjunction with the ecological TRET. They reflect a ecological conservative estimate of change that would minimize the potential impact associated with groundwater treatment systems. The scientific basis of the design targets are presented in the Work Plan for Ecological Assessment Associated with Groundwater Plumes and Remedial Activities at MMR (AFCEE 1997). These thresholds, such as the 0.5 feet of change in water level, was developed to assist engineers and hydrogeologists in providing ecologically sound alternatives for groundwater treatment systems. However, during the operation of these groundwater treatment systems the downgradient surface water bodies will be monitored for a variety of physical, physicochemical, and chemical parameters. As part of this monitoring plan, contingencies have been developed to respond to unacceptable changes or conditions trending toward an unacceptable ecological impact. Water level data collected in 1993 (not current conditions) has been used to calibrate the groundwater and to establish a baseline water level to which the model compares drawdown/mounding. During final design additional model refinement will be conducted in an attempt to minimize potential impacts of the selection alternative.
79	Dunn. & Kulis	AVPOI	Based on information gleaned from public meetings, poster sessions, literature, news accounts and conversations with personnel associated with the clear-up of the MMR we lend our support for CS-10 Plume Response Alternative B. There are several reasons why we favor option B. The most important reason is that this option will restrict all well installation and construction to the MMR property. Alternatives A, C, D, require well installation on private property to varying degrees This has the potential to further delay implementation of the project without significant gains in the amounts of contaminants captured. This is especially true if litigation is required to gain access to the private properties on the northwestern perimeter of Ashumet Pond. Alternatives A, C, and D also have the drawback of impacting sensitive ecological habitats adjacent to the pond. We believe that the marginal benefits of near pond remediation do not out weigh these risks.	Preferences noted.
80	Dunn. & Kulis	AVPOI	Even though we support alternative B we are disappointed that none of the alternatives for treatment of CS-10 consider treatment of the phosphorus plume which lies above the northwestern most lobe of the CS-10 plume nearest to Ashumet pond. It is our understanding from conversations with the 102nd Fighter Interceptor Wing (FIW) that remediation for the phosphorus plume will be funded by the 102nd FIW. In the interests of achieving the most cost effective and expedient solution, the final design plans for CS-10 should recognize and include this parallel effort to treat the phosphorus plume. The phosphorus plume will have the most ecologically deleterious impact on the pond of all the MMR plumes. Because of the time critical nature of the threat from the phosphorus plume, it would be prudent to determine if treatment of this plume could be accelerated by including this effort with the chosen CS- 10 alternative. This could easily be accomplished, for example, by the addition of additional extraction and injection wells for the phosphorus plume and utilization of the CS-10 treatment facility to process contaminated ground water from both plumes.	Phosphorus contamination is not associated with the CS-10 plume. Phosphorus is associated with the Ashumet Valley plume which originates in the areas of the former waste water treatment infiltration basins and the former fire training area (FTA-1), each of which are closed. FTA-1 is undergoing remediation. Options for remediation of the waste water treatment basins are currently under evaluation. The hydraulic control and treatment of the Ashumet Valley plume has been presented in a series of alternatives which are currently under public comment (14 July 1997 through 2 September 1997). Although the alternatives from both the Ashumet Valley plume and CS-10 plumes are undergoing separate review/comment processes, it is quite possible that the fence controlling the phosphorus piece of the Ashumet Valley plume will be integrated into the CS-10 treatment plant.
81	Dunn. & Kulis	AVPOI	In the event that remediation of the phosphorus plume is not included in the CS-10 treatment alternative, funds to support a program of rigorous monitoring of the phosphorus plume and its impact on the pond should be secured and put in place to ensure that remediation of CS-10 does not exacerbate the intrusion of phosphorus into Ashumet Pond. The United States Geological Survey (USGS) has completed an extensive program of research on migration of phosphorus in the Ashumet Valley groundwater, and has noted that injection of treated water into the Ashumet Valley aquifer could cause the currently sorbed phosphorus to flush rapidly into Ashumet Pond. Monitoring would help to guard against this adverse ecological impact.	Phosphorus contamination is not associated with the CS-10 plume. Phosphorus is associated with the Ashumet Valley plume which originates in the areas of the former waste water treatment infiltration basins and the former fire training area (FTA-1), each of which are closed. FTA-1 is undergoing remediation. Options for remediation of the waste water treatment basins are currently under evaluation. The hydraulic control and treatment of the Ashumet Valley plume has been presented in a series of alternatives which are currently under public comment (14 July 1997 through 2 September 1997). Although the alternatives from both the Ashumet Valley plume and CS-10 plumes are undergoing separate review/comment processes, it is quite possible that the fence controlling the phosphorus piece of the Ashumet Valley plume will be integrated into the CS-10 treatment plant.
82	Susan V. Walker	REPS	Our preference is for alternatives C1 and F. These alternatives have a high degree of plume capture and prevent some contaminants from migrating to the silts. The reinjection wells near Ashumet Pond will reduce damage on sensitive ecological habitats near the pond unlike alternative A. We are hopeful that access issues for alternatives C1 and F well be less likely to delay the project than alternative A.	Preferences noted.
83	Susan V. Walker	REPS	However, we are concerned that alternative F would operate at a total flow rate of approximately 9.1 million gallons per day But we do not see any negative rating about this in the evaluation matrix. so we are assuming there is no detrimental impact.	Alternative F is the most aggressive scenario proposed, and therefore has the greatest potential to impact the regional flow field. The alternative as modeled does not pass the hydrological thresholds. It is expected that design refinements of the selected alternative will lessen the simulated impacts to surface water bodies however it is not known whether Alternative F can be designed to pass all thresholds.
84	Susan V. Walker	REPS	We agree with the position of the JPAT that C1 would be improved with recirculating wells in the hot spot. Whatever alternative in chosen REPS expects vigilant monitoring to take place. Monitoring should lead to any necessary adjustments that are needed for plume capture, human health and ecological protection.	Preferences noted. A system perfomance and compliance monitoring program will be associated with any of the active system alternatives. This will enable adjustments in system operations to be made to enhance or improve performance. Examples of the scope of the monitoring efforts typical of the proposed remedial strategies are provided by the FS-12 (soon to go on line) and SD-5 (on line 4 August 1997) performance monitoring plans which have been developed in coordination with the regulatory agencies.
85	Peter F. Boyer, Town of Falmouth	General Public	1) Regardless of what alternative is selected to capture and treat the CS-10 plume, a long-term monitoring system should be installed downstream of the treatment train to check on the effectiveness of the treatment.	A system perfomance and compliance monitoring program will be associated with any of the active system alternatives. This will enable adjustments in system operations to be made to enhance or improve performance. Examples of the scope of the monitoring efforts typical of the proposed remedial strategies are provided by the FS-12 (soon to go on line) and SD-5 (on line 4 August 1997) performance monitoring plans which have been developed in coordination with the regulatory agencies.
86	Peter F. Boyer, Town of Falmouth	General Public	2) If, in spite of treatment, concentrations of VOC's exceeding the drinking water standard continues to flow downstream towards Falmouth's municipal water supply wells, the Department of Defense (DoD) must pay for wellhead treatment on those supply wells or provide an equivalent amount of water from uncontaminated sources at no charge to the Town. DoD must include this stipulation in the Record of Decision for CS-10.	The Department of Defense is committed to protecting or replacing water supply wells and it is stated in the Decision Criteria for CS-10 as part of the alternatives. The Record of Decision will also reflect the need and responsibility for such actions.
87	Peter F. Boyer, Town of Falmouth	General Public	3) The selected alternative should not destroy the research site in the sand pit west of Sandwich Road which has been used by the U.S. Geological Survey since the late 1970's to study the hydrology of the Cape aquifer in general, and the Ashumet Valley Plume in particular. If necessary, a small portion of the CS-10 plume should be uncaptured in order to protect the research site.	Our goal has been to develop alternatives that attempt to achieve 100% capture of the CS-10 plume. However, we have been evaluating impacts of CS-10 pumping strategies on the Ashumet Valley plume with an eye toward minimizing impacts to its trajectory and flow paths. As we move past the conceptual design phase toward detailed design we will be continuing to refine well screen placements, screen lengths, and pumping rates to further reduce any impacts to the Ashumet Valley plume and the U.S.G.S. research site. The possible need for a reduction in capture associated with the selected CS-10 alternatives to ensure minimal impacts to the Ashumet Valley plume has been discussed with the RPMs. In short, potential impact to the U.S.G.S. research site will continue to be a constraint that will be evaluated as investigative and modeling work are conducted to support detailed design efforts.
88	Peter F. Boyer, Town of Falmouth	General Public	4) The selected alternative should be cognizant of the close proximity of the Ashumet Valley Plume in the Sandwich Road area and, in particular, the phosphate portion of that plume The alternative should not cause large amounts of phosphate to be released into Ashumet Pond.	The hydraulic control and treatment of the phosphorus portion of the Ashumet Valley plume in the vicinity of Ashumet Pond has been presented in a series of alternatives which are currently under public comment (14 July 1997 through 2 September 1997). These strategies are designed to minimize potential migration of phosphorus to Ashumet Pond.
89	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	1. Based on the current plume configuration, it appears that the plume is being confined or directed into a definite flow path. Are there data available to show plume movement? If so, consideration should be given to optimizing the well spacing to focus on the plume main area and put less emphasis on the areas of the plume that are not moving.	There are no major preferential flow paths for the CS-10 plume. The groundwater model used to develop the conceptual plume response alternatives is based on field data. The field data consists of groundwater chemistry information collected over the course of several years and helps document and predict the movement of the plume.
90	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	2) Each alternative should include an analysis of site properties as a part of this evaluation to determine if each site is appropriate for the proposed alternative.	An in depth site analysis is required, but not at this time, because we have a conceptual representation of what the remedy may be. Once an alternative is selected an in-depth site analysis will be made on each parcel of property that is potentially impacted by construction.
91	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	3. In the evaluation of "hot spot', treatment, operating life and life cycle cost should be based on a shorter time period to account for the plume movement and treatment objectives.	The recirculating wells along the Northwest side of Ashumet Pond could be shut off after approximately five years because the groundwater contamination upgradient of the base boundary would be captured by the Sandwich Road containment fence, and the groundwater reaching the recirculating wells would no longer be contaminated. This strategy is reflected in the cost estimates for these alternatives.
92	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	4. A Decision Criteria summary table should be included to show a side-by-side comparison of all the options. An explanation of the selected alternative should also be added.	The table in the fact sheet titled "Analysis of CS-10 Plume Response Alternatives." (July 1997) and the "Summary Table for Alternatives Included in Decision Criteria Matrix Evaluation." is a table in the longer Decision Criteria Document, which explains how the matrix was completed by the RPMs. Both tables compare the percent capture of all alternatives. Several other tables appear in the Decision Criteria Document to compare all alternatives by various criteria. The matrix itself is a table which compares various features of all alternatives.
93	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	5. How is the percent of groundwater flux determined? Later in the evaluation it is stated that the interaction between the ponds and groundwater is not understood.	Pond flux is determined using the three-dimensional groundwater flow model. The model is an advective flow model. The model predicts the volume of groundwater that flows through each of the ponds under ambient conditions. Ambient conditions are those conditions that exist without the influence of the proposed plume response alternative stress. As part of evaluating the efficiency of each of the alternatives the model is used to assess the amount of groundwater that flows through the pond under stressed conditions. Stressed conditions attempt to replicate the stress due to extraction, reinjection and recirculating wells (depending on the alternative being tested). This modeled approach allows for a conservative approach in lieu of complete pond/groundwater understanding.
94	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	6. What is the expected depth of wells for each of the alternatives? Will they be screened the entire depth of groundwater? How will varying the screen depth affect the estimated pumping volumes?	The depths of the wells for each of the alternatives are generally very similar. The bottom of the wells range from - 80' below sea level to -190' below sea level. Screen lengths are based on the spatial distribution of plume contaminants (horizontal and vertical distribution), aquifer hydraulic characteristics, and goals of the design (trying to minimize potential impacts to surface waters and adjacent plumes). None of the alternatives utilize fully penetrating wells (wells screened across the entire thickness of the aquifer). The well screen depth is not directly related to pumping volumes.
95	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	7. The use of the terms "total plume volume" and "total plume mass" are not well defined.	Total plume volume refers to the volume of contaminated water, regardless of the concentration of contaminant within that volume. Only the water volume is measured and it is expressed in units such as liters, gallons or cubic feet. Total plume mass refers to the mass of contaminant only and ignores the water. It is expressed in units such as pounds or grams. For example, suppose a plume consisted of 10 liters of water with a TCE concentration of 1 milligram per liter (mg/l) and 10 liters of water with a TCE concentration of 10 mg/l. The plume volume would be 20 liters (equal to 10 liters plus 10 liters). The plume mass would be 110 milligrams (equal to 10 liters at 1 milligram per liter plus 10 liters at 10 milligrams per liter). If an alternative completely removed only that portion of the plume that was contaminated at 10 mg/l its effectiveness with respect to volume capture would be 50% (equal to the 10 liters captured divided by the 20 liter total volume). Its effectiveness with respect to mass capture would be approximately 90% (equal to the 100 milligrams captured divided by the 110 milligram total mass).
96	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	9. The use of the "7 days per year" for the human health risk criteria seems too low for this area. During the summer months, it is probably safe to assume that children will contact the water in the pond over a longer time period than seven days. FEC recommends that the time frame for dermal exposure to children (and possibly adults) be extended to at least 45 days, with 80-100 days being a more likely scenario.	The exposure factors used in the risk evaluations are have been developed with Massachusetts Department of Environmental Protection and U.S. Environmental Protection Agency and are currently the only exposure parameters that both agencies have accepted. In addition, the extremely conservative estimates of the concentrations of chemicals of concern in surface water, sediment, and the conservative assumptions regarding ingestion and uptake provide an cautious estimate of risk to human health.
97	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	10. It does not appear that the long-term impact of continual reinjection of chemically "sterile" water back into the natural ecosystem has been evaluated. It is possible that the ETR system is excessive, particularly if applied to all containment (capture) alternatives. It is understood that the dissolved oxygen deficit has been accounted for by the addition of oxygenated compounds; however, there are natural microorganisms, trace metals, and other nutrients that are removed during ETR treatment which cannot be recovered. According to conversations with AFCEE personnel, the loss of these other items is a trade-off for the remediation to be accomplished.	The reinjection of treated groundwater will be conducted at locations very close to the point of extraction. These wells will be located several hundred to several thousand feet from the nearest point at which an ecological receptor could reside. In the intervening space the treated groundwater will be mixing with the naturally occurring, uncontaminated aquifer fluids and will be reequilibrating with the minerals in the aquifer sediments. These two processes--mixing and reequilibration--will reinnoculate the treated groundwater and it should be indistinguishable from the native fluids before it would become available to an ecological receptor. In areas where ecological receptors are very near to the location of the plume (e.g., the Horseshoe Bend road area), recirculating wells which remove only the volatile organic compounds and add oxygen to the groundwater have been proposed.
98	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	11. The alternatives contain extraction fences which seem to be near hot spots that have been highlighted in other CS-10 presentations. Several of these fences (such as the northwest extraction fence) are defined as containment barriers for possible cross-contamination from other plumes. The placement of these fences may not actually represent hot spot cleanup.	The extraction fences and extraction wells shown in the conceptual well layouts have four purposes: 1) plume containment (i.e., to prevent the further migration of the plume), 2) to reduce the amount of the plume that is currently in areas of higher hydraulic conductivity (e.g., sand) from migrating into areas of lower hydraulic conductivity (e.g., silt), 3) removal of plume mass from within the plume, and 4) to maintain the flow of contaminated groundwater within the current footprint of the plume. The purpose of the Northwest Extraction Fence is to reduce the amount of the plume that is currently in areas of higher hydraulic conductivity from migrating into areas of lower hydraulic conductivity and to maintain the flow of contaminated groundwater within the current footprint of the plume. This well fence location happens to coincide with and capture of an area of higher contaminant concentrations. However its primary purpose is not "hot-spot" cleanup.
99	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	12. The risk calculations for ETR versus recirculating wells, natural attenuation, and other alternatives seem to indicate that "incomplete" capture still yields risk factors below the 10[-06] level. The purpose for the capture has not adequately been stated. Is the purpose to clean up to acceptable risk levels (such as 10[-06]), to clean up to the MCL, or to cleanup to the current instrument detection limit and technology limits during the clean up tme frame (such as over the next 50-100 years)?	AFCEE's plume containment goals are to capture 100% of each plume, where "plume" is defined as groundwater contaminated above maximum contaminant levels (MCLs) or other risk-based levels, and treatment of contaminants and cleanup of the plume to background levels if technically and economically feasible.
100	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	Alternative Rankings FEC has ranked the offered alternatives from the alternative most likely to provide adequate capture, clean-up, and workability (but not necessarily in terms of cost) to the alternative least likely to provide adequate capture, clean-up and workability. 1. Alternative F- Combination of recirculating and ETR; same as Alternative C but has extraction wells in the hot spot near Sandwich Road. This alternative seems to combine hot spot treatment, treatment at Ashumet Pond, and plume boundary treatment. It will probably cost the most, and may have some access issues at Ashumet Pond. However, up front costs to install more wells (primarily recirculation wells) may reduce the amount of time needed to treat the plume.'. 2. Alternative C- This alternative is essentially the same as Alternative F, but does not have the recirculating well hot spot treatment at Sandwich Road. The cost may be a little less, because the additional recirculating wells will not be installed, but the time for total treatment may be longer. There may be some access issues for the recirculating wells at Ashumet Pond 3. Alternative C- The difference between this alternative and Alternative C' is the shorter northwest extraction fence. Because the northwest extraction fence is shorter, treating some of the areas of higher concentration in the plume will not occur, and the plume will have to travel to the southwest extraction fence before it is captured. The cost for this system will be less than the above two alternatives. There still may be some property issues regarding the placement of recirculating wells at Ashumet Pond. 4 Alternate B- This alternative places an ETR fence at Sandwich Road, but does not treat any of the plume between Sandwich Road and Ashumet Pond. The northwest extraction fence (hot spot treatment for that portion of the plume) has also been eliminated This will be a cheaper alternative, and there will be no property access issues; however, will the public accept the fact that the portion of the plume going into Ashumet Pond will not be treated? This alternative may work if; · some nonintrusive form of treatment for the portion of the plume going into Ashumet Pond can be put in place, such as bioremediation, or · a really good public information program regarding the absence of human health and ecological risk associated with the portion of the plume going into Ashumet Pond can be established. FEC does not believe that the public will accept no treatment of the portion of the plume going into Ashumet Pond. 5. Alternative D- This alternative relies exclusively on the use of recirculating wells. Based on the United information regarding the efficiency of the recirculating wells, FEC does not believe this alternative will realistically capture and treat the plume to acceptable levels 6. Alternative A- This alternative relies solely on ETR treatment at the plume boundary, wherever it may be. FEC believes that the property access and ecological issues (associated with construction of the ETR) will be too great to overcome. 7. Alternative E- This alternative relies on natural attenuation to capture and treat the plume. Natural attenuation will not capture the plume; if it could, the plume would have not spread as far as it has. There is not enough information to rely on natural attenuation as a containment alternative. However, it may very well be that "Mother Nature" will eventually take care of the plume without interference from humans. FEC does not believe that the public will accept this alternative.	1. Assessment noted. 2. Assessment noted. 3. Assessment noted. 4. Evidence of recent studies indicate that CS-10 is under-flowing Ashumet Pond. 5. Assessment noted. 6. Assessment noted. 7. Assessment noted.
101	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	Prior to the development of the July 15, 1996 STRATEGIC PLAN prepared by AFCEE, the goal for addressing the plumes emanating from MMR were clear; essentially achieve 100% containment of seven groundwater plumes A detail review of the 60% design in the late Winter/early Spring of 1996 concluded that simultaneous implementation of the then proposed remediation systems would result in unacceptable adverse impacts to the hydrologic conditions in the MMR area. This goal was materially changed in the STRATEGIC PLAN, for example on page 8-7, "The design criteria will include treatment of extracted groundwater to as near as practicable to non-detect, subject to the constraints of technical difficulty or unreasonable cost. In addition, remediation goals for the plumes will generally be based on risk-based criteria or regulatory standards, such as applicable or relevant and appropriate requirements (ARARs). I believe these changes are important for they can have a significant impact on the decisions that are ultimately made to address the hi grounds Star plumes. For example inclusion of unsubstantiated alternatives and/or conservative cost estimates can result in the selection or serious consideration of an inappropriate alternative. Preferred CS-10 Plume Response Alternative. Although I have reviewed the fact sheets for the Alternatives included and not included in the Assessment, I will limit my discussion at the one Alternative, of those offered for considerations I would recommend for implementation at the site with the reservations noted in the lot section of this letter. It is my opinion that Foothills Engineering Consultants (FEC) provided a ranking and succinct commends that I generally agree with on the other Alternatives. It is my opinion, that of the alternatives assessed. that Alternative F- Combination of Extraction/Treatment/Reinjection (ETR) and Recirculating Wells (RW) would provide the most capture of plume contaminants and manage ecological and socio-economic impacts related to its implementation for the following reasons: 1. Because implementation will not occur until the summer of 1999, the zone of highest known contaminant concentration will have migrated downgradient from its current location to a point closer to Ashumet Pond, quite possibly beyond Sandwich Road (unfortunately, information regarding the location of the plume components at the time of implementation were not provided). This alternative provides important intervention and treatment of the area between the Pond and Sandwich Road and of the "hot zone" itself. 2. Use of RW systems will control impacts to Ashumet Pond. Review of Alternatives C, C1, and F appear to have similar installations near Ashumet Pond with the exception of the RW aligned along the area of the "hot zone", yet the matrix table on Page 4 and 5 of the Alternative Evaluation Matrix indicate the impact to the Pond to range from 0.5 feet for Alternative F to 0.2 feet in C1. At least two questions arise: 1.) What is the accuracy of the model in relation to actual conditions and 2.) Are we to believe that by adding the RW systems along the axis of the "hot zone" for Alternative F. will result in an additional 0.3 feet drop in Ashumet Pond as determined for Alternatives Cl a 0.3 foot drop in Ashumet Pond, with an area of about 202 acres, would be equivalent to about 19.8 million gallons of water? 3. This alternative can easily incorporate the existing pilot installations in addressing remediation of the 'hot zone'. 4. Active intervention of the plume has the potential of reducing the overall operating period of the remediaton system. The absence of this approach is discussed further in the next section of this letter. 5. The UVB pilot installation was very discrete and noise associated with its operation was barely noticeable and therefore would be well suited for use in residential areas (e.g. the area between thc Pond and Sandwich Road). 6. Costs are not significantly different than the range and accuracy of the costs estimate for the other alternatives, with the exception of Alternative E - Natural Alternation which for reasons discussed in the subsequent section of this letter is not viewed as an appropriate stand-alone alternative.	Point #1: Comment noted. Point #2, question 1: it is difficult to quantify model accuracy until the system has been started up and monitoring begins. The type of groundwater modeling is, however, the best available technology for evaluating hydrologic impacts of the types of plume capture systems being evaluated for these alternatives and incorporates geological information gathered over the several years of study of the MMR sites. The ongoing MMR ecological studies will help to refine the ecological target goals that have been set to date, and performance monitoring will help to identify modifications to pumping rates to help achieve cleanup goals while not exceeding ecological thresholds. Point #2, question 2: the wells included in the "hotspot" for alternative F were modeled as extraction wells, not recirculating wells. These additional extraction wells would pump approximately 650,000 gallons per day, putting additional stresses on the hydrologic system in the area. Greater pond level reductions would be expected. Recirculating wells would reduce this impact with some sacrifice in contaminant reduction performance. Point #3: Comment noted. Point #4: Comment noted. Point #5: Comment noted. Point #6: Comment noted.
102	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	1. It is my opinion that technologies to be considered in the alternatives analysis should consist of proven technologies for the conditions present and/or innovative technologies proven to be effective at the size by virtue pilot tests. This is the situation for both the ETR and RW technologies, however, it is not the case for natural attenuation (Alternative E). I am not aware of specific data to demonstrate that natural attenuation is occurring at the site and as FEC points out "Natural attenuation will not capture the plume; if it could, the plume would have not spread as far as it has ." Therefore, Alternative E should be eliminated from the decision matrix. Further, the inappropriate inclusion of this option gives the appearance that a viable alternative exists that is an "order-of-magnitude" less (ten times less) in cost, than the six other technically viable alternatives (not including the no action alternative). This is important in view of the changes mad by the STRATEGIC PLAN regarding the program goals "subject to the constraints of technical difficulty and unreasonable costs." I am concerned that the "stage is being set" to pursue natural attenuation despite the fact that I am not aware of any known site specific data to indicate it is a technically viable alternative.	Monitored Natural Attenuation has been a factor in the development of the plumes and has likely led to reduction of contaminant mass in the natural system since the contaminants were released. These processes are occurring both in the unsaturated and saturated zones of the subsurface. In addition, it is a component of all the alternatives in that it will be occurring during the operating life of any of the active remedial strategies to continue to reduce contaminant mass. However, in order to conservatively (worst-case) evaluate requirements to hydraulically control the plume we have used advective or physical transport modeling and assumed that processes of Monitored Natural Attenuation are insignificant. The EPA Superfund program allows the consideration of the Monitored Natural Attenuation option if compliance with standards will occur within a reasonable time frame, if adequate institutional controls relating to groundwater use are in place, and if monitoring will be occurring.
103	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	2. Assuming the life cycle cost presented in the Table on Page 32 includes the capital cost for each alternative, the O&M of the six alternatives, involving some form of groundwater treatment, represent about 63% of the total costs for a 20-year operating period. First, what are the total costs for the 30 to 50 year period noted as the potential term of treatment? Second, given the distribution of costs it is not clear to what extent, if any, AFCEE considered the financial implications of actively treating the plume to reduce the period for which treatment is necessary. While Alternative 101 through 106 (except no. 105) do address some in-plume treatment alternatives, has AFCEE given a closer look as to where in-plume intervention could reduce the overall treatment period and associated costs? While using the "containment system" to ultimately treat the groundwater plume may be viable, the period of operation and associated costs may be prohibitive (particularly if the 50 years of treatment is required). It is interesting to note that an approach to address plume remediation and containment is clearly more evident in the Ashumet Valley alternatives.	1. The cost for the 30 - 50 year period, if required would, as a minimum, stay constant. However, system and component life would begin to have higher cost impacts beyond 20 years. 2. The aerial extent of CS-10 rendered more aggressive remediation schemes problematic in massive pumping volumes and related high capital costs. Additionally, they were deemed to be more effective in mass removal in the initial years but did not effectively reduce total operating time.
104	Mashpee Selectmen, Nancy Caffyn	SMB Selectmen	3. Consideration of "institutional controls" to deal with off-site groundwater contamination has the appearance of being easy to accomplish given all effected properties would be provided with a potable municipal water supply. It is my understanding that institutional controls would require restrictions to be placed on property deeds. How does the AFCEE propose to do this? Does AFCEE expect consideration to be made to property owners as compensation for putting legal restrictions on the use of their property? If so how have these costs been factored into the cost estimates for the alternatives? In addition to the comments above, I generally concur with the comments offered by FEC regarding lack of critical data and of fate and transport information as related to understanding the long-term effectiveness of the alternatives under consideration.	AFCEE will work with local municipalities to impliment instutional controls such as: zoning adjustments, deed restrictions, public water hook up, and / or moratoriums on private well installation. If deed restrictions are needed, compensations could progress through the tort claims process or an internal process might be developed, if needed, for multiple properties. Since we cannot now state to what extent, if any, there will be costs for deed restrictions. It is not factored into the cost.
105	Ma. Division of Fisheries & Wildlife	General Public	The Massachusetts Division of Fisheries and Wildlife (MDFW) supports Alternative F (Hybrid Extraction-Treatment- Reinjection (ETR)-Recirculating Well System with In-Plume Extraction) as the preferred alternative, with Alternative C1 as a less preferred alternative. Alternative F is preferred by the MDFW because of the increased reduction in contaminants while minimizing ecological and hydrological impacts. The hot spot treatment using recirculating wells in the area near Sandwich Road is an important component of Alternative F. Alternative A (ETR System) is unacceptable due to potential impacts on Ashumet Pond from the extraction fence on the shores of the pond. Alternative D (Recirculating Well System) is unacceptable due to the complete reliance on recirculating wells. Alternatives E (Natural Attenuation) and G (No Action) are unacceptable because they do not reduce contaminant levels before they enter surface water bodies. Alternative B (ETR system) is less acceptable because it allows more of the plume below Sandwich Road to enter Ashumet Pond. The MDFW remains concerned about potential negative impacts of the phosphorus from the base's sewage treatment plume on Ashumet Pond. Any alternative for CS-10 must be monitored to ensure no increase in the phosphorus concentrations from the treatment system enters Ashumet Pond. Impacts on the vernal pools in the area need to be mitigated whatever alternative is selected. The MDFW is concerned about the reduced fish health (particularly the increased incidence of papillomas on brown bullhead catfish) in Ashumet and Johns Pond in comparison to reference ponds. More fisheries monitoring and research needs to be conducted to determine the causes of the impaired fish health in these ponds. A strong ecological monitoring component, including extensive fisheries investigations, should be an important part of any treatment alternative.	Preferences noted. Phosphorus contamination is not associated with the CS-10 plume. Phosphorus is associated with the Ashumet Valley plume which originates in the areas of the former waste water treatment infiltration basins and the former fire training area (FTA-1), each of which are closed. FTA-1 is undergoing remediation. Options for remediation of the waste water treatment basins are currently under evaluation. The hydraulic control and treatment of the Ashumet Valley plume has been presented in a series of alternatives which are currently under public comment (14 July 1997 through 2 September 1997). Although the alternatives from both the Ashumet Valley plume and CS-10 plumes are undergoing separate review/comment processes, it is quite possible that the fence controlling the phosphorus piece of the Ashumet Valley plume will be integrated into the CS-10 treatment plant. A detailed ecological monitoring program including development of baseline and long-term data for both Ashumet and Johns Ponds and a number of reference ponds has been developed to evaluate general pond health. This data will also be used to evaluate and monitor the operation of the selected remedial systems to ensure that the systems are not having an adverse impact on pond health. It is, however, our understanding at this time, that a number of factors, including use of pesticides and herbicides and agents to manage fish populations may be important in reduced fish health. It is our hope that the data developed through our ecological studies of the ponds in conjunction with other studies will help to resolve questions concerning current fish health.
106	Fisheries & Wildlife Board	General Public	As for CS-10 we recommend that alternative F be selected. This alternative appears to offer the best management strategy not only in stopping the plume but in protecting Ashumet Pond from major hydrological changes and subsequent impacts on fisheries resources. We recognize that the installation of recirculating wells at the ponds northwest shoreline may pose difficult negotiations with landowners. This access issue, however, would probably be even greater if an ETR fence along the Ashumet shore were installed under Alternate A. Also under Alternate A the reinjection fence is a considerable distance from the pond which could result in hydrological problems in maintaining satisfactory water levels in Ashumet Pond. The board would consider alternate C1 as a secondary option. We also believe that impacts on other wildlife resources will be minimal under either alternatives F or C1.	Preference noted.
107	Susan L. Nickerson	APCC	APCC has reviewed the alternatives and believes that Alternative B comes closest to meeting all the established criteria. We therefore recommend that AFCEE proceed with design and installation of Alternative B. It is also our strong feeling, and we wish to make this point very clear, that AFCEE should assume that any option that becomes the selected remedy for the CS-10 plume must have built-in flexibility. Clearly, modification will be needed, and must be anticipated and budgeted. Experience has shown that the actual location of the plumes is never entirely certain, and that the response of the aquifer or a plume to a containment system may not be at all what was expected or predicted by modeling. APCC therefore recommends strongly that part of the decision on CS-10 be to revisit and review the function of the treatment system on a regular basis and to make necessary adjustments to the system as its effectiveness becomes apparent.	Preference and concern noted. Monitoring is an integral part of a cleanup process and operation will be assessed regularly.
108	U.S. GEO SURVEY	General Public	The U.S Geological Survey respectfully requests that protection and preservation of the USGS Cape Cod Toxic Substances Hydrology field research site be considered in the selection of alternatives for the Chemical Spill 10 (CS- 10) and Ashumet Valley plume responses. The alternatives presented in the May 1997 and July 1997 fact sheets could, in many cases, seriously compromise or destroy this irreplaceable resource.	AFCEE recognizes the values of the USGS Cape Cod Toxic Substances Hydrology Field Research Site and will consider potential impacts on its future operations both during alternative selection and during final design of the chosen alternative. We encourage the USGS to reiterate the concerns expressed in their comments to the EPA, DEP, and public at large.
109	EG&G ENVIRON	Technology Vendor	1. Overall, the evaluation does not encompass a wide range of options with distinct differences. Based on the criteria rankings presented, the six active alternatives are very similar in terms of performance, cleanup duration, and cost. there is no clear advantage or disadvantage to any one alternative, For example, it would be beneficial if one alternative offered a greatly reduced cleanup time compared to the others. Of the six active alternatives, five are based on extraction, treatment, and recharge (ETR) and one on recirculating wells. The five ETR alternatives are very similar, differing only in where wells ate placed around Ashumet Pond and the length of the northwest extraction fence. Although not specifically stated in the decision criteria document, the decision process really appears to boil down to the following: a.) Should ETR, recirculating wells, or natural attenuation be used? b.) Assuming ETR is used, where should wells be placed around Ashumet Pond, and how long should the northwest extraction fence be?	Comment noted.
110	EG&G ENVIRON	Technology Vendor	2. The alternatives presented do not address aggressive treatment to maximize the rate of contaminant mass removal. All six of the active alternatives are variations on one theme -- plume containment. While certainly effective in preventing further plume migration, this passive approach writes off those properties presently contaminated and assumes that the affected residents are willing to wait several life times for the contaminants to dissipate. The six very passive active alternatives all wait for the contaminant mass to move to the wells rather than place the wells where the contaminant mass is. The supporting text in the decision criteria report estimates cleanup times of 50 to 100 years for all six alternatives. Given the long term duration of cleanup and the impact of operation and maintenance (O&M) costs on life cycle costs, additional alternatives which include aggressive plume treatment should have been included.	The alternatives that have been presented are aggressive and are in keeping with the goal of 100 % capture while minimizing impacts to sensitive environments. More aggressive approaches are possible however, they violate the ecological design criteria for the program (e.g. flux of treated water to ponds, surface water bodies and wetlands) and more importantly could result in ecological impacts. We have attempted to achieve a balance between capture of the plume and minimizing hydraulic and construction-related impacts to sensitive environments. Although, the rate of mass removal may be increased with aggressive approaches, in addition to violating ecological design criteria, they do not necessarily lead to a reduction in the time required to restore the affected portion of the aquifer to drinking water quality.
111	EG&G ENVIRON	Technology Vendor	3. The basis for eliminating plume treatment options from consideration appears to be unsound, It appears in the description of alternatives no longer under consideration that some alternatives involving in-plume capture plus downgradient capture were considered (e.g., Alternatives 101, 102, 104, and 106). It also appears that a common concern with these alternatives was the negative hydraulic impact of the in-plume wells (e.g., disruption of flow paths). Interestingly, all of these plume treatment alternatives used conventional extraction wells. Given the fact that one of the chief advantages of recirculating wells is the absence of hydraulic impacts, we believe that recirculating wells would have been more appropriate for in-plume treatment. Indeed, the recirculating well pilot tests have demonstrated the ability of recirculating wells to rapidly remove significant contaminant mass from plume "hot spots" without impacting groundwater flow. In addition, the discussion of considerations for Alternatives 101, 102, and 106 states that the impact of the in-plume extraction wells/fences "on the duration of plume cleanup is unknown at this time." Given the desirability of reducing cleanup times and the tremendous potential life-cycle cost savings, it seems unusual that in-plume treatment would be ruled out without this information.	The alternatives that were "parked" along the way either seriously violated the ecological design criteria or impacted the plume trajectories associated with the other plumes. We agree that recirculating wells are appropriate for in-plume treatment and have considered them as a refinement of Alternative C1 and we are continuing to operate the pilot test installations within an area of high concentration within the CS-10 plume for the purposes of mass removal. The Sandwich Road fence we have proposed as part of all the active alternatives except Alternative A is effectively an in-plume, equipotential fence which accomplishes both mass reduction, as well as capture. In addition, other approaches to in-plume treatment may be devised; however, although in-plume treatment may increase mass reduction for a period of time it does not necessarily lead to aquifer restoration to drinking water quality in less time than the proposed alternatives without considerable additional cost and potential impacts to sensitive environments.
112	EG&G ENVIRON	Technology Vendor	SPECIFIC COMMENTS ON EVALUATION CRITERIA AND RANKINGS The following comments address specific evaluation criteria and the bases for the criteria rankings. These comments are organized by the criteria numbers contained in the evaluation matrix. I.B -- Overall Protection of Environment 4. Very specific thresholds are provided to assign criteria ratings. Is there a scientifically defensible basis for these hydrological thresholds? For example, can it be shown that 0.6 ft change in ambient pond levels is significantly more harmful than 0.5 ft?	The design targets are scientifically based and have been developed in conjunction with the ecological TRET. They reflect an ecological conservative estimate of change that would minimize the potential impact associated with groundwater treatment systems. The scientific basis of the design targets are presented in the Work Plan for Ecological Assessment Associated with Groundwater Plumes and Remedial Activities at MMR (AFCEE 1997).
113	EG&G ENVIRON	Technology Vendor	5. If there is a defensible basis for these thresholds, is the groundwater flow model sufficiently accurate to make these determinations? For example, one of the hydrological thresholds is that no more than 25 percent of groundwater flux through the ponds may be injected water Alternatives A and B meet this criterion with a model- predicted flux of 24 percent while Alternatives C, C1, D, and F do not with model- predicted fluxes of 26, 34, 3O and 27 percent, respectively. If each of these results had an uncertainty of +/- 20 percent (which would probably be very good for this type of modeling), there would be no difference between any of these numbers. More likely, the models are only accurate to an order of magnitude. This is particularly true because of the uncertainty in model input data as pointed out by the AFCEE Expert Panel. Given the expected accuracy of the modeling results, a relative, rather than absolute, comparison of alternatives appears more appropriate In the example given in Comment No. 5, each of the alternatives would meet the threshold because the results are essentially the same. For the third threshold (change in groundwater flux) the results are -10, -9, -713, -5, ~0, and -10 percent for Alternatives A, B. C, C1, D, and F, respectively In this case, Alternative C is clearly different than the other alternatives and would not meet the threshold while the others would.	We concur that the uncertainty in the model results is approximately equal to or greater than the target values in many cases. However, the decision-making process should recognize the relative comparison of alternatives as much as the absolute value of any calculated target value. Presentation of purely relative evaluation results , however, would either deprive the reader of any estimate of absolute impact or invite similarly valid questions concerning the magnitude of the "acceptable" impact chosen as the reference point for the relative comparison. It should also be noted that the alternative evaluations are based on the calibrated model and represent a reasonable basis for estimating impacts. By presenting the absolute values for each alternative for the various targets, the relative ranking is evident and the reader is also able to make their own judgment on the significance of the estimated impact.
114	EG&G ENVIRON	Technology Vendor	III.A.1 and III.A.2 -- Capture of Plume Volume and Contaminant Mass 7. Model results are compared with effectiveness criteria for plume capture to determine rankings. What is the uncertainty associated with the nodal results? The model can only be calibrated to the existing conditions and there is no way to measure the accuracy of the predictions for future remedial alternatives.	The uncertainty associated with the model results cannot be calculated for a variety of reasons, including: · the uncertainty in the input parameters cannot be known · the possible combinations of model approximations with respect to lithologic detail, recharge variation, etc. are limitless Despite its many complexities and remaining questions, however, the aquifer is better defined than many other sites at which models have been successfully applied. Also, the calibration effort produced a generally good fit to the known data. We believe that the model results are sufficiently accurate to support decision making. It should be noted when reviewing such results, however, that many reported differences in effectiveness (for example, 88% capture versus 84% capture) are well within the uncertainty associated with the overall system definition and modeling process.
115	EG&G ENVIRON	Technology Vendor	8. A better explanation is needed of the effect of the low conductivity silt layers. It isn't intuitive that 67 percent of the plume volume and 61 percent of the contaminant mass would be caught in these silts in the absence of active remediation.	As the CS-10 plume travels from its source area, it sinks deeper in the aquifer until it approaches its discharge point to the ocean. The discharge area is located near the shoreline, which is still more than 3 miles distant from the leading edge of the CS-10 plume. The plume will continue to sink deeper for some distance. The aquifer materials tends to increase in silt content with depth and in many areas the bedrock is overlain by a basal silt layer up to 200 feet thick. Thus, as the plume migrates towards the ocean it encounters more low permeability materials in which the rate of plume travel decreases dramatically. Although the majority of the aquifer materials above elevation -70 (as a typical elevation) are high permeability sands, there are also some localized strata of low permeability silts that "trap" portions of the plume. Projecting 50 years into the future in the absence of remediation, it is estimated that approximately 2/3 of the particles representing the plume in the model would be migrating slowly through these low permeability materials.
116	EG&G ENVIRON	Technology Vendor	9. The volume of the plume captured by recirculating wells (Alternative D) appears low. The results of the CS-10 pilot test and the groundwater model calibrated to these results indicate essentially complete capture of the plume by recirculating wells.	The percent of plume volume captured for Alternative D is based on the modeling results from Alternative B because both alternatives have almost identical well layouts, with the exception of recirculating wells added near the Ashumet Pond shoreline for Alternative D. Given almost identical well layouts, the percent of plume volume captured by recirculating wells is nearly identical to the percent of plume volume captured by extraction wells. It was assumed that recirculating wells have similar capture as extraction wells.
117	EG&G ENVIRON	Technology Vendor	10. It isn't clear why assuming no attenuation is conservative. Neglecting attenuation will overestimate the rate of mass removal, overpredict the effectiveness of the alternatives, and underpredict cleanup times.	In order to conservatively (worst-case) evaluate requirements to hydraulically control the plume we have used advective or physical transport modeling and assumed that processes of Monitored Monitored Natural Attenuation are insignificant. Monitored Monitored Natural Attenuation has been a factor in the development of the plumes and has likely led to reduction of contaminant mass in the natural system since the contaminants were released. These processes are occurring both in the unsaturated and saturated zones of the subsurface. In addition, it is a component of all the alternatives in that it will be occurring during the operating life of any of the active remedial strategies to continue to reduce contaminant mass. Although retardation reactions may slow contaminant cleanup other attenuation reactions are expected to reduce mass. Consequently, the clean-up times predicted by the advective transport approach are reasonable to support the alternative evaluation phase of the project.
118	EG&G ENVIRON	Technology Vendor	III.A.3 -- Impacts on Other Plumes 11. The criterion rankings are the same for the ETR and recirculating well alternatives. These rankings do not acknowledge the advantage of recirculating wells over ETR with respect to impacts on other plumes. Minimal impact on other plumes is inherent in operation of recirculating wells, as has been demonstrated by the CS-10 pilot test and operations at other sites, ETR systems must be designed with careful placement of reinjection wells so that other plumes are not impacted. This design must be based on the results of groundwater models and, thus, there is some uncertainty in the effectiveness, Recirculating wells are, therefore, inherently more reliable in preventing impacts on other plumes.	Comment noted. However, ETR pumping strategies can also be designed to avoid impact to other plumes.
119	EG&G ENVIRON	Technology Vendor	III.C.1 and 2 -- Uncaptured Plume Volume and Mass 12. Criteria are presented for the volume of the uncaptured plume and the uncaptured contaminant mass. What is the difference between these criteria and the criteria for estimated capture of plume by volume (III.A.1) and estimated contaminant removal (III,A.2). These criteria seem repetitive and inconsistently applied. Under III.A.2, Alternative D gets a moderate rating for capturing 92 percent of the contaminant mass, yet under III.C.2 this same alternative gets a low rating for not capturing 100% of the contaminant mass.	We believe the criteria are applied consistently. Criteria III.A.1/2 deal with the overall effectiveness of plume capture, while III.C.1/2 deal with the characteristics of the "uncaptured" portion of the plume. In both cases, Alternative D has received a rating consistent with the rating criterion. Please note that the criterion rating for III.A.2 is based on capture by the active systems only, and does not include the contaminant caught in the low permeability silts.
120	EG&G ENVIRON	Technology Vendor	III.C.3 -- Persistence of Uncaptured Plume 13. The definition of this criterion indicates that it is based on the time for the plume to decrease to values that are no longer threats to human health or the ecology. The following discussion, however, suggests that the ratings are based on the time required to attenuate to below regulatory levels, which is different. The evaluations under III.B.1 and III.B.2 already indicate that the uncaptured portion of the plume does not pose a threat to human health or the ecology.	Comment noted.
121	EG&G ENVIRON	Technology Vendor	III.C.4 -- Surface Water Impacts 14. This criterion is based on the impacts of the uncaptured plume on human health and the ecology via the surface water pathway. It is unclear how this criterion is different than what was previously addressed under III.B.1 and 111.3.2 for human health and ecological risks respectively.	Sections III.C.4. which focuses on surface water impacts from the uncaptured portion of the plume is similar to sections III.B.1. and III.B.2 which describes the human health and ecological impacts associated with the uncaptured portion of the plume. The primary difference is under section III.B.1 the human health evaluation takes into account all exposure routes, which could include groundwater ingestion. However, for the CS-10 alternatives, ground water consumption has been eliminated through institutional controls. Therefore, for CS-10, both sections III.B.1 and III.C.4 are looking at the same exposures, the recreational uses of surface water bodies. The ecological evaluation in section III.B.2 is designed to quantify the potential impact in terms of a hazard index. In those scenarios where the plume related contaminants are below or attenuate to concentrations below a level of effect, then there is no longer a risk to ecological receptors and the calculated hazard index is below 1.0. In CS-10 this occurs resulting in the similarities in sections III.B.2 and III.C.4.
122	EG&G ENVIRON	Technology Vendor	IV.A.1 -- EDB Treatment Effectiveness The supporting text states "Recirculating well technology will not strip EDB from groundwater without special liquid-phase carbon treatment systems, which have not been included in this alternative." This statement is not accurate. Although EDB is not as volatile as other volatile organic compounds (VOCs) found at CS-10, it is still volatile. Under typical operating conditions for our recirculating wells' In-well EDB concentration reductions of 50 percent per pass may be expended from air stripping. The overall concentration reductions, considering recirculation, should be in the range of 75 to 80 percent. EDB is aerobically biodegradable, with a reported aerobic half life of about 3 months. Since recirculating wells oxygenate the effluent water to saturation, they will stimulate natural biodegradation of EDB within their treatment zones. This natural biodegradation should contribute an additional 80 to 90 percent per year concentration reduction The ability of recirculating wells to reduce EDB to background levels will, obviously, depend on the initial concentrations relative to background. It should also be noted that in-situ treatment options in addition h ex-situ liquid phase carbon are possible For example, in-well air sparging with ozone and hydrogen peroxide can be used to treat marginally volatile contaminants, such as EDB.	Comment noted. Stripping efficiency of EDB is low to moderate. However, neither case histories or performance data are available to provide a demonstrated basis for EDB treatment to MMR cleanup goals using recirculating well technology without modification of current designs.
123	EG&G ENVIRON	Technology Vendor	IV.A.2 -- VOC Treatment Effectiveness 16. The supporting text states "Recirculating well technology depends on VOC removal through air stripping which is less than 100% efficient." As dictated by the laws of thermodynamics, all treatment processes are less than 100% efficient. The criterion rating for Alternative D is very misleading, implying that recirculating wells are no more effective in treating VOCs than natural attenuation or no action. Recirculating wells are capable of treating the VOCs found at CS-10 to background levels, as has been proven in field tests elsewhere. If modeling shows that the system proposed under Alternative D does not treat VOCs to background, this is a design or modeling problem' not a limitation of the technology.	Sustained recirculating well treatment efficiency was determined to be approximately 97% as a maximum based on the results of the recently completed pilot test at CS-10 for influent concentrations of over 200 µg/L. The results of the pilot test did not indicate contaminant reduction to below detection, consequently it was not possible to rate the technology as equal to ETR in this respect. The text indicates that recirculating well technology achieves significant mass removal, and over time contaminant reduction is expected to approach non-detect. The text makes no comparison of the technology to Monitored Monitored Natural Attenuation or no action. The technology has been carried forth as a component of Alternatives C, C1, and F, as well as Alternative D
124	EG&G ENVIRON	Technology Vendor	IV.A.3 -- Semivolatile Treatment Effectiveness 17. The supporting text states that semivolatiles, if present, would not be removed without addition of external aqueous-phase carbon treatment..." As noted in comment No. 15 addressing Criterion IV.A.1, this is only one option. In-well treatment processes capable of removing semivolatiles are also possible.	Comment noted.
125	EG&G ENVIRON	Technology Vendor	V.A.3 -- Estimated Duration 18. All the active treatment alternatives involve treatment at the leading edge of the plume and all are expected to operate at least 50 and possibly as long as 100 years. This is so very long that it seems that shorter time frames would be desirable. Given the nature of the plume, the only possible way to reduce this time frame would be to install additional treatment wells in the body of the plume rather than only at the leading edge. The discussion of alternatives not carried forward indicates that wells could not be placed in the plume due to the effects on groundwater flow and plume direction. It appears, however, that only conventional extraction wells were considered. Recirculating wells could be placed in the plume without any hydraulic impact on plume migration rate and direction. Therefore, it would seem that placement of recirculating wells in the plume could result in significant reduction of the estimated cleanup duration. The additional capital costs could be more than offset over the life of the project by reduced 08M costs. Was this alternative considered by AFCEE?	Additional, in-plume recirculating wells are being evaluated for cost and performance benefits.
126	EG&G ENVIRON	Technology Vendor	V.B -- Reliability of Technology 19. The discussion of this criterion somewhat confuses reliability with level of experience. It is true that ETR has been applied at many more sites than recirculating wells. On the other hand, ETR performance at many of these sites was poorer than expected. The above-ground components of ETR (leg., activated carbon, air tripping) are very reliable, i.e., they produce consistent results. Due to the complexities and uncertainties, at geologic systems, however, the extraction and reinjection aspects of ETR are much less reliable. One need only look at the ETR pilot test experience at MMR where the plume was missed. The discussion of the criterion also does not recognize the significant differences between the proprietary designs comprising the category "recirculating well technology." There are significant differences between the complexity of designs arid, hence, inherent reliability.	The technology is taken as a whole (both the above ground treatment component and the ability to capture all contaminated water and subject it to treatment) in making the overall reliability assessment. The pilot tests and literature reviews suggest that the recirculating well layouts and screen settings are somewhat more sensitive to variations in lithology than ETR systems. For the same level of lithologic data, therefore, the reliability of a recirculation system as compared to an extraction system would be, in our opinion, somewhat less. We also believe that level of experience is a valid consideration in assessing reliability.
127	EG&G ENVIRON	Technology Vendor	V.C -- Coordination Requirements with Regulators and Other Agencies 20. The rationale provided in the supporting text seems insufficient to justify the criterion ratings. Specifically, the discussion states that "It is expected that ETR ... would not require extensive regulatory or agency involvement to obtain approval." On the other hand, "it is expected that full scale application of the recirculating well technology will require additional regulatory and agency involvement." Because the decision criteria matrix is reportedly a joint effort of EPA and MassDEP along with AFCEE, it would seem that such speculation concerning regulatory coordination should not be required.	You are correct. We will reconsider that assessment of recirculating wells.
128	EG&G ENVIRON	Technology Vendor	V.E -- Risks Associated with Construction 21. Alternative B is rated "Low Risk" and Alternatives A, C, C1, D, and F are rated "Moderate Risk." These ratings are very misleading. Because the main difference between Alternative B and Alternatives A, C;, C1, D, and F is placement of wells at Horseshoe Bend, the ratings imply that placement of these wells off MMR property poses a "moderate risk" to residents. While the risk to residents is obviously higher than if these wells were placed on base, the actual risk should still be minimal.	Comment noted.
129	EG&G ENVIRON	Technology Vendor	Vl Cost 22. The relative costs of Alternatives A, B. C, C1, and F are reasonable as these alternatives are so similar in terms of system components. The capital and O&M costs for Alternative D seem high. First, the total magnitude of the cost is quite high compared to estimates for full-scale systems provided by the NoVOCs technology vendor to AFCEE's contractor. Second, based on the total cost and reported number of wells, the full-scale per-well capital cost is higher than the per-well capital cost for the CS-10 pilot test. In reality, the per-well cost for the pilot test should be much higher than for full scale due to "lessons learned'' end economies of scale.	Alternative D cost estimates are based on knowledge obtained from the pilot tests conducted at CS-10, groundwater modeling results, pricing information received from two subcontractors, and engineering judgment. Pricing from the vendors did not include detailed lithologic and contaminant determination, access roads/site preparation, power supply performance monitoring, programmatic costs (management, health and safety, project controls, procurement, overhead etc.), and other items that were included in the Decision Criteria Matrix cost estimates for all alternatives. It should also be noted that the per well capital cost estimate for alternative D is substantially lower than the per well capital cost of the pilot tests.
130	CAPE COD COMMISSION	General Public	The treatment alternatives that have been forwarded for selection are generally the same in their attempt to reach the 100% containment design goal. Alternative B however appears to be the one that presents the least probable environmental damage and community obstacles. As such, it is the one most favored for implementation. While it does not capture as much of the plume as the other alternatives, it sets forth a reasonable interim action of containment upon which further actions, described below, can be taken.	Preferences noted.
131	CAPE COD COMMISSION	General Public	We need to remember that these thresholds were selected as a convenience for the containment modeling to proceed (see modeling comments below). The actual thresholds for impact on these sensitive surface water unknown. Especially since each ecosystem will have a threshold that is specific to its morphology and ecology. Therefore, it is not prudent to push the limit with these thresholds but to use them for comparative purposes. Since the other alternative push these limits they should not be selected unless it can be demonstrated that there is little cause for concern. If however the desire is to remove as much as we can now, then the recirculating wells technology of alternatives C1 and F which capture 1-2% of the plume particles could be pursued on the downgradient side to maintain the ecological threshold. Alternative B does not include the additional northwest extraction fence to capture plume particles that the model predicts will become captured in max time or the bottom silty areas. The silty areas are projected to entrap approximately 20% of the plume particles with a fail safe of the southwest fence should these plume particles not get caught in the silt. If the maxtime/silt process is real, then capture will be complete within the MMR boundary an area that will likely never be looked at as a potential water supply source. In a comparative sense, alternatives C1 and F have 6%, and the five Ashumet Valley alternatives have an average of 10%, of the plume particles ending up the maxtime/silt zone. So it appears that loss of the plume particles to maxtime/silt is unavoidable. Alternative B has the least amount of pumping nearly six million gallons per day. The other alternatives C1 and F have increased pumping by 20-30% respectively. The increase of pumping result in pushing the environmental thresholds and limit flexibility. Until there is more experience with the effectiveness of large scale pump and treat systems and their potential ecological impacts, pumping should be minimized. The treatment center however, could be sized with additional capacity to accommodate flexibility for further action beyond this interim action.	Comment noted.
132	CAPE COD COMMISSION	General Public	The northwest extraction fence serves another purpose besides its attempt to stop particles from entering maxtime/silt. That is faster capture. Alternative B will capture -60% of the plume mass in 10 years as compared to -75% for alternatives C1 and F. If the maxtime concept were a wash and the southwest fence was relied upon to contain that part of the plume which is truly moving, then more precise removal of additional hot spots within the plume could be considered. The CS-10 cross-section in the Date Gap report indicate distinct 100 ppb shallow and deephot spots that are some distance upgradient of the NW extraction fence. If faster plume capture is desired, then an alternative to capture these internal plume structures using minimal pumping should be considered. It is also clear from the data gap report that the CS-10 plume is a composite of several sources. A three-dimensional multi-source plume capture alternatives using the data gap information, should be compared to the single plume concept.	The single plume concept involving the modeling of a "plume shell" was developed as a composite of the multiple areas of higher concentration. It is understood that the plume is not one consistent uniform mass; however, by developing the shell we are likely to have overestimated the actual mass in the plume, but we believe this to be an appropriately conservative approach.
133	CAPE COD COMMISSION	General Public	The plume response alternatives have been designed and compared using a groundwater flow particle tracking model. This model was put together using the best information available and is a vast improvement over the 60% design model. However, the model is still only a coarse approximation of the natural groundwater system which has a high degree of variability. As such there is uncertainty for all the predictions; percent capture, mass removal, maxtime/silt, pond fluxes, particle path, and so on. This uncertainty is another reason for caution in regard to pushing the pumping to the ecological limits.	Comments noted.
134	CAPE COD COMMISSION	General Public	A particular issue concerning the model is the predicted capture times. The model assumes an initially seeded plume cloud will migrate by advective transport (groundwater flow) from their initial starting positions. However, portions of the plume will become re-contaminated due to the residual contaminants that don't migrate which continue to dissolve solvent into the gourndwater. Some laboratory bench tests have indicated that tens of pore volume flushes are necessary to remove contaminants. Therefore the predicted capture times could be off by at least 10 times.	The primary objective of the alternatives presented is to achieve the goal of 100 % capture of the plume. To meet the objective of controlling the plume, the most conservative or worst case modeling approach has been to assume that advective or physical transport is the critical parameter to characterize plume migration. This approach allows the AFCEE to evaluate how aggressive the pumping strategies will need to be, including expected location of fences, in order to attempt to meet the 100% capture goal. The persistence of the plume, within the limits of the capture systems, is dependent upon environmental fate of the contaminants: the kinetics of contaminant interaction with the aquifer media and how they are degraded by natural chemical, physical, and biological processes. Generally, the increased clean-up time, expected from processes of chemical transport retardation, is expected to be offset by processes of chemical, physical and biological degradation for the general levels of groundwater contamination we are dealing with in the CS-10 plume. However, it is our expectation that we will be conducting fate and transport modeling during detailed design work and prior to construction of the capture systems to develop refinements to our evaluation of cleanup times. We believe the current analysis is appropriate for comparison of the various alternatives.
135	CAPE COD COMMISSION	General Public	The main extraction and reinjection fence appears to run through the USGS research site. As I understand it this is one of three national research sites and many of the lessons learned from this site are being applied to the MMR clean-up and world wide. The use of this site and its association with a potential Environmental Technology Center as an incubator for economic growth should be considered. The decision criteria matrix has not dealt with this issue.	Our goal has been to develop alternatives that attempt to achieve 100% capture of the CS-10 plume. However, we have been evaluating impacts of CS-10 pumping strategies on the Ashumet Valley plume with an eye toward minimizing impacts to its trajectory and flow paths. As we move past the conceptual design phase toward detailed design we will be continuing to refine well screen placements, screen lengths, and pumping rates to further reduce any impacts to the Ashumet Valley plume and the U.S.G.S. research site. The possible need for a reduction in capture associated with the selected CS-10 alternatives to ensure minimal impacts to the Ashumet Valley plume has been discussed with the RPMs. In short, potential impact to the U.S.G.S. research site will continue to be a constraint that will be evaluated as investigative and modeling work are conducted to support detailed design efforts.
136	CAPE COD COMMISSION	General Public	Recent news items indicate that there will be revolving power outages in the future to deal with peak electric usage. How much energy is required to operate these systems and what is the approximate cost? Will energy to the treatment facility take precedence over domestic Cape-wide use? Following this, it seems that the existing recirculation wells which are achieving mass removal north of Sandwich Road should be left operating. But why does it cost $30,000 a day? Hopefully it is not all electric power usage.	The $30,000 per day was a newspaper error. It is $30,000 per month, and that is not all electrical power usage. As for revolving power outages, we can not say yet as to our total impact or our priority over domestic use.
137	CAPE COD COMMISSION	General Public	How has the impact of this containment strategy been compared to impacts on potential water supply withdrawals? And the other potential containment areas? How will the containment alternatives realign natural groundwater recharge areas to ponds? And coastal embankments? The communities have invested much time and effort to effect resource based environmental regulations. How will the containment alternatives change the resources? This information should be presented in a short report format for review.	Because all of the extracted water is returned to the aquifer after treatment, there will be no impact to the water balance of the aquifer. Additionally, the effects of drawdown and mounding are limited in extent and are anticipated to be within the range of natural water-table variations. Therefore, there are no anticipated impacts to the volume of water available to potential water supply wells nor are any impacts anticipated that would be related to changes in water levels to potential water supply wells. An integral part of the alternatives screening process is the evaluation of the effects of a particular alternative on nearby plumes. The effects on nearby plumes is evaluated through the use of the computer model. Alternatives were either modified to reduce the impacts to other plumes, or "parked" if the impacts were too great. These alternatives are described in the section of the document titled "Description of Alternatives No Longer Under Consideration". The alternatives will affect the natural groundwater recharge to the ponds due to the close proximity of system components (i.e., extraction, reinjection, and recirculating wells) to the ponds. Ecological screening goals were developed to evaluate the effects of the alternatives on the ponds. The conceptual designs of the alternatives were modified to meet the ecological screening goals where possible. Adverse effects to the ponds are not anticipated if the ecological screening goals are met. Operation of the CS-10 alternatives is not anticipated to affect coastal embayments due to the distance between the possible systems and the coast. If the ecological screening goals are met, adverse impacts to the groundwater and surface water resources are not anticipated. Regardless of the alternative chosen, monitoring of the sensitive ecological areas potentially impacted will be performed. Adjustments to the system would be considered if impacts are confirmed. Information regarding the potential ecological impacts related to the alternatives is summarized in the Decision Criteria Document. A Performance Monitoring Evaluation (PME) plan to address system operation and potential impacts on ecological settings will be prepared. An additional report specifically addressing CS-10 ecological impact evaluation during the conceptual design process is not planned.
138	MA Depart of Public Health	MA DPH	This letter is regarding comments relative to the proposed CS-10 Plume Response Alternatives. Based on the options presented and consideration of the various threshold criteria, it is the opinion of the Bureau of Environmental Health Assessment (BEHA) that the best option for the remediation of CS-10 is Alternative B with minor adjustments. The primary decision point in this opinion is that recirculating wells should not be utilized to capture a plume, or used at the edge of a plume, unless you can accept incomplete contaminant treatment. The information evaluated suggest that recirculating wells are good at reducing hot spots and limiting hydrological impacts. However, the ability of these systems to completely reduce contaminants is limited by the recirculation of treated waters into the recirculating well cell. Also, it is not clear that the size of the recirculating well cell can be clearly delineated. This makes the use of recirculating wells subject to plume escape due to uncertain recirculating well spacing on a recirculating treatment fence. On this promise, BEHA has rejected the use of Alternatives C, C1, D, and F. Alternatives A, C, C1 and F all appear to have significant impacts on the Horseshoe Bend neighborhood and it appears that these people are bearing a disproportionate burden for the military's activities. Also, it is not clear what impacts these systems will have on the neighborhood and what, if anything, the Air Force will do to minimize impacts. Other issues that are not clearly addressed in the decision criteria are the impacts of the removal of remediation systems on ecosystems and habitat and the costs associated with these removal activities. Alternative E does not appear to be protective of public health, the environment or the prudent maintenance of the water resources of Upper Cape Cod. Based on the above comments, Alternative B is the only remaining option that seems viable. Although we are not fully satisfied with this option we believe it does have some strengths. Alternative B presents a very limited number of property access concerns. There is a lower risk to human health during system construction of Alternative B. Construction and operation of alternative B would have a lower socio-economic impact on nearby areas. The performance of Alternative B could be enhanced with continued operation of the recirculating wells on Simpkins Road and perhaps by the installation of some recirculating wells in the "northwest" area of the plume hot spot. Recirculating wells in these areas would increase mass removal and the overall performance of option B. Lastly, we are not sure of the construction schedule, but you may want to consider begining work in the Sandwich Road area and work towards the northwest, thereby reducing the potential for off-base contamination first.	Preferences noted.
139	MA Natural Heritage End Species Program	General Public	The Natural Heritage and Endangered Species Program ("NHESP") has reviewed the CS-10 Response Decision Criteria Document and would like to offer the following comments regarding potential impacts in state-listed rare species. The information provided in the Response Decision Criteria Document indicates that many of the proposed alternatives may impact rare species. It appears that Alternative A may have the greatest impact to rare species due to the close proximity of the proposed extraction fence to the Ashumet Pond shoreline. However, it the opinion of NHESP that, with regard to rare species concerns, the AFCEE/EPA/MassDEP team may proceed with any of the proposed alternatives if adequate mitigation is proposed for impacts to these species. The Response Decision Criteria Document addresses project design and rare species impacts in general terms. NHESP will need to review more detailed project plans, a quantitative assessment of impacts to rare species and their habitat (including more details on hydrological impacts to Ashumet Pond) and a comprehensive mitigation plan before making its final determination.	Non-preference noted. AFCEE will continue to work with NHESP on development of potential mitigation activities.
140	Ed Crosby	Neighborhood	He favors alternative A.	Preference noted.
141	Frances T. Kane	General Public	I support the recommendation assessments and comments submitted by Woodard and Curran and Foothills Engineering Consultants on behalf of the Town of Mashpee. I am deeply concerned that real estate will suffer dearly during the cleanup process. The cost of reimbursing owners who sell their property at a loss should and must be considered as an added cost to MMR cleanup.	Preference noted. The Air Force can only compensate fair market value for property value for property required to conduct the remedy. Any claims as you mentioned should be addressed under the Federal Tort Claims Act.
142	Kathryn M. Hess USGS	General Public	These technical comments are in addition to the letter sent to James Snyder, dated July 29, 1997, in which my USGS colleague Denis LeBlanc outlined concerns over the effects of the proposed alternatives on the USGS Cape Cod Toxic Substances Hydrology field research site. EFFECTS OF ALTERNATIVES ON POND FLUXES: The estimates of pond flux are extremely sensitive to the hydraulic parameters and boundary conditions used in the ground-water flow model to represent the physical boundaries between the ponds and the ground-water system. No attempt has been made to present the uncertainty in these critical calculations. A sensitivity analysis needs to be added before the effects on pond flux of the proposed alternatives can be adequately evaluated. A threshold criteria that no more than 25 percent of the flux through a pond could be treated water was established out of concern that water discharging from an activated carbon treatment facility would be so clean, with all of the natural dissolved organic carbon removed along with the contaminants, that the treated water could adversely effect the ecological health of the ponds. Most of the active alternatives fail this threshold criteria and those that do pass (A and B) do so only barely (24 percent). All of the alternatives that fail include recirculating wells. I suggest that the criteria is being improperly applied by including both water that discharges from the ETR systems and water that passes through the recirculating wells. The air stripping treatment process of the recirculating wells will not have the same polishing effect as does the activated-carbon process of the ETR systems. The accounting of the pond flux could be modified to keep track of three quantities: flux from ETR systems, flux from recirculating well systems, and flux of untreated ground water. I suspect that many of the alternatives would pass the pond-flux threshold criteria if it were applied only to ETR discharge.	Because "true" pond fluxes are not known, they were not calibration targets, consequently, only limited sensitivity testing was done during calibration. One such test increased horizontal and vertical conductivities by a factor of 30, with the corresponding change in computed pond fluxes varying from approximately 10% to 100%. For Snake, Ashumet, Johns, and Coonamessett Ponds the fluxes varied from 10% to 45%. Changing only K values in the model results in a general decrease in the hydraulic gradient, thus damping to some degree the resulting impact on pond flux. The sensitivity results will be described in more detail in the Draft MMR Plume Response Program Groundwater Modeling Report (in progress). Although not simulated explicitly in sensitivity runs for the final calibration, changes in the number of layers used to simulate a physical boundary between a pond and the aquifer were examined during the calibration. In terms of the absolute value of the pond flux, an uncertainty factor of 100% is indicated by sensitivity testing. Because of the general similarities in the re-injection rates for the ETR alternatives tested, however (approximately 20% range in reinjection rates), the relative ranking of the alternatives is not expected to change. Regarding the second part of the comment, we agree that the methodology neglects to account for the benefit of the re-circulation wells with respect to maintaining ambient water quality (except for volatiles) in the reinjected water. Given the narrow range of computed fluxes relative to the target of 25%, it is also possible that some other alternatives would meet the target value if the ETRs were considered separately from recirculation wells, as suggested. Consideration of Runs A, B, and C, however, suggest that the revision would only be a few percent. In alternatives A and B there are no re-circulation wells and the computed percentage of treated water into the pond is 24% in both cases. When recirculation wells are added to the mix, as in Alternative C, that percentage only increases to 26%. This increase is well within the general uncertainty of the modeling and within a range consistent with the range of total re-injection rates in the three runs (7.5 MGD in Alternative C versus 7.2and 6.9 MGD in Alternatives A and B, respectively). In alternatives C, C1,and F, the re-circulation component of the Alternative is minimal and would not greatly affect the computed values. Rather than revise the calculation methodology, we suggest noting that the computed values are well within the uncertainty range of the method. For Alternative D (composed only of recirculation wells), the calculated amount of treated water as a percentage of pond flux should not be revised. However, it should be noted that the potential negative impacts of re-injecting water from re-circulation wells are less than from ETR systems.
143	Kathryn M. Hess USGS	General Public	CAPTURE FAILURE: Every response alternative fails the primary balancing criteria of 95 percent capture by volume. Only the two new alternatives (C1 and F) that have extraction wells within the plume reach 90 percent removal by mass. This is achieved by capturing more contaminants before they have a chance to migrate deeper in the system into lower-conductivity layers. Most of the volume/mass estimated not to be captured remains or becomes "trapped in low-conductivity silt deposits." The distribution and hydraulic properties of these deep sediments is not known well. As I argued above with the modeling of the ponds, a sensitivity analysis should be performed. The sensitivity of the model results to the distribution and conductivity of the low-conductivity silts should be considered in the evaluation of the response alternatives.	We acknowledge that the distribution and conductivities of the deep sediments is not well documented. As part of the calibration, two sensitivity runs which varied anisotropy with depth were performed. These runs would be similar to having more low K sediments with depth but would not test variations in the distribution of low K sediments. These two runs decreased the anisotropy below sea level by : (1) a factor of 2 (i.e., increased K in the vertical direction) and (2) by a factor of 20 between sea level and elevation -50 and by a factor of 2 from elevation -50 to elevation -100. Both sensitivity runs produced results similar to the calibration run and to observed heads and plume distributions. Because plume paths and flow fields were similar for the calibration sensitivity tests and the ETR systems minimize changes to the flow field by design, it is expected that these sensitivity results are applicable to the alternatives evaluation as well. The sensitivity results will be described in more detail in the Draft MMR Plume Response Program Groundwater Modeling Report (in progress). There is considerable similarity in the layout of the extraction and re-injection wells between the alternative ETR systems presented in the decision matrix. The similarities between the ETR alternatives and the sensitivity results described above suggest that variations in the conductivity of the deeper sediments would not significantly alter the relative comparisons between alternatives. Conducting sensitivity runs on the distribution of low K sediments would be problematic, given the infinite number of possibilities that could be imagined. We believe that such sensitivity runs would be less beneficial or cost-effective than the approach proposed in the ETR Data Collection Plans already submitted (FS-12, SD-5N, CS-10). That is, additional borings to obtain detailed lithology will be performed and selected boreholes during construction will be tested to identify if the aquifer lithology and K distribution in the plume area is significantly different than that assumed. Testing of aquifer response during system startup will also provide reliable data on aquifer properties and system performance will be monitored over time to continually improve our understanding of the aquifer.
144	Kathryn M. Hess USGS	General Public	SOUTHERN FENCE LOCATIONS: The description for alternative B lists as a benefit that all the installations are on MMR property, thus reducing anticipated property access issues. As drawn on the map the southern extraction fence and the main reinjection fence extend to the south of the MMR through the gravel pit where the USGS maintains an intensive ground-water contamination research program on Massachusetts Department of Fish and Wildlife property. To remain on MMR property these fences need to be moved to the north.	The well layout as shown does extend south of MMR. That layout was based on an estimate of the plume boundary that has been shown by subsequent sampling to be too far to the southwest. The anticipated layout at this time is farther northeast and entirely within the MMR boundary. We recognize the potential impacts on the USGS research area due to ETR well placement and will work during the final design to keep all system components on MMR property.
145	Kathryn M. Hess USGS	General Public	TIME SCALES: A fifty year time scale is used to calculate the capture efficiency; a twenty year time scale is used in the cost analysis. If the systems are expected to operate for 50 years, then the cost analysis should be for 50 years also. Labeling the summed costs "Life cycle cost" on the evaluation matrix is misleading when they sum costs over only 20 years. A consistent time frame would facilitate making consistent comparisons.	While the term "life-cycle costs" may be misleading the cost comparisons are presented for comparison of alternatives, not as an absolute measure of the total cost of plume response actions. The 20-year operating life was selected to correspond to the life-cycle used in the IROD to maintain consistency between the documents. All alternatives included in the CS-10 Decision Criteria Matrix have similar expected cleanup durations, as explained in criteria V.A.3.
146	Kathryn M. Hess USGS	General Public	RECIRCULATION: In many of the alternatives long reinjection fences run parallel to the extraction fences. The spacing between these fences appears to be only a couple hundred feet. What percent of the water captured by the extraction wells is estimated to be from the injection wells? Has this been evaluated?	Where property access permits, reinjection wells are closely spaced to the extraction wells and are parallel with the extraction wells. The purpose of this type of configuration is to minimize the effects of drawdown and mounding, and subsequently reduce the impacts of an alternative on the ecosystem and overall flow through the aquifer. The trade-off for this type of configuration is that some of the water captured by the extraction wells is from the reinjection wells. The percent of water from reinjection wells that is captured by the extraction wells has been evaluated as part of the evaluation process and the alternatives were modified to reduce the amount of "recirculated" water. The amount of water that is "recirculated" for the conceptual designs is in the range of 20 to 30%. One of the goals of the final design process will be the reduction of "recirculated" water to the extent practical.
147	Kathryn M. Hess USGS	General Public	RECIRCULATING WELLS: No alternative includes keeping the pilot recirculating wells operating in the region of high contaminant concentrations just north of Sandwich Road. At a minimum keeping these wells operating may be a way to reduce the amount of mass that moves beyond the planned installations between now and when the new systems begin operating.	The recirculating wells are continuing to operate beyond the pilot test period and are being considered for continued operation between now and full system start up. As such they may be considered as a refinement to the alternatives presented.
148	Kathryn M. Hess USGS	General Public	DESCRIPTION OF ALTERNATIVES IN THE THIRD DIMENSION: Only mapped views of the response alternatives are presented. These contaminant plumes are three dimensional. It is difficult to evaluate these alternatives without information about their vertical dimensions.	Vertical dimensions were made available in the general fact sheet about the CS-10 plume.
149	Greg Yaylor	JPAT Member	Same as Town of Mashpee (comments 91-107)	Same as Town of Mashpee (Responses 91-107)