SD-5 South Posterboard Session and
Public Meeting
Agenda Item # 1. Welcome, Introductions and Groundrules: Mr. Sobel welcomed the attendees to the meeting and stated that the purpose of the meeting was to discuss Storm Drain 5 South (SD-5 S) and the considered remedial alternatives. Mr. Sobel introduced the panel which consisted of the Remedial Project Managers (RPM’s); Mr. Pinaud of the Massachusetts Department of Environmental Protection (DEP), Mr. Marchessault of the United States Environmental Protection Agency (EPA) and, Mr. Snyder of the Air Force Center for Environmental Excellence (AFCEE). Mr. Sobel explained that the meeting was jointly sponsored by the three agencies represented at the table. He explained that AFCEE was the lead agency involved in the clean up work taking place at the Massachusetts Military Reservation (MMR). He went on to say that Mr. Pinaud and Mr. Marchessault worked closely with AFCEE in making decisions about how to address each of the plumes. He went on to say that the panel members played a key role in the decision process and were available to provide information to the public about the alternatives that were being considered for the SD-5 South plume. He also stated that the panel was asking for public input and advise. Mr. Sobel commented that the attendees would have an opportunity to make comments and ask questions following Mr. Snyder’s presentation. Mr. Sobel asked the attendees to please raise their hand when they wanted to speak and to introduce themselves. Agenda Item # 2. The Groundwater Recharge Process: Mr. Snyder displayed an overhead image of Cape Cod (see attached) which depicted an area referred to as the Sagamore Lens. He explained that the Sagamore Lens was an aquifer that supplied water to the Upper Cape. He also said that when precipitation percolated through the sand and reached the water table it would then contribute to the water supply. He stated that this process was referred to as the groundwater recharge process. Mr. Snyder went on to say that a contaminant introduced by such occurrences as a spill or a broken pipeline would then be carried down by precipitation into the water table and migrate downhill with the flow of the water. Agenda Item # 3. Groundwater Treatment Technologies: Mr. Snyder said that there were two technologies considered in addressing groundwater contamination. Extraction, Treatment, Reinjection: Mr. Snyder explained that Extraction, Treatment, Reinjection (ETR) was also referred to as pump and treat. He said that a typical ETR system consisted of three basic components. The first step would be to pump groundwater out of the aquifer using a series of extraction wells. Next, the extracted water would be treated in an above ground carbon treatment vessel where the carbon filters removed the volatile organic compounds (VOC’s). The final stage was to pump the treated water back into the aquifer through a series of reinjection wells. The water would be reinjected in an area outside of the contamination because it would now be clean water. However, the reinjected water would be kept fairly close to where it was extracted from to maintain the hydraulic balance. Recirculating Wells: Mr. Snyder said that pilot testing had been done on recirculating wells in the past year. He stated that recirculating wells were also a pump and treat technology but that they were specialized so that they could be used in a sensitive area to avoid anyhydrological impact. Mr. Snyder explained that recirculating wells extracted groundwater from the bottom of the zone and mixed it with air as it rose through the well at which point the VOC’s would have a tendency to volatile with the air with which it was mixed. The air would then went to the above ground carbon treatment center and where the air was filtered. Mr. Snyder went on to say that in the test pilot the air was reused by being reinjected in to the ground. He also said that the water that was air stripped was dropped back down to create a circulation zone. Agenda Item #4. SD-5 South: Mr. Snyder then displayed a transparency of the SD-5 South Plume Base Map (see attached) and pointed out the base boundary, the housing area, the cemetery, routes 151 and 28. He also pointed out Land Fill-1 (LF-1) and Chemical Spill-10 (CS-10). He then displayed a close up map of SD-5 South and pointed out the extraction system in operation. He also said that there was a treatment plant in the immediate vicinity as well as reinjecting wells. He stated that the plume was being treated at this point (SD-5 North) and began operation in August of 1997. He then showed where the plume originated on base property as well as a depiction of an exaggerated cross section of below surface of Johns Pond (see attached). Mr. Snyder stated that this showed the plume and how it was pushed down by groundwater recharge. Mr. Snyder stated that the decision criteria process (see attached) examined questions and evaluative criteria which allowed the alternatives may be compared to one another based on analysis of impacts to ecological receptors, the human health risk, and impact from construction. Mr. Snyder then said that the document for SD-5 South was out for public review and comment. He went on to say that the public comment period ended on November 21, 1997 and that all comments submitted by the deadline would be responded to in writing. He also said that the decision was due to be announced on December 15, 1997 and that following the decision would be the implementation of that decision. He then said that June 1999 was the date of operation for whatever alternative selected. Mr. Snyder told the audience how to submit written comments (see attached). Mr. Snyder displayed an aerial map (see attached) depicting the survey that tied together the data which would located the plume and provided an idea of the surface features of where the plume was located. Mr. Snyder said that there were ecological design targets (see attached) that equated how the different alternatives would effect the plume if different pumping scenarios were used. He said that there were computerized models used to simulate the pumping effects on the water and that these show how the effectiveness of the wells in terms of how much was captured and also how much the water table would be drawn down in that area as well as how the regional water flow may change. He went on to say that possible impacts from the pumping were taken into concern. He also stated that all of the alternatives had meet the ecological design targets. Fate of Contaminant Mass (no action) Mr. Snyder displayed a transparency depicting what would happen with SD-5 South if no action was taken (see attached). He said that it was believed that Johns Pond would have some interaction with the water in that area and that 76 percent of the plume mass would eventually end up in Johns Pond. He also said that three percent would be captured by the system already in use for SD-5 North. SD-5 South Plume Field Work (see attached) Mr. Snyder stated that data was recollected and 18 wells were sampled in the last ten monthsin preparation for the development of the alternative. He then said that the results from the sampling were back in September and that the data was validated in mid September. Mr. Snyder went on to say that the concentrations of contaminants in the plume were then confirmed. He also said that the overall results from the 1996 data (see attached) showed the maximum concentration from the following compounds; trichlorethylene (TCE), tetrachlorethylene (PCE), ethylene dibromide (EDB), and dichloroethylene (DCE). Mr. Snyder then said that the latest tests showed TCE at 43 parts per billion (ppb) and PCE as 4 ppb. He then displayed a transparency showing the maximum concentrations of SD-5 North (see attached). Agenda Item # 4 . The Alternatives: (see attached) Alternative A: Mr. Snyder said that alternative A included extraction and reinjection wells along Hooppole Road as well as extraction wells along Highland Avenue. He then pointed out the extraction wells and the reinjection wells that would bepumping the clean water back in and he also pointed out where the recirculating wells were to be located. He stated that there may be recirculating wells installed between Hooppole Road and the pond shore line. Alternative B: He explained that alternative B was extraction and reinjection wells along Hooppole Road and would be a less complicated construction alternative. Alternative C: Mr. Snyder said that alternative C consisted of recirculating wells along Hooppole Road these wells would have the greatest influence on the plume in that area. Alternative D: Mr. Snyder said that alternative D was the use of extraction wells spread throughout the body of the plume and reinjection wells at points along the outside of the plume. Mr. Snyder explained that each of the mentioned alternatives were similar in effectiveness as noted in the matrix (see attached). Alternative E: Mr. Snyder said that alternative E was the last of the active alternatives and would consist of recirculating wells spread throughout the body of the plume. Natural Attenuation: Mr. Snyder stated that the last alternative being considered for SD-5 South was referred to as natural attenuation. He explained that this would be a monitoring approach which would project the course of the plume. He then said that natural attenuationwould still be submitted to institutional control such as hook-up to public water for residents who lived where the plume migrated. Mr. Snyder said that "no action" was also an alternative to be considered and was used as a comparison to the other alternatives. Mr. Sobel said that there were several ways to submit comments into the decision process and that comments would be accepted shortly. He then said that Mr. Pinaud, Mr. Marchessault and Mr. Snyder would listen to the comments and note the information provided. He again mentioned the ways in which to submit comments outside of the meeting. Mr. Sobel also said that if a formal comment was submitted there would be a response in writing (responsiveness summary) that would come out at approximately the same time as the decision. He went on to say that Ms. Amy Brand of CH2M Hill was available tonight to take formal comments. Agenda Item # 5. Questions and Answers: David Dow of the Sierra Club asked what the concentration of the contaminants would be if, in a worse case scenario, all of SD-5 South discharged into Johns Pond. Mr. Perry, the project manager for the SD-5 South, said that it had been calculated that if all of the existing contaminants in the plume were suddenly mixed with the pond water, contaminants would still not be detected in the pond. A resident of Mashpee asked what kind of wells were in the SD-5 North system and asked if there was any available data. Mr. Marchessault replied that the wells that were installed were the ETR as opposed to the recirculating wells. He also said that 10 extraction wells and 8 reinjection wells were installed and the data from the operation had yet been seen as it does take some time for the system to stabilize. He went on to say that the contaminate was coming in at a very low level. Mr. Snyder said that the ten extraction wells acted as a "wall" or barrier. He said that the monitoring wells had just begun to be tested to help determine how well the system was working. Mr. Snyder said that it was still very early in the process. Ms. Caffyn asked if Mr. Snyder was referring to only one type of well. Mr. Snyder answered yes, that he was referring to the standard extraction well which used the carbon treatment plant. Mr. Sobel asked if there were two types of wells being considered forSD-5 South. Mr. Snyder replied that standard extraction wells and recirculating wells were being considered. A member of the audience asked if the data from the SD-5 North wells was being used to determine what type of wells would be used for SD-5 South. Mr. Snyder said that recirculating wells were an innovative technology and that they had been test piloted at CS-10. He went on to say that the tests had been used to determine how best to use the wells and what design would be most efficient. He alsosaid that the data was some help but that the final design would hinge on what was found at the exact location. Mr. Theis recommended coordinating other construction activities that were needed in Mashpee with whatever construction that may occur with the selected alternative. He said that he would submit specific ideas as a later time. Ms. Caffyn said that the design for the selected alternative would not be complete until 1999 and asked how far the heavier concentration of the plume would travel south by then. Mr. Snyder replied that approximately 30 percent of the plume mass would go by within that time frame. Ms. Caffyn said that about 30 percent would be going into Johns Pond and asked Mr. Snyder if he perceived that to be any kind of a health or ecological problem. Mr. Snyder stated that perhaps four gallons of VOC’s would end up in Johns Pond. He went on to say that four gallons of VOC’s mixed in with the amount of water in Johns Pond would still be a very low detection. He also said that this study showed that SD-5 South was traveling towards Johns Pond but that levels of contaminants diminished as they moved up toward the pond bottom. Ms. Caffyn asked if any sampling of fish, sediment or fresh water shells was done to establish that there had not been any accumulative damage to the pond itself. Mr. Snyder replied that sediment sampling had been done and that there were no VOC’s found. Mr. Minior stated that in 1993 and 1994 study of Johns Pond fish and sediment sampling were conducted and nothing was found at that time. Ms. Caffyn said that she felt that fish testing should be done annually to determine whether anything accumulative was degrading the fish. She also asked Mr. Snyder if there were any plans to test fish. Mr. Snyder replied that at this time there was not a fish study planned. Ms. Caffyn asked why there was not a study planned. Mr. Snyder replied that reason why there was not a study planned was because no accumulative damage had been detected in and past and because there was no change to the conditions, there was no need to test at this time. Ms. Caffyn stated that there were tumors found on many fish in the 1994 test. She also stated that there were indications that the fish were degraded by something and felt that that would indicate that the pond be monitored and have annual testing. She went on to say that she did not understand the aspect of not testing the fish because the fish tied directly in to the health issue. She also said that at a previous meeting, an audience member said that there had been at least six miscarriages in the area along West fence 1. Ms. Caffyn also said that the residences would like to be reassured every year that the pond and the fish were healthy. Mr. Snyder said that thesurface water and sediment were tested and that there no VOC’s were found. He went on to say that typically, if the surface water was free of VOC’s, the fish would be also. He also said that there were incidences across the region of tumors on fish. Ms. Theriault, a resident of Briarwood, asked whether any of SD-5 went under the Pond. Mr. Snyder referred back to the fate of contaminant slide and said that the bulk of the plume was going under Johns Pond but whether it would stay in the groundwater was not known. Mr. Dow said that the plume obviously entered Johns Pond at a certain point, he asked what kind of area the plume emanated from and what kind of concentration was in that area. Mr. Snyder said that microwells were installed on the shore line where the upwelling had occurred. He said that sampling had been done at various depths and that the plume was not detected in the pond itself, just in the ground. Mr. Dow then asked if the plume acted as a spring in the detected locations. Mr. Snyder replied that based on the study, the contaminants were just below ground surface area and that yes, there was a recharge. Mr. Dow asked how close the spring area was to where people either swam or fished. Mr. Snyder stated thatit was near the boat ramp. Mr. Dow asked how close to shore was this area. Mr. Snyder stated that it was not right at the shore line. Mr. Sobel said maybe 20 to 30 feet below the surface and maybe 20 feet offshore. Mr. Snyder said that it was difficult to determine exactly and that discharge was occurring at an area approximately 20 feet below surface. Mr. Perry said that it was about 15 feet below the pond bottom and that as the study examined deeper locations, the detection was higher. He also said that the plume had not been detected in shallow water or in the sediment. He went on to say that there were areas of recharge but that actual springs had not been detected. Mr. Minior said that in agreement with Mr. Perry, there was not a not single point sources or springs that were upwelling in certain areas. He also said that that it was very diverse, almost like a sponge with a general seepage pattern along the whole side of the pond. He went on to say that the plume was not a river flowing in, it was more like an ocean spread wide and that there was not a single source. Mr. Pinaud asked Mr. Snyder to refer to the slide on percentage of mass and asked him to explain how three percent of the mass entered Quashnet River. Mr. Snyder stated that the three percent was part of what was going under the pond. Mr. Pinaud said that it did not travel through the pond it actually underflowed and popped up Quashnet River. Mr. Goydas of Jacobs Engineering clarified and said that a conservative approach had been assumed in tracking particles . He went on to say that three percent did make it into the Quashnet River and that a small portion of that discharged in to Johns Pond. He also said that 16 percent underflowed the pond and did not discharge into Johns Pond. An audience member asked whether the model dealt with Childs River which was located between both the Ashumet River and the Quashnet River. Mr. Goydas said that yes,25 plus ponds and streams were being looked at and it was concluded that the SD-5 South plume did not migrate toward the Childs River. Ms. Walker asked whether a transparency of the matrix was available. Mr. Snyder said that he did not have that transparency available. Ms. Walker asked Mr. Snyder to discuss the strengthens and weaknesses of the alternatives. She also said that she noticed that the volume of total capture by each active system were similar in effectiveness. Mr. Snyder stated that all of the alternatives satisfied the ecological threshold and that 60 to 75 percent of capture would occur. Mr. Sobel asked if he was referring to the decision criteria document. Mr. Snyder replied yes he was. He also stated that the real pros and cons for the SD-5 alternative would come down to construction issues. Mr.Pinaud asked what kind of construction would be occurring in the neighborhoods. Mr. Snyder replied that each alternative would require a series of extraction wells along the roadway. He then said that the construction would be done on the right of way with as little interruption as possible and that the use of private property was a last resort. He went on to say that drill rigs and other equipment would be used and that the number of equpment being used at one time would reflect what the particular areacould handle. Mr. Snyder also said that the wells would be connected with subsurface pipes and control wires. He stated that remote controls were used to control the speed of the pumping and to monitor the effectiveness of the pumps. He also said thatthe treatment plant would more than likely be located on base property and that pipeline would be needed to connect the wells to the treatment plant. He mentioned that within the ditch used for the connecting pipes, there were also pipes that contained the clean water being sent to the reinjection wells. Mr. Snyder said that the recirculating wells would have a 30’ x 30’ concrete vault located subsurface with a manhole access and that there would be some construction on the road in order to get equipment into the vault. He also said that the use of residential property was required. An audience member asked whether there would be any sound or odor that would come from the wells. Mr. Snyder replied that the extraction wells had submersible pumps and therefore there would not be any sound. He also said that the recirculating wells had blowers or pumps but that they were located in the subsurface vault so any sound would be inaudible. Mr. Sobel asked whether it was possible for people to visit the existing SD-5 North facility. Mr. Snyder said that it was not because it was located in an area where there were safety and health concerns. He said that an open house was occasionally held and that the public was welcome to attend. Mr. Sobel said that anyone interested in attending an open house should follow up with Mr. Whitaker. Mr. Pinaud asked about the 16 percent of the plume that underflowed Johns Pond. He said that the municipal Mashpee wells on the other side of the pond pulled water in from an area that reached up through Johns Pond. He asked what the effect would be on Mashpee’s water supply if "no action" was selected. Mr. Goydas said that if no action was taken on the plume and it’s contaminants, it would trigger a whole new evaluation process to predict what the concentrations might be. He also said that that particular assessment had not been conducted to support that consideration but that several rough estimates of concentration have been studied. Ms. Caffyn asked how far SD-5 South reached beyond Johns Pond. Mr. Snyder replied that that would be determined in the next part of the investigation. Mr. Sobel stated that the public comment period ended on November 21, 1997 and the decision would be announced on December 15, 1997. Mr. Sobel then thanked everyone for attending and adjourned the meeting at 7:23 P.M.
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