Town of Sandwich
Selectman Hardwick called the meeting to order at 7:00 P.M. and stated they would attend to other business as the Plume Containment Update portion of the agenda is not scheduled until 7:30 P.M. Opening Remarks: Doug Karson At 7:30 P.M. Selectman Diane Tucker introduced Doug Karson of the IRP Office who then presented his opening remarks. Mr. Karson thanked the Selectmen for the opportunity to present the information on the plume containment process. He stated that he will give a brief overview and then Patti Tyler and Ernest Waterman of the US EPA will give detailed presentations. Mr. Ray Cottengaim of the US Army Corp. of Engineers, Real Estate Division is also present this evening and will available to answer questions regarding property issues. Mr. Karson showed overheads which outlined the timeline of the plume containment project. He noted that in 1994 the DoD committed the funds to being the design process. In Sept. 1995 the DOD/EPA/MassDEP agreed on a plan and in January 1996, the 60% design plan was released. In February 1996 public comment began on the 60% design and in March, new teams were established to review the design and make recommendations on the key design issues. The key design issues are to evaluate “hot spot” treatment, assess leak detection for piping systems, select location of extraction wells and determine return systems for cleaned water and agree on a level of treatment. The key design issues to be reviewed are to minimize impacts to ponds, streams and bogs; assess risks to public and environment of letting parts of plumes go; monitor operation and effectiveness of proposed systems; examine impacts to existing and future water supplies. The new teams established are the: Hydrological/Water Resources Group, Human Health/Ecological Group, Science Advisory Panel, Joint Teams (Plume Containment, Program Implementation and Long-Range Water Supply), Peer Review Team and Community Outreach Group. Mr. Karson also commented that future meetings scheduled are April 29, 1996 5:15 P.M. Joint Team Meeting at the Arnold Dining Hall, Otis ANG Base, April 30, 1996 7 P.M. Town of Mashpee Selectmen, Mashpee Middle School and May 1, 1996 7:00 P.M. Senior Management Board at the Arnold Dining Hall, Otis ANG Base. Ecological Technical Team Update, Patti Tyler: Ms. Patti Tyler of the US EPA then presented the update on behalf of the Ecological Technical Team. She also gave a handout entitled “ Ecological Technical Team Preliminary Report, April 25, 1996”. Ms. Tyler explained there are three sub-groups within the Eco Team, they are the eco risk group, the human health group and the eco impacts group. She then gave a brief synopsis of the eco and human health risks that may be associated with exposure to contaminants from the FS-12 plume. Some of the elements and questions of risk assessment are the Exposure Assessment: who/what is being exposed and how? Toxicity Assessment: at what levels does the contaminant cause an effect an what are the effects? Risk Characterization: what do we know about the risk and what are we uncertain about? In terms of looking at exposure assessment they evaluate the potential for human health risk from being exposed to contaminants in the groundwater and ecological risks are primarily aquatic organisms such as fish, shellfish, birds or mammals who eat the fish in pond that may be receiving discharge from groundwater plumes. In order for exposure to occur, an complete exposure pathway must be present. There must be a source or mechanism of release which in the case of FS-12 is the fuel spill, the transport of retention media which is the ground or drinking water, the exposure point which is human ingestion, the exposure route and the receptor who is the human. Humans can be exposed through residential use of groundwater and through the use of surface water bodies for recreational swimming. Ecological receptors are exposed either directly to surface waters that receive groundwater discharge or through the consumption of prey that have been exposed directly. In evaluating the human health risk they looked at if someone were to install a drinking water well in the plume and if they were to ingest the maximum concentrations of contaminants for 350 days a year for 30 years. They also looked at surface water bodies for recreational swimming which takes into account a person swimming in Snake Pond, being exposed to the maximum concentrations of contaminants and swimming in that pond for 7 days a year for 30 years. Ms. Tyler stressed that these exposures are the worse case scenarios and are conservative assumptions so they can be confident when they say there is not a potential risk for either exposure. In evaluating the ecological risk, Ms. Tyler reiterated that FS-12 is NOT discharging into Snake Pond so this is a predictive risk assessment for both human health and ecological risk. They looked at the fish swimming in Snake Pond and what would happen if they were exposed to contaminants that discharges into the plume and then the osprey if they were only getting their food from Snake Pond. The bottom line for human health risk in all cases is the risk from residential use of groundwater that is above the US EPA target risk range of 1 in 10,000 to 1 in 1,000,000 of developing cancer due to a lifetime exposure of a substance. Ms. Tyler stressed at this point that at FS-12, the risk is significantly above the US EPA target risk range by an order of magnitude. This is a significant risk with respect to if you were to ingest the maximum concentrations of contaminants in FS-12 where ehtylene dibromide (EDB) is driving this risk. For all surface water bodies, risks to swimmer are below US EPA target risk range, except for those surface water bodies that could receive discharge from FS-12 and that is again a prediction of if that plume were to discharge into Snake Pond. There is uncertainty as to if the inorganics are moving in the plume and if they are available to the organisms that would be exposed to them. The presentation was then opened to questions: Selectman Alesse asked if there had been any studies with respect to an expectant mother swimming in Snake Pond and an exposure to EDB? Ms. Tyler responded she is not a human health specialist, she is standing in for Susan Stines and will bring the question to her. Hydrological Team Updates, Ernest Waterman: Mr. Waterman stated he is a geologist with the US EPA and has worked as a project manager and has experience with the Army Corps of Engineers in wetlands work. He is on the technical group for review and evaluation and also providing support on the Science Advisory Panel. He reviewed the 60% design plan and why it went off line a little in terms of being implemented at this time. He stated that when they came up with a design system to address the plume and achieve full containment, they ran into some significant surface water impacts. They saw up to three feet of drawdown in Snake and Ashumet Pond, so to compensate for that you would need direct discharge and that volume of water could disrupt the chemistry to the pond and cause impacts. It could also decrease the flow in some rivers. There would have been ecological impacts with wetlands, vernal pools, streams and estuaries so they needed to balance the conflicting goals within the Interim Record of Decision (IROD). That then forced the hydro team to evaluate what could be done on a plume by plume basis. For FS-12, the review team focused on an immediate design scheduled for 5/1/96 and a phased installed of a plume containment system. The group felt that FS-12 could go forward immediately. The FS-12 plume is near the groundwater mound, it has elevated contaminant levels, the plume and a portion of the aquifer are well defined and it is isolated from other contaminants at the MMR. The design constraints to be designed are to avoid an unacceptable drawdown of Snake Pond, avoid unacceptable change in water quality in Snake Pond, avoid unacceptable affects on J. Braden Thompson plume and achieve capture. They recommend to design, install and implement pump and treat system in a phased fashion which will allow optimization of the containment system. Mr. Waterman also summarized how they would address the hydrological impacts which is to come up with a very robust monitoring plan. They will also focus on potential ecological effects and have a three phased approach. The first phase is baseline information collection, then a more intensive sampling phase during the implementation of the containment system, and finally to establish a time table based on species life and an engineering design. Public Questions: Dick Loring of East Sandwich, member of the Sandwich Board of Health asked if the final result of the worse possible scenario of contamination was 1 in 10,000 which is below EPA standards? Ms. Tyler responded no, in terms of evaluating the potential risk to humans if they were to drink the maximum amounts of contaminated groundwater for 350 days a year for 30 years based on the contaminants in FS-12, there is a significant increase in risk, and it is well below EPA’s risk range which is 1 in 10,000 to 1 in a 1,000,000 in the risk range. You would have a greater increase of coming into contact with cancer if exposed to EDB during a lifetime. Mr. Waterman interjected that no one is
drawing groundwater from FS-12. Jim Martin of Sandwich asked about a letter he received on real estate values and also asked if they impact Snake Pond would they also impact all the previous wells in the area? Mr. Waterman responded that one of the design objectives is to protect Snake Pond from the west of the plume and to not impact the J. Braden Thompson plume to the southeast which means they have to pretty much leave the groundwater table where it is. Most of design schemes now involve containment fences at the toe and axial well running up the center to tilt everything towards the containment fence and then lines of reinjection wells on either side so you only see changes in the water table within the imprint of the plume. Mr. Martin then asked how they would determine use of the property? Mr. Cottengaim replied that value would be use for implementation of the system and that would be determined through an appraisal. Ms. Jean Sutton asked if extraction or reinjection wells will be installed in front lawns and if there would be a lot of trucks and people around? Mr. Waterman responded no, they are trying to avoid private property and prefer right-of ways and in terms of trucks, it will be hooked to a piping system so once it is up and running there would only be people coming by for maintenance checks. Ms. Susan Lagasse of Snake Pond Road asked if there are any poisons in the pond now? Ms. Tyler replied that FS-12 is not discharging into Snake Pond. The Barnstable County Dept. of Public Health has been collecting and analyzing samples from the pond . The last sampling was Oct. 1995 and it was non detect, actual concentration of EDB was below the reporting detection limit of .02 micrograms per liter. Mr. Waterman also stated that the plume is moving past and side-swiping Snake Pond. Pam Hitchins, a reporter for the Sandwich Broadsider stated that last year the Sandwich Water District determined that the plume was discharging into Snake Pond, has that changed or do they disagree with their engineers? Mr. Waterman stated he has only been involved in the last couple of months and couldn’t respond. Mr. Marty Aker from the IRP Program stated they just completed a data gap program at Snake Pond where they installed a number of wells and some of the wells were adjacent to the shore of Snake Pond and they sampled the wells and it was determined there was no contamination going into Snake Pond. Ms. Hitchins asked if the District agreed with
that determination? Joel Feigenbaum, member of the PCT and PRT, stated the plan is still being designed. He also stated that EDB is the most dangerous substance on the Upper Cape and is in the center of this plume. Dr. Feigenbaum stated that the plume was discovered when the Sandwich Water District was looking for a well. In 1994 the Guard assumed responsibility for the plume. He wants assurance that the plume will not impact the pond and he wants an agreement to get extraction wells down the middle of the plume where the highest concentrations are. Mr. Feigenbaum also stated that the Water Dept. spent $350,000 to evaluate the plume and shut down Weeks Pond well which cost the Town over one million dollars. He is upset that there is still no compensation to the Town. Mr. Karson responded that Mr. Minior informed him that they have reached an agreement with the Sandwich Water District and $325,000 is forthcoming and the agreement will be executed in the next couple of weeks. Also, the Weeks Pond well is being currently being discussed for reimbursement. There was a question from the audience on how
close is FS-12 to the J. Braden Thompson plume. Brian Sutton asked if the cleanups of FS-12 and the J. Braden Thompson would be simultaneous? Mr. Waterman stated he is not sure of the J. Braden Thompson as it is not under the National Guard Bureau, but that is why they are designing so not to impact other plumes. Selectman Jan Teehan asked about the time it will take to establish a system to remediate the FS-12 plume vs. the time it would take for the plume to reach Snake Pond. Mr. Waterman replied there is no way to
accelerate the clean up. Mr. Karson stated that was a time line in the
60% design and once the contract is awarded, which Mr. Waterman stated that based on the information, they think the plume began in the forties and is not moving very fast. Mr. Marchessault of the US EPA commented that by May 15, 1996 the National Guard has to present a schedule to them which will be reviewed and put out for public comment for forty-five days being finalized by July 15, 1996. That schedule is an enforceable schedule. Mr. Waterman stated that even with phasing the implementation system, it shouldn’t add much time to the schedule, maybe a month or two. Selectman Hardwick thanked everyone for coming and thinks they are doing the best they can.
|
