Action Items:

1. Mr. Schlesinger asked to be provided with a Central Impact Area cross-section figure similar to cross-section D-D', but more toward the center of the plume.
2. Mr. Schlesinger asked to be provided with a figure that shows extended particle tracks from J-1 Range drive-points along the base boundary.
3. Mr. Schlesinger requested that the IAGWSP look into better ways to present data from monitoring wells.
4. Ms. Grillo indicated that Mrs. Moretti requested a letter clarifying what had been communicated to her regarding the results of the drive-point sampling that had occurred on her property.

Future Agenda Items:

• Natural Resources Discussion
• Massachusetts Department of Public Health Update
• TOSC Presentation on Dilution and Dispersion

Handouts Distributed at Meeting:

1. Responses to Action Items from the My 24, 2005 IART Meeting
2. Presentation handout: Remediation & Investigation Update
3. Maps/Figures to accompany Remediation & Investigation Update
4. Presentation handout: Fate-and-Transport Overview & Update
5. UXO Discoveries/Dispositions Since Last IART (Ending 7/19/05)
6. News Releases, Neighborhood Notices and Media Coverage 5/25/05 - 7/22/05

Agenda Item #1. Welcome, Agenda Review, Approval of Nay 25, 2005 IART Minutes

Mr. Murphy convened the meeting at 6:05 p.m. and reviewed the agenda. The Impact Area Review Team (IART) members introduced themselves and Mr. Murphy asked if there were any changes or additions to the May 25, 2005 IART meeting minutes. No comments were offered and the minutes were approved as written.

Agenda Item #2. Responses to Action Items and Late-Breaking News

Mr. Schlesinger referred to the response to Action Item #5, regarding the 4 part per billion (ppb) perchlorate detection at monitoring well 127 (MW-127), which now tests nondetect, and asked if there's a plan to investigate that contamination. Mr. Gregson explained that the 4-ppb detection was a "J" value, which was determined using the old analytical method for which the detection limit was about 4 ppb. He said that because the detection wasn't repeated in subsequent analyses using the lower detection limit, it's believed that that detection wasn't real in the first place.

Mr. Murphy announced that Michael Butler and Evelyn Hayes informed him that they are resigning from the IART. Ms. Grillo noted that she worked with Mr. Murphy to put notices regarding IART membership recruitment on the local cable television stations in Bourne, Mashpee, Falmouth, and Sandwich. Mr. Murphy added that over the next week or so he will be spending time in some of the neighborhoods along the southeast part of the base to hand out flyers about the meetings and try to develop some interest in IART membership.

Mr. Schlesinger asked why the news release about the recent RDX finding in Sandwich isn't being reported as a late-breaking news item. Mr. Gregson replied that he would be providing detailed information on this subject as part of the Investigation Update.

Agenda Item #3. Investigation & Remediation Update

Central Impact Area

Mr. Gregson stated that in response to a request made at the last IART meeting, he'll be showing three cross-section figures (one along the southern edge, one along the northern edge, and one at the toe of the plume) to illustrate that the Central Impact Area plume is really a composite of a number of areas of RDX and perchlorate contamination with different sources and different times of release.

Mr. Gregson displayed the southern cross-section (A-A') and pointed out how the distinct areas of contamination shown in the figure would appear to overlap in a plan view depiction. He then displayed the northern cross-section (D-D'), which he described as "more dramatic" in the way it shows different areas with different sources separated by clean groundwater. He also displayed the transverse cross-section at the toe of the plume (G-G') and noted that the areas of contamination are relatively deep in the section because they have migrated downgradient.

Mr. Schlesinger observed that the two-dimensional plan view makes it "look like a much bigger job" than the cross-sections do. Mr. Gregson explained that if the areas of contamination are followed up to the surface "they're all going to coalesce," and for ease of representation in a picture, the plan view encompasses a large area of detections, understanding that there might be clean spots in between. Mr. Schlesinger inquired about the clean space between MW-51 and MW-208 in cross-section D-D'. Mr. Gonser noted that the area to which Mr. Schlesinger is referring happens to be actually outside the plume, as can be seen in the plan view depiction.

Mr. Schlesinger suggested that if D-D' had happened to run right through that plume finger, it would be depicted as continuous in plan view. Mr. Gregson confirmed that it would, and added that the nature of the plume, being made up of separate areas of contamination, will be considered when looking at cleanup options. That is, it might make sense to use larger wells with larger extraction rates to capture everything from upgradient, rather than installing individual wells that target specific areas of contamination. Mr. Schlesinger said that he'd like to see a cross-section that runs more through the center of the plume and includes the higher concentration areas, including the one around MW-207. Mr. Gregson replied that he believes that such a cross-section exists and he could provide that to the team.

Mr. Dow noted that when looking at the cross-section figures he observed that the areas of contamination that are connected to their source areas at the surface are quite variable in length, which makes him think that the prevailing hypothesis that longer plumes represent older source areas might not actually be true. He also mentioned plumes at the edge of or outside of the base, such as the one at the Northwest Corner, and said that he wonders about the possibility of backtracking from those plumes to identify source areas and implementing a joint strategy of cleaning up the source areas as well as treating the groundwater. Mr. Gregson replied that there may very well be such cases, and so both soil and groundwater need to be considered. He also noted that the Northwest Corner plume is relatively deep at the base boundary and the current investigation is moving backwards from there to determine whether it might be connected to the Central Impact Area. He also said that it's possible that that plume is detached or that the source area that created it has become depleted.

Mr. Dow then questioned whether the source areas at the Central Impact Area are discrete enough that augmented biological treatment of them would be feasible. Mr. Gregson said that this leads him to the response to Mr. Cambareri's request at the last IART meeting for a map that shows the shallow areas of contamination overlaying the total plume. He explained that an effort was made to identify contaminant detections at the water table that would indicate an ongoing source in the soil above, where a remedial action might be conducted. He displayed the map depicting those areas of shallow groundwater contamination, including the area at the intersection of Tank Alley and Turpentine Road, another area based on a detection in one well, and Chemical Spill 19 (CS-19), a plume and source area that's being addressed by the Air Force Center for Environmental Excellence (AFCEE). Mr. Gregson overlaid the map depicting the areas of shallow contamination with the full Central Impact Area plume map, circled the shallow contamination areas, and said that an effort is being made to further fine-tune the depiction and identify source areas where bioremediation or soil removal actions can be conducted.

Mr. Cambareri said that it's interesting that the circled areas are currently receiving dissolved contaminant from source areas. And it's also interesting to look at groundwater contamination "at what you might think is a source area, but which is actually deeper," such as the area north of the two eastern circled areas, where one would think there'd be a source area, and perhaps there was at one time, but there's no water table contamination. He then asked if this means that that's an older source. Mr. Gregson replied that it's a very complicated picture, but cratering in that area indicates that "this was a part of the base that was shot at earlier than areas down here, so it may be an older source that's causing that feature." Mr. Cambareri then asked, "So you don't think it's detached from anywhere else upgradient in order for it to get that low?" Mr. Gregson replied that "they may have shot something in here, but this just moved slightly downgradient."

Mr. Cambareri then inquired about the area of contamination to the east. Mr. Gregson replied that it is the J-1 Range plume. Mr. Cambareri asked if the J-1 Range plume is on the same trajectory "as that northern part that we were just looking at." Mr. Gregson replied that he thinks it would go east of that.

Mr. Schlesinger noted that MW-103, MW-123, and MW-124 along transect G-G' are all nondetect, and he questioned why the groundwater in that area seems to move north and then "turn there," as opposed to "groundwater flow according to these gradients." Mr. Gregson mentioned the multiple source areas and suggested that that portion of the plume has migrated farther in that direction and would track back "someplace probably in here." Mr. Schlesinger said that he understands that, but wonders "why aren't we then finding something back in here." Mr. Gregson replied that thinking of the Central Impact Area plume as a traditional plume makes things complicated, because it is not a traditional plume. Rather, it's made up of a composite of multiple plumes. He added, "In general, contaminants that are found in this area entered the groundwater and flowed in this direction. So we're seeing a few detections here, that detection out here, and that's what this is based on."

J-2 Range Soil RRA

Mr. Gregson reported that the J-2 Range Soil Rapid Response Action (RRA) is in its final stages. Since the last time the team was updated, soil and anomaly removal was conducted at three grids in the Twin Berm area, four grids in the area of Berm 5, and eight grids at Polygon 2. He noted that more than 35,000 metal items have been investigated and removed, 1,820 of which were munitions or munitions-related items. Additional soil removal is planned at Polygon 2, and that soil will be shipped off site to a licensed facility.

J-2 Range Soil Investigations

Mr. Gregson noted that additional soil investigation at the J-2 Range is being conducted in order to identify other source areas of groundwater contamination. To date, eight grids have been investigated, and a total of 340 tons of soil and three tons of metal debris have been excavated, which included 159 munitions or munitions-related items. The work is expected to continue through early next year, and once completed it will be determined whether any additional RRAs or remedial actions need to be done.

Mr. Gregson also mentioned that similar work is being conducted at the J-1 Range, where 50 grids, which are prioritized based on the strength of the signal and their location on the range, will be investigated. He noted that some of the grids near the potential source area for the high concentration of RDX that was recently detected will be investigated first. He also said that 17 total grids on the J-1 Range are scheduled to be completed this year.

Mr. Walsh-Rogalski asked if information about the unexploded ordnance (UXO) items being found is logged somewhere, and whether the U.S. Environmental Protection Agency (EPA) receives that information. Mr. Gregson replied that the items are identified and photographed, and the information is logged. He also said that EPA is on the distribution list for that information, which is sent out via e-mail under the heading of the particular grid.

Mr. Schlesinger said that the list of UXO discoveries awaiting the contained detonation chamber (CDC) doesn't include the grid associated with each item, which he would find helpful. Mr. Gregson noted that the monthly reports contain a cumulative listing that breaks down by grid which items were found at which location.

J-2 East Recent Results

Mr. Gregson showed a map of the J-2 East area and reported that MW-381 was drilled in order to try to delineate between the J-2 North plume and the J-2 East plumes, MW-372 was drilled as a downgradient well to try to identify the toe of the central J-2 East plume, drive point 371 (DP-371) was drilled to see if the detections in MW-319 are connected to the central J-2 East plume, and DP-377 was drilled to see if any J-2 Range contamination is heading off the base boundary south of the southernmost J-2 East plume. Mr. Gregson also pointed out on the map the locations of the Forestdale School, a cleared area where a bird-bath store used to be, a garden center, and the intersection of Quaker Meeting House Road and Route 130.

Mr. Gregson reported that each of the four wells was nondetect for RDX. Perchlorate was detected in MW-381 at 0.45 ppb at 82 to 92 feet below the water table (bwt). Two screens were set in that well: one to correspond with the detection and a deeper one to correspond with particle tracks from the upgradient well. A water table piezometer well was also installed at that location in order to monitor water levels in the vicinity of the injection trench for the proposed J-2 North plume groundwater treatment system. MW-372 was nondetect for perchlorate, which helps define the toe of the central J-2 East plume. DP-371 had perchlorate detections in a couple of intervals, up to 2.1 ppb, which indicates that the southern J-2 East plume may be "a little larger and a little more to the north" at that location. DP-377 was nondetect for perchlorate.

Mr. Gregson also discussed the J-2 East investigation in the Forestdale area of Sandwich. He noted that an existing AFCEE well, 90MWT0014, which is screened near the water table, was sampled and it tested nondetect for perchlorate and explosives. He also said that about eight to ten drive-points have been drilled to help guide the investigation, including one on the private property at 3 Peters Pond Drive (DP-382). Perchlorate was detected in one of nine intervals sampled, at 1.5 ppb, at 9.5 to 14.5 feet bwt, and these findings are consistent with the concept that there is a likely source nearby the contamination at 3 Peters Pond Drive. Mr. Gregson then turned to Mr. Olson of EPA to discuss further investigation in that area.

Mr. Olson stated that right now EPA's opinion is that the perchlorate contamination at Peters Pond Drive is not currently coming from the base, but the question remains whether there is a local source, and if so, what that source is. The possibilities "could be anything," including historic military activities that occurred off base (evidence of which can be seen in aerial photographs), and fireworks. Mr. Olson noted that for now EPA is taking over the investigation and will be working with the U.S. Geological Survey (USGS) to collect piezometric data in the Peters Pond area in order to determine whether the macro-scale models that have been used actually fit on the micro-scale "of this small area," whether the groundwater direction is as predicted, and whether there's any upward flow in the groundwater there. Once the additional piezometric data have been collected, the models that have been used thus far can be adjusted to see if there appears to be a likely source nearby, which may or may not be someplace different than what the Impact Area Groundwater Study Program (IAGWSP) is currently predicting. Once that is known, a decision will be made as to whether or not to chase the source, if it's possible actually to find the source.

Mr. Olson added that a bigger question is whether there are higher concentrations of perchlorate upgradient that would eventually move toward the Peters Pond area, or whether the worst slug of contamination already has been discovered and levels are going to start to decrease. He noted that concentrations in the well where perchlorate had been detected above 1 ppb had decreased in the last round of sampling; however, that was only one round and more sampling will be done. He also referred to the other wells on Peters Pond Drive that had shown low perchlorate levels using EPA's lower detection limit method, and noted that in the last round of sampling they were nondetect for perchlorate, again using EPA's method.

Mr. Olson reiterated that the plan is to gather some piezometric data fairly quickly and determine what needs to be done next. He also said that he realizes that the residents on Peters Pond Drive probably aren't looking to hear the EPA is taking over to do more studies, as everyone would like to just get those homes hooked up to public water. However, "we frankly haven't been able to figure out a way to legally do that at this point and pay for it." Mr. Olson also noted that the perchlorate levels at Peters Pond Drive are "almost by anyone's calculation" very low.

Mr. Schlesinger asked if the information gathered from 90MWT0014 was at the appropriate depth to corroborate the drive-point finding at Peters Pond Drive. Mr. Gregson replied that what's being seen at DP-382 may be under-flowing that particular location. However, as Mr. Olson explained, EPA is going to get some additional information to see if the groundwater model there is accurate. Mr. Schlesinger then asked if EPA's additional work will entail some kind of deeper sampling method to determine if there's perchlorate at the depth that the drive-point showed. Mr. Olson replied that the idea behind collecting the piezometric data is to try to determine whether the particle track is "actually going in the direction that it shows there." Once the accuracy of the particle track is established, EPA may want to install an upgradient drive-point "right at the right depth, right at the right location" to determine whether perchlorate levels there, if they exist, are higher. He noted that he doesn't think there's adequate characterization at this point to make that determination.

Mr. Schlesinger then inquired about the possibility that the perchlorate at Peters Pond Drive might be the result of historic military activity. Mr. Olson clarified that EPA is of the opinion that the contamination is too shallow to be coming from the base, but believes that it's possible that historic activities that occurred outside the base boundary could be the source. If the perchlorate levels continue to be as low as they've been, however, it probably won't be possible to find the source area. Mr. Olson added that he thinks the work needs to be done in a step-by-step process.

Mr. Schlesinger asked if there's a plan to install monitoring wells in the area of the road that runs approximately northwest from MW-362. Mr. Gregson replied that a number of conventional monitoring wells have been installed upgradient of Peters Pond Drive, including one across from the garden center, one on the school driveway, and several others, all of which were drilled through the entire aquifer and tested nondetect for perchlorate and explosives. He also said that as he understands it, the focus of EPA's investigation will be to fine-tune the hydrogeologic interpretation in the Peters Pond neighborhood to see if a closer source can be identified. Mr. Schlesinger suggested that the width of the plume "could very easily come down right between" the existing upgradient monitoring wells. Mr. Gregson replied that "some tricky hydrogeology" would be required for that to happen, and although he'd never say that anything's impossible, the data do not indicate that. Mr. Olson added that even if the plume were traveling in that direction, it would be likely to be deep in the downgradient location.

Ms. Conron asked Mr. Olson to describe EPA's investigation plan again. Mr. Olson stated that EPA is taking over the investigation at this point because it seems as likely as not that the perchlorate isn't from a military source. He said that EPA will be working with USGS, as well as the Massachusetts Department of Environmental Protection (DEP) and the IAGWSP, to determine which way the groundwater is flowing in the immediate vicinity of the perchlorate detections in the Peters Pond neighborhood. Also, to see if there are vertical gradients there that would indicate that the groundwater gets deep and then suddenly comes back up as it gets closer to Peters Pond, which is possible although unlikely given the distance from the pond. Once this information has been gathered, the plan is to adjust the models accordingly and figure out in which direction the source might be. If there's a chance of finding the source, an effort will be made to do so, or at least to locate an upgradient point and determine whether or not there are higher perchlorate concentrations there that could potentially move toward the wells in the Peters Pond neighborhood.

Ms. Conron inquired about the timeline for the investigation. Mr. Olson replied that the plan is to move as quickly as possible, and EPA is working with USGS to work out the specifics. He also said that he's certain that everyone understands that time is of the essence in this situation, and so it's a top priority for EPA, which has the funding in place to do investigation.

The homeowner at 3 Peters Pond Drive said that she's a little confused tonight because two weeks ago Dave Hill of the IAGWSP telephoned her to say that test results from the drive-point installed on her property indicate that the perchlorate is not coming from the base, but it could be from fertilizer used at the greenhouse on Route 130. She said that she had asked him if she should now turn to the state, the town, or the health department. She said that Mr. Hill had replied that she should turn to all of the above, as the IAGWSP was washing its hands of the investigation and would no longer be testing her water. She also noted that in response to some of her questions, Mr. Hill replied that his office had notified EPA, the health department, and State Rep. Jeff Perry. However, when she called EPA and Mr. Perry, she found that they hadn't been notified, and the health department told her that there was nothing it could at this time. She further noted that today, unexpectedly, the IAGWSP came to test her water, after she was told that it would no longer be doing so.

Mr. Olson said that EPA's understanding is that the IAGWSP is not going to stop testing the wells on Peters Pond Drive. Mr. Gregson noted that Mr. Hill's statement about the perchlorate coming from Route 130 is based on the particle track that points to a potential source area near the intersection of Route 130 and Quaker Meeting House Road. Mr. Gregson also said that some types of fertilizer can be a source of perchlorate. However, it's uncertain whether the groundwater flow is such that the perchlorate at Peters Pond Drive could be coming from the garden center on Route 130, and EPA will be looking at this possibility. He also referred to the sampling done at 3 Peters Pond Drive today and explained that he had directed the contractor to conduct an additional round of sampling so there wouldn't be a gap in information. Another round will be conducted in August, and samples from both rounds will be turned over to EPA for analysis.

The homeowner at 3 Peters Pond Drive inquired about the monitoring well across from one of the greenhouses on Route 130. Mr. Gregson noted that MW-362, near the northernmost garden center, had tested nondetect for perchlorate, as had the irrigation well at another garden center in the area. He noted again that the actual source is not known.

Mr. Gonser noted that if Mr. Hill had said that the IAGWSP is "washing its hands" of the investigation, that was incorrect. Rather, the IAGWSP will continue to work with EPA and DEP to come up with a resolution and bring whatever assets and advice to the table that it can, although EPA will be taking the lead in the investigation.

The homeowner at 3 Peters Pond Drive said that she thinks Mr. Walsh-Rogalski mentioned that the other residential wells on her street had only traces of perchlorate. Mr. Walsh-Rogalski clarified that his understanding is that in the last sampling round the other wells tested nondetect, using EPA's low detection limit method. He said that he thinks this is good news, but it was only one sampling round. He also referred to the off-base military activities that were mentioned and noted that he has some aerial photographs that show trails going off the ranges into the general area of Route 130. He then made the photographs available for the team members to see.

Mr. Cambareri urged EPA to expand the scope of its investigation to include the area downgradient of the detections on Peters Pond Drive, towards Peters Pond, given the possibility that the perchlorate that's been detected could be the tail end of a plume. He then said that he hopes that the drive-point rig is part of the resources that the IAGWSP continues to bring to the table as EPA conducts its investigation, and added that he believes that drive-points can be easily installed downgradient as the water table is shallower closer to Peters Pond. He also mentioned that he's concerned that there's talk about perchlorate being a component of fertilizer, yet no evidence has been presented to indicate that fertilizer is a potential source. Mr. Cambareri then suggested that perhaps the perchlorate contamination at Peters Pond Drive could be explained by a pump test or some type of irrigation activity that took water from deeper in the aquifer and discharged it into a shallow zone, and he mentioned the wells that were pumped for the Long Range Water Supply investigation associated with the Upper Cape Water Cooperative project. He also said that he's glad that the IAGWSP will continue to bring resources to the investigation and would love to see some resources go toward "alleviating the emotional pain and concern" of the affected residents.

Mr. Schlesinger asked if it was the IAGWSP office that spoke of the fertilizer issue to the homeowner at 3 Peters Pond Drive. Mr. Gregson confirmed that she had said that Mr. Hill of the IAGWSP had mentioned fertilizer as a potential source of perchlorate, which he (Mr. Gregson) understands to be accurate. Mr. Schlesinger then asked if it's possible to use the groundwater model to determine where the fertilizer would have to be in order to cross into the residential well at 3 Peters Pond Drive. Mr. Gregson explained that the additional work that EPA plans to do will ensure that the groundwater model in that area is accurate and will provide information to help find the source.

Mr. Schlesinger inquired about a similar approach being taken at the Northwest Corner, another location where perchlorate was detected near the water table. Mr. Gregson replied that the IAGWSP has already completed the bulk of the investigation at the Northwest Corner and is currently working on some air modeling to support a remedial investigation report. He also said that it does appear that the shallow perchlorate contamination at the Northwest Corner, like that at Peters Pond Drive, is the result of a local nearby source.

J-1 Drive-Point Update

Mr. Gregson updated the team on results from the drive-points that were installed along the base boundary and downgradient of the J-1 Range, a contractor test range that was used from the 1950s to the 1980s. He reported that DP-378 and DP-379 tested nondetect, but DP-384 had RDX detections in five intervals (from 26.4 to 80.4 feet bwt) at concentrations ranging from 5.1 ppb to 290 ppb. In response to the detections in DP-384, another drive-point (DP-386) was drilled to the north, which had RDX at similar depths (48 to 83 feet bwt), but at considerably lower concentrations, from 0.34 ppb to 6 ppb. Another drive-point, DP-387, was also drilled, but water didn't come into the point immediately. DP-387 has subsequently been inspected, however, and it now has water and a sample can be collected, which is expected to provide additional information on the width of the RDX plume in that area.

Mr. Gregson reported that the IAGWSP is currently drilling drive-points along Greenway Road. He also noted that two existing wells at the end of the J-1 Range were sampled and tested nondetect. The first of three drive-points has been drilled, and it had an RDX detection of about 12 ppb. The next drive-point will be drilled south of that location as part of the effort to define the core of the plume at the base boundary, fine-tune the model, and identify priority off-base drilling locations. Mr. Cambareri asked if it's correct that perchlorate has not been detected in this area. Mr. Gregson confirmed that it is.

Mr. Gregson reported that the IAGWSP has done a thorough survey of the downgradient private residences and has determined that all of them have town water hookups. A subsequent look at the area farther downgradient showed that about a mile away there may be a neighborhood of about 16 homes with private residential wells. Mr. Gregson noted that the IAGWSP is going to follow up to confirm this information. He also said that if it's possible to quickly obtain access to a drilling location that indicates whether the plume extends farther downgradient, the IAGWSP will do so. If access issues seem to be taking too much time to resolve, however, it's possible that a decision will be made to move right ahead with collecting samples from the residential wells identified about a mile downgradient.

Mr. Gregson stated that the IAGWSP has contacted the Sandwich selectmen and the Board of Health regarding these RDX detections, and is scheduled to be on the agenda at the August 11, 2005 selectmen's meeting to discuss drilling access in town-owned roads and town properties such as the fire station on Route 130. Also, the IAGWSP and the regulators will be getting together at the regularly-scheduled Thursday technical meeting to discuss specifics about off-base drilling locations between the base boundary and Route 130, and then move forward with gaining rights-of-entry for well installations. Mr. Gregson noted that the IAGWSP probably will continue to use drive-point technology closer to the base boundary, and then, because of depth, will likely find it necessary to drill conventional monitoring wells farther downgradient.

Mr. Panni asked to see particle tracks from the two locations where RDX was detected. Mr. Gregson displayed a map and pointed out the backward particle tracks from DP-384, DP-386, and the first drive-point on Greenway Road, where RDX was detected at 12 ppb. He also pointed out two nondetect wells and said that the source appears to be "something that's right on the edge of what was the firing point of this particular range."

Mr. Schlesinger questioned whether it would make sense to look for perchlorate farther downgradient, given that in many cases RDX plumes are co-located with perchlorate plumes, but the perchlorate tends to be out in front of the RDX. Mr. Gregson noted that the contamination associated with Demolition Area 2 is RDX only, but agreed that in most cases RDX and perchlorate both have been detected, although neither has been detached from its source area. He further noted that as the investigation moves downgradient, sampling for perchlorate will be conducted to ensure that there isn't a detached perchlorate plume out in front of the RDX. Mr. Schlesinger asked to be provided with a figure that shows extended particle tracks from the J-1 drive points along the base boundary, and Mr. Gregson agreed to do so.

Mr. Murphy asked if the neighborhood that's downgradient one mile is in Sandwich. Mr. Gregson replied that it is on the Sandwich/Mashpee border, but still in Sandwich.

Ms. Conron inquired about the yellow "hockey stick" on the map. Mr. Gregson explained that it represents a drilling swath, where clearance is done to ensure that no natural or cultural resources would be affected by drilling within that area. Mr. Gonser added that in the past the IAGWSP would consult on a well-by-well basis with the State Historic Preservation Office (SHPO) and the Tribal Preservation Office (TPO), which was a time-consuming process, but was able to negotiate a swath concept whereby the SHPO and the TPO give their permission (in a 30-day period) for the IAGWSP to drill in a number of locations, as long as they are within certain parameters.

Mr. Dow said that it seems to him that the contamination detected in the drive-points along the base boundary would be deeper, since they're downgradient of the detections along Greenway Road, but it's not apparent that that is the case. Mr. Gregson noted that because of the depth limitations of a drive-point, it hadn't been possible to reach a clean bottom to the plume at a drive-point along the base boundary. Therefore, the IAGWSP is proposing the installation of a conventional monitoring well there in order to gather groundwater data throughout the contaminated zone.

Mr. Dow then asked if the high-concentration contamination at the base boundary tracks back to a potential upgradient source that could produce "that large of an RDX plume." Mr. Gregson said that this is a good question, given that the RDX concentrations are similar to those seen at Demolition Area 1 (Demo 1), but the magnetic anomalies at the J-1 Range are nothing like those seen at Demo 1, which had a five-acre bright spot. He suggested that perhaps this is because the source is not munitions, but instead something such as wastewater containing RDX that was repeatedly dumped upgradient. Mr. Gregson said that the geophysical work that's been done so far hasn't shown a huge bright spot that would indicate a source area.

Mr. Pinaud noted that the source of some of the other J Range plumes is right at the top of the groundwater mound, and given that the J-3 Range plume (which has RDX concentrations of 10 to 20 ppb) is about 3,000 feet long, and assuming that the source of this J-1 Range plume is at the top of the mound and that the sources all started at the same time, it's possible that this J-1 Range plume, with its higher RDX concentrations, might extend to the other side of Route 130. Mr. Gregson agreed that it's possible that the plume could extend "quite a ways downgradient."

Mr. Pinaud then apologized for having missed part of the presentation and inquired about the schedule and scope of work for follow-on activities. Mr. Gregson replied that off-base drilling locations will be discussed at Thursday's technical meeting and a written workplan probably will be available in a couple of weeks. Also, the IAGWSP will continue the drive-point investigation and working the real estate access issues. Mr. Pinaud also inquired about residential wells in the area, and Mr. Gregson repeated the information about the downgradient neighborhoods. Mr. Pinaud then asked if the IAGWSP was able to contact the Mashpee Board of Health today. Mr. Gregson informed him that the IAGWSP had not contacted the Mashpee Board of Health because it turned out that the residential wells are not in Mashpee. However, his office did contact the Mashpee Water District to see if any of the wells were in the free zone boundary where the homes might be serviced by Mashpee even though they're located in Sandwich.

Mr. Walsh-Rogalski noted that he seems to recall that a couple of years ago the Textron people spoke of Hesse Eastern having some kind of shack to store perchlorate used in Minuteman missile testing. He said that he doesn't know if there was also a melt/pour facility or what other types of material may have been kept there, but recommended that the IAGWSP review that information as it might be helpful in identifying a source.

J-3 Range Recent Results

Mr. Gregson reported that MW-383 was drilled along the edge of the Impact Area in an effort to determine whether contamination was coming from the barrage rocket site located at the end of the J-3 Range. Perchlorate was detected in two intervals at MW-383, at relatively low concentrations of 0.36 ppb and 0.54 ppb. Two well screens were set and samples will be collected to see if the detections are repeated. Other nearby wells tested nondetect for perchlorate, but the IAGWSP will continue to investigate whether any contamination is coming off of that part of the J-3 Range.

Mr. Schlesinger referred to the map and inquired about a series of wells depicted in yellow (meaning greater than 0.35 ppb to less than 1 ppb detections), which are outside of any plume outline. Mr. Gregson replied that those detections may be connected to several small plumes associated with the L Range, which do not show up well on the figure. He also noted that the map shows "all detections that ever happened" some of which may have occurred only one time. Mr. Schlesinger asked that the IAGWSP look into better ways to present this "time series" of information, perhaps by splitting it up in such a way that it could be better understood what has happened over time. Mr. Gregson replied that this would be considered as the map issue as a whole is addressed. He also noted that plumes with more advanced investigations, such as the J-3 plume, have models that can be run to see what's occurred over time; however, in this case there's not yet enough information to develop that type of representation.

At this time, Ms. Grillo noted that the homeowner at 3 Peters Pond Drive had left the meeting, but had asked her to mention that during her telephone conversation with Mr. Hill, he had agreed to provide a letter clarifying what they had discussed. Ms. Grillo said that it has been two weeks since that conversation, and that letter has not yet been received. Ms. Grillo recommended that this issue be addressed as an action item.

Demolition Area 1 Recent Results

Mr. Nixon displayed a map of the Demo 1 plume and noted that he'd be discussing results from the Demo 1 RRA system April 2005 System Performance and Ecological Impact Monitoring (SPEIM) sampling round, which showed an increase in perchlorate concentrations at several of the wells at and downgradient of Pew Road. Generally the concentrations seem to be increased in the center of the plume and pretty much the same or lower elsewhere. A table included in the presentation handout showed the results that Mr. Nixon reviewed: MW-211 (at Pew Road) - perchlorate at 33 ppb in December 2004 and 25 ppb in April 2005; MW-341 (at Pew Road) - 15.5 ppb in December and 40 ppb in April; MW-225 (between Pew Road and the power line) - 3.2 ppb in December and 7.7 ppb in April; and MW-258 (at the power line) - 1.6 ppb in December and 4 ppb in April. Mr. Nixon stated that based on historical data, it seems that what's being detected in these wells are "a couple of pulses of contamination moving through the aquifer," given that these higher concentrations passed by the upgradient wells before they were installed. Also, data from the upgradient wells indicate that there are lower concentrations behind the current pulses of contamination. Mr. Nixon noted that this is of particular interest because the IAGWSP is in the process of trying to determine the best way to address the toe of the plume.

Mr. Nixon noted that sensitivity analyses were conducted to look at the difference between the five- and six-well systems. It was determined that adding the sixth well at the toe of the plume would reduce the remediation timeframe by a couple of years and prevent a couple hundred feet of plume migration, but would cost almost an additional $4 million. Mr. Nixon said that the remedy selection process for a final cleanup decision on the plume is ongoing, and while there's agreement about the five wells, the question remains as to whether the appropriate response at the toe of the plume is passive or active remediation.

Mr. Nixon stated that the new higher concentrations raise "at least a yellow flag." He said that the plan is to take a closer look, re-delineate the plume during the month of September, and issue a SPEIM report in October. He explained that the IAGWSP is going to look at the new concentrations and the hydraulic gradients in the area and try to determine appropriate contingency actions that put a trigger in place to go to a six-well system if it's found that passive remediation at the toe of the plume won't lead to an acceptable outcome. Mr. Nixon also said that the next sampling round is scheduled for August, and that the new modeling results should be available for discussion at the October IART meeting.

Mr. Panni asked if the plume concentration contours shown on the map reflect the new findings. Mr. Nixon replied that the contours shown on the map have not yet been updated. He also said that he doesn't think there'd been time to do that, and noted that although he understands the shortcoming of it, because of timing, new results typically are superimposed over old plume delineations.

Mr. Schlesinger inquired about the distance that the higher concentrations would reach by the time the final system is in installed. Mr. Nixon replied that the IAGWSP needs to work out the details of what would trigger a decision to build a sixth extraction well. He also said that as part of the contingency he thinks that the IAGWSP would at least complete a conceptual design so that it could be implemented rapidly. He also mentioned that it might involve using one of the container systems, which should be idle as of January 2007. Mr. Schlesinger then asked if there's a worst case and best case for placement of a sixth well. Mr. Nixon replied that there are a number of options, including permutations involving increased pumping rates and the installation of a well at the base boundary, although it's too early to pin one down.

Mr. Walsh-Rogalski asked what is meant by the term passive remediation. Mr. Nixon replied that this means remediation that relies on natural processes, such as dilution in this particular case. Mr. Walsh-Rogalski suggested that it really means doing nothing, and Mr. Nixon noted that another term is monitored natural attenuation (MNA).

Mr. Cambareri inquired about the influence of the downgradient pond on the toe of the plume. Mr. Nixon replied that the current model predicts that the pond (which is four feet deep) will have a small influence on the trajectory of the plume, "a small upward, and then on the down side of the pond, a small downward influence." He also said that the new modeling that's going to be conducted for October's SPEIM report will involve modeling with and without the influence of the pond to see whether the pond effect changes the ultimate movement and degradation of the plume. Mr. Cambareri said that based on the original model he hadn't thought the pond had enough influence to create a stagnation zone, as had been suggested. Mr. Nixon said that the animations show "a pretty good size cusp," and also mentioned the vertical exaggeration in the model, which makes it appear that the pond has a much bigger effect than it really does.

Mr. Dow asked why the northern part of the toe of the plume has advanced farther than the southern part. Mr. Nixon replied that this is probably due to fairly small differences in hydraulic conductivities. He also said that the new plume delineation and latest data that go into the new model might help account for that. Mr. Dow said that he's concerned about the areas of low hydraulic conductivity at the base boundary that might trap the contamination, and asked how long it would take on the current path before those zones are reached. Mr. Nixon referred to the map and pointed out the moraine and the outwash areas. He also pointed out two wells where no confining layers were found, only typical sand. Mr. Dow asked if there were any changes in the hydraulic conductivity in the moraine area. Mr. Nixon replied that there's huge change in the area just beneath the plume, which rides on a clay layer. However, by the time you get to "right around here" there is no more clay layer showing up in the wells. Mr. Dow concluded that the moraine must be farther east than he'd thought. Mr. Cambareri mentioned that the pump test for Long Range Water Supply well 10 showed a "fantastic yield" of water, and was being considered for use before it was realized that doing so might affect the nearby ponds.

Agenda Item #4. Fate & Transport Overview and Update

Mr. Murphy noted that he'd forgot to mention earlier that Bob Mullennix contacted him to say that he wouldn't be able to attend tonight's meeting.

Mr. Gregson stated that fate is what happens to a compound when it's in the environment and transport is how it moves through the soil and groundwater. He also mentioned that information contained in his presentation comes from the University of Texas (UT) laboratory study of the fate and transport of high explosives conducted several years ago, as well as from what's been learned through the cleanup program, and the data that have been collected through investigations. He noted that understanding the fate and transport of contaminants is an integral part of modeling and predicting how they'll move through the groundwater and what the risks are to downgradient receptors.

Mr. Gregson noted that explosives enter the environment from disposal activities, from low-order detonations when not all of the explosives are consumed, and from residue from munitions firing and detonation. The size of the particles can range from microscopic to chunks the size of a toaster; the smaller the particle, the more relative surface area there is, and the more quickly the particle dissolves. Precipitation (rain and snow) percolates over the contaminants and causes them to dissolve and move through the soil. Because the soil on Cape Cod is very sandy, contaminants migrate quickly.

Mr. Gregson said that the UT study was intended to provide specific information that could be used in the conceptual model and in computer models of how the contaminants move through the soil and groundwater at the Massachusetts Military Reservation (MMR). The study looked at what happens to the contaminants in the soil; how quickly they dissolve; how heat, cold, sunlight, and other environmental factors affect them; how and if they attach to soil particles as they move through the unsaturated zone; and how quickly or easily the contaminants could be removed from the soil.

Mr. Gregson stated that several things can happen to a contaminant once it's released in the environment: adsorption, whereby the contaminant basically sticks to the soil particles; volatilization (which doesn't occur much with explosives, but more with compounds such as TCE), whereby the contaminant volatilizes into the air spaces between the soil grains; and transformation, whereby the contaminant is transformed or changed either through biological processes or through chemical processes such as weathering or oxidation. Once the compound is dissolved, it's carried through the water and moves through the unsaturated zone to the water table. Once in the groundwater, there are several transport processes that can occur: advection, a process where the contamination is carried along in the groundwater; dispersion, a mechanical process by which the contamination is spread out due to varying flow paths; diffusion, a chemical process by which ions and molecules dissolved in a solution move from areas of higher concentration to areas of lower concentration; and dilution, a term that encompasses all of the above and means a general lowering of the concentration over time in a particular sample because of diffusion, dispersion, or other processes.

Mr. Gregson then displayed a figure of the IAGWSP conceptual site model and pointed out how dissolved contaminant percolates through soil and into the groundwater and then moves off downgradient. He also said that a key factor to understand is the amount of time it takes for the contaminant to get from the surface down to the water table, which is a function of how quickly the contaminant dissolves, and is estimated to be about one to three years. Once the contaminant enters the water table, dilution processes act on the contamination to spread it out as the plume migrates. Mr. Gonser referred to Mr. Schlesinger's comment about perchlorate contamination often being seen ahead of RDX contamination and said that this is because perchlorate goes into solution quicker and thereby gets a head start, not necessarily because it moves faster in the groundwater. Mr. Schlesinger asked if the RDX adsorbs to the soil particles. Mr. Gregson replied that once they're dissolved, both perchlorate and RDX don't adsorb very readily to the soil, although perchlorate may adsorb a little less readily than RDX.

Mr. Gregson then noted that the contaminants of concern (COCs) are explosives (RDX and HMX, as well as TNT, TNT breakdown products, 2,4-DNT, and nitroglycerine), and perchlorate. He also reviewed the following summary statements: RDX, HMX, and perchlorate dissolve and move through the unsaturated zone; perchlorate dissolves at a faster rate, as observed in field sampling and the nature of the plumes; RDX and HMX do not readily break down in the environment under biological processes; and the contaminants do not adsorb readily to the soil.

Mr. Schlesinger asked if it's correct that any RDX contamination at a concentration greater than 2 ppb must be cleaned up because it cannot naturally attenuate. Mr. Gregson clarified that RDX attenuates through physical processes such as diffusion and dispersion, as does perchlorate. Although there are no natural biodegradation processes in place at MMR, the RDX and perchlorate plumes do dilute over time because of diffusion and dispersion. Mr. Schlesinger asked if MNA is in use anywhere on MMR. Mr. Gregson replied that the monitoring would pertain to the mechanical and chemical processes of dilution. Unless the groundwater was amended in order to activate microbes, natural biodegradation would not be occurring at MMR.

Mr. Schlesinger then asked if it's possible to predict the size of the area of land that needs to be covered by a plume of known concentration in order for it diffuse and disperse to below cleanup levels. Mr. Gregson said that he thinks the IAGWSP's model can make that kind of prediction. He also noted that AFCEE is starting to build a database of actual conditions in its plumes to see how quickly they attenuate under those conditions.

Mr. Schlesinger asked if natural attenuation would be considered for the Central Impact Area plume. Mr. Gregson confirmed that a "no active remediation" alternative will be part of the feasibility study, to look at how the plume would disperse as it moves downgradient. Mr. Schlesinger asked if it would be possible to model what would happen, for example, to the 290-ppb RDX detection if the plume were allowed to go uncaptured. Mr. Gregson replied that once more information about the mass of the plume is available, that type of thing could be modeled.

Mr. Dow said that he wonders about the possibility of using a "power law" to predict the rate at which the particles dissolve, based on their size and their quantity. He asked whether the UT study looked at the rate at which things dissolve based on their particle size. Mr. Gregson said that he doesn't believe that the UT study looked at different particle sizes. He also said that it's difficult to come to grips with this issue in a place like the Central Impact Area, where a key piece of information that's missing is "how much particle is microscopic, versus small chunks, versus UXO." He further noted, however, that particles caused by high-order detonations (smoke essentially) probably already have dissolved away, such that detections in surface soil samples are the larger particulate. Mr. Dow said that he assumes that the Army must have done studies of UXO, and added, "It's just a thought."

Agenda Item #5. Open Discussion

Mr. Schlesinger expressed concern about the dwindling number of citizen IART members and asked what will happen if this trend continues. Mr. Murphy replied that next steps would have to be evaluated if it turns out that the membership recruitment effort that's being undertaken isn't successful, although he expects that it will be. Mr. Schlesinger suggested that it might make sense to ask the EPA regional director to amend the rule against having boards of selectmen appoint designates to the team. Mr. Murphy said that he doesn't think this is an issue since individuals have not been coming forward requesting to be part of the team, whether they were recommended by selectmen or any other organization. He again mentioned the planned recruitment effort and said that he doesn't think the regional director is going to deny anyone access to the team when there are only three citizen members who attend the meetings.

Ms. Grillo said that individuals have left the team for different reasons, including at least two people who moved off Cape. She also said that the recent recruitment effort doesn't involve any qualifiers pertaining to an approval process with the regional administrator, but is more an open invitation to join the IART.

Ms. Conron said that she thinks "it's exposure to what the committee is doing, not necessarily who selects you," and noted that EPA's recruitment effort in the town of Bourne brought forth about 12 to 15 applicants, while the Bourne selectmen's attempt to find interested individuals resulted in only two or three responses. She also said that she thinks the major stumbling block to retaining members is that the meetings are quite technical, and so people can lose their train of thought "if we don't keep it simple." She noted that the part of the meetings that she likes best is the "passionate human stuff," which attracts her just as much as wanting to know about the technical issues, and which lets people know that they're making a difference. Ms. Conron also said that she's amazed that none of the residents of Peters Pond Drive have expressed an interest in becoming part of the team, but added that she imagines that residents in the Forestdale neighborhood of Sandwich soon will be receiving letters from the IAGWSP since contamination was recently detected near that area. Mr. Murphy said that in that type of situation, the IAGWSP typically contacts residents to inform them of investigation activities in their neighborhood. However, in this case, he thinks that EPA could piggyback that notification with information about the IART and its need for additional citizen members.

Ms. Conron recommended focusing on "the wonderful things happening here" and the way citizens can help EPA and the IAGWSP just by having "common sense attitudes," asking "common sense questions," and ensuring an understanding of how the process is moving forward. She said that she thinks that people should know that a particular kind of background isn't needed to become an IART member, although she finds it interesting that most of the individuals from Bourne who applied for membership did have some of kind of science background.

Mr. Walsh-Rogalski questioned if there's something about the meeting format that could be changed in order to make it more attractive to people. Ms. Conron suggested always having the most interesting subjects at the top of the meeting, which in tonight's case she thinks were the local issues in Sandwich. She also said that she considers the educational items important, and thinks that an appropriate amount of time was devoted to tonight's fate and transport presentation, while others in the past have dragged on for too long, even for someone with a science background. Ms. Conron then clarified that she is not being anti-science, and actually thinks that participation in the IART integrates science into citizens' lives. She also noted, however, that she is amazed sometimes by how much she doesn't understand, and mentioned that she had a difficult time understanding the cross-section figures shown at tonight's meeting.

Mr. Schlesinger remarked that from his viewpoint, the most important items were not put first on tonight's agenda. He noted, for example, that he thought that the 290-ppb RDX detection should have been addressed as late-breaking news rather than being "buried in the presentation." And although he understands that the IAGWSP might consider this is a better approach from a public relations standpoint, he doesn't believe that that's the case from the public's perspective and from the perspective of trying to attract new team members. Mr. Schlesinger stated that people want to be involved in something exciting, and he believes that tonight's meeting could have been organized in such a way that the attendees became excited by the fact that the IAGWSP had found interesting information. He added that he thinks that presenting the most important information first would make the IAGWSP and the Army look good, not bad. Saying "Hey, we found this important information and we think the public ought to know about it," and doing so at the beginning of the meeting when the press and members of the public are still in attendance, would demonstrate that the military is a good steward of the environment.

Mr. Schlesinger suggested adjusting the rule about what makes late-breaking news, as he thinks that high concentrations of contaminant discovered at the base boundary should be included in that category. He also said that the residents of Sandwich might not want to be part of the IART simply because they don't know or understand what the consequences are and how they might be affected, and he thinks that organizing the meetings better to make them more interesting would be helpful. Mr. Schlesinger recommended that the IAGWSP reserve some time to pull together the most interesting and late-breaking items and organize them effectively into the format of the meeting "because it makes you guys look good and it interests the public."

Agenda Item #6. Adjourn

Mr. Murphy noted that the IART would meet next on Tuesday, August 23, 2005 at the Holiday Inn in Falmouth. He then adjourned the meeting at 8:51 p.m.