Impact Area Review Team
Agenda Item #1. Welcome, Agenda Review, Approval of March 28, 2006 IART Minutes
Ms. Bonarrigo convened the meeting at 6:00 p.m. and the Impact Area Review Team (IART) members introduced themselves. She asked if there were any changes or additions to the March 28, 2006 IART meeting minutes. No changes were offered and the minutes were approved as written.
Agenda Item #2. Responses to Action Items, Late-Breaking News
Ms. Bonarrigo confirmed that there was no late-breaking news to report, and that there were no comments or questions regarding Responses to Action Items from the March 28, 2006 IART meeting.
Agenda Item #3. Community Involvement Issues
Mr. Gregson announced that the Impact Area Groundwater Study Program (IAGWSP) is planning to publish a Plume Booklet, similar to the one produced by the Air Force Center for Environmental Excellence (AFCEE), as well as an Annual Report, which will include details of the remediation and investigation over the past year and will reference the Plume Booklet for more information. Both documents are scheduled to be published in late August/early September, and IART members will be provided with drafts for review and comment. Mr. Schlesinger mentioned that he hopes that the IAGWSP actually takes the IART's comments and uses them.
Agenda Item #4. Remediation & Investigation Update
Treatment System Construction Update
Mr. Gregson showed a map depicting the J-2 North RDX plume and pointed out the location of the source area, a disposal area that was removed as part of a Rapid Response Action (RRA) a couple of years ago. He reported that the J-2 North RRA for groundwater will involve three extraction wells located along the axis of the plume, a treatment plant, two mobile treatment units, granular activated carbon (GAC) and ion exchange resin filter media, and infiltration trenches along the sides of the plume to return the treated water to the aquifer. He also showed a map of the J-2 North perchlorate plume, which is more extensive than the RDX plume. Mr. Gregson noted that the J-2 North RRA groundwater system will treat a total of 375 gallons per minute (gpm) and will continue to operate until the final remedy is in place.
Mr. Gregson then showed a map of the J-3 Range RDX plume and said that the source area for that plume was also removed as part of an RRA. He noted that the RRA groundwater system for the J-3 Range plume involves three extraction wells - one is an existing well that AFCEE drilled but never used for its Fuel Spill 12 (FS-12) treatment system, and the other two are new wells installed by the IAGWSP. The extracted water will be pumped to IAGWSP treatment units (utilizing GAC and ion exchange) that are housed in the FS-12 treatment plant, and the treated water will be reinjected into the aquifer via AFCEE's FS-12 injection wells. Mr. Gregson noted that the J-3 Range plume treatment system will treat 175 gpm. He also said that both the J-2 North and J-3 Range RRA systems are scheduled for startup in fall 2006.
Mr. Gregson then showed several photographs of the ongoing construction and noted that the pipe, which is plastic HDPE pipe, is placed in the trench on top of a bed of sand and also covered with sand in order to help protect it. He also noted that the pipe is tested once it's been laid, and that the treatment vessels are expected to arrive at the end of April. Mr. Schlesinger inquired about the method for testing the pipe. Mr. Gregson replied that the pipe is pressure tested and, if any leaks are identified, the pipe is dug up and fixed.
Mr. Cambareri asked Mr. Gregson to name the firms conducting the drilling and pipe laying work. Mr. Gregson replied that the project is under contract to Environmental Chemical Corporation (ECC), a contractor that has done a lot of work for the IAGWSP and for AFCEE. He also said that he believes that ECC subs out the drilling work to D.L. Maher, and self-performs the excavation work.
Mr. Cambareri asked when the cleanup programs stopped using double-walled pipe. Mr. Minior replied that originally AFCEE installed double-walled pipe for transporting extracted groundwater to treatment systems. However, about four years ago it was determined that double-walled pipe wasn't necessary, given the way that single-walled pipe is constructed, and its pressures maintained and monitored. Mr. Minior noted that all the piping being installed for the Southwest plumes project is single-walled pipe.
Mr. Walsh-Rogalski inquired about expected influent and effluent concentrations associated with the J-2 North and J-3 Range RRA systems. Mr. Gregson replied that influent concentrations are expected to be in the tens of parts per billion (ppb) and the groundwater will be treated to nondetect.
Snake Pond Drive-Point Wells
Mr. Gregson showed a map of the J-3 Range RDX plume and noted that the IAGWSP has installed a series of drive-points south of the Snake Pond in order to answer the question of whether the plume is flowing under the pond and continuing to migrate south. The investigation looked at a target depth of 140 feet below water table (bwt), where the plume would be expected to be seen were it flowing under the pond. Each of the drive-points reached that depth and samples collected from there all tested nondetect for explosives and perchlorate.
Mr. Gregson also reported that in drive-point 4 (DP-4), perchlorate was detected at 0.9 ppb at the water table. Given the location and depth of that detection, however, it's highly unlikely that that contamination tracks back to the base, as it is too distant and too shallow. Mr. Gregson also noted that one possible source for that perchlorate is a possible septic tank associated with a small comfort station at the Snake Pond beach.
Mr. Gregson then showed a U.S. Geological Survey (USGS) figure that illustrates how groundwater interacts with ponds on Cape Cod and pointed out how any perchlorate related to the J-3 Range plume that reached the southern side of Snake Pond would be at a significantly greater depth than the 0.9 ppb detection. He also noted that Snake Pond surface water is sampled routinely and has never had any detections of explosives or perchlorate.
Mr. Schlesinger asked when the Snake Pond surface water would be tested next. Mr. Gregson replied that he believes sampling will occur next in late April/early May. Mr. Schlesinger also asked about the sampling locations. Mr. Gregson said that the sampling would be conducted at an area at the beach and at another location near Camp Good News - places where people are likely to go swimming.
Mr. Dow noted that Denis LeBlanc of USGS found that higher conductivity levels exist at areas with septic system contamination. Mr. Dow then asked if the IAGWSP found higher conductivity levels in the area of the 0.9 ppb perchlorate detection near Snake Pond. Mr. Gregson replied that specific conductivity is a fairly routine measurement, so he thinks that information is probably available and can be provided. He also noted that given the location of the drive-point on the shore of the pond, the comfort station he'd mentioned is probably the only potential upgradient source.
Agenda Item #5. Ammunition Supply Point Rapid Response Action
Mr. Gregson stated that tonight's presentation begins the Ammunition Supply Point (ASP) RRA informal public comment period, which runs through May 9, 2006. He noted that the ASP is a very small site, and the proposed RRA involves a limited amount of work - the investigation of some geophysical anomalies and the excavation of a small area of lead-contaminated soil - after which it's anticipated that no further action will be required. Mr. Gregson noted that since the mid-1950s the ASP, which is located along the western edge of the base, has been serving as the location from which munitions, small arms, ammunition, explosives, and other training munitions have been dispensed.
Mr. Gregson reported that investigation at the ASP began in 2001, with the area being fairly extensively studied as part of the Munitions Survey Project (MSP) Phases II and III. He noted that the MSP involved the use of ground-based geophysics, which identified five suspected disposal sites warranting additional investigation near the ASP. Site investigation work also included witness interviews and the examination of historic aerial photographs. The five areas that were identified are: Area A, a 2,000 square meter area that's mostly flat and free of vegetation; Area B, a gravel pit about 1,100 square meters in size; Area C, a damp and vegetated area, about 1,100 square meters in size; Area D, an area along the edge of the ASP, about 1,500 square meters in size, which includes both an open area and into the wood line; and Area E, which is about 760 square meters in size.
Mr. Gregson reported that based on signal strength and proximity to other anomalies, 83 anomalies in the five areas were selected for investigation by excavation. The majority of the recovered material was miscellaneous metallic debris and scrap. In addition, one practice grenade was found at Area D, and two small disposal sites were discovered - one at Area A where 342 expended jet-engine starter cartridges and igniter tubes were found, and another at Area E where a crushed 55-gallon drum containing ash and burnt small arms ammunition and pyrotechnics was found. As part of Phase III of the MSP, the IAGWSP looked at additional areas to investigate in order to fill data gaps from Phase II. And based on that information, the ASP RRA has been proposed.
Mr. Walsh-Rogalski said that he remembers an interview with an explosives ordnance disposal (EOD) technician in which the witness testified about a small arms ammunition burial site behind the ASP. Mr. Gregson replied that it's hard to know if exactly what the witness mentioned was found. However, a wooden box containing 105-mm cartridge cases and propellant igniter tubes was found in Area C. Mr. Gallagher added that some of the anomalies identified through the geophysical work have not yet been investigated, including some of those that the witness suggested should be evaluated.
Mr. Gregson continued with his presentation by reporting that soil samples collected from Areas A and C tested nondetect for explosives, but bis-2-ethylhexyl phthalate (BEHP) was detected at a concentration of 31.3 ppb at Area A. In addition, lead was detected at 461 parts per million (ppm). Mr. Gregson noted that the lead-contaminated soil would be excavated as part of the ASP RRA.
Mr. Dow asked if 31.3 ppb is considered a level of concern for BEHP. Mr. Gregson replied that that it is typically thought of as a lab contaminant, and Mr. Gallagher added that that number does not exceed any action level.
Mr. Gregson then reported that the ash material found in the drum was tested and showed 2,6-DNT, some volatile organic compounds (VOCs) - acetone and chloromethane, BEHP, di-n-butyl phthalate, some dioxin, and six metals. The material was transported off site for disposal. Mr. Gregson also noted that soil samples collected from underneath the wooden box containing 105-mm cartridge cases and propellant igniter tubes found in Area C tested nondetect.
Mr. Gregson went on to report that while no monitoring wells had been installed specifically to evaluate the ASP area, downgradient monitoring wells (MW-83 and MW-84) were considered as part of the assessment that was done for the RRA. He noted that the wells are significantly downgradient of the site, but had been profiled from water table to bedrock, and with five screens at each location they provide fairly good vertical coverage. He also said that according to particle tracking, if a major plume was emanating from the ASP area, the expectation is that it would be seen in MW-84.
Mr. Schlesinger inquired about wells downgradient of MW-84. Mr. Gregson referred to the "M" series of wells that were sampled as part of the Western Boundary investigation. He also noted, however, that those well screens are probably too shallow to detect anything coming from an area as far upgradient as the ASP. Mr. Schlesinger then inquired about any drinking water wells downgradient of the ASP. Mr. Gregson referred to the map, pointed out the Bourne water supply wells up to the north, and said that no additional supply wells had been identified "down in this area."
Mr. Schlesinger noted that the IAGWSP seems to be basically relying on just the one data point (at MW-84) to know whether there might be a problem downgradient of the ASP. Mr. Gregson acknowledged that MW-84 is quite a distance from the ASP and is only one data point. Mr. Gallagher added that as part of the IAGWSP's response to U.S. Environmental Protection Agency (EPA) and Massachusetts Department of Environmental Protection (MassDEP) comments, a limited groundwater investigation in the area of the ASP has been proposed. Mr. Schlesinger asked if the public could see that plan. Mr. Gregson said that once the regulators come to agreement on the plan, it could be presented to the IART. Mr. Schlesinger objected to that approach in that he believes it would make the IART's advice meaningless to be presented with a plan that's already been determined. Mr. Gregson offered to send out to IART members, via e-mail, a map showing the proposed monitoring locations for the ASP groundwater investigation.
Mr. Dow asked if the ASP groundwater monitoring plan would include lead analysis. Mr. Gregson replied that although he's uncertain whether agreement has been reached regarding analytes, he believes that lead would be an analyte given that it's one of the contaminants of concern in soil. Mr. Dow said that he mentioned this because although lead is probably not very mobile in soil, when bacteria convert it to methyl-lead, which often occurs, it's known to become much more mobile.
Mr. Gregson stated that the proposed RRA involves a couple of components: investigating selected anomalies found as part of the geophysical investigation, including a subset of some of the smaller anomalies that the regulators want investigated; and removing a small area of lead-contaminated soil. He again mentioned that the informal public comment period begins tonight and runs through May 9, 2006. He also said that the IAGWSP will work to resolve comments from the regulators and any additional comments received during the public comment period. He noted that field work is expected to begin later this summer and the contaminated soil will be shipped off site. Mr. Gregson noted that comments could be submitted to him this evening or to Pamela Richardson at the IAGWSP office via email, at Pamela.email@example.com.
Mr. Walsh-Rogalski asked whether the source of lead in the soil is known. Mr. Gregson replied that while it isn't known specifically, it's believed that small arms ammunition is a potential source.
Mr. Schlesinger asked for and received from Mr. Gregson confirmation that IART members would receive by email information on groundwater monitoring locations associated with the ASP in time to review and provide comments during the public comment period.
Agenda Item #6. Groundwater Monitoring Plans
Central Impact Area
Mr. Gregson reminded the group that the IAGWSP's monitoring program has transitioned from a base-wide long-term monitoring program to site-specific monitoring plans. Two types of monitoring plans are now being used: a performance monitoring and evaluation (PME) plan, which involves treatment system monitoring, hydraulic monitoring, and contaminant monitoring, and pertains to plumes with cleanup systems in place; and an interim groundwater monitoring (IGM) plan, the intent of which is to characterize plume nature and extent and support remedial decision-making.
Mr. Gregson then noted that the Central Impact Area (CIA), a 330-acre source area located within the Impact Area, was defined based on density of unexploded ordnance (UXO), historic aerial photographs, soil samples, particle tracking, density of craters seen in aerial photographs, witness interviews, and knowledge of past military practices and training activities. The CIA contains numerous targets that received both artillery and mortar fire from the early 1900s through 1988, after which training at the CIA continued with low-intensity training (LITR) rounds, believed to be the source of perchlorate at the CIA, given that the spotting charges in those rounds contained perchlorate. Mr. Gregson also noted that firing of LITR rounds ended in 1997 when EPA issued its administrative orders.
Mr. Gregson reported that as part of the CIA investigation, 308 well screens at 126 locations have been installed and sampled, more than 2,000 soil samples have been collected from 300 separate locations, and both aerial magnetometry (air mag) and ground-based geophysical surveys have been conducted. In addition, ordnance density studies have been conducted, as have focused investigations at two target areas, as well as investigation into two potential ordnance disposal sites - one at the SCAR (sub-caliber aircraft rocket) site and another at the Eastern Test site.
Mr. Gregson noted that a number of investigation reports have been issued, including the draft CIA Groundwater Remedial Investigation (RI) Report, which is currently under agency review. He also said that the RI identified some of the contaminants of concern (COCs) at the CIA, including: RDX (the maximum concentration seen in the CIA lately was 40 ppb, but typical levels are less than 10 ppb); perchlorate, typically at less than 5 ppb; HMX, with the maximum detection being 9.7 ppb (the health advisory for HMX is 400 ppb): and TNT and TNT breakdown products.
Mr. Gregson stated that ongoing field investigations to fill data gaps include: the installation of drive-points to collect samples at the water table and help refine the current source areas of explosives and perchlorate to groundwater: UXO density test plots; additional soil sampling; and an evaluation of explosive particulate distribution in soil. The soil RI report is scheduled to be prepared after completion of the current field program, with a draft to come out in December 2006. Also, a feasibility study (FS) screening report that looks at different cleanup alternatives is currently being prepared in consultation with the regulators.
Mr. Gregson then noted that the objectives of the IGM plan for the CIA are: to continue to monitor potential migration at the leading edge of the RDX and perchlorate plumes; to monitor locations at the lateral edges of the RDX and perchlorate plumes; to monitor water table detections of RDX and perchlorate as indicators of soil source areas; and to monitor the overall trends in RDX and perchlorate concentrations in groundwater while the investigation and FS are being completed.
Mr. Gregson stated that the IAGWSP reviewed how RDX and perchlorate concentrations were changing (whether increasing, decreasing, or staying the same) and developed a CIA monitoring program that includes wells to be sampled annually and wells to be sampled semiannually. He displayed a map showing both the semiannual and annual wells and the direction of groundwater flow, and noted that 19 well screens will be monitoring annually for explosives, 13 will be monitoring annually for perchlorate, 35 will be monitored semiannually for explosives, and 17 will be monitored semiannually for perchlorate. He noted that EPA has submitted its comments on the plan, while MassDEP's comments are forthcoming.
Mr. Mullennix asked whether Mr. Gregson thinks that enough well screens were included in the plan. Mr. Gregson replied that he does think so and then spoke of being in the phase of looking for major increases or decreases in concentrations in particular wells or major changes in the extent of contamination. Mr. Mullennix inquired about any preliminary findings. Mr. Gregson said that although concentrations at some wells have changed a little bit, in general concentrations are remaining fairly consistent with what they've been historically. He also noted that because the capture zone for any future pump-and-treat system would encompass the entire area, current monitoring is really looking for any major changes to the plumes.
Mr. Mullennix then inquired about the timing of a recommendation for remediation. Mr. Gregson replied that the IAGWSP will work through the RI reports, the FS screening report process, and the FS itself, which involves the evaluation of alternatives that will lead to a cleanup decision - probably more than a year from now.
Mr. Schlesinger inquired about the southwestern portion of the CIA, near MW-104, which extends beyond the plume outline. Mr. Gregson replied that the purple line depicts the boundary of the CIA based on the lines of evidence he'd mentioned earlier (aerial photos, soil samples, particle tracks, and so forth) and due to "whatever criteria" that line extends down into that area to include it within the CIA boundary. Mr. Schlesinger suggested that the line must be moving at the rate of 365 feet a year, assuming that it's moving one foot per day. Mr. Gregson replied that that is the maximum rate that it would migrate. He also noted, however, that the process of attenuation is ongoing such that the leading edge of the plume could be stationary, given that there's not enough mass to drive it forward. He said that monitoring at the downgradient locations is intended to confirm that there isn't a significant migration of the plume's leading edge.
Mr. Schlesinger then inquired about the color-coding of wells shown on the RDX map for the CIA. Mr. Gregson explained that wells depicted in green have been targeted to monitor the migration of the leading edge of the plume, while those depicted in red were selected to monitor changes in RDX concentrations, and those in yellow to monitor the lateral edges of the plume. Mr. Schlesinger asked when the next sampling round is scheduled to occur. Mr. Gregson replied that the semiannual wells will probably be sampled next in late spring/early summer and then again in late fall/early winter.
Mr. Schlesinger also asked about any effort to connect CIA contamination with other downgradient areas of contamination. Mr. Gregson pointed out the nondetect wells upon which the extent of the CIA plume is based. He also noted, however, that it's believed that the RDX contamination at the Northwest Corner investigation area might track back to the Impact Area, and while a connection hasn't been confirmed yet, there is some additional work to try to answer that question. Mr. Schlesinger asked if that work is ongoing or on the backburner for the time being. Mr. Gregson said that he thinks that some additional investigation is planned upgradient of the Northwest Corner. He also noted that a drive-point effort had been undertaken there, but with only some success because of the large boulders that exist on the moraine; therefore, conventional wells will probably be needed in that area.
Mr. Minior noted that the RDX map is based on data through May 2003, and inquired about a plan to update that figure. Mr. Gregson noted that a request to update the figure has been made, the IAGWSP is considering it, and it "probably wouldn't be a bad idea." He also explained, however, that because some data cutoff point is needed when going into the modeling and FS process, that was the figure that was used. Mr. Minior then asked if the perchlorate map would be updated to show the 2 ppb plume contour line, as the state is promulgating a 2 ppb perchlorate standard. Mr. Gregson replied that that line should be shown on updated perchlorate maps.
Mr. Schlesinger asked if updated CIA plume maps would be prepared in time to be included in the upcoming Plume Booklet. Mr. Gregson replied that he's uncertain about the timing, but added that the IAGWSP would want to show the public if the plume has migrated or shrunk significantly. Mr. Schlesinger strongly urged the IAGWSP to include updated figures in the Plume Booklet as he thinks it's important that the public not be provided with a "diminished view of the actual situation."
Mr. Dow asked why the RDX contamination from the CIA is so much farther advanced than the perchlorate contamination. Mr. Gregson replied that it's believed that this has to do with the timing of the deposition of explosives and perchlorate. RDX was fired into the Impact Area from around the 1940s until 1988, and after that perchlorate was fired as part of the spotting charges on LITR rounds. Essentially RDX had a head start, and is therefore farther advanced.
Mr. Dow then asked how the conceptual model explains what he called the "narrow perchlorate plume in the Northwest Corner." Mr. Gregson noted that the narrow plume in the Northwest Corner is not a perchlorate plume, but an RDX plume. Mr. Dow said that it's his understanding that perchlorate is commingled with that RDX plume, which is believed to track back to the base. Mr. Gregson clarified that the RDX plume at the Northwest Corner is much deeper than the perchlorate contamination there. He noted that there were only a handful of deep perchlorate detections in that area. He also said that a deep perchlorate plume at the Northwest Corner hasn't been mapped; rather, the perchlorate plume that's been mapped there is shallow, at the water table.
Mr. Dow remarked that that is not his recollection of what was found at the Northwest Corner. He also said that if one were to presume that the deep perchlorate and RDX at the Northwest Corner is from the CIA, either the leading edges of the CIA plume as depicted are inaccurate, or there's a detached plume at the Northwest Corner that's no longer linked to the CIA. Mr. Dow then asked if the IGM plan for the CIA is adaptive such that it would account for changes that occur in what is the "proposed CIA plume for perchlorate and RDX combined." Mr. Gregson said that monitoring for perchlorate is part of the IGM plan for the CIA. He then referred to the perchlorate map, pointed out the nondetect contour line, said that there's a significant number of wells that are nondetect for perchlorate downgradient of the Impact Area, and also noted that there are very few perchlorate detections above 2 ppb. He also said that while there have been a few deeper detections of perchlorate in the Northwest Corner, he doesn't think they're mappable, and he doesn't think there's any connection between that perchlorate contamination and what's being seen in the Impact Area. Mr. Pinaud asked if Mr. Gregson had with him a cross-section figure that would help with this discussion. Mr. Gregson said that he didn't think so, but could look.
Mr. Panni referred to the CIA perchlorate map and pointed out an edge of the plume that, based on recent data, has expanded and so requires some updating. Mr. Gregson said that the maps would be updated to reflect those data. He also noted, however, that with respect to the FS and selection of a remedy, it may not matter much "that this well goes from nondetect to 0.4 ppb," for example. He indicated that it's important to assess how such changes might affect cleanup decisions.
Mr. Schlesinger remarked that because the IAGWSP keeps presenting the same information, the public's perception is that the CIA plume hasn't changed. However, there have been changes, and it's important that the IART be kept informed of those changes, otherwise IART members are "offering advice on history," which he considers ridiculous. Mr. Schlesinger then urged the IAGWSP to provide an updated CIA plume map in time for the May IART meeting. Mr. Gregson said that although he isn't sure what the status of producing a new map will be between now and the next IART meeting, this is clearly an important issue to the IART members, and one that the IAGWSP will consider.
Mr. Walsh-Rogalski suggested that even though a data point might not be relevant in terms of remedy selection, it can be useful in terms of "seeing the whole picture," and he thinks that everyone would agree that understanding the data is significant. He also said that he would rather err on the side of "putting more data down rather than less data."
Mr. Gallagher said that Mr. Panni is right that the perchlorate plume has migrated downgradient. He also noted that in cross-section the wells where perchlorate is being detected "make perfect sense," implying that the plumes were well drawn to begin with. He further noted that those low-level detections in what were formerly downgradient wells were taken into account while developing the monitoring plan. That is to say, the plan that's being proposed is not necessarily locked into the 2003 plume depictions. Mr. Gallagher also mentioned the 2003 data cutoff point when the plumes were digitized and the modeling effort began. He explained that it would be difficult, if not impossible, to go back and re-digitize the plume shells and redo the modeling every time there's a new detection or slight change in the plume depiction, and therefore the IAGWSP has been living with those plume depictions "for a while now."
Former A Range
Mr. Gregson showed a map of the Former A Range, located on the northwestern edge of the base, and pointed out the CIA plumes depicted on the previous figures, and some of the wells that were installed to assess the CIA and the Former A Range itself. He then noted that the Former A Range, which is also known as the Anti-Tank Gravity Range, is an inactive anti-tank artillery and rocket range that was originally constructed in 1941 and was used up until the 1970s. Mr. Gregson noted that the range is interesting in that its use involved the placement of targets on mail cars that were allowed to roll down a small set of railroad tracks, via gravity, and were fired upon by troops as they moved down the hill. He also reported that the types of munitions used at the range up until the late 1960s were: 37-mm armor-piercing and high explosive (HE) rounds, 40-mm rounds, 75-mm HE rounds, 90-mm anti-aircraft rounds, and 3.5-inch practice rockets. Then the range was converted to a machine-gun training range in the early 1970s, when it was used for 50-caliber machine guns.
Mr. Gregson reported that remedial investigation work at the Former A Range has included the installation of three new monitoring wells (MW-149, MW-249, and MW-206), sampling of 16 existing CIA well screens at eight different locations, the collection and analysis of more than 200 soil samples, and air mag and ground-based geophysical surveys. He noted that a draft RI report for the Former A Range is currently being prepared, and results to date indicate that TNT, TNT breakdown products, and metals are present in soil, as are some VOCs. In addition, RDX and HMX have been detected in some of the post-Blow-in-Place (BIP) samples, and may be from the explosives used for those detonations. Mr. Gregson further noted that the metals that were detected were consistent with the use of the range for small arms firing. He also said that TNT and its breakdown products were detected at concentrations below 0.5 ppb in one well, MW-249, where there'd also been a one-time detection of RDX at 0.3 ppb and 1,3,5-trinitrobenzene at 0.3 ppb, in June 2005. A one-time detection of perchlorate also occurred in MW-249. In addition, RDX has been detected in that part of the CIA plume that underlies the Former A Range.
Mr. Gregson noted that the objective of the IGM plan for the Former A Range is to monitor groundwater to ensure that the low-level detections and nondetects that have been seen in the wells are consistent, while the RI is being completed. He also said that the proposed contaminant monitoring involves annual sampling of three well screens for explosives and annual sampling of one well screen for perchlorate. Mr. Gregson said that the IAGWSP is working to resolve regulatory agency comments on this monitoring plan.
Mr. Schlesinger asked if the Former A Range map is showing a three-year-old plume shell. Mr. Gregson clarified that no plume has been identified at the Former A Range; however, that portion of the CIA plume included on the map is the same as the other CIA depictions shown this evening. Mr. Schlesinger also inquired about any plans to continue the investigation farther, toward Deep Bottom Pond Road. Mr. Gregson replied that it's believed that the groundwater has been adequately characterized for the purposes of completing the RI report, but that type of question will be considered as the process moves forward. Mr. Schlesinger then asked if it's correct that the Former A Range area overlaps with the CIA study area. Mr. Gregson confirmed that that is correct, but also noted that the wells associated with the Former A Range groundwater monitoring plan are being monitored specifically for that plan.
Mr. Schlesinger then asked if there are screens in MW-206, MW-249, and MW-149 at an adequate depth to monitor for information related to the CIA plume as well. Mr. Gonser replied that, as noted on the CIA plume, those wells are being monitored for that plume and therefore must be positioned properly for that purpose.
Mr. Schlesinger then inquired about any plan to monitor in the Deep Bottom Pond area for the CIA plume. Mr. Gregson replied that the CIA process is in the middle of the RI phase, there are either low-level detections or nondetect wells that indicate the leading edge of the plume, and therefore there seems no need to drill additional wells near Deep Bottom Pond to assess the CIA plume.
Mr. Schlesinger remarked that it seems to him that there is "significant reticence" on the part of the IAGWSP to connect the CIA plume with the contamination at the Northwest Corner. He also said that he wishes that reticence would cease so that the source of contamination could become known and it could be properly understood how best to remediate the full extent of contamination.
Mr. Gregson replied that the IAGWSP and the regulatory agencies have been working on the investigations for a long time and carefully reviewing data as they become available. And the point has been reached for both the CIA and Northwest Corner where it's believed that the extent of contamination has been adequately defined for the purpose of proceeding with the process of deciding what needs to be done in terms of cleanup. He noted that the only data gap at this time pertains to the RDX contamination at the Northwest Corner, and there is an effort to confirm whether or not there's a connection between that RDX and the CIA. Mr. Gregson stated that he disagrees with Mr. Schlesinger's assertion that the IAGWSP is closing its eyes to trying to assess the extent of contamination associated with the CIA and Northwest Corner plumes, or any other plumes, and he is certain that the regulatory agencies wouldn't allow the cleanup program to ignore areas that require additional investigation. He also said that although probably not all of the data needed to complete the program have been collected, the IAGWSP and the regulators do try to come to agreement as to when there are enough data to move forward in the process, and that conclusion has been reached with respect to the CIA and the Northwest Corner, as well as other plumes on the base.
Mr. Pinaud recommended including an update on the Northwest Corner RI on the May IART agenda and showing both the CIA and Northwest Corner maps so the potential connection between the two areas can be discussed.
Mr. Olson said that while he thinks it's a good thing that the IAGWSP draws its plumes to nondetect, it could be the cause of some issues in this situation. He explained that drawing the plumes to nondetect sort of creates the impression that a detect "is something that's really bad"; whereas, if the plumes were drawn to a risk-based cutoff, a lot of those very low concentrations wouldn't even be shown on the map. Mr. Olson reiterated that although he does consider it good to draw plumes to nondetect, he also thinks that it's important to keep in perspective when defining the extent of contamination that "thousands of feet of a plume…between…1 ppb and nondetect" is not necessarily a bad thing, and that fact in itself will play into the FS decision-making process. He added that drawing the plumes to nondetect creates some difficulty in trying to end the process of investigation and move on with making a cleanup decision.
Mr. Dow mentioned that the most recent Plume Cleanup Team (PCT) meeting included a presentation on when cleanup is considered completed. He also said that one of the underlying philosophies of AFCEE's Installation Restoration Program (IRP) is restoration of the aquifer. Once a maximum contaminant level (MCL) or Massachusetts MCL (MMCL) is achieved through cleanup, the IRP does a risk assessment and evaluation to determine whether it's technically feasible "to go beyond that to the next step" and he thinks that the IAGWSP should adapt a similar strategy.
Mr. Olson said that he doesn't disagree that the goal is aquifer restoration. He also noted, however, that although he thinks it's a good idea to continue to draw the plumes to nondetect, it can create problems. For example, when EPA did some sampling in the Peters Pond area and lowered the method detection limit by an order of magnitude, the plume that was drawn increased by three times, when the situation hadn't really changed. Mr. Olson reiterated that he doesn't disagree with the goal of aquifer restoration, but thinks that the process toward that should be done one step at a time, just as AFCEE is doing in its cleanup program.
Mr. Minior noted that all of the plume depictions in AFCEE's Plume Booklet are based on MCLs, MMCLs, or in the case of RDX, the health advisory level - and therefore are truer depictions in terms of water that's not safe to drink. He added that if the "halo" around AFCEE plumes were shown (i.e. the area which is less than the drinking water level, but within detectable limits), the plumes would look significantly larger, despite that those low levels are not going to cause any health problems. Mr. Minior also said that depicting plumes in plan view, without looking at the cross-section, can be misleading in that little plumelets or lobes are not seen as separate areas of contamination, but instead are over-exaggerated in a one-dimensional plan view. Mr. Minior then encouraged everyone to take a look at how AFCEE depicts plumes in its publications. He also noted that the 2005 IRP Annual Report just came back from the printer today.
Mr. Cambareri acknowledged that FS efforts have begun with the plume depictions as they are, and that some of the contamination is moving downgradient. He then said that it seems to him that "both these things must move in tandem," such that the FS moves forward with the plume depictions as they are, but while keeping track of the migration of the plumes. He also noted that he thinks the IAGWSP's strategy to draw the plumes to nondetect is appropriate, and that he's anxious to see new renditions of the plumes as the process moves forward. Mr. Cambareri also recommended that cross-section figures be part of future presentations, as they will be important to see.
Agenda Item #7. Open Discussion
Mr. Gonser reported that the U.S. Army Environmental Center's (AEC's) second round of sampling at Bravo Range yielded a 22 ppb tungsten detection at the same monitoring well where tungsten was detected at 15 ppb during the first sampling round. He also noted that the second round was fairly consistent with the first, that no lead was detected in any of the samples, and that a third round of sampling is scheduled to be conducted this month.
Mr. Schlesinger inquired about the U.S. Center for Health Promotion and Preventive Medicine (CHPPM) study. Mr. Gonser replied that CHPPM is conducting a toxicological study pertaining to tungsten, results of which are expected this summer. Mr. Schlesinger noted that at this time then there's no real perspective on what a 22 ppb tungsten detection means. Mr. Gonser confirmed that that is so.
Mr. Walsh-Rogalski inquired as to the total number of monitoring wells sampled, and whether there were any other tungsten detections. Mr. Gonser replied that four wells were sampled - two of which were background wells where no detections were expected, and one of which isn't particularly suitably located and therefore no detection was expected there either, and the other of which was the one with the 15 ppb and 22 ppb detections. Mr. Walsh-Rogalski asserted that there's been 100% detection in all significant wells. Mr. Gonser said that that's a fair statement, given that tungsten was detected in only the one best-located well.
Mr. Olson asked if it's correct that lead was detected in the first sampling round. Mr. Gonser confirmed that there were some very low-level detections of lead (almost at background) in the first sampling round, but in the second round all the wells tested nondetect for lead. Mr. Olson asked if that applies just to the wells, or if the lysimeters were sampled a second time also. Mr. Gonser clarified that he was referring to just the wells.
Mr. Schlesinger inquired about any effort to determine whether the tungsten is moving downgradient. Mr. Gonser replied that given the tungsten that's been detected, AEC has decided to expand its study and is currently working with the Cold Regions Research & Engineering Laboratory in New Hampshire and the USGS to develop a plan for additional sampling, and for scientific analysis, including modeling, testing, transport, and so forth. He also noted that several new wells will be installed on the Bravo and Charlie Ranges, and probably on the Sierra Range also.
Mr. Dow mentioned having spoken previously to Mr. LeBlanc of the USGS about how there can be parts-per-million levels of tungsten in the pore water and only parts-per-billion levels in the saturated zone. He said that Mr. LeBlanc's explanation was that there are tungsten hotspots in the pore water, which get washed down into the saturated zone during rain events where it becomes diluted by the groundwater, thereby reducing the concentrations. He said that Mr. LeBlanc had also noted that because only hotspots occur in the pore water, the mass of tungsten is not that great to being with; when that relatively low mass is combined with the groundwater dilution factor, the result is ppb levels in groundwater and ppm levels in pore water. Mr. Gonser said that this is good information that he will pass along to AEC, although Mr. LeBlanc is working as a consultant to AEC and will likely pass along that information himself.
Mr. Schlesinger requested that, as standard protocol, IART presentations include cross-section figures along with plan view figures. He also noted that he's made this request repeatedly in the past and feels strongly that the availability of cross-sections would "really solve a lot in terms of understanding…"
Agenda Item #7. Adjourn
Ms. Bonarrigo noted that the IART would meet next on May 23, 2006 at the Best Western Hotel in Bourne. She then adjourned the meeting at 8:13 p.m.
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