REMEDY OPERATION STATUS REPORT October March 2003 FORMER VARIAN FACILITY SITE 150 SOHIER ROAD BEVERLY, MASSACHUSETTS 01915

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1 REMEDY OPERATION STATUS REPORT October March 2003 FORMER VARIAN FACILITY SITE 150 SOHIER ROAD BEVERLY, MASSACHUSETTS MA DEP SITE NO Tier 1B Permit No. P23730 April 29, 2003 Shaw Environmental, Inc. Prepared By: Reviewed By: David E. Walker, PG Geologist Lawrence J. Nesbitt, P.E. Project Manager Raymond J. Cadorette Environmental Scientist Timothy W. Kemper, PE Licensed Site Professional

2 CONTENTS 1.0 INTRODUCTION DESCRIPTION OF INSPECTION AND MONITORING ACTIVITIES (310 CMR (1)) Remedial System Monitoring and Inspection Monitoring of Physical Parameters in Groundwater Groundwater and Surface Water Sampling RESULTS OF INSPECTION AND MONITORING ACTIVITIES (310CMR (5)) System Monitoring and Inspection Results Groundwater Physical Parameter Results Groundwater and Surface Water Analytical Sampling Results SIGNIFICANT MODIFICATIONS TO THE INSPECTION AND MONITORING PROGRAM (310 CMR (2)) DESCRIPTION OF PROBLEMS AFFECTING THE PERFORMANCE OF THE REMEDIAL ACTION (310 CMR (3)) MEASURES TAKEN TO ADDRESS PROBLEMS AFFECTING THE PERFORMANCE OF THE REMEDIAL ACTION (310 CMR (4)) MODIFICATIONS TO THE REMEDIAL ACTION (310 CMR (3)) Longview/Hill Street Area Tozer Road South of Route Additional Injection Points West of the Building 3 and 6 Treatment Areas Proposed Additional Injection and Monitoring Well Installations Revised Permanganate Volumes PSL 10 Treatment Area Modification Tozer Road Area CONCLUSIONS REFERENCES...2 Figures 1. Site Location Map 2. Site Plan 3. PCE, TCE, & 1,2-DCE Groundwater Sampling Results Shallow Overburden Wells 4. PCE, TCE, & 1,2-DCE Groundwater Sampling Results Deep Overburden Wells 5. PCE, TCE, & 1,2-DCE Groundwater Sampling Results Bedrock Wells Tables 1. Permanganate Injection Volumes Actual 2002 and Proposed Water Quality Data VOC Results 3. Water Quality Data Chloride, Iron, and Manganese Results 4. Permanganate Concentrations in Groundwater Appendices A. MADEP Comprehensive Response Action Transmittal Form (BWSC-108) B. Field Work Methods and QA/QC Procedures C. Groundwater Gauging And Physical Parameter Data D. Analytical Laboratory Reports

3 1.0 INTRODUCTION On behalf of Varian Medical Systems, Inc. (Varian), Shaw Environmental, Inc. (Shaw) has prepared this semi-annual Remedy Operation Status report for the former Varian facility located at 150 Sohier Road and other properties located in the vicinity in Beverly, Massachusetts (the Site). A Site Location Map illustrating the location of the former Varian facility is attached as Figure 1 and a Site plan is attached as Figure 2. This semi-annual Remedy Operation Status report summarizes activities conducted during the period of October 2002 through March A Massachusetts Department of Environmental Protection (MADEP) Comprehensive Response Action Transmittal Form (BWSC-108) is presented in Appendix A. Shaw (formerly IT Corporation) submitted a Phase IV Remedy Implementation Plan (Phase IV Plan; IT, 2001) to the MADEP for the above referenced Site in December The Phase IV Plan described proposed remedial actions for addressing volatile organic compounds (VOCs) in soil and groundwater at the subject Site. In situ oxidation of VOCs in soil and groundwater by permanganate solution was chosen as the best remedial alternative for the Site. Construction activities related to the remedial treatment program began in December Initial implementation of the Comprehensive Response Action, including the injection of permanganate solution, began in July The primary areas targeted for remedial action are those where VOCs are present and have the potential to migrate north of the former Varian facility into a GW-1 groundwater area (identified as a Potentially Productive Aquifer). These treatment areas include the following Potential Source Locations (PSLs) at the former Varian facility: PSL 5 Potential former septic tank near Building 3 PSL 6 Potential former septic tank/leach field near Building 6 PSL 9 Inspection pit near Building No. 3 PSL 10 Historic Disposal Area South of Building 5 PSL 11 Building No. 3 laboratory PSL 12 Potential former lime pit near Building 3 Downgradient non-source areas of the Site with groundwater containing VOCs that may contribute to the presence of VOCs in the GW-1 area are: The localized area located north of the former Varian facility and Route 128 The area located along Tozer Road north and south of Route 128 Remediation activities for the areas listed above are intended to mitigate groundwater impacts so that groundwater concentrations in the GW-1 area north of Route 128 are reduced and remain below drinking water quality standards. The goal of the planned remedial actions is to reach a Permanent Solution, as defined by the Massachusetts Contingency Plan (310 CMR ), Class A Response Action Outcome (RAO) may be submitted for the Site.

4 A Phase IV As-Built and Final Inspection Report (Shaw, 2002) detailing initial Phase IV activities including permitting, well installation, construction of the remedial treatment system and initial implementation of comprehensive actions was submitted to the MADEP in October The Phase IV As-Built and Final Inspection Report also provided results of additional soil and groundwater analyses, identified modifications made to the Phase IV Plan, and documented the final inspection of the remedial system. In December 2002, Varian submitted a Remedy Operation Status Opinion, which stated that the performance standards for Remedy Operation Status, specified in 310 CMR (2), have been achieved and will be maintained at the Site. A RAO has not yet been achieved at the Site, and the operation and maintenance of the remedial system will proceed under Remedy Operation Status. This Remedy Operation Status report has been formatted to reference the requirements for inspection and monitoring reports outlined in section 310 CMR of the Massachusetts Contingency Plan (MCP). 2.0 DESCRIPTION OF INSPECTION AND MONITORING ACTIVITIES (310 CMR (1)) 2.1 Remedial System Monitoring and Inspection The piping, storage tanks, and mixing components of the sodium permanganate system in Building 9 were inspected prior to each permanganate delivery as well as during mixing and injection activities. These inspections included visual inspection of the main permanganate storage tank, the permanganate mixing tank, transfer and injection piping, and the injection and transfer pumping units. Prior to and during injection events at locations remote to the permanganate storage and mixing area (i.e., PSL 10 or Tozer Road South of Route 128), portable permanganate storage containers, hoses and connections were also inspected. Measurements and monitoring data were collected during permanganate injections including the fluid injection rates, injection pressure (where applicable), and the total volume of oxidant injected. The permanganate storage and mixing tanks located in Building 9 are both equipped with high-level sensors connected to an audible alarm to prevent overfilling. The high-level sensors are also connected to a telemetry monitoring system to provide off-site monitoring. The permanganate mixing and storage tanks are located within a containment dike in the event that there is a spill. A sump within the containment dike is also equipped with a liquid level sensor that is connected to the audible alarm and telemetry monitoring systems. These sensors and telemetry systems are regularly inspected for proper operation during remedial activities at the Site.

5 2.2 Monitoring of Physical Parameters in Groundwater The Phase IV Plan proposed detailed monitoring activities for the various treatment areas of the Site. As outlined in the Phase IV Plan, groundwater physical parameters were monitored in select monitoring wells weekly during ongoing permanganate injection activities in the active treatment areas. Once the injection activities were completed for an area, weekly monitoring was completed in select wells for a two-month period after which monthly monitoring continued. Monitoring typically completed during the weekly and monthly events included the following: A visual observation of groundwater color for identification of residual permanganate; Depth to groundwater measurements; and, Measurement of oxidation-reduction potential (ORP), specific conductance, and ph using a down-well water parameter probe. Methodologies for collecting the depth to water and physical parameter measurements are included in Appendix B. 2.3 Groundwater and Surface Water Sampling The Phase IV Plan proposed two groundwater sampling events at approximately three months and nine months following the completion of initial permanganate injection activities. The monitoring schedule was modified to accommodate injection activities that continued later in 2002 than was originally planned due to construction and drilling delays. The first round of post-addition groundwater sampling was conducted approximately two months following the cessation of injection as described below. Additional information regarding groundwater sampling events is presented in Section 4.0 of this report. In January through March 2003, post-addition groundwater sampling was conducted at injection and observation wells throughout the Site. A total of 65 wells were sampled in areas near Building 3, Building 6, 31 Tozer Road, Tozer Road North of Route 128 and Tozer Road South of Route 128. Groundwater samples were not collected from several wells (i.e., AP15-S, CL9-BR, or MW-4R) due to lack of accessibility from ice and snow buildup. Groundwater samples were not collected from the PSL 10 treatment area since permanganate injections continued in that portion of the Site through February 2003; sampling in that area is scheduled for May Well locations are shown on Figure 2. The groundwater VOC sampling conducted during this monitoring period utilized passive diffusion bag (PDB) samplers, with the exception of monitoring wells BR-5 and MW-3R, where alternative methods were used as discussed below. The PDBs were deployed in the monitoring wells on January 10 through January 13, 2003 and collected following a minimum two-week equilibration period. Procedures for deployment and sampling of the PDB samplers are provided in Appendix B.

6 During sample retrieval in late January 2003, eight sample bags were either lost or damaged during the equilibration period. Replacement PDB samplers were deployed on February 3, 2003 for the following wells: OB5-S, RW-1, RW-2, RW-3, RW-17, AP-2, AP12-S, and AP14-S. The redeployed PDB samplers were collected and submitted for laboratory analysis on February 17 and 20, Alternative methods of groundwater sampling were conducted for wells BR-5 and MW-3R. Bedrock well BR-5 was constructed using a packer system to allow three separate zones for sampling. This well is sampled using a Waterloo system, which utilizes dedicated dual-valve pumps driven by compressed nitrogen. As a replacement for the inaccessible well MW-4R, observation well MW-3R was sampled on March 5, This well is within 60 feet of MW-4R and is screened in the same zone. Sampling was conducted using a conventional bailing method in order to maintain a close timeframe with other Site sampling data rather than the longer turnaround for the PDB deployment. Detailed procedures for purging and sample collection are included in Appendix B. Each well, with the exception of BR-5, was also sampled with a conventional bailer for the collection of groundwater for analysis of dissolved metals (manganese and iron) and chloride, constituents which cannot be collected using the PDB samplers. Groundwater from injection wells and select monitoring wells was also collected for permanganate concentration analysis. Each of the dissolved metals and permanganate concentration samples were field filtered using a 0.45-micron filter. As requested by the Beverly Conservation Commission, surface water samples for analysis of dissolved manganese were collected from the Unnamed Stream at locations STRMH-2 and STRHA-3. The groundwater and surface water samples were submitted to Eastern Analytical Laboratories, Inc. of Concord, New Hampshire for analysis of VOCs by EPA Method 8021, dissolved iron and manganese, and chloride. The samples collected for colorimetric analysis of residual permanganate were analyzed by Shaw using a Hach DR/890 colorimeter. The colorimeter utilizes spectrophotometric methods to determine the permanganate concentration based on a known permanganate concentration calibration standard. Methodology for the permanganate concentration analysis is presented in Appendix B. 3.0 RESULTS OF INSPECTION AND MONITORING ACTIVITIES (310CMR (5)) 3.1 System Monitoring and Inspection Results The piping, tank storage and mixing components of the sodium permanganate system located in Building 9 were determined to be of sound integrity during this reporting period. No failures of primary system components occurred during the system operation. The portable permanganate storage containers, hoses and connections used for remote applications were also inspected during each use and were found to be in working order.

7 Late in 2002, computer problems impacted remote instrument monitoring capabilities. The computer issues did not allow remote monitoring of the tank volumes; however, chemical deliveries and tank transfers were carefully observed and volumes calculated by on-site personnel. No liquid permanganate was stored in the system over the winter. Improvements to the remote monitoring system will be completed prior to 2003 injection activities. Total fluid addition volumes for injection wells during the initial 2002 remedial period are presented on Table 1. The total fluid volumes for the PSL 10 treatment area include the additions made during January and February Groundwater Physical Parameter Results During this reporting period, measurements of ph, specific conductance and ORP were recorded periodically in select wells according to the monitoring schedule presented in the Phase IV Plan. Results of water quality parameter measurements collected from monitoring wells during 2002 and 2003 are presented in Appendix C. Physical parameter monitoring was conducted in each area during this reporting period based on the following schedules: PSL 10: weekly physical parameter monitoring of area wells began once the permanganate injections were initiated in November Weekly monitoring was performed throughout the permanganate injection period (November 2002 February 2003). Weekly parameter monitoring continued through March 2003 and will be conducted monthly beginning April Building 3 Area: Weekly monitoring was performed during the permanganate injection period, which ended during November The weekly monitoring continued into February 2003 when a monthly monitoring schedule was initiated. Building 6 Area: Weekly monitoring was performed during the permanganate injection period, which ended during December The weekly monitoring continued through February 2003 when a monthly monitoring schedule was initiated. Tozer Road South of Route 128 Area: Weekly monitoring was performed throughout the permanganate injection period, which ceased in November Weekly monitoring continued through January 2003, when a monthly monitoring schedule was initiated.

8 Physical parameter measurements collected during 2002 and 2003 have been summarized as follows: Groundwater ph measurements ranged from 0.83 at well OB16-S on January 14, 2003, to at well OB16-BR on February 3, The low reading of 0.83 detected at well OB16-S on January 14, 2003 is likely an instrument error since all historical readings from this well have ranged from approximately 6 to 10. Additionally, monitoring of ph in well OB16-S the weeks prior to and following the measurement of 0.83 indicated ph readings of 6.94 and 6.31, respectively. The elevated ph readings that were inconsistent with other readings at the Site were observed in recently installed deep overburden or bedrock wells and likely influenced by well construction materials (i.e., cement grout) and the fact that no groundwater purging was associated with sampling using passive diffusive bag samplers. Cement grouts typically have a ph greater than 12 and is likely the source of the elevated readings in the wells. The average of ph readings collected at the Site from June 2002 through March 2003 is 7.38 and indicates a groundwater ph value within the normal historical range. Specific conductance in groundwater was measured and ranged from siemens per meter (s/m) at well MW-5 on August 15, 2002 to s/m at well OB16-BR on November 27, The average of the specific conductance readings from across the Site collected from June 2002 through March 2003 was s/m. Specific conductivity readings may be affected by environmental factors, including total dissolved solids (road salt), and may not necessarily reflect influence from permanganate injections. Dissolved components affecting the specific conductivity during permanganate injection and treatment may include chloride, magnesium, and sodium. Typically, the higher the content of dissolved solids, the higher the specific conductance measurement. The specific conductance measurements have not been used in evaluations of the remedial treatment at the Site at this time due to the variables involved; however, since this data is recorded simultaneously from the same instrument used to monitor ph and ORP, the data was tabulated and reported for use in long-term observations. Groundwater ORP readings ranged from negative (-) 474 millivolts (mv), indicating a reducing environment, at monitoring well OB23-BR on June 3, 2002 to 690 mv (indicative of oxidizing conditions) at well OB4-S on October 22, The high ORP reading at well OB4-S on October 22, 2002 is attributed to an instrument or data recording error as values of that magnitude are consistent with the presence of unreacted permanganate (>500 mv), but no permanganate was ever observed in well OB4-S. The average of ORP readings collected from June 2002 through March 2003 was ORP values at monitoring wells not receiving permanganate injections showed a significant increase during the permanganate addition period, with a slow return toward baseline conditions as the permanganate was consumed in the VOC remedial treatment process. Generally, the results indicated that permanganate treatment influenced monitoring points more quickly and at greater distance from the injection source than initially expected. Other than the volume of permanganate additions, characteristics that will affect the lateral effect of permanganate oxidation include the matrix demand, matrix permeability and the groundwater gradient.

9 3.3 Groundwater and Surface Water Analytical Sampling Results Post permanganate addition groundwater and surface water sampling was conducted from January through March 2003, at injection and observation wells and stream locations in the areas of Building 3, Building 6, 31 Tozer road, Tozer Road North of Route 128 and Tozer Road South of Route 128. Analytical results of target VOC compounds tetrachloroethene (PCE), trichloroethene (TCE), and cis-1, 2- dichloroethene (DCE) from groundwater samples collected during the baseline and post-addition sampling events are presented on three Site maps (Figures 3, 4 and 5). Figure 3 depicts groundwater data from shallow overburden wells, Figure 4 depicts groundwater data from deep overburden wells, and Figure 5 depicts groundwater data from bedrock wells. The results of the baseline and post addition VOC analytical data are summarized on Table 2. The complete laboratory analytical reports are provided in Appendix D. A qualitative discussion of the sampling results is presented below based on the one round of postaddition sampling data collected in January through March 2003, and compared with the baseline groundwater data collected in June As more analytical data are collected, (e.g., May 2003) a more comprehensive discussion and evaluation of concentration trends will be presented in subsequent status reports. The initial monitoring results show a marked decrease in target VOC compounds in many wells at various depths and distances from injection points, indicating that the injection program has begun to achieve the remedial objectives. The results of the shallow aquifer sampling generally indicate reduced or similar concentrations of the target VOC compounds in the majority of the shallow wells across the Site. Significant decreases were observed, for example, at well AP14-S (adjacent to Building 3) where PCE levels decreased from 39 parts per million (ppm) in June 2002 to below the detection limit in February Similar significant reductions were measured at AP12-S (adjacent to Building 6) where TCE levels decreased from 7.2 ppm to below the method detection limit. Target compound increases in the shallow aquifer were noted in some wells east of the Building 6 treatment area but with much lesser magnitude than the target VOC compound increases. The target VOC increases were noted in wells OB15-S (DCE ppm to 3.8 ppm), MW-9 (TCE 2.2 ppm to 13 ppm, DCE 0.62 ppm to 1.3 ppm), MW-9A (TCE ppm to 1.6 ppm, and DCE 0.13 ppm to 2.6 ppm), and OB10-S (DCE below the detection limit to 1.2 ppm). These increased concentrations are likely the result of a combination of the desorption of VOCs from soils (as a result of the interactions between permanganate and natural organic materials) and the shutdown of the pumping system (the pumping system was deactivated in May 2002, shortly before the baseline sampling in June 2002). However, the recent concentrations remain less than historic maximum concentrations from samples collected from this vicinity before and during the first several years of the pumping system operation. Results of the shallow overburden aquifer data are posted on Figure 3.

10 The results of the deep overburden aquifer VOC data generally indicate reduced concentrations of the target compounds in most of the deep overburden wells across the Site as compared with baseline concentrations. Significant VOC concentration reductions were observed in the area of Buildings 3 and 6, for example, at wells CL5-DOA (TCE decreased from 200 ppm to below the detection limit (BDL)), OB19- DO (TCE decreased from 210 ppm to ppm) and RW-2 (PCE decreased from 9.1 ppm to ppm). Deep overburden groundwater target VOC reductions were also prevalent downgradient from the source area at Tozer road south of Route 128 area, including well CL3-DO (PCE 4.5 ppm to BDL, TCE 30 ppm to BDL, and DCE 12 ppm to BDL). Increases of deep overburden aquifer target compounds were noted at a much lesser magnitude than the cited decreases in the Building 3 treatment area and east of the Building 6 treatment area for compounds including wells OB12-DO (DCE 4 ppm to 91ppm), AP13-DO (PCE 9.5 ppm to 64 ppm and TCE 110 ppm to 430 ppm), and OB9-DO (DCE 3.2 ppm to 9.7 ppm). Although increased concentrations of some of the individual compounds (primarily DCE) were identified, it should be noted that concentrations of other compounds decreased to the point that total VOC concentrations were reduced for all of these wells except AP13-DO, including well OB12-DO (PCE 2 ppm to 0.4 ppm and TCE 120 ppm to 33 ppm). Increased VOC concentrations in the wells can be attributed to a combination of desorption of VOCs from soils (DCE desorbs more readily than the other compounds) and the shutdown of the pumping system (May 2002). Results of the deep overburden aquifer data are posted on Figure 4. The results of the bedrock aquifer VOC data generally indicate reduced concentrations of the target compounds in most of the bedrock wells across the Site. Significant VOC concentration reductions were observed in the Building 6 area, for example, at wells OB9-BR (TCE decreased from 9.2 ppm to 0.1 ppm), AP12-BR (DCE decreased from 4.7 ppm to below the detection limit) and RW-17 (PCE decreased from 4.9 ppm to ppm). Bedrock groundwater target VOC reductions were also evident downgradient from the source area at Tozer road south of Route 128 area, including well RW-19 (PCE 6.5 ppm to BDL, TCE 37 ppm to BDL, and DCE 25 ppm to BDL). An increase of DCE was noted in the Building 3 treatment area and east of the Building 6 treatment area in wells OB12-BR (1.5 ppm to 8.7 ppm), and OB9-BR (1.6 ppm to 7.1 ppm). However, total VOC concentrations in well OB9-BR decreased including target compounds PCE (39 ppm to 0.05 ppm) and TCE (9.2 ppm to 0.01 ppm). Results of the bedrock aquifer data are posted on Figure 5. Increases in groundwater chloride concentrations in areas where permanganate addition was completed further support that the destruction of VOCs has occurred. For example, chloride concentrations increased from 80 ppm to 200 ppm at well AP14-S, from 70.8 ppm to 330 ppm at well CL5-DOA and from 70.4 ppm to 400 ppm at well AP12-BR. Each of these well locations also saw significant reductions in VOC concentrations. Results of chloride sampling are included on Table 3 and complete laboratory analytical reports are provided in Appendix D. Groundwater concentrations of dissolved iron in monitoring wells across the Site were varied. Typically the dissolved concentrations should decrease in the treatment areas due to the oxidizing nature of permanganate precipitating the metals from the groundwater. Dissolved manganese concentrations also

11 varied across the Site. High concentrations were noted where un-reacted permanganate was observed during the post-addition sampling period. Dissolved manganese samples were also collected from two stream locations following the permanganate additions. However, the dissolved manganese results were generally within the normal observed range, although no previous Site samples were available for comparison. Groundwater and surface water dissolved metal data are summarized on Table 3. The complete laboratory analytical reports are provided in Appendix D. During the post-injection sampling event, additional groundwater samples were collected from injection wells and select monitoring wells and analyzed for permanganate concentrations through colorimetric analysis. The main purpose of this sampling was to establish areas where residual permanganate levels were greatest; this data was used to help evaluate where treatment during 2003 should be directed. Generally, permanganate is visible at concentrations of one milligram per liter, or one ppm (0.0001%) and greater. Results of the colorimetric testing indicated that several of the injection wells continued to contain permanganate (>1 ppm). Permanganate concentrations ranged from non-detectable levels in several monitoring and addition points to 79,477 ppm (~8%) in well RW-2. As a comparison, permanganate was added to RW-2 and other injection wells at a concentration of approximately 200,000 ppm (20%). Results of the colorimetric analyses are presented on Table SIGNIFICANT MODIFICATIONS TO THE INSPECTION AND MONITORING PROGRAM (310 CMR (2)) Modifications were made to the Phase IV Plan based on Site conditions, initial monitoring results, and other project circumstances. This section summarizes the minor changes and proposed modifications from the December 2001 Phase IV Plan. The 2001 Phase IV Plan outlined a groundwater monitoring schedule for both the collection of groundwater physical parameter measurements as well as groundwater analytical sampling. According to the Plan, during the permanganate additions, physical parameter monitoring was to be conducted at selected wells and stream locations either monthly or weekly, depending on the monitoring well location in relation to surface water in the area. Post addition monitoring was proposed for a weekly schedule for the first two months, then to a monthly basis. The Phase IV Plan proposed sample collection for laboratory analysis to be conducted three months and nine months following the cessation of permanganate additions. During the 2002 injection activities, changes to the physical parameter monitoring included an increase in the number of wells being monitored. Generally, wells within the vicinity of the injection points were monitored weekly throughout the addition and two month post-addition periods until changing to the monthly schedule. Changes were also made to the analytical monitoring schedule proposed in the Phase IV Plan, as injection activities continued later in 2002 than originally scheduled in the Phase IV Plan. Post-addition sampling was conducted approximately two months following the cessation of the 2002 permanganate

12 additions, sooner than the three months proposed in the Phase IV Plan. The second post-addition sampling event has been scheduled for about five months after the cessation of permanganate additions, and will be conducted in May The analytical sampling periods were accelerated in order to obtain and evaluate analytical results of VOCs in groundwater in a time frame that allows for effective planning of the 2003 injection program. 5.0 DESCRIPTION OF PROBLEMS AFFECTING THE PERFORMANCE OF THE REMEDIAL ACTION (310 CMR (3)) There were no significant problems encountered during this reporting period that affected the performance of the remedial action. 6.0 MEASURES TAKEN TO ADDRESS PROBLEMS AFFECTING THE PERFORMANCE OF THE REMEDIAL ACTION (310 CMR (4)) There were no corrective measures necessary to affect the performance of the remedial action. As discussed below, a number of minor modifications are planned to optimize the continuing remedial actions. 7.0 MODIFICATIONS TO THE REMEDIAL ACTION (310 CMR (3)) A number of minor modifications are planned to the Phase IV Plan based on site conditions, monitoring results and other project circumstances. This section summarizes the current changes and proposed modifications from the December 2001 Phase IV Plan that have not been previously presented in the Phase IV Completion Report. The following list summarizes modifications to the Phase IV Plan which are described in more detail in following sections: Activities in the Longview/Hill Street continue to be on hold Injection plans at the Tozer Road area South of Route 128 were modified Injection points west of the Building 3 and 6 treatment areas were added Additional observation and injection wells were planned Injection volumes of permanganate were revised Shallow permanganate injection at PSL 10 was modified Injection plan developed for 31 Tozer Road area

13 7.1 Longview/Hill Street Area Property access agreement negotiations continue for this portion of the Site. Because access has not yet been obtained, well installation activities in the Longview/Hill Street treatment area have not been initiated and the proposed treatment in this area is currently on hold. Since a Condition of No Significant Risk already exists in this area, the performance of treatment at this location is not expected to be necessary for Varian to achieve a Permanent Solution at the Site under the MCP. 7.2 Tozer Road South of Route 128 The Phase IV Plan identified two deep overburden aquifer wells, MW-36 and CL3-DO, to receive permanganate during 2002 and However, low VOC groundwater concentrations in samples collected in June 2002 and January 2003 revealed that permanganate applications to MW-36 were not necessary. Permanganate addition to the deep overburden aquifer in the area of Tozer Road south of Route 128 was conducted at well CL3-DO during 2002, but due to low VOC concentrations detected in January 2003, further injections to the deep overburden in this area will not be continued in 2003 unless significant rebound is observed during the May 2003 sampling event. 7.3 Additional Injection Points West of the Building 3 and 6 Treatment Areas Monitoring wells OB19-DO and OB19-BR were utilized as injection points during the 2002 injection program in order to treat the deep overburden and the bedrock aquifers west, and hydraulically downgradient of the Building 3 and 6 source areas, as elevated VOC concentrations were revealed during the baseline sampling event at these new wells. These wells have been selected for permanganate additional again during the 2003 activities. 7.4 Proposed Additional Injection and Monitoring Well Installations An evaluation of the post-injection VOC data indicated that groundwater at certain locations and depths in the Building 3 and Building 6 areas may benefit from increased permanganate injection in these areas. Elevated groundwater VOC concentrations detected in the OB19-DO/OB19-BR couplet during the baseline monitoring event indicated a potential demand for oxidant treatment. Permanganate additions in 2002 to the OB-19 deep overburden and bedrock well couplet, located west of the Building 3 and 6 source areas, were determined to have a positive, although limited impact. The low transmissivity of the deep overburden and bedrock wells limited the injection quantities and the ability to treat this area, as indicated by low residual permanganate in those wells. Therefore, the installation of two additional deep overburden and bedrock well couplets, one north and one south of the OB19 couplet, is proposed to treat adjacent cross-gradient impacted areas and help delineate the extent of VOC impacts at this location of

14 the Site. Additionally, a third deep overburden and bedrock well couplet is proposed further west of the OB19 well couplet, to be used as an additional downgradient monitoring point. Post-addition groundwater samples from the shallow aquifer east of the Building 3 and 6 treatment areas near the Unnamed Stream revealed increased VOC concentrations above the baseline sampling results, although still below historic high results. To address this increase, ten (10) shallow aquifer injection wells are proposed for installation between the main Building 3 and 6 treatment areas and the existing shallow wells along the Unnamed Stream bank. Proposed treatment in the new wells will consist of small doses of permanganate, administered periodically for the purpose of acting as a treatment zone for VOC impacted groundwater flowing toward the east. 7.5 Revised Permanganate Volumes As presented in the Phase IV Plan, the dosage of permanganate for the various treatment areas was calculated based on groundwater VOC concentrations and estimates of soil oxidant demand. However, during the 2002 injection period, injection volumes were adjusted based on the hydraulic transmissivity of individual wells and their associated ability to receive permanganate. Injection volumes planned for 2003 have been similarly adjusted and were also refined following evaluation of the results of the post-injection VOC data by noting the successful influence that the injections were having on the local areas and downgradient monitoring locations. Proposed injection volumes were revised for the Building 3, Building 6, PSL 10, and the Tozer Road South of Route 128 treatment areas. Results of the revised permanganate volume calculations are summarized and compared to the estimates included in the Phase IV Plan in Table 1. Overall, the Site-wide planned volume of 2003 permanganate additions decreased when compared with the planned estimates provided in the Phase IV Plan, from approximately 86,700 gallons to 58,200 gallons of 20% sodium permanganate solution. Interpretation of the VOC results from the May 2003 monitoring event may further influence proposed injection quantities. 7.6 PSL 10 Treatment Area Modification Permanganate additions to the PSL 10 area were initiated in November The injection wells at this area could not accept permanganate at rates anticipated in the Phase IV Plan. Low volume permanganate additions to the PSL 10 wells were continued concurrently with other tasks at the Site until February 2003; when the tasks at other locations of the Site were completed, permanganate additions to the PSL 10 area were discontinued. The injection plan for permanganate addition in the PSL 10 area during 2003 will be determined after evaluation of the May 2003 sampling data. Based on the limited permanganate volume that was added from November 2002 through February 2003, the volume of permanganate to be added in the remainder of 2003 will likely be small and be conducted concurrent with other activities at the Site.

15 A Condition of No Significant Risk already exists in the PSL 10 area. Therefore, reducing or discontinuing further treatment of this location would not preclude Varian s ability to achieve a Permanent Solution at the Site under the MCP Tozer Road Area Based upon the results of the 2002 shallow overburden trial injection at 31 Tozer Road and the anticipated beneficial downgradient impacts to deep overburden groundwater quality from the 2002 injections in the Tozer Road South of Route 128 area, the proposed 2003 injection plans for 31 Tozer Road have been modified. Additional adjustments may also be made upon evaluation of the May 2003 groundwater VOC data. Presently, proposed activities for 31 Tozer Road area include a trial injection into the deep overburden at a new location to assess downgradient VOC reduction and radius of influence. Additionally, a shallow overburden injection event is planned, similar in quantity to that performed in The locations of the shallow and deep overburden injections have not been finalized and will be determined upon agreement with the property owner. The projected injection amounts are presented in Table CONCLUSIONS As described in the preceding sections, remedial activities are in progress at the former Varian Facility Site in general accordance with the Phase IV Remedy Implementation Plan (IT, 2001). Minor modifications to the in situ oxidation treatment program are being made based on Site conditions, monitoring data, and recent sampling results as discussed in this status report. The initial groundwater VOC analytical results show a significant decrease in target VOC compounds in many wells at various depths and distances from injection points indicating that the injection program has begun to achieve the remedial objectives. Additional permanganate injection will be performed in 2003 and continued remedial progress will be reported in the next six-month status report. 9.0 REFERENCES IT, 2001, Phase IV Remedy Implementation Plan Former Varian Facility Site, 150 Sohier Road, Beverly, Massachusetts, December Shaw, 2002, Phase IV As-Built Construction And Final Inspection Report, Former Varian Facility Site, 150 Sohier Road, Beverly, Massachusetts, October 2002