Draft Site-Specific Radiological Survey Plan

Home , Shpack Landfill

Supci -fund Rccoids Cutler SITE: BREAK: 2.£ OTHtK:

EPA Contract No. 68-W6-0042 EPA Work Assignment No. 049-RSBD-0129

EPA Project Officer: Diana King EPA Remedial Project Manager: Dave Lederer

DRAFT SITE-SPECIFIC RADIOLOGICAL SURVEY PLAN

Shpack Landfill Superfund Site Norton, Massachusetts

January 2000

Prepared by: Metcalf & Eddy, Inc. 30 Harvard Mill Square Wakefield, Massachusetts 01880 ex

A i i i A * i ,« i- Superfund Record* Center ALLIANCE SITE: BREAK: J-020663-0001 OTHER: ,

January 14, 2000

Mr. David O. Lederer Remedial Project Manager U.S. EPA Region 1 1 Congress Street Suite 11 00 (HBO) Boston, MA 02114

Subject: Contract No. 68-W6-0042 Work Assignment No. 049-RSBD-0129 Shpack Landfill Superfund Site Draft Site-Specific Radiological Survey

Dear Mr. Lederer:

Enclosed please find two copies of the M&E Site-Specific Radiological Survey Plan as part of the oversight of Potentially Responsible Party Remedial Investigation/Feasibility Study activities at the Shpack Landfill Superfund Site, located in Norton, MA.

Very truly yours,

METCALF & EDDY, INC.

^u Edward A. Conroy, P.E/ Work Assignment Manager

enclosures:

cc: D. King, EPA (cover letter only) C. Hagger, M&E (cover letter only) H. Hickman, M&E R. Renzi, M&E Contract File WA #049-RSBD-0129

Aqua Alliance Inc. „„ ,, . , ..., „ an affiliate of 30 Harvard Mill Square P.O. Box 4071 Wakefield, MA 01880-5371 Tel: 781 246 5200 Fax: 781 245 6293 TABLE OF CONTENTS

EXECUTIVE SUMMARY ES-1

1.0 INTRODUCTION 1 1.1 Site Description 1 1.2 Site Background 3 1.2.1 ORNL 1980 Survey 3 1.2.2 Enriched Uranium Removal-Post ORNL Survey 7 1.2.3 Bechtel/Eberline 1982 Survey 7

2.0 PURPOSE AND SCOPE 12 2.1 Characterization of Radiological Contamination 12 2.2 Survey Data Validity 12

3.0 GENERAL APPROACH 13 3.1 Radiological Contaminants of Concern 13 3.2 Guidance Documents 14 3.3 Data Quality Objectives 14

4.0 SURVEY OBJECTIVES 16 4.1 Classification of Areas 16 4.2 Consistency with Fast Survey 16 4.3 Site Background Radioactivity 16

5.0 FIELD SURVEY ACTIVITIES 17 5.1 Pre-Survey Activities 17 5.2 Surface Gamma Scan 17 5.3 Surface Soil Samples 19 5.4 Additional Boreholes 19 5.5 Groundwater Samples 22 5.6 Surface Water and Sediment Samples 22

6.0 CONTRACTOR ORGANIZATION AND RESPONSIBILITIES 26 6.1 Quality Assurance Project Plan 26 6.2 Data Assessment 26 6.3 Waste Handling 26

7.0 REFERENCES 27

FIGURES: Figure 1. Shpack Landfill Superfund Site - Location Map Figure 2. Shpack Landfill Fenced Area and Grid Figure 3. Shpack Landfill - Proposed Additional Boreholes Figure 4. Shpack Landfill - Proposed Surface Water Sample Locations Figure 5. Shpack Landfill - Proposed Sediment Sample Locations EXECUTIVE SUMMARY

The Shpack Landfill in Norton and Attleboro, Massachusetts was found to be contaminated with both chemical and radiological contamination in the late 1970s. The site was investigated by the Nuclear Regulatory Commission and then surveyed by units of the Oak Ridge National Laboratory in 1980 and Department of Energy contractor Bechtel National, Inc., and subcontractor Eberline Instrument Corporation in 1982. The condition of the landfill was considered stable, and it has remained largely unchanged in the interim since 1982.

In the interest of moving forward with site cleanup, it is necessary to perform a survey to complete the radiological characterization of the site. The results of this survey, together with existing data from the 1980 and 1982 surveys, will provide for evaluation of remedial and cleanup alternatives.

Consistent v. 'th the latest Agency guidance, the survey will be carried out by an organization qualified and experienced in such surveys, which will have Standard Operating Procedures covering much of the survey activities, and an existing Quality Assurance/Quality Control program. The contractor will prepare and submit for Agency review quality assurance documents appropriate for the survey as well as its Standard Operating Procedures that will be used.

Accordingly, this Plan is structured to a large degree to summarize the existing status of radiological contamination characterization and identify needs and objectives for the survey. 1.0 INTRODUCTION

This document is a plan for a Site-Specific Radiological Survey of the Shpack Landfill site in Norton and Attleboro, in southeastern Massachusetts. The site was surveyed extensively for radioactivity in the early 1980s by units of the Oak Ridge National Laboratory (ORNL) and Department of Energy (DOE) contractor Bechtel National, Inc. (BNI), and subcontractor Eberline Instrument Corporation (EIC). The Shpack Landfill was placed on the National Priorities List (NPL) in 1986 and is slated for remediation under the Formerly Utilized Sites Remedial Action Program (FUSRAP). This Plan was prepared under Work Assignment No. 049-RSBD-0129 under the U.S. Environmental Protection Agency (EPA) Response Action Contract (RAC) to provide oversight of Potentially Responsible Party (PRP) RI/FS activities at the Shpack Landfill Superfund Site.

1.1 Site Description. The site is a landfill made by filling in a swamp or deep-water wetlands. It is nearly flat, with minor depressions and knells. A permanent pond lies at the eastern (northeastern) border. At least two other low areas also normally contain standing water normally. Other low areas support wetland vegetation. The surface generally is covered with grass, shrubs, and trees, but metal including drums and construction/demolition debris and plastics are visible.

The landfill was reportedly filled from the road in a southeast direction to its termination at Chartley Swamp.

Areas to the east and north of the site are low wetland areas also. To the south is the larger Attleboro landfill (ALI), which was also created by filling with waste materials in former wetland areas, rising approximately 100 feet above the surrounding ground surface. West of the site, the area is flat, with Chartley Brook beyond. To the northwest (across Union Road and Peckham Street), to the southeast, and northeast are undeveloped areas. An eight-foot high fence was erected to include the limits of radiological contamination. The fenced area is also roughly the limit of landfill material except at the southeast corner. Three sets of power transmission lines traverse the area. (See Figure 1.)

1 JiHFACK. LAN Ul ILL SI 1 fc|

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REFERENCE NORTON, M V QUADRANGLE USGS TOPOGRAPHIC MAP, 1964

FIGURE 1. SHPACK LANDFILL SUPERFUND SITE - LOCATION MAP 1.2 Site Background. The Shpack Landfill operated as a domestic and industrial landfill from about 1946 to 1965 when it was closed by a court order. It consists of approximately eight acres, including land formerly owned by Lea and Isadore Shpack who lived there and land formerly owned by Albert Dumont. The Norton/Attleboro tcwn boundary line crosses the landfill. The land was originally a swamp, and the landfill was developpH V>y progressive filling of a portion of the swamp with wastes, starting along the Union Road and Peckham Street, proceeding to fill in a southeast direction to the present Chartley Swamp.

In the late 1970s, the Nuclear Regulatory Commission (NRC) investigated reports of materials in the landfill that were believed to be or known to be radioactive. Following its initial investigation, the NRC performed survey work in late 1978 together with the Commonwealth of Massachusetts, Department of Public Health. The NRC concluded that "substantial quantities" of depleted uranium were present in the landfill along with much smaller quantities of enriched uranium and minor quantities of radium-226 that are sometimes separate from the uranium contamination. Presence of uranium-236 in all samples tested confirmed that the source was recycled nuclear reactor fuel.

1,2.1 ORNL 1980 Survey. After me initial findings of me NRC, a further survey was performed in August through October 1980, by the ORNL Health and Safety Research Division.

In the ORNL survey (1980), a grid was established. (See Figure 2.) Beta gamma dose rates at one centimeter and external gamma radiation levels at the surface and at one meter from the surface were taken at locations throughout the site. Surface samples were taken at grid centers and in locations biased by instrument readings, analyzed for radium-226, uranium-238, uranium-235. Subsurface samples were taken in boreholes drilled until water was encountered, usually one to six feet. These boreholes were gamma-logged by means of a sodium iodide crystal (Nal) probe lowered inside a 4" plastic pipe, encased in lead shield with horizontal row of "collimating slits".

Samples were designated for analysis based on the gamma logging. Continuous cores were collected (attempted) at some locations; however, ORNL reported "difficulty driving the sampler through rubble and debris," and "recovery rate of cored material was extremely low."

Water samples from these boreholes were analyzed for radium-226, uranium-238, uranium-235, thorium-230, and lead-210. These were considered ground water, but it does not seem clear whether radionuclides in these borehole water samples were from ground water or from the soil through which they were bored or sidewalls of boreholes. Surface samples were taken from the swamp adjacent to the site and from ponds and streams that received drainage from the site. These were analyzed for the same radionuclides as were the borehole water samples.

Radionuclide and elemental analysis was performed on debris samples collected from the site.

ORNL made "background" measurements of external gamma at one meter above ground at distances between 100 feet and 1 mi'ie from the site at points SW, NE, NW, and SE. Ranged from 4 to 9 microR/h with an average of 7 microR/h. Soil samples at those same locations showed 0.64 pCi/g of radium~226 and 0.66 pCi/g of uranium-238. Background beta-gamma dose rates were done with a G-M survey meter, averaged approximately 0.02 mrad/h ~ not reproducible. ORNL attached little significance to variations in measurements at or near the background average.

Radium-226 in "systematic" samples ranged from less than 1 to 11 pCi/g. As high as 47,000 pCi/g were seen in biased samples. Eight of 72 "systematic soil samples" (from the centers of grid blocks) were above background for radium-226. In debris samples where Ra-226 was primary, radioactivity was associated with small rings or hemispherical glass beads set in metal holders.

Uranium-238 in systematic soil samples ranged from 1 to 140 pCi/g. The maximum from a biased soil sample was 96,300 pCi/g. Uranium-235 ranged 0.03 to 51 pCi/g in systematic soil samples, and from 0.47 to 7080 pCi/g in biased soil samples. Two thirds of the surface soil samples were subjected to isotope dilution mass spectrometry; depleted, natural, and enriched uranium all were found. Enrichment as high as 76% was found. Of 63 samples, 5 were depleted, 21 were natural uranium, and 37 were enriched. Sixteen soil samples were selected for uranium-236 determination and all contained "significant" uranium-236, ranging from 0.0043% to 0.293%.

Auger holes were "gamma logged" using tnc scintillation detector. This method is not nuclide specific. A micro-Curie of one nuclide will not produce the same response as a micro-Curie of another, so concentration of radionuclides in soil could not be reliably estimated from the logging. Comparing logging data to soil analyses, it appeared to ORNL that a reading of 1.000 counts per minute (CPM) or greater indicated the presence of "elevated" concentrations of Ra-226 and/or uranium. So for the ORNL survey, a reading greater than 1,000 CPM in the gamma logging or a soil analysis >5 pCi/g either Ra or total U, was considered as contaminated. ORNL concluded that because of the difficulty detecting uranium with the shielded scintillator, subsurface concentrations "considerably in excess of 5 pCi/g may have gone undetected, in the absence of radium-226."

Three "ground water" samples from boreholes exceeded the NRC concentration guidelines from 10 CFR Part 20 for radium-226. None exceeded those guidelines for uranium, thorium-230, or lead-210. Up to 4,400 pCi/L of uranium-238 and 2,400 pCi/L of uranium-235 was in water taken from boreholes. The maximum for radium 226 was l,400pCi/L.

Surface water samples from the swamp were below the 10 CFR Part 20 Appendix VI CGw, but above background levels of near 1 pCi/g of uranium-238 and 0.04 pCi/g of uranium-235.

The higher gamma readings in this survey were typically far higher at the surface than 3 feet above, including on the Attleboro Landfill side. These were points showing maximum gamma readings within blocks. The finding of much higher readings at the surface is indicative of localized sources on the surface or slightly below the surface. The ORNL survey generally located the contamination on-site and characterized the range of concentrations found and the fact that it was very heterogeneous and "spotty" in distribution. The survey did not establish the areal extent or depth of

co~'—;r,a*; _ T-se ?0:j jjata sti]j v,ave some value, though the water sampling data probably du not.

1.2.2 Enriched Uranium Removal Post-ORNL Survey. Very sketchy records revealed that enriched uranium was removed from the Shpack landfill site immediately after the ORNL survey. The record consisted of a 1988 Record of Telephone Conversation of BNI with EIC, two U.S. Department of Energy Contractors who were becoming active at the Shpack Landfill site. The record indicated that 800 to 900 pounds of uranium metal fragments enriched in uranium 235 were removed from the Shpack Landfill site under armed guard immediately following the ORNL (1980) investigation, and transported to ORNL for retention. This action would apparently have been taken to satisfy legal requirements for the safekeeping of enriched uranium. This record implies that radiation instruments were used to locate metal fragments on the surface or very close to the surface, for removal. This record accounts for the fact that instrument readings reported from the site early were far higher than those seen in later survey activities.

1.2.3 Bechtel/Eberline 1982 Survey. The ORNL survey (August-October 1980) confirmed the NRC's preliminary finding that radium and uranium were the principal contaminants and defined the general areas of contamination. Based on those results, the Shpack Landfill was designated by DOE as a candidate site for remedial action under FUSRAP in 1981.

One principal observation from the ORNL survey was the spotty or non-uniform d'v+':u"t:on of r"dioactive material on the site. Additional survey data on the depth of contamination and on the size and shape of the contaminated areas were required to provide input to FUSRAP for an engineering evaluation of possible remedial action alternatives. To that end, the BNI and instrument subcontractor EIC performed a survey two years later than the ORNL survey, in August and September 1982. The objective was to provide a definitive description of the boundaries of contamination. Although discrete items of enriched uranium had been removed as mentioned above, BNI/EIC considered that no actions had occurred at the site to change contamination patterns in environmental media. Accordingly, the BNI/EIC study was considered a follow-on to the ORNL survey.

The grid from the ORNL survey was re-established. Beta-gamma measurements used a thin-window Geiger-Mueller probe EIC HP-210 detector, which (like the ORNL instrument) gave a background of 0.02 mrad/hour.

Gamma measurements were taken one foot above ground using a 2-inch sodium- iodide detector (Eberline Instrument Corporation SPA-3). A conical lead shield was used for downward directional response. "Average background reading" for this instrument in the landfill area was 5,000 CPM. "Counts per minute" is an instrument- specific term that cannot be converted into a radiation or dose measurement without calibration to the specific radionuclides of interest. Readings were made at 20 ft intervals within the grid, then additional readings were taken as deemed necessary at 5 ft intervals (based on the ORNL report) to define more precisely the boundaries of contaminated surface soil.

Gamma levels at 3 ft were taken on the grid points at 100-ft intervals with an instrument utilizing the two-inch cube sodium iodide detector (EIC SPA-3). A pressurized ionization chamber instrument (PIC) was used to make a series of measurements to obtain a calibration factor for the gamma readings that were taken with the EIC SPA-3. With the calibration factor, an actual gamma radiation level in microRoentgens per hour could be obtained from the counts-per-minute output of the SPA-3. (The heavier, more unwieldy ionization chamber instrument gives an output proportional to actual ionization, and thus can be used to calibrate the light and sensitive SPA-3, which is affected by the energy of the gamma rays.) Average background reading using the PIC was 10 microR/h. Nevertheless, BNI/EIC regarded the site an unusual calibration problem because of the mixture of nuclides, the irregular distribution of contamination, interference by surface and subsurface water, and interference from other buried materials such as metal and building rubble. Ability to detect environmental gamma radiation is influenced greatly by the presence of shielding by water and rubble, etc. [As indicated elsewhere, the soil itself at the ^ pack landfill is likely highly heterogeneous, being brought to the site from various sources.]

The BNI/EIC report (Section 4.2), also states that radium is present both in the natural state as a daughter in uranium decay chain and as discrete sources. However, the site documents contain no other suggestion of a source for significant amounts of radium as a decay product. That is, no uranium ore or tailings from processes, that would account for the presence of decay progeny, on this site, was seen in the NRC investigation or in either survey report. Accordingly, this statement in the BNI/EIC report appears to be in error. All significant (greater-than-background) levels of radium-226 on site appear to be from discrete hardware items disposed of at the site.

For the BNI/EIC survey, a minimum of four surface samples were collected in the vicinity of each surface area identified in the ORNL as showing >50 microR/h gamma readings. Samples were soil plugs 3/4-inch diameter to 6 inch deep.

Boreholes were drilled, many being selected based on the ORNL report, extending where ORNL had stopped at the water table with elevated radioactivity. BNI analyzed samples from the sides of boreholes, finding good agreement with the results of the ORNL samples where locations were essentially the same. Where BNI extended the boreholes below the water line (where ORNL had stopped), radionuclide contamination was found to penetrate deeper and was found up to 11 feet below the 1982 surface.

BNI performed gamma logging of boreholes as did ORNL. Both used sodium iodide crystal solid-state scintillation devices for this purpose. BNI did not use a lead shield with collimation slits as did ORNL. BNI thereby gave up directional capability provided by ORNL's method, but increased sensitivity to gamma radiation from contaminants anywhere in the vicinity of the probe. Correlation of the gamma logging data with the results of soil sample analysis was only fair. In general, the gamma logging data seemed to under-represent the radium and/or uranium concentration at spots where soil sample radionuclide concentration results were high. The correlation was not discussed specifically in the BNI report, but seems likely to have been an adverse effect of shielding by water either saturating the soil or possibly even standing in the borehole outside the plastic pipe that was used for the gamma logging. Alternatively, high analytical results could in some cases be a result of the spotty nature of the contamination. In some cases where two boreholes were drilled \viin the same coordinates - in the same location - suostantial differences in contamination were seen between the two boreholes. (See, for a worst-case example, gamma-ray profile for two holes drilled at coordinates 435N,S and 348 E,W, Table 4, BIN/EIC, page A-109.) This is further evidence of the "spotty" nature of the radioactive contamination on site.

BNI subsequently used these gamma logging data to determine depth of contamination in the boreholes, any apparent elevation in gamma reading being taken as evidence of contamination at that depth.

Seven ground water sampling wells wert installed on the north and east sides of the landfill, in areas assumed to be free of radioactivity, for monitoring possible migration of priority pollutants and radioactive material in ground water from the site. (See BNI/EIC, Figure 3-6. Also ERM, Appendix A, Work Plan Supplement, Figure 9, DOE-1 through DOE-5, and DOE-7.) These ground water samples showed no elevated radionuclide levels, showing no migration beyond the site boundary as of 1982 (BNI/EIC Table 8). In 1992 ERM-New England, Inc., performed radiological screening on six of the wells that were considered to be in useable condition, in connection with chemical contamination characterization work. Unfiltered samples showed gross alpha screening results up to 37.9 +/-12.9 pCi/L, indicating little or no migration of radioactivity in ground water. (EEJvI, Appendix H.)

Radionuclide concentrations in surface water samples were all within the criteria limits of DOE r'rd.; 5 ! JO. 1A (DOE rule concerning residual contamination levels fro release of facilities from DOE activities) for uncontrolled areas, the guideline used by BNI/EIC. Individual samples ranged from less than 1 up to approximately 25 pCi/L

10 for three uranium isotopes combined. Five surface water samples, including two taken well outside the fenced area, contained more than 10 pCi/L combined uranium isotopes. Site background was not established for surface water, but would likely not exceed 3 pCi/L.

Radionuclide concentrations in sediment sample results were also low, but described only as "within the DOE criteria limits for soils —5 pCi/g plus background for radium-226 and 75pCi/g for uranium-238."

Ground water samples taken from boreholes were somewhat elevated, ranging from 0.1 to 6300pCi/L of U-238. This was compared to a 10 CFR 20 release limit of 40,000 pCi/L and a "stricter" DOE Order 5480.1 A release limit of 600 pCi/L.

BNI concluded from the data that removal of the "hot spots" would involve taking approximately 389 cubic mrvers of "soils" as low-level radioactive waste, but gave no detail in the report as to how this estimate was made. From the data presented in the two survey reports, the contaminated soils in the area of the swamp/pond at the east end of the fenced area, was not bounded by clean samples, i.e., the areal extent did not appear to be determined at that location. It is possible that the surveyors believed the limit of dumping in that direction could be determined and put a limit on the range of contaminated soils. However, the report did not so state.

In summary, the BNI/EIC survey and all others at this site have concluded that the distribution of contamination is spotty and uneven, both horizontally and vertically. The report also concluded that remedial effort could be deferred without harmful effect to individuals, the public or the natural environment, because of the physical and chemical stability of site radioactive contaminants.

11 2.0 PURPOSE AND SCOPE

2.1 Characterization of Radiological Contamination. The purpose of the survey will be to fill the data gaps in the characterization of radiological contamination of the Shpack Landfill site. The summary of previous radiological surveys at Shpack Landfill in Section 1.0 of this Plan indicates that there are data gaps as a result of the equipment and approach used during the surveys.

2.2 Survey Data Validity. A second purpose is to confirm the continued validity of survey data gathered in the ORNL (1980) and BNI/EIC (1982) surveys. The scope will be limited to the fenced area of the Shpack Landfill plus certain areas that receive runoff from the site due to likely topographical changes since the 1982 survey. These changes are likely to be subtle and could be caused by sediment deposits washed into the landfill from adjacent areas. Together with the prior surveys, the survey results should clarify the nature and extent of contamination on site, support evaluation of remedial alternatives and technologies, and provide input to future design of a final status survey.

This Survey Plan describes only the radiological survey activities and does not include any additional survey activity that may be carried out at the same or nearly same time for purposes of characterizing chemical contamination.

12 3.0 GENERAL APPROACH.

The general approach to the radiological survey provide ^ ;eview of the radiological contaminants of concern; familiarization with radiological survey guidance documents; and development of Data Quality Objectives.

3.1 Radiological Contaminants of Concern. Radioactive contaminants of concern will be uranium-238, uranium-235, uranium-234, and radium-226. All were introduced to the site as metals or metal oxides. While uranium-236 is recognized to be present at the site and establishes that the uranium source is recycled reactor fuel, several factors limit its importance. As a consequence of the process that forms it, U-236 cannot be found alone in the absence of the other uranium nuclides. As confirmed by analysis, the proportions of U-236 on site are small as a fraction of total uranium, 0.0043% to 0.293%. (ORNL, page 8.) Further U.S. EPA cancer slope factors for U-236 are virtually identical to those for U-235, indicating no special hazard associated with U 236. Accordingly, there is no indication that the presence of U-236 on site will make a significant difference in the health hazards presented by site contamination and U 236 need not be considered a contaminant of concern.

Additional radionuclides are known to be present, but are not principal radionuclides or contaminants of concern themselves, for the following reasons. Thorium-234 and protactinium-234m are short-lived progeny of uranium-238 that are presumed to be present in equilibrium with uranium-238 and are included in the dose conversion factors used for the latter. Similarly, thorium-231 and protactinium-231 are relatively short-lived progeny of uranium-235 that are presumed to be in equilibrium with uranium-235 and are accounted for in the dose conversion factors for uranium-235. The first progeny of uranium-234 is long-lived thorium-230, which cannot have accumulated significantly during the time of interest in remediation of this site. Progeny of radium-226 include radon-222 and the series of short-lived radon-222 progeny (polonium-218, lead-214, bismuth-214, and polonium-214) that are accounted for in dose-conversion factors used for radium-226.

13 3.2 Guidance Documents. The Multi-Agency Radiation Survey and Site Investigation Manual (MARS SIM) process has been developed in recent years and "finalized" in 1997, in collaboration by the U.S. EPA, Nuclear Regulatory Commission, Department of Energy, and Department of Defense. MARSSIM is recognized as the guidance for designing radiological surveys as applicable, which includes addressing soil contamination and contamination on building surfaces.

While MARSSIM is directed towaid the final status survey performed to demonstrate compliance with a dose- or risk-based regulation, after any necessary remedial actions, preliminary surveys such as this characterization survey should follow MARSSIM guidance so far as is feasible.

3.3 Data Quality Objectives. MARSSIM emphasizes the use of Data Quality Objectives (DQOs) and Data Quality Assessment processes, which don't seem to have applicability to the existing data that were gathered originally in the early 1980s. MARSSIM states that the stressing of DQOs helps assure that the site areas having a greater potential for contamination problems receive a greater share of the resources, and also serves to avoid unnecessary expense such as might be incurred in characterizing site contamination to a greater extent than is necessary.

To permit development of DQOs, MARSSIM also calls for early development of Derived Concentration Guideline Levels (DCGL). However, development of DCGLs for ionizing radiation will not normally be possible prior to completion of the characterization survey. Derivation of concentration guideline levels for the site, prior to final status survey, will grow out of some variation of a risk assessment process, which will consider appropriate scenarios and various exposure pathways in order to determine what contamination cleanup levels are necessary to meet Agency criteria. The Agency criteria will be expressed in terms of risk or dose. The risk assessment process, in turn, will require the use of the site contamination data from the radiological characterization survey.

Cleanup criteria will be expressed in terms of risk or in terms of dose to some human receptor, which is directly related to risk. For example, the Commonwealth of

14 Massachusetts (through the Department of Public Health) has promulgated rule 105 CMR 120.291 as a regulation for vacating premises with radioactive contamination. This rule provides that residual contamination on site should result in an annual effective dose equivalent less than ten millirem, above background, through all routes of exposure combined.

The form of this Massachusetts rule is compatible with EPA policy, found in a Kic^andum OSWERNo. 9200.4-18, r _ - -1 -\-ust22, 1997, entitled "Establishment of Cleanup Levels for CERCLA Sites with Radioactive Contamination." This EPA policy makes clear that cleanup levels for radioactive contamination should be expressed as risk, exposure, or dose level rather than concentration levels in media Compliance wit'- this Massachusetts rule as a regulation or an ARAR, and compliance with EPA policy, imply a human health risk assessment process (dose assessment process). The risk assessment process determine what soil concentration level (Derived Concentration Guideline Levels), averaged over a site or possibly a survey unit, will achieve the required dose limit.

The dose assessment process will need to determine what scenarios for human exposure are appropriate, and also determine an appropriate way to deal with the extremely spotty nature of the contamination on site. It should be noted that under EPrt guidance ihe C'JGL v/iil also be affected by the other residual health risks r.t the site.

Because it is necessary to complete radiological characterization of the Shpack Landfill site prior to the performance of a human health risk assessment that would permit establishment of DCGLs for the site, the survey approach will be to apply sensitive methods that have been found suitable for such characterization surveys. Considering especially the small area of the site, it is expected that the capability to identify soil concentrations somewhat lower than those that have been used as release criteria by NRC and DOE, consistent with survey equipment broadly used in characterization surveys, will be sufficient.

15 4.0 SURVEY OBJECTIVES.

As stated above, the purpose of the survey will be to fill the data T-^S in the characterization of radiological contamination of the Shpack Landfill site and to confirm the continued validity of site data gathered in uie ORNL (1980) and BNI/EIC (1982) surveys. The stated purpose will be achieved by completing the survey objectives described in the following paragraphs.

4.1 Classification of Areas. For purposes of applying MARSSIM, the Shpack Landfill area inside the fence can be considered as one Class 1 area. Class 1 is defined as an area that has, prior to remediation, a potential for radioactive contamination or known contamination. It is recognized that results and conditions as the survey develops may make changes to the plan advisable. If modifications are determined necessary, they will be justified and documented with appropriate approvals.

4.2 Consistency with Past Surveys. To be consistent with the previously established grid system and the practice during previous site survey activities, the English system of units will be used for this survey. Where necessary, units in which standards are defined may be converted into English units.

4.3 Site Background Radioactivity. For purposes of this characterization survey, it should be satisfactory to continue use of the site background data gathered by ORNL in its 1980 survey. The external gamma background was 7 microR per hour. Soil background was 0.64 pCi/g for radium-226 and 0.66 pCi/g for uranium-238. Background for beta-gamma dose rate was 0.02 mrad/h.

16 5.0 FIELD SURVEY ACTIVITIES.

Field survey activities will consist of the following:

* Pre-survey activities to prepare the site for sampling activities;

* Surface gamma scan to identify all locations of elevated radiation levels — to include measurement of gamma radiation levels at 1 meter above the surface, for comparison with criteria to be established for the site;

* Collection of surface soil samples for any locations where standing water or soil saturation with water renders the surface gamma scan suspect;

* Drilling of additional boreholes in locations to include random locations where surface contamination was not indicated by surface gamma scan, and additional boreholes as necessary to establish the areal extent of radioactive contamination into th? water-covered swamp/pond area at the northeast end of the frnced a;oa;

* Ground water sampling of all boreholes after proper development to replace the 1980-82 survey work, which can no longer be considered a valid representation of ground water conditions; and

* Surface water and sediment sampling on site and in waters that receive runoff from the site, roughly equivalent to the sampling that was done in 1982.

5.1 Pre-Survey Activities. Pre-survey activities will include cutting interfering vegetation as short as is practical throughout the fenced enclosure, and re-establishing the reference grid coordinate system that was used for the 1980 ORNL survey and the 1982 BNI-EIC survey. (Figure 2.)

5.2 Surface gamma scan. The surface gamma data from the 1980-1982 surveys cannot be relied upon as accurate because weather, over time since 1982, may have eroded soil that formerly shielded radioactive material or may possibly have displaced surface material to somewhat different locations. Accordingly, a complete surface gamma scan is needed to update and complete site radiological information.

17 The grid used in the 1980 ORNL survey and the 1982 BIN-EIC survey (Figure 2) should be re-established for this survey so as to facilitate relating the existing data to the new survey data. A walkover strategy should be planned and documented to cover the entire surface of the site and record findings accurately.

With respect to instrument portability and sensitivity with sufficient ruggedness, the basic gamma survey instrument for this survey should be a 2-inch x 2-inch sodium iodide (thallium-activated) crystal scintillation meter equivalent to the Eberline Instrument Corporation SPA-3 used in both the 1980 and 1982 surveys. Under the default assumptions suggested in the MARS SIM manual, this instrumentation will be expected to detect soil concentrations of 2.8 picoCuries per gram (pCi/g) of radium 226 or approximately 80 pCi/g of natural uranium, and give slightly lesser sensitivity for enriched uranium and somewhat greater for depleted uranium. (MARSSIM Manual, Chapter 6, Table 6.7.)

As discussed above, it is not yet possible to establish DCGLs for the Shpack Landfill. A concentration of 2.8 pCi/g of radium-226 is roughly one-half of a cleanup level adopted by the Nuclear Regulatory Co'nmission and also by the U.S. Department of energy, and appears likely to be suitable as a Minimum Detectable Concentration (MDC) for radium-226. However, there is no assurance that MDCs of 80 pCi/g more or less for the forms of uranium on site will be adequate. Accordingly, additional sensitivity is needed for the detection of uranium.

To avoid missing significant areas of uranium contamination, areas where no elevation above background is detected with the 2-inch x 2-inch sodium iodide scintillation meter should be re-surveyed by means of an instrument with greater sensitivity for the lower-energy gamma rays of uranium. Such an instrument is the FIDLER (Field Instrument for the Detection of Low Energy Radiation) probe survey meter. (MARSSIM Manual, Appendix H, page H-32.) Those 100 m2 or larger areas in which contamination is not detected in the initial survey should be surveyed with the FIDLER or equivalent.

18 To obtain a calibration factor for the purpose of estimating true gamma radiation exposure rates from the Nal detector instrument readings, a pressurized ionization chamber instrument (PIC) should be used to make comparison exposure rate measurements. Approximately 10 locations should be selected from among those showing the highest gamma scan readings, and pairs of readings taken at each location at three feet from the surface — one with the Nal detector survey instrument and one with the PIC operated in integrating mode for maximum sensitivity.

5.3 Surface Soil Samples. Surface soil samples should be collected in locations closely coordinated with the surface gamma survey, in accordance with two rules:

1. Representative surface soil samples should be taken where standing water or soil saturation or any other material or debris is present and may shield materials that could otherwise show elevated readings, with a minimum of one sample for each 10 m2 (ten-foot square) of such areas;

2. Additional soil samples should be taken in locations where the surface gamma survey does not appear likely to be confounded by shielding, for the purpose of correlating the gamma surface readings as much as possible with surface soil concentrations. A minimum of 10 sucb samples should be taken and gamma readings at the point of sampling recorded, to include high-, moderate-, and low-reading locations.

In the ORNL and BIN/EIC surveys, surface samples were taken as cores %-inch in diameter and 6-inches deep. No problems with that technique were reported, and a similar technique (bulb planting tool) with suitable decontamination appears suitable for the surface soil samples.

5.4 Additional Boreholes. Subsurface sampling data from 1980-82 can generally be regarded as still valid. Consistent with the methods used in the BIN/EIC survey, additional boreholes should be drilled for subsurface sampling and gamma logging, extended beyond the limits of fill depth, as follows:

1. It appears that significant areas, large enough to miss substantial components of site contamination, were not drilled in the 1980-82 survey work because of an assumption

19 that subsurface activity would not be present where elevated levels were not seen on the surface. That assumption is not tenable, especially when actual boreholes show higher concentrations of radionuclides overlain by soil showing much less activity (Reference BNI 3/84, Table 3), and additional boreholes are needed.

2. In some instances, area extent of subsurface contamination does not appear to be established, as contaminated boreholes are not bounded by clean or by any other clear limit. One example is the swamp at the northeastern end of the fenced area. It appears that the radioactivity is assumed to be bounded by the end of the filled area, but that limit does not appear to be known accurately or well established.

Locations for additional boreholes (grid locations in accordance with the 1980 and 1982 surveys) could include: (See Figure 3.)

N/S E/W 100 225 350 150 600 100 450 150 550 50 50 175 225 400* 250 475* 350 450* 500 425*

*The last four borehole locations may be below water in the northeast swamp. There may be confusion between surface water contamination and contamination of the underlying soil, particularly if surface water contamination levels have increased over the years. For that reason, these should be cased boreholes, or some equivalent method to eliminate the influence of surface water or sediments.

5.5 Ground Water Sampling. Ground water data reported by the 1980-82 surveys showed ground water contamination, but the samples described were simply water t?ken from boreholes, and there was no apparent procedure that would distinguish aeruai ground water contamination from contamination that fell from the sidewalls of boreholes. In any case, ground water data from 1980-82 has very little usefulness for characterizing the site now. All new boreholes should be developed as wells are developed, to obtain valid ground water samples for analysis. Should these ground water samples show ground water contamination, further ground water sampling will be necessary to establish the lateral extent of ground water contamination.

5.6 Surface Water and Sediment Sampling. The surface water and sediment samples taken in the 1980 and 1982 surveys have very little usefulness for current site characterization, except possibly for comparison with present-day values at the same locations. Presumably, all surface water has been purged many times since 1982. Local sources of contamination that were causing the low levels of contamination seen in 1980 and 1982, may have long since depleted leaving no contamination at such locations. Additional contamination may have been washed into receiving bodies (depressions and swamp areas)and added to levels of sediment contamination already existing. Accordingly, these survey activities now need to be repeated.

Surface Water Sample Locations: (See Figure 4.)

N.S E,W N.S E.W

250 460 640 600 250 520 700 300 350 450 760 400 350 520 790 500 450 440 798 200 470 510 820 60 520 450 820 100 896 50

Sediment Sample Locations: (See Figure 5)

N,S E.W 200 460 220 460 225 494 260 500 300 460 300 500 320 500 360 500 400 460 406 500 440 460 440 500 480 460 480 500 500 500 520 420 520 500 560 420 560 500 640 600 700 300 760 400 790 500 798 200 820 60 820 100 896 50

6.0 ORGANIZATION AND RESPONSIBILITIES.

The Corps of Engineers and its contractor will be responsible for implementation of the Survey Plan. As a minimum, persons qualified by training and experience will be provided for the management of the survey project and for on-site Site Supervisor, Health & Safety Officer, and Quality Assurance Officer. This characterization survey for the Shpack landfill must be carried out by a contractor/entity with existing management systems including a Quality Assurance Program that is adequate to assure that survey results are the quality needed for their intended use.

6.1 Quality Assurance Project Plan. It is expected that a Quality Assurance Project Plan (QAPP) will be prepared by the survey contractor and submitted for agency review.

6.2 Data Assessment. To facilitate data assessment and future final-status survey planning, and consistent with MARS SIM guidance, the contractor will report the measurement uncertainly for every analytical result or series of results. These determinations should include all forms of instrument calibration and check source use, speed of instrument movement in survey activities, and any other factors considered relevant. All gamma survey notes should include any relevant observations as to the presence of standing water or saturated soils. In addition, consistent with MARSSIM guidance, the contractor will report a realistic minimum detectable concentration (MDC) for the measurement system as well as the method used to calculate the MDC.

6.3 Waste Handling. Survey operations will be carried out in a manner consistent with applicable rules on management and disposal of low-level radioactive waste. The potential for waste generation appears to lie minly in the generation of soiled disposable equipment. Such material will not be disposed of on-site, but will be containerized and managed as low-level radioactive waste. Any such material that is to be stored on-site will be identified, documented, and protected from weather and contact with persons in accordance with all relevant and appropriate requirements of 10CFRPart20.

26 7.0 REFERENCES.

BNI/EIC, Radiological Survey of the Former Shpack Landfill. Bechtel National, Inc. DOE/OR/20722-4. March 1984.

ERM, Initial Site Characterization Report. Shpack Landfill Superfund Site, Norton/ Attleboro, Massachusetts. 17 March 1993.

MARSSIM, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIMX NUREG-1575. EPA402-R-97-016. December, 1997.

NRC. Radioactive Material in Uncontrolled Location, Norton, Massachusetts. U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement, Region 1. Report No. 078-154-A.

ORNL, Radiological Survey of the Shpack Landfill. Norton. Massachusetts. Health and Safety Research Division, Oak Ridge National Laboratory. DOE/EV-0005/31. ORNL 5799. December, 1981