Frank E. Mangold
Health Physicist, Environmental Chemical Corporation

The Belding Warehouse Superfund Site (listed as H&K Sales) was determined to pose a total estimated risk of 2x10^-1 Lifetime Excess Cancer Risk by the United States Environmental Protection Agency (EPA). The primary risk driver was from the widespread radium-226 (Ra-226) contamination from over 30,000 aircraft instruments which were haphazardly stored in two 10,000 square foot warehouses. The total estimated volume of contaminated materials was 6,000 cubic yards. Environmental Chemical Corporation (ECC) was subcontracted to collect the radium gauges, remove and dispose the contaminated materials, decontaminate the warehouses, and release the facility for unrestricted use. ECC developed a shredding application supported by an in-depth sampling program based upon statistical models listed in the Draft Multi-Agency Radiation Site Survey and Investigation Manual. ECC health physicists created a unique and innovative segregation and survey program that effectively separated suspect hazardous components and identified material containing elevated concentrations of Ra-226. The process resulted in 55 rolloffs of waste having a Ra-226 concentration less than 0.185 Bequerels per gram (Bq/g) (5 picocuries per gram (pCi/g)) being disposed at a Type II Municipal Landfill, seven rolloffs greater than 0.185 Bq/g (5 pCi/g) being disposed at Envirocare of Utah, and drummed gauges being disposed at the US Ecology LLRW facility in Richland, WA. The facility was decontaminated using shot blast techniques and released for unrestricted use. A cost savings of over 50% was realized when regulatory and contractor health physicists worked together to create a practical means for interpreting characterization and release requirements. This innovative method of shredding and sampling is now being applied to the Benton Harbor Superfund Site in Benton Harbor, Michigan.

Environmental Chemical Corporation (ECC) was contracted by the U.S. Bureau of Reclamation (USBR) and the Environmental Protection Agency (EPA) Region V to conduct a Non-Time Critical Removal Action at the Belding Warehouse Superfund Site in Belding, Michigan. The objective of the removal action, which was conducted over a ten month period from January through October, 1997, was to consolidate and dispose of radioactive material at the site in a manner that would ultimately lead to the unrestricted release of the properties and all remaining material. ECC worked with the EPA and the Michigan Department of Environmental Quality (MDEQ) in developing a unique and innovative method of characterizing, segregating, and disposing over 6,000 cubic yards of radioactive and mixed waste at the site that resulted in a 50% budgetary savings to the government.

The Belding Warehouse (BW) is located in a commercial section of Belding, Michigan, near the center of the town. The BW is a single story brick and cement block building with three large rooms, each approximately 10,000 square feet in size, with a metal roof and concrete floors. The warehouse was used to store surplus military aircraft components including aircraft gauges and dials marked with a luminous paint containing radium-226 (Ra-226). The luminous paint tended to flake with age, leading to the spread of contamination throughout the warehouse buildings. In addition to the radioactive gauges, ECC identified over 20 radiologically contaminated waste streams within the warehouse that required assessment, decontamination, and/or disposal.

Many of the radioactive gauges were broken, and radon levels where initially ten times the EPA guideline of 0.148 Bq/L (4 pCi/L). Based on the EPA 1996 Engineering Evaluation/Cost Analysis (EE/CA) study, the site was judged to pose a total Lifetime Excess Cancer Risk 2 x10^-1. Initial gamma radiation levels at the site ranged from background values of 10 microsieverts per hour (m S/hr) to over 7000 m S/hr (7 milliroentgen per hour (mR/hr)) near the surface of the gauges. Preliminary sampling detected levels that exceeded criteria, guidelines, and regulatory levels considered protective of public health.

The project activities for the Non-Time Critical Removal at the BW site were separated into four distinct phases:

• Work Plan
• Site Health and Safety Plan
• Site Specific Radiation Safety Program
• Waste Management Plan

• Mobilization
• Site surveys
• Pilot studies for decontamination
• Waste sampling
• Initial gauge segregation

• Radium gauge removal activities
• Waste segregation and sampling
• Shredding activities
• Disposal at the local Type II Industrial Landfill and the Low Level Radioactive Waste (LLRW) facilities operated by Envirocare of Utah and US Ecology

• Free release surveys
• Processing of hazardous wastes
• Packaging, transportation, and disposal activities
• Free release
• Final building decontamination

To facilitate safe and efficient handling of the complex group of radiologically contaminated waste streams present at the site, ECC prepared extensive planning documentation, including over 40 radiation-specific Standard Operating Procedures, purchased reliable and practical equipment, and developed on-site laboratory capabilities and field testing methodologies. BW workers were extensively trained in segregation and radiological survey techniques focusing on radium-226. Suitable and cost effective disposal facilities were identified for each waste stream and local facilities were inspected and their record of compliance reviewed.

Four primary radiologically contaminated waste categories required characterization, segregation, and disposal including:

• Drummed radioactive gauges;
• Shredded debris;
• Unshreddable debris (i.e., large objects); and
• Hazardous wastes.

Decisions on how to characterize and dispose of each waste stream in the safest and most cost effective manner possible were based upon a unique set of data. Field observations, process knowledge, field measurements (collected using portable radiation detection equipment and hazardous waste field test kits), and laboratory sample analytical data were composited to develop the waste characterization profiles. Each waste stream required a radiological survey for release/recycle purposes and/or possible treatment for RCRA constituent concentrations prior to disposal. An innovative shredding technique was developed to reduce waste volume and allow for the efficient disposal of diverse waste.

ECC eliminated the primary radiological risk at the site by first removing the radioactive gauges. Over 30,000 intact and broken gauges, including 40 distinct gauge models plus a variety of radioactive switches, were segregated and sampled to determine the activity of specific gauge groups for database calculation of estimated total drum activity. The gauges were packaged in 55-gallon drums for shipment to the US Ecology LLRW facility in Richland, Washington.

In addition to the radium painted aircraft gauges, the BW contained miscellaneous components, including manufactured materials such as fasteners (i.e., nuts, bolts, and screws), machines, electrical components, and an aircraft fuselage; and general debris such as wood, paperboard, light weight metal, and plastic waste. After undergoing numerous radiation surveys, the material was shredded to reduce their volume using an enclosed 200 HP electric shear shredder equipped with 2" teeth within a hopper opening of ten feet. The shredding resulted in the production of a homogeneous non-gauge shredded debris waste stream suitable for statistically based sampling. Fifty-six rolloffs of shredded debris that surveyed at less than 0.185 Bq/g (5 pCi/g) were disposed of at an in-state Type II Industrial Landfill. Implementation of a detailed decision-making process for the shredded debris waste stream ensured that the waste was properly characterized and that appropriate decisions were made at a predetermined confidence level.

Large metal objects, including heavy machinery, aircraft engines, test benches, and other non-shreddable items were segregated out, size reduced if possible, decontaminated where practical by HEPA vacuuming and/or spray/wiping, and radiologically surveyed prior to release.

Suspect hazardous materials, including cadmium coated hardware, mercury gauges, leaded vacuum tubes, used oil/fuel, acid/lead batteries, and asbestos, were segregated to prevent "mixed waste" generation, and sampled and analyzed to identify individual hazardous waste streams. Field test kits were developed to provide a rapid identification method for determining the presence of lead, cadmium, or zinc coatings. Various samples were analyzed for PCBs/pesticides, reactive sulfide, reactive cyanide, Ra-226 activity, RCRA metals plus zinc and copper, semivolatile organic compounds, and TCLP screening.

Over 400 drums were filled with cadmium and lead coated nuts and bolts. Each drum was radiologically analyzed using a drum scanner equipped with a series of High Purity Germanium Detectors. The analysis focused on the Bi-214 daughter product of radium. After allowing a 30 day ingrowth period, the Minimum Detectable Concentration was less than 1 pCi/g. Upon verification of the absence of radium, the drummed materials were released to the site owner for unrestricted use.

After all waste was removed from the warehouse complex, ECC conducted comprehensive radiological surveys of the facility to locate and quantify the extent of residual radiological contamination. The final phase of the project involved decontamination of all floors, walls, and ceilings using HEPA vacuuming, wiping, and shot-blasting techniques. Final facility surveys by ECC and MDEQ verified that the site was successfully decontaminated below Nuclear Regulatory Commission Regulatory Guide 1.86 "free release" criteria.

The warehouses openings were sealed up to provide containment of any potential airborne Ra-226 particulates. Radon levels approaching 120 pCi/liter in the work areas led to the implementation of an engineering change consisting of placing two 10,000 cubic foot per minute HEPA filtered exhausters in the ceiling of the warehouses. Due to the absence of a protection factor for Rn-222 from a respirator cartridge (dual HEPA/activated charcoal filter) worker lung burdens were calculated using stay times documented on the exclusion zone sign in/sign out sheets, and using the committed dose equivalent formula and appropriate weighting factors.

Over 30,000 radioactive gauges were characterized by first using process knowledge gathered from the US Army and other government contacts. The gauges (consisting of switches, dials, indicators, knobs, etc.) contained luminous paint activated by the Ra-226. Since the amount of Ra-226 varied greatly from gauge to gauge, an inferred relation between surface dose rate and gauge specific activity was generated. Gauges were grouped according to type, each group was surveyed and an average rate for each group was obtained. A representative gauge from each group was analyzed by Quanterra, Inc using gamma spectroscopy and compared to the result generated by the ECC on-site gamma spectroscopy result. The gauge specific activity was determined and, using the drum inventory, a drum specific activity was determined. The net weight and the total activity of the drum contents were used to demonstrate compliance with the waste acceptance limit of 370 Bq/g (10 nannocuries (nCi/g)) for Ra-226 at the US Ecology LLRW facility. Each drum had to be sealed with a silicone caulk to prevent radon leakage during transport.

Shredding was conducted on a wide variety of approximately 6,000 cubic yards of contaminated aircraft components. Technical challenges included physical separation of suspect hazardous components and material considered unshreddable due to metal thickness, plus removal of any radioactive sources such as loose paint chips from broken gauge face plates. The field test kits used a series of acid drops and other catalysts that provided an immediate indication of whether the material contained cadmium, zinc, or lead.

The statistical sampling for the shredding utilized the non-parametric statistical tests which included the Wilcoxan Sign Rank (WSR) Test and the Quantile Test. Approximately 15 samples were taken from a 20 cubic yard rolloff of shredded debris and analyzed on-site using gamma spectroscopy. An elevated measurement comparison was conducted using the techniques outlined in the Draft Multi-Agency Radiation Site Survey and Investigation Manual (MARSSIM). The WSR test was used to determine if the degree of contamination remains elevated throughout the shredded waste. Conversely, the Quantile test identifies smaller areas of higher contaminant concentrations. Performed together, these tests ensured that only shredded waste with a mean < 0.185 Bq/g (5 pCi/g) is disposed of at the industrial landfill and that shredded waste with a mean ³ 0.185 Bq/g (5 pCi/g) is disposed of at a licensed radioactive disposal facility. One in 20 samples were also sent to the Argonne National Laboratory for replicate analysis. ECC developed a Quality Assurance Project Plan that specified tolerance limits for all the precision, accuracy, representativeness, completeness, and comparability (PARCC) parameters.

The operational health physics program included dosimetry badging and environmental TLD service provided by Thermo Nutech, bioassay and mixed waste samples analyzed by Quanterra, Inc., numerous portable radiation detection instruments manufactured primarily by Ludlum Measurements Inc., radon monitors manufactured by FemtoTech, plus various other personnel protective equipment supplied by many other vendors. During the free release phase of the project, ECC subcontracted the service a Canberra Q² drum counter through SEG to analyze 400 drums of cadmium plated nuts and bolts, looking for any residual Bi-214 gamma emission. The Ludlum Model 2221 SCA and 44-10 2x2 NaI detector, also used extensively throughout the project, worked well for general gamma surveys as did the Model 3 Ratemeter with the 43-90 and 43-5 alpha scintillation probes for alpha surveys.

ECC designed and successfully implemented a process that saved over 50% of the budget while satisfying the compliance requirements of all applicable Federal and State regulations. The following key actions led to the successful completion of the project:

1. Segregation of waste streams to facilitate the most cost effective means of waste disposal resulting in 55 rolloffs being disposed at a local Type II Industrial Landfill instead of a licensed LLRW facility.
2. Development of a unique method of on-site homogenization, sampling, and analysis of bulk forms of radioactively contaminated waste debris approved by EPA Region V and MDEQ. The program is currently being duplicated by ECC at similar radium site at Benton Harbor, Michigan.
3. Development of a close working relationship with the local Type II Industrial Landfill operators to establish a mutually acceptable means of documenting compliance with their waste acceptance criteria by developing a clear understanding of ECC=s on-site analytical capabilities and characterization programs.
4. Successful elimination of the public exposure risk by disposing over 30,000 radium dials and switches at the US Ecology LLRW Facility in Washington, eliminating the exposure risk and ultimately leading to the unrestricted release of two 10,000 square foot buildings.

The Belding Superfund Site was decontaminated and closed through close interaction and coordination between the contractor and regulators. A unique approach to meeting the regulatory requirements for free release and for meeting the disposal facility waste acceptance criteria was developed by ECC and approved by the EPA and MDEQ. The Type II Industrial Landfill acceptance of "special waste" such as radium-226 contaminated debris was a key to the successful performance of this project. ECC completed the project for less than 20% of the initial government estimate of $39 million (produced by the US Army) by developing a cost effective waste segregation and disposal methodology that implemented practical decision making and innovative field techniques.

Lessons learned and recommendations for the future include:

• The innovative shredding process developed and refined by ECC at the Belding Superfund Site proved to be a technically feasible method of disposing of large quantities of material from a radiologically contaminated site at low cost. This technique was subsequently effectively applied to the Benton Harbor, Michigan Superfund Site, and should be considered for application to lower cleanup costs at other radiologically contaminated sites across the country.
• The process of developing the new shredder methodology highlights the concept that regulatory interpretations should always be carefully analyzed by contractors and State and Federal regulators, working together, to look for the most practical way of implementing regulatory requirements.
• To make practical and efficient field decisions, it is important to bring the decision makers to the field. Close coordination between technical and operational field personnel, in conjunction with on-site regulatory personnel interaction, will ensure a compliant and continuous work effort.
• Work on the Belding project, which required use of a wide variety of disposal facilities, illustrated that the compliance understanding across the waste industry varies greatly. Nuclear industry compliance documentation requirements are much more stringent that those of the municipal waste industry. Future cleanup projects should tailor the time and effort allotted to preparation of compliance documentation to the type of disposal facilities which will be utilized.

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