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HomeMy WebLinkAbout952068.tiff RESOLUTION RE: ACTION OF BOARD CONCERNING ACCEPTANCE OF CONSERVATION EASEMENT FOR LAIDLAW SOUTH LANDFILL TO RESTRICT FUTURE USE OF LANDFILL AFTER CLOSURE TO PREVENT EXPOSURE TO RADON GAS WHEREAS, the Board of County Commissioners of Weld County, Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with the authority of administering the affairs of Weld County, Colorado, and WHEREAS, the Board has been presented with a Conservation Easement for Denver Regional Landfill (South), Laidlaw Waste Systems (Colorado), Inc., to restrict future use of the landfill after closure to prevent exposure to radon gas, and WHEREAS, the Board has also been presented with a letter dated September 27, 1995, from Benjamin P. Doty, P.E., of Doty and Associates, requesting authorization from the Commissioners to the Weld County Health Department to approve Laidlaw's request to accept Colorado School of Mines Research Institute contaminated soil as a special waste at the Denver Regional Landfill (South), and WHEREAS,the Board of County Commissioners heard all of the testimony and statements of those present, studied the request of the applicant and the recommendations of the Weld County Planning and Health Departments and all of the exhibits and evidence presented in this matter and, having been fully informed, finds that said conservation easement shall not be accepted and said request shall be denied for the following reasons: 1. The Board finds that the conservation easement is not currently necessary since the proposed waste is a type which the acceptance of would constitute a substantial change in the current Use by Special Review Permit and Certificate of Designation and that an amendment to the Permits would be required before accepting this waste. NOW,THEREFORE, BE IT RESOLVED by the Board of County Commissioners of Weld County, Colorado, that the Conservation Easement for Denver Regional Landfill (South), Laidlaw Waste Systems (Colorado), Inc., be, and hereby is, not accepted. BE IT FURTHER RESOLVED by the Board that the request from Benjamin P. Doty, P.E., of Doty and Associates, for authorization from the Commissioners to the Weld County Health Department to approve Laidlaw's request to accept Colorado School of Mines Research Institute contaminated soil as a special waste at the Denver Regional Landfill (South) be, and hereby is, denied. 952068 PL0415 Pt,/-/L;c/f CQ /ai ' 9elti RE: CONSERVATION EASEMENT AND ACCEPTANCE OF SPECIAL WASTE - LAIDLAW PAGE 2 The above and foregoing Resolution was, on motion duly made and seconded, adopted by the following vote on the 2nd day of October, A.D., 1995. BOARD OF COUTY COMMISSIONERS �� D COUNTY, SOLO DO ATTEST: 4�l/(,u�� ilk �0 �f! Dale K. Hall, Chairman Weld County Clerk to the Board /2 / � '7 / '2 arb a J. Kirkmeyer, Prb-TTeeem BY: ( � � � �a� 7 ;CJ Deputy Clerk tp the Board L- i � g George E. Baxter APPROV AS TO FQRM: 1 ;1/ 3� Fxrin �—� Constance L. Harbert y orney L / /7/ J) W. H. Webster 952068 PL0415 TOWN OF ERIE �'� � D COI,' TY' _,`,e 645 1 645IIOLBROOK,P.O.BOX 100 ERIE,COLORADO 80516 LOCAL(303)828-3843 (�,[ SE? 32 AM ! METRO(303)665-3555 e 8: S t FAX(303)665-3557 CLERK TO THE BO";np September 29, 1995 The Honorable Board of County Commissioners Weld County P. O. Box 758 Greeley, Colorado 80632 Re: Request for Approval of Doty&Associates for Acceptance of Radioactive Waste at Laidlaw Solid Waste Landfill Gentlepersons: I have been asked by the board of Trustees of the Town of Erie, Colorado, to write this letter to the Weld County Commissioners. The Board of Trustees of the Town of Erie have unanimously agreed that the request of Doty & Associates on behalf of the Colorado School of Mines to allow radiologically contaminated soil be accepted at Laidlaw, warrants extremely serious and extensive consideration prior to any action by the Weld County Commissioners. There are many reasons why a rush to accept this waste material should not take place including but not limited to the following: 1. There is no urgency for Weld County to approve of the acceptance as CSI's facility in Adams County has already met all approval requirements. 2. The expedited approval by the State involves a serious conflict of interest as the State of Colorado has secondary liability for the contamination at the contamination site. 3. There have been prior incidents with similar material of lower radiological magnitude, and in those cases, the Colorado State Health Department required removal to Utah. 4. There is clearly an increased danger of ground water contamination. (See Pg. 2, paragraph 2 of letter of August 11, 1995 from Roger Doak, Solid Waste Section, Hazardous Materials and Waste Management Division to Rick Hoffman of Laidlaw). 5. All of the requirements set forth in Mr. Doak's letter give a positive indication of the potential for contamination from wind, trucks and dust. 952068 6. The Certificate of Designation issued by Weld County appears to disallow radioactive materials of any kind (as opposed to "waste"). 7. There does not seem to be any problem for amending a Certificate of Designation under C.R.S. 30-15-401 et seq. 8. We have been advised that Weld County may have to comply with all of the requirements under C.R.S. 30-15-401 et seq., before accepting the waste in question. 9. In any event fairness should allow at least a month for local communities to give their residents a chance to air their views and the Commissioners should set their own hearings thereafter. For the foregoing and many other reasons, the Town of Erie strenuously objects to a rushed approval of acceptance of this material and respectfully requests that the Weld County Commissioners either deny the request or allow adequate time for consideration. Setting this matter for a public hearing with adequate notice and allowing time for parties such as Erie to seek opinions from their residents would be a fair and equitable approach and give further evidence of the increased cooperation between Erie and Weld County. It would be a clear statement to the entire County that the Weld County Commissioners have been and will continue to be careful and prudent stewards of the entire County's welfare. I respectfully thank you for considering this request. Sincerely, Victor F. Smith Mayor CAOFFICEWPWIN 952968 COMMISSIONERS WORK SESSION NOTES; September 25, 1995 Dale Hall, George Baxter, Connie Harbert, Barbara Kirkmeyer, and Bill Webster Staff: Vicky Sprague Rural Residents for Smart Growth: Monica Daniels-Mika, Pat Persichino, Lee Morrison, and Bruce Barker Rural Residents for Smart Development, a community group from the Ft. Lupton area, asked to be recognized by the board as a planning group. Members requested notification of meetings or issues affecting an area within a three-mile radius. Before deciding, the commissioners agreed they needed more information. Monica Mika will arrange a meeting with the group. Laidlaw: Jeff Stoll, Trevor Jiricek, Gloria Dunn, Pat Persichino, Lee Morrison, Bruce Barker, representatives from Laidlaw and the Colorado Department of Health Laidlaw has requested approval to receive a special waste containing radioactive constituents. Jeff Stoll presented a memo to the board asking the following question: Would the disposal of this waste from the Colorado School of Mines at Laidlaw represent a significant change to the existing design and operation plan for the facility and thereby require an amendment to their Special Use Permit? The board decided to consider the issue in the context of changes in the closure agreements. It will be considered conceptually (no language changes) as an item of business in a regular board meeting. This work session raised the question of administrative decisions made by staff versus board involvement in decision-making. The board decided it would be best to discuss this later, apart from any specific case. Emergency Medical Services Council Bylaws: Gary McCabe, Bruce Barker, and Cyndy Giauque The current bylaws of the Emergency Medical Services Council provide for 12 positions. The council recommended deleting the position represented by the 952068 Work Session Minutes, September 25, 1995 Page 2 Platte Valley Fire Protection District since that entity no longer has an ambulance service. The board agreed to delete the position. It was also suggested that a position be added to represent the Office of Emergency Management. The board agreed to do so. Cyndy Giauque will prepare a resolution for the board to amend the bylaws accordingly. cc: Commissioners County Council Don Warden Monica Daniels-Mika Pat Persichino Gloria Dunn Lee Morrison Bruce Barker Jeff Stoll Trevor Jiricek Cyndy Giauque Clerk to the Board 952068 SEP 28 '95 04:13PM DKOF&H LAW OFFICE P.2 CONSERVATION EASEMENT IN GROSS t) 09/28/95 t\i THIS CONSERVATION EASEMENT IN GROSS is granted by Iaidiaw Waste Systems (Colorado), Inc. ("Grantor") on this day of October, 1995, to Weld County, a Colorado Home Rule County and whose legal address is 915 10th Street, Greeley, CO 80631 ("Grantee"). WHEREAS, Grantor is the owner of the lands described on Exhibit A (the "Property"), attached hereto and made a part hereof; and WHEREAS, Grantor desires to prevent residences or any other permanently occupied building from being built on the Property by encumbering the same with a conservation easement pursuant to the provisions of C.R.S. Section 38-30.5-101, et seq.; and WHEREAS, Grantee, in accordance with its purposes and duties desires to prevent residences or any other permanently occupied building from being placed on the Property. NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby confessed and acknowledged, the Grantor hereby grants and conveys to the Grantee a conservation easement in gross, pursuant to Title 38, Article 30.5, of Colorado Revised Statutes, over, across and upon the Property, as described on Exhibit A hereto. The terms of this Conservation Easement are as follows: 1. The Grantor, its transferees and assigns of the Property shall not erect any residential structures on the Property. 2. The Grantee shall have the right to enter upon the Property to inspect for violations of the terms and covenants of this easement and to remove or eliminate any conditions or operations which violate the same, by injunction, if nwrPsory. No further right of access, entry or possession is conveyed hereby. 3. This easement shall run with the land. 4. The provisions hereof are binding upon and shall inure to the benefit of the parties hereto, their successors, assigns, heirs and personal representatives, and all persons who may hereafter acquire an interest in the Property or any part thereof. It is intended that the Conservation Easement herein granted and any other interest created under this Agreement vest immediately. If any further interests in land are created, those interests shall vest, if at all, within the lives of the individuals who have executed this document, plus 20 years. pp pC 4 SEP 28 ' 95 16: 16 303 353 6712 PAGE . 002 9520ad SEP 28 '95 04:14PM DKOF&H LAW OFFICE P.3 IN WITNESS WHEREOF, the said Grantor and Grantee have executed this Conservation Easement the day and year first above written. GRANTOR: GRANTEE: Laidlaw Waste Systems (Colorado), Inc. Weld County �j By: 6 � \By:� Its: �f" Its: ACKNOWLEDGEMENT STATE OF COLORADO ) COUNTY OF WELD ) The foregoing instrument was acknowledged before me this _ day of October, 1995, by as of Weld County. Witness my hand and official :y . My commission expires: O% Notary Public ACKNOWLEDGEMENT STATE OF COLORADO ) COUNTY OF WELD ) The foregoing instrument was acknowledged before me this_day of October, 1995, by as of Laidlaw Waste Systems (Colorado), Inc. Witness my hand and official seal. ��� O UU My commission expires: % fit" Notary Public c:Iwssimasmum sancor2ERYAin 2 SEP 28 ' 95 16: 17 303 353 6712 PAGE . 003 952068 DOTY & ASSOCIATES ENVIRONMENTAL,GROUND-WATER AND WASTE MANAGEMENT ENGINEERS 20011 GOLDEN GATE CANYON ROAD SUITE 100 GOLDEN,COLORADO 80403-8125 TELEPHONE:(303)279-9181 FAX:(303)279-9186 September 27 , 1995 1206-14 Weld County Commissioners 910 Tenth Street P.O. Box 758 Greeley, Colorado 80632 Subject: Request for Approval to Accept a Special Waste CSMRI Contaminated Soil Denver Regional Landfill (South) Laidlaw Waste Systems (Colorado) , Inc. Ladies and Gentlemen: On behalf of Laidlaw Waste Systems (Colorado) , Inc. , this is a request for authorization from the Commissioners to the Weld County Health Department to approve Laidlaw' s request to accept the above referenced material as a special waste at the Denver Regional Landfill. DESCRIPTION OF WASTE The Colorado School of Mines Research Institute (CSMRI) soil is currently stockpiled at the CSMRI site in Golden, Colorado. The soil was excavated from a tailings pond near Clear Creek and moved to its present location as part of an emergency removal action conducted by the EPA. The soil has been extensively characterized; it is not a hazardous waste under any definition but contains small amounts of radioactive elements. The soil contains radium-226 at a concentration of 47 picoCuries per gram (pCi/g) , uranium-238 at a concentration of 12 pCi/g, and other related radionuclides at equivalent or lower concentrations. The total volume of the CSMRI soil is estimated to be 20, 000 cubic yards. WASTE HANDLING PROCEDURES The CSMRI soil will be placed as a monofill in a portion of Cell B separated from that used by the normal customers. All trucks arriving at the landfill will be securely tarped. The trucks will present appropriate transportation forms identifying the CSMRI soil to the clerk in the cashier building. After review of the transportation forms, the clerk will direct the trucks to the location of the monofill for unloading. Once in the area of the monofill , the driver will uncover the trailer, back onto the monofill and unload the trailer. Truck and trailer tires will only contact daily cover placed at the end of the previous day; therefore, decontamination of the trucks will not be required. 952068 Weld County Commissioners Page 2 September 27, 1995 Doty & Associates The trucks will re-tarp and return to CSMRI . If dust is a problem during the unloading operation, water sprays will be applied to the soil. In addition, continuous air monitoring will be performed to document quantities of wind dispersal and to direct dust control measures. Disposal operations will be discontinued if wind speeds exceed 30 miles per hour. The CSMRI soil will be covered on a daily basis to minimize wind dispersal and to allow unloading operations without later decontamination of the trucks. Cover soil will be brought to the monofill in scrapers and placed at the edge of the fill. The cover soil will be pushed over the waste using a dozer in such a manner that the dozer tracks do not contact the waste. Thus, decontamination of the equipment used to cover the waste (the scraper and dozer) will also not be required. After all of the CSMRI soil has been received, an additional foot of intermediate cover soil will be placed over the waste. Finally, up to 150 feet of refuse will be placed over the soil before the fill reaches final grade. More complete details of the proposed handling procedures are presented in the following attachments. 1. Special Handling Procedures, CSMRI Radiologically Contaminated Soil, Denver Regional Landfill 2 . Design Details and Closure Specifications, Denver Regional Landfill 3 . Contingency Plan, CSMRI Radiologically Contaminated Soil, Denver Regional Landfill In addition, an assessment of the radiological risk associated with disposal of the CSMRI soil at the facility was performed by Mr. Dennis M. Smith, a certified industrial hygienist with considerable experience in the preparation of risk assessments. The risk assessment (Attachment 4) evaluated potential exposures to facility workers, off-site public during the disposal operation and on-site residents after site closure. The assessment indicates very small potential radiation exposures for any of these potential receptors (results are presented as Table 1) . The dose received by the most exposed person (the landfill worker during disposal operations) is roughly equivalent to the dose one would receive during three transcontinental air flights and is less than half the dose received during a medical x-ray (Table 2) . All exposures are considerably less than the regulatory limit of 100 millirems per year (mrem/yr) . SPECIAL WASTE APPROVAL PROCESS Typically, requests for approval to accept special wastes are made to the Weld County Health Department with copies to the 952068 Weld County Commissioners Page 3 September 27 , 1995 Doty & Associates Colorado Department of Public Health and Environment (CDPHE) . Both health departments evaluate the special waste acceptance requests on the basis of the facility permit and the solid waste regulations. Both groups must grant approval prior to acceptance of the material because of the dual jurisdiction incorporated in the solid waste regulations. Approval from CDPHE normally takes the form of a recommendation for approval to the Weld County Health Department. The request for approval has been pending with the Weld County Health Department since August 1, 1995. CDPHE requested additional information on August 11; Laidlaw' s response was issued on August 24 , 1995. ACCEPTABILITY OF CSMRI SOIL UNDER PERMIT/REGULATIONS The development standards of Use by Special Review Permit #972 (Attachment 5) allow the facility to accept non-hazardous, non- radioactive solid waste; based on extensive testing, the CSMRI soil is an acceptable waste under these terms of the permit. The CSMRI soil has been determined to be a non-radioactive waste in the same manner that more typical special wastes are determined to be non-hazardous, i.e. , by comparing the characteristics of the material to established regulations and standards. As you know, all materials contain some amount of natural radioactivity, examples of which follow. Material Concentration or Dose Potassium in human body 30 millirems per year On-site soils 3 picoCuries per gram Rose food (fertilizer) 15 picoCuries per gram Coal ash 50 picoCuries per gram None of these materials is classified as radioactive; however, other materials contain sufficient amounts of radioactive elements that they are regulated by the Nuclear Regulatory Commission and (in Colorado) by the Radiation Control Division of CDPHE. Materials may also be regulated based on the process by which they were generated. Regulated materials are radio- active waste if discarded and the facility is not permitted to accept them, nor does it wish to accept them. The CSMRI soil was determined to be acceptable for disposal in a solid waste landfill based on a detailed evaluation of the source of the material and the levels of radioactivity therein contained. The evaluation has been reviewed by the US EPA and by the Radiation Control Division of CDPHE. Both groups concur with the determination that the soil is a solid waste, in spite of its radiological content. EPA' s concurrence can be found at 952068 Weld County Commissioners Page 4 September 27 , 1995 Doty & Associates the bottom of page 3 of Attachment 6 ; CDPHE ' s can be found in Item 2 at the top of page 2 of Attachment 7 . Given that the CSMRI soil is a non-radioactive solid waste, it can be accepted for disposal at the facility under both the permit and the solid waste regulations. The recommendation for approval required from CDPHE can be found in the second to last paragraph on page 2 of Attachment 7. This paragraph also presents CDPHE' s opinion that the permit does not need modification to allow acceptance of the CSMRI soil. CONDITIONS OF APPROVAL We request that the Commissioners authorize the Weld County Health Department to approve Laidlaw' s request to accept the CSMRI soil for disposal . This approval should be granted on the condition that all procedures described in the attached plans be followed during the disposal operation and that the requirements of Attachment 7 also be met. Attachment 7 (the CDPHE approval recommendation) specifically requires that a notation on the property deed be recorded excluding future development of the property for residential purposes. If acceptance of the CSMRI soil is authorized, we will cause the notation to be recorded prior to acceptance of the waste. I trust that the foregoing and attachments are complete enough for your evaluation and approval. Your prompt attention to this matter is appreciated. Thank you. Sincerely, DOTY & ASSOCIATES Benjamin P Doty, P.E. cc: Rick Hoffman, Laidlaw Waste Systems (Colorado) , Inc. Kevin Carel , Laidlaw Waste Systems, Inc. 952068 Weld County Commissioners Page 5 September 27 , 1995 Doty & Associates Table 1. Exposure Estimates Exposure Period Person (mrem/yr) Disposal Worker 12 .8 Offsite adult male 0.75 Offsite adult female 0 . 69 Offsite 10-year old 1. 3 Post-closure Adult male on-site resident 4x10-28 Adult female on-site resident 3x10-28 10-year old on-site resident 7x10-28 Table 2 . Common Radiation Doses Dose Action (mrem/yr) one transcontinental round trip by air 5 Potassium in own body 30 Medical x-rays 40 Cosmic radiation at sea level 40 Cosmic radiation at Denver 65 1st year dose to average resident near Chernobyl 5, 000 From Wilson, R. and E.A. C. Crouch, 1987, Risk Assessment and Comparisons: An Introduction, Science, Volume 236, pgs. 267-270. 952068 ATTACHMENT 1 SPECIAL HANDLING PROCEDURES CSMRI RADIOLOGICALLY CONTAMINATED SOIL DENVER REGIONAL LANDFILL August 1, 1995 This document presents special handling procedures for the disposal of approximately 20,000 cubic yards of soil from the Colorado School of Mines Research Institute (CSMRI). The soil was excavated from a tailing pond near Clear Creek and moved to its present location as part of an emergency remedial action conducted by the EPA. The soil is a clayey sand with approximately three to four percent cobbles and approximately one percent miscellaneous debris. The miscellaneous debris consists of plastic, glass, wood, pipes, tubing, concrete block, rebar, bricks and other material. The soil has been extensively characterized; it is not a hazardous waste under any definition but contains low levels of radioactive material. The soil has been determined to contain radium-226 at a concentration of 47 picoCuries per gram (pCi/g), uranium-238 at a concentration of 12 pCi/g, and other related radionuclides at equivalent or lower concentrations. A radiological risk assessment has been performed which indicates that on-site workers will be exposed to extremely low levels of radiation during the disposal operation. Nonetheless, the following procedures will be used to minimize those exposures. 1. The CSMRI soil will be placed in Cell B which is underlain by a composite liner system. The soil will be placed as a monofill (all soil will be placed in the same area). The location and elevation of the monofill will be established by topographic survey before disposal begins. The base of the monofill will be approximately one acre in size (200 feet by 200 feet). 2. Routine disposal by our normal customers will be conducted in a separate portion of Cell B. 3. All trucks arriving at the landfill will be securely tarped. 4. The trucks will present appropriate transportation forms identifying the CSMRI soil to the clerk in the cashier building. The clerk will direct the trucks to the location of the monofill for unloading. 5. Once in the area of the monofill, the driver will uncover the trailer, back onto the monofill and unload the trailer. Truck and trailer tires will only contact daily cover placed at the end of the previous day; therefore, decontamination of the trucks will not be required. 6. The trucks will re-tarp and return to CSMRI. -1- 952068 Special Handling Procedures CSMRI Soil • Auqust 1, 1995 Laidlaw Waste Systems, Inc. 7. If dust is a problem, water sprays will be applied during the unloading operation. Water will be obtained from the on-site supply wells or from the sediment basin. A rented water truck will be used for the spraying operation. 8. Ambient air monitoring will be performed continuously during the disposal operation. A PM10 high-volume air sampler (Wedding & Associates, or equal) will be placed downwind of the operation and filters will be analyzed for gross alpha and beta on a weekly basis. 9. Disposal operations will be discontinued if wind speeds exceed 30 miles per hour, as measured by the anemometer at the cashier building. 10. The CSMRI soil will be covered on a daily basis to minimize wind dispersal and to allow unloading operations without later decontamination of the trucks. Cover soil will be brought to the monofill in scrapers and placed at the edge of the fill. The cover soil will be pushed over the waste using a dozer in such a manner that the dozer tracks do not contact the waste. Thus, decontamination of the equipment used to cover the waste (the scraper and dozer) will also not be required. Daily cover will be a minimum of six inches thick. 11. In order to further limit exposures, the number of workers involved in the operation will be minimized. Spotting and application of water sprays will be performed by a single worker. The spotter will wear tyvek coveralls and an air-purifying respirator while unloading operations are being conducted (personal protective equipment will be discarded into the monofill). 12. The spotter, heavy equipment operators involved in the operation, and the site manager will receive appropriate training prior to commencement of the project. The training will cover at least the following topics. Radiation principles Radiation protection practices Time, distance & shielding from radiation sources Survey instrument uses and principles Potential hazards and pathways of the project ALARA (as low as reasonably achievable) concepts Contingency procedures Waste handling procedures 13. After all of the CSMRI soil has been received, an additional foot of intermediate cover soil will be placed over the waste. It is anticipated that the monofill will be approximately twenty feet tall (including daily cover). After placement of the -2- 952068 Special Handling Procedures CSMRI Soil August 1, 1995 Laidlaw Waste Systems, Inc. intermediate cover, the location and elevation of the top of the CSMRI soil fill will be established by topographic survey. 14. At the end of the job, documentation of the location of the monofill, all transportation forms, regulatory and internal approvals, ambient air monitoring analytical results and any other pertinent information will be placed in the special waste files (a part of the facility's permanent operating record). -3- 952068 ATTACHMENT 2 DESIGN DETAILS AND CLOSURE SPECIFICATIONS DENVER REGIONAL LANDFILL August 1, 1995 1.0 INTRODUCTION This document summarizes the design details and closure specifications for the Denver Regional Landfill (South) which is owned and operated by Laidlaw Waste Systems (Colorado), Inc. The Denver Regional Landfill is a municipal solid waste landfill operating in full compliance with the requirements of RCRA Subtitle D (40 CFR Part 258) and the State of Colorado Regulations Pertaining to Solid Waste Disposal Sites and Facilities (6 CCR 1007-2). The site is located at 1441 Weld County Road 6, near Erie, Colorado. More specifically, the site is in the East 1/2 of the Northwest 1/4 and the West 1/2 of the Northeast 1/4 of Section 29, Township 1 North, Range 68 West, Sixth Principal Meridian, Weld County, Colorado (Figure 1). The total area permitted for landfilling operations is 150.6 acres (Figure 2). Approximately 56 acres in the northern half of the property were filled prior to approval of a revised design in 1992. These areas have been covered with one to three feet of compacted soil and portions under final cover (three feet of compacted soil) have been vegetated. The revised design divides the southern portion of the site into four cells (Cells A, B, C, and D as shown on Figure 2). The construction of Cell A was completed on December 8, 1992, and Cell B construction was completed in May 1994. 2.0 SITE SUITABILITY The geologic and hydrogeologic conditions at the Denver Regional Landfill are well suited for waste disposal operations. The site is underlain by the Laramie Formation which consists primarily of claystone with lesser amounts of siltstone, sandstone, and coal. These materials contain a few, thin, discontinuous horizons that produce very small quantities of ground water. The regional aquifer (the Laramie-Fox Hills) occurs at a depth of approximately 375 feet below ground and has been shown to be effectively isolated from the overlying materials. In addition, surrounding land uses are suitable for the operation and the population density is low. The land uses consist of past underground coal mining with associated surface operations, several disposal operations (two closed facilities and two permitted but not yet operational facilities), dry land farming, the Erie Airpark residential/airport operation, an auto salvage yard, limited residential uses, and extensive production of oil and gas. The nearest dwelling is approximately 2,000 feet northeast of the property; the nearest residential development is at the Airpark, approximately 5,000 feet southwest of the site. The runway at the Airpark is approximately 5,400 feet from the site. -1- 952068 Design Details and Closure Specifications Denver Regional Landfill August 1, 1995 Laidlaw Waste Systems, Inc. 3.0 FACILITY DESIGN & OPERATION The new cells have a composite liner with separate leachate collection systems to collect leachate from above the composite liner. The composite liner consists of three feet of compacted clay overlain by a 60 mil high-density polyethylene (HDPE) geomembrane (see detail on Figure 3). The clay used in the liner is derived from on-site excavation and is placed in lifts of eight inches or less. The clay is compacted to at least 95 percent of the standard Proctor maximum dry density at a moisture content of ±3 percent of the optimum moisture content. The clay liner is constructed to achieve a permeability of 1x10-7 centimeters per second (cm/s) or less. Construction of the liner system was intensely scrutinized by an independent engineering firm and all as-built details have been documented. The leachate collection system covers the base and sideslopes of each cell. The system is comprised of drainage material (fine to medium, uniformly graded, subrounded sand), leachate collection pipes (six inch diameter PVC with 1/2-inch diameter perforations encased in 1-1/2 inch drain rock), and a sump with an upslope riser pipe (18-inch diameter HDPE or equivalent). Leachate is removed from above the liner using submersible pumps installed in the sumps and recirculated on top of the landfill. The leachate collection system and excavation design are also shown on Figure 3. The area method of waste placement is employed at the site. Lifts of refuse (ten to fifteen feet thick) are placed horizontally across discrete disposal areas. By the end of each day, all exposed waste is covered with six inches of soil to minimize nuisance conditions (e.g., wind-blown debris, vectors, and odors). Areas which remain unused for more than one month or which are at final grade receive 12 inches of intermediate cover soil. Normally, the waste stream accepted at the Denver Regional Landfill is sufficiently homogeneous that segregation of wastes is not important. For documentation purposes, however, the location and elevation of areas filled are recorded on a daily basis. The disposal location of some special wastes (e.g., non-friable asbestos) is recorded on the waste manifest forms. At the request of particular customers, some special wastes are immediately covered to reduce scavenging (a special burial). The special burial locations are sometimes established by topographic survey. For this project, we will establish ea separate area in Cell B of approximately one acre in size which will be used exclusively for disposal of the Colorado School of Mines Research Institute (CSMRI) soil. The exact location of the monofill will be determined at the time the project starts based on the current fill geometry; however, a conceptual location is shown on Figure 2. We estimate that the CSMRI soil will be at least 800 feet from the closest toe of the landfill, and that it will be covered by as much as 150 feet of municipal solid waste when the site is closed. The limits of the CSMRI soil fill will be established by topographic survey so that the soil will not be disturbed in the future. -2- 952068 Design Details and Closure Specifications Denver Regional Landfill August 1, 1995 Laidlaw Waste Systems, Inc. Ground water, explosive gas, and the condition of the slopes and surface water control structures are monitored on a quarterly basis (March, June, September and December). Quarterly ground-water monitoring will continue through September 1995, when eight background samples will have been collected from each well. Beginning in 1996, ground- water monitoring will be performed semi-annually (March and September) for the remaining life of the operation. Monitoring of explosive gas and the condition of the slopes and surface water control structures will continue on a quarterly basis for the life of the facility. Leachate sampling for analysis of the parameters listed in Appendix IA and IB of the state regulations is performed annually in June and sampling for toxicity characteristic leaching procedure (TCLP) analysis is performed biannually in June (odd numbered years). Leachate is also sampled on a quarterly basis for analysis of temperature, pH and specific conductance. 4.0 CLOSURE As portions of the landfill reach the design grade, final cover is placed on top of the intermediate cover. The final cover consists of 2 feet of compacted clay overlain by 18 inches of general soil cover and six inches of topsoil. The final surface is vegetated using a grass seed mixture recommended by the Soil Conservation Service. The final cover has a nominal slope of 4 horizontal to 1 vertical. Drainage benches will be constructed on the final slope to minimize erosion. Cover details are shown on Figure 3 and the final grading plan is presented as Figure 4. The two foot thick compacted clay layer in the final cover will be constructed of select clay material obtained from cell excavations. The material must be free of particles greater than 3 inches in diameter, roots, vegetation, peat, organics and other deleterious material. The clay is placed in loose lifts having a maximum thickness of 8 inches and compacted with a sheepsfoot roller or equivalent. The compacted clay layer is compacted to at least 90 percent of the standard Proctor maximum dry density at a moisture content of ±3 percent of the optimum moisture content. The compacted clay layer is constructed to achieve a permeability of 1 x10-6 cm/s or less. Construction of the clay layer is inspected by an independent engineering firm in accordance with an approved quality assurance plan. Permanent surface water control structures have been designed for the 100 year, 24-hour event. These include benches in the final cover, channel downspouts, perimeter channels, diversion berms, culverts and the sediment basin (Figure 4). The system is designed to direct all on-site stormwater to the sediment basin prior to discharge. The system is being actively constructed as areas reach final grade. A gas management system is also being constructed as areas reach final grade. The system consists of multiple vertical wells and horizontal collection trenches connected by header piping to a single collection point. The vertical vents are constructed in phases -3- 952069 Design Details and Closure Specifications Denver Regional Landfill August 1, 1995 Laidlaw Waste Systems, Inc. when areas of approximately 10 to 20 acres have reached final grade and are under final cover. The horizontal collection trenches are constructed as waste is placed in the cells. The trenches are located approximately every 150 feet laterally and 60 feet vertically and slope into the fill a minimum of 3 percent. Solid pipe is placed in the trenches within 50 feet of the cover system. The collected gas will either be burned in a controlled manner (flared) or diverted for an alternate use. Condensate which collects at low points in the header system will drain into the waste. 5.0 POST-CLOSURE CARE Post-closure care of the facility will be performed for thirty years following closure. The site will be inspected semi-annually for the first ten years and annually for the next twenty. The inspection will include the following. Site security (fencing) Final cover (erosion layer) Vegetative cover Surface water control structures Ground-water monitoring system Gas monitoring system Gas control system Leachate collection system Ground-water, gas and leachate monitoring will also be performed as part of the inspection and the gas control and leachate collection systems will be operated as needed. Any site deficiencies will be promptly rectified. It is currently planned that the site will remain in a vegetated, undeveloped condition throughout the post-closure care period. Any other post-closure use will be designed such that the integrity of the final cover and other components of the containment systems are maintained. -4- �52068 FIGURE 1 LOCATION MAP TOY?) 1 �_ IIT COMMUNITY 16 ERIE 18 , DITCH \r— T1N,R68W r— s1sO \ �ry SpSO -5100 5200 19 20 21 (EYryQP /` Oa,„ 25 ND ( (*7tiy 4>� '�tT ,t� :'DENVER : 5250 REGIONAL.x.:.:: :ii>: LANDFILL:iii. Ce ::::: SOUTH) ::::; :' 30 ::: 29 .. 28 \sue o In J ^ 5200 � O Ill\ 5100 "N5250 CO r/ (----'''.--/ U� W< `\S'SO I520 5250 CD 41. 0 31 32 cFr• 33 C �s oo 3 U 52 Z V) �l T1N,R68W \ T1N,R68W W \ S T1S,R68W 1 S 5T1S,R68W N N W I— a 0 1000 2000 3000 4000 5000 6000 TOPOGRAPHY FROM THE EAS LAKE. ERIE. FREERICK AND I I I I I IAFAYETTE, COLORADO, USGS 7.5 MINUTE QUADRANGLE SERIES 0 SCALE IN FEET CONTOUR INTERVAL 50 FEET 952068 FIGURE 2 SITE LAYOUT n 0 N O ik C Y L F W N Z2 5Z0 0 W J o OF J 0 W u IX 1+1 W Zd' 500 d Q �\ W ,,„, \ LF,W 0 y IX 1-ZWL �oa dwce�J � I� 0 ,_ tct0 ct \ : _., 0 .„ 4 w? m x J ,oN a NQ Liii R II1%11‘ @ J¢ N O W cv D i to ~ a t+1 0 cn Q O v o 1 \ O v �M / W WW U i ,r, r) ~OC'JJ (0 .y�'� _Z VW/I W N U Th) , i ' dUCe 02 — W 0a k 6�J V / F C5 W O o m / 51 �_9`V �` ZA Ca J 5120 p,p M -J � I- ILJJ SUr 55x0 � o W _ _ --- _ j1 Ys ( 30 / m� a--11P) 0 a s CI (11DCL°CI g v 952068 FIGURE 3 DENVER REGIONAL LANDFILL DETAILS _I J „ lL 2 W; O } f•� J_ m o 7 5. w tr; _ w U noo cc II W $ La I- _Z IXJ Wi H Q X U ce O wJ J (X W -� It &of o i OZ O Z o '�� � 0 5 Og Q o�t 't n �o rz art ‘ sF h nF ' \J Si: U 3 R 111111111111111111 / l�/ \� SOD ` '��ffft��1 ! ce ct rn ' J or o'•' U o • LlNQ s, /111 , O 111-- OIZJo 1- N •,•.p ' U as Jr,u1 ,Ln <P r'l r Q O Z• 1 g U f, ,, M ttt n� \ n o r' I �" s '"�, fir'{ d �a to 1) l s U O �a IIr N 1 w I� $.� \ _ I1 \CO II. r',p :'i IE� I. N, , •W'! ° t i i i li % \ iic "t C { ry_ __ N a 1 �. w _ r r _ `'o _ m U W O i wJ CO U ¢o �V] F r Oaq2 ,Ws IIlis: �h o� •�wo :, r (` N \L - ' 511 _ / in O W L., II I— 3 w wo_ w0 w0 i— a t Q~ Q~ QV QU W y re U V UJ UJa QJs UJo_ MZ pN O O Q pw, Q V Q Vd wQ 7 5 JVVd JSV) JUN JVa NO] OV 952068 FIGURE 4 FINAL GRADING PLAN Q o s o� 1 o a a t 4 - 0p; gio 2 n ii%/ _ N rz z _ oQ N„ OOu $ LL V K 0 LL .. 5. O s}a 3 3� a N O i I V>4 Y, G w Pa' w n 0925� , / of 1\\ l2 a g I °m s S, `'aa�n 5230 ? �` 5220 OLZS ,., „ _ ,OLLS-� \ O�Ls ,... ,pay O9i5 \1 ,jcia \ S ���. °s i \ s VOOCS o' rec—r-------0ICS 6mJV W .'. V\I.�, wow �1 E. �\I a \ :II@ \ � wQ N1.1� •�a �I ybf\ slowavwi As NVN _ I • I p m N r 749 _ oo �rn �z NIn YS2 noo° "ad w Oo o vl ��n�ry� z o m J I 3 I , ooa I I i I'sl a z - o to , z , L5310CNI529 I Y 5300 • 5290 o / .-- 1 < Lcr1(7 LL a:r ° '. .. 1? U I 52 e0 5260 wo a. Z r " /� C z _� N VN_ c I I w lJ m 0190limill rn S150 1 I$ 5,70 / w��' .. } eN 5,60 ..0/aii/-Fl w ''' 5N0 ;0 0.S&L - .�e�l O h II. �j 5511010 ��w/��/'S110 \00 l,6 Q amp --'�l��J/—" y9 K celm J® ¢ z <tqlzo p_ w Q ¢ „Tro� � 952068 ATTACHMENT 3 CONTINGENCY PLAN CSMRI RADIOLOGICALLY CONTAMINATED SOIL DENVER REGIONAL LANDFILL August 1, 1995 1.0 INTRODUCTION This document presents a contingency plan for the disposal of approximately 20,000 cubic yards of soil from the Colorado School of Mines Research Institute (CSMRI). The soil is a clayey sand with approximately three to four percent cobbles and approximately one percent miscellaneous debris. The soil has been extensively characterized; it is not a hazardous waste under any definition but contains low levels of radioactive material. The soil has been determined to contain radium-226 at a concentration of 47 picoCuries per gram (pCi/g), uranium-238 at a concentration of 12 pCi/g, and other related radionuclides at equivalent or lower concentrations. 2.0 IDENTIFICATION OF POTENTIAL INCIDENTS The CSMRI soil will be placed as a monofill in a portion of Cell B separated from that used by our normal customers. All trucks arriving at the landfill will be securely tarped. The trucks will present appropriate transportation forms identifying the CSMRI soil to the clerk in the cashier building. After review of the transportation forms, the clerk will direct the trucks to the location of the monofill for unloading. Once in the area of the monofill, the driver will uncover the trailer, back onto the monof ill and unload the trailer. Truck and trailer tires will only contact daily cover placed at the end of the previous day; therefore, decontamination of the trucks will not be required. The trucks will re-tarp and return to CSMRI. If dust is a problem during the unloading operation, water sprays will be applied to the soil. Disposal operations will be discontinued if wind speeds exceed 30 miles per hour. The CSMRI soil will be covered on a daily basis to minimize wind dispersal and to allow unloading operations without later decontamination of the trucks. Cover soil will be brought to the monofill in scrapers and placed at the edge of the fill. The cover soil will be pushed over the waste using a dozer in such a manner that the dozer tracks do not contact the waste. Thus, decontamination of the equipment used to cover the waste (the scraper and dozer) will also not be required. After all of the CSMRI soil has been received, an additional foot of intermediate cover soil will be placed over the waste. Potential incidents that may occur during these operations are as follows. 1. Mechanical problems with haul trucks 2. Traffic accidents 3. Traffic directly on the CSMRI soil -1- 952068 Contingency Plan CSMRI Soil August 1, 1995 Laidlaw Waste Systems, Inc. 3.0 EMERGENCY COORDINATOR In the event that any of the listed incidents occur, the emergency coordinator must be immediately notified. The emergency coordinator position can be filled by the following personnel (in descending order). Site Manager Rick Hoffman Office: (303) 673-9431 Home: (303) 532-4074 Operations Manager Don Starrett Office: (303) 673-9431 Home: (303) 451-8334 Shift Foreman varies All incident responses (as described in Section 4.0 of this document) will be under the direct control of the emergency coordinator. The responsibilities of the emergency coordinator are as follows. o Before an Incident arrange for qualified alternate emergency coordinator - have knowledge of hazards of the material and appropriate responses in an emergency - arrange for appropriate training for all potentially involved personnel o During an Incident correct imminent safety hazards, to the extent possible - limit access to the area and number of personnel involved - make appropriate notifications follow response procedures contained in this document conduct all activities such that personnel exposure and potential environmental damage is minimized o After an Incident evaluate potential for residual contamination and long-term impacts - prepare appropriate documentation (including proposed actions to preclude repetition of the incident) - make appropriate notifications and filings institute procedural changes to preclude repetition of the incident -2- 952068 Contingency Plan CSMRI Soil August 1, 1995 Laidlaw Waste Systems, Inc. 4.0 INCIDENT RESPONSE Mechanical Problems with Haul Trucks Mechanical problems with the haul trucks are not expected to pose potential exposure problems. If the tractor is disabled, it will be towed from beneath the trailer and a replacement tractor brought to the site to complete the unloading operation. Alternatively, the tractor-semitrailer combination may be towed in a loaded condition to a convenient onsite area for repair. The trailer will then be unloaded after repair is complete. Similar actions will be taken for flat tires or other problems. In no event will the load be transferred to another trailer. Traffic Accidents Although all onsite roads are routinely maintained and signage is posted limiting speeds, traffic accidents occasionally occur at the landfill. The only accidents with potential to pose exposure problems are those involving spillage of the CSMRI soil. Should such an incident occur, the area will be immediately cordoned off using traffic cones and hazard tape and all traffic will be directed onto alternate routes. If alternate routes are not available, the landfill will be closed until the situation is resolved. After traffic control is achieved and emergency treatment given to any injured parties, the following will be notified by radio (onsite personnel) or telephone. Emergency Coordinator (in descending order) Site Manager Rick Hoffman Operations Manager Don Starrett Shift Foreman varies Erie Fire and Rescue (for medical emergencies) (303) 828-3883 Dacono Fire Department (for fires) (800) 289-9353 or 911 Colorado Department of Public Health & Environment Roger Doak (303) 692-3437 Greg Brand (303) 692-3064 Weld County Health Department Trevor Jiricek (303) 353-0635 x 2232 Laidlaw Waste Systems Engineering Office Kevin Carel (817) 485-9950 x 240 -3- 952068 Contingency Plan CSMRI Soil August 1. 1995 Laidlaw Waste Systems, Inc. After these notifications have been made,the spilled material will be returned to the trailer from which it came, using a frontend loader. If the trailer is too badly damaged, a replacement trailer will be obtained. Every effort will be made to minimize fugitive dust and traffic over the spilled soil. Water sprays will be applied to the spilled soil if necessary to limit fugitive dust. An additional six inches of soil will be excavated from the area and loaded into the trailer to minimize potential residual contamination. The trailer will then be tarped, moved to the monofill and unloaded. The outside of the trailer and the frontend loader will be decontaminated at the monofill using a portable steam cleaner. Decontamination fluids will be contained inside the monofill and covered with clean soil at the end of the day. All personnel involved in these activities will have received appropriate training, as described in the Special Handling Procedures for this material. After the clean-up and decontamination are complete, the equipment involved in the incident will be screened for residual contamination using hand-held detectors, as will the area of the spill. If the screening cannot be performed promptly, the equipment will be parked adjacent to the monofill and the spill area will remain cordoned off until the screening can be performed. Again, all personnel involved in these activities will have received appropriate training, as described in the Special Handling Procedures for this material. After the screening is complete, the emergency coordinator (site manager) will prepare written documentation of the incident. The documentation will include the following. Description of incident (including date & time) Personal injuries Description of response (including date & time) notifications spill clean-up unloading equipment decontamination screening Analysis of likely causes Procedural changes intended to preclude repetition of incident The documentation will be attached to the special waste file for the CSMRI soil and entered in the facility's operating record. In addition, copies will be mailed to all notified parties. Traffic Directly on the CSMRI Soil If a haul truck or piece of landfill equipment directly contacts the CSMRI soil, those portions contacting the soil will be decontaminated at the monofill using a portable steam cleaner. Decontamination fluids will be contained inside the monofill and covered with clean soil at the end of the day. After decontamination, the equipment involved in the -4- 952068 Contingency Plan CSMRI Soil August 1. 1995 Laidlaw Waste Systems, Inc. incident will be screened for residual contamination using hand-held detectors. If the screening cannot be performed promptly, the equipment will be parked adjacent to the monofill until the screening can be performed. All personnel involved in these activities will have received appropriate training, as described in the Special Handling Procedures for this material. After the screening is complete, the emergency coordinator (site manager) will prepare written documentation of the incident. The documentation will include the following. Description of incident (including date & time) Description of response (including date & time) equipment decontamination screening Analysis of likely causes Procedural changes intended to preclude repetition of incident The documentation will be attached to the special waste file for the CSMRI soil and entered in the facility's operating record. -5- 952068 ATTACHMENT 4 A DOSE ASSESSMENT FOR EMPLACEMENT OF THI: CSl7RI WASTE SOILS AT THE DENVER REGIONAL LANDFILL (SOUTH) August 24, 1995 Prepared by Technical&Management Systems & Services 73 Spyglass Dr. Littleton, CO 80123 (303) 933-8875 D.M. Smith, CIH 952068 Dose Assessment for The Emplacement of CSMRI Waste at the Denver Regional Landfill (South) IS Introduction This document presents an evaluation of the potential radiological doses associated with the plan to permanently dispose of waste materials from the Colorado School of Mines Research Institute(CSMRI) at the Denver Regional Landfill(South)located in Weld County, CO. The Denver Regional Landfill is a municipal solid waste landfill operating in full compliance with the requirements of RCRA Subtitle D (40 CFR 258) and the State of Colorado Regulations Pertaining to Solid Waste Disposal Sites(6 CCR 1007-2). The regulatory history detailing the investigation, risk analysis, and analysis of alternatives of this project conducted under the direction of the USEPA(Region VDT) can be reviewed in Removal Action Options Analysis Colorado School ofMines Research Institute Golden Colorado(hereafter referred to as USEPA, 1995). Based on provisions of the governing order(Unilateral Administrative Order No. CERCLA-VIII-95-6), the preferred remedial alternative is to dispose the estimated 20,000 cubic yards of contaminated stockpile soil(the"CSMRI waste")in an approved off-site solid waste disposal facility(USEPA, 1995). This preferred alternative was selected because it provides high overall protection of human health and the environment, complies with the legally applicable or relevant and appropriate requirements,has low short-term risks during implementation,provides a permanent solution,is cost effective and is expected to have community acceptance(USEPA, 1995). The analysis provided in this report is intended to meet the requirements for a "Radiological Risk Assessment" established by the Colorado Department of Public Health and the Environment(CDPHE)Radiological Control Division("the Division). The CSMRI waste is comprised of an estimated 20,000 cubic yards of soil materials with the approximate radiological assay shown in Table 1. Table 1 CSMRI Radiological Assay for Dose Assessment' Constituent Activity Concentration(pCi/g) 'Radium(76Ra) 47 �t Ihorium(atTh) 2.8 70ThoriumC °Th) 24 rnThorium(mTh) 3.8 The waste will be deposited in a specified cell(approximately 200 feet by 200 feet)near the center of the landfill and will be covered by approximately 155 feet of materials including refuse, soil cover materials, and a compacted clay cap (material details are presented later in this report). The remainder of this report presents the radiological dose assessment Section 2 discusses the assessment methods including: identification of relevant exposure pathways, exposure estimation techniques and the methods of dose assessment Section 3 presents the findings, and Section 4 This assay is derived from several sampling episodes. Table 1 information is taken from Table 2-8 of USEPA 1995 and represents conservative.upper-bound concentrations. Discussions with the Division indicate that this data is considered appropriate for this assessment(CDPHE, 1995-discussion). 952068 discusses the findings in terms of their reliability for use in risk management. References are foimd in Section 5. 2.0 Assessment Methods The methods used for this assessment are conventional and conservative;they are regarded as health protective in that they tend to err on the side of safety by overestimating exposures and doses. The following sections summarize the methods and details are presented in Appendix A. Li Pathways of Exposure Exposure occurs when humans come into contact with radionuclides mainly through inhalation, ingestion,through open wounds, or by external irradiation from gamma producing nuclides. For purposes of this assessment, the following three exposure scenarios will be evaluated: A) Workers at the landfill who could inhale radionuclide containing dust and 222Radon gas enItn) and its daughter products during placement of the waste material in the landfill This pathway will be evaluated by assuming inhalation of a suspended particulate(i.e., dust) concentrations containing radionuclides, in combination with inhalation of estimated u2Rn gas concentrations emanating from the disposal cell prior to application of the final cover. B) Members of the general public who could also inhale radionuclide containing dust and 222Rn gas during placement of the waste material in the landfill. This pathway will be evaluated by approximating suspended particulate concentrations containing radionuclides and 222Rn at • the nearest fence line and assuming exposure during the actual land filling operations. This will be accomplished using data from above(i.e., A))and a simple air dispersion modeL C) A member of the public who,hypothetically,lives in a house constructed on the surface of the landfill directly above the waste material. This pathway will be evaluated by approximating 222Rn gas and its daughter products emanating, after closure, from the 26Ra deposited in the landfill. Starting(i.e., source-term) concentrations for all pathway estimations will be taken from Table 1. Radiation dose from external gamma is not considered an important exposure pathway because of the comparatively low photon energy of the principal radionuclide of concern, 226Ra(0.186 MeV, 3.3% (Eisenbud, 1987)), the short time duration of exposure(400 hours), the relatively large distance from the source to workers(several meters or more)and the public(hundreds of meters), and shielded aspect of the dilute source term in soil(226Ra concentration in the waste is about 48 parts per trillion on a mass basis). 2.2 Workers Exposure During CSMRI Waste Emplacement Landfill workers involved in waste emplacement are potentially exposed through: 1)inhalation of particulate matter generated from waste handing, and 2)inhalation of n2Rn and daughter products2. Computational details can be found in Appendix Tables A-1 and A-2. The major assumptions comprising the assessment of worker doses are: 2 The main dose contributing gRn daughters are: -"Po(RaA), "'Pb(RaB),and"'Bi(RaC)as well as to(RaA*)itself(NCRP. 1991). 2 952068 Inhalation rate: 10 m'/day Exposure period: 50 days • Sustained particulate concentration: 1.0 mg/m' • Wind speed: 2 m/second(calm) mRn flux based on a 50 day average of 0.916 pCi/m2-second giving a sustained average mRn concentration of 6.98 pCi/m'above the landfill overlying the waste. • Wind blows directly to each worker 100% of the time. Source-term concentrations from Table 1 Inspection of Figure 1, on Table A-3.2 (contd.) reveals the important attenuating effect that cover depth has on n'Rn flux diffusion estimates. 2_3 Offsite Public Exposure During CSMRI Waste Emplacement During waste emplacement, members of the general public are potentially exposed thro»gh: 1) inhalation of particulate matter generated from waste handing, and 2)inhalation of mRn and daughter products. Computational details for the general public are also found in Appendix Tables A-1 and A-2. The major assumptions comprising the assessment of doses to the general public are: • Inhalation rate: 20 m3/day Exposure period: 50 days • Exposure location: nearest fence line approximately 900 feet from the disposal cell Sustained particulate concentration: 0.0007 mg/m' Wind speed: 2 m/second(calm) Radon flux based on a 50 day average flux of 0.916 pCi/mm-second giving a sustained fence line average=Rn concentration of 4.6 E-3 pCi/m3 ▪ Wind blows to the fence line receptor 100% of the time Source-term concentrations from Table 1 Comparing Sections 2.2 and 2.3 indicates that: 1)both use the same source terms, 2)workers inhale 10 m'per eight hour day while offsite receptors inhale 20 m'reflecting twenty four hour exposure, and 3) landfill and fence line concentrations vary by the "chi"factor of 0.00066 derived from Tuners' dispersion equation for"D" atmospheric stability conditions(Tuner, 1970). 2_4 Hypothetical Public Future-Home Atop the Landfill To evaluate potential doses to the public in a hypothetical future-use scenario, a theoretical 2rRn flux was computed using the method employed by the USEPA for the CSMRI Risk Assessment(See Appendix H, USEPA, 1995). Computational details can be viewed in Attachment A, Tables A-3.1 through A-3.3. The essential feature of the exposure and dose model are: • Four compartment flux and in-house distribution model(See Tables 2 and 3) consisting of. The waste material, 20,000 yards'at a 26Ra concentration of 47 pCi/g 155 foot cover material A four inch concrete slab-on-grade A standard"radon" evaluation of house: 100m2 base, 250m3 volume, air exchange rate of 1/hour(UNSCEAR, 1988) Occupancy rate of 100% Dose factors for 100% occupancy from NCRP 1985. 3 _95" 69 1 is ICI o N ° m t7 PI ICY I �I� w G C W QIoI o 0 - UIu I Z1 _ 1 m N L E m 5 01 1��I sl '°' E. E c Elm IIl- Iw 1aI gi S ••�! m' N m I ai 'ala�l° 'lo m1 H OI �I 0+m m 0 11 I 1 m i': i a°I oIc!o J'1 I" 4 al m • =1 mla .- EI aix-1 �1 ola la mi ml�, .31 cl>1 y l' it rls ;it vj 'o l ° Cml ° IHi ° Ul m ml v:alv ,1aa* °j01 m mlm /nI , I aU j m I tm Wmlyi- E , awmIA °Im1 <I et°�� UICCIC71 101 C.d WI al el Tel I! EI _cl ar mm1 m1' ci LICC f 931U�UI 1. . 1 Fil jI 1ci ji1 III II N ° RI m `LLI l ll U I°M m `al O iII 3 a1� x a! mu°-°Iwl ml _! a NI CI _1om� N `a- Olnl U- t/X� " W aiw•lil di 8 8 ~!_I �`I� t a a al 0I w NI NI of NI - �I CI m N cc, m O a `- c m m o = a o- • m 2 '� m N O1 ° mll mla�ala m133 s m mIm o c ml mlm ° ° 6I .i1-t1- ^i2I' E mm ° ^IQ U :AAA' 'illy! �!n_!�!WIW W 4 952068 Doses are estimated for adult males and females, and children of age 10. A notable characteristic of the model is the flux attenuation with cover thickness as illustrated in Table 2 and Figure 1 (on Table A-3.2). Waste material, cover, and concrete slab properties used in the model are shown on Table 3. 3_0 Results This section presents the dose assessment findings for the three pathways identified in Section 2.1. Comparisons are made to the accepted dose limitation of 100 mrem/year(NCRP 1993). 31 Worker Exposure During CSMRI Waste Emplacement Table 4 presents the effective dose equivalents(EDEs) estimated using the conventional and conservative methods discussed in Section 2.0. The estimated EDE for a worker spending 50 days processing the CSMRI-waste material is 12.3 mrem/year. Approximately 60% (7.7 mrem/year)of the dose stems from inhalation of particulates as might occur during transfer operations. The remaining 40% (5.1 mrem/year)is attributable to inhalation of 'Rn and daughter products emanating from the emplaced waste materials. As indicated in Table 4, this conservative estimate is well below the 100 mrem/year dose limitation recommended by the National Council on Radiation Protection and Measurements(NCRP 1993). 3.Z Exposures to the Off-Site Public During CSMRI Waste Emplacement Dose estimates (EDEs)for members of the public theoretically at the landfill fence line(900 feet from the waste cell) are presented in Table 5. The estimated EDEs for adult males (0.75 mrem/year), adult females (0.69 mrem/year), and a ten year old child(1.3 mrem/year) are all well below the 100 mrem/year dose limitation. The majority of the estimated dose( 84 to 92%), though small is attributable to inhalation of mRn and daughter products. These estimates assume continuous exposure at the fence line for the estimated 50 days processing period required for the CSMRI waste material 3_3 Exposures to a :ypothetical Future-Use Resident in A House Atop the Landfill In theory, at some time in the future, an individual could construct a home on top of the landfill overlying the 20,000 yards' of waste materiaL Conventional conservative flux and in house dispersion models were used to approximate potential exposure concentration and doses. The estimated EDEs for adult males(3.5E-28 mrem/year), adult females(3.2E-28 mrem/year), and a ten year old child(6.5E- 28 mrem/year)are all well below the 100 mrem/year dose limitation. Additionally,the computed�Rn concentration of 6.5 E-29 pCi/m'is well below the USEPA residential home guideline of 4.0 E+3 pCi/m' (4,000 pCi/m3). These estimates are so low as to be clearly within the realm only of computational interest. 4_0 Discussion and Conclusion The findings presented in Section 3.0 have been characterized as "conservative"in that they likely express overestimations of the true doses and attendant risks. In no case did the computed doses approximate the governing 100 mrem/year recommended limitation on exposure'. In order to gain ' This dose limitation conservatively assumes workers are actually members of the public who do not normally encounter significant exposure to radiation in the normal occupational environment. 5 952068 II 1 �aoIR �' I 1 mi cI V Q1 R. —� ml "m Q a o W l a oriel-e m mVI � 1 mee m m E A —ia alMg Ca a ia4 a cala 7:S 8 121 w oaa '01 •a ml� 0I0I 4"-e Pee o ?Im*ig H,C m ' tan .-w - e- . 1 r al 3 us _ I ofN Q WI ( ipp N ❑ 01,8SO 0t00 <I us yyIa 0101E G O O mu C 0 NV — U • C01 I I 1 :Im A) pial iggigS , 8 , j� �Ic o o o o 0 olinj al oI I a 'al o • . C ZI wI m El E ,iv aI N NI ' N p m J .. cI E adJ m c m ��qq 55�� J N m o o FINN23 � - m fl78a o �+m c c:t CO.= P. a m 0 °u m d' 1-,H'F L Eisi J um 03 m N _ to G O'WI ? TI CIV CO' a 'mj N t aI j C,-, • <I8IoIo of to _ Id 21 21 I UI G ei E wI a lio m dJ W �m • Sl I lU I cc m m it,of o "2d w � 0 �i of w $ ��_ m YI w ci ;6 l7 no J . 41 J of I mo OI ' .c O !Al < _VIE ti C �m) Nmm o � .4.. @� -ail m v la = `ij2 N c il. Nii. c .� !Li m cc 00 cliL NIm L 1 oUOO. m mlm � NJ LI -QI Clp S0 < m` K i j U YY ( twirl re a < • l'a o, z — sNaj^ o o E m E a jm = o m �I c E 8 ' ' E w o maI0p NaV DY . w E Q m vs col.- . Ucis ] OG as �0 II m13 mI N Z. 0NI GSI U NIm 1Ja a C NL CI C O mI . 42 NI E'QAf N d Km O �p C mUIUq m mQI 0JIO`GItLIL.LNOE uE m o aI N D JIu n - m UINIhI a NI 315 $ y m CCU O j 01 O WI mCI IN CI I IBI I I 6 cal m mjm Mai U N m -a mI O I =!a OlUOf ` m � • . : alNlo al _ awx.' I M. 952068 perspective on the findings of this report, Table 7 is provided to make comparisons that add insight to the assessment. Table 7 Comparison of Computed Doses and Exposure Parameters to Background and Related References Comparison Point CSMRI Dose Assessment Backgrotmd or Reference Terrestrial Based Fence 0.7 to 1.3 mrem/year(During 50 80 to 2,000 mrem/year in the Line Public Dose day emplacement) U.S. (NCRP, 1992) Outdoor 222Rn -Atop landfill(during 50 day 108 to 1,188 pCi/m3 in the Concentration emplacement): U.S. (NCRP, 1992) 6.98 pCi/m3 243 pCi/m3 average in the - Atop landfill(After U.S. (UNSCEAR, 1988) emplacement): 1.95E-23 pCi/m3 Indoor mRn 6.53E-29 pCi/m3 270 to 18,900 pCi/m3 in the Concentration U.S. (NCRP, 1992) 1,080 pCi/m3 typical in the U.S. (Derived from NCRP, 1992) 222Rn Flux from Soil Exiting 155 foot cover: 0.5 pCi/m2-second(NCRP, 3.69E-25 pCi/m2-second 1992) 222Rn Entry in Homes Exiting the 4" slab: 0.04 to 0.78 pCi/m3-second 1.82E-32 pCi/m3-second (UNSCEAR, 1988) Review of Table 7 reveals that the estimated doses attributable to emplacement of the CSMRI waste soils and exposure point estimates of mRn are well below those that occur normally. Insightful observations of interest include: 1) CSMRI related doses at the fence line during emplacement are well below background doses arising from terrestrial sources of naturally occurring radiation. 2) Estimated outdoor and indoor=Rn concentrations attributable to CSMRI wastes are also well below those reported as occurring in the natural environment 3) Estimated 222Rn fluxes from the 155 foot cover and into the home are well below what would normally be expected to occur. This observation lends insight into the two comparison points(doses and concentrations)made above. This section seeks to lend perspective to the estimated effect of implementing provisions of the governing Order(Unilateral Administrative Order No. CERCLA-VIII-95-6) specifying the preferred 7 952068 remedial alternative to dispose of the estimated 20,000 cubic yards of contaminated stockpile soil in an approved off-site solid waste disposal facility(USEPA, 1995). Based on this assessment,implementing the Order using the Denver Regional Landfill(South) as the solid-waste disposal facility would dearly support the USEPA's determination that the preferred alternative will provide a high overall protection of human health and the environment and that short-term risks during implementation are low. 5_0 References Division, July 1995, Discussion between G. Brand(CDPHE) and D. Smith(MISS). Eisenbud,M., 1987,Environmental Radioactivity From Natural. Industrial. and Military Source, Academic Press,New York. NCRP, 1993,NCR?Report No 116 Limitation of Exposure to Ionizing Radiation, National Council on Radiation Protection and Measurements, Bethesda, MD. NCRP, 1992,NCRP Report No 94 Exposure to the Population in the United States and Canada from Natural Background Radiation, National Council on Radiation Protection and Measurements,Bethesda, MD. NCRP, 1991,NCRP Report No. 77. Exposures From The Uranium Series With Emphasis on Radon and Its Daugltters,National Council on Radiation Protection and Measurements,Bethesda,MD. NCRP, 1985, NCR? Report No. 78. Evaluation of Occupational and Environmental Exposures to Radon and Radon Daughters in the United States,National Council on Radiation Protection and Measurements, Bethesda, MD. Revzan,KL., Fisk,W.J., and RG. Sexton, 1993, Modeling Radon Entry Into Florida Slab-On- Grade Houses,Health Physics, Vol. 65,No. 4. Rogers, V.C.,Nielson,K.K.,Holt, RB., and R. Snoddy, 1994,Radon Dion Coefficients for Residential Concretes, Health Physic%, VoL 67, No. 3. Turner, D.B., 1970, Workbook of Atmospheric Dispersion Estimates,USEPA Office of Air Programs, Research Triangle Park,NC. UNSCEAR, 1988, Sources. Effects_ and Risks of IonizingRadiation.United Nations Scientific Committee on the Effects of Atomic Radiation, 1988 Report to the General Assembly,with annexes, United Nations,New York. USDOE, 1993, Manual for Implementing Residual Radioactive Material Guidelines U .ig RESRAD, Version 5.0, ANL/EAD/LD-2, Argonne National Laboratories, Argonne, IL. USEPA, 1995,Removal Action Options Analysis Colorado School of Mines Research Institute Golden Colorado, Submitted to U.S. Environmental Protection Agency,Region VIE. USEPA, 1988,Federal Guidance Report No l I. Limiting Values of Radionuclide Intake and Air Concentrations and Dose Conversion Factors for Inhalation. Submersion. and Ingestion, Office of Radiation Programs, Washington,DC. 3 952068 Appendix A Computation Spreadsheets 952068 II l 1 I U: I ml E1 11 LL • CI • -01 1 • I r u yI I NI CM NI l r I NI `mI-I I :.:1 UI.. EI >ICI `1 m mlLeilloili44I ml mlCIm `10O0 Ei_. 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NI u NI �v a % m m Ca ol 11 n `'1ci i�1 CM m1 N SIN SI O G1`I= �i co m MILLI n, a NI V) �I CO NI 0,1 N ^I _ t.tt ❑I mi al at E" LL mIU NIU Nl ml�' ' • NiI3,co1 'NI '0 O1aiU1 NI IQ."raiYI .NI 'ICI NI ,aITI 0:n13,Qi 952068 ' ATTACHMENT 5 SITE SPECIFIC DEVELOPMENT PLAN SPECIAL REVIEW PERMIT DEVELOPMENT STANDARDS LAIDLAW WASTE SYSTEMS (COLORADO) , INC. USR #972 1. The Site Specific Development Plan and Special Review Permit is for an amended design and operations plan for an existing sanitary landfill permitted under SUP 0400, allowed to operate from 5:00 a.m. to 9:30 p.m. per day, seven days a week, except in certain emergency situations as approved by the Weld County Environmental Protection Services Division. Construction equipment may operate until 11:00 p.m. until December 1, 1992. The facility shall be operated in accordance with the application materials on file with Weld County, and subject to the Development Standards stated herein. The applicant and/or operator shall be responsible for constructing and operating in compliance with minimum standards pertaining to the Colorado Solid Waste Disposal Sites and Facilities Act and applicable Federal Laws. 2. Approval of this plan may create a vested property right pursuant to Section 90 of the Weld County Zoning Ordinance. 3. Only non-hazardous and non-radioactive household, industrial, and commercial solid waste, approved by the Colorado Department of Health and Weld County Environmental Protection Services Division, shall be accepted. No liquid waste of any nature, as defined by the State of Colorado or -- Environmental Protection Agency, shall be accepted. 4. A manager, knowledgeable in operating a solid waste disposal site and facility, shall be on the site at all times the facility is operating. An up-to-date list of all managers shall be provided to Weld County Environmental Protection Services Division. 5. The maximum size of the working face of the disposal site shall not exceed 150 feet in width and 14 feet in vertical depth at any time. 6. All waste received at the facility shall be inspected to ensure appropriate wastes are being disposed of at the facility. The access control plan, approved by the Colorado Department of Health and the Weld County Environmental Protection Services Division. shall be maintained. 7. There shall be a single point of ingress and egress to the facility. The approved off-site maintenance and improvements agreement shall identify the haul route. Weld County Road 7 shall not be used as a haul route. The main haul route shall be from State Highway 7 along Weld County Road 5. The secondary haul route shall be from Weld County Road 8 along Weld County Road 5. 8. The facility shall be operated in a manner which protects against surface and groundwater contamination. The facility operator shall implement the groundwater monitoring plan approved by the Colorado Department of Health and the Weld County Environmental Protection Services Division. The analytical method and statistical evaluation of groundwater monitoring data shall comply with Section 2.2.3 (b) and (c) of the Solid and 920638 952068 DEVELOPMENT STANDARDS - LAIDLAW WASTE SYSTEMS (COLORADO) , INC. PAGE 2 Hazardous Waste Disvosal Sites and Facilities Regulations contained in the Colorado Code of Regulations, 6 CCR 1007-2. Carbonate and cation-anion balance shall be included as part of the groundwater monitoring program. The applicant shall also analyze leachate for the following parameters: total organic halides, biochemical oxygen demand total petroleum hydrocarbons, total phenols, pH, and specific conductivity. These are a minimum. The operator may choose to do a more detailed analysis. 9. Any changes or updates to the groundwater monitoring plan or specific groundwater monitoring plan shall be made by the facility operator when requested in writing by the Weld County Environmental Protection Services Division or Colorado Department of Health. A copy of any request for change shall be forwarded to the Department of Planning Services ' staff for review. 1a. The facility shall be operated in a manner to control blowing debris at all times. Operation during windy periods shall be conducted in a manner that controls blowing debris. The working face will be closed to disposal when high wind warning conditions exist as defined in Section 1.2 of the Colorado Department of Health' s Solid Waste Disposal Sites and Facilities Regulations, 6 CCR 1007-2. The following operation measures shall be employed to control blowing or illegally dumped debris: a. Any debris found outside the working face shall be picked up within 24 hours. b. The following shall be patrolled daily by facility staff to pick up all debris and return it to the working face: i. The fence along the perimeter of the Special Review Permit area; ii. Weld County Road 5 between State Highway 7 and Weld County Road 8; iii. Weld County Road 6 between Weld County Roads 5 and 7; iv. State Highway 7 between Weld County Roads 5 and 7. c. The manager of the facility shall respond to requests for picking up debris within 24 hours of notification by Weld County Environmental Protection Services Division personnel. d. A minimum 6-inch solid cover or other cover alternative approved by the Colorado Department of Health and the Weld County Environmental Protection Services Division shall be applied daily to control the 920638 952068 DEVELOPMENT STANDARDS - LAIDLAW WASTE SYSTEMS (COLORADO) , INC. PAGE 3 size of the working face. Cover shall be placed on debris as soon as possible on days when wind is a noticeable problem. e. The working face shall be enclosed on the downwind side(s) with a minimum 12-foot litter screen while accepting waste. An 8-foot litter and access-control fence shall be maintained around the Special Review Permit area. f. During windy periods, which have not reached the threshold to be defined as high wind warning conditions, the size of the working face shall be reduced to a size that eliminates debris escaping the screen. g. The size of the working face shall be reduced to 100 feet in width while accepting waste after dark. 11. Colorado Department of Health Regulations pertaining to Solid Waste Disposal Sites and Facilities. Section 2.2. 7. state: "Disposal sites and facilities that accept putrescible wastes that may attract birds, and which occur within 10,000 feet (3048 meters) of any airport runway used by turbojet. or within 5,000 feet (1523 meters) of any airport runway used by piston-type aircraft shall not pose a bird hazard to aircraft." The facility must be operated in compliance with the approved bird hazard study and mitigation plan. 12. The facility shall be operated in a manner which controls odor. Odors detected off-site shall not equal or exceed the level of fifteen-to-one dilution threshold, as measured pursuant to Regulation 2 of the Colorado Air Pollution Control Regulations. 13. The facility shall be operated in a manner to control fugitive dust at all times. The facility operator shall implement the plan for controlling fugitive dust, as approved by the Weld County Environmental Protection Services Division. Any changes or updates to the plan for controlling fugitive dust shall be made by the facility operator when required in writing by representatives of Weld County. A copy of any request for change shall be forwarded to the Department of Planning Services' staff for review according to Development Standard ( 34. 14. The Special Review Permit site and facility shall be operated in compliance with any required Air Emissions Permit approved by the Air Pollution Control Division of the Colorado Department of Health. 15. The maximum permissible noise level shall not exceed the light industrial limit of 70 dB(A) , as measured according to Section 25-12-102. C.R.S. 16. Adequate toilet facilities, served by an individual sewage disposal system, are required for the facility. The facilities shall be installed in accordance with the Weld County Individual Sewage Disposal and Building Code Regulations. 995=068 DEVELOPMENT STANDARDS - LAIDLAW WASTE SYSTEMS (COLORADO) , INC. PAGE 4 17. The owner and/or facility operator shall comply with the off-site road improvements and maintenance agreement approved by the Board of County Commissioners. 18. The owner and/or facility operator shall maintain an adequate water supply for the disposal site facility. The source of water for construction. operation. drinking, and sanitary facilities shall be approved by representatives of Weld County Environmental Protection Services Division and the Division of Water Resources. 19. The proposed facility shall be operated in compliance with the applicable regulations of the Federal Aviation Administration. 20. The disposal site facility shall be operated in compliance with the requirements of the Mountain View Fire Protection District. Plans for any additional buildings to be constructed on the site shall be submitted to the Fire District prior to beginning construction. 21. All stockpile overburden, soil, and associated materials shall be managed to prevent nuisance conditions. The facility operator shall comply with the reclamation plan approved by the Boulder Valley Soil Conservation District. 22. The facility shall continue to be subject to the terms of Weld County Ordinance No. 164 as it exists or as it may from time to time be amended. 23. The owner or operator shall be responsible for maintaining the approved screening and landscaping plan. 24. Two metal signs shall be posted at the customer entrance. The first sign shall state: "ALL UNCOVERED LOADS SHALL BE CHARGED TWICE THE NORMAL FEE". The second sign shall state: "ABSOLUTELY NO HAZARDOUS MATERIALS, TOXIC SUBSTANCES, SEPTIC, OR LIQUID SLUDGE ACCEPTED." 25. The facility operator shall keep the following records at the facility to be available for County and State review at any reasonable time: a. Quarterly operations inspection reports, completed by the Weld County Environmental Protection Services Division. b. Results of wind, methane, and water quality monitoring. c. Soil liner certification report. d. Any special waste accepted at the facility. 26. The solid waste disposal site and facility plan and monitoring programs are subject to revisions pending the receipt of pertinent data and/or changing site conditions. All requests for revision shall be submitted in 920638 952068 DEVELOPMENT STANDARDS - LAIDLAW WASTE SYSTEMS (COLORADO) , INC. PAGE 5 writing to the Department of Planning Services for review in accordance with Development Standard #34. 27. Lighting provided for security operation an the site shall be designed so that the lighting will not adversely affect surrounding property owners. 28. All phases of the operation must conform to Title 30, Article 20, Part 1, C.R.S. , as amended, and regulations promulgated thereunder, for Solid Waste Disposal Sites and Facilities, and Subtitle D of the Resource Conservation and Recovery Act. 29. There shall be no discharge of wastes into any stream, other bodies of water, or adjacent drainage systems without obtaining a National Pollution Discharge Elimination System Permit from the Colorado Department of Health. This Development Standard shall be deemed satisfied as determined by the State of Colorado, Department of Health. 30. The property shall be maintained in compliance with the Geologic Hazard Overlay District requirements. 31. The property owner or operator shall be responsible for complying with the Design Standards of Section 24.5 of the Weld County Zoning Ordinance. 32. The property owner or operator shall be responsible for complying with the Operation Standards of Section 24.6 of the Weld County Zoning Ordinance. 33. Personnel from Weld County Environmental Protection Services Division. Colorado Department of Health, and Weld County Department of Planning Services shall be granted access onto the property at any reasonable time in order to ensure the activities carried out on the property comply with the Development Standards stated herein and all applicable Weld County Regulations. 34. The Special Review area shall be limited to the plans shown herein and governed by the foregoing Standards and all applicable Weld County Regulations. Major changes from the plans or Development Standards as shown or stated shall require the approval of an amendment of the Permit by the Weld County Planning Commission and the Board of County Commissioners before such changes from the plans or Development Standards are permitted. Any other changes shall be filed in the office of the Department of Planning Services. 35. The property owner or operator shall be responsible for complying with all of the foregoing Development Standards. Noncompliance with any of the foregoing Development Standards may be reason for revocation of the Permit by the Board of County Commissioners. 920638 952068 t'` s"%, UNITED STATES ENVIRONMENTAL PROTECTION AGENCY LREGION VIII Za. 999 18th STREET - SUITE 500 - RECEIVED DENVER, COLORADO 80202-2466 AUG 3 0 1995 AUG 17 1995 DOTY & ASSOC. Ref: 8HWM-ER ATTACHMENT 6 REMOVAL ACTION REMEDY SELECTION SUBJECT: Colorado School of Mines Research Institute Site, Golden, Jefferson County, Colorado. FROM: Mike Zimmerman, OSC 'ryl‘,-C).-e Emergency Response Branch ti TO: Robert L. Duprey, Director Hazardous Waste Management Division THROUGH: Cheryl A. Crisler, Chief p.esponse Section John R. Giedt, Chief /art Emergency Response Branch Category of Removal: T' e-Critical, Non-NPL, Continuation of Initial Removal Action, EPA Fund-Lead Site ID#: N8 Case # C920049 I. PURPOSE The purpose of this decision document is to request and document approval of the Colorado School of Mines site (Site) selected Removal Action - classification of contaminated soils as "special solid waste" and off-site disposal of contaminated soil to an approved solid waste disposal facility. This remedy was recommended in the Removal Action Option Analysis (RAOA) submitted by Potentially Responsible Parties (PRPs) in compliance with the Unilateral Administrative Order (UAO) , Docket No. CERCLA-VIII-95-06, issued on December 15, 1994, by the United States Environmental Protection Agency (EPA) . II. SITE CONDITIONS AND BACKGROUND A. Site Description Refer to the previous ACTION MEMORANDUMS dated April 23 , 1992, July 7, 1992, July 1, 1993 and Polrep No. 8, dated February 23 , 1994, for detailed descriptions of Site characteristics and removal activities . 1v Printed on Recycled Paper 952068 1. Removal Actions Taken to Date By EPA: Refer to the previous ACTION MEMORANDUMS dated April 23, 1992, July 7, 1992 , and July 1, 1993 , for a description of early removal actions taken by EPA. EPA continues to store, pending disposal, approximately 15, 000 c.y. of excavated contaminated materials on a clay-lined pad constructed on the western edge of the Site. The contaminated stockpile was sprayed with fixant to prevent migration of fugitive dust from the Site. Custody of eight-hundred (800) drums located Building No. 2 has been returned to CSM for appropriate disposal. EPA completed testing of 50, 000 gallons of contaminated water in storage tanks (frac) and discharged 40, 000 gallons into the Publicly Owned Treatment Works (POTW) located in Golden, Colorado. The remaining contaminated liquids were drained into a sump area protected by a berm on the southwest corner of the stockpile. After evaporation of excess water, the residuals were left on the stockpile. Drainage improvements were also constructed to prevent further erosion of the embankment. Subsequent to these actions, EPA sampled the stockpile for waste characterization purposes and developed a risk assessment to document the public health threat posed by the stockpile. 2 . Removal Actions By Potentially Responsible Parties: The Potentially Responsible Parties developed, in compliance with the UAO, a Removal Action Options Analysis, to study alternative disposal options . Submitted on June 12 , 1995 , the detailed RAOA evaluated on-site, near on-site, and off-site disposal alternatives, and recommended that EPA select off-site disposal to a solid waste landfill as the Removal Action for the Site. III. PROPOSED REMOVAL ACTIONS A. Proposed Remedy Selection Description The RAOA identified several disposal options for consideration and evaluated them against the following removal criteria: 1) effectiveness; 2) implementability, 3) cost, and 4) community acceptance. The criteria stated were consistent with the National Contingency Plan (NCP) . Upon reviewing the RAOA, EPA found the evaluations of the no action/institutional controls, on-site and near-site disposal options (Alternatives 1-3) to be incomplete 952068 3 and deficient in several respects. Because of a lack of information concerning the subsurface geology and hydrology beneath the waste pile and in the surrounding area, it is at best uncertain whether an on-site or near-site remedy would be protective of human health and the environment in the long term, would be cost- effective, and could meet all of the Applicable or Relevant and Appropriate Requirements for such a repository. Implementation of the near-site alternative would require that the facility obtain a Certificate of Designation for creation of a solid waste landfill. Since this would require both state and local approval, the administrative feasibility for implementation of this alternative is less certain than for the other alternatives, and in any event, delays in completion of the Removal Action. For the above- mentioned reasons, Alternatives 1-3 were excluded from consideration. A variety of off-site alternatives were identified in the RAOA (Alternatives 4A, 4B, and 4C) . Off-site disposal at Envirocare (4A) and off-site disposal in a solid waste landfill (4C) were determined to be more desirable than off-site disposal at Umetco (4B) in terms of administrative implementability. The status of Umetco' s waste disposal license is unclear and because of the contentious history surrounding the permitting of Umetco, final resolution of the issues surrounding Umetco' s license may not occur in the short . term. In theory, disposal at Envirocare is most administratively feasible as all permits are in place. At the time of this writing, however, at least one solid waste disposal facility identified in Alternative 4C has received all of the necessary local and state approvals for disposal of the stockpile material . A notable difference between disposal at Envirocare and disposal at a solid waste landfill is the cost; at approximately $5, 528, 000, Envirocare is more than twice the cost of a solid waste landfill . Additionally, as noted above, community acceptance for disposal at a solid waste landfill was stronger than support for any other alternative. After evaluating the criteria for disposal of "special solid waste" at a solid waste landfill, EPA believes that the solid waste landfill option will be at least as protective and effective and meet ARARs as well as the Envirocare alternative. Given all of these considerations, EPA believes that designation of the stockpile material as "special solid waste" and disposal of the material at a solid waste disposal facility is the appropriate response action 952068 4 for the Site. EPA expects the selected solid waste disposal facility to have in place appropriate institutional controls - including access restrictions, engineering safeguards, and waste management practices to ensure protection of public health, safety and the environment. The solid waste disposal facility selected must comply with all • applicable regulations pertaining to solid waste disposal sites and facilities. The facility should be able to provide a discrete location within a disposal cell incorporating physical separation barriers for the purpose of preventing commingling of wastes, as well as a leachate collection system and a monitoring well system to protect groundwater resources . Disposal of the stockpile material at a solid waste landfill is consistent with many EPA mining site remedies . Capping in place for large volume - low toxicity waste piles is similar to Alternative 4C with the difference being that the stockpile material will be transported from an adverse location to an approved landfill. The State of Colorado has been delegated RCRA and Solid Waste regulatory authorities by EPA. The stockpile material tested negative for RCRA hazardous waste characteristics and contains no known RCRA listed waste, thus eliminating it as a hazardous waste. Further, the State of Colorado is recognized as an "agreement state" by the Nuclear Regulatory Commission, with regulatory authorities over all radioactive material control programs within the borders of Colorado, except those at federally controlled facilities . Since regulatory purview of radioactive materials defaults to the State of Colorado, a waste classification review of stockpile materials has been conducted by the Radiation Control Division, Colorado Department of Public Health and Environment (CDPHE) . Along with a review from the Hazardous Waste Management Division' s Solid Waste Section' s, CDPHE concurs with "special solid waste" designation for the stockpile material (see attachment) . As part of this Removal Action, EPA believes that the Administrative Record clearly supports the use of U.S. Highway 6 as most appropriate transportation route for stockpile materials rather than alternative route eastbound through the 12th Street Historic District and the Golden commercial district. 952068 5 2 . Project Schedule The projected order of work and tentative schedule of activities are as follows : 1. Work Plan for Selected 60 Days from Selection of Removal Action Option Removal Action Option by EPA 2 . Initiation of Selected 30 Days from Approval of Removal Action Option Detailed Work Plan 3 . Completion of Selected April 3, 1996 Removal Action Option RECOMMENDATION This decision document represents the selected remedy to complete the Removal Action for the Colorado School of Mines Research Institute Site, developed in accordance with CERCLA, as amended, and is not inconsistent with the NCP. This decision is based on the Administrative Record for the Site. Conditions at the Site meet the NCP section 300 .415 (b) (2) criteria for the Removal and documents your approval of the proposed Removal Action. I recommend your approval of the decision to classify the material as "special solid waste" with disposal at an approved solid waste disposal facility. Approve: �/��"/l/ Date:B7/f_< Robert L. Du rector Disapprove: Date: Robert L. Duprey, Director 952068 ATTACHMENT 7 STATE OF COLORADO Roy Romer,Governor Patti Shwayder,Acting Executive Director $0 �otgpy, Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr.S. Laboratory Building t G:4 Denver,Colorado 80222-1530 4210 E.11th Avenue RECEIVED *ta96• Phone(303)692-2000 Denver,Colorado 80 2 2 0-3 71 6 (303)691-4700 Colorado Department SEP 0 1995 of Public Health and Environment August 30, 1995 DOTY & ASSOC. Weld County Board of Commissioners 915 10th Street Greeley, Colorado 80632 Re: Disposal of Soil from CSMRI-Creekside Site Laidlaw's Denver Regional Landfill (South) Weld County, Colorado Dear Commissioners: This letter is for your review and consideration regarding Laidlaw's Denver Regional Landfill (South) disposal facility located in Weld County, near Erie, Colorado. Laidlaw must obtain written approval from both Weld County and the Colorado Department of Public Health and Environment for the receipt and final disposal of the material in Laidlaw's August 1, 1995 proposal and supplemental information dated August 24, 1995. The Radiation Control Division has reviewed Laidlaw's August 1, 1995 proposal and supplemental information dated August 24, 1995, to transfer radioactive material, for final disposal, from the Colorado School of Mines Research Institute - Creekside Site to Laidlaw's Denver Regional Landfill (South) facility located in Weld County, near Erie, Colorado. The material in Laidlaw's proposal are the contaminated stockpiled soils which are subject to the U.S. Environmental Protection Agency's Unilateral Administrative Order No. CERCLA-VIII-95-06; hereafter referred to as the "CSMRI-Creekside stockpiled soils". The volume of the CSMRI- Creekside stockpiled soils has been estimated to be approximately 20,000 cubic yards. Both the Radiation Control Division and the Hazardous Materials and Waste Management Division's Solid Waste Section have reviewed Laidlaw's proposal and supplemental information. The CSMRI-Creekside stockpiled soils require "special approval" for final disposal at a facility such as Laidlaw's Denver Regional Landfill (South). The Radiation Control Division's review has determined that: 1. the CSMRI-Creekside stockpiled soils have been adequately characterized by the U.S. Environmental Protection Agency and the State of Colorado; 952068 Weld County Commissioners August 30, 1995 Page 2 of 3 2. the CSMRI-Creekside stockpiled soils are not low-level radioactive waste; therefore the materials are not subject to the specific disposal requirements contained in Part 14 of the Colorado Rules and Regulations pertaining to Radiation Control (6 CCR 1007-1); and 3. the handling and disposal procedures and commitments on the part of Laidlaw meet the human health and environmental standards for protection against radiation contained in Part 4 of the Colorado Rules and Regulations pertaining to Radiation Control (6 CCR 1007-1), and are therefore acceptable with the following condition: a. The U.S. Environmental Protection Agency and/or the State of Colorado may require different methods to physically separate the CSMRI-Creekside stockpiled soils from other waste in the disposal cell. Laidlaw shall work with the U.S. EPA and the State of Colorado to develop a mutually agreed upon waste separation/segregation plan. Laidlaw's risk assessment evaluation indicates that an extremely low exposure associated with this operation would be to occupants if residences were allowed on the site after closure of the landfill operation. To prevent possible exposure, the recorded notation on the deed required under Subsection 3.4.1 of the Colorado Solid Waste Regulations (6 CCR 1007-2) shall include a restriction that the site may not be developed for residences. Also, in accordance with Subsection 3.6.1(A)(7), post-closure use of the property shall not disturb the integrity of the landfill containment and monitoring systems. Based upon our technical and regulatory reviews, the Radiation Control Division and the Ha7nrdous Materials and Waste Management Division recommend that Laidlaw's Denver Regional Landfill (South), located in Weld County, be approved with the above stated conditions for the one-time special approval to receive and dispose of the CSMRI-Creekside stockpiled soils. We do not believe that an amendment to Laidlaw's Certificate of Designation is necessary for the one-time special approval of this material. Please note that the Colorado School of Mines Research Institute ("CSMRI"), under their Colorado Radioactive Materials License#617-01,must obtain authorization from this Department to transfer the material from their facility to another. Should CSMRI elect to transfer this material to Laidlaw's Denver Regional Landfill (South), additional coordination regarding pending issues (e.g., transportation, air monitoring, final procedures, etc.) will need to be conducted between Laidlaw and this Department and the U.S. Environmental Protection Agency. 952068 Weld County Commissioners August 30, 1995 Page 3 of 3 If you have any questions or need further information regarding this recommendation, please contact either Roger Doak (CDPHE-HMWMD) at 692-3437 or Greg Brand (CDPHE-RCD) at 692-3064. Sincerely, m _rnaji lenn F. Mallory Solid Waste Section Clue Ha�zardous�Materials & Waste Management Division 7 Donald H. Simpson Uranium & Special Projects Unit Leader Radiation Control Division cc: Weld County Planning Department Trevor Jiricek, Weld County Health Department Rick Hoffman, Laidlaw Waste Systems, Inc. Brenda Lenz, Laidlaw Waste Systems, Inc. Ben Doty,,Doty & Associates Mike Zimmerman, U.S. EPA - Region VIII Suzanne Bohan, U.S. EPA - Region VIII Asimakis Iatridis, Colorado School of Mines Rick Brown, CDPHE - HMWMD Gultekin Savci, Steffen Robertson and Kirsten 952068 Hello