Nebraska Ordnance Plant (Former), OU 2 Mead, NE 4/7/1997
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PB97-964304 EPA/541/R-97/143 January 1998 EPA Superfund Record of Decision: Nebraska Ordnance Plant (Former), OU 2 Mead, NE 4/7/1997 ~-+,+--,+- ,#'+'+'-'+'+ lit Woodward-Clyde ~ October 1, 1996 WCC Project 92KW030M Commander u.s. Army Engineer District, Kansas City ATTN: CEMRK-EP-EC (Ms. Rosemary Gilbertson) 700 Federal Building 601 East 12th Street Kansas City, Missouri 64106-2896 Re: Transmittal ofFinal Record ofDecision for Signature Pages Completion For Operable Unit No.2 (Groundwater) Former Nebraska Ordnance Plant, Mead, Nebraska Contract No. DACA41-92-C-0023 Dear Ms. Gilbertson: We are hereby transmitting seven copies ofthe subject document. We understand that after the signature pages have been completed, we will distribute copies ofthe signed document according to the attached distribution list. On September 30, 1996, we transmitted to you 13 pages ofthis document which showed revisions from the draft final document in redline/strikeout format. We also copied the transmittal to Mr. Craig Bernstein ofthe U.S. Environmental Protection Agency and Mr. Troy Bredenkamp ofthe Nebraska Department ofEnvironmental Quality. Electronic facsimile was used to make the transmittals. Please contact us should you have any questions. Very truly yours, Curt Elmore, Ph.D., P.E. OU2 Project Manager Mead Project Manager Enclosure cc: Steve Iverson (CEMRK-ME-H) w/o enc. Craig Bernstein (U.S. Environnmental Protection Agency) 92030\RODLTRJ.ACE 10/01196 9:44AM Woodward.Clyde Consultants - A subsidiary of WOOdward-Clyde Group. Inc 10975 EI Monte. SUite 100 Overland Park. Kansas 66211 (913) 344-1000 Fax (913) 344-1011 DISTRIBUTION LIST (After Signature) OF THE FINAL RECORD OF DECISION OPERABLE UNIT NO.2 FORMER NEBRASKA ORDNANCE PLANT MEAD, NEBRASKA Organization Copies U.S. Army Corps ofEngineers 7 Kansas City District ATTN: CEMRK-EP-EC (Rosemary Gilbertson) U.S. Army Corps ofEngineers Letter ofTransmittal Kansas City District Only ATTN: CEMRK-MD-H (Steve Iverson) U.S. Army Corps ofEngineers 1 HTRW Center ofExpertise ATTN: HTRW Document Distribution (Ric Hines) Nebraska Department ofEnvironmental Quality 1 ATTN: Mr. Troy Bredenkamp University ofNebraska Lincoln 1 Agricultural Research and Development Center ATTN: Mr. Daniell. Duncan U.S. Environmental Protection Agency Region vn 3 Waste Management Division ATTN: Mr. Craig Bernstein Natural Resources District 1 ATTN: Mr. Larry Angle Nebraska Department ofHealth 1 ATTN: Mr. Scott Petersen Lincoln Water System 1 ATTN: Mr. Jerry Obrist University ofNebraska Hazardous Materials Safety Officer 1 ATTN: Mr. Del Weed Nebraska National Guard 1 ATTN: Dave Wunibald 92030\R.ODLTRJ.ACE 10/01196 9:00AM Page 1 of 1 OU2 Record ofDecision Former Nebraska Ordnance Plant TABLE OF CONTENTS SectioD f.a&f 1.0 DECLARATION 1-1 2.0 DECISION SUMMARY 2-1 2.1 SITE NAME, LOCATION, AND DESCRIPTION 2-1 2.2 SITE HISTORY AND PREVIOUS INVESTIGATIONS 2-2 2.2.1 Site History 2-2 2.2.2 Previous Investigations 2-4 2.2.3 Summary ofOU2 RI Results 2-6 2.3 COMMUNITY PARTICIPATION 2-7 2.4 SCOPE AND ROLE OF OPERABLE UNIT 2 REMEDIAL ACTION WITHIN THE SITE STRATEGY 2-8 2.5 SUMMARY OF SITE CHARACTERISTICS 2-10 2.6 REMOVAL ACTIONS 2-11 2.7 SUMMARY OF SITE RISKS 2-11 2.7.1 Potential Human Health Risks 2-12 2.7.2 Ecological Risk Assessment 2-14 2.8 SUMMARY OF ALTERNATIVES 2-15 2.8.1 Alternative 1 - No Action 2-19 2.8.2 Alternative 2 - Hydraulic Containment 2-20 2.8.3 Alternative 3 - Focused Extraction 2-20 2.8.4 Alternative 4 - Focused Extraction and Soil Excavation 2-21 2.8.5 Alternative 5 - Focused Extraction with Air Sparging 2-21 2.8.6 Alternative 6 - Focused Extraction with Air Sparging and Soil Excavation 2-22 2.8.7 Alternative 7 - Groundwater Extraction 2-23 2.8.8 Alternative 8 - Groundwater Extraction and Soil Excavation 2-23 2.9 TREATABILITY STIJDIES 2-24 2.10 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 2-24 2.10.1 Introduction 2-24 2.10.2 Comparison ofAlternatives 2-25 2.10.3 Summary 2-31 2.11 THE SELECTED REMEDIAL ACTION 2-32 2.12 STATUTORY DETERMINATIONS 2-33 2.12.1 Protection ofHuman Health and the Environment 2-33 2.12.2 Compliance with ARARs 2-33 2.12.3 Cost Effectiveness 2-40 2.12.4 Utilization ofPermanent Solutions and Innovative Treatment Technologies to the Maximum Extent Practicable 2-40 2.12.5 Preference for Treatment Which Reduces Toxicity, Mobility, or Volume 2-41 2.13 DOCUMENTATION OF SIGNIFICANT CHANGES 2-41 E:\92030\OU2ROD3.ACE OcIO~' 1996 OU2 Record ofDecision Former Nebraska Ordnance Plant TABLE OF CONTENTS SectioQ fa&c 3.0 RESPONSIVENESS SUMMARY 3-1 3.1 OVERVIEW 3-1 3.2 BACKGROUND ON COMMUNITY INVOLVEMENT 3-1 3.3 SUMMARYOF PUBLIC COMMENTS AND AGENCY RESPONSES 3-2 3.3.1 Remedial Alternative Preferences 3-3 3.3.2 Impact on Groundwater Supply 3-9 3.3.3 Reuse ofTreated Water 3-10 3.3.4 Nitrates Contamination 3-11 3.3.5 Current Ecological Impacts 3-12 LIST OF FIGURES After Page FIGURE 1 GENERAL SITE LOCATION MAP 2-1 FIGURE 2 SITE MAP 2-1 FIGURE 3 AREA OF GROUNDWATER WITH CONCENTRATIONS EXCEEDING FINAL TARGET GROUNDWATER CLEANUPGOALS 2-9 FIGURE4 SOIL EXCAVATION AREAS - FORMER NOP LOADLINE I 2-10 FIGURE 5 SOIL EXCAVATION AREAS - FORMERNOP LOAD LINE 2 2-10 FIGURE6 SOIL EXCAVATION AREAS - FORMERNOP LOAD LINE 3 2-10 FIGURE 7 TYPICAL SOIL EXCAVATION SECTIONS 2-10 LIST OF TABLES TABLE 1 RANGEOF COC CONCENTRATIONS DETECTED IN MONITORING WELL SAMPLES 2-6 TABLE 2 FINAL TARGETGROUNDWATER CLEANUPGOALS 2-15 .i E:19203010U2ROD3.ACE 11 OcIO~' /996 aU2 Record ofDecision Former Nebraska Ordnance Plant LIST OF ACRONYMS AFBMD Air Force Ballistic Missile Division AOP advanced oxidation processes ARARs applicable or relevant and appropriate requirements ARDC Agricultural Research and Development Center ATSDR Agency ofToxic Substances and Disease Registry CAMUs corrective action management units CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CERCUS Comprehensive Environmental Response, Compensation, and Liability Information System COCs chemicals ofconcern DNT 2,4 or 2,6-dinitrotoluene DoD Department ofDefense DWEL Drinking Water Equivalent Level DRE destruction and removal efficiency FS Feasibility Study GAC granular activated carbon HA Health Advisory HI Hazard Indices lAG Interagency Agreement MCL Maximum Contaminant Level J.1g/L micrograms per liter NCP National Oil and Hazardous Substances Pollution Contingency Plan NDEQ Nebraska Department ofEnvironmental Quality NOP Nebraska Ordnance Plant NPDES National Pollutant Discharge Elimination System NPL National Priorities List NRD Natural Resources District O&M operation and maintenance OU Operable Unit PCB Polychlorinated Biphenyl RAOs remedial action objectives RCRA Resource Conservation and Recovery Act RDX hexahydro-l ,3,S-trinitro-l ,3,S-triazine RI Remedial Investigation RME Reasonable Maximum Exposure ROD Record ofDecision SARA Superfund Amendments and Reauthorization Act SMCLs Secondary Drinking Water Standards SVE soil vapor extraction SVOCs semi-volatile organic compounds TBCs To Be Considered standards TCE trichloroethene E:\92030\OU2ROD3.ACE October 1996 OU2 Record ofDecision Former Nebraska Ordnance Plant LIST OF ACRONYMS TNB 1,3,5-trinitrobenzene TNT 2,4,6-trinitrotoluene TRC Technical Review Committee TUs temporary units USACE U.S. Anny Corps ofEngineers USATHAMA U.S. Anny Toxic and Hazardous Materials Agency USEPA U.S. Environmental Protection Agency UXO Unexploded ordnance VOCs volatile organic compounds E:\920JO\OU2RODJ .ACE 11 Oaober 1996 OU2 Record ofDecision Former Nebraska Ordnance Plant 1.0 DECLARATION Site Name and Location Fonner Nebraska Ordnance Plant Mead, Nebraska Operable Unit 2: Contaminated groundwater, explosives-contaminated soil which could act as a source of explosives contamination of groundwater and which does not meet the Operable Unit I (OUl) excavation criteria, and soil contaminated with volatile organic compounds (VOCs). Comprehensive Environmental Response, Compensation. and Liability Iofonnation System (CERCUS) Identification Number: NE6211890011 Statement ofBasis and Putwse This decision document presents the selected remedial action for OU2 at the former Nebraska Ordnance Plant (NOP) site near Mead, Nebraska, which was chosen in accordance with the Comprehensive Environmental Response, Compensation. and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA) and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the administrative record file for this site and has been made by the U.S. Environmental Protection Agency (USEPA) and the U.S. Anny Corps of Engineers (USACE), in consultation with the Nebraska Department ofEnvironmental Quality (NDEQ). Assessment ofthe Site Actual or threatened releases of contaminants from this site, if not addressed by implementing the remedial action selected in this Record ofDecision (ROD), may present a current or potential threat to public health, welfare, or the environment Description oftheSelected Remedial Action The former NOP site was used as an ordnance loading, assembly, and packing facility. Operations at the NOP resulted in contamination of soil and groundwater with explosive compounds. Subsequent to NOP operations, a missile facility was constructed and parts were cleaned on the site. These activities resulted in contamination ofgroundwater with trichloroethene (TCE). The site has been divided into three operable units. Operable Unit 1 encompasses the upper 4 feet of soil contaminated with explosive compounds. OU2 includes contaminated groundwater, explosives contaminated soil not remediated during OUI which could act as a source of explosives contamination of groundwater, and soil contaminated with volatile organic compounds. A former on-site landfill and areas ofwaste not previously identified are included in OU3. The remedial action for OU2 addresses one of the principal threats at the site, contaminated groundwater, by containing, extracting, and treating the contaminated groundwater on-site. The major components ofthe selected remedy include: E:\92030\OU2ROD3 .ACE 1-1 October 1996 OU2 Record ofDecision Former Nebraska Ordnance Plant • Hydraulically contain contaminated groundwater exceeding the Final Target Groundwater Cleanup Goals.