Attachment_D-8_(4_of_4)_LA-UR-09-8180_Inv._Work_Plan_DP_Site_Agg._Area_Delayed_Sites,_Rev_1_DPWS.pdf

LA-UR-09-8180

December 2009

EP2009-0660

Investigation Work Plan for Delta Prime Site Aggregate Area Delayed Sites, Revision 1

EDITED FOR EXECUTION PURPOSES

RFP-0000300

Prepared by the Environmental Programs Directorate

Los Alamos National Laboratory, operated by Los Alamos National Security, LLC, for the U.S. Department of Energy under Contract No. DE-AC52-06NA25396, has prepared this document pursuant to the Compliance Order on Consent, signed March 1, 2005. The Compliance Order on Consent contains requirements for the investigation and cleanup, including corrective action, of contamination at Los Alamos National Laboratory. The U.S. government has rights to use, reproduce, and distribute this document. The public may copy and use this document without charge, provided that this notice and any statement of authorship are reproduced on all copies.

LA-UR-09-8180

EP2009-0660

Investigation Work Plan for Delta Prime Site Aggregate Area Delayed Sites, Revision 1

December 2009

EDITED FOR EXECUTION PURPOSES

Responsible project leader:

Signed Copy on File

Printed Name Signature Title Organization Date

Responsible representative:

File

Responsible DOE representative:

File

IWP DP Site Aggregate Area, Revision 1

EP2009-0660 v December 2009

EXECUTIVE SUMMARY

The DP Site Aggregate Area is located near the eastern perimeter of the Los Alamos townsite within Technical Area 21 (TA-21) of the Los Alamos National Laboratory (the Laboratory).

In 2005, investigations of Consolidated Unit 21-004(b)-99, Solid Waste Management Unit (SWMU) 21-011(b), and Consolidated Unit 21-022(b)-99 were approved for deferred action until collocated active/occupied buildings, Laboratory processes, and/or utilities were removed and/or taken out of service. These sites consist of a former outfall area, aboveground storage tanks, sumps, and industrial waste lines that transferred DP West and DP East industrial/radioactive liquid wastes to Material Disposal Area (MDA) T or building 21-257 for treatment.

This Delayed Sites Investigation Work Plan describes the operational history, evaluates existing data, and describes the removal of the sumps, waste lines and aboveground storage tanks and sampling associated with accessible portions of Consolidated Unit 21-004(b)-99, SWMU 21-011(b), and Consolidated Unit 21-022(b)-99. The footprints of former DP West buildings 21-003 and 21-004, a pipeline that connected former building 21-012 to MDA T, and structures within MDA T but outside the nuclear environmental site (NES) area boundary will also be investigated.

DP West buildings 21-002, 21-005, 21-150, and their connecting hallways as well as all buildings at DP East are still in place, limiting access to fully investigate these areas. Therefore, complete investigations of these areas will be delayed until the buildings are removed. TA-21 building decontamination and demolition (D&D) campaigns are currently underway. Within 30 working days of D&D debris removal, letter work plans will be submitted for building footprint investigations following the sampling and analysis protocols outlined in this work plan.

The MDA T sites located outside of the NES area boundary include 12 areas of concern (AOCs) and 15 SWMUs previously investigated and documented with a New Mexico Environment Department approved investigation report. These sites are grouped by the waste treatment plant they were associated with: former building 21-035 or current building 21-257. This work plan describes the removal of the structures remaining at these sites, verification of previous structure removals, and additional soil sampling. Building 21-257 will be removed in a future D&D campaign, therefore, investigations within the building footprint, will be delayed until building 21-257 is removed.

A Phase II work plan will be developed upon completion of the activities outlined in this work plan, the D&D activities, and the activities outlined in the D&D building footprint letter work plans. The Phase II work plan will utilize data from this investigation and building footprint investigations to recommend additional investigations to define the nature and extent of contamination at Consolidated Unit 21-004(b)-99, SWMU 21-011(b), Consolidated Unit 21-022(b)-99, and sites at MDA T outside the NES area boundary.

EP2009-0660 vii December 2009

CONTENTS

1.0 INTRODUCTION

1.1 Work Plan Overview

1.2 Work Plan Objectives

1.3 Phased Approach of Field Activities

1.4 Data Overview

2.0 SITE CONDITIONS

2.1 Surface Conditions

2.1.1 Land Use

2.2 Subsurface Conditions

2.3 Conceptual Site Model

2.3.1 Potential Contaminant Sources

2.3.2 Potential Contaminant Transport Mechanisms

2.3.3 Potential Receptors

2.3.4 Cleanup Standards

3.0 DP SITE AGGREGATE AREA BACKGROUND

4.0 CONSOLIDATED UNIT 21-004(b)-99, WASTE LINES, OUTFALL, AND OVERFLOW

HOLDING TANKS

4.1 Background

4.1.1 Operational History

4.1.2 Summary of Releases

4.1.3 Current Site Usage and Status

4.2 Summary of Previous Investigations, Site Data, and Scope of Activities for Consolidated Unit 21-004(b)-99

4.2.1 Summary of Previous Investigations

4.2.2 Site Data

4.2.3 Scope of Activities

5.0 SWMU 21-011(B), ACID WASTE SUMP AND LINES

5.1 Background

5.1.1 Operational History

5.1.2 Summary of Releases

5.1.3 Current Site Usage and Status

5.2 Summary of Previous Investigations, Site Data, and Scope of Activities for SWMU 21-011(b)

5.2.1 Summary of Previous Investigations

5.2.2 Site Data

5.2.3 Scope of Activities

6.0 CONSOLIDATED UNIT 21-022(B)-99, INDUSTRIAL WASTE LINES AND SUMPS

6.1 Background

6.1.1 Operational History

6.1.2 Summary of Releases

6.1.3 Current Site Usage and Status

6.2 Summary of Previous Investigations, Site Data, and Scope of Activities for Consolidated

December 2009 viii EP2009-0660

Unit 21-022(b)-99

6.2.1 Summary of Previous Investigations

6.2.2 Site Data

6.2.3 Scope of Activities

7.0 SWMUs AND AOCs LOCATED WITHIN MDA T BUT OUTSIDE OF THE NES AREA

BOUNDARY

7.1 Background

7.1.1 Operational History

7.1.2 Summary of Releases, Transport Mechanisms, and Potential Receptors

7.1.3 Current Site Usage and Status

7.2 Summary of Previous Investigations, Site Data, and Scope of Activities for Building 21-035 Area at MDA T

7.2.1 Summary of Previous Investigations

7.2.2 Summary of Data

7.2.3 Scope of Activities

7.3 Summary of Previous Investigations, Site Data, and Scope of Activities for Building 21-257 Area at MDA T

7.3.1 Summary of Previous Investigations

7.3.2 Summary of Data

7.3.3 Scope of Activities

8.0 INVESTIGATION METHODS

8.1 Establish Sampling Locations

8.2 Geodetic Surveys

8.3 Surface Sampling

8.4 Subsurface Sampling

8.4.1 Hollow-Stem Auger

8.4.2 Hand Auger

8.4.3 Split-Spoon Sampling

8.4.4 Borehole Abandonment

8.5 Excavation

8.6 Chain of Custody for Samples

8.7 Field-Screening Methods

8.7.1 Radiological Field Screening

8.7.2 Organic Vapor Field Screening

8.7.3 Quality Assurance/Quality Control Samples

8.8 Laboratory Analytical Methods

8.9 Health and Safety

8.10 Equipment Decontamination

8.11 Investigation-Derived Waste

8.12 Removal Activities

9.0 MONITORING AND SAMPLING PROGRAM

9.1 Vapor Monitoring

9.2 Groundwater

9.3 Sediment and Surface Water

10.0 SCHEDULE

EP2009-0660 ix December 2009

11.0 REFERENCES AND MAP DATA SOURCES

11.1 References

11.2 Map Data Sources

Figures

Figure 1.0-1 TA-21 and surrounding land holdings Figure 1.0-2 DP Site Aggregate Area and MDA T sites addressed in this work plan Figure 4.1-1 Proposed sampling at Consolidated Unit 211-004(b)-99 and SWMU 21-011(b) aboveground storage tanks, former outfall, sump, and piping Figure 6.1-1 Proposed sampling at Consolidated Unit 21-002(b)-99, industrial waste lines and sumps Figure 7.2-1 Proposed sampling at former building 21-035 area at MDA T Figure 7.3-1 Proposed sampling at building 21-257 area at MDA T

Tables

Table 1.0-1 SWMUs, AOCs, and Consolidated Units Addressed in This InvestigationWork Plan Table 2.3-1 Soil Screening Levels for Chemicals Table 2.3-2 Screening Action Levels for Radionuclides Table 4.2-1 Proposed Sampling at Consolidated Unit 21-004(b)-99, Aboveground Storage Tanks and Former Outfall Table 5.2-1 Proposed Sampling at SWMU 21-011(b), Acid Waste Lines and Sump Table 6.2-1 Proposed Sampling at Consolidated Unit 21-022(b)-99, Industrial Waste Lines and

Sumps Table 7.2-1 Proposed Sampling at Former Building 21-035 Area at MDA T Table 7.3-1 Proposed Sampling at Building 21-257 Area at MDA T Table 8.0-1 Summary of Investigation Methods Table 8.0-2 Analytical Methods for Surface and Subsurface Soil/Tuff Samples Table 10.0-1 Proposed Schedule for Delayed Sites Investigation Reports and Letter Work Plans

Appendixes

Appendix A Acronyms and Abbreviations, Metric Conversion Table, and Data Qualifier Definitions

Appendix B Management Plan for Investigation-Derived Waste

Plate

Plate 1 Overall sampling plan for DP Site Aggregate Area Delayed Sites

EP2009-0660 1 December 2009

1.0 INTRODUCTION

Los Alamos National Laboratory (LANL or the Laboratory) is a multidisciplinary research facility owned by the U.S. Department of Energy (DOE) and managed by Los Alamos National Security, LLC. The Laboratory is located in north-central New Mexico, approximately 60 mi northeast of Albuquerque and 20 mi northwest of Santa Fe. The Laboratory site covers 40 mi2 of the Pajarito Plateau, which consists of a series of fingerlike mesas separated by deep canyons containing perennial and intermittent streams running from west to east. Mesa tops range in elevation from approximately 6200 to 7800 ft. The location of Delta Prime (DP) Site Aggregate Area with respect to the Laboratory technical areas (TAs) and surrounding land holdings is shown in Figure 1.0-1. DP Site Aggregate Area is shown in Figure 1.0-2.

The solid waste management units (SWMUs), areas of concern (AOCs), and consolidated units addressed in this investigation work plan are potentially contaminated with both hazardous and radioactive components. The New Mexico Environment Department (NMED), pursuant to the New Mexico Hazardous Waste Act, regulates cleanup of hazardous wastes and hazardous constituents. DOE regulates cleanup of radioactive contamination, pursuant to DOE Order 5400.5, “Radiation Protection of the Public and the Environment,” and DOE Order 435.1, “Radioactive Waste Management.” Information on radioactive materials and radionuclides, including the results of sampling and analysis of radioactive constituents, is voluntarily provided to NMED in accordance with DOE policy.

Corrective actions at the Laboratory are subject to the March 1, 2005 June 2016 (modified Feb.

2017), Compliance Order on Consent (the Consent Order). This work plan describes work activities that will be executed and completed in accordance with the Consent Order.

1.1 Work Plan Overview

The DP Site Aggregate Area SWMUs, AOCs, and consolidated units addressed in this Delayed Sites investigation work plan are located in TA-21 of the Laboratory (Figure 1.0-2), described in Table 1.0-1, and listed below. These sites were previously referred to as deferred sites (LANL 2006, 092571.12), and are now referred to as delayed sites to avoid confusion with sites listed in the Consent Order as Deferred Sites. Consolidated Unit 21-004(b)-99, SWMU 21-011(b), and Consolidated Unit 21-022(b)-99 are part of the industrial waste lines, which served DP West and DP East. This work plan also addresses a former waste line that connected former building 21-012 to MDA T. The remaining SWMUs/AOCs listed below are located within Material Disposal Area (MDA) T, but outside the nuclear environmental site (NES) boundary (Figure 1.0-2).

Sites associated with the DP West and DP East industrial waste lines:

• Consolidated Unit 21-004(b)-99,

• SWMU 21-011(b), and

• Consolidated Unit 21-022(b)-99.

Sites within MDA T, but outside the NES area boundary and associated with former building 21-035:

• SWMU 21-010(a),

• SWMU 21-010(b),

• SWMU 21-010(c),

• SWMU 21-010(d), December 2009 2 EP2009-0660

• SWMU 21-010(e),

• SWMU 21-010(f),

• SWMU 21-010(g),

• SWMU 21-010(h),

• AOC C-21-002,

• AOC C-21-010,

• AOC C-21-028(a),

• AOC C-21-034,

• AOC C-21-035,

• AOC C-21-036, and

• AOC C-21-037.

Sites within MDA T, but outside the NES area boundary and associated with building 21-257:

• SWMU 21-011(a),

• SWMUs 21-011(d and e),

• SWMUs 21-011(f and g),

• AOC 21-011(h),

• SWMU 21-011(i),

• SWMU 21-011(j),

• AOC 21-001,

• AOC C-21-005,

• AOC C-21-007, and

• AOC C-21-033.

Details of previous investigations and historical data for the MDA T sites are provided in the historical investigation report (HIR) appendix of the investigation work plan for MDA T (LANL 2004, 085641), Appendix B) and the MDA T Investigation Report (LANL 2006, 094151). This work plan addresses the sites using the available information from previous field investigations or removal actions to evaluate current conditions.

Section 1 gives an overview of the sites addressed, the objectives of this work plan, the field activities approach, and data overview. Section 2 presents the surface and subsurface conditions of the DP Site Aggregate Area, as well as the conceptual site model. Section 3 provides a summary of the background of TA-21. Sections 4 through 7 include background information on operational history and summary of releases; current site usage and status of the sites; summaries of previous investigations and data; and presents the scope of activities for Consolidated Unit 21-004(b)-99, SWMU 21-011(b), and Consolidated Unit 21-022(b)-99 and sites at MDA T outside of the NES. Section 8 provides investigation methods for field activities. Section 9 addresses the monitoring and sampling program. Section 10 gives the schedule of the investigation report. Section 11 provides the references and map data sources. Appendix A of this work plan includes a list of acronyms and abbreviations, a metric conversion table, and data qualifier

EP2009-0660 3 December 2009 definitions. Appendix B describes the management of investigation-derived waste (IDW) and includes waste-volume calculations.

1.2 Work Plan Objectives

The objective of the investigation is to remove inactive structures related to the sites, where appropriate, and to collect confirmatory sampling after removing the structures. At the MDA T sites, structures will be removed or verified to have been previously removed and then sampled underneath. The sites at MDA T have been previously investigated and the resulting investigation report has been approved by NMED (NMED 2007, 095411). At the DP East and DP West sites, after structure removal, the objective is to define the nature and extent of contamination associated with these sites.

To accomplish the objectives, this work plan

• presents background information,

• summarizes previous investigations of the sites or, if applicable, provides reference to where this information and data can be found,

• describes proposed sample collection and field activities, and

• identifies and proposes appropriate methods and protocols for collecting, analyzing, and evaluating data to finalize the characterization of these sites.

1.3 Phased Approach of Field Activities

The selection of sampling locations was dependent upon the availability and quality of documentation of past activities, operational history, the degree of prior characterization, and the accessibility of each site.

Site conditions may indicate the need to refine the proposed sampling approach once field activities have begun. The individual site sampling approach is discussed in Sections 4 through 7.

Piping, tanks, and a sump will be removed in conjunction with the investigation activities at Consolidated Unit 21-004(b)-99, SWMU 21-011(b), and Consolidated Unit 21-022(b)-99. Former pipe tunnels and building footprints will be sampled at former buildings 21-003 and 21-004. Piping, tanks, and any remaining underground structures located within MDA T but outside the NES area boundary will be removed or verified to have been previously removed in conjunction with the investigation activities. A pipe that connected former building 21-012 and MDA T will also be investigated. Buried structures/pipes that are found will be removed and inspected for signs of leakage and to determine the optimum locations for sampling beneath them. Trenching will be used to verify buried structure/piping locations. Radiological surveys will be completed in trenches excavated to remove piping and subsurface structures at applicable sites around building 21-257, and at the former outfall area at Consolidated Unit 21-004(b)-99.

Decontamination and demolition (D&D) of DP West buildings 21-002, 21-005, 21-150, and their connecting hallways as well as all buildings at DP East will be conducted concurrently with the investigations and corrective actions outlined in this work plan. The D&D program and Waste and Environmental Services will coordinate their activities to meet both program objectives. During D&D, detailed field observations will be conducted to document the location and condition of subsurface piping, drains, sumps, tanks, and other structures, as well as areas that exhibit elevated field-screening results during the removal process. Radiological surveys will be conducted in the footprints of removed structures and the results will be used to plan investigations of the building’s footprints. Letter work plans will be developed for building footprint investigations as soon as D&D is complete. The letter work plans will provide text, tables, and figures outlining the technical approach to the investigations and reference

December 2009 4 EP2009-0660 protocols and methods outlined in this work plan. The letter work plans will be implemented as quickly as possible to allow incorporation of the information in the planning activities for future investigations.

Analytical data collected in accordance with this work plan and from additional structure footprint investigations will be evaluated and used in the planning of future focused investigations. The Phase II work plan will be submitted after the D&D of DP West buildings 21-002, 21-005, and 21-150 (including their connecting hallways); DP East buildings 21-152, 21-155, and 21-209; and building 21-257 [SWMU 21-011(a) and associated AOCs] at MDA T.

1.4 Data Overview

This work plan refers to the available data and proposes sampling activities and analyses to define the nature and extent of contamination at each site.

Samples from previous investigations were analyzed for inorganic chemicals, organic chemicals, and/or radionuclides either on-site by the Chemical Sciences and Technology (CST) Division at the Laboratory, by off-site fixed laboratories, or by both. Data obtained at on-site CST Division laboratories are screening level data and are used only to select sampling locations; these data are not reported. Only data obtained from off-site fixed laboratories (i.e., decision-level data) are used to aid in determining the nature and extent of contamination.

For Consolidated Unit 21-004(b)-99, SWMU 21-011(b), and Consolidated Unit 21-022(b)-99, there are no decision-level data available (see Sections 4.2.2, 5.2.2, and 6.2.2 for more information). For the MDA T sites located outside of the NES, decision-level data are presented in their entirety in the MDA T investigation work plan and investigation report (see Sections 7.2.2 and 7.3.2 for more information regarding data).

2.0 SITE CONDITIONS

2.1 Surface Conditions

Surface conditions for TA-21 are described in Section 3.2 of the Investigation Work Plan for the DP Site Aggregate Area (LANL 2004, 087461, pp. 32-33). It is important to note that boreholes drilled during the 1996-1997 investigation indicated backfill had been placed on the surface throughout MDA T near building 21-035 and in the NES area (LANL 2004, 085641, Appendix D). The area around building 21-257 was not covered with fill since it was in use during that time. This will be taken into account during sampling activities.

2.1.1 Land Use

Currently, land use of the DP Site Aggregate Area is industrial. It is anticipated that the area will remain industrial and will not change in the reasonably foreseeable future, even if transferred to Los Alamos County. However, residential land use is a potential future land-use scenario. Public access is currently limited at TA-21 through physical controls such as fencing.

2.2 Subsurface Conditions

Subsurface conditions for TA-21 are described in Section 3.3 of the investigation work plan for the DP Site Aggregate Area (LANL 2004, 087461, pp. 33–36).

EP2009-0660 5 December 2009

2.3 Conceptual Site Model

The potential contaminant sources, transport mechanisms, and receptors associated with the conceptual site model are described below. The sampling proposed in this work plan uses a conceptual site model to predict areas of potential contamination and to allow for adequate characterization of these areas.

2.3.1 Potential Contaminant Sources

Releases at the sites addressed within this work plan may have occurred as a result of potential leaks from septic systems, storage tanks, waste lines and drains; discharges from outfalls, sumps, waste treatment processes; and spills.

Releases from the piping, aboveground storage tanks, and the sump north of the Tritium Systems Test Assembly (TSTA) [Consolidated Unit 21-004(b)-99 and SWMU 21-011(b)] may have occurred as a result of unintentional spills or leaks and may have resulted in surface and subsurface contamination.

Releases from the outfall north of the TSTA [Consolidated Unit 21-004(b)-99] were the result of Laboratory operations and may have resulted in surface and subsurface contamination.

Releases from the industrial waste lines [Consolidated Unit 21-022(b)-99] may have occurred as a result of leaks and may have resulted in subsurface contamination. Releases from the sumps that were connected to the lines are known to have occurred and resulted in subsurface contamination (LANL 1991, 007529).

Releases from the waste treatment plant buildings 21-035 and 21-257 and associated piping, buried structures, and tanks were a result of accidental spills, leaks, or releases.

Releases from the septic tank and leach field [SWMU 21-010(e)] may have occurred as a result of leaks resulting in subsurface contamination. Discharges to the leach field as a result of normal operations may have resulted in subsurface contamination.

2.3.2 Potential Contaminant Transport Mechanisms

Potential transport mechanisms that may lead to exposure include

• dissolution and/or particulate transport of surface contaminants during precipitation and runoff events;

• vaporization and gaseous diffusion and advection of volatile organic compounds (VOCs) and tritium in air;

• water line breaks resulting in sheet flow;

• preferential flow paths along buried utility lines;

• airborne transport of contaminated surface soil;

• continued dissolution and advective/dispersive transport of contaminants contained insubsurface soil and tuff;

• infiltration of water through the vadose zone;

• disturbance of contaminants in shallow soil and subsurface tuff by construction, D&D, or Laboratory operations;

December 2009 6 EP2009-0660

• biotic perturbation and translocation in subsurface contaminated media including shallow soil; and

• disturbance and uptake of contaminants in shallow soil by plants and animals (bioturbation).

2.3.2.1 Surface Processes

Laboratory operations, construction/D&D of structures, bioturbation, surface water runoff, and wind can disturb contaminants present in shallow soil (0 to 1 ft below ground surface [bgs]). During summer thunderstorms and spring snowmelt, runoff from the mesa top may flow down the hillside and into the ephemeral stream channel in DP Canyon. Soil erosion can vary significantly depending on factors including soil properties, the amount of vegetative cover, the slope of the contaminated area, and the intensity and frequency of precipitation. At TA-21, surface transport of contaminants represents the most dominant transport pathway; however, SWMU 21-011(b) is partially covered by asphalt and Consolidated Unit 21-022(b)-99 is mostly covered by asphalt. The outfall at Consolidated Unit 21-004(b)-99, while it slopes down toward DP Canyon, is heavily vegetated, which impedes erosion and contaminant transport.

MDA T, near former building 21-035, is covered with an undetermined amount of fill and most of the area is vegetated.

2.3.2.2 Subsurface Processes

Studies have shown that infiltration of natural precipitation is quite low across the mesa tops of the Pajarito Plateau. The average annual potential evapotranspiration rates far exceed precipitation rates.

Under these conditions, infiltration events that propagate beneath the root zone are sporadic and occur only when the short-term infiltration rate exceeds the evapotranspiration rate, such as during summer thunderstorms and spring snowmelt. However, these events more commonly produce runoff into neighboring canyons resulting in infiltration rates below the root zone on the order of a few millimeters per year or less for mesa-top sites (Collins et al. 2005, 092028, pp. 2-84-2-88; Kwicklis et al. 2005, 090069).

This slow infiltration rate generally leads to present-day subsurface contaminant migration of only a few meters. Geochemical interactions between the contaminants and the rocks generally act to retard migration further. Therefore, groundwater transport of contaminants through the unsaturated zone to the regional aquifer at a depth of approximately 1280 ft below the mesa top is not likely to represent a dominant pathway for contaminant transport (Koch and Schmeer 2009, 105181).

2.3.3 Potential Receptors

Potential receptors at one or more of the sites include on-site and nearby Laboratory workers, construction/D&D workers, hikers in DP Canyon, plants, and/or animals.

2.3.4 Cleanup Standards

As specified in section VIII.B.1 IX of the Consent Order, soil screening levels (SSLs) will be used as soil cleanup levels unless they are determined to be impracticable or unless values do not exist for the current and reasonably foreseeable future land uses. Human health SSLs for chemicals and screening action levels for radionuclides that may be detected at the sites are provided in Tables 2.3-1 and 2.3-2 for the industrial, construction worker, and residential scenarios. Both SSL’s and SAL’s must meet Industrial and Construction scenario’s.

EP2009-0660 7 December 2009

3.0 DP SITE AGGREGATE AREA BACKGROUND

TA-21 is located on DP Mesa on the northern boundary of the Laboratory and is immediately east-southeast of the Los Alamos townsite. It extends from the mesa top to the stream channels in two adjacent canyons, DP Canyon to the north and Los Alamos Canyon to the south (Figure 1.0-2).

During World War II, the Laboratory was established for the research, development, and testing of the first deliverable nuclear weapon. In 1945, the operations for establishing the chemical and metallurgical properties of the nuclear material necessary to achieve and sustain the nuclear fission reaction were transferred to newly built facilities at TA-21.

DP West operations began in September 1945, primarily to produce metal and alloys of plutonium from the nitrate solution feedstock provided by other production facilities. This procedure involved several acid dissolution and chemical precipitation steps to separate the plutonium and other valuable actinides from the feedstock. A major research objective at DP West was the development of new purification techniques that would increase the efficiency of the separation processes (Christensen and Maraman 1969, 004779). Details of the purification techniques are discussed in the operable unit work plan for TA-21 (LANL 1991, 007529). Other operations performed at DP West included nuclear fuel reprocessing.

In 1977, a transfer of work to the new plutonium facility at TA-55 began, and much of the DP West complex was vacated.

DP East operations also began in September 1945. These facilities were used to process polonium and actinium and to produce initiators (a nuclear weapons component). In 1964, building 21-209 was built to house research into high-temperature and actinide chemistry. Building 21-155 housed the TSTA for developing and demonstrating effective technology for handling and processing deuterium and tritium fuels used in fusion reactors.

TA-21 includes five MDAs: A, B, T, U, and V (Figure 1.0-1). Process wastes, transuranic (TRU) wastes, and liquid wastes were disposed of at the MDAs from the early 1940s until the late 1970s. Details of the disposal methods are presented in the TA-21 operable unit work plan (LANL 1991, 007529). The major contributors to waste streams at TA-21 were plutonium-processing activities. Numerous other chemicals were used for separation techniques and were present in the waste stream. Airborne emissions, including tritium, were released from some of the buildings at DP West and DP East; these releases are also discussed in the TA-21 operable unit work plan (LANL 1991, 007529).

4.0 CONSOLIDATED UNIT 21-004(b)-99, WASTE LINES, OUTFALL, AND OVERFLOW HOLDING

TANKS

4.1 Background

4.1.1 Operational History

Consolidated Unit 21-004(b)-99 (Figure 4.1-1) consists of SWMU 21-004(b), SWMU 21-004(c), and AOC 21-004(d). SWMUs 21-004(b) and (c) are two aboveground stainless steel tanks (structure 21-346) that were installed in 1979. They were used as overflow holding tanks for liquid waste from cooling towers, and Laboratory and radionuclide experimental operations in the TSTA facility (building 21-155). Each tank is 9 ft high and 8 ft in diameter and has a capacity of 3000 gallons (LANL 1990, 007512). Both tanks are currently mounted on steel legs above the surface of an asphalt bermed area. The bermed area has a capacity of approximately 9600 gal. and measures 36 ft long by 18 ft wide. The drain line connected to these tanks, as well as an outfall area that was present in 1965 before the tanks were installed, comprises AOC 21-004(d). The tanks were connected to the existing vitrified clay outfall pipe and

December 2009 8 EP2009-0660 concrete headwall (a small retaining wall placed at the outlet of a stormwater pipe or culvert) by an aboveground 6-in. galvanized pipe that connects to the top of the tanks. The former outfall discharge area was located where the concrete headwall is situated today (Figure 4.1-1).

4.1.2 Summary of Releases

Releases to the former outfall area before the aboveground tanks were installed were a result of Laboratory operations and may have resulted in surface and subsurface contamination. Releases from the piping associated with this consolidated unit may have occurred as a result of leaks and resulted in subsurface contamination. Releases from the tanks may have occurred from unintentional spills or leaks and resulted in surface and subsurface contamination.

4.1.3 Current Site Usage and Status

Currently, all operations have ceased at the buildings associated with this consolidated unit; therefore, the tanks and lines are not in use. The tanks, headwall, former outfall area, and lines are still present.

4.2 Summary of Previous Investigations, Site Data, and Scope of Activities for Consolidated

Unit 21-004(b)-99

4.2.1 Summary of Previous Investigations

In 1988, a sample was collected 2 ft downslope of the headwall from beneath the outfall pipe (LANL 1991, 007529, p. 15-96). Two boreholes were drilled downslope of tanks 21-346 to a total depth of 5 ft bgs in the fall of 1994 (LANL 1996, 054828, pp. 32-33).

4.2.2 Site Data

The last samples collected at this consolidated unit were in the fall of 1994. There are no recent data for this consolidated unit.

The tanks are still present, as well as the pipe connected to the tanks [AOC 21-004(d)] and the former outfall area. Therefore, sampling after structure removal is necessary at this site.

4.2.3 Scope of Activities

The proposed sampling locations at Consolidated Unit 21-004(b)-99 are shown in Figure 4.1-1. On the figure, the red samples address this consolidated unit. Table 4.2-1 provides a summary of the proposed sampling objectives, number of samples proposed, sample locations and depths, and proposed analytical suites. Plate 1 shows the proposed sampling locations for this site in relation to the other sites addressed in this work plan.

Samples will be analyzed for target analyte list (TAL) metals, cyanide, nitrate, perchlorate, organic chemicals (VOCs and semi-volatile organic compounds [SVOCs]), radionuclides (americium-241, isotopic plutonium, isotopic uranium, strontium-90, tritium, and by gamma spectroscopy), moisture, and pH. VOCs will only be analyzed in samples deeper than 0.5 ft bgs. In addition, 20% of all samples will also be analyzed for extended suite consisting of dioxins/furans, explosive compounds, and polychlorinated biphenyls (PCBs) (Table 4.2-1). The locations selected for extended suite analysis are areas with the most potential for contamination; where contaminants had the most potential to be released to the environment (e.g., sumps, sharp bends or connections in piping) or were intentionally discharged

EP2009-0660 9 December 2009

(e.g., outfalls). If field-screening results identify locations with higher readings than those already selected for extended suite analyses, these locations will be analyzed for the extended suite instead.

During structure removal activities, excavation of soil, fill, and/or tuff (including any stained areas) will proceed until media with elevated levels of radionuclides and organic vapors based on field screening has been removed to a maximum depth of 10 ft bgs. Excavating to 10 ft bgs is technically practicable for the excavation equipment. If elevated field-screening results are recorded in the deepest sampling depth proposed for a location, samples will be collected in 5-ft-depth intervals at that location until field-screening results indicate no contamination is present. Additional lateral extent samples may also be collected based on elevated field-screening results, staining, and increasing result trends.

Investigation at Consolidated Unit 21-004(b)-99 will consist of the following activities:

Waste line excavation and sampling. The waste line [AOC 21-004(d)] connecting the acid waste sump [structure 21-223, SWMU 21-011(b)] and the aboveground storage tanks [structure 21-346, SWMUs 21-004(b) and (c)] will be carefully excavated and inspected for evidence of leaks (e.g., field screening; stained soil) prior to removal. Samples will be collected from locations immediately beneath the removed pipe where elevated field-screening results, staining, or breaks/cracks indicate potential releases. If field screening or visual observations do not indicate contamination, samples will be collected from locations beneath the removed pipe at the sump outlet connection to the pipe and 50 ft along the pipe (Figure 4.1-1, locations 1 and 2). At each location, samples will be collected from the depth intervals of 0 to 1.0 ft and 2.0 to 3.0 ft. The zero depth is defined as the ground surface immediately beneath the pipe.

Former outfall investigation. One location will be sampled in the center of the former outfall, 0.5 ft downslope from the outlet of the pipe at the headwall (Figure 4.1-1, location 4). Samples will be collected from the 0- to 0.5-ft, 2.0- to 3.0-ft, and 5.0- to 6.0-ft-depth intervals. Samples will be collected 5 ft to the west and 5 ft to the east of the outfall location (Figure 4.1-1, locations 3 and 5).

One location will be sampled 10 ft directly downslope from the outfall location, one location will be sampled 10 ft to the west, and one location will be sampled 10 ft to the east of this center location (Figure 4.1-1, locations 7, 6, and 8, respectively). Sample locations will be adjusted in the field based on local topography in order to assure the optimal sampling locations. Samples will be collected from locations 3, 5, 6, 7, and 8 at the depth intervals of 0 to 0.5 ft and 2.0 to 3.0 ft.

Radiological survey at former outfall area. To address the area between the northern-most row of outfall sampling locations and the aboveground tanks, alpha and gamma radiation surveys will be completed. In Figure 4.1-1, the east side of the map shows the survey area. Samples will be collected from two depths from a maximum of three elevated field-screening locations (locations to be determined) from depth intervals of 0 to 0.5 ft and 2.0 to 3.0 ft. If no elevated areas are found (i.e., greater than two times area background), no additional samples will be collected in this area.

Aboveground storage tanks [structure 21-346, SWMUs 21-004(b) and (c]). The storage tanks will be removed and inspected for evidence of leaks (e.g., field screening; stained asphalt/soil). After removal of the tanks and asphalt, confirmation samples will be collected below the footprint of each tank (Figure 4.1-1, locations 9 and 10), as well as any apparent infiltration pathways (cracks in the asphalt). At these locations, samples will be collected from the depth intervals of 0 to 0.5 ft,

2.0 to 3.0 ft, and 5.0 to 6.0 ft. Under the tanks, zero depth is defined as immediately below the asphalt layer of the containment area.

December 2009 10 EP2009-0660

5.0 SWMU 21-011(B), ACID WASTE SUMP AND LINES

5.1 Background

5.1.1 Operational History

SWMU 21-011(b) is an acid waste sump (structure 21-223) located approximately 760 ft east of the TA-21 waste treatment plant (building 21-257) and 70 ft northwest of the TSTA (building 21-155) (Figure 4.1-1). The sump is located inside a small metal building (no structure number assigned). In 1965, 4-in. piping was installed to transport acid waste from building 21-155 to the sump (structure 21-223).

From the sump, a 3-in. waste line transported acid waste to the old waste treatment plant/laboratory (building 21-035) (LASL 1968, 089722; Francis 1997, 076126). The sump also connected to a 6-in.

vitrified clay overflow pipe, which discharged to DP Canyon, eventually running into the same area as the discharge from the SWMU 21-024(h) septic system (LASL 1968, 089722). The SWMU 21-024(h) outfall was addressed in the DP Site Phase I and II investigations (LANL 2004, 087461; NMED 2005, 089314;

LANL 2008, 104989).

In 1967/1968, the old waste treatment plant/laboratory (building 21-035) was removed and the sump outlet line was extended to the new waste treatment plant (building 21-257) (LASL 1968, 089723; LASL 1975, 089724). In 1979, the sump overflow pipe was connected to the aboveground stainless steel storage tanks [structure 21-346, Consolidated Unit 21-004(b)-99] (LASL 1979, 089721). In the mid- to late-1980s, two new 4-in. acid waste steel or iron lines (LANL 1988, 087575) were connected from building 21-155 to manhole structure 21-222 to be pumped by the sump (LASL 1977, 089726). The line continues to manhole 21-221.

5.1.2 Summary of Releases

Releases from the piping and sump associated with this SWMU may have occurred as a result of leaks and resulted in subsurface contamination.

5.1.3 Current Site Usage and Status

Currently, all operations have ceased at the buildings associated with this SWMU; therefore, the sump and lines are not in use. The sump and the lines are still present.

5.2 Summary of Previous Investigations, Site Data, and Scope of Activities for SWMU 21-011(b)

5.2.1 Summary of Previous Investigations

This SWMU has not been previously investigated.

5.2.2 Site Data

There are no data for this SWMU.

5.2.3 Scope of Activities

The proposed sampling locations (Numbers 30 through 43 ONLY for this Scope of Work) at SWMU 21- 011(b) are shown in Figure 4.1-1. On the figure, the black samples address this SWMU. Table 5.2-1 provides a summary of the proposed sampling objectives, number of samples proposed, sample locations and depths, and proposed analytical suites. Plate 1 shows the proposed sampling locations for this site in relation to the other sites addressed in this work plan.

EP2009-0660 11 December 2009

Samples will be analyzed for TAL metals, cyanide, nitrate, perchlorate, organic chemicals (VOCs and SVOCs), radionuclides (americium-241, isotopic plutonium, isotopic uranium, strontium-90, tritium, and by gamma spectroscopy), moisture, and pH. In addition, 20% of all samples will also be analyzed for extended suite consisting of dioxins/furans, explosive compounds, and PCBs (Table 5.2-1). The locations selected for extended suite analysis are areas with the most potential for contamination; where contaminants had the most potential to be released to the environment (e.g., sumps, sharp bends or connections in piping) or were intentionally discharged (e.g., outfalls). If field-screening results identify locations with higher readings than those already selected for extended suite analyses, these locations will be analyzed for the extended suite instead.

During structure removal activities, excavation of soil, fill, and/or tuff (including any stained areas) will proceed until media with elevated levels of radionuclides and organic vapors based on field screening has been removed to a maximum depth of 10 ft bgs. Excavating to 10 ft bgs is technically practicable for the excavation equipment. If elevated field-screening results are recorded in the deepest sampling depth proposed for a location, samples will be collected in 5-ft-depth intervals at that location until field-screening results indicate no contamination is present. Additional lateral extent samples may also be

The investigation at SWMU 21-011(b) will consist of the following activities:

Acid waste sump structure 21-223 excavation and sampling. The acid waste sump and associated building will be removed and the area inspected for evidence of leaks (e.g., field screening, stained soil). Samples will be collected from one location in the center of the excavation (Figure 4.1-1, location 14), from the depth intervals of 0 to 1.0 ft, 5.0 to 6.0 ft, and 10.0 to 11.0 ft, with zero depth defined as the floor of the excavation.

Pipeline excavation and sampling. The following pipelines will be located by trenching, removed if found, and samples collected:

The pipelines from buildings 21-155 and 21-152 to the sump structure 21-223. The pipelines will be carefully excavated and inspected for evidence of leaks (e.g., field screening; stained soil) prior to removal. Samples will be collected from locations immediately beneath the removed pipe where elevated field-screening results, staining, or breaks/cracks indicate potential releases. If field screening or visual observations do not indicate contamination, samples will be collected from locations beneath the removed pipe at the sump inlet connection to the pipe, pipe bends, and/or every 50 ft along the pipe (Figure 4.1-1 locations 1–13). At each location, samples will be collected from the depth intervals of 0 to 1.0 ft and 2.0 to 3.0 ft. The zero depth is defined as the ground surface immediately beneath the pipe.

The pipeline from the sump structure 21-223 to the Northeast corner of MDA T to former building 21-035 and building 21-257. The pipeline will be carefully excavated and inspected for evidence of leaks (e.g., field screening; stained soil) prior to removal.

Samples will be collected from locations immediately beneath the removed pipe where elevated field-screening results, staining, or breaks/cracks indicate potential releases. If field screening or visual observations do not indicate contamination, samples will be collected from locations beneath the removed pipe at the sump outlet connection to the pipe, pipe bends, and/or every 50 ft along the pipe (Figure 4.1-1, locations 15-43 30- 43). At each location, samples will be collected from the depth intervals of 0 to 1.0 ft and 2.0 to 3.0 ft. The zero depth is defined as the ground surface immediately beneath the pipe.

December 2009 12 EP2009-0660

6.0 CONSOLIDATED UNIT 21-022(B)-99, INDUSTRIAL WASTE LINES AND SUMPS

6.1 Background

6.1.1 Operational History

Consolidated Unit 21-022(b)-99 consists of SWMUs 21-022(b), 21-022(c), 21-022(d), 21-022(e), and 21-022(g) (Figure 6.1-1). These SWMUs are industrial waste lines and associated underground liquid waste sumps; structure 21-082 [SWMU 21-022(b)], structure 21-084 [SWMU 21-022(c)], structure 21-087 [SWMU 21-022(d)], structure 21-089 [SWMU 21-022(e)], and structure 21-189 [SWMU 21-022(g)].

Structures 21-082, 21-084, 21-087, and 21-089 [SWMUs 21-022(b)-(e)] were located adjacent to the northeast corners of buildings 21-002, 21-003, 21-004, and 21-005, respectively. These brick and concrete sumps were constructed in 1945 and were approximately 5 ft, 4 in. in diameter and 10 ft deep.

Construction drawings show a 2-ft-diameter, 5-ft-deep steel catch basin within each sump (LASL 1946, 089727). The sumps received all of the liquid waste discharges, including the floor drains, janitor sinks, and chilled water overflows, from their respective buildings (Maraman and Christensen 1987, 001453.

p. 5) and subsequently flowed through the industrial waste lines to MDA T for disposal (LASL 1946, 089727). The pipeline connecting the sumps to the buildings was constructed of 6-in. cast iron or steel

(LASL 1957, 089733; LASL 1961, 106966; LASL 1975, 089724; LASL 1976, 089730).

In 1952, the waste treatment plant/laboratory (building 21-035) was constructed at MDA T. A 4-in. extra heavy cast iron (EHCI) waste line was installed north of the old 6-in. iron pipe (which was left in place) (LANL 1990, 007512). The sumps were connected to the new line through 4-in. EHCI pipes; the 6-in.

connections were removed (LASL 1957, 089733). Buildings 21-002, 21-003, and 21-005 had additional 1.5-in. stainless steel raffinate waste (liquid remaining after extraction) lines or citrate waste lines that connected directly to the waste treatment plant/laboratory (building 21-035) (LASL 1957, 089733; LASL 1975, 089724; LASL 1975, 089729; LASL 1975, 089730; LASL 1975, 089731). In 1963, plastic liners were placed inside and grouted to the walls of structures 21-082, 21-084, 21-087, and 21-089 (LANL 1991, 007680, p. 18-37). In the late 1960s, building 21-035 was removed and all 4-in. and 1.5-in. waste lines were extended to the new waste treatment plant building 21-257 (LASL 1968, 089723).

In the early 1960s, a sump [structure 21-189, SWMU 21-022(g)] was constructed of concrete with dimensions of 5 ft, 4 in. in diameter and 12 ft deep (LASL 1960, 106768). It was located off the northwest corner of building 21-150, the plutonium fuel service and development building, which housed plutonium fuels development activities. The sump was connected to the plutonium fuel storage building and the waste treatment plant/laboratory (21-035) by 4-in. EHCI pipes (LASL 1962, 089732). This line was extended to building 21-257 when building 21-035 was removed in 1968.

In 1979 and 1980, all five sumps (structures 21-082, 21-084, 21-087, 21-089, and 21-189) were excavated and removed and disposed of at TA-54 (LANL 1991, 007680, p. 18–40; Blackwell 1980, 085470, p. 2). Contaminated soil was removed around the sumps until further excavation jeopardized the buildings. Some of the removed soil had retrievable levels of plutonium (Blackwell 1980, 085470, p. 2).

The removal of additional soil was deferred to a later date when the buildings or waste lines were decommissioned. All excavated surfaces were sprayed with asphalt undercoating and backfilled with clean soil (LANL 1991, 007680, p. 18-40). The radioactive contamination remaining on the walls and bottoms of the excavation areas was monitored using a zinc sulfide (ZnS) alpha scintillator (Ahlquist 1977, 009080). The depths of the excavation at all five sump locations were approximately 14 to 16 ft bgs (LANL 1991, 007680, p. 18-40).

EP2009-0660 13 December 2009

In the late 1980s, a work order was issued to replace the industrial waste lines in the utility tunnels around the inside perimeter of buildings 21-003 and 21-004. The work was started at building 21-004 in 1988 and ended in 1989. Sludge accounted for 50% of the volume of the pipe and was treated as TRU waste. The waste lines associated with building 21-003 were not replaced (Francis 1995, 076109). Around this same time, an asbestos survey was completed in the pipe tunnels of buildings 21-003 and 21-004 (LANL 2000, 104141). Asbestos covered some of the piping and was found to have fallen on the pipe tunnel floors.

In the early to mid 1990s, dye tests were performed to identify all drains from the buildings and structures at TA-21 and to determine where they terminated. A series of dye tests were performed in buildings 21-03 and 21-004. Dye testing at building 21-004 was successful; all dye reached the expected destination. Dye was not reaching building 21-257, the waste treatment plant, from building 21-003.

Camera equipment was placed into the piping in building 21-003 at the northeast corner of the building;

the piping contained standing water, which appeared to be from a leak or plug in the piping. NMED was notified of the situation on November 30, 1994. Following, NMED requested a Corrective Action Report.

In response, the Laboratory submitted a National Pollutant Discharge Elimination System Permit Release Notification Form, stating a discharge had not been identified and was being reported as a potential concern. The release notification summarized the dye test findings and summarized that there was no indication that liquid had escaped into the environment. A critique of the findings was conducted on December 1, 1994. It was decided to report this incident as an off-normal potential concern pending further investigation (Francis 1995, 076109).

In the early to late 1990s, the north and south ends of buildings 21-003 and 21-004 were removed (Phillips 1993, 026468; LANL 1997, 056587). Buildings 21-002, 21-005, and 21-150 are still present, as well as the hallways connecting these buildings (Plate 1).

6.1.2 Summary of Releases

The sumps and associated waste lines transported liquid wastes generated by Laboratory operations at buildings 21-002, 21-003, 21-004, 21-005, and 21-150 to the waste treatment facility at MDA T.

The sumps were removed in the 1970s (Blackwell 1980, 085470, p. 2; LANL 1991, 007680, p. 18-40).

Alpha-emitting radionuclide contamination was…