PB95-964601
EPA/ROD/R10-95/086
January 1995
EPA Superfund
Record of Decision:
U.S. DOE Idaho National Engineering
Laboratory, Operable Unit 15, ID
12/2/1994
-------
November 1994
OAMO DCMHTUEHT
Of HtMTM UNO WBMPC
DIVISION OF
ENVIRONMENTAL QUALITY
Record of Decision
Declaration for Organic Contamination
in the Vadose Zone
Operable Unit 7-08
Idaho National Engineering Laboratory
Radioactive Waste Management Complex
Subsurface Disposal Area
-------
DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
Organic Contamination in the Vadose Zone (OCVZ)
Subsurface Disposal Area
Radioactive Waste Management Complex
Idaho National Engineering Laboratory
Idaho Falls, Idaho.
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the Organic Contamination
in the Vadose Zone (OCVZ) site located at the Idaho National Engineering Laboratory (INEL).
The remedial action was chosen in accordance with the Comprehensive Environmental Response,
Compensation, add Liability Act (CERCLA) as amended by the Superfund Amendments and
Reauthorization Act (SARA), and is consistent, to the extent practicable, with the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP, 40 CFR Part 300). Information supporting
the selection of the remedy is contained in the Administrative Record for the OCVZ Remedial
Action.
The lead agency of this decision is the U.S. Department of Energy (DOE). The U.S.
Environmental Protection Agency (EPA) approves of this decision and, along with the Idaho
Department of Health and Welfare (IDHW), has participated in the evaluation of final action
alternatives. The IDHW concurs with the selection of the preferred remedy for the OCVZ.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this record of decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.
Implementation of the remedial action selected in this ROD will provide extraction of the organic
contaminants present in the most significant concentrations in the vadose zone beneath and within
the immediate vicinity of the Radioactive Waste Management Complex (RWMC). These extracted
contaminants will be destroyed through treatment at the surface of the RWMC. Extraction and
destruction of the organic contaminants will prevent the long-term contamination of the Snake River
Plain Aquifer (SRPA) above acceptable levels. The selected remedial action is not intended to
address potential contaminants such as radionuclides and metals. These contaminants will be
investigated as part of a comprehensive remedial investigation and feasibility study scheduled to begin
in 19%.
-------
DESCRIPTION OF THE SELECTED REMEDY
This ROD addresses the OCVZ at the RWMC of the INEL. The RWMC has been designated
as Waste Area Group (WAG) 7 of the 10 WAGs currently under investigation at the INEL pursuant
to the Federal Facility Agreement and Consent Order (FFA/CO) between the IDHW, the EPA^ and
the US. Department of Energy Idaho Operations Office (DOE-ID). OCVZ, designated as Operable
Unit (OU) 7-08, is part of WAG 7.
The vadosc zone extends from the ground surface to the top of the SRPA, approximately 580 ft
below the surface. The vadose zone contains volatile organic compounds, primarily in the form of
organic vapors, which have migrated from organic wastes disposed of in pits at the Subsurface
Disposal Area (SDA) of the RWMC. Organic wastes remaining in the pits are not addressed with
the selected remedy described in this ROD. Instead, risks to human health and the environment
associated with these wastes will be evaluated as part of the remedial investigation and feasibility
study which is to begin in 1994 for the disposal pits.
The selected remedy for OCVZ will provide extraction/destruction of organic contaminant
vapors present in the vadose zone beneath and within the immediate vicinity of the RWMC. In
addition, the selected remedy will include monitoring of vadose zone vapor and the SRPA. The
objective of this selected remedy will be to reduce the risks to human health and the environment
associated with the organic contaminants present in the vadose zone and to prevent Federal and state
safe drinking water standards from being exceeded in the future.
The major components of the selected remedy include:
• The installation and operation of five vapor extraction wells (in addition to an existing
vapor extraction well) at the RWMC as part of a first phase effort to extract organic
contaminant vapors from the vadose zone. The selected remedy includes options to
expand the number of vapor extraction wells for potential second and third phases.
Additional system modifications will be evaluated with each phase transition.
• The installation and operation of off-gas treatment systems to destroy the organic
contaminants present in the vapor removed by the extraction wells. Off-gas treatment will
be in the form of catalytic oxidation or an equally effective organic contaminant
destruction technology.
• The addition of soil vapor monitoring wells to monitor the performance of the vapor
extraction wells and verify the attainment of remedial action objectives. Soil vapor
monitoring will also provide information used to evaluate potential modifications to the
selected remedy to continue it beyond the first phase. The expected duration of the first
phase is approximately two years; potential second and third phases would operate for
approximately two years each. The actual duration of each phase is dependent on
elements such as equipment procurement and installation that may be involved with each
potential phase transition.
-------
• The maintenance of institutional controls, which includes: using signs, restricting access,
maintaining fences/barriers, and monitoring the existing production well supplying water
to workers at the RWMC. It is presumed that this level of institutional control will be
maintained at the RWMC through the year 2091.
Organic wastes remaining in the pits could extend the timeframe required to achieve remedial
action objectives using the selected remedy since the remaining organic wastes could act as a "long-
term" source of organic contamination in the vadose zone.
STATUTORY DETERMINATION
The selected remedy is protective of human health and the environment, complies with Federal
and state applicable or relevant and appropriate requirements (ARARs), and is cost-effective. This
remedy uses permanent solutions and alternative treatment technologies to the maximum extent
practicable for this site. The most concentrated areas of organic contaminants present in the vadose
zone will be extracted and destroyed. As such, the selected remedy satisfies the statutory preference
for treatment as a principal element of the remedy.
For those remedial actions that allow hazardous substances to remain on-site. Section 12f (c)
of CERCLA requires that a review of the remedy be conducted within five years after initiation of
the remedial action and at least once every five years thereafter. The purpose of this review is to
evaluate the remedy's performance—to ensure that the remedy has achieved, or will achieve, the
remedial action objectives set forth in the ROD and that it continues to be protective of human
health and the environment. Reviews for the OCVZ selected remedy will be conducted as described
below.
The potential progression of the selected remedy to a second and third phase is dependent on
the ability of the vapor extraction system to achieve the remedial action objectives, i.e., ensure that
risks to future groundwater users are within acceptable guidelines and that future contaminant
concentrations in the aquifer remain below Federal and state safe drinking water standards. During
implementation of the selected remedy at OCVZ, the remedy's performance will be reviewed on a
two year (24 month) cycle, with each phase of operation under the selected remedy expected to last
at least two years. The actual duration of each phase is dependent on elements such as equipment
procurement and installation that may be involved with each transition. The following description
of the review cycle assumes that transitions will occur in a timely fashion every 24 months.
The first review will commence after 18 months of operation under the first phase. Data
accumulated over these 18 months will be analyzed and a decision made by DOE, EPA, and the
IDHW as to what will comprise the second phase of the selected remedy (if a second phase is
necessary to attain remedial action objectives). The selected remedy will continue under first phase
operations up to 24 months, at which time, after the data analysis period, a transition to the second
phase will occur. Data analyzed will be relevant to the attainment of remedial action objectives
(e.g., contaminant recovery rates, equilibrium contaminant concentrations in the vadose zone. etc.).
Considerable engineering judgement will be used in deciding what modifications to the first
phase will be made to continue the selected remedy into a second phase in order to achieve remedial
action objectives. Potential options for continuing the selected remedy into a second phase include:
iii
-------
(1) continuing operation with no changes to the first phase of operation; (2) adding more vapor
extraction wells; (3) extracting from different depths within existing extraction wells; (4) converting
monitoring wells into extraction wells; and (5) adding and/or converting existing wells to passive
venting wells. These options and others not currently identified may be carried out singly or in
combinations, with the intent being to ensure that the selected remedy achieves remedial action
objectives.
The need for additional phases beyond a second phase will be evaluated using the same general
approach as outlined above for the transition between the first and possible second phase. If a
second phase is implemented, then the data evaluation and decision regarding a possible third phase
will begin 18 months into the second phase (i.e., 42 months from the start of the selected remedy)
with the third phase beginning, if necessary, approximately 48 months from the start of the selected
remedy. Potential options for continuing the selected remedy into a third phase would be similar to
those listed above. This type of phased operation will continue through phases lasting 24 months
each until remedial action objectives are achieved. In addition to the 2 year reviews associated with
the potential phases under the selected remedy, a review will be conducted five years after remedial
action objectives have been achieved, and extraction/treatment operations have been discontinued.
IV
-------
Signature sheet for the foregoing OCVZ located in the Subsurface Disposal Area of the Radioactive
Waste Management Complex at the Idaho National Engineering Laboratory Record of Decision
between the U.S. Department of Energy and the Environmental Protection Agency, with concurrence
by the Idaho Department of Health and Welfare.
- JL •
\ohn M. Wilcynski (J 'Date
_lanager
U.S. Department of Energy, Idaho Operations Office
-------
Signature sheet for the foregoing OCVZ Unrated in the Subsurface Disposal Area of the Radioactive
Waste Management Complex at the Idaho National Engineering Laboratory Record of Decision
between the U.S. Department of Energy and the Environmental Protection Agency, with concurrence
by the Idaho Department of Health and Welfare.
DEC 2 "1894
Chuck Clarke Date
Regional Administrator. Region 10
U.S. Environmental Protection Agency
VI
-------
Signature sheet for the foregoing OCVZ located in the Subsurface Disposal Area of the. Radioactive
Waste Management Complex at the Idaho National Engineering Laboratory Record of Decision
between the U.S. Department of Energy and the Environmental Protection Agency, with concurrence
by the Idaho Department of Health and Welfare.
Jerry L. Harris
Director
Idaho Department of Health and Welfare
Date
VII
-------
Viti
-------
CONTENTS
ACRONYMS AND ABBREVIATIONS xiii
1. SITE NAME, LOCATION, AND DESCRIPTION 1
2. SITE HISTORY AND ENFORCEMENT ACnVITIES 3
3. HIGHLIGHTS OF COMMUNITY PARTICIPATION 4
4. SCOPE AND ROLE OF OPERABLE UNIT AND RESPONSE ACTION 7
5. SUMMARY OF SITE CHARACTERISTICS 7
5.1 Geology and Hydrology';"..... 7
5.2 Nature and Extent of Contamination 8
5.3 Results of WE Treatability Studies 16
6. SUMMARY OF SITE RISKS 21
6.1 Human Health Risks 21
6.1.1 Identification of Contaminants of Concern 21
6.1.2 Exposure Assessment 22
6.13 Toxicity Assessment 26
6.1.4 Risk Characterization 26
6.1.5 Uncertainty 30
62 Environmental Concerns 30
6.3 Basis for Response 34
7. DESCRIPTION .OF ALTERNATIVES 34
7.1 Remedial Action Objectives 34
7.2 Summary of Alternatives .-. 36
7.3 Alternative 0—No Action , 37
7.4 Alternative 1—Containment of Vadosc Zone Vapors by Capping 40
7.5 Alternative 2—Extraction/Treatment by WE 40
7.6 Alternative 3—Extraction/Treatment by WE with Vaporization Enhancement ... 44
ix
-------
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES ............ 44
8.1 Threshold Criteria ................. . ............................... 44
8.1.1 Overall Protection of Human Health and the Environment ........... 45
8.1.2 Compliance with ARARs ........... . ......................... 45
82 Balancing Criteria ...................... . .......................... 46
8.2.1 Long-Term Effectiveness and Permanence ........................ 46
8.22 Reduction of Toxicity, Mobility, or Volume through Treatment ........ 47
8.23 Short-Term Effectiveness ...................... v .............. 47
82.4 Implementability ........................... , * ............. . 48-
Cost ........... . ......................................... 48
83 Modifying Criteria ..................... . ........................... 48
83.1 State Acceptance ................................... ........ 49
83.2 Community Acceptance . . .................................... 49
9. SELECTED REMEDY .............. ................................... 49
9.1 Extraction/Treatment by WE Description .............................. 50
92. Remediation Goals ........ ........................................ 50
93 Estimated Costs for the Selected Remedy ............................... 51
10. STATUTORY DETERMINATIONS ................ ...................... 53
10.1 Protection of Human Health and the Environment . . ...................... 53
10.2 Compliance with ARARs ........................................... 53
10.2,1 Chemical-Specific ARARs ........................ ............ 53
10.22 Action-Specific ARARs ........... . .......................... 54
1023 Location-Specific ARARs .......... . . ........ . ............... 55
10.2.4 To-Be-Considered Guidance .................. . ............... 55
103 Cost Effectiveness .............. 1 . . ............................. ... 55
10.4 Use of Permanent Solutions and Alternative Treatment Technologies
to the Maximum Extent Practicable ........ .................. . ......... 55
10.5 Preference for Treatment as a Principal Element .......... ................ 56
11. DOCUMENTATION OF SIGNIFICANT CHANGES ......................... 56
-------
Appendix A—Responsiveness Summary A-l
Appendix B—Public Comment/Response List Index B-l
Appendix C—Idaho National Engineering Laboratory Administrative Record File
Indcxx>f the RWMC Vadose Zone Organics RI/FS Operable Unit 7-08 10/20/94 C-l
FIGURES
1. The Radioactive Waste Management Complex at the INEL 1
2. The RWMC with pits contributing organic contamination to the vadosc zone 4
3. CC14 concentrations in shallow soil vapor at the SDA (1992) 10.
4. Vapor monitoring well locations at the RWMC 12
5. Mean CC14 subsurface vapor concentrations along cross-section A-A* 15
6. Location of wells that have contained perched water at the SDA 17
7. Summary of groundwater analyses for samples taken from the SRPA near SDA ....... 19
8. Total COC emission to the atmosphere over time 25
9. COC concentrations in the SRPA at the SDA boundary over time 25
10. Schematic cross section of WE system showing approximate extent of vapor plume
and vapor extraction well 41
11. Alternative 2 Phase I vapor extraction/monitoring wells 42
TABLES
1. VOC concentrations in monitoring well vapor ports (ECU data) 13
2. Concentrations of validated data for VOCs in perched water 18
3. Mean VOC concentrations in new groundwater monitoring wells 20
4. Constants for evaluating npncarcinogcnic health effects from exposure to COCs 27
5. Constants for evaluating carcinogenic effects associated with exposure to the COCs .... 27
6. Parameters used to model inhalation and ingcstion exposures by current and
future receptors 28
xi
-------
7. Summary of baseline risk assessment results 29
8. Uncertainty factors, OU7-08, INEL 31
9. Summary of ARARs and TBC criteria for OCVZ alternatives 38
10. OCVZ alternative cost estimates (net present value) 49
11. OCVZ selected remedy cost summary 52
xn
-------
ACRONYMS AND ABBREVIATIONS
ARAR Applicable or Relevant and Appropriate Requirement
AT Averaging Time
BW Body Weight
CG4 carbon tetrachloride
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
•
COC Contaminant of Concern
COCA Consent Order and Compliance Agreement
CFM cubic feet per minute
DOE Department of Energy
DOE-ID Department of Energy Idaho Operations Office
ECU Environmental Chemistry Unit
ED Exposure Duration
EF Exposure Frequency
EPA Environmental Protection Agency
FFA/CO Federal Facility Agreement and Consent Order
FR Federal Register
ft feet
HEAST Health Effects Assessment Summary Tables
IDHW Idaho Department of Health and Welfare
in. inch
INEL Idaho National Engineering Laboratory
IR Ingestion Rate
IRIS Integrated Risk Information System
xiii
-------
kg
1
Ibs
m
MCL
mi
min
NCP
NPL
OCVZ
OU
PCE
PRO
PPB
PPMV
RAG
RCRA
RI/FS
ROD
RR
RWMC
SARA
SDA
SRPA
kilogram
liter
pounds
meter
Maximum Contaminant Level
mile
minute
National Oil and Hazardous Substances Pollution Contingency Plan
National Priorities List
Organic Contamination in the Vadose Zone
Operable Unit
tetrachloroethylene
preliminary remediation goal
parts per billion
parts per million volume
Risk Assessment Guidance
Resource Conservation and Recovery Act
Remedial Investigation/Feasibility Study
Record of Decision
Respiration Rate
Radioactive Waste Management Complex
Superfund Amendments and Rcauthorization Act
Subsurface Disposal Area
Snake River Plain Aquifer
xiv
-------
TCA trichloroelhane
TCE trichloroethylcne
TRU Transuranic
TSA Transuranic Storage Area
VOC volatile organic compound
WE Vapor Vacuum Extraction
WAG Waste Area Group
yr year
|tg microgram
XV
-------
XVI
-------
Decision Summary
1. SITE NAME, LOCATION, AND DESCRIPTION
The Idaho National Engineering Laboratory (INEL) is a government facility managed by the
U.S. Department of Energy (DOE) located 32 miles (mi) west of Idaho Falls, Idaho, and occupies
890 mi2 of the northeastern portion of the Eastern Snake River Plain. The Radioactive Waste
Management Complex (RWMC) is located in the southwestern portion of the INEL (Figure 1). The
majority of the organic contamination associated with the Organic Contamination in the Vadose Zone
(OCVZ) operable unit (OU) is within the subsurface of the area outlined in Figure 1, and the highest
contaminant concentrations are found immediately beneath the Subsurface Disposal Area (SDA), an
area with several disposal pits and trenches previously used for the disposal of organic wastes. The
SDA is a 88-acre area located within the RWMC. The RWMC encompasses 144 acres
(approximately 0.23 mi2) and consists of both the SDA and the Transuranic (TRU) Storage Area.
Current land use at the INEL is primarily nuclear research and development and waste
management. Surrounding areas are managed by the Bureau of Land Management for multipurpose
use. The developed area within the INEL is surrounded by a 500 mi2 buffer zone used for cattle a'nd
sheep grazing.
Approximate OCVZ Boundary
s Radioactive Wa*te
Management Complex
Radioactive Waste
Management Complex
Figure 1. The Radioactive Waste Management Complex at the INEL.
1
-------
Of the 11,700 people employed at the INEL, approximately 100 are located at the RWMC. The
nearest off-site populations are in Atomic City (12 mi southeast of RWMC), Arco (16 mi northwest
of RWMC), Howe (19 mi north of RWMC), Mud Lake (36 mi northeast of RWMC), and Terrcton
(37 mi northeast of RWMC).
The INEL property is located on the northeastern edge of the Eastern Snake River Plain, a
volcanic plateau that is primarily composed of volcanic rocks and relatively minor amounts of
sedimentary interbeds. The basalts immediately beneath the RWMC are relatively flat and covered
by 20 to 30 feet (ft) of alluvium.
The depth to the Snake River Plain Aquifer (SRPA) underlying the INEL varies from 200 ft
in the northern portion to 900 ft in the southern portion. The depth to the SRPA at the RWMC
is about 580 ft. Flow of the aquifer in this region is generally to the south-southwest. Organic
contaminants beneath the RWMC are currently migrating toward the aquifer. Some contaminants
have already reached the aquifer, but they are at concentrations that are below Federal and state safe
drinking water standards [i.e.. Maximum Contaminant Levels (MCLs)]. Contaminants that reach the
aquifer are carried by the flow of the groundwater in the southwest direction, potentially beyond the
southern boundary of the INEL.
The INEL has semi-desert characteristics with hot summers and cold winters. Normal annual
precipitation is 9.1 inches per year (iiVvr), with estimated evapotranspiration of 6 to 9 in/yr. The only
surface water present in the southern portion of the INEL is the Big Lost River, which is
approximately 1.5 mi northwest of the RWMC; however, due to irrigation diversions upstream, this
river is typically dry. Surface water is present at the RWMC only during and following periods of
heavy rainfall and snowmelt, which generally occur in January through April.
To minimize the potential for surface water to flow onto the RWMC during periods of high
surface water runoff at the INEL, water is diverted from the RWMC via spreading areas and
associated dikes, located to the west and south of the RWMC. To further enhance surface water
diversion from disposal pits and trenches, berms have also been constructed immediately around the
SDA,
Twenty distinctive vegetative cover types have been identified at the INEL. Big sagebrush is
the dominant species, covering approximately 80 percent of the ground surface. The variety of
habitats on the INEL support numerous species of reptiles, birds, and mammals. Several bird species
at the INEL that warrant special concern because of sensitivity to disturbance or their threatened
status include the ferruginous hawk (Buteo regalis), bald eagle (Haliaeetus leucocephalus). long-billed
curlew (Numenius americanus), and the loggerhead shrike (Lanius Ludovicianus). In addition, the
Townsend's big-eared bat (Plecotus Townsendii) and pygmy rabbit (Brachylagus Idahoensis) are listed
by the U.S. Fish and Wildlife Service as candidate species for consideration as threatened or
endangered species. The ringneck snake, whose occurrence is considered to be INEL-wide. is listed
by the Idaho Department of Fish and Game as a Category C sensitive species.
The OCVZ operable unit is defined as that part of the vadose zone beneath and within the
immediate vicinity of the RWMC where there are organic contaminants in the vapor state. Their
presence is a result of the burial at the SDA disposal pits of organic wastes from the Rocky Flats
Plant in Colorado. OCVZ does not include the wastes remaining in the disposal pits
-------
(i.e., contaminated solids, drums, etc.). It only includes those organic compounds that have migrated
from the wastes. The organic compounds are primarily carbon tctrachloridc, 1,1,1-trichIorocthane,
trichloroethylene, and tctrachloroethylcne.
2. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The RWMC was established in the early 1950s as a disposal site for solid, low level waste
generated by INEL operations. Within the RWMC is the SDA, where hazardous substances,
including radioactive wastes and organic wastes, have been disposed of in underground pits, trenches,
soil vault rows, and Pad A—an aboveground pad. TRU waste was disposed of in the SDA from 1952
to 1970 and was received from the Rocky Flats Plant for disposal in the SDA from 1954 to 1970.
The Rocky Rats PJant is a DOE-owned facility located west of Denver, Colorado. The Rocky Flats
Plant is used primarily for the production of plutonium components for nuclear weapons. Also
located at the RWMC is the Transuranic Storage Area (TSA), where interim storage of TRU waste
occurs in containers on asphalt pads. The TSA accepted TRU waste from off-site generators for
storage from 1970 through 1988. TRU waste generated at the INEL is still stored at the TSA.
Organic contaminants that are part of the OCVZ operable unit are present in the subsurface
fractured basalt'ahd sedimentary interbeds (i.e., the vadose zone) beneath and within the immediate
vicinity of the RWMC, above the SRPA, The presence of organic contaminants in the vadose zone
is a result of the burial, and breach, at the SDA of containerized organic wastes from the Rocky Flats
Plant From 1966 to 1970, approximately 88,400 gallons of organic wastes were mixed with calcium
silicate to reduce free liquids and form a grease- or paste-like material prior to being placed in
containers and sent to the INEL for disposal in several pits at the SDA. Pits 4. 5,6. 9, and 10 have
been identified as receiving the organic wastes. Also, Pit 2 received an unknown quantity of organic
waste before 1966, and the acid pit may have received organic wastes during past operations. The
locations of these pits are shown in Figure 2. Section 11 of this record of decision (ROD) provides
additional information on the waste inventory at the disposal pits of the SDA
A Consent Order and Compliance Agreement (COCA) was entered into between DOE and the
U.S. Environmental Protection Agency (EPA) pursuant to the Resource Conservation and Recovery
Act (RCRA) Section 3008(h) in August 1987. The COCA required DOE to conduct an initial
assessment and screening of all solid waste and/or hazardous waste disposal units at the INEL, and
set up a process for conducting any necessary corrective actions.
On July 14, 1989, the INEL was proposed for listing on the National Priorities List (NPL)
[54 Federal Register (FR) 29820]. The listing was proposed by the EPA under the authorities
granted EPA by the Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA) as amended by the Supcrfund Amendments and Reauthorization Act of 1986 (SARA).
The INEL was listed on the NPL on November 21, 1989 (54 FR 44184).
As a result of the INEL's listing on the NPL in November 1989, DOE, EPA, and the Idaho
Department of Health and Welfare (IDHW) entered into a Federal Facility Agreement and Consent
Order (FFA/CO) on December 9,1991. Under the FFA/CO, OCVZ was identified for a Remedial
Investigation/Feasibility Study (RI/FS). This ROD documents the results of the RI/FS and the
remedy selected. The entire RWMC will be evaluated in the Waste Area Group (WAG) 7
Comprehensive RI/FS which is scheduled to begin no later than July 19%.
-------
Plti Contributing Contaminant*
to VadoM Zone
Subsurface Disposal
ATM
Pad A
SoB Ov«rt»urden
Trmnaunnlc StoraQ*
ATM
= = = Road
' • " Fane*
04 Pit Number
Figure 2. The RWMC with pits contributing organic contamination to the vadose zone.
3. HIGHLIGHTS OF COMMUNITY PARTICIPATION
In accordance with CERCLA § 113(k)(2)(B)(i-v) and 117, a series of opportunities for public
information and participation in the remedial investigation and decision process for OCVZ were
provided over the course of 29 months beginning in November 1991 and continuing through
April 1994. For the public, the activities ranged from receiving a fact sheet that briefly discussed the
OCVZ investigation to date, INEL Reporter articles and updates, and a proposed plan, to having a
telephone briefing, four public scoping meetings, three public meetings, and two open houses to offer
verbal or written comments during two separate 30-day public comment periods.
On November 19,1991, a fact sheet concerning OCVZ was conveyed through a "Dear Citizen"
letter to a mailing list of 5,600 individuals of the general public and 11,700 INEL employees in
advance of the public scoping meetings scheduled on December 9, 10, 11, and 12, 1991. On
November 20, the DOE issued a news release to more than 40 news media contacts concerning the
beginning of a 30-day public scoping comment period, which ended January 3, 1992, on the OCVZ
remedial investigation. Both the letter and release gave notice to the public that OCVZ documents
would be available before the beginning of the comment period in the Administrative Record section
of the INEL Information Repositories located in the INEL Technical Library of Idaho Falls, as well
as in city libraries in Idaho Falls, Pocatello, Twin Falls, Boise, and Moscow. Display ads announcing
the same information appeared in eight major Idaho newspapers. Large ads appeared in the
following newspapers from November 22 to the 27: Post Register (Idaho Falls); Idaho Sate Journal
(Pocatello); South Idaho Press (Burley); Times News (Twin Falls); Idaho Statesman (Boise); Idaho
Press Tribune (Nampa); Lewiston Morning Tribune (Lewiston); and Idahonlan (Moscow).
-------
Similar display ads concerning upcoming meetings appeared in seven of these newspapers several
days preceding each local meeting to encourage citizens to attend and provide verbal or written
comments. All three media—the Dear Citizen letter, news release, and newspaper ads—gave public
notice of four scoping meetings concerning the beginning of the investigation of OCVZ and the
beginning of a 30-day public comment period that was to begin December 4,1991. Additionally, two
radio stations in Idaho Falls and newspapers in'Idaho Falls and other communities repeated
announcements from the news release to the public at large. A total of seven radio advertisements
were made by local stations where meetings were scheduled several days before and the day of the
meetings.
Personal phone calls concerning the availability of OCVZ documents and public meetings were
made to individuals, environmental groups and organizations by IN EL Outreach Office staff in
Pocatelio, Twin Falls, and Boise. The Community Relations Plan Coordinator made calls in Idaho
Falls and Moscow.
Scoping meetings on OCVZ were held December 9, 10, 11, 12, 1991 in Boise, Moscow. Twin
Falls, and Idaho Falls, respectively. An informal open house was held one hour prior to each of the
meetings to allow the public to visit with State and Federal representatives about OCVZ. During
these meetings, representatives from DOE and INEL discussed the project, answered both written
and verbal questions, and received public comments. Written comment forms were distributed at the
meetings. Comments from the scoping meetings were evaluated and considered as part of the RI/FS
process.
Regular reports concerning the status of the OCVZ project were included in the INEL Reporter
and mailed to those who attended the meetings and who were on the mailing list. Reports appeared
in the March, May, July, and November 1992; and the January, March, and July 1993 issues of the
INEL Reporter, During this time the number of individuals on the mailing list increased to 7,000.
Individuals on the mailing list, those who attended the meetings, and all INEL employees received
issues of the INEL Reporter.
Opportunities for public involvement in the decision process for OCVZ were provided beginning
in March 1.994. For the public, the activities ranged from receiving the proposed plan, conducting
one teleconference call, and attending open houses and public meetings to informally discuss issues
and offer verbal and written comments to the agencies during the 30-day public comment period.
On March 18, 1994, the Department of Energy Idaho Operations Office (DOE-ID) issued a
news release to more than 40 news media contacts concerning the beginning of a 30-day public
comment period on the OCVZ proposed plan. The release also gave notice to the public that OCVZ
documents would be available before the beginning of the comment period in the Administrative
Record section of the INEL Information Repositories located in the INEL Technical Library in
Idaho Falls, the Shoshone-Bannock Library at Fort Hall, the University of Idaho Library in Moscow.
the Idaho State Library in Boise; as well as city libraries in Idaho Falls, Pocatelio, Twin Falls. Boise,
and Moscow.
Copies of the proposed plan for OCVZ were mailed to 7,000 members of the public and
400 INEL employees on the INEL Community Relations Plan mailing list on March 28, 1994 urging
citizens to comment on the plan and to attend public meetings. Display ads announcing the same
-------
information and the location of open houses in Pocatcllo and Twin Falls, and public meetings in
Idaho Falls, Boise, and Moscow appeared in seven major Idaho newspapers. Large ads appeared in
the following newspapers from March 15 to 20: Post Register (Idaho Falls), Idaho State Journal
(Pocatcllo), South Idaho Press (Burlcy), Tunes News (Twin Falls), Idaho Statesman (Boise), Lewiston
Morning Tribune (Lewiston), and The Daily News (Moscow).
Similar display ads concerning upcoming meetings appeared in each of these newspapers several
days preceding each local open house or meeting to encourage citizens to attend and provide verbal
or written comments". Both media, the news release and newspaper adds, gave public notice of public
involvement activities and offerings for briefings, and the beginning of a 30-day public comment
period that was to begin March 31 and run through April 30, 1994. Additionally, radio stations in
Idaho Falls, Blackfoot, Pocatcllo, Burley, and Twin Falls ran advertisements during the three days
prior to the open houses in Pocatello and Twin Falls.
The open houses were held in Pocatcllo and Twin Falls on April 12 and April 14, respectively,
and the public meetings were held in Idaho Falls, Boise, and Moscow on April 18, 20, and 21, 1993,
respectively. Written comment forms, including a postage-paid business reply form, were made-
available to those attending the meetings. The forms were used to turn in written comments at the
meeting, and by some, to mail in comments later. The reverse side of the meeting agenda contained
a form for the public to evaluate the effectiveness of the meetings. A court reporter was present at
each meeting to keep a verbatim transcript of discussions and public comments. The meeting
transcripts were placed in the Administrative Record section for OCVZ, OU 7-08. in eight INEL
Information Repositories.
On April 13,1994, a teleconference call between the League of Woman Voters of Moscow and
the Environmental Defense Institute, DOE-ID, EPA, and the IDHW concerning INEL
environmental restoration issues was conducted at the request of Moscow area residents. The call
consisted of an overview of the proposed plan, questions and answers, and general discussion of
OCVZ issues.
Personal phone calls concerning the availability of the proposed plan and the public meetings
were made to individuals, environmental groups, and organizations by INEL Community Relations
Plan staff in Idaho Falls and Boise. Outreach Office staff made calls to citizens in northern,
southwestern, and southeastern Idaho.
Another series of ads were placed in the same local papers several days before the public
meetings to encourage citizens to attend and comment on the plan. Additionally, a special feature
article in the July issue of the INEL Reporter was mailed to individuals on the INEL Community
Relations Plan mailing list as a reminder of the meetings and the opportunity to comment on the
proposed plan.
A Responsiveness Summary has been prepared as part of the ROD. All formal verbal
comments, as given at the public meetings, and all written comments, as submitted, are repeated
verbatim in the Administrative Record for the ROD. Those comments arc annotated to indicate
which response in the Responsiveness Summary addresses each comment.
-------
A total of about 83 people attended the OCVZ public meetings. Overall, 27 provided formal
comments; of these 27 people, 12 people provided oral comments and 15 people provided written
comments. DOE further divided the oral and written comments into 91 separate comments. All
comments received on the proposed plan were considered during the development of this ROD. The
decision for this action is based on the information in the Administrative Record for this OU.
4. SCOPE AND ROLE OF OPERABLE UNIT AND RESPONSE ACTION
Under the FFA/CO, the INEL is divided into 10 WAGs. The WAGs are further divided into
OUs. The RWMC has been designated WAG 7 and consists of 14 OUs. Data from shipping
records, along with process knowledge, written correspondence, and existing monitoring data, were
available to allow OCVZ, OU 7-08, to be evaluated in an expeditious manner. OCVZ consists of
the organic contaminants present in the vadose zone beneath and within the immediate vicinity of
the RWMC, but does not include the waste materials disposed of in the pits of the SDA. Potentially,
organic wastes remaining in the pits could impact alternatives considered for remediation of the
vadose zone. However, given the current level of information available on the organic wastes present
within the pits, it is impossible to predict with any certainty whether these wastes will impact
remediation at all
A complete evaluation of all cumulative risks associated with CERCLA actions at WAG 7 will
be conducted as part of the WAG 7 Comprehensive RI/FS (OU 7-14) to ensure all risks have been
adequately evaluated. Conducting a remedial action at OCVZ is part of the overall WAG strategy
and is expected to be consistent with any planned future actions.
5. SUMMARY OF SITE CHARACTERISTICS
The following sections provide a summary of the physical characteristics of the site as well as
a summary of the contaminants present in various media at the site. Much information on the
characteristics of the vadose zone (including contaminant behavior in the vadose zone) was obtained
during a treatability study using vapor vacuum extraction (WE); therefore, a summary of the
treatability study is included as Section S3.
5.1 Geology and Hydrology
The INEL is located along the northern edge of the Eastern Snake River Plain, a 50- to 70-mi
wide northeastern trending geologic basin extending from the vicinity of Twin Falls on the southwest
part of the plain to the Yellowstone Plateau on the northeast The Eastern Snake River Plain is
underlain by a substantial volume of volcanic rocks with relatively minor amounts of sediment, except
along its margins where drainages emerge from the nearby mountain ranges.
The RWMC is underlain by a thick sequence of basaltic lava flows interbedded with thin layers
of sediments termed "interbcds." A layer of surficial sediments ranging from 0 to 22 ft thick directly
underlies the RWMC. It is within these sediments that the organic wastes were buried at the
RWMC The basalts range from highly fractured and vesicular along the margins of the flows to
more dense and less fractured in the interior portions of the flows. The .interbcds consist of silt, sand,
clay, and fine gravel and arc generally less permeable than the fractured basalt.
7 .
-------
The RWMC is located in the Pioneer Basin, a topographically closed basin which includes most
of the INEL. The Pioneer Basin receives intermittent surface water flow from three drainages that
flow onto the INEL from the northwest: The Big Lost River, Little Lost River, and Birch Creek.
These drainages usually only flow onto the INEL following wet winters. Precipitation at the INEL
averages only 9.1 in (approximately 23 centimeters) per year, but the mountain ranges in the upper
reaches of The Big Lost and Little Lost River Basins to the north and west of INEL receive up to
SO in (approximately 125 centimeters) of precipitation per year. Annual average infiltration rates at
the RWMC are on the order of a few centimeters per year.
During periods of high runoff in the Big Lost River, water is diverted from the river to
spreading basins located to the west of the RWMC. Except for a few hours in the Spring of 1993,
water has not been diverted to the spreading areas since 1985. The SDA has flooded three times
(1962, 1969, and 1982) prior to completion of the extensive dike system surrounding the SDA.
Flooding was a result of local runoff from rain or rapidly melting snow in the spring. Because the
SDA is located in a basin, water entered the SDA on each occasion and flooded some pits and
trenches. Each of these flooding events may have resulted in recharge to perched water zones and
to the SRPA.
The SRPA is present beneath the RWMC at a depth of about 580 ft and, as in the vadosc zone,
consists of a series of basalt flows with interbeddcd sedimentary deposits. The EPA designated the
SRPA a sole source aquifer under the Safe Drinking Water Act on October 7,1991 (194 FR 50634).
The aquifer is relatively permeable due to the presence of fractures, fissures, and voids such as lava
tubes within the basalt Groundwater flow in the SRPA is to the south-southwest at rates on the
order of 5 to 20 ft/day. Infiltration of surface water from the spreading basins to the aquifer has in
the past temporarily changed the local gradient beneath the SRPA to the east.
Perched water has been detected in 7 of 45 groundwater monitoring wells drilled at the RWMC.
Perched water occurs where infiltrating water accumulates above relatively less permeable zones in
the subsurface such as the sedimentary interbeds. Limited zones of perched water have been
identified above interbeds located at both 110 and 240 ft The perched water bodies appear to be
laterally discontinuous and are generally only a few feet thick. As such, they are not a viable source
of water in the site area.
5.2 Nature and Extent of Contamination
The presence of organic contaminants in the vadose zone is a result of the burial, and presumed
breach, at the SDA of containerized organic wastes from the Rocky Flats Plant in Colorado.
According to Kudera (Estimate of Rocky Flats Plant Organic Wastes Shipped to the RWMC, internal
note, EG&G Idaho, Inc., July 24, 1987), from 1966 to 1970, approximately 88,400 gallons of
containerized organic wastes were disposed of in the SDA. The organic wastes were mixed with
calcium silicate to reduce free liquids and form a grease- or paste-like material which was usually
double-bagged and placed in drums prior to disposal in several pits at the SDA. In addition, small
amounts of absorbent, such as Oil-Dri, were normally mixed with the waste to bind free liquids. The
organic wastes consisted of lathe coolant (Texaco Regal Oil and carbon tetrachloride), used oils, and
degreasing agents (i.e., chlorinated hydrocarbons) such as 1,1,1-trichloroethane, tricholoethylcne. and
tetrachloroethylene. Hereinafter, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, and
8
-------
tetrachloroethylene will be referred to using their common abbreviations of CC14, 1,1,1-TCA. TCE,
and PCE, respectively. Specific components of the organic wastes were estimated by Kudcra to
include 24.000 gallons of CC14 and 25,000 gallons of other chlorinated hydrocarbons. The balance
of the 88,400 gallons was primarily Texaco Regal Oil. Pits 2, 4, 5, 6, 9, and 10 have been identified
as receiving the organic wastes, and the acid pit may have received organic wastes. These pits, shown
in Figure 2, are suspected of being the source of organic contamination in the vadose zone.
Section 11 of this record of decision (ROD) provides additional information on the waste inventory
at the disposal pits of the SDA.
CC14,1,1,1-TCA, and PCE are considered spent solvents, meeting the definition under IDAPA
§ 16.01.050.05 (40 CFR 261J1). However, the spent solvents were disposed of in the pits at INEL
. prior to the promulgation of the RCRA regulations in 1980. The RCRA regulations are relevant and
appropriate to these spent solvent wastes according to the criteria of the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP) regulations.
Sampling conducted for the remedial investigation (RI) has documented that volatile organic
compounds (VOCs) have migrated from the disposal pits into the vadose zone. In the vadose zone,
VOCs are migrating both vertically (primarily downward) and laterally away from the disposal pits.
Vertical migration of contaminants occurs both by vapor diffusion and infiltration of moisture through
the vadose zone. Lateral migration occurs primarily by diffusion of VOC vapors. VOCs have been
detected in soil vapor, surficial soils, perched water, and in the SRPA. The occurrence of VOCs in
each of these media is discussed in the following paragraphs.
Shallow Soil Vapor
VOC concentrations in shallow soil vapor were evaluated through soil-gas surveys and gas
chromatography conducted in 1987 and 1992. Soil vapor samples were collected through a vapor
probe driven 30 in into surficial soil. In general, both surveys yielded the highest VOC concentrations
in the vicinity of the pits known to contain organic waste. Of the VOCs analyzed, CC14
concentrations were highest in both surveys. The results of the 1992 shallow soil-gas survey are
plotted for CC14 on Figure 3. Elevated concentrations of CC14 were detected above several of the
pits including Pits 2,4,6, 9, and 10. These results document that VOCs have migrated in the vapor
phase from the source pits into shallow soils at the SDA.
The rate at which VOC vapors are being emitted from the shallow soils to the atmosphere was
measured using a surface flux chamber at 12 locations at the SDA. Detectable concentrations of one
or more VOCs were measured by gas chromatography at 11 of the 12 flux chamber test locations.
CC14 was the target compound measured most frequently and at the highest concentrations. The
highest calculated emission rate, 38 micrograms per square meter per minute (ug/m2/min), occurred
at a location near Pit 6. TCE and chloroform were the compounds with the next highest emission
rates (up to 6.6 and 4.3 ug/m2/min, respectively). Although there are no records indicating
chloroform was one of the organic wastes placed in the disposal pits, its presence was confirmed
during field investigations. Clarification on the presence of chloroform can be found in this ROD
in Section 6.1.1, Identification of Contaminants of Concern. Acetone and PCE had calculated
emission rates up to 3.7 and 3.1 ug/m2/min, respectively, while none of the other compounds had
emission rates above 2 ug/m2/min.
-------
SDA BOUNDARY
N
W K
ABOVE 200 ppm
100-200 ppm
75-100 ppm
50-75 ppm
20-50 ppm
5-20 ppm
1-5 ppm
BELOW 1 ppm
EXPLANATION
.63 • Highest Measured Concentration ol
Carbon Tetrachloride in Area
250 125 0
250 500
SCALE IN FEET
Figure 3. CCI4 concentrations in shallow soil vapor at the SDA (1992).
-------
Shallow Soils
Shallow borings drilled in 1990 around the perimeter of Pit 9 and the Acid Pit were sampled
from depths ranging from 0-2 ft to 23 ft. Over 40 samples were analyzed for VOCs. Sampling results
indicated that with a few exceptions, all of the positively identified VOC concentrations were at
depths of 8 to 23 ft, indicating that VOCs are generally present in the lower portions of the surficial
sediments. None of the VOC concentrations exceeded 40 micrograms/kilogram (ug/kg) and all
reported concentrations were well below risk-based screening levels.
Vadose Zone Vapor
A total of 19 vapor port monitoring wells were used to evaluate the extent and concentration
of VOC vapors in the vadose zone. These wells are shown on Figure 4. Samples were collected
between July 1992 and March 1993 and analyzed at the Site by a portable Scntcx Scentograph Gas
Chromatograph Unit. The Sentex was calibrated to detect three VOCs: CC14, TCE, and chloroform.
Approximately 10% of the samples collected between July and September 1992 were submitted to
the Environmental Chemistry Unit (ECU) laboratory at the Central Facilities Area for analysis of a
more complete suite of organic compounds using a modified EPA TO-14 method. These results are
summarized in Table 1.
The ECU data provide a means of comparing CC14 concentrations with concentrations of less
prevalent VOCs. CC14 concentrations are generally one order of magnitude higher than TCE,
chloroform, and 1,1,1-TCA concentrations. Concentrations of PCE, toluene, 1,1.2-trichloro-
1^2-triflouroethane, and acetone are generally two orders of magnitude less than CC14
concentrations. These data indicate that CC14 is the VOC with the highest concentrations in vadose
zone vapor. CC14 concentrations are highest in vapor port monitoring wells located inside the SDA
(8801, 8902, and D02), which are located in the central portion of the SDA around Pits 4, 5, 6,
and 10.
Mean CC14 data from 1992 samples are plotted on cross section A-A* (Figure 5). Cross section
A-A' is identified on Figure 4. The cross section illustrates that concentrations decrease laterally
from the area beneath the source pits and decrease substantially with depth below the 240-foot
interbed. The 240-foot intcrbed appears to provide a layer which impedes or delays downward vapor
migration, based on VOC concentration in the deeper vapor port monitoring wells located outside
the SDA. The 110-foot intcrbed also appears to provide a barrier, especially in the central portion
of the SDA such as at Well 8801. In this area where higher VOC concentrations are present,
concentrations decrease significantly below the 110-foot interbed. No vapor ports have been
completed below the 240-foot interbed within the SDA so it is not possible to evaluate the VOC
concentrations below the 240-foot interbed directly beneath the source pits. •
Data from the new vapor port monitoring wells indicate that CC14 has migrated in the vapor
phase laterally as far as 3,000 ft beyond the SDA boundary. However. CCI4 concentrations in wells
located greater than 500 to 1,000 ft from the SDA boundary are three to four orders of magnitude
less than concentrations in the immediate source areas.
11
-------
A
*» WWWI
• tin* ol CroM-S«cUon A A
(Flgura t)
TSA
MlWVtt
MiowvE 10
OU&GS III
OM40/WE4
EX PI AN AI ION
O Vipot/Ground Waltf Uamnng Wei Pw*
WE • V*p
-------
Table 1. VOC concentrations in monitoring well vapor ports (ECU data).
WE-1
Compound I Port*
Depth (ft)*
Cd4
Qjloroform
PCE
Toluene
1,1,1-TCA
TCE
1,1,2-lrkhloro-
1,2,2-lrifluoro-
ethane
Acetone
Compound I Port»
Depth (ft>»
CC1<
Chloroform
PCE
Toluene
1,1,1-TCA
TCE
1,1,2-trichloro-
PI
189
23
1.4
0.67 J
0.17J
1.8
3.8
0.73
0.82
PI
566
0.36 J
.064 J
.OI8J
.023J
.029 J
0.14 J
<.OI4
P2
127
32
2.1
1.0
-------
Table 1. (continued).
WWWI
Compoundl Port-
Depth (ft>
CO,
Chloroform
PCE
Toluene
1,1,1-TCA
TCE
1.1,2-trichloro-
1 ,2,2-trinuorocthanc
Acetone
PI
240
63
0.93 J
0.16J
<.058
036 J
1.6
0.24 J
0.64 J
P3
135
18
13
0.65 J
<0.25
1.4
4.0
0.56 J
<0.80
8801
F4
78
3000
640
<29
<27
110
480.
<28
<83
8902
P6
71
1200
190
18
<11
54
190
14
<36
P6
71
2500
470
<22
<20
88
360
21
-------
5100
SOOO
t
f
z
4800
4700
4000
two
4400
4100
4*00
4400
4700
4 tOO
EXPLANATION
I.WW O.J
CCMtiilHAliOtiiiuw^ GW:<1 I
jvfuwH (t«JN VIA I'*i I
Figure 5. 1992 mean carbon leuachlonde
concentrations observed in vapor port
monitoring wells along cross-section A-A
Figure 5. Mean CCI4 subsurface vapor concentrations along cross-section A-A1.
-------
Perched Water
Prior to 1992, perched water had been detected in seven wells or boreholes (Figure 6). Wells
known to contain perched water were sampled in 1992. Only three wells, 77-2, USGS 92, and DlO,
yielded enough water for samples. Results of analyses on these samples for VOCs are summarized
in Table 2. The highest VOC concentrations in perched water samples were* detected in Well
USGS 92. CC14, TCE, chloroform, and PCE were the VOCs with the highest concentrations within
this well The concentrations of these VOCs in Wells 8802D and DlO were an order of magnitude
less than the concentrations found in USGS 92. The CCI4 and TCE concentrations in all of the
perched water samples exceed their respective MCLs; however, perched water is not used for any
purpose in the RWMC area and is too limited in both vertical and lateral extent to provide a
dependable source of water.
Groundwater
The results of sampling and analysis of groundwatcr in the SRPA from both USGS and new
"M" series wells are illustrated on Figure 7. While no significant VOC contamination was present in
monitoring wells upgradient of the SDA, VOCs were detected in all eight USGS wells and all six new
"M" series monitoring wells located in the immediate vicinity of the SDA.
The most widely detected VOCs in USGS wells near the SDA were CC14 and TCE. The
compounds detected in decreasing order of maximum historically detected concentrations are: CC14
[6.6 micrograms per liter (ug/1)], dichlorodifluoromethane (2.4 ug/1), TCE (1.4 ug/1), toluene (1.2 ug/1),
chloroform (1.0 ug/1), and 1,1,1-TCA (0.9 |ig/l). Only the CC14 concentration of 6.6 ug/1 in Well
USGS 88 was above its MCL of 5 ug/L This sample was collected in 1987; all subsequent samples
from this well have contained less than 5 ug/1. All other results for VOCs from samples collected in
USGS wells have been below MCLs.
New monitoring Wells MIS, M3S, M4D, M6S, M7S, and M10S (Figure 7) were sampled and
analyzed for VOCs three times between October 1992 and May 1993. Mean VOC concentrations
in these new wells are listed in Table 3. Toluene had the highest mean concentrations of any of the
VOCs in the new wells. Mean toluene concentrations ranged from not detected in Wells M3S and
M6S to 1.0 ug/1 in Wells MIS and M7S, 5.4 ug/1 in Well Ml OS and 10.8 ug/1 in Well M4D. CC14
concentrations of 1.7 and 33 ug/1 were detected in Weils M6S and M7S, respectively. TCE was
detected at a mean concentration of 2.0 ug/I in Well M7S. Methylene chloride was detected at a
concentration of 23 ug/1 in Well MIS. None of the detected concentrations in the new groundwater
monitoring wells exceeded MCLs.
5.3 Results of WE Treatability Studies
To provide information on the viability of vapor vacuum extraction (WE) as a remedial process
for the OCVZ, a treatability study was conducted at the SDA in 1993. The treatability study used
a pilot-scale WE system consisting of a vapor extraction well (8901D), a vacuum pump, and a vapor
treatment system. Two carbon bed adsorbers placed in series were used to remove the VOCs from
the extracted air. In addition to providing performance information on WE, the treatability study
yielded information on the characteristics of the vadose zone. This information is noted below.
16
-------
USGS-96
(209)
(4803)
USGS-92or
(212)
(4795) v
SUBSURFACE
DISPOSAL
AREA
N
\v
EXPLANATION
(DEPTH BELOW LAND SURFACE)
(WATER LEVEL ELEVATION)
o PERCHED WATER WELL
180-230 FT. BLS
Cl PERCHED WATER WELL
80-100 FT. BLS
Figure 6. Location of wells that have contained perched water at the SDA.
-------
Table 2. Concentrations of validated data for VOCs in perched water (jig/1 or ppb).
Parameter
Methylene chloride
1,1-dichloroe thane
Chloroform (100)*
1,1,1-TCA (200)a
CQ4 (5)*
1,1-dichloropropane
TCE(5)a
1,2-dichloropropane
Bromodichloromethane
Toluene (1000)1
PCE (5)"
Dibromochloromethane
Ethylbenzene
p&m-Xylene
Styrene
1.2,4-trimeihyIbenzene
1^,4- trichlorobenzcnc
HoQchlorobutadiene
Napthalene
1,23-trichlorobcnzcne
a. EPA Primary Drinking Water
USCS 92 8802D
<100 <10
<100 <10
UOO ND
<100 15
2100 190
<100 <10
1600 150
<100 <10
<100 <10
<100 3J
230 13
<100 <10
<100 <10
<100 <10
9J <10
<100 <10
<100 <10
ND <10
<100 <10
<100 <10
Standard 40 CR 141.61. jig/1 or
Wells
D10b
ND
<1
ND
3
18
<1
13
1
<1
0.6J
4
<1
0.5J
2
<1
0.2J
ND
<1
ND
-------
ICAROON icnucinomoc .0110
ll I I IHlCHIONOtlHANE.OiOI
|OCI« OBOOIHOUHOUE IHANt .0 i 0 1
GUIS
|CAAOO>l HI«»Cmufi U )T|
IflCKGflClTmlC'.f 10
ItOutlii Itf J
.o;*OOOfOOU JIJOJ
EXPVANATlON
o uSGS Ground Water MonKMng Wei
Showing Range ol VOC Concanuaboni in utyi
o GiounO Water Monncxing We I
Shooing Uetn VOC Concentration in ug/l
Noia Mean VOC concenuations calculaud
bom Uvee quarter! ol ground-walai
monnoingdaia Only tfx>M meani Inal
are above the detection Umit are. shown.
CARBON IClRACwOniOE 06 I 1
1.11 TRio*.onociHMCl«O«OOlflUOOOUtIrt»N£ .01 2 0
taut HE .0; 01
CROUNOWAIEH
HOW DlHlCtKX
OUoi
Figure 7. Summary of groundwatcr analyses for samples taken from the SRPA near SDA.
-------
Table 3. Mean VOC concentrations in new groundwater monitoring wells (ug/1 or ppb).
Wells
VOCs
Methylene chloride
Chloroform
1.U-TCA
Cd«
TCE
Bromo-dichloromethane
Toluene
PCE
1.2-dichloroethane
Detection
MCL limit
—
100
200
5
5
100
1.000
5
—
I
1
1
1
1
1
1
1
1
MIS
23
ND
ND
ND
ND
ND
1.0
ND
-ND
M3S
ND
ND
ND
ND
ND
ND
ND
ND
ND
M4D
ND
ND
ND
ND
ND
ND
10.8
ND
ND
M6S
ND
ND
ND
1.7
ND
ND
ND
ND
ND
M7S
ND
ND
ND
33
2.0
ND
1.0
ND
ND
M10S
ND
ND
ND
ND
ND
" ND
5.4
ND
ND
Note: Mean concentrations calculated by taking the mean of the mean concentrations for each of the three
quarters of monitoring data. Mean concentrations below the detection limit of 1 «g/l reported as not detected.
ND » Not Detected.
Several tests were conducted during the 1993 treatability study to optimize WE performance
and to evaluate hydraulic characteristics of the vadose zone. During extraction well testing, a straddle
packer was used to isolate various intervals to define zones of high permeability that could sustain
high flowrates. These tests showed that a zone adjacent to the 110-ft interbed had the highest
calculated permeability (15 darcies) and, therefore, the highest sustainable pumping rate. Extraction
rate tests, in conjunction with vertical permeability study results, indicate that horizontal permeability
varies considerably, ranging from less than 0.01 to 15 darcies, while vertical permeability ranges from
0.5 to 4 darcies.
When the treatability study began in April 1993. the total VOC concentration was approximately
1,000 parts per million volume (ppmv) in the extraction stream at a flowrate of about 170 cubic feet
per minute (cfm). By June 3,1993, the total VOC concentration dropped to 300 to 500 ppmv at the
same flowrate. From June 3 to July 20, the system was not operated due to the need to replace
spent carbon beds. After carbon bed replacement, the system was restarted on July 21 and the total
VOC concentration had rebounded to approximately 600 ppmv in the extraction stream. The total
VOC concentration stabilized and remained between 400 and 500 ppmv for the remainder of the
treatability study. The 1993 treatability study operation recovered approximately 1,340 kg (2,900 Ibs)
of VOCs.
20
-------
Long-term WE testing showed that continued operation of the WE system influenced VOC
concentrations in vapor monitoring wells as far away as 450 ft from the extraction well.
Concentrations in nearby vapor monitoring wells showed the greatest decreases in the 110-ft interbcd
but also decreased above and below the 110-ft interbcd.
VOCs extracted during the treatability study were captured effectively from extracted vapor
using carbon adsorption beds. These beds were shipped to an approved facility in Texas for final
disposal at the completion of the treatability study.
6. SUMMARY OF SITE RISKS
The human health risk assessment for OCVZ evaluated both present and future potential
exposures to contaminants. The risk assessments were conducted in accordance with the EPA Risk
Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual and Volume II:
Environmental Assessment Manual and other EPA guidance. The risk assessment methods and results
are summarized in the following sections.
6.1 Human Health Risks
The risk assessment consisted of contaminant identification, exposure assessment, toxicity
assessment, and human health risk characterization. The organic contaminants identified for OCVZ
were based on existing inventory records and site characterization data. The exposure assessment
detailed the exposure pathways that exist at the site for workers, off-site residents and potential
future on-site residents. The toxicity assessment documented the adverse effects that may be caused
in an individual as a result of exposure to a contaminant associated with OCVZ.
The human health risk assessment evaluated current and future potential noncarcinogenic health
effects and carcinogenic risks associated with exposure to organic contaminants identified in the waste
inventory. The human health evaluation used both the exposure concentrations and the toxicity data
to determine a hazard index for potential noncarcinogenic effects and an excess cancer risk level for
potential carcinogenic contaminants. In general, when a hazard index exceeds one, there may be a
concern for potential noncarcinogenic health effects. The excess cancer risk level is the increase in
the probability of contracting cancer. The NCP acceptable risk range is 1 in 10,000 to 1 in 1.000,000
(Le., 1 x 10"* to 1 x 10"6). An excess lifetime cancer risk of 1 in 10,000 indicates that an individual
has up to one chance in ten thousand of developing cancer over a lifetime of exposure to a site-
related contaminant.
6.1.1 Identification of Contaminants of Concern
Organic contaminants of concern (COCs) evaluated in the baseline risk assessment were
selected based on historical waste records and on the nature and extent of these contaminants in
vadose zone media. The COCs selected for OCVZ are CCI4, PCE, TCE, and 1,1.1-TCA. These
compounds have been identified as known waste constituents.
Chloroform was not identified in the waste history for the SDA; however, it was detected in site
monitoring samples. Investigations pertaining to this contaminant indicate that the chloroform may
21
-------
have two sources, both of which arc difficult to quantify. Dose reconstruction activities for the Rocky
Flats Plant in Colorado have identified chloroform usage associated with weapons component
production; however, the presence of chloroform in the INEL waste is not documented. Chloroform
may also have resulted from anaerobic degradation of CC14, a known contaminant at the SDA.
Therefore, chloroform may have either been initially present in the waste as a source term (but not
reported), or it may have been produced by degradation of CC14. Since estimates from these
potential sources have not been quantified, it is impossible to quantitatively evaluate the risk to
human receptors from the migration of chloroform. Similarly, no data are available which document
the presence of acetone or toluene in the waste. As such, chloroform, acetone, and toluene were
not identified as COCs. The uncertainty associated with not including these contaminants in the risk
assessment is discussed in Section 6.1.5.
6.1.2 Exposure Assessment
An exposure assessment was performed to estimate the magnitude, frequency, duration, and
routes of human exposure to the organic contaminants present in the vadosc zone.
Exposed Populations
Only exposure pathways deemed to be complete (i.e., where a plausible route of exposure can
be demonstrated from the site to an individual) were quantitatively evaluated in the risk assessment.
The populations at risk due to exposure to organic COCs present in the vadose zone were identified
by considering both current and future land use scenarios.
The human health risk assessment evaluated carcinogenic risks and noncarcinogenic health
effects for the period from 1992 through 2121. This window of time for evaluating risks was selected
because it is during this time that peak contaminant concentrations occur in the SRPA. The period
was further divided into three current and future use time periods:
1. Current period (1992-2021). Control of the RWMC will be maintained by the DOE
during this period of time. Potential exposures to on-site workers or visitors and residents
adjacent to the INEL were evaluated. Institutional control of the RWMC is defined in
an Institutional Control Plan for the INEL per DOE Order 5820.2a.
2. Institutional control period (2022-2091). Control of the RWMC will be maintained by the
DOE during this period of time. Institutional controls would be implemented to control
the facility and may include, but arc not limited to, restricting land use. controlling public
access, and the posting of signs, fencing, or other barriers. Potential exposures to on-site
workers or visitors and residents adjacent to the INEL were evaluated.
3. Post-institutional control period (2092-2121). Only potential exposures on residents were
evaluated for this time period. Hypothetical residents were evaluated at 200 meters (which
is approximately the distance from the center of the SDA to its boundary), 500 meters, and
5,200 meters from the center of the SDA. Each of these three locations is southwest of
the SDA—the normal direction of flow for the SRPA. Note that the 5.200 meter location
is the southern INEL boundary.
22
-------
Exposure Pathways
The following exposure pathways were evaluated in the risk assessment for the current,
institutional, and post-institutional control periods. In order to complete the pathways evaluation,
contaminant fate and transport modeling was performed. The use of modeling is discussed in the
following section.
• Outdoor inhalation of organic vapors
• Indoor inhalation of organic vapors
• Indoor inhalation of organic vapors released from indoor use of groundwater
• Dermal contact with groundwater
• Ingestion of groundwater (by hypothetical residents only).
Ingestion of contaminated groundwater by workers during the current and institutional control
periods was not considered a viable pathway because the water supplied to workers from the RWMC
production well is tested for contaminants. If contaminants in this well were to exceed MCLs, the
water would be treated, or water from an uncontaminated source would be supplied to the workers.
The estimated risks and potential health effects associated with the pathway of dermal contact
with groundwater turned out to be very low relative to the pathways of inhalation and ingestion. As
such, for purposes of summarizing risk in this ROD, following discussions focus on inhalation and
ingestion. Details for all of the pathways considered can be found in Sections 5 and 6 of Remedial
Investigation/Feasibility Study Report for the Organic Contamination in the Vadose Zone—Operable
Unit 7-08 (EGG-ER-10684).
Contaminant Fate and Transport Modeling
A two-dimensional numerical transport model was developed to characterize the migration of
contaminants from the disposal pits, through the vadose zone to the SRPA and to the atmosphere.
Two additional models used the results of the vadose zone modeling to subsequently simulate the
transport of contaminants in the SRPA and in the atmosphere. Also, the vadose zone model results
were used to calculate COC concentrations in hypothetical building basements.
The computer code PORFLOW Version 239 was used to simulate transport of contaminants
in the vadose zone. The source term of the model was based on Kudera's estimates which are
described in Section 5.2. The model was calibrated using 1992 vapor concentration measurements
of CC14 from wells instrumented with vapor sampling ports. The model was then used to predict the
mass flux of each COC to the atmosphere and the SRPA from 1966 to the year 2193. The material
properties used in the model are based on data collected during the RI, historical data, and
calibration of the model.
The vadose zone model results provide mass fluxes to the air and groundwater pathways as a
function of time and provide the basis for COC concentrations at receptor locations. As expected.
23
-------
the CC14 flux is higher than the other COCs. The peak flux to the atmosphere for each COC occurs
shortly after disposal ceased in 1970. CC14 flux to groundwatcr is predicted to peak in 2071, with flux
to groundwatcr of the other COCs peaking in 2074.
A two dimensional transient analytical model, AT123D, was used to simulate the migration of
COCs in the SRPA from beneath the SDA and predict concentrations of the four COCs through
time (1966 through 2193) at three receptor locations downgradient ISCLT Version 2.0 was used to
model airborne contaminant transport to predict maximum average concentrations of COCs in air at
specified receptor locations. The predicted groundwater and air concentrations were then used in
the baseline risk assessment.
Results of the vadose zone model were also used to estimate COC vapor concentrations in
hypothetical building basements at the 200 and 500 meter receptor locations for use in the baseline
risk assessment Estimates of building concentrations were made with a simple mixing equation for
each exposure period. This equation assumes instantaneous mixing and steady state conditions for
each time period. The results of this model are building concentrations for 1966 through 2193 for
each COC for the 200 and 500 meter receptor locations. These concentrations were then used in
the baseline risk assessment
Exposure Point Concentrations
COC concentrations at points where the potential for human exposure is expected to occur are
necessary to evaluate the intake of potentially exposed individuals. The contaminant fate and
transport models described above provided COC concentrations in both air and groundwater at
selected exposure point locations.
COC transport modeling indicated that the flux of COCs from the vadose zone to the
atmosphere and the resultant airborne COC concentrations have peaked and will continue to
decrease through the current, institutional, and post-institutional control periods. As such, exposure
to airborne COCs will be greatest during the current control period. Figure 8 shows total COC
emission to the atmosphere over time. The emission of COCs to the atmosphere results in an
airborne COC concentration during the current period that ranges from approximately 15 ug/m3 at
the WAG 7 boundary (200 m from center of SDA) to 0.00637 ug/m3 at the southern INEL boundary
(5,200 m from center of SDA).
Unlike the airborne COC concentrations, the COC concentrations in groundwater will not peak
until around the year 2071, which is during the latter part of the institutional control period. As
shown in Figure 9, each COC peaks at a different concentration, with CC14 peaking the highest at
approximately 125 ug/1 or ppb. Three of the COCs, CC14, TCE, and PCE are predicted to remain
above MCLs beginning early in the current period and extending beyond the institutional control
period. The concentrations shown on Figure 9 are predicted for groundwater at the SDA boundary.
Detailed discussions on exposure point concentrations can be found in Volume I, Section 5 of
the Remedial Investigation/Feasibility Study Report for the Organic Contamination in the Vadose
Zone-Operable Unit 7-08 (EGG-ER-10684).
24
-------
80
«• w
l!
10
0
1995
2000
2005
Year
2010
2015
2020
—_— Carbon T«wchlo»W« (CO)
--•-. Trichlorottftylenc (TCE)
T0trachloroeftyt«ne (PCE) and
1,1,1-TrtcttcroethanefrCA)
Figure 8. Total COC emission to the atmosphere over time.
140
130
120
110
3 ioo
£ 00
60
8 70
60
50
40
30
20
10
0
1875 2000 2025 2050 2075 2100 2125 2150 2175 2200
YMT
. Cartoon Tctrachlorid* (CO)
• - - - - Trtehloro«tttyton« (TCE)
T«tr»cWoro«thyl»n» (PCE)
— — - 1.1.1-Tf1chloroethan»(TCA)
Figure 9. COC concentrations in the SRPA at the SDA boundary over time.
25
-------
6.1.3 ToxicHy Assessment
The toxicity assessment addresses the potential for a contaminant to cause adverse effects in
exposed populations and estimates the relationship between extent of exposure and extent of toxic
injury (Le., dose response relationship).
Two types of toxicity values were used in the risk assessment: chronic reference doses, which
are used to evaluate noncarcinogenic effects; and slope factors, which are -used to evaluate
carcinogenic effects. The Integrated Risk Information System (IRIS) database, an EPA online
computer database, and the EPA Health Effects Assessment Summary Tables (HEAST) provided
toxicity values and slope factors for the COCs present at OCVZ. These reference doses and slope
factors are listed in Tables 4 and 5, respectively. Reference doses and slope factors are "pathway
specific;" that is, they are dependent on the means of contaminant exposure.
The COCs, except for 1,1,1-TCA, arc known carcinogens that target the liver and lungs. The
potential carcinogenic effects of 1,1,1-TCA cannot be evaluated due to insufficient data on the
carcinogenic effects of this compound. Each of the contaminants has harmful noncarcinogenic effects
(both acute and chronic) on the central nervous system, liver, and lungs.
6.1.4 Risk Characterization
Risk characterization is the process of combining the results of the exposure and toxicity
sments. This process provides numerical quantification relative to the existence and magnitude
of potential public health concerns related to the potential release of contaminants from the site.
Exposure parameters, such as exposure frequency and duration, used in the risk assessment were
obtained from Standard Default Exposure Factors guidance (EPA Risk Assessment Guidance for
Superfund, Volume I:. Human Health Evaluation Manual, Supplemental Guidance, Standard Default
Exposure Factors, OSWER Directive 9285.6-03,1991). The exposure parameters used are shown in
Table 6. As noted earlier, the summary format of this ROD focuses on inhalation and ingestion
because, relative to these pathways, dermal absorption contributed very little health risks or effects.
Risk calculations are divided into carcinogenic and noncarcinogenic categories. The calculation
of health risks from potential exposure to carcinogenic compounds involves the multiplication of
cancer slope factors for each carcinogen and the estimated intake values for that contaminant.
Noncarcinogenic health effects are assessed by comparison of an estimated daily intake of a
contaminant to its applicable reference dose. A reference dose is a provisional estimate of the daily
exposure to the human population that is likely to be without an appreciable risk of deleterious
effects during a portion of an individuals lifetime. The estimated daily intake of each contaminant
by an individual route of exposure is divided by its reference dose and the resulting quotients are
added to provide a hazard index.
Carcinogenic risk and noncarcinogenic health effects associated with OCVZ are summarized in
Table 7. As shown in this table, carcinogenic risks arc estimated to be below or within the acceptable
risk range of 1 x 10^* to 1 x 10"* for all receptors under the current period and for the worker
receptors under the institutional control period. An estimated two additional residential receptors
out of 10,000 (2 x 10"4) arc at risk of developing cancer as a result of the use of contaminated
26
-------
Table 4. Constants for evaluating noncarcinogenic health effects from exposure to COCs.
Chronic reference doses •
Chemical
CC14
PCE
TCE
1,1.1-TCA*
Oral
(ing/kg/day)
7x ID"4*
lx 10'2d
NA
9 x 10'2 h
Inhalation
(mg/kg/day)
1.8 x 10'3 b
lxlO'2c
NA
3xurl
(Bg/m3)
6.1b
35e
NA
lx 10°
Subchronic
RfD
(mg/kg/day)
7 x 10'3 c
IxlCT"
NA
9 x 10'1
Total organ
Liver
Liver
Lung/Liver
Liver
a. IRIS (2/93). Last update 10/7/92.
b. Calculated from oral RfD assuming inhalation: oral absorption ratio of 0.4 (see carcinogenicity data table).
c. HEAST (1992) -«*
d. IRIS (2/93). Last update 4/6/92.
c. Calculated from oral RfD assuming an inhalation volume of 20 m3/day for a 70-kg adult. No correction
for relative absorption efficiency.
f. HEAST(1991).
g. Information from HEAST (1991). Last IRIS update 10/7/92.
h. Notes in HEAST (1991) indicate that this value is based on extrapolation from inhalation data. The
assumed relative absorption efficiency (inhalation: oral) appears to be 03.
Table 5. Constants for evaluating carcinogenic effects associated with exposure to the COCs.
Slope factors
Chemical
c
-------
Table 6. Parameters used to model inhalation and ingcstion exposures by current and future
receptors.
Parameter
Inhalation
Respiration Rate (RR)
Exposure Frequency (EF)
Exposure Duration (ED)
Body Weight (RW)
Averaging Tune (AT)
Imestion
Ingcstion Rate (IR)
Exposure Frequency (EF)
Exposure Duration (ED)
Body Weight (BW)
Average Time (AT)
a. Risk Assessment Guidance
b. Statement of Work RI/FS
Receptor group
Adult/child
Adult/child
Worker
Adult
Child
Worker
Adult/worker
Child
Adult
Child
Worker
Adult/Worker
Adult
infant (0-3 yean)
child (3-6 years)
Adult/child
Adult
Child
Adult
Child
Adult
Child
Adult
for Supcrfund (RAGS), U.S. EPA,
Risk Assessment Dcliverables, EPA
RME value
20 m3/day (total)
IS irP/day (indoor)
350 days/year
250 days/year
24 years
6 years
25 years
70 kilogram (kg)
15kg
8,760 days {noncarcinogens)
2,190 days (noncarcinogens)
9125 days (noncarcinogens)
25450 days (carcinogens)
2.0 I/day
0.53 I/day
0.74 I/day
350daysfycar
24 years
6 years
70kg
15kg
8,760 days (noncarcinogens)
2,190 days (noncarcinogens)
25^50 days (carcinogens)
1991.
Region 10, U.S. EPA, 1990.
Reference
EPA RAGS3
EPA RAGS
EPA RAGS
EPA RAGS -
EPA RAGS
EPA RAGS
EPAb
EPAb
EPA RAGS
EPA RAGS
EPA RAGS
EPA RAGS
28
-------
Table 7. Summary of baseline risk assessment results.
Receptor' Exposure timcframc Carcinogenic riskb
Nonoircinogcnic risk Primary contributing
(hazard index )c exposure route
Current Scenario (1992 to 2021)
Worker— 200 meters
Worker— 500 meters
Resident adult— 5,200 meters
Resident child-5,200
1992-2016
1992-2016
1992-2021
1992-2021
6 in 100,000 (6 x JO'5)
4 in 1,000,000 (4 x 10*)
1 in 100,000 (lx 10's)
_d
2
0.1
0.3
0.3
Air
Air
Groundwater
Groundwater
Institutional Control Scenario (2022 to 2091)
Worker-200 meters6
Worker— 500 meters*
Resident adult— 5,200 meters
Resident child— 5,200 meters
2062-2086
2062-2086
2062-2091
2062-2091
9 in 10,000,000 (9 x 10'7)
2 in 1,000,000 (2 x. 10*)
2 in 10,000 (2 x 10"4)
_d
0.03
0.07
5
6
Air
Air
Groundwater
Groundwater
Post-Institutional Control Scenario (2092 lo 2121)
Resident adult— 200 meters
Resident child— 200 meters
Resident adult— 500 meters
Resident chiW-500 meters
Resident adult— 5,200 meters
Resident child-5,200 meters
a. Risks are calculated for three different distances
2092-2121
2092-2121
2092-2121
2092-2121
2092-2121
2 in 10.000 (2 x W4)
-d
2 in 10,000 (2 x ID"4)
_<1
2 in 10,000 (2 x 10"4)
2092-2221 -d
from receptor to center of SDA. 200 meters => 656 ft,
b. The NCP defines an acceptable level of carcinogenic risk as less
1 x 10*).
than 1 additional incidence of cancer in
6
5
3
7
5
5
500 meters = 1,640
10,000 to 1,000,000
Groundwater •
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
ft, 5,200 meters = 17,060 ft.
individuals (i.e., 1 x IO"4 to
c. A hazard index (the ratio of the level of exposure to an acceptable level) greater than 1 indicates that there may be concern for noncarcinogenic effects.
Hazard indices listed are cumulative across all exposure pathways.
d. Carcinogenic risks are calculated for the population exposed over a period of time to contaminant concentrations for which cancer is typically observed.
e. Concentration of CCI4 in the SRPA beneath the SDA is predicted by the model to peak in the year 2071 at a concentration of about 125 mg/m3 (ppb).
However, ingesiion of groundwater by workers during the institutional control scenario was not considered in the risk assessment due to institutional controls
preventing the use of SRPA water above MCLs by workers.
-------
groundwatcr during the latter part of the institutional control period and the post-institutional control
period. The risk increases with increasing concentrations of contaminants in groundwatcr. Therefore,
organic contamination in the vadosc zone, if not addressed by a remediation alternative, could migrate
to the SRPA and contaminate the groundwatcr to a degree that results in risks to human health of
2 x 10"4, which is slightly greater than the acceptable risk range. In addition, concentrations of CC14,
TCE, and PCE in groundwater are predicted to peak above their respective MCLs (see Figure 9).
The hazard indices estimated for the current period are less than 1 except for the worker at the
SDA boundary. The estimated hazard index of 2 for the current worker is related to outdoor
inhalation of organic contaminants. This estimate is based on conservative assumptions associated
with exposure duration and the air model used to predict outdoor concentrations of organic
contaminants. Due to the conservative nature of these assumptions, the actual hazard index for this
receptor is expected to be less than 1. Generally, hazard indices greater than 1 indicate that the
potential exists for noncarcinogenic effects to be seen in exposed individuals. For the institutional
and post-institutional control periods, hazard indices greater than 1 were calculated for each of the
residential receptors. The primary exposure routes for these hazard indices arc ingcstion of
groundwater and inhalation of organic vapors released from indoor use of groundwater.
6.1.5 Uncertainty
Risk assessments are subject to uncertainty from inventory records, sampling and analysis, fate
and transport estimation, exposure estimation, and lexicological data. Uncertainty was addressed by
using health protective assumptions that systematically overstate the magnitude of health risks. This
process is intended to bound the plausible upper limits of risk and to facilitate an informed risk
management decision. Table 8 is a summary of risk assessment uncertainty factors and their effects
on the modeling results.
6.2 Environmental Concerns
In order for organic contaminants to elicit adverse ecological impacts, credible pathways of
ecological exposure must be identified. Three potential pathways of exposure are:
• Absorption or inhalation of vapors through the airborne route
• Uptake or ingestion of groundwater containing COCs which have migrated from the
vadose zone to the saturated zone
• Direct exposure or uptake from burrowing or root penetration of the vadose zone
contamination.
Modeling suggests that the peak concentration of volatilized COCs measured at the ground
surface has already occurred and will continue to decrease with time. The groundwatcr pathway is
not currently a complete pathway because groundwatcr is not being developed for irrigation at the
Site. The concentration of COCs in groundwater are expected to peak and begin to decline during
the institutional control period. Lastly, because COC concentrations in soil were extremely low or
30
-------
Table 8. Uncertainty factors, OU7-08, INEL.
Uncertainty factor
Effect of uncertainty
Comment
Sampling and analysis
Vapor plume extent
Detection limits/COC
screening
May slightly over- or under-
estimate risk
May slightly over- or under-
estimate risk
Exclusion of surface soil from May slightly undcr-cstimate
the sampling and analysis risk
program
Since the source term is static, a
larger vapor plume would affect a
larger exposure area, but result in
reduced concentrations.
Measurements used in COC
screening had different detection
limits in the laboratory equipment
than in the field equipment.
However, since maximum
concentrations arc used in screening,
the effect is expected to be small.
Since the COCs are volatile, they
would volatilize from surface soils.
Therefore, sampling and analysis was
not conducted for this medium.
Surface soil is the subject of OU7-
05.
Fate and transport estimation
Assumed house volume and
ventilation rate
Near field indoor soil-gas
concentrations
Source term assumptions
Natural infiltration rate
Moisture content
May slightly over- or under-
estimate risk
May over- or undcr-cstimate
risk
May over- or under-estimate
risk
May over-estimate risk
May over- or undcr-cstimate
risk
The indoor concentration of soil gas
penetrating the foundation depends
on indoor ventilation.
Indoor soil-gas concentrations at 200
m were assumed equal to modeled
concentrations at 500 m, since the
model assumptions do not facilitate
near-field resolution.
The heterogeneous sources (pits)
were assumed to be a homogeneous
disk of 200 m in radius. Chloroform
may have been present in the source
term, but not recorded.
A conservative value was used for
this parameter.
This varies seasonally in the upper
vadose zone and may be subject to
measurement error.
31
-------
Table 8. (continued).
Uncertainty factor
Effect of uncertainty
Comment
Fate and transport estimation
(continued)
Modeling use of a 100 foot
screen interval
Volume of theoretical mixing
space in near-field air
. dispersion model
May over- or under-estimate
risk
May over-estimate risk
Active thickness of SRPA is 250 ft.
The initial source term area for the
vadose zone model was used,
although the surface flux will be
emitted over a larger area.
Exposure estimation
Receptor locations
May over- or under-estimate
risk
Exposure duration
May over-estimate risk
Exclusion of food pathway May under-estimate risk
Non chemical-specific
constants (e.g., exposure
parameters such as inhalation
rates, exposure duration, etc)
May over-estimate risk
Contaminant concentrations May over-estimate risk
Assumed aquifer mixing
depth of 100 ft
May over- or under-estimate
risk
Receptors were located in the
direction of highest contaminant
concentrations which would tend to
overestimate actual exposure.
However, if a resident lives on top
of the SDA, the calculated exposure
is an underestimation of actual
exposure.
The assumption that an individual
will work at the RWMC or reside at
the INEL boundary for 25 or 30
years is conservative.
VOC uptake by homegrown
vegetables is considered a negligible
exposure route.
Conservative or upper bound values
were used for all parameters
incorporated into intake calculations
Assumptions regarding contaminant
concentrations as averages centered
around peak concentrations may not
characterize actual exposures.
Wood (1991) indicates that the
active depth of the aquifer is
estimated to be 250 ft. However, for
receptors close to the source, mixing
depth is mostly dependent on the
screened interval of the well.
32
-------
Table 8. (continued).
Uncertainty factor
Effect of uncertainty
Comment
Exposure estimation
(continued)
Assumed hydraulic
conductivity of 700 ft/day
Model docs not consider
biotic decay
Exclusion of chloroform
May over- or under-estimate
risk
May over-estimate risk
May undcr-estimatc risk
Exclusion of transformation May undcr-estimate risk
products
Higher hydraulic conductivities may
send the plume to receptors faster,
but may disperse contaminants faster
as welL
Biotic decay would tend to reduce
contamination over time. However,
the modeling effort did not account
for this process.
Chloroform may be cither a source
or transformation product. Its
detection is sporadic and was not
modeled.
Not all transformation products of
the identified organic compounds
were evaluated.
lexicological data
Use of cancer slope factors May over-estimate risk
Critical toxicity values derived May over- or under-estimate
primarily from animal studies risk
Critical toxicity values derived May over- or under-estimate
primarily from high doses, risk
most exposures are at low
doses
Critical toxicity values and May over- or undcr-estimatc
classification of carcinogens risk
Potencies are upper 95th perccntile
confidence limits. Considered
unlikely to underestimate true risk.
Extrapolation from animal to
humans may induce error due to
differences in absorption.
pharmacokinctics, target organs,
enzymes, and population variability.
Assumes linear at low doses. Tend
to have conservative exposure
assumptions.
Not all values represent the same
degree of certainty. AJI arc subject
to change as new evidence becomes
available.
33
-------
Table 8. (continued).
Uncertainty factor Effect of uncertainty Comment
Toxicological data
(continued)
Lack of RfDs May under-estimate risk Inhalation RfDs are not available for
TCE
Effect of absorption May over- or under-estimate The assumption that absorption is
risk equivalent across species is implicit
in the derivation of the critical
toxicity values. Absorption may
actually vary with chemical..
Dermal absorption toxicity May slightly under-estimate The unavailability of consensus
values risk absorption values does not facilitate
comparison of absorbed dose to
toxicity constants based on
administered dose.
not detected, plants and burrowing animals are not expected to be adversely affected by COCs at the
Site. Therefore, while it is acknowledged that potential ecological receptors are currently present
on-Sitc, contact with COCs is unlikely under current Site conditions.
Consequently, an ecological risk assessment was not conducted for the OCVZ RI/FS. The
ecological impacts from OCVZ COCs will be evaluated in the comprehensive WAG 7 RI/FS
(OU7-14).
6.3 Basis for Response
Actual.or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and substantial
cndangerment to public health, welfare, or, the environment.
7. DESCRIPTION OF ALTERNATIVES
Remedial action alternatives were developed and analyzed in detail for the OCVZ operable
unit. Prior to developing alternatives, remedial action objectives were established. These objectives
and descriptions of the developed alternatives are included in the following sections.
7.1 Remedial Action Objectives
The intent of the remedial action objectives is to set measurable goals for protection of human
health and the environment. The goals arc designed specifically to mitigate the potential adverse
effects that could result from the continued migration of the vadose zone COCs to the air or
groundwatcr.
34
-------
The risk assessment indicates that there is a current and future risk to workers and a future risk
to the public due to the organic contaminants present in the vadosc zone beneath and within the
immediate vicinity of the RWMC. For workers, the primary contributing exposure route is inhalation
of air contaminated with organic vapors that migrate upward from the vadosc zone to the
atmosphere. Exposure to contaminated groundwatcr was not considered a complete exposure
pathway for current and future on-site workers due to the fact that if contaminant concentrations in
the RWMC production well exceed permissible standards, the water would be treated or water would
be supplied to workers from an uncontaminated source. For public receptors, the primary
contributing exposure route was the use of groundwater. The baseline risk assessment concluded that
future residential exposure to groundwater both on- and off-site would result in carcinogenic risks
and noncarcinogenic hazards that are unacceptable. In addition, modeling of contaminant migration
through the vadosc zone and into the SRPA indicated that contaminant concentrations in the aquifer
would continue to increase until sometime around the year 2071, at which time they would begin to
decrease (see Figure 9 in Section 6). The resultant contaminant concentrations in groundwatcr could
continue to remain above Federal and state MCLs for a period of several hundred years.
The results of the RI and baseline risk assessment indicated that the contamination of
groundwatcr due to the migration of the vadose zone organic contaminants to the SRPA will present
the most significant future risk to human health if no action is taken. Specifically, the baseline risk
assessment indicated that the highest risk to a human receptor from the inhalation of contaminants
emanating from the vadose zone is on the order of 10~5, while the highest risk from the future
ingcstion of contaminated groundwater is on the order of 10"4. The baseline risk assessment also
shows that the risk from the inhalation of vapors emanating from the subsurface is at or below the
10*6 level for all of the future risk scenarios. That is, contaminant flux to the atmosphere has already
peaked and will continue to decrease naturally. These results suggest that the primary objective of
the FS should be to develop alternatives that would prevent vapor-phase organic contaminants in the
vadose zone from reaching groundwatcr in concentrations that would result in future groundwatcr
contaminant concentrations that exceed Federal and state MCLs. The MCLs result in an overall risk
value within the acceptable range of 10"* to 10*6. As such, the primary remedial action objective, and
the focus of remedial action alternative development, is to ensure that risks to future groundwatcr
users are within acceptable guidelines and that future contaminant concentrations in the aquifer
remain below Federal and state MCLs. To ensure that this remedial action objective is met and
maintained, a long-term groundwater and soil vapor monitoring program would be conducted. The
monitoring program would be designed to provide an early indication of the possibility of future
groundwater contamination above acceptable levels.
Remedial action objectives also include the identification of preliminary remediation goals
(PRGs) that are established based on both risk and frequently used standards referred to as
Applicable or Relevant and Appropriate Requirements (ARARs). PRGs arc typically expressed as
contaminant concentrations (i.e., cleanup levels) desired after a remedial action for various
contaminated media, Contaminants associated with OCVZ arc primarily organic vapors of CC14,
TCE, PCE, 1,1,1-TCA, and chloroform present in the vadosc zone. Because there are currently no
ARAR-bascd standards available for determining cleanup levels for organic vapors in subsurface soils.
an approach using groundwatcr MCLs to estimate PRGs for OCVZ was used. Such an approach
relied on the contaminant fate and transport modeling, which was used as part of the baseline risk
assessment, to estimate cleanup levels that would satisfy the primary remedial action objective. The
fate and transport modeling predicts PRG levels for CCI4, which is the COC present in the most
35
-------
significant concentrations, that may range from 30 to 200 ppmv, depending on the location within the
vadose zone. The other COCs arc predicted to have similar PRG levels that also vary depending on
the location within the vadose zone. The PRGs only apply to alternatives that focus on removal of
the COCs from the vadose zone; however, the remedial action objectives apply to any alternative.
The PRG range of 30 to 200 ppmv for CC14 is an estimate based on information available to
date. Any alternative that removes COCs from the vadose zone would also include steps to further
define characteristics (i.e., extent and concentrations) of the vadose zone COCs. Better definition
of the COC characteristics will allow PRGs to be refined. The future refinement of PRGs will be
agreed upon by the DOE, EPA, and the IDHW. Such a refinement will increase the three agencies'
confidence that remedial action objectives can be met and maintained. It should be noted that PRGs
for the OCVZ operable unit cannot be identified as discrete COC concentrations in the vadose zone.
Alternatives designed to achieve the remedial action objectives were assembled using
combinations of the following general response actions.
• Institutional Controls—includes soil vapor and groundwater monitoring. Monitoring is
effective for observing changes in vadose zone as well as groundwater contaminant
concentrations and in identifying imminent hazards..
• Containment—only option for containment that can be implemented for the OCVZ is
capping. A cap over the SDA may effectively prevent water from reaching the source pits
and contributing to leaching of contaminants; thereby, minimizing the migration of
contaminants to the environment. A cap would minimize migration of contaminants to the
atmosphere at the surface of the SDA.
• Vapor Extraction—includes methods to extract vapor from the various regions of the
vadose zone beneath the RWMC
• In-Situ Treatment of Vapors—only reasonable option for in-situ treatment is
bioremediation.
• Ex-Situ Treatment of Vapors—includes several options for biological, physical, thermal, and
chemical treatment of vapors recovered from the vadose zone. Ex-situ treatment would
attempt to reduce the toxicity, mobility, and volume of recovered contaminants.
7.2 Summary of Alternatives
In accordance with Section 121 of CERCLA, the Feasibility Study (FS) identified alternatives
that (a) achieve the stated remedial action objectives, (b) provide overall protection of human health
and the environment, (c) meet ARARs, and (d) arc cost-effective.
The alternatives evaluated in the FS for OCVZ were Alternative 0—No Action; Alternative 1—
Containment of Vadose Zone Vapors by Capping; Alternative 2—Extraction/ Treatment by Vapor
Vacuum Extraction (WE); Alternative 3—Extraction/Treatment by WE with Vaporization
Enhancement; and Alternative 4—In Situ Bioremediation. Alternatives 3 and 4 propose to use a
catalytic oxidation unit to treat vapor. This technology is fairly new and may be substituted with other
36
-------
technologies such as carbon adsorption, biological treatment, ultraviolet treatment, etc. if
implementation of the catalytic oxidation system proves to be ineffective or difficult due to site-
specific circumstanccs.AUhough Alternative 4 was developed, it was not analyzed in detail with the
other alternatives since it was decided early in the FS process that in situ biorcmcdiation would be
ineffective as well as very difficult to implement in the fractured basalt region beneath the RWMC.
Descriptions of Alternatives 0 through 3 are provided in the following sections.
Substantive action-specific ARARs are identified for Alternatives 1-3. These ARARs, are listed
in Table 9. Note that there are no action-specific ARARs for the No Action Alternative. The
majority of ARARs focus on the management of materials and waste, including the regulation of air
emissions from vapor treatment and remediation activities at the OCVZ operable unit. Specific
requirements arc:
• Characterization of hazardous wastes that may be generated from remediation activities
• Control of emissions from vapor treatment and recovery systems
• Measures to control fugitive dust from well drilling and earth moving.
No chemical-specific ARARs are identified for the considered alternatives. Regulations have not
been promulgated specific to soil cleanup levels for vapor-phase contaminants. Also, no location-
specific ARARs are identified as there are no known threatened and endangered species, wetlands,
rivers, or floodplains located in the area of potential remedial activities under the considered
alternatives.
Conservative calculations of organics in or contacting equipment demonstrate that
concentrations by weight of hazardous air pollutants are well below the threshold criteria of
applicability for the National Emission Standards for Hazardous Air Pollutants (NESHAP) program
involving equipment leaks (40 CFR 61240).
7.3 Alternative 0-No Action
Under this alternative, no attempt would be made to contain, treat in place, or extract and treat
the organic contaminants present within the vadose zone. Instead, only long-term groundwater and
soil vapor monitoring would be implemented. Groundwater monitoring is necessary to detect
contaminant concentrations in the SRPA. Soil vapor monitoring is necessary to track the migration
of contaminant vapors in the vadose zone. Changes in contaminant concentrations in groundwater
and soil vapor would be evaluated to determine whether measures must be taken to minimize
potential risks to public health and the environment It was assumed that monitoring would continue
for a period of 30 years under the No Action Alternative. This alternative was a "baseline" case
against which the other alternatives were compared.
There are no ARARs identified for the No Action Alternative. Net present value costs for
implementing groundwater and soil vapor monitoring under this alternative for the next 30 years are
estimated to be $4.1 million.
37
-------
Table 9. Summary of ARARs and TBC criteria for OCVZ alternatives.
Statute
Regulation
Alternative 0
no action
Alternative 1
containment
Alternative 2
extraction/
treatment by
WE
Alternative 3
extraction/treatment
by WE with
enhancement
RCRA
Gean Air Act
Idaho Toxic Air
Pollutants Non-
Carcinogenic
Increments
Idaho Toxic Air
Pollutants
Carcinogenic
Increments
IDAPA $ 16.01.050.5005, (40
CFR 261.10, 261.20-261.24)
"Idaho Rules, Regulations and
Standards for Hazardous
Waste"
40 CFR 264.600 Subpart X,
Miscellaneous Units
40 CFR 61.92, "National
Emission Standards for
Radionuclide Emission from
DOE Facilities"
IDAPA 516.01.01.577, Not ARAR
"Ambient Air Quality Standards
for Specific Air Pollutants"
IDAPA 516.01.015.85 Not ARAR
Not ARAR Not ARAR
NotARAR
NotARAR
IDAPA § 16.01.015.86
R/Yes
Not ARAR A/Yes
Not ARAR A/Yes
Not ARAR Not ARAR A/Yes
R/Yes
NotARAR R/Yes
Not ARAR A/Yes
R/Yes
A/Yes
A/Yes
A/Yes
A/Yes
-------
Table 9. (continued).
Statute
Regulation
Alternative 0 Alternative 1 Alternative 2
no action containment
extraction/
treatment by
WE
Alternative 3
extraction/treatment
by WE with
enhancement
Idaho Rules for
Control of Fugitive
Dust
IDAPA § 16.01.01.651
Idaho Demonstration IDAPA § 16.01.01.210.10
of Preconstruction
Compliance with
Toxic Standards
DOE Order
DOE 5820.2A, "Radioactive
Waste Management"
A = Applicable
R = Relevant and Appropriate
TBC = To Be Considered.
Not ARAR A/Yes
TBC
TBC
A/Yes
Not ARAR Not ARAR R/Ycs
TBC
A/Yes
R/Yes
TBC
-------
7.4 Alternative 1—Containment of Vadose Zone Vapors by Capping
Alternative 1 consists of the installation of a cap over the SDA to minimize infiltration of
rainwater, surface water, and snowtnclt into the subsurface. Capping would reduce the amount of
infiltrating moisture that reaches the waste buried in the SDA and contributes to downward migration
of organic contaminants in the vadose zone. Capping is the systematic covering of an area with layers
of soil, clay, and/or synthetic material that would be used, in this case, to provide a relatively
impermeable barrier to surface water. Typical applications of capping are municipal landfills where
contaminated water (i.e., leachate) is formed via infiltrating surface water. A cap of the SDA would
consist of three layers of earthen fill over the entire 88-acre surface of the SDA.
Under Alternative 1, removal and treatment of organic contaminants would not occur. By
minimizing the infiltration of water, capping would decrease the contact of water with organic
contaminants at shallow depths directly beneath the disposal area; thus, migration of organic
contaminants dissolved in infiltrating moisture would be reduced. However, even with capping,
contaminants would continue to migrate both vertically and laterally in the vadose zone, primarily in
the vapor phase.
The only ARAR identified for this alternative is Idaho Rules for Control of Fugitive Dust
(IDAPA § 16.01.01.651). This ARAR would be met during the construction of a cap through
appropriate engineering controls to minimize dust generation.
The net present value cost of Alternative 1 is estimated to be $433 million, including a nine
million dollar contingency to cover unanticipated costs associated with capping materials acquisition.
It is expected that it would take no more than 20 workers five years to construct the cap. As such,
there are no significant socio-economic impacts associated with this alternative. Periodic maintenance
of the cap would be needed to maintain its integrity. In addition, soil vapor and groundwatcr
monitoring would be conducted to monitor the migration of organic contaminants in the vadose zone
and SRPA.
7.5 Alternative 2—Extraction/Treatment by WE
Alternative 2 would use WE to remove organic vapors from the vadose zone. Extracted vapors
would subsequently be treated at the surface. This alternative would utilize the existing WE
extraction well and several additional extraction wells which would be located in areas of the SDA
known to have significant levels of organic vapors in the vadose zone. The existing WE system was
installed to determine the viability of WE as a technology for the recovery and treatment of the
vadose zone contaminants. The system consists of one vapor extraction well, a blower, and a carbon
adsorption vapor treatment system. The extraction well is configured to draw vapors at a flowrate
of approximately 200 cubic feet per minute from the 110-foot sedimentary interbcd. This
configuration recovers vapor .organic contaminants from above and below the interbcd. Figure 10
shows a conceptual cross-sectional view of the existing WE system with geological features of the
vadose zone and a .conceptual representation of the vapor contaminant plume included.
40
-------
Sediment/Basalt Interface
at Approximately 30 ft.
Below Surface
WE Recovery/Treatment System
In Representative
-u^—--^ — Waste Pits
I
Region of
Fractured
Basalt
110 (t Sedimentary
Interbed
240 ft. Sedimentary
Interbed
•: Screened Interval
: tor Vapor Recovery
Vadose
Zone
I
I
r
1100
i» r
I 0
Representative
Vapor Contaminant
Plum*
MO 800 900
Snake River Plain Aquifer Is 580 feet below
th* surface of *ie Subsurface Disposal Area
Legend
Surfldar. Sediments
ppm • parts per million carbon tetrachlcrlde
^^•^- Sedimentary Interbed Material
Figure 10. Schematic cross section of WE system showing approximate extent of vapor plume and
vapor extraction well.
Under a phased approach to Alternative 2, the existing WE system would be augmented with
additional vapor extraction wells, monitoring wells, and vapor treatment equipment. The first phase
would include the installation of five additional vapor extraction wells (see Figure 11) to augment the
contaminant recovery capability of the existing vapor extraction well. Additional vapor treatment
units and vapor monitoring wells would support these five wells. Subsequent phases may also include
more vapor extraction wells, monitoring wells, passive venting wells, and vapor treatment units. In
order to clarify the range of cost for Alternative 2, it was assumed that a second phase would involve
the installation of four additional vapor extraction wells and accompanying support equipment, for
a total of 10 wells (including those installed under the first phase). A maximum number of fourteen
vapor extraction wells and accompanying support equipment would be expected under a third and
final phase of Alternative 2. A more detailed discussion on the use of phases under Alternative 2
is included below. In addition to contaminant recovery and treatment. Alternative 2 would include
long-term soil vapor and groundwatcr monitoring.
Each vapor extraction well would be linked to a catalytic oxidation unit or equivalent vapor
treatment system. Such a treatment system could typically achieve a sufficient contaminant
destruction efficiency for the extracted vapors, and be capable of maintaining an airflow that would
41
-------
o< •ximng v«por
v«cuum -•p**-*""
Up and
O Vapor extraction vraQ
location
O Son vapor monitoring
w«a location
= = = Road
• • * Fence
*4 Pit Number
Figure 11. Alternative 2 Phase I vapor extraction/monitoring wells.
range between 125 and 150 cfm. Catalytic oxidation is basically a thermal process that is capable of
converting chlorinated hydrocarbons (such as the CC14, TCE, PCE, 1,1,1-TCA, and chloroform
present at OCVZ) into carbon dioxide, water, and hydrochloric acid (HC1) gas. It accomplishes
thermal destruction at a relatively low temperature in the presence of a catalyst. It is expected that
under a possible third phase of this alternative, which would entail the most extensive use of catalytic
oxidation, the HC1 emission would be below applicable air discharge requirements, even without
scrubbing for acid gas removal. Overall, catalytic oxidation was favored as the representative process
option for'air treatment because of its proven ability to destroy the types of contaminants present at
OCVZ, its availability in modular compact units that could be placed adjacent to each vapor
extraction well, and its relatively low operation and maintenance costs. Potentially, one catalytic
oxidation unit would be dedicated to each extraction well due to the large distances between wells.
The units would require fuel such as propane to maintain the contaminant oxidation process.
The FS considered other vapor treatment technologies such as biological treatment, ultraviolet
treatment, and carbon adsorption. Based on available performance data, biological and ultraviolet
treatment would require further development in order to be a viable vapor treatment option for the
large-scale application that would be required under Alternative 2. Carbon adsorption has already
been demonstrated as a viable vapor treatment option during the OCVZ treatability studies; however,
difficulties associated with the handling and regeneration of contaminant-saturated carbon must be
resolved in order to utilize this technology for large-scale vapor treatment at the RWMC. Further
investigation of available air treatment technologies that would be most appropriate to support WE
at OU 7-08 would continue through the design of Alternative 2.
42
-------
Each of the ARARs identified for this alternative would be met through appropriate
engineering controls such as vapor treatment. Through the use of catalytic oxidation for vapor
treatment, it is expected that no residual treatment wastes would be generated under Alternative 2.
Net present value costs for implementing this alternative range from $12.9 to $32.4 million. The cost
range corresponds to first phase operations through third phase operations for a period of two years
to six years, respectively. It has been assumed that cleanup goals would be attained at some point
in the zero to six year timcframc. The costs also include an assumption of thirty years for soil vapor
and groundwater monitoring. It is estimated that a maximum of ten workers would be required to
complete this alternative. As such, there would be no significant socio-economic impacts associated
with this alternative.
Phases of Alternative 2
The potential progression of Alternative 2 to a second and third phase would be dependent on
the ability of the vapor extraction system to achieve the remedial action objectives, i.e., ensure that
risks to future groundwater users are within acceptable guidelines and that future contaminant
concentrations in the aquifer remain below Federal and state safe drinking water standards. The -
performance of Alternative 2 would be reviewed on a two year (24 month) cycle, with each phase
of operation under the alternative expected to last at least two years. The actual duration of each
phase would be dependent on elements such as equipment procurement and installation that may be
involved with each transition; however, the following description of the review cycle assumes that
transitions would occur in a timely fashion every 24 months.
The first review would commence after 18 months of operation under the first phase. Data
accumulated over these 18 months would be analyzed and a decision made by DOE, EPA, and the
IDHW as to what would comprise the second phase of Alternative 2 (if a second phase is necessary
to attain remedial action objectives). Alternative 2 would continue under first phase operations up
to 24 months, at which time, after the data analysis period, a transition to the second phase would
occur. Data analyzed would be relevant to the attainment of remedial action objectives
(c.g., contaminant recovery rates, equilibrium contaminant concentrations in the vadose zone, etc.).
Considerable engineering judgement would be used in deciding what modifications to the first
phase would be made to continue Alternative 2 into a second phase in order to achieve remedial
action objectives. Potential options for continuing Alternative 2 into a second phase include:
(1) continuing operation with no changes to the first phase of operation; (2) adding more vapor
extraction wells; (3) extracting from different depths within existing extraction wells; (4) converting
monitoring wells into extraction wells; and (5) adding and/or converting existing wells to passive
venting wells. These options and others not currently identified may be carried out singly or in
combinations, with the intent being to ensure that Alternative 2 achieves remedial action objectives.
The need for additional phases beyond a second phase would be evaluated using the same
general approach as outlined above for the transition between the first and possible second phase.
If a second phase is implemented, then the data evaluation and decision regarding a possible third
phase would begin 18 months into the second phase (i.e., 42 months from the start of Alternative 2)
with the third phase beginning, if necessary, approximately 48 months from the start of Alternative 2.
Potential options for continuing Alternative 2 into a third phase would be similar to those listed
43
-------
above. This type of phased operation would continue through phases lasting 24 months each until
remedial action objectives arc achieved.
7.6 Alternative 3—Extraction/Treatment by WE with
Vaporization Enhancement
Alternative 3 would include WE (as described for Alternative 2) as the primary contaminant
recovery method with radio frequency heating to enhance the vaporization of organic contamination
in the vadose zone. Radio frequency heating would target contaminants that have partitioned to the
aqueous phase in the vadose zone (Le., organic contaminants dissolved in soil moisture or perched
water) or have adsorbed onto material in the sedimentary intcrbeds. Radio frequency heating would
use strategically placed antennae in boreholes to raise the temperature in discrete areas of the
subsurface. The .increased temperature would induce volatilization of the organic contaminants.
Volatilized contaminants would then be recovered by the WE system. The temperature in the
subsurface would be raised gradually to allow the WE system to recover organic contaminants as
they volatilize. The WE system under Alternative 3 would include 14 vapor extraction wells and
14 boreholes installed to the 110-foot interbed to accommodate the insertion of the radio frequency
heating antennae.
Each of the ARARs identified for this alternative would be met as discussed for Alternative 2.
Net present value costs for implementing Alternative 3 are estimated to be $59.9 million. This cost
is based on operation of a full network of WE wells and no more than two radio frequency heating
antennae operating at any given time over a period of six years. The costs include an assumption of
thirty years for soil vapor and groundwater monitoring. It is estimated that no more than ten workers
would be required to complete this alternative. As such, there are no significant socio-economic
impacts associated with Alternative 3.
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
CERCLA guidance requires that each remedial alternative be compared according to nine
evaluation criteria that have been developed to serve as a basis for conducting the detailed analyses
of alternatives and for subsequently selecting an appropriate remedial action. The evaluation criteria
arc divided into three categories: (1) threshold criteria that relate directly to statutory findings and
must be satisfied by each chosen alternative; (2) primary balancing criteria that include long- and
short-term effectiveness, implementability, reduction of toxicity, mobility, and volume, and cost; and
(3) modifying criteria that measure the acceptability of the alternatives to State agencies and the
community. The following sections summarize the evaluation of the candidate remedial alternatives
according to these criteria.
8.1 Threshold Criteria
The remedial alternatives were evaluated in relation to the threshold criteria: overall protection
of human health and the environment and compliance with ARARs. The threshold criteria must be
met by the remedial alternatives (except the No Action Alternative) for further consideration as
potential remedies.
44
-------
8.1.1 Overall Protection of Human Health and the Environment
This criterion addresses whether an alternative provides protection of human health and the
environment and describes how risks posed through each exposure pathway are eliminated, reduced,
or controlled through treatment, engineering controls, or institutional controls.
Alternatives 2 and 3, Extraction/Treatment by WE and Extraction/Treatment by WE with
Vaporization Enhancement, respectively, satisfy the criterion of overall protection of human health
and the environment The alternatives accomplish this by recovering and treating organic vadose
zone contaminants, thus, preventing unacceptable levels of contaminant migration to the SRPA and
also potentially reducing the mass flow of contaminants to the surface soils and atmosphere above
theRWMC.
Alternative 1, Containment of Vadose Zone Contaminants by Capping, also satisfies this
criterion to the degree that it protects human health by potentially reducing the level of contaminant
migration to the SRPA and by reducing the mass flow of contaminants to the atmosphere at the
surface of the RWMC It is not clear, however, how much of a reduction in the amount of organic
contaminants reaching the SRPA would occur under this alternative. This uncertainty stems in part
from the potential migration of contaminants at greater depths that may still be affected by water
infiltrating from areas outside of the SDA, Capping would not affect organic contaminants in the
vadose zone that have migrated laterally beyond the boundary of the SDA. Although not considered
an ARAR for this OU, it is likely that contaminant concentrations in the aquifer would exceed MCLs
in the future under this alternative.
Overall, each of the alternatives, with the exception of Alternative 0, No Action, would result
in a lifetime excess cancer risk within the acceptable range of 1 x 10"4 to 1 x 10"*. Also, hazard
indices associated with the COCs would be reduced to acceptable levels. Alternative 1 would
accomplish this by reducing the migration of contaminants to the SRPA through a reduction in
moisture infiltration at the surface of the SDA. Alternatives 2 and 3 would accomplish this by
recovering and treating the most significant levels of vadose zone contaminants present. Although
there is some uncertainty in the modeling results, it is believed that the No Action Alternative would
not satisfy the criterion of Overall Protection of Health and the Environment
8.1.2 Compliance with ARARs
CERCLA, as amended by SARA, requires that remedial actions for Superfund sites comply with
identified substantive applicable requirements identified under Federal and state laws. Remedial
actions must also comply with the requirements of laws and regulations that are not directly
applicable but are relevant and appropriate, in other words, requirements that pertain to situations
sufficiently similar to those encountered at a Superfund site so that their use is well suited to the site.
Combined, these are referred to as ARARs. State ARARs arc limited to those requirements that
arc (a) promulgated, (b) uniformly applied, and (c) arc more stringent than Federal requirements.
Compliance with ARARs requires evaluation of the remedial alternatives for compliance with
chemical, location, and action-specific requirements.
Three of the remedial alternatives considered for OCVZ comply with the identified ARARs
through engineering controls and operating procedures. ARARs arc not identified for the No Action
45
-------
Alternative since no treatment or containment activities are proposed. with this alternative. A
summary of the ARAR analysis is presented in the Summary of Alternatives section and listed in
Table 9. The action-specific ARARs focus on management of materials and waste and the regulation
of air emissions that may result from remediation activities at the OCVZ operable unit—no chemical-
and location-specific ARARs are identified. The specific substantive requirements of the action-
specific ARARs are:
• Identification of hazardous wastes that may be generated from remediation activities
• Control of emissions from vapor treatment and recovery systems
• Measures to reduce potential fugitive dust from well drilling and capping activities.
8.2 Balancing Criteria
Each alternative that satisfies the threshold criteria is evaluated against each of the five
balancing criteria. The balancing criteria are used in refining the selection of the candidate
alternatives for the site. The five balancing criteria are: (1) long-term effectiveness and permanence;
(2) reduction of toxicity, mobility, or volume through treatment; (3) short-term effectiveness;
(4) impleraentability, and (5) cost Each criterion is further explained in the following sections.
8.2.1 Long-Term Effectiveness and Permanence
This criterion evaluates the long-term effectiveness of alternatives in maintaining protection of
human health and the environment
Alternatives 2 and 3 provide the greatest level of long-term effectiveness and permanence by
targeting for recovery and treatment vapor contaminants present throughout the upper portion of
the vadose zone. Alternative 2 provides a slightly lower level of long-term effectiveness than
Alternative 3 because it does not incorporate an option to enhance contaminant recovery. In other
words. Alternative 2 has a slightly greater potential than Alternative 3 to leave untreated
contaminants in the vadose zone, although this potential is considered to be fairly small because the
RI did not indicate that there was a significant amount of the COCs partitioned to perched
groundwater and/or the sedimentary interbeds; i.c~, regions of the vadose zone that would be targeted
for enhanced recovery if contaminants were prevalent there. A degree of risk would remain with
Alternatives 2 and 3 because it is not possible to remove and treat all of the vadose zone organic
contaminants.
Alternative 1 also provides long-term effectiveness and permanence, but to a lesser degree than
Alternatives 2 and 3 due to uncertainties associated with its performance and due to its lack of
contaminant removal and treatment That is. Alternative 1 is a less reliable remedy, and the degree
of risk remaining after it is implemented would be greater than the risk remaining under
Alternatives 2 or 3.
The No Action Alternative provides the lowest level of long-term effectiveness and permanence
as it provides no recovery or measures to reduce the migration of contaminants through the vadose
zone toward the SRPA.
46
-------
8.2.2 Reduction of Toxicity, Mobility, or Volume through Treatment
This criterion addresses the statutory preference for selecting remedial actions that employ
treatment technologies, which permanently reduce toxicity, mobility, or volume of the hazardous
substances as their principal clement.
Alternatives 2 and 3 each provide a reduction in the volume of organic contaminants present
in the vadosc zone. The reduction in volume is accomplished by removing vapors with a WE system
and treating the removed organic contaminants. Alternative 3 offers an advantage over Alternative 2
because it has a greater potential to achieve the necessary organic contaminant removal more
effectively by enhancing the recovery of the WE system through heating of areas of the vadose zone.
The overall improvement in contaminant recovery afforded by Alternative 3 over Alternative 2 cannot
be fully evaluated at this time. It is reasonable to assume, however, that some benefit to contaminant
recovery would be realized.
—«•
Alternative 1 does not provide any treatment of the contaminants present; however, it does limit
the mobility of contaminants present in the vadose zone by minimizing the infiltration rate directly
below the SDA. The No Action Alternative provides no reduction in toxicity, mobility, or volume
of the contaminants present in the vadosc zone.
8.2.3 Short-Term Effectiveness
Short-term effectiveness addresses the effects of each alternative during its construction and
implementation phase until remedial action objectives are achieved. Under this criterion, the
alternatives are evaluated with respect to their impacts on human health and the environment during
implementation of the alternative.
In general, alternatives requiring the least amount of construction and/or operation and handling
of equipment, residual wastes, etc. rank the highest in terms of short-term effectiveness. As such, the
No Action Alternative ranks high under this criterion because it requires no additional on-site
activities and does not result in additional acute hazards to the public or the environment.
Alternative 2 ranks slightly higher than Alternative 3 because it is simpler in terms of the
amount of equipment and operations personnel involved. Each of these alternatives has a slight
potential for worker risks through physical hazards associated with borehole installation and
operation/maintenance of the contaminant treatment system. Alternative 3 has additional worker risk
associated with .the operation of the radio frequency heating system (e.g., electrical and heating
hazards). There would be no significant increase in potential risks to the public under any of these
treatment alternatives. This is mainly due to the fact that the bulk of the contaminants would remain
isolated from the surface environment in their present form within the vadose zone beneath the
RWMC.. Those contaminants brought to the surface would be controlled by a surface-based vapor
treatment system designed to destroy contaminants on-site. The operation of this treatment system
would be monitored to ensure that releases of contaminants to the environment do not exceed
acceptable air emission levels.
Alternative 1 ranks the lowest of the considered alternatives under this criterion. This
alternative would require a significant level of construction activities associated with the installation
47
-------
of a cap over the SDA. Potential risks to workers, including risks associated with the transportation
of needed construction materials to the RWMC, outweigh all other elements under short-term
effectiveness.
8.2.4 Implementabilrry
The implementability criterion has the following three factors requiring evaluation: (1) technical
feasibility, (2) administrative feasibility, and (3) the availability of services and materials. Technical
feasibility requires an evaluation of the ability to construct and operate the technology, the reliability
of the technology, the ease of undertaking additional remedial action (if necessary), and monitoring
considerations. Administrative feasibility generally includes an evaluation of the coordination of
actions between agencies, planning, and personnel training. In terms of services and materials, an
evaluation of the following availability factors is required: necessary equipment and specialists,
prospective technologies, and cover materials.
Each of the alternatives retained for detailed evaluation is implementabie. Alternative 3 ranks
lower than Alternatives 2 or 0 for implementability because of its slightly greater complexity in
equipment procurement, installation, and operation. Alternative 1 ranks lower than all of the
alternatives because of potential difficulties associated with construction of the cap, including:
coordination with potential cleanup actions for other OUs at the RWMC (this is an administrative
difficulty) and procurement of extensive amounts of materials.
Long-term monitoring under these alternatives would detect any serious failure in recovering
or containing vadose zone contaminants, allowing appropriate steps to be taken to preclude
significant exposures to contaminated grbundwater from the SRPA. Each of the alternatives ranks
equally with regard to the implementability of a long-term monitoring program.
8.2.5 Cost
In evaluating project costs, an estimation of the net present value of capital costs and operation
and maintenance costs is required. In accordance with CERCLA guidance, the costs presented are
estimates (Le^ -30% to +50%). Actual costs could vary based on the final design and detailed cost
itemization. The cost estimates for the alternatives analyzed for OCVZ are presented in Table 10.
Note that the costs presented for Alternative 2 are provided for each of the three phases of
operation that may be implemented. The total cost of each phase is cumulative in that it includes
costs from each prior phase.
8.3 Modifying Criteria
The modifying criteria arc used in the final evaluation of remedial alternatives. The two
modifying criteria are state and community acceptance. For both of these criteria, the factors that
arc considered include the elements of the alternatives that are supported, the elements of the
alternatives that are not supported, and the elements of the alternatives that have strong opposition.
48
-------
Table 10. OCVZ alternative cost estimates (net present value).
Alternative 2
Alternative 0
Cost clement (no action) Alternative 1 Phase I Phase II Phase III Alternative 3
Construction
Operation
and
Maintenance
Post-Closure
Monitoring
Total
0
0
4.069.000
4,069.000
39.118.000
140.000
4,069.000
43330,000
3,013,000
4,955,000
4,888,000
12,860.000
5,036,000
11,443,000
5,495,000
21,970.000
6.893,000
19.071,000
6393.000
32360,000
8,296,000
45,211,000
6.403,000
59,910.000
8.3.1 State Acceptance
The IDHW concurs with the selected remedial alternative, Extraction/Treatment by WE. The
IDHW has been involved in the development and review of the RI/FS report, the Proposed Plan, this
ROD. and other project activities such as public meetings.
8.3.2 Community Acceptance
This assessment evaluates the general community response to the proposed alternatives
presented in the Proposed Plan. Specific comments are responded to in the attached Responsiveness
Summary portion of this document
9. SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the detailed analysis of alternatives,
and public comments, DOE-ID, EPA, and IDHW have selected Alternative 2— Extraction/Treatment
by WE as'the most appropriate remedy for OCVZ, OU 7-08 at the RWMC In terms of public risk,
fate and transport modeling indicates that there is a potential unacceptable risk to future residential
receptors using groundwater beginning at about the year 2062. The modeling also indicated that
Federal and state drinking water standards would be exceeded for CCl4, TCE, and PCE due to the
migration of these contaminants to the SRPA. Drinking water standards could potentially be
exceeded for these contaminants beginning in about 1997 and extending for several hundred years.
The exposure of hypothetical future residents to contaminants in groundwater led to the selection
of Alternative 2. The extraction of the most significant concentrations of contaminants from the
vadosc zone with subsequent treatment of the contaminants will reduce the amount of contaminants
that will migrate to the SRPA. Extraction/treatment by WE is believed to be the best alternative
for minimizing public risk and providing long-term protection of the SRPA. The success of the WE
trcatability study conducted at the RWMC supports the selected remedy. The phased approach of
the selected remedy provides a high level of assurance that remedial action objectives will be achieved
in a cost-effective manner.
49
-------
9.1 Extraction/Treatment by WE Description
The major components of Alternative 2—Extraction/Treatment by WE include vapor extraction,
vapor treatment, and institutional controls such as long-term subsurface vapor and groundwater
monitoring. The selected alternative is believed to provide the best balance of trade-offs among the
alternatives with respect to the nine CERCLA evaluation criteria. DOE-ID, EPA, and IDHW
believe the preferred alternative is protective of human health and the environment, complies with
applicable federal and state regulations, and is cost-effective.
Alternative 2 focuses on the extraction of vapor-phase organic contaminants from the vadose
zone beneath the RWMC through the use of WE. Alternative 2 will commence with extraction via
the existing vapor extraction well that supported WE tests and five additional vapor extraction wells
located to recover the most significant concentrations of vapor-phase organic contaminants from the
vadose zone (see Figure 11). This arrangement of six vapor extraction wells is considered the first
phase of Alternative 2. Extracted vapors will be treated at the surface to destroy the organic
contaminants. Vapor monitoring wells will also be installed to monitor changes in contaminant
concentrations in the vadose zone as a result of the vapor extraction operations. If, following an
evaluation of the implemented remedy (approximately two years after implementation), the agencies
conclude that data from modeling and monitoring show that vadose zone contamination is not being
sufficiently reduced to prevent Federal and state MCLs from being significantly exceeded in the
aquifer (see Section 92), additional phases of Alternative 2 may be proposed. It is expected that
there would be no need for Alternative 2 to be expanded beyond a third phase of operation. A third
phase could entail the operation of up to approximately fourteen vapor extraction wells (assumed for
cost estimating purposes) located at and within the vicinity of the RWMC A detailed description
of the use of phases under Alternative 2 is provided in Section 7.5 of this ROD.
In addition to the extraction and treatment of the vadose zone contaminants, Alternative 2 will
include long-term groundwater and soil vapor monitoring to confirm the ability of the vapor
extraction system to prevent contaminants from migrating to the SRPA at levels that would result in
unacceptable groundwater contaminant concentrations. Such monitoring will continue after
remediation to verify that organic contaminant concentrations in the vadose zone and groundwater
remain below acceptable levels.
9.2 Remediation Goals
The purpose of Alternative 2 is to reduce the concentration of organic contaminants presently
in the vadose zone and, consequently, the amount of contaminants reaching the SRPA in the future.
This reduction in organic contaminants will ensure that risks to future groundwater users are within
acceptable guidelines and that future contaminant concentrations in the aquifer remain below Federal
and state MCLs.
The alternative will be designed so that the remedial system achieves the remedial action
objectives and associated PRGs. The PRGs have been estimated through fate and transport
modeling as vadose zone vapor contaminant concentrations that will not result in future groundwater
contaminant concentrations exceeding Federal and state MCLs. The PRG for the contaminant
present in the most significant concentrations, CCI4, is approximately 30 to 200 ppmv, depending on
50
-------
the location within the vadosc zone. The other vadosc zone contaminants have similar cleanup goals.
Contaminants remaining in the vadose zone after implementing Alternative 2 will not result in
unacceptable future risks to human health and the environment, nor will they result in a violation of
Federal and state MCLs.
The PRO range of 30 to 200 ppmv for CC14 is strictly an estimate of the CC14 concentration,
which is based on information available to date, that will enable the remedial action objectives to be
achieved. It should be noted that PRGs for the OCVZ operable unit cannot be identified as discrete
COC concentrations in the vadose zone because of: (1) the complex relationship between vadose
zone COC concentrations and future groundwater COC concentrations, and (2) the lack of regulatory
driven standards for the COCs in vadose zone soils. During the implementation of the selected
remedy, information will be obtained that will allow concentrations of the vadosc zone COCs to be
further defined. A better definition of the COC concentrations will allow PRGs to be refined, i.e.,
the targeted concentrations at various locations throughout the contaminated region of the vadose
zone could be identified more specifically, and attainment of remedial action objectives more readily
determined. The future refinement of PRGs will be agreed upon by the DOE, EPA, and IDHW.
Such a refinement will increase the three agencies' confidence that remedial action objectives, which
will not change, can be met and maintained.
Flexibility in cleanup goals for the OCVZ is essential for the selected remedial alternative given
the level of additional information on the OCVZ that is expected to be obtained during each of the
potential phases of Alternative 2. The cleanup goals will require a significant amount of re-evaluation
during the course of remedial action. A re-evaluation will be focused primarily on fate and transport
modeling, which wfll take into account information gathered while carrying out the selected remedy
as well as any future cleanup actions that may take place with the pits and trenches at the SDA.
Changes in fate and transport modeling will likely have an impact on the PRGs for the OCVZ.
For those remedial actions that allow hazardous substances to remain on-site, Section 121 (c)
of CERCLA requires that a review be conducted of the remedy within five years after initiation of
the remedial action and at least once every five years thereafter. The purpose of this review is to
evaluate the remedy's performance—to ensure that the remedy has achieved, or will achieve, the
remedial action objectives set forth in the ROD and that it continues to be protective of human
health and the environment During implementation of Alternative 2 at OCVZ, the remedy's
performance will be reviewed on a two year (24 month) cycle, with each phase of operation under
Alternative 2 expected to last at least two years. The review cycle is detailed under the description
of the phases of Alternative 2, page 46. Per CERCLA, a review of the site will be conducted
five years after extraction/treatment operations arc discontinued.
9.3 Estimated Costs for the Selected Remedy
A summary of cost for each of the alternatives was presented in Table 10. A more detailed cost
breakdown for each of the three potential phases of Alternative 2 arc provided in Table 11. These
costs were annualizcd where appropriate (e.g., long-term monitoring costs) and summarized in net
present value (1993) using a five percent annual discount rate.
51
-------
Table 11. OCVZ selected remedy cost summary.'
Cost Elements
Construction
VVE/Monitoring Wells
Field Personnel
Site Improvements
Treatment System/Discharge Monitor
Additional Direct Costs
Project Supervision * Engineering
Contingency (30 %)
^^^^^|Constructton Subtotal
Operations and Maintenance
Technical Support
Operating/Maintenance Labor
Materials tt Equipment
Vapor Sampling
Additional Direct Costs
Project Supervision & Engineering
Contingency (30 %)
^^^^^•O&M Subtotal
^^^^^^^^•^^^^^^^^^^^^^^•^^•^^^^^^^^•^^M^MMM^^^^^^BBMI^BBM^^^^H
Post Closure Monitoring
Well Closure/Demolition
Vapor A Groundwater Monitoring
Project Management
Contingency (30 %)
^^^^^•I'ost Closure Monitorine Subtotal
TOTAL (b)
Vapor
Phase 1
$558.800
- $76,200
$11,025
$583,473
$132,691
$955,532
$695,316
$3,013.037
$75,233
$144,320
$132,735
$1,805,660
$83,919
$1.569,320
$1.143,363
$4.954.569
$7,673
$3,128,250
$625.644
$1,126,171
$4,887,738
$12,860,000
Alternative 2
Vacuum Extraction (WE)
Phase 2 Phase 3
$967.371
$131,337
$21,003
$937,257
$219.740
$1,597,506
$1,162,264
$5,036,479
$211.765
$295.623
$340,475
$4,126,717
$203,022
$3,624,321
$2,640.578
$11,442,502
$11,227
$3,390,684
$747,643
$1.345.763
$5,495,316
$21,970,000
51.337,117
$181,235
$40,291
$1,257,423
$299,603
$2,186,414
$1.590,624
$6,892,706 1
$373,403
$451,363
$608,127
$6.851.732
.5344,740
$6,040.555
$4.4.00.977
$19,070,897
$14,241
$3,943,952
$869,642
$1.565.355
$6,393,189
$32,360,000
(a) All costs repreicBt 1994 dollars «t t 5% discount rate.
(b)Total cost* aave b*«» rooodwi to the •«ar*st $10.000 aid ar« ctnolativ* for Alternative 2.
52
-------
10. STATUTORY DETERMINATIONS
Remedy selection is based on CERCLA, as amended by SARA, and the regulations contained
in the NCP. All remedies must meet the threshold criteria established in the NCP: protection of
human health and the environment and compliance with ARARs. CERCLA also requires that the
remedy use permanent solutions and alternative treatment technologies to the maximum extent
practicable and that the implemented action must be cost-effective. Finally, the statute includes a
preference for remedies that employ treatment that permanently and significantly reduce the volume,
toxicity, or mobility of hazardous wastes as their principal element The following sections discuss
how the remedy meets these statutory requirements.
10.1 Protection of Human Health and the Environment
As described in Section 9, the selected remedy satisfies the criterion of overall protection of
human health and the environment by reducing the level of organic contamination in the vadose zone
beneath and within the immediate vicinity of the RWMC and, consequently, reducing the risk
associated with the future use of groundwater from the SRPA. The remedy will ensure that
cumulative carcinogenic risk levels are maintained within the NCP risk range (1 x 10~* to 1 x 10"6),
and the cumulative hazard index is maintained less than 1.
The selected remedy will extract and treat (Le., destroy) the most significant concentrations of
organic contaminants currently in the vadose zone. The remedy will include long-term groundwater
and soil vapor monitoring to confirm the ability of the vapor extraction system to prevent
unacceptable levels of contaminants from migrating to the SRPA. The agencies will be involved in
reviewing the performance of the remedy as part of potential phase transitions expected to occur
every two years after commencement (see description of Alternative 2 phases on page 46 as well as
the description of remediation goals on page 54). Once remedial action objectives are achieved and
maintained and the remedy is discontinued, the agencies will review the OCVZ after a period of five
years to ensure that human health and the environment are being protected. No unacceptable short
term risks will be associated with this remedy.
10.2 Compliance with ARARs
The selected remedy of Extraction/Treatment by WE will be designed to meet all substantive
requirements of the identified Federal and state ARARs. The ARARs that will be achieved by the
selected alternative follow.
10.2.1 Chemical-Specific ARARs
No chemical-specific ARARs are identified for the selected remedy. Soil-specific regulatory
standards have not been promulgated by EPA or the State of Idaho.
53
-------
10.2.2 Action-Specific ARARs
The action-specific ARARs identified for the selected remedy focus on the management of
materials and waste and the regulation of air emissions that may result from any remediation activities
at OCVZ. Regulations that focus on hazardous contaminants include:
RCRA
IDAPA § 16.01.050.5005 (40 CFR 261.10, 261.20 through 26124), "Idaho Rules,
Regulations, and Standards for Hazardous Waste" identification and characterization.
(Relevant and Appropriate)
If there are residuals that are hazardous, then Idaho's standards for generators of
hazardous waste (IDAPA § 16.01.050.06) will be complied with throughout the
implementation of this alternative.
• 40 CFR 264.600 et seq involving prevention of releases from hazardous waste constituents
in miscellaneous units. The overall intent of this regulation is to provide protection of
human health and the environment (Relevant and Appropriate)
Governing regulations that focus on air quality include:
Clean Air Act
• 40 CFR 61.92, "National Emission Standards for Radionuclide Emission from DOE
Facilities" (Applicable).
• IDAPA § 16.01.0U77, "Ambient Air Quality Standards for Specific Air Pollutants"
(Applicable).
Idaho Toxic Air Pollutants for Non-carcinogenic and Carcinogenic Increments
IDAPA §16.01.015.85 and 16.01.015.86 for any source constructed after May 1, 1994
(Applicable).
Idaho Rules for Control of Fugitive Dust
IDAPA §16.01.01.651 (Applicable).
Idaho Demonstration of Preconstruction Compliance with Toxic Standards
IDAPA §16.01.01.210.10 (Relevant and Appropriate).
54
-------
10.2.3 Location-Specific ARARs
No location-specific ARARs are identified for the selected remedy as there are no known
threatened and endangered species, wetlands, rivers, or floodplains located in the area of remedial
•activities.
10.2.4 To-Be-Considered Guidance
In implementing the selected remedy, the agencies have agreed to consider DOE
Order 5820.2A, "Radioactive Waste Management" as to-be-considered guidance. The guidance is not
legally binding.
DOE Order 5820.2A establishes policy, guidelines, and minimum requirements for radioactive
and mixed waste management. The policy establishes that radioactive and mixed waste generation,
treatment, storage, transportation, and disposal operations comply with all applicable Federal, state
and local requirements. Authorities within DOE who are responsible for policy implementation are
identified.
10.3 Cost Effectiveness
Based on expected performance, the selected remedy has been determined to be cost-effective.
This is evident when considering the cost of Alternative 1, Containment of Vadose Zone Vapors by
Capping, which is estimated to be over three times the estimated costs of the selected remedy, yet
there is a high level of uncertainty associated with the ability of capping to achieve remedial action
objectives. Likewise, there is a high level of uncertainty in estimating the benefits to effectiveness
that Alternative 3, Extraction/Treatment by WE with Vaporization Enhancement, would have over
the selected remedy. Alternative 3 has an estimated cost that is over four times that of the selected
remedy.
10.4 Use of Permanent Solutions and Alternative Treatment
Technologies to the Maximum Extent Practicable
The selected remedy utilizes permanent solutions to the maximum extent practicable for this
site. The NCP prefers a permanent solution whenever possible. Because contamination at OCVZ
is so extensive and the concentrations of contaminants decrease with distance from the SDA, the
selected remedy focuses on the extraction and treatment of only the most concentrated areas of
contamination. Those contaminants remaining in the vadose zone will not pose unacceptable risks
to potential receptors. The selected remedy provides protection of human health and the
environment by preventing unacceptable levels of organic vapors from migrating to the SRPA and
the surface. Based on evaluation of the CERCLA remedial alternative criteria, and in particular the
five balancing criteria, extraction/treatment by WE will provide the best solution in terms of long-
and short-term effectiveness, cost, and implcmcntability.
55
-------
10.5 Preference for Treatment as a Principal Element
Because the OCVZ investigation indicated that no action would lead to unacceptable levels of
contaminants reaching the SRPA and that an attempt to contain the contaminants in the vadose zone
above the aquifer would not provide reasonable assurance that the aquifer would be protected,
extraction and treatment of the vadose zone contaminants was viewed as being the only alternative
that would meet remedial action objectives for OCVZ. Extraction and treatment of OCVZ
contaminants under the selected remedy includes destruction of the organic contaminant with a vapor
treatment system (catalytic oxidation) at the surface. This type of treatment is irreversible because
contaminants are converted to carbon dioxide, water, and HC1 gas, which will be discharged at
acceptable levels to the atmosphere.
11. DOCUMENTATION OF SIGNIFICANT CHANGES
The proposed plan for OCVZ was released for public comment in March 1994. The proposed
plan identified Alternative 2—Extraction/Treatment by WE, as the preferred alternative. The
agencies reviewed all written and verbal comments submitted during the public comment period.
Upon review of these comments and preparation of the ROD, it was determined that no significant
changes to the remedy would be required.
The source term for fate and transport modeling of contaminant migration in the vadose zone
was based on estimates by Kudera (see reference on page 9) of the inventory of organic contaminants
shipped from the Rocky Flats Plant in Colorado to the SDA between 1966 and 1970. Since the
modeling and the risk assessment were conducted, estimates of the amount of organic wastes buried
in the SDA have been revised for the development of the Contaminant Inventory Database for Risk
Assessment (CIDRA). The CIDRA database is contained in A Comprehensive Inventory of
Radiological and Nonradiological Contaminants in Waste Buried in the Subsurface Disposal Area of
the 1NEL RWMC During the Years 1952-1983, EG&G Idaho, Inc., June 1994 (EGG-WM-10903).
According to the CIDRA database, less CG4 and more TCE and TCA were disposed of in the SDA
than originally estimated by Kudera. The revised estimates are not considered to warrant a significant
change to the selected remedy because: (1) the model upon which the risk assessment is based was
calibrated to VOC concentrations measured in the vadose zone in 1992; and (2) the selected remedy,
WE, will extract and treat all of the VOCs considered to be COCs, regardless of the relative
concentrations of the organic contaminants in the vadose zone.
56
-------
Appendix A
Responsiveness Summary
A-l
-------
A-2
-------
Appendix A
Responsiveness Summary
A.1 OVERVIEW
Operable Unit (OU) 7-08 is an OU within Waste Area Group (WAG) 7 of the Radioactive
Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL). The
unit comprises the Organic Contamination in the Vadose Zone (OCVZ), as described in the Record
of Decision (ROD) to which this Responsiveness Summary is attached. A Proposed Plan was
released March 28. 1994. with a public comment period from March 31 to April 30, 1994. The
Proposed Plan recommended a phased approach using Extraction/Treatment by a Vapor Vacuum
Extraction (WE) system. Under the plan, the existing WE system would be augmented with
additional extraction wells, monitoring wells, and vapor treatment equipment. This Responsiveness
Summary recaps and responds to the comments received during the comment period. Generally, the
comments reflected a broad range of views, from strong support for the selected alternative to
opposition challenging the baseline data used by the agencies to select the selected alternative.
A.2 BACKGROUND ON COMMUNITY INVOLVEMENT
To initiate the OCVZ investigation, public scoping meetings were held December 9, 10,11,12,
1991 in Boise, Moscow, Twin Falls, and Idaho Falls, respectively. Approximately 125 people attended
the four meetings. The meetings were designed to involve the public early in the investigation; to
explain the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
process; and to allow representatives from DOE and INEL to discuss the project, answer both written
and verbal questions, and receive ideas and suggestions from the public. The scoping meetings were
announced via a fact sheet conveyed through a "Dear Citizen" letter mailed on November 19, 1991,
to a mailing list of 5,600 individuals in the general public and 11,700 employees of INEL. On
November 20, 1991, the U.S. Department of Energy, Idaho Operations Office (DOE-ID), issued a
news release to more than 40 newspaper, radio, and television media contacts. Both the letter and
release gave notice to the public that OCVZ documents would be available before the beginning of
the comment period in the Administrative Record section of the INEL Information Repositories
located in the INEL Technical Library of Idaho Falls, as well as in city libraries in Idaho Falls,
Pocatcilo, Twin Falls, Boise, and Moscow. Additionally, the letter and release notified the public of
the various ways in which they could participate in the investigations and decision-making process.
Display advertisements announcing the 30-day public comment period on OCVZ appeared
between November 20 and November 27, 1991, in eight major Idaho newspapers: the Post Register
in Idaho Falls, the Idaho Stale Journal in Pocatcilo, the South Idaho Press in Burlcy, the Times News
in Twin Falls, the Idaho Statesman in Boise, the Idaho Press Tribune in Nampa, the Lewiston Morning
Tribune in Lewiston, and the Idahonian in Moscow. Similar display advertisements reminding the
public of the upcoming meetings appeared in each of these newspapers several days preceding each
local meeting to encourage citizens to attend and provide oral or written comments. All three
media—the "Dear Citizen" letter, news release, and display advertisements—gave notice of the four
A-3
-------
public scoping meetings and the beginning of the 30-day comment period on December 4, 1991. Two
radio stations in Idaho Falls repeated announcements from the news release to the public at large.
Personal telephone calls concerning the availability of OCVZ documents and public meetings
were made to key individuals, environmental groups, and organizations by INEL Outreach Office staff
in Pocatcllo, Twin Falls, and Boise. Calls were also made to community leaders in Idaho Falls and
Moscow by INEL Community Relations Program staff in Idaho Falls and Boise.
During the meetings that followed, representatives from DOE-ID and INEL discussed the
project, answered questions, and received public comments. Forms for written comments were
distributed at the meetings and the audience was encouraged to comment on the project The
comments received during the public scoping period were evaluated and considered as part of the
Remedial Investigation/Feasibility Study (RI/FS) process.
Regular reports concerning the status of the OCVZ project were included in the INEL Reporter
and mailed to those who attended the meetings and who were on the mailing list Reports appeared
in the March, May, July, and November 1992 and January, March, and July 1993 issues of the INEL
Reporter.
When the investigation was complete, a Notice of Availability for the OCVZ Proposed Plan was
published between March IS and March 20, 1994, in the Post Register (Idaho Falls), the Idaho State
Journal (Pocatello), the South Idaho Press (Hurley), the Times News (Twin Falls), the Idaho
Statesman (Boise), the Lewiston Morning Tribune (Lewiston), and The Daify News (Moscow). A
second advertisement was placed in the same newspapers several days before each open house or
meeting to remind citizens of the opportunity to attend the meetings and provide oral or written
comments. Radio stations in Idaho Falls, Blackfoot, "Pocatello, Hurley, and Twin Falls ran
advertisements during the three days before the open houses at the Pine Ridge Mall in Pocatello and
the INEL office in Twin Falls.
The Proposed Plan for the remedial action of OCVZ was mailed March 28, 1994, to the
7,000 members of the general public and the 400 INEL employees on the INEL mailing list. Copies
of the Proposed Plan and the entire Administrative Record are available to the public in six regional
INEL information repositories: the INEL Technical Library in Idaho Falls; INEL offices in Idaho
Falls, Pocatcllo, Twin Falls, and Boise; the University of Idaho Library in Moscow; and the Shoshone
Bannock Library in Fort Hall The original documents comprising the Administrative Record are
located at the INEL Technical Library, copies from the originals are present in the five other
repositories.
The public comment period on the Proposed Plan for OCVZ was held from March 31, 1994,
to April 30, 1994. No requests for extensions were received. On April 13, 1994, a teleconference
between the League of Woman Voters of Moscow, the Environmental Defense Institute, DOE-ID,
EPA, and IDHW concerning INEL environmental restoration issues was conducted at the request
of Moscow area residents. The teleconference consisted of an overview of the proposed plan,
questions and answers, and a genera! discussion of OCVZ issues.
Open houses were held on April 12 and April 14, 1994, in Pocatello and Twin Falls,
respectively; representatives from DOE-ID and IDHW attended the events to discuss the project and
A-4
-------
answer questions. Mall display sessions were conducted throughout the day of the meeting at each
location to provide access to information for individuals unable to attend the public meetings. Public
meetings were held April 18, 20, and 21, 1994, in Idaho Falls, Boise, and Moscow, respectively.
Approximately 83 people attended the three meetings. Representatives from DOE-ID, EPA
Region X, and IDHW were present at the public meetings to discuss the project, answer questions,
and receive public comments. Each public meeting was recorded by a court reporter; transcripts of
the meetings have been placed in the Administrative Record.
This Responsiveness Summary has been prepared as part of the ROD. All oral comments, as
given at the public meetings, and all written comments are repeated verbatim in the Administrative
Record for the ROD. Fifteen people submitted written comments on the OCVZ proposal and
12 people gave oral comments at the public meetings. To more fully respond to each issue raised
in the comments, DOE divided the comments received into 91 separate comments. The comments
received were coded to indicate which response in the Responsiveness Summary addresses the
comment It should be noted that the Responsiveness Summary groups similar comments,
summarizes them, and provides a single response. The ROD presents the preferred alternative for
the OCVZ at the RWMC, selected in accordance with CERCLA, as amended by the Superfund
Amendments and Rcauthorization Act (SARA) and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). The decision for this OU is based on
information contained in the Administrative Record.
A.3 SUMMARY OF COMMENTS RECEIVED DURING
PUBLIC COMMENT PERIOD
Comments and questions raised during the public comment period on the OCVZ Proposed Plan
arc summarized below. Several questions were answered during the informal question-and-answer -
period during the public meetings on the Proposed Plan. This Responsiveness Summary does not
attempt to summarize or respond to the issues and concerns raised during that part of the public
meeting. However, the Administrative Record contains complete transcripts of these meetings, which
contain the agencies' responses to these informal questions.
As discussed earlier, the public meetings were divided into an informal question-and-answer
session and a formal public comment session. The meeting format was described in published
announcements and meeting attendees were reminded of the format at the beginning of each
meeting. The informal question-and-answer session was designed to provide immediate responses to
the public's questions and concerns. Comments received during the formal comment portion of each
meeting were responded to by the agencies in this Responsiveness Summary. The public was
requested to provide their formal comments on the Proposed Plan either during the formal comment
session of the meeting or in writing before the close of the public comment period. This
Responsiveness Summary responds to those public comments that were recorded by the court
reporter during the formal comment portion of the public meeting or that were submitted in writing
before the close of the public comment period.
Comments and questions on a variety of subjects not specific to the OCVZ Proposed Plan were
submitted during the public comment period. The agencies take public comments very seriously and
have made every attempt to respond to all comments. Some comments, however, are beyond the
A-5
-------
scope of the OCVZ Proposed Plan (i.e., statements of personal belief, favorable comments about
DOE operations in other places, offers of technical assistance). While these comments are
summarized and grouped at the end of the Responsiveness Summary, the agencies have not
attempted to respond to these out-of-scope comments. However, additional information on these
topics can be obtained from the INEL Public Affairs Office in Idaho Falls; the local INEL offices
in Pocatello, Twin Falls, and Boise; and the Environmental Restoration Information Office in
Moscow. Comments and questions regarding community participation were referred to the INEL
Community Relations Coordinator and will be addressed during updates to the Community Relations
Plan. Formal comments and questions on OCVZ submitted during the public comment period are
answered below.
A.3.1 Public Participation
1. Comment: One commenter expressed serious distrust for the entire public comment process.
The commenter suggested that the three agencies had met in secret and that it is farcical for
the public to think it can change what the agencies have already predetermined. (W15-1)
Response: Comments received from the public during the scoping meetings and on the
Proposed Plan are taken very seriously by the agencies and have shaped the OCVZ project
For example, one commenter suggested using natural venting or barometric pressure as an
alternative method of extracting VOCs from the subsurface, which has the potential to save
taxpayer dollars. The agencies are pursuing this suggestion and are currently discussing the use
of this approach after the completion of Phase I, especially if there are indications that
contaminant concentrations have been reduced to levels that no longer threaten the public
health or environment Through active public participation, the public can and very often does
change or modify the agencies' decision.
2. Comment: One commenter is concerned that this project will be lost in the bureaucratic shuffle
and reminded the agencies of the importance of accurate record-keeping. The commenter also
wanted more information about whether the project data are being kept in computer form and
whether the data is kept in places accessible to the public. (T8-6, T8-8)
Response: All sampling data, reports, and project files are kept on electronic media as well as
paper copies. Reports are available to the public through the Administrative Record and at the
Information Repositories, both of which are accessible to the public during normal business
hours. Additional information can be requested through a FOIA (Freedom of Information Act)
request filed with the U.S. Department of Energy. It is the agencies' policy to place all
information that supports the decision-making processes for the particular operable units in the
Administrative Record.
3. Comment: Several commcntcrs commended the agencies for their efforts to include the public.
Many commcntcrs indicated that they appreciated the opportunity to be involved and asked to
be notified about updated information. (T12-1, Wl-1, Wl-3, W2-2, W9-1, Wll-1, W16-3)
Response: The agencies appreciate the public's efforts to become involved with these cleanup
projects. Everyone who commented will receive a copy of the ROD, which includes this
A-6
-------
Responsiveness Summary. Additionally, commenters will receive information on future INEL
projects.
A.3.2 Risk Assessment
4. Comment: What forces were considered in the model (e.g., gravity, capillary attraction,
atmospheric pressure) and the physical phase of the contaminants (e.g., gaseous, liquid, or
both)? (W8-2)
Response: The forces considered ki the risk assessment model (diffusion of the vapor phase,
advection of the aqueous phase, and dissolution or phase-partitioning) were those believed to
have the most significant impact on the fate and transport of VOCs in the vadose zone. Vapor
advection due to density-gradients or barometric pumping, sorption, degradation, and reactions
were considered but not included because of their estimated lack of importance and (in some
cases) difficulty to implement and verify. During the comprehensive WAG 7 evaluation, these
assumptions will be reevaluatcd. Barometric pumping will be given an especially close scrutiny
because of its potential usefulness as a passive remediation technology. More information about
the forces considered in the risk assessment model can be found in Section 5.3.1.3 of the
remedial investigation (Page 5-31).
5. Comment: One commenter asked whether the agencies had allowed for uncertainty. (W13-1)
Response: The agencies allowed for uncertainty by conducting an uncertainty analysis as part
of the Baseline Risk Assessment (BRA) (See Section 6.1.5 of Volume 1 of the RI report).
Uncertainties in the BRA are due to uncertainties in the risk assessment process in general,
specific uncertainties in characterizing and modeling the site, and uncertainties associated with
accurately describing exposures. The Superfund process of estimating risk does not yield fully
probabilistic risk estimates, but conditional estimates given a considerable number of
assumptions about exposure and toxicity. The uncertainty factors associated with OCVZ, which
include the extent of the vapor plume, source volumes, and moisture contents in the subsurface,
arc described in detail in Table 6-18 on page 6-61 of the RI report.
6. Comment: A commenter asked what correlation exists, if any, between the transport model and
the model previously used for water (Schmalz and Polzer, Soil Science, voL 108, no. 1, 1969).
(W8-1)
Response: It is not known what correlation exists between the transport model and the Schmalz
and Polzer model for water movement. However, the transport model was used to simulate the
xenon gas injection test conducted in 1960 near Test Area North and reported by Schmalz
(1969). The simulation considered vapor diffusion and advection and was successful in
recreating the results of the xenon gas injection test Aqueous advection from natural water
movement was not considered due to the short duration of the test and because Xenon-133 has
very low solubility in water. Aqueous advection was considered in the OCVZ transport model
because of the long time-frame examined and the tendency of the organic compounds to
partition into the water.
A-7
-------
7. Comment: One commcnlcr asked what degree of conservatism was introduced in the risk
analysis: 10, 100, or 10,000? The commcnter further stated the public should not have to
search through pages 6-60 in the RI report for this vital information. (W15-8)
Response: Conservatism is introduced into the modeling and risk analysis at various points,
making it difficult to estimate the total degree of conservatism. Modeling uncertainty is dealt
with by using conservative parameter estimates. The strategy was to use realistic and reasonable
parameter values where possible and conservative parameter estimates where there was little
supporting data. It is estimated that the conservativeness of the modeling is about an order of
magnitude or a factor of 10. Conservatism in the risk analysis is estimated to range from 1 to
2 orders of magnitude. This conservatism comes primarily from uncertainty factors used to
account for variation in the general population, extrapolating data from animals to humans,
derivation of chronic exposure limits from subchronic studies, exposure parameters, and similar
issues. Therefore, the total degree of conservativeness is estimated to range from 2 to 3 orders
of magnitude. However, this is not included in the report because of the complexities and
difficulty in making this estimate.
A.3.3 General Technical Comments
8. Comment: One commenter suggested that the aquifer is comparable to a huge lake without
appreciable movement and any infiltration would simply remain there and decompose. (W5-3)
Response: Unlike a lake, the area beneath the Subsurface Disposal Area at the RWMC
compares more closely with a sponge. Air permeability of the vadose zone plays an important
role in the vapor-phase contaminant migration to the air and groundwater pathways. Regional
horizontal groundwater flow of the Snake River Plain Aquifer is to the south-southwest at rates
of about 1.5 to 6 meters (5 to 20 feet) per day. The RI and baseline risk assessment results
indicated that groundwater contamination due to the migration of the vadose zone organic
contaminants to the aquifer will present the most significant future risk to human health if no
action is taken. The modeling done as part of the RI and the risk assessment predicted that the
contaminant plume would not remain in place, but rather travel several miles downgradient of
the SDA if the vadose zone is not remediated. The selected remedy will be designed to
minimize the migration of contaminants and reduce contaminant concentrations, to levels that
do not pose a significant threat to human health or the environment
9. Comment: One commenter stated that there was no mention of the driving force that would
continue to expand the vapor plume and suggested that the vapors would decrease to zero as
evidenced by the 1960 field experiment. (W15-2)
Response: Lateral migration or expansion of the plume occurs primarily by vapor diffusion.
The 1960 experiment referenced by the commenter involved injecting radioactive xenon gas into
the subsurface at Test Area North. The gas concentrations decreased quickly because a
relatively small amount of gas was injected. The gas also had a short half-life and decayed fairly
rapidly. Thus, the results from the earlier experiment are not readily applicable to the situation
at OCVZ.
A-8
-------
10. Comment: Have any measurable organic contaminants been detected by air sampling at the
Subsurface Disposal Area? (W1S-3)
Response Very little data exist regarding VOC concentrations in ambient air at the RWMC
VOCs were detected at the Pad A Excavation Area and at the Pad A Subsidence Hole (which
arc within the RWMC). Carbon tctrachloride concentrations of 17.0 milligrams per cubic meter
were recorded at the Pad A Excavation Area and 11.0 milligrams per cubic meter were recorded
at the Pad A Subsidence Hole. Grab air samples were collected at the Subsurface Disposal
Area in 1987. These samples were collected above and within wellheads to assess worker
exposure. The resulting data were not sufficient to evaluate long-term risks to human health
either on or off the INEL. The volatile organic* carbon tetrachloride, trichloroethylene,
chloroform, tetrachloroethylcne,l,l,l-trichloroethane, and 1,1,2-trichIoro-trifluoromcthancwere
detected above their respective method quantitation limits at several of the wells. The samples
represented an isolated incident and were not used to establish long-term average
concentrations. Air monitoring around the RWMC, however, has not detected adverse
atmospheric concentrations of VOCs.
11. Comment: One commentcr wanted to know how long DOE-ID has been monitoring the vadose
zone. The commenter asked what changes in the rate of vapor expansion were noted during
the 1993 extraction. (W15-4)
Response: Vadose zone investigations at the RWMC began in 1960 and were conducted by
several organizations, including the U.S. Geological Survey and EG&G Idaho, Inc. Subsurface
monitoring is still being conducted as part of a subsurface investigation program that began in
1985. The investigation, which had focused on subsurface geology and hydrology to assess
radionuclide migration, was expanded to include VOCs in 1987 (Mann and Knobel 1987).
Because vapor phase volatile organic have only been recognized in the Subsurface Disposal
Area vadose zone since 1987, the amount of data available and its distribution in the vadose
media is less than the amount of data related to radionuclide and inorganic compounds.
Treatability studies are conducted to assess the effectiveness of treatment technologies that may
be used at a specific site. The 1993 treatability study conducted at OCVZ evaluated the
hydraulic characteristics of the vadose zone and attempted to determine how to optimize the
WE performance. No attempt was made to evaluate the expansion rate of the vapor plume
during this treatability study and, thus, the agencies do not know whether there has been a
reduction in the rate of vapor expansion. However, based on the quantities of contaminants
extracted and treated during the treatability study, it is logical to conclude that the highest VOC
concentration areas may have been temporarily reduced.
12. Comment: One commentcr wanted to know what consideration had been given to the effect
of "drying out" (removing moisture from) the vadose zone as a result of the flow of large
volumes of air through it For example, will this phenomenon occur, and if so, to what extent,
and will it have a positive or negative influence on VOC fate and transport in the subsurface
environment? (W14-5)
Response: The selected remedy will have the effect of drawing cleaner air through the vadose
zone (from the surrounding uncontaminatcd subsurface) and will induce VOCs to partition or
A-9
-------
separate from water into air. Thus, it is not likely that the selected alternative,
Extraction/Treatment by WE will significantly "dry out" the moisture from the vadose zone.
13. Comment: One commentcr suggested restarting the existing WE system instead of leaving it
idle while the five additional Phase I extraction/monitoring wells are installed. The commenter
argued that approximately 13,832 pounds of VOCs can be removed from below the Subsurface
Disposal Area before Phase I is scheduled to become operational Thus, the commenter
believes that the agencies should "just get on with it." The commenter also asserted that
restarting the existing system would provide a better return on the public's tax dollar investment
(W14-7)
Response: The agencies are not currently considering immediately restarting the existing WE
system because of difficulties associated with the handling and regeneration of contaminant-
saturated carbon adsorption beds used during the earlier extraction process. The related
disposal problems are one of the reasons that catalytic oxidation (CATOX) is being evaluated
as a vapor treatment system. Until the CATOX systems are available, however, the agencies
will not be able to begin extraction and treatment. The Proposed Plan includes the use of the
existing extraction well and WE system used (with CATOX modification) in the Treatability
Study. By spending the time to pre-plan the remedial action, by locating the most appropriate
place for the extraction/monitoring wells .to ensure that VOCs are removed from the most
permeable zone of the subsurface, and by ensuring that the remedial action is conducted in the
safest manner possible, the taxpayers are, in a sense, getting a better return on their dollar.
14. Comment: Two commenters stated that using natural venting or barometric pressure would be
more cost effective than the Extraction/Treatment by WE alternative proposed by the agencies.
(Tl-4, W14-10) Another commenter, however, argued that natural venting would be slower and
would take too many years. (T2-2)
Response: The agencies are currently considering implementing natural venting or a
combination of natural venting and Extraction/Treatment by WE after Phase I, especially if
the results from the Phase I activity demonstrate sufficient reduction in contaminant levels.
Originally, barometric pressure to vent contaminants (barometric pumping) was evaluated but
it was not considered in the conceptual fate and transport model The commenter who stated
that natural or barometric pumping would remove VOCs at a slower rate than the selected
alternative is correct. Therefore, due to uncertainty about the length of time required to reduce
contaminant concentrations to safe levels and the potential for ambient air pollution, the
agencies decided not to more fully explore this option. Additionally, the agencies did not
believe this treatment option would meet the remedial action objective of preventing organic
contaminant migration to the groundwater that would result in exceeding acceptable risk levels
and/or federal and state maximum-contaminant levels. The natural venting or barometric
pressure option may, however, be more fully evaluated during the comprehensive WAG 7
evaluation.
15. Comment: One commenter questioned the agencies' characterization of the rate of movement
by contaminants from the surface to the groundwatcr, stating that too much documentation from
other sources contradicts the characterization. (T10-3)
A-10
-------
Response: The agencies agree with the commcnter that there is uncertainty in predicting
migration rates, especially of volatile organic compounds. Volatile organic compounds arc highly
mobile due to their ability to exist and move in a vapor state. However, a number of field
investigations have been conducted at the RWMC that support the conclusions of the modeling.
These investigations included the collection of geologic, hydrologic, and meteorologic data, and
sampling and analysis of surflcial soil, soil vapor, perched water, and groundwater. The agencies
cannot comment on the general statement concerning contradicting documentation mentioned
by the commenter, however, the agencies believe predictions of the rate at which contaminants
move from the surface to the groundwater are realistic, reasonable, and consistent.
16. Comment: One commenter wants to know whether there is a way to automate the process
(WE) to reduce the labor costs involved with the activity. (T8-2)
Response: The Extraction/Treatment by WE system is automated, which is one reason why
the agencies selected this as the preferred treatment alternative. The system requires minimal
labor hours to operate and maintain. Although monitoring of the system will require additional
labor hours, the contractor's use of computerized gas chromatographs will reduce labor hours.
Wherever possible, new technology and automated systems will be evaluated and used.
17. Comment: One commenter inquired whether there was a way to recover the organic vapor of
the solvents and reuse it elsewhere. (T8-3)
Response: Organic solvents could be recovered and reclaimed from the vadose zone using the
PURIS technology. Unfortunately, no viable use could be identified for the mixture of solvents
that would be recovered.
18. Comment: One commenter wanted more information about the "hazard" that exists with Texaco
Regal oil and whether WE would work in its removal. (W3-4)
Response: Texaco Regal oil is a lightweight machining oil that was used in the late 1960s as
a lathe coolant in the foundry at the Rocky Flats Plant near Golden, Colorado. Texaco Regal
oil is a mixture of five base oils that were either soivent-dewaxed, paraffin oils, or napthenic oils.
During the process, the lathe coolant was contaminated with carbon tetrachloride and other
solvents. The carbon tetrachloride and three other solvents (tctrachlorocthylene,
trichloroethylene, and 1,1,1-trichIoroethane) are the contaminants of concern—not the Texaco
Regal oil Before disposal, the oil was mixed with calcium silicate (an absorbent) to form a
viscous, paste-like, green sludge. The solvents, due to their higher vapor pressure, have
migrated into the vadose zone in a vapor phase. The Texaco Regal oil is not believed to have
migrated from the pits. The purpose of the WE system is to remove the vapor phase solvents
from the vadose zone, not to remove the oils from the pits.
19. Comment: One commenter stated that he had yet to see an entity relation diagram or a
contact's diagram for a data flow diagram. In other words, he states, what are the inputs,
outputs and so forth described? (T8-5)
Response: The agencies are not familiar with an entity relation diagram or the terminology
used by the commenter. The agencies interpret the comment to question the validity and
A-ll
-------
usability of the data used as inputs for the results of the RI/FS and Work Plan. Data Quality
Objectives were established in the Work Plan (Chatwin et al. 1992) and detailed in
Attachment III to the Work Plan. The validation and data usability summary contained in
Section 4.6 of the RI presents an evaluation of the data quality supporting the objectives
prescribed in the Work Plan for the OCVZ RI/FS. Data Quality Objectives are established to
support the overall objective of data collection: to ensure that the information collected for
decision-making at the site is of known and adequate quality and is technically sound, statistically
accurate, and properly documented. Per EPA guidance, Data Quality Objectives are expressed
in quantitative and qualitative terms of precision, accuracy, representativeness, completeness,
and comparability.
A.3.4 General Comments on the Proposed Alternatives
20. Comment: One commenter wanted a more in-depth analysis of the in-situ bioremediation
alternative. This alternative seems to be passed off lightly as being too difficult to use for
subsurface treatment, yet it presents a lower cost alternative. (Wl-2)
Response: A discussion of the bioremediation alternative is contained in the Feasibility Study
(See Section 3.2.4 at Page 3-24). One of the reasons the agencies decided not to pursue a
more in-depth analysis of this alternative is that no bioremediation studies have ever been
conducted in the soil type present at the RWMC (Le., unsaturated, fractured basalt). This lack
of information limits the ability to accurately predict bioremediation performance. To perform
such an analysis would take many years and increase the cost of such a remedial action.
Additionally, it is possible that vinyl chloride may be formed due to incomplete degradation of
TCE. Since vinyl chloride is more toxic than TCE, a thorough evaluation of the potential for
vinyl chloride formation under site-specific conditions would be required. The variable
degradation rates among the organic contaminants of concern caused by site-specific conditions
makes it difficult to predict the effectiveness of this option. Thus, the agencies concluded that
the uncertainties associated with the bioremediation alternative made it less preferable than the
proven effectiveness of Extraction/Treatment by WE.
21. Comment: Several commenters addressed technology transfer, suggesting that technology
developed at environmental restoration sites at the INEL be shared with other DOE sites and
private industry and be published in trade publications. (T8-1, W3-5, W14-9, W14-10, W14-11)
Response: DOE agrees with.the commenters. One of DOE's highest priorities is to promote
United States industrial competitiveness through technology transfer. The science and
technology developed in DOE research programs, laboratories, and non-laboratory facilities
helps form a knowledge base that is one of our country's most valuable national assets. DOE's
technology transfer goals include increasing the level of U.S.-bascd industry participation in
DOE research and development, increasing the level of DOE program and laboratory activity
in transferring technology, and accelerating the process of transferring technology and
knowledge.
Various tools are used to facilitate technology transfer to the private sector. The Environmental
Restoration and Waste Management Technology Integration Program has contractual
mechanisms by which industry could become involved with ER&WM activities. These include
A-12
-------
direct procurement of innovative technologies and research through Program Research and
Development Announcements, Research Opportunity Announcements, and cooperative research
efforts through Cooperative Research and Development Agreements (CRADAs). ER&WM
can also provide assistance to small businesses in areas such as proposal preparation and
technology commercialization and business planning. The ER&WM Technology Integration
Program also operates a toll-free telephone number (1-800-736-3282) to identify potential
matches between private sector representatives (and their technologies) and DOE points of
contact, and disseminates information about DOE's R&D programs and associated business and
research opportunities.
Environmental restoration technology is also transferred to the private sector through the
presentation of papers at environmental remediation and technology conferences held
throughout the country. In the past year, INEL scientists and environmental restoration experts
presented more than 40 papers at such conferences, which discussed environmental remediation
technologies used at the INEL.
22. Comment: Two commenters urged the agencies to move forward as soon as possible with
implementation of the remedial action. (W3-6, W14-7) Another urged the agencies to start
mitigation efforts to head off worse problems in the future. (W4-3)
Response: DOE, with EPA and IDHW concurrence, is accelerating remedial action to the
extent practical Based on the positive comments received in support of Extraction/Treatment
by WE and based on the need to remove organics to reduce the threat to groundwater, the
agencies have decided to begin drilling of extraction and monitoring wells. Five extraction wells
and 10 monitoring wells have been drilled and procurement actions have been initiated to obtain
the extraction and treatment systems.
23. Comment: Two commenters stated that their preferred alternative was "No Action." (W5-1,
W7-4, W15-9) Another commenter questioned why so much activity and cost was associated
with the "No Action" alternative. The commenter further stated that "No Action means no
action" and that monitoring, sampling, and other activities associated with the "No Action"
alternative make the alternative meaningless. (W7-3)
Response: The agencies note these commenters' preferences for the "No Action" alternative.
However, the "No Action" alternative, which is mandated to be considered by CERCLA and the
National Contingency Plan was not considered a viable alternative because the results of the
RI and baseline risk assessment indicated that the contamination of groundwater due to the
migration of the vadose zone organic contaminants to the Snake River Plain Aquifer will
present a significant future risk to human health if no action is taken. Thus, all the alternatives
evaluated had to meet the remedial action objective of preventing organic contaminant
migration to the groundwater in unacceptable concentrations. The "No Action" alternative did
not meet this objective and was not considered further.
The costs associated with the "No Action" alternative are largely associated with a requirement
in the National Contingency Plan to monitor every Supcrfund site at which hazardous
substances will remain after the response action. Groundwater monitoring is necessary to detect
contaminant concentrations in the Snake River Plain Aquifer.
A-13
-------
24. Comment: One commcntcr was concerned that some of the tables and figures used to present
technical data were unreadable. Further, the commcntcr stated that if the computer printouts
were more readable the public would have more confidence in DOE's actions. (T8-4, T8-7)
Response: Tables and figures used in documents associated with OCVZ are generally used to
summarize detailed and complex information. Every attempt is made to make the tables and
figures in the Proposed Plan and the Record of Decision as technically accurate as possible
while providing information that is understandable by members of the general public. In
response to this comment, the ROD was reviewed to identify areas in which the tables and
figures could be made more readable and understandable.
25. Comment: Two commentcrs were concerned that special care be taken with all monitoring and
extraction wells located in and around the Subsurface Disposal Area. The commenters asked
that all wells be property capped and monitored so that they do. not become conduits for
contaminant transport into the aquifer. (T6-1, W14-6).
Response:. The agencies concur with the commenters' concern about wells potentially becoming
conduits for contaminants into deeper regions under the Subsurface Disposal Area. Because
of this concern, each borehole at the Subsurface Disposal Area will be constructed so that it can
be used as either an extraction well or a monitoring welL Extraction wells will be completed
only to the 110-foot interbed to draw vapor from above the interbed where the highest VOC
concentrations have been detected. Boreholes that are drilled through the 110-foot interbed
will be sealed at appropriate intervals to avoid creating a conduit for downward vertical
migration of VOCs and other contaminants. Finally, because the sedimentary interbeds appear
to impede or slow vertical migration of VOCs, boreholes will not be drilled through the 240-foot
interbed. The Snake River Plain Aquifer is located approximately 600 feet below the
Subsurface Disposal Area. Additionally, engineering controls will be taken to ensure that the
extraction wells used in the selected alternative are properly capped, eliminating the possibility
of emissions in excess of regulatory limits.
26. Comment: Two commenters suggested using the OCVZ project as a "research platform" to
develop and test new technologies for subsurface characterization and modeling, vapor vacuum
extraction, and vapor treatment One person asserted that this would directly support DOE's
and EPA's efforts to expand the development of environmental technologies. (W14-8, W15-11)
However, another commenter complimented the agencies for "not studying [the project] to
death." (Tll-1)
Response: Using OCVZ as a developmental research project is being considered.- However,
the agencies all agree that the first priority is to cleanup the site and meet the remedial action
objectives. Although Extraction/Treatment by WE is the preferred option, the contractor will
be working with DOE's Office of Buried Waste and Technology Integration Program to
continually pursue more efficient and cost effective extraction and treatment technologies.
Currently, the INEL has teamed up with DOE's Savannah River Operations Office to conduct
vapor extraction tests. These tests will be conducted at the Savannah River site. However, if
the tests do not interfere with the INEL's ability to meet its cleanup objectives, additional
research and development could be conducted at the INEL on vapor extraction technologies.
A-14
-------
27. Comment: One commcntcr questioned the accuracy of the total mass balance used as the basis
for the risk assessment. The commcntcr argued that the impact of this inaccuracy is significant.
He requested to see some of the documentation on which the agencies based their figures to
assure himself that the numbers are valid. (T10-1) Another commcntcr agreed that the initial
concentrations arc extremely crucial and are hard to grasp. (Tl 1-2, Tl 1-4)
Response The agencies agree with the commentcrs that waste volume and concentrations are
extremely important factors in the risk assessment To ascertain the volume of waste at the site,
three waste characterization investigations were conducted for the VOCs at the Subsurface
Disposal Area. In performing the waste characterization investigations, waste management
personnel at the Rocky Flats Plant were contacted to obtain as much data as possible on
quantities of volatile organic wastes that were shipped to the Subsurface Disposal Area. The
total volume of used oil, carbon tetrachloridc, trichloroethanc, trichloroethylenc, and
pcrchlorocthylene received and the dates of receipt were obtained from the Rocky Flats Plant
Waste Management monthly reports. These monthly reports also provided data on the amount
of lathe coolant received at the Subsurface Disposal Area. Because monthly reports for 1966
and 1969 were not available, quantities of contaminants shipped to RWMC were estimated
based on information contained in the other reports. As a result of these investigations, the
amounts of hazardous materials stored or disposed of at the RWMC were quantified and the
unique waste characteristics attributable to organic material processes were identified. A
detailed discussion of the contaminant inventory is presented in Section 3.2 of the OCVZ Final
Work Plan and in Section 4 of Volume 1 of the RI report. Both of these documents are in the
Administrative Record associated with this remedial action and are available to the public.
The agencies agree that the accuracy of the "total mass balance" is extremely important for
accurate assessment of the potential risk to human health and the environment That is one
reason why DOE went to such measures to quantify the sources of the VOCs in the vadose
zone. DOE admits that the data is not 100 percent accurate because of lack of data prior to
1966 and the missing monthly reports for the years 1966 and 1969. However, the agencies feel
that sufficient data exists to provide meaningful input into the risk assessment and that any
inaccuracies caused by estimating the missing data do not significantly affect the quality of the
results- of the assessment.
28. Comment: One commenter challenged the assumption that institutional controls could be
maintained at the remediation site for one hundred years. The commenter cited changes during
the last one hundred years as examples of how difficult it is to project what will be happening
one hundred years into the future. (T10-2)
Response: As part of the human health evaluation for the OCVZ, it was assumed that DOE
would continue to operate and maintain the RWMC and prevent unrestricted public access to
the RWMC until the year 2092. Institutional controls including restricting land use, controlling
public access, posting signs, constructing fences or other barriers, and monitoring the
environment are employed and will continue to be maintained at the RWMC. DOE has
committed to maintain active institutional controls at ail low-level radioactive waste disposal
facilities for 100 years following closure. (See DOE Order 5820.2A). While the agencies agree
that it is difficult to project what will be happening in 100 years, it is reasonable to assume that
DOE (or its successor) will still be operating and maintaining the RWMC in 100 years.
A-15
-------
29. Comment: One commcntcr was concerned that some of the input data was unknown
(i.e., initial concentrations, time period over which the contaminants arc dumped into the pit,
reactions with other chemicals) and that other input factors were virtually plucked out of the
air (i.e., hydraulic factors, especially porosity and dispcrsrvity). The commcntcr stated that these
inputs are crucial computer inputs which dramatically affect the results; in other words: garbage
in, garbage out (Tll-2, Tll-3)
Response: The agencies do not contend that this modeling is'without any uncertainty. As
noted by the commcntcr, there is a direct relationship between the uncertainty in the model and
the amount of historical data available. The source of the contamination observed in the vadose
zone below the trenches and disposal pits is documented through historical data from the
contaminant inventories (See Response to Comment No. 22). Additional basis for input data
into the fate and transport model were obtained from the Radioactive Waste Management
Information System (RWMIS), previous waste characterization activities, and waste inventories
of the materials disposed at the Subsurface Disposal Area. Parameters for the RWMC vadose
zone VOC transport model included thickness, porosity, saturation, effective air porosity, and
tortuosity factors. These parameters are based on previous studies and on actual data taken
from in and around the RWMC The value for porosity was estimated from results of analyses
conducted on core samples for the surface sediments, interbeds, and basalt flows at the RWMC
down to the 240-foot interbed. Saturation values were estimated using results from analyses
conducted on vesicular basalt samples. Dispersrvity values were based on analysis of
contaminant transport at a nearby INEL facility and checked against ranges reported in relevant
literature. Other assumptions used for the development of the transport model are presented
in Section 53.13 of the RI report. As additional data are collected, valuable information on
rates and direction of contaminant movement will increase the accuracy of the model and
decrease the uncertainty of model predictions because less reliance is placed on estimating past
releases.
30. Comment: One commenter stated that the alternatives for handling contaminants in the vadose
zone under the RWMC should not include Alternatives 0 or 1. The commenter felt that these
alternatives were not acceptable because an earthquake may shift the earth and/or open a direct
path of flow to the Snake River Plain Aquifer. (W6-1) Another commenter, however, asked
that the first alternative (capping) be given additional consideration; particularly in regard to the
order of magnitude of the added cost of the preferred alternative. (W8-3)
Response: The agencies agree that. Alternatives 0 or 1 are less protective than the selected
alternative, although not because of the catastrophic earthquake scenario envisioned by the
commenter. Alternative 0 (the "No Action" alternative) was not chosen because an
unacceptable risk remained to both human health and the environment Alternative 1
(Containment by Capping) also was not chosen for the same reason. Even with a cap in place,
organic contaminants would continue to migrate laterally and vertically in the vadose zone,
primarily in the vapor phase. However, capping would limit the contact of water with organic
contaminants at shallow depths; thus, migration of organic contaminants dissolved in infiltrating
moisture might decrease.
31. Comment: One commenter stated that it is not possible to achieve zero contamination at any
practical cost and that there is no need to do so. The commcntcr further stated that carbon
A-16
-------
tctrachloridc, trichlorocthyicnc, tctrachlorocthylcnc, and 1,1,1-trichlorocthanc contaminants
have been with us for years and haven't been shown to be toxic at low levels. (W16-2)
Response: The agencies agree that it is impossible and unnecessary to eliminate all the organic
contamination from the subsurface. It is also true that the contaminants of concern have been
around for a long time and are not toxic at concentrations below the MCLs.
A.3.5 Commenter Agreed with Selected Alternative
32. Comment: Several commenters indicated their agreement with the preferred alternative
selected by the agencies. The preferred alternative, Extraction/Treatment by WE, was
recognized as presenting the least risk to workers and the public and as being the most cost
effective and protective alternative that prevents organic contaminants from migrating to the
groundwatcr, which would result in groundwater contaminant concentrations exceeding
acceptable risk levels. (TM, Tl-3, T2-1, T2-4, T2-5, T5-1, T7-1, T9-1, W3-1, W4-1, W5-2,
W9-1, W10-1, W12-1. W14-1, W16-1, W16-3)
Response: DOE, EPA, and IDHW agree that Alternative 2, Extraction/Treatment by WE,
is the alternative that best meets the remedial action objectives and the nine evaluation criteria
identified under CERCLA. A long-term groundwater and soil vapor monitoring program will
ensure that this selected remedy will be protective of human health and the environment.
33. Comment: One commenter stated that WE has been definitively shown to be effective at
removing vapor-phase VOCs from the subsurface environment and that it is a fairly mature
remediation technology (fairly high reliability of performance). The commenter further stated
that CATOX is a logical choice for destruction of VOCs that have been removed from the
subsurface. (W14-2)
Response: The agencies agree with the commenter's statement.
A.3.6 Commenter Disagreed with Selected Alternative
34. Comment: One commenter stated that it didn't make sense for agency representatives to justify
spending his tax dollars by claiming to save lives when the agencies didn't know where the lives
are that the agencies claim they're impacting. The commenter continued by stating that he
didn't believe the agencies had done their homework. (T3-1) Another commenter stated that
there was too much concern over highly improbable happenings. (W5-4)
Response: The results of the Human Health Evaluation (HHE) conducted as part of the
Baseline Risk Assessment showed that the organic contamination present in the vadosc zone,
if not addressed by the selected alternative or one of the other alternatives, could migrate to
the Snake River Aquifer and contaminate the groundwatcr. Future groundwater users would
then be at risk. The agencies believe that implementation of the WE Extraction/Treatment
system will remove the risk posed to future groundwater users.
A-17
-------
The agencies arc not asserting that the results of the HHE can predict with 100 percent
accuracy the exact risk to the future groundwatcr users. The agencies do believe, however, that
sufficient information has been collected and evaluated to make reasonable estimates on the
human health risks posed by the organic contamination in the vadose zone.
While the probability of a future resident using groundwater pumped from the vicinity of the
RWMC may seem improbable to some, CERCLA and the NCP require the agencies to assess
this risk as part of the HHE. It is true that the estimates of carcinogenic and noncarcinogenic
risks are based on conservative assumptions associated with both the fate and transport
modeling and the risk assessment The conservative assumptions used in the fate and transport
modeling and the risk assessment compensate for the uncertainty inherent in assessing the risks
to human health and the environment
A.3.7 Other Comments on the Selected Alternative
35. Comment: One commenter noted that there are commercially available, trailer-mounted units
that should be more cost effective when compared with in-house design and construction.
(W14-3)
Response: The agencies plan to employ commercially available WE systems as part of the
selected alternative at this site. Several manufacturers supply modular WE/CATOX units
equipped with a fan, a catalytic oxidation chamber, instrumentation, an exhaust stack, and
housing. These units are compact, require very little operator interface, and are cost effective
for large-scale treatment of vapor-phase contaminants, such as those present in the vadose zone
at the RWMC Any modifications to these units (in-house design) will involve the adaptation
of these pre-fabricated systems to meet the site-specific requirements at the RWMC.
36. Comment: One commenter stated that contrary to what was presented in the Proposed Plan,
wastes would be generated under Alternative 2 (Le^ catalytic waste, hydrochloric acid and/or
chloride salt and paniculate matter collected by the HEPA filters). (W14-4)
Response: The commenter is correct in stating that wastes or residues will be produced by the
vapor treatment system. However, under Alternative 2 with Extraction/Treatment by WE as
the selected treatment alternative, it is expected that residual treatment wastes would not be
generated in quantities above regulatory limits of concern. Because such low concentrations of
VOCs are associated with the vadose zone at the RWMC catalysts are not expected to be
changed frequently. At sites that have used catalytic oxidation for similar types of
contamination, catalysts must be changed every two years; however, the catalysts can be disposed
of as solid (not hazardous) waste. Because the results of the remedial investigation indicated
no radionuclide contamination present at OCVZ, no high efficiency paniculate air (HEPA)
filters arc required as pan of the extraction and treatment system. Although the commenter
is correct in stating that hydrochloric acid would be formed during catalytic oxidation, the
quantities generated arc below regulatory limits of concern. This small amount of waste may
require further treatment through neutralization. If necessary, caustic scrubbing systems could
be installed at each treatment location. The scrubbing system would produce neutral pH, low-
concentration salt-water solutions that can be discharged to a publicly owned treatment works
or to surface drainage.
A-18
-------
37. Comment: One commcnter stated that Extraction/Treatment by WE should be initiated in the
highest concentration areas and that limits should be placed on WE operations. The
commcnter believed that the agencies should not attempt to remove contaminants to minuscule
levels only detectable by sophisticated instrumentation. (W3-2, W3-3)
Response: The agencies agree with the commenter. The selected alternative will be centered
in those areas with the highest concentrations and will remove and destroy VOCs to the
targeted cleanup goal of 30-200 parts per million volume for carbon tetrachloride. The
agencies believe that such a cleanup goal will meet the remedial action objective of preventing.
organic contaminant migration to the groundwater in levels that pose a threat to human health
or the environment
38. Comment: One commcnter suggested incorporating some flexibility into the plan as it will
almost certainly have to be modified at least slightly as the activity proceeds. (W13-2)
Response: The selected alternative, Extraction/Treatment by WE, allows for three possible
phases of clean-up activity over a 6-year period. One of the primary reasons the agencies chose
a phased approach was to allow for the uncertainties involved with this project The
complexities of the subsurface environment and uncertainty associated with the modeling make
it difficult to predict how many wells will eventually be needed. Thus, the agencies have
incorporated sufficient flexibility to add more extraction wells if, after Phase 1, contaminants
levels do not appear to be decreasing in sufficient amounts. Conversely, the selected alternative
also allows for a lower-keyed approach (i.e,, natural venting) if, after Phase 1, contaminant
levels appear to have been decreased to safe levels.
39. Comment: One commenter stated that there was no indication of the amount or percentage
of VOCs expected to be removed or even a goal for the activity. The commenter asserted that
"believing you will remove the most significant concentration" is inadequate. (W15-7)
Response: The targeted cleanup goal from carbon tetrachloride ranges from 30 to 200 parts
per million volume depending on the depth within the vadose zone. Other vadose zone
contaminants have similar goals. The selected alternative will be designed so that the remedial
system meets these goals. The goals have been established so that vadose zone contaminant
concentrations will result in groundwater contaminant concentrations that meet the remedial
action objective.
A treatabflity study was performed as part of the clean-up activity to assess the effectiveness of
treatment technologies that may be used as remedial alternatives on site waste. The treatability
at OCVZ demonstrated that Extraction/Treatment by WE can reduce vadose zone organic
contaminant concentrations. Based on the results from the trcatabiiity study, the agencies
believe an array of vapor extraction wells at selected locations in the RWMC will effectively
reduce contaminant concentrations in the vadose zone to acceptable levels.
40. Comment: One commenter stated that in previous studies, suggestions had been made to
introduce cold air down the wells to freeze the moisture in the wells to prevent downward
migration of water carrying contaminants. (Tl-2)
A-19
-------
Response: Introducing cold air during the winter to freeze moisture and possibly prevent or
slow downward migration of dissolved contaminants was not examined in the feasibility study
because it is an unproven and undcmonstratcd technology. If it were possible to prevent
downward migration of water, VOC contamination reaching the aquifer would be reduced.
However, the contaminants would still reach the aquifer as vapors.
A.3.8 Funding, Budgeting, and Scheduling
41. Comment: Several commcnters were concerned about the cost of the preferred alternative.
Most felt that the agencies were spending too much money. One .commenter stated that no
business would recommend spending S13-67 million to remove a marginal threat to public
health and that he would rather see his taxes spent on saving lives (e.g.. Boron Neutron Capture
Therapy). However, two people stated that the agencies should err on the side of safety and
spend whatever is needed to protect the aquifer and public health. (T4-1, T7-2, W2-1, W15-S,
W15-12)
Response: In these tight budgetary times, all the agencies share the commenters* concerns
regarding the amount of money spent on remedial actions. The cost estimate of approximately
$12-32 million associated with the selected alternative includes direct and indirect costs
associated with construction and operations and maintenance, and post-closure costs for long-
term monitoring. Contingency costs were included for each of the three primary cost elements
(construction, operations and maintenance, and annual post-closure monitoring). Contingency
costs are generally reduced as details of the design for a particular remedial action are refined.
The cost estimates provided in the Proposed Plan are rough estimates (Le., -30% to +50%) and
are given for comparison purposes only. Cost estimates for sampling and monitoring activities
will be provided in greater detail in the Remedial Design phase, which follows the ROD. Costs
may appear high because overhead rates with the management and operations contractors and
general and administrative rates are all factored into the ultimate cost estimate. The
administrative costs associated with federal cleanup sites tend to be higher than those associated
with private industry sites.
With an ever-shrinking federal budget, a number of measures are being taken to better manage
the direct and indirect costs associated with DOE remedial actions. [At the INEL, a 5-year
consolidated contract was recently awarded that is designed, in part, to reduce the levels of
bureaucracy at the facility.] One cost-saving measure specific to OCVZ was selecting a phased
approach to the action allowing agency decision-makers the flexibility to reduce the scope of
the project if, following an evaluation of the implemented remedy (approximately two years
after implementation), the agencies conclude that indications from monitoring shows that the
vadose zone contamination is sufficiently reduced to prevent federal and state maximum
contaminant levels from being exceeded in the aquifer. If that conclusion is reached, the
agencies may decide to shut down the system or shift to a passive system.
42, Comment: One commenter noted that the agencies must obtain funding every budget period
to allocate to this project. The commenter further noted that Alternative 2 has a good chance
of getting funded because it can be demonstrated to work. (T2-3, T2-4).
A-20
-------
Response: DOE has allocated and forecasted funding for the OCVZ project and fully expects
funding to be available for the duration of this project. However, as with all government
moneys, these funds are subject to congressional appropriations and oversight. This fact may
potentially influence the funding for OCVZ each fiscal year.
43. Comment: One commentcr stated that inadequate justification has been made to accelerate this
applied experiment over a 2-ycar period. (W15-10)
Response: Extraction/Treatment by WE is a proven and well-established remediation
technology to recover vapor phase organic contaminants from subsurface soils. Based on the
results of the treatability study, which proved that Extraction/Treatment by WE would be
effective for the removal of organic contamination in the vadose zone and on the generally
positive public support for the project, the agencies decided to implement Alternative 2 as the
selected alternative. After evaluating the results from Phase I (lasting approximately two years)
a decision will be made as to the level of activity necessary to ensure protection of human
health and the environment If, after Phase L, the remedial action objective has been met
(reduction of contaminant levels so that organic contaminant migration to the groundwater will
not result in groundwater contaminant concentrations exceeding acceptable risk levels and/or
federal and state maximum contaminant levels), then a decision will be made about the level of
remedial activity needed during Phase II (Le., reduce/expand the number of extraction wells, use
natural venting, or use a combination of natural venting and Extraction/Treatment by WE).
A.3.9 Comments Deemed Beyond the Scope of the OCVZ ROD
Comments and questions on a variety of subjects not specific to OCVZ were received during
the public comment period. Those subjects included editorial comments concerning language in the
Proposed Plan, statements of general distrust for the DOE actions, offers to provide technical
assistance on the project, statements concerning past work at the INEL, personal preferences on how
taxpayer money should be spent These out-of-scope comments are not responded to in this
Responsiveness Summary. Additional information on these unrelated subjects can be obtained from
the INEL Public Affairs Office in Idaho Falls or at the local INEL offices in Pocatello, Twin Falls,
and Boise.
A-21
-------
Appendix B
Public Comment/Response List Index
B-l
-------
B-2
-------
Appendix B
Public Comment/Response List Index
The Public Comment/Response List Index was created to enable commenters and other
interested persons to locate the agencies' responses to individual public comments. All oral
comments, as given at the public meetings, and all written comments, as submitted, were typed into
the attached index. Each comment was then subdivided and assigned a comment code. The codes
indicate whether the comment was either written (W code) or taken from the public meeting
transcript (T code). The agencies tried to divide comments according to specific concerns, issues or
points made by the commentcr.
Sixteen people submitted written comments (comments W1-W16) and 12 others gave oral
comments at the public meetings (comments T1-T12). Copies of oral and written comments
annotated with their respective comment codes are located in the Administrative Record.
To locate a response to a specific individual's comments, look up the last name of the individual,
identify the specific comment you are looking for, then turn to the comment number or page
indicated in the Responsiveness Summary.
If, after reviewing the annotated comments in the administrative record, a reader wishes to
locate a response to a specific comment, he/she can use the comment code to locate a response as
well. The reader should identify the comment code in the index, look up the comment and page
number of the response then turn to that page of the Responsiveness Summary.
Comments involving multiple issues were further subdivided and answers may appear in more
than one place in the Responsiveness Summary. This was done for only five of the 95 comments.
B-3
-------
PUBLIC COMMENTS .RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
NC
Tl-1
Tl-2
Tl-3
TM
T2-1
T2-2
Rcspome
Number
NA
32
40
32
14
32
14
Jack
Barradough
Jack
Banadougb
Jack
Barradough
Jack
Barradougb
Jack
Barradough
CE.
White, Jr.
CE
White, Jr.
This is an interesting project to me because I first
started studying the burial ground about 30 years
ago at the RWMC And along the studies, we '
defined the geology of which they're still using and
had a feeling for what to do with this waste that's
been placed there.
In 1980, we looked for organic contaminants. We
looked in the pans per million range and couldn't
find them. In 1987, they were detected in the pans
per billion range.
The vapor vacuum extraction is a very exciting
project, and it's one that Dr. Dave AUman— about
it, but we had a little bit different concept where
we'd use the natural breathing and venting by using
wells.as a short circuit and using the changes in
barometric pressure as the pump and then filter the
air.
I think the system that they've developed now is
superior to our original concept.
[W]c wanted to introduce cold air during the winter
to freeze what moisture was in there to prevent
downward migration of water carrying
contaminants.
And I think the analysis is good and I think the
modeling studies are good. And I support the
preferred alternative, and I think it's probably the
most cost-effective and the most dynamic.
I would suggest that you do seriously consider
natural— using the changes in barometric pressure
as more cost effective, maybe not now, but in the
future.
I think the alternative that Jack is talking about is
going to be the one.
I just— I just don't think that wc-with the
barometric pressure, it's going to take too many
years to do it. I think it's going to be a slower
process to do it. Jack. I don't know. You may not
agree with me, but I think it's going to be a lot
slower.
fosc Number
Out-of-Scopc/Not Responded To
A- 17
A-20
A-17
A-10
A-17
A-10
B-4
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
T2-3
T2-4
J2-5
T3-1
T4-1
T5-1
T6-1
T7-1
T7-2
Response
Number
42
32,42
32
34
41
32
25
32
41
fYmmpntcr
CE.
White, Jr.
CE
White, Jr.
CE.
White, Jr.
Bob
Delveal
Nicole
LeFavour
John
Anderson
Fritz
Bjomsen
Walt
Hamson
Walt
Hamson
f^iimmuil
And we will have to— the government will have to
come up with money every period, every budget
period, to allocate to this.
[I]f we choose the No. 2 one, which is the pump, I
think we've got a good chance of getting it funded
because I think it will work and 1 think we can
prove it will work.
I agree also that that would be the alternative to
accept.
It doesn't— it doesn't make sense to me for you
folks to stand up here and justify spending my tax
dollars doing this for the purpose of saving lives
when you don't know where the lives are that
you're impacting. I don't think you've done your
homework.
I'm concerned that possibly the money being spent
is perhaps— I guess I should phrase this better.
Perhaps you're being cautious with the money
you're spending, and I guess I just want to make
sure that there isn't the possibility that you need to
do perhaps the $59 million treatment. I hoped that
you will err on the side of the cautious. And I
think it looks good.
I really fed that your vapor extraction is a correct
method. I'm very familiar with vapor extraction
and this is probably as cheap-you're going to get
the best bang for your dollar right there.
I guess my concern would be simply that during the
process, ad care be taken that the monitoring wells
and the vapor vacuum extraction well be properly
capped and monitored to prevent increased
migration both of the solvents and potentially other
RWMC that might find an easy pathway to the
aquifer through the wells that are being dug.
It looks to me like you've done a pretty thorough
job.
Personally, it seems to me that the Preferred
Alternative looks pretty reasonable, as long as you
hold kind of close to that 12 instead of the 32.
Page Number
A-22
A- 17, A-22
A-17
A-18
A-21
A-17
A- 14
A-17
A-21
B-5
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
T8-1
T8-2
T8-3
T8-4
T8-5
Rcspome
Number
21
16
17
24
19
Walter
Becway
Walter
Bctway
Walter
Bctway
Walter
Betway
Walter
Bctway
Cbmmeat
I mentioned earlier the concern for technology
transfer, and I think that still should be a very high
priority and I don't think it's roily being acldrewed
We're also not dealing with costs in a more detailed
breakdown. If you're going to run the program
two years and say it goes to three, can we work at
automating this to reduce the labor cost and to let
it do its thing even if it takes five or ten years
jwithout high labor costs?
We need to look at can we recover this organic
for something else? The reason being is that you
may not have a lot here, but there is a lot in other
dumps elsewhere throughout the world.
And this, reinventing the wheel does bother me a
bit. I still think that, like you say, I don't trust
computers, and just because the computer says this,
I can also program computers to make any answer
I want. And this is where I need— feel, I should
say, that software documentations should be
readable and these programs should be described
as what they do much more in the public domain.
They're right now, as Car as I know, almost no
indication of this in the INEL Repository, or at
least references to such. Pan of the data
processing which is not unique to INEL, it's
throughout the whole computer industry.
We're taking too much in faith that the computer
model is accurate or even meaningful I don't even
know what the variables are that go into it or come
out of it All I can do is guess. I think that's
unfair and also make is unuseful for other projects
in the future.
I have yet to see an entity relation diagram, that's
bow to date and relate to each other. A contact's
diagram for a data flow diagram, IVe yet to see one
of those anywhere mentioned. In other words,
what are the inputs, outputs, and so forth
described.
Page Number
A-13
A-ll
A-ll
A-14
A-12
B-6
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Rrapowe
Number
Page Number
T8-6
Walter
Bctway
So I'm looking at this equipment, whatever you're
doing on tots, to be useful and transferable and do
a good job here, rather than do a, shall we say, a
least effort and then hopefully forgotten. You
known, we did our project, we cleaned it up; but
it's all lost like many of the other files and piles of
reports and is unusable by anyone else. So record-
keeping is still a critical area.
A-6
T8-7
24
Walter
Bctway
And I'd like to see those computer printouts,
definitely as I mentioned before, be made much
more readable. It's a biting that's not professional
in my opinion. It's much—I think hackers even can
do better jobs on some of these printouts. And as
you do such things, it will give the public confidence
by making these things more readable rather than,
shall we say, questionable because the AEC—or
Atomic Energy Commission or the DOE now—has
in the past, hid so much in secrecy or in records
that are questionable in value.
A-14
Walter
Bctway
And I'd like to see where its referenced to where
the data records are being kept in your Information
Repository in computer form. Do you even have
one, or is this kept in somebody's desk, third
drawer down next to the garbage can? These are
the concerns I would like to see INEL succeed and
has to be dealt—these problems have to be dealt
with.
A-6
T9-1
32
Kent
Man in
I support any effort in site remediation at any
facility in the United States. And I'm very please
to see that Idaho has taken the time and effort,
because it's very, very difficult to do all this. And I
commend aD of your on your effort to take on this
monumental task. So, I support you one hundred
percent.
A-17
T10-1
27
Chuck
Droscious
I'm not convinced that the total mass volumes that
you aD are using as your base for what was
disclosed of there is accurate. And in terms of the
ramifications, if that number is not correct and how
that would impact your risk ranges and whatnot is
significant. And I .would like to sec some
documentation on what you base those figures on,
you known, to assure me that you're working from
numbers that arc pretty'solid.
A-15
B-7
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
T10-2
T10-3
TIM
T1I-2
Rcsponae
Number
28
15
26
27.29
fjuiumjiUJ
Chuck
Brosckxts
Chuck
Brosckxis
Neil
Fanner
NeU
Fanner
fjuimujit
In icnns of maintaining institutional control for 100
yean, I think it's important to stop and think about
what was going on in 1894. This was decades
before even the automobile. This was before paved
highways and this was during the time when people
road the trains around, a lot of them were wood
Tired. So, in terms of projecting, you known,
another hundred years out there and making
assumptions that there's going to be something that
we call the United States of America is being very
presumptuous. And I think we need to be thinking
projections out there.
And again, I do not have a lot of faith in your
from the surface to the groundwater, because I've
had too much documentation, other geologists.
hydrotogists, and in and out of Department of
Energy, Atomic Energy Commission, Energy
Resource and Development Agency. You know, it
docsnt— you know there's too much challenge in
I see a few positive aspects and a few negative
aspects. One positive comment that I'd like to
make it towards people working on this problem,
that at least we're coming to a conclusion for a
remedial effort that is— at least we aren't studying it
to death as we are with the salmon issue.
Some of the negative parts of the presentation is of
course some of the data given by computer
programs as mentioned. I just go through with an
povignrncnt basically doing the exact same thing
with a different program. And it is true, initial
concentrations are extremely crucial, over what time
period they are dumped into a pit, and the
reactions with other chemicals. So this— end a lot
of this is completely unknown.
Page Number
A- 16
A-ll
A-15
A-15, A-16
B-8
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Til -3
Tll-4
T12-1
Wl-1
Wl-2
Wl-3
Response
Number
29
27
3
3
20
3
Cbmnxnter
Neil
Farmer
Neil
Farmer
Joe
Lance
Walt
Ilampson
Wall
Hampson
Walt
Hampson
f^i uiLimul
And that's not even to mention the hydrotogic
factors of toe aquifer, namely effective porosity,
spurtivity,, a good many others, that most, even well
experienced and seasoned hydrogeotogists most of
the lime have to virtually pluck out of the air
because there is no hard data for that. And those
are crucial inputs into the computer programs
which will dramatically affect program, garbage in
and garbage out.
What I'm trying to say is the input data is in
essence so bard to get a firm grasp on the— it's very
difficult to have much reliance on the output of the
computer program. But that's not to say that there
are completely inadequate. They're only as good as
the input in, and that's personal experience and
from conversations with seasoned hydrogeologists, I
suppose. namely on the University (acuity.
I'd like to thank you for the opportunity at least to
hear more about what the problem is. Having
worked the last 20 yean or more in the Hagcrman
Valley with fisheries' people and irrigators and
agriculturists, I understand the importance of this
aquifer. I guess my only comment would be I
appreciate the opportunity to hear it, and the
opportunity to respond. I wish I'd knew more bout
it such as many of the people here, but I have
learned. And I would like to apologize for the
mistakes that my generation made by drilling holes
into the aquifer, and maybe through some of this
cleanup, this won't happen, but we at least left it to
our kids to dean up. I appreciate the opportunity
to be here.
Excellent communication— [I] have seldom seen
more accurate and thorough technical composition
in a general publication.
[I] would like to see more in-depth analysis of the
In Situ Bioremediation Alternative. It seems to
have been passed off a little lightly as too difficult
for this subsurface. However if not too difficult— it
would certainly be a much lower cost alternative.
Thanks for this opportunity to comment and good
luck!
Page Number
A-16
A- 15
A-6
A-6
A-12
A-6
B-9
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
CCTJT
W2-1
W2-2
W3-1
W3-2
W3-3
W3-»
W3-5
W3-6
W4-1
W4-2
W4-3
W5-1
W5-2
W5-3
W5-4
Response
Number
41
3
32
37
37
18
21
22
32
NC
22
23
32
8
34
Phyllis
Jones
Phyllis
Jones
Rodger F.
Colgan
Rodger F.
Colgan
Rodger F.
Colgan
Rodger F.
Colgan
Rodger F.
Colgan
Rodger F.
Colgan
Andy
HokJerreed
Andy
HoklcTTccd
Andy
Holdcrreed
Warren
Barry
Warren
Barry
Warren
Barry
Warren
Barry
fTlUIIUlLEJll
We need to dean up the problems of the water
regardless of cost and ASAP as a federal project
and maybe helped by the state.
Please keep us updated as to future information.
Thanks.
I support your recommended Alternative 2.
There should be limits for effective WE operation,
not to remove contaminants to levels of detection
for sophisticated instrumentation.
Activity should be initiated in the highest
concentration areas.
I am not aware of what 'hazard* exists in Texaco
Regal OH and if WE would work in its removal.
The technology for WE should be common,
simple, reasonably cost effective, and shared in
trade publications such as Environmental Protection
and TJf^J., etc.
The implementation should begin as soon as
possible.
The outlined plans would appear to be reasonable.
Plans allow for more well drilling and testing to
determine the extent of the remediation.
I think we must get on with efforts to mitigate the
waste problems to head off worse problems ahead.
[If we were voting,] I would favor Alternative 0 and
simply monitor the material at a great saving in cost
to all
My second choice would be Alternative 2, WE
Phase L This should satisfy all rttoonoble
objections and provide an acceptable solution.
My understanding the aquifer is comparable 10 a
huge lake without appreciable movement. Any
infiltration would simply remain there and
decompose.
Too much concern over highly improbable
happenings.
Page Number
A-21
A-6
A-17
A-19
A- 19
A-ll
A- 13
A-13
A-17
Out-of-Scope/Not Responded To
A-13
A-13
A-17
A-8
A- 18
B-10
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
W6-1
W7-1
W7-2
W7-3
W7-4
W8-1
W8-2
W8-3
NC
W9-1
NC
Rcspome
Number
30
NC
NC
23
23
6
4
.30
NC
3.32
NC
Willard
Adams
R. Ham
Hamilton
R.Ham
Hamilton
R. Ham
-Hamilton
R. Ham
Hamilton
Bruce L.
Schmalz
Bruce L.
Schmalz
Bruce l_
Schmalz
CE.
White, Jr.
CE.
White. Jr.
David H.
Ncdrud
f^lLJILJILJJll
Alternatives for handling contaminants in the .
Vadose Zone under RWMC should not include
Alternative 0 or 1. They do not cut it if one was to
consider an earthquake that may shift the earth
and/or open a direct path of flow to the Snake
River Plain Aquifer.
The last sentence of "Alternative 0: No An ion'
should be the last sentence of Remedial Action
Objectives.
Move the 4.1 million from page 11 to.page 10.
*No Action* means to do nothing in good English.
After afl your blather— leave everything be:
Monitor once each 10 years with improved
technology.
What correlation exists, if any, between the
transport model and that previously used for water
(Schmalz and Potzer, Soil Science. vot, 108, no. 1,
1969)?
What forces were considered in the model (e.g.,
gravity, capillary attraction, atmospheric pressure,
etc) and the physical phase of the contaminants
(e.g, gaseous or liquid or both)?
It is this commentator's intuitive opinion that the
first alternative be given additional consideration,
particularly in regard to the order of magnitude of
the added cost of the preferred Alternative 2.
I have read all of the data available on your
proposed method of attraction have had some one-
on-one discussions with Reuel Smith (among
others) and ...
[I]t is my feeling that you have a workable and safe
remediation procedure. Thanks for the opportunity
to comment.
In December of 1992, our company started a
Vapor Extraction project for a Nevada engineering
firm. The project involved a leaking UST with
unleaded gasoline. From our air and water well
monitoring, we have seen dramatic decreases in
contamination levels in soils.
Page Number
A- 17
Out-of-Scopc/Not Responded To
Out-of-Scope/Not Responded To
A- 14
A-13
A-7
A-7
A-17
Out-of-Scopc/Not Responded To
A-6, A-17
Out-of-Scopc/Not Responded To
B-ll
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
WHM
NC
Wll-1
W12-1
W13-1
W13-2
W14-1
W14-2
W14-3
T.nMnjT-11-a^
Number
32
NC
3
32
5
38
32
33
35
David H.
Ncdrud
David H.
Nedntd
Stan
Sorensen
Robert
Gates
Allen
Merritt
Allen
Merritt
Robert M.
Lugar
Robert M.
Lugar
RobenM.
Lugar
Cbmmcrn
No doubt in our minds that Vapor Extraction does
work, is cost effective, and should be a viable
option for some soil problems at the INEL.
If we can be of any assistance, call our office
anytime. (208) 232-2034 Idaho is our home.
Please keep cleaning up the site! Thank you
DOE/EPA.
No comments at this time, but would like to
receive a copy of the Record of Decision and
Responsiveness Summary.
Your efforts have convinced me that you are doing
the right thing to protect the people and the
environment. Keep up the good work.
Have you allowed for uncertainty?
Incorporate some flexibility as this plan will almost
certainly have to be modified at least slightly as the
effort profffriv
In general, I agree with the preferred remedial
action alternative presented in this proposed plan.
Vapor vacuum extraction has been definitively
shown to be effective at removing vapor-phase
VOCs from the subsurface environment beneath
the RWMC and is a fairly mature remediation
technology (fairly high reliability of performance).
Catalytic oxidation is a logical choice for destruction
of the VOCs once removed from the subsurface . .
rrjhere are presently commercially available
trailer-mounted units which should be the most
cost effective option (versus in-house design and
construction).
Page Number
A-17
Out-of-Scope/Noi Responded To
A-6
A-17
A-7
A-20
A-17
A-18
A- 19
B-12
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
W14-*
W14-5
W14-6
Response
Number
36
12
25
Robert M.
Lugar
Robcn M.
Lugar
RobenM.
Lugar
f\MIIIILI"»l
On page 12, it states that 'it is expected that no
residual treatment wastes would be generated
under Alternative 2. . . ." Keep in mind that
eventually the catalyst will require either
replacement or regeneration, and the associated
costs. In addition, under catalytic oxidation, you
will likely end up with a relatively small amount of
hydrochloric acid (HCL) and/or a chloride salt,
depending on the particular catalytic process used.
There may also be small amounts of paniculate
matter collected by cyclone separator and/or HEPA
filters upstream of VOC treatment component.
Has any consideration been given to the effect of
'drying out* (removing moisture) of the vadose
zone as a result of the How of large volumes of air
through it. For example, will this phenomenon
occur, and if so, to what extent, and will it have a
positive or negative influence on VOC fate and
transport in the subsurface environment? This
does not effect the basic selection of the preferred
alternative; however, it should be considered for
future phase implementation and modeling.
I suggest that throughout all the phases, the
number of extraction and monitoring wells be
minimized to the extent possible. Although present
day well construction techniques should protect the
subsurface from inadvertently acting as conduits for
contaminant transport to the deeper regions, any
penetrations in the SDA are potential conduits.
Page Number
A- 19
A-IO
A-14
B-13
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Ropome
Number
Page Number
W14-7
13,22
Robert M.
Lugar
I suggest the agencies (DOE, IDHW. and EPA)
consider restarting the existing WE system at
RWMC as soon as possible instead of leaving it idle
until tne additional five Phase I
extraction/monitoring wells are installed and WE
systems for these wells are operational. At an
estimated VOC extraction rate (based on the
treatabiliry study) of 1.754 pounds of VOCs/hour,
90% system availability, and a Phase I startup date
of April 1995. approximately 13,832 pounds of
VOCs can be removed from the SDA subsurface
BEFORE the Phase I alternative is initiated if the
existing system is restarted! The remedial objective
is to remove subsurface VOCs to below cleanup
goals — and we presently do not have a reliable
prediction of bow long this will take (from page 17
of the Proposed Plan), so why not get on with it as
soon as possible rather than wait for a whole new
set of paperwork, design reviews, safety analysis and
reviews, etc. for the Phase I systems?
The existing WE system has proven itself to be
safe and effective; aO the necessary operating
procedures, safety reviews, and monitoring
procedures are in place, and trained personnel are
available to operate the system. The disposal of
the spent carbon adsorbers used on this system
should not be an issue, since precedent has been
set by the recent DOE-HO approval of off-site
disposal (at a licensed disposal facility) of spent
adsorbers generated during the trcatability study.
Although we know now that carbon adsorption is
not necessarily the optimum technology to treat the
extracted VOC vapors from the RWMC, it is a
widely accepted and utilized VOC vapor treatment
method, and perfectly suitable until the Phase I
wcUs/syslcms are operational
A tremendous amount of money has been invested
in this existing system (especially if one includes the
1989/1990 tests and 1993 treatability tests), and we
have only recovered an estimated 4,473 pounds of
VOCs to date with it! Why not let it provide a
better return on our tax dollar investment?
A-10, A-13
B-14
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Response
Number
Page Number
26
Robert M.
Lugar
On page 17 it is stated that "the complexities of the
subsurface environment and uncertainty associated
with the modeling, make it difficult to predict how
many wells will eventually be needed, now long it
would take to achieve cleanup goals, and at what
point the agencies could safely turn off the system.*
In light of this, I suggest the agencies consider
expanding the benefit of the existing and future
vapor vacuum extraction systems beyond regulatory
driven risk reduction and remediation, arid allow
INEL, university, industry, and regulatory partners
to use the WE extraction and monitoring
system(s) as a research "platform" to develop and
test new technologies for subsurface
characterization and modeling, vapor vacuum
extraction and vapor treatment. Applied research
and development activities using this platform
would help us better understand the complexities of
the subsurface, help us optimize the WE process
and be candidates for subsequent technology
transfer to the private sector. Applied research and
development activities associated with this concept
would directly support the Department of Energy's
and EPA's efforts to expand the development of
environmental technologies, as directed by
President Clinton's Environmental Technology
Initiative and EPA's Technology Innovation
Strategy (toe former initiative specifically proposes
to use the national laboratories as testing and
evaluation centers in support of site
characterization technology and use federal facility
sites for full scale demonstrations of innovative
remediation technologies). This platform would
also support increased interaction between local
universities, particularly in the gcosciences and
environmental engineering disciplines, and broaden
our knowledge of VOC fate and transport in the
vadose zone overlying the Snake River Plain
aquifer.
A-15
B-15
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Rcspnmc
Number
Page Number
W14-9
21
Robert M.
Lugar
Our subsurface vapor contaminant problem at
RWMC is not unique; many other DOE sites (e.g.,
Hanford, DOD sites) and even USDA grain
storage sites have discovered similar subsurface
VOC contaminant plumes requiring WE
techniques to remove and treat the vapors. An
INEL WE and VOC treatment research program
could not only help find the optimum treatment
technology for DOE sites, but also assist others to
develop, test, and apply emerging vapor removal
and treatment technologies. VOC emission
abatement, control, and treatment is the most
rapidly growing component of the U.S. air pollution
control industry. Many of the new emission control
requirements of the recently reauthorized Clean Air
Act are aimed specifically at controlling VOC vapor
emissions from a variety of industry categories.
Certain operations at DOE facilities will be
impacted by these new VOC emission
requirements. These regulatory drivers have
created market pull for new and innovative VOC
treatment technologies. Already the list of
emerging technologies for VOC treatment is
growing faster than any other pollution control
area. Emerging vapor treatment technologies
include catalytic oxidation, thermal oxidation,
biological treatment, cryogenic techniques, solar
oxidation, and electron beam destruction. On page
12 of this Proposed Plan it states *... biological
and ultraviolet treatment would require further
development in order to be a viable vapor
treatment option for the large scale application...
.* Why not let scientists and engineers from
INEL/university/industry collaborate on this
problem and use a sidestream of one of the
extraction wells to address this technology
development need?
A-13
B-16
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
Response
Number
Page Number
WI4-1
0
R21
Robert M.
Lugar
The advantages of using the OCVZ as a basis for
conducting subsurface, WE and VOC treatment
research is that the vapor plume is (airly well
characterized, maintains a relatively stable
concentration and composition, and will be
continually monitored during the duration of WF.
operations. Extracted vapor could be made
available for bench or pilot scale treatment studies
using a sidcstream from the extraction well. The
effects of natural barometric 'pumping" could be
studied, enhanced subsurface vapor tracer studies
could be performed, and advanced subsurface
contaminant (ate and transport models could be
calibrated against the monitored plume behavior.
A-10, A-13
W1A-1
1
21
Robert M.
Lugar
The INEL has a noteworthy experience and
capabilities base in this area (e.g., the design.
testing, and optimization of the existing WE
system at RWMC), a cadre of subsurface modeling
opens, the joint INEL/industry development of the
BioCube (a biological VOC treatment technology).
contaminant monitoring experts, engineering
expertise, and state-of-the-art vapor analytical
capabilities. In order for the INEL to survive and
flourish into the next century, we must be attuned
to opportunities to expand our knowledge base and
develop new technologies. The OCVZ work
performed so far has laid the foundation to build
upon, and I would nope the agencies might
recognize that the project has the potential to be
much more than just a remediation project.
A-13
W15-1
JohnR.
Koran
The process of public input after the three agencies
have met in secret to select the preferred alternate
is seriously flawed. It's a farce to even consider
that public comment can change a predetermined
plan. A review of your CERCLA history in Idaho
shows it has never been done. Community
involvement and public comment, in its present
form, only wastes additional taxpayer dollars which
should be used on real risks rather than
hypothetical potential risks of a low order.
A-6
B-17
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
W15-2
WI5-3
W15-4
W15-5
W15-6
W15-7
W15-S
W15-9
W15-1
0
Response
Number
9
10
11
41
NC
39
7
23
43
fjLiitiimilJLr
JohnR.
Horan
John R.
Horan
John R.
Horan
JohnR.
Horan
JohnR.
Horan
JohnR.
Horan
JohnR.
Horan
John R.
Horan
John R.
Horan
Cu^D^DCQt
Note that the main vapor plume has diffused about
100 feet over about 20 years. No mention has
been made of a driving force that is expected to
continue this expansion. I would expect the rate to
decrease to zero as evidenced by 1960 field -
experiments.
All wells as well (no pun intended) as ground
surfaces breath during atmosphere pressure
changes. Have any measurable organic
contaminants been detected by air sampling at the
SDA? This would be real data as compared to
your use of an estimated hazard to hypothetical
workers.
How long has ID been monitoring the vadose
zone?
What changes in the rate of vapor expansion were
noted during the 1993 extraction?
No business enterprise would recommend the
spending of 13-67 million dollars to possibly
remove what has been conservatively overestimated
as a marginally potential health problem with no
noncarcinogenic health effects and acceptable
carcinogenic risks for the public.
Note that every phase in this long sentence is taken
directly, but out of original context, from your
March 1994 statement
No place nave you indicated what amount or
percentage of the offending vapor you expect to
remove or is even a goal of the program 'Believing
you will remove the most significant concentration"
is inadequate.
What is the degree of conservatism introduced in
your risk analysis? 10, 100, or 10,000? The public
should not have to search through pages 6-60 in
the RI report for this vital information.
While it won't matter, my health and technical
choice is Alternative 0.
Inadequate justification has been made to
accelerate this applied experiment over a 2-ycar
period.
Page Number
A-8
A-9
A-9
A-21
Out-of-Scopc/Not Responded To
A-20
A-8
A- 13
A-22
B-18
-------
PUBLIC COMMENTS RECEIVED ON THE
ORGANIC CONTAMINATION IN THE VADOSE ZONE
DURING THE 31 MARCH-30 APRIL 1994 COMMENT PERIOD
Code
W15-1
1
.W15-1
2
W15-1
3
W16-1
WI6-2
W16-3
Response
Number
26
41
NC
32
31
3,32
-
Ouninviut-f f
John R.
Horan
JohnR.
Horan
JohnR.
Horan
George
Lcedom
George
Lcedom
George
Lcedom
As a developmental research project you might be
able to make a case to use existing equipment on
other wells in sequence. You have not considered
this lower keyed approach.
As a taxpayer I would prefer to sec my money
spent on saving lives (e.g.. Boron Neutron Capture
Therapy).
I cannot understand how you can get engineers and
scientists to work on this type of pork barrel project
which is basically unprofessional and unethical
From the presentation I heard at Moscow, Idaho,
on April 21, 1994, 1 feel there is a potential
problem and the action you propose of venting and
destroying the contaminant appears to be very
logical and thought out. I fully agree with your
dean up proposal and the sooner the better.
I realize there is no getting to zero contamination
at any practical cost and there is really no need to.
Carbon tetrachloride, trichloroethylene.
tctrachloroethyiene, and 1, 11,-irichlorocthylcne
havent shown been toxic at low levels.
Therefore, I feel that getting contaminations down
to a reasonable level (minor risk) at reasonable cost
is the best alternative. I feel that you have chosen
the reasonable alternative. Thank you very much.
Page Number
A-15
A-21
«
Out-of-Scope/Not Responded To
A- 17
A-17
• A-6, A-17
B-19
-------
Appendix C
Idaho National Engineering Laboratory
Administrative Record File Index of the
RWMC Vadose Zone Organics RI/FS Operable Unit 7-08
10/20/94
c-i
-------
C-2
-------
Appendix C
Idaho National Engineering Laboratory
Administrative Record File Index of the
RWMC Vadose Zone Organics RI/FS Operable Unit 7-08
10/20/94
ADMINISTRATIVE RECORD VOLUME I
FILE NUMBER
AR3.1 SAMPLING AND ANALYSIS PLAN
Document #: EGG-WM-10175, VoL 1
Title: Sampling and Analysis Plan for the Organic Contamination in the Vadose
Zone
Author Anderson, I. R.
Recipient: N/A
Date: 06/01/92
Document*: EGG-WM-10175, VoL 2
Title: Sampling and Analysis Plan for the Organic Contamination in the Vadose
Zone
Author Anderson, L R.
Recipient: N/A
Date: 06/01/92
ADMINISTRATIVE RECORD VOLUME II
AR33 . WORK PLAN
Document #: ERD-025-92
Title: Organic Contamination in the Vadose Zone Remedial
Investigation/Feasibility Study Work Plan
Author Lyle, J. L.
Recipient: Pierre, W.; Nygard, D.
Date: 02/27/92
Document #: EGG-WM-10049
Title: Final Work Plan for the Organic Contamination in the Vadose Zone
Author: Chatwin, T. D.
Recipient: N/A
Date: 06/01/92
C-3
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR3.4 REMEDIAL INVESTIGATION
A Document #: ER-WED-076
Title: Long Term Testing at OCVZ (OU-8), Possible Origin of Chloroform at the
RWMC
Author Downs, W. C .
Recipient: ARDC ;
Date: 05/04/94
AR3.10 SCOPE OF WORK
* Document #: EGG-ERD-10376, Rev. 7
Title: Scope Of Work for Organic Contamination in the Vadose Zone Remedial
Investigation/Feasibility Study
Author Matthern, G. E
Recipient: N/A ^
Date: 06/01/92
AR3.12 RI/FS REPORTS
Document #: EGG-ER-10684, VoL 1
Title: Remedial Investigation/Feasibility Study Report For The Organic
Contamination in the Vadose Zone—Operable Unit 7-08
Volume I: Remedial Investigation
Author Duncan, F. L.
Recipient: N/A
Date:. 12/01/93
ADMINISTRATIVE RECORD VOLUME HI
Document #: EGG-ER-10684, VoL 2
Title: RI/FS Report For The Organic Contamination in the Vadose Zone-
Operable Unit 7-08
Volume II: Remedial Investigation Appendices
Author: Duncan, F. L.
Recipient: N/A
Date: 12/01/93
C-4
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
ADMINISTRATIVE RECX)RD VOLUME IV
FILE NUMBER
AR3.12
RI/FS REPORTS (continued)
Document #: EGG-ER-10684, Vol. 3
Title: RI/FS Report For The Organic Contamination in the Vadosc Zone-
Operable Unit 7-08
Volume II: Feasibility Study
Author Hamel, C M.
Recipient: N/A
Date: 12/01/93
* Document #: OPE-ER-70-94
Title: Transmittal of Final Inserts for the OCVZ Final RI/FS
Author Green, L,
Recipient: Pierre, W.; Nygard, D.
Date: 03/24/94
AR3.17 RI/BRA REPORTS
* Document*: AM/ERWM-ERD-092-92
Title: Organic Contamination in the Vadose Zone Remedial
Investigation/Feasibility Study
Author Lyle, J. L.
Recipient: Pierre, W.; Nygard, D.
Date: 10/09/92
Document #: AM/ERWM-ERD-017-93
Title: Transmittal of Draft Organic Contamination in the Vadose Zone Remedial
Investigation and Baseline Risk Assessment Report
Author Lyle, J. L
Recipient: Pierre, W.; Nygard, D.
Date: 03/03/93
C-5
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR3.18 ENVIRONMENTAL.
* Document #: 5620
Title: NEPA—Environmental Assessment of Remediation of Organic
Contamination in the Vadose Zone at the INEL
Author DOE-ID
Recipient: Administrative Record
Date: 02/25/94
AR3.19 FINDING OF NO SIGNIFICANT IMPACT
* Document #: 5619
Title: Draft Finding of No Significant Impact for the Remediation of the Organic
Contamination in the Vadose Zone
Author DOE-ID
Recipient: N/A
Date: 02/01/93
AR3.2D TREATABBLITY STUDY
Document*: AM/ERWM-ERD-085-92
Title: Vapor Vacuum Extraction Treatability Study at the RWMC
Author Macdonald, D. W.
Recipient: Nygard, D.
Date: 09/11/92
* Document*: EGG-WM-10132
Title: . Final Work Plan for the OCVZ OU 7-08 Pilot Scale Treatability Study
Author Herd, M.
Recipient: N/A
Date: 03/01/94
* Document #: OPE-ER-69-94
Title: Transmittal of the Draft Treatability Study Report for OCVZ (OU-7-08)
Author Green, L. A
Recipient: Pierre, W.; Nygard, D.
Date: 03/25/94
C-6
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR4J PROPOSED PLAN
* Document #: 5642
Title: Proposed Plan for Organic Contamination in the Vadosc Zone
Author INEL Community Relations
Recipient: N/A
Date: 03/01/94
* Document #: 5672
Title: Transmitla! of the Proposed Plan for Organic Contamination in the Vadosc
Zone, Idaho National Engineering Laboratory
Author Robison, S. A.
Recipient: Bums, T. F.
Date: 02/18/94
AR5.1 RECORD OF DECISION
A Document #: OPE-ER-152-94
Title: Transmittal of the Draft Record of Decision for Organic Contamination in
the Vadose Zone, RWMC, INEL
Author Lyle, J. L.
Recipient: Pierre, W.; Nygard, D.
Date: 07/11/94
* Document #: 5761
Title: Record of Decision for Organic Contamination in the Vadose Zone,
RWMC, INEL
Author DOE-ID, EPA, IDHW
Recipient: N/A
Date: 11/08/94
AR7.8 OFFSITE WASTE SHIPMENTS
* Document #: 5609
Title: Approval of an EG&G Idaho Waste Shipment
Author: Lytle, J. E.
Recipient: Burns, T. F.
Date: 11/22/93
C-7
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR7.9 SECRETARIAL POLICY
* Document*: OPE-ER1-056-94
Title: Changes in the Environmental Restoration (ER) Program Due To The
Secretarial Policy on the National Environmental Policy Act (NEPA)
Author Green, L. A.
Recipient: Addressees
Date: 07/13/94
AR10.4 PUBLIC MEETING TRANSCRIPTS
* Document #: 5703
Title: Public Meeting Transcripts for the Organic Contamination in the Vadosc
Zone (OCVZ)
Author Ecology and Environment, Inc.
Recipient: N/A
Date: 05/24/94
This document can be found in the INEL OU 8-07 Administrative Record Binder
AR10.6 PRESSRELEASES
* Document #: 5640
Title: DOE Seeks Public Comment on Organic Contamination in the Vadosc Zone
Author N/A
Recipient: N/A
Date: 03/01/94
AR12.1 EPA COMMENTS
* Document #: 5358
Title: Comments for Draft Work Plan for Organic Contamination in the Vadosc
Zone Remedial Investigation/Feasibility Study, Operable Unit 7-8, December
1991
Author Pierre, W.
Recipient: Lyle,' J. L.
Date: 02/26/92
C-8
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR12.1
EPA COMMENTS (continued)
Document #: 5674
Title: INEL RWMC—Draft Final Work Plan for The Organic Contamination in the
Vadose Zone, Operable Unit 7-08 Focused Remedial Investigation /
Feasibility Study, Dated
May 1992
Author Nearman, M. J.
Recipient: Macdonald, D.
Date: 05/21/92
Document *: 5357
Title: INEL WAG 7—Draft RI Report for the Organic Contamination in the
Vadose Zone (OU 7-08), February 1993
Author Nearman, M. J.
Recipient: Macdonald, D.
Date: 04/29/93
Document #: 5613
Title: EPA Comments on the Draft RI/FS Report for the Organic Contamination
in the Vadose Zone OU 7-08, 3 volumes, dated August 1993
Author Nearman, M. J.
Recipient: Macdonald, D.
Date: 11/04/93
Document #: 5628
Title:. EPA Comments: INEL OU 7-08 Draft Final RI/FS Report
Author Jones, E.
Recipient: Green, L.
Date: 02/14/94
Document #: 5707
Title: EPA Concurs: Preliminary Design Summary Report for OCVZ, RWMC,
INEL
Author Pierre, W.
Recipient: Green, L.
Date: 05/18/94
C-9
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER
AR12.1
EPA COMMENTS (continued)
Document #: 5765
Title: EPA Comments on the Record of Decision for the OCVZ
Author Wilkening, R. M.
Recipient: Green, L.
Date: 08/22/94
AR122
EDHW COMMENTS
Document #: 5675
Title: Technical Review Comments for Draft Final Focused RI/FS Work Plan for
Organic Contamination in the Vadosc Zone
Author Nygard, D.
Recipient: Lyle, J. L.
Date: 05/22/92
Document #: 56%
Title: Review of DOE-ID Letter Dated 09/11/92 Providing Air Emissions
Information for Meeting the Substantive Requirements of Idaho's Air
Quality Regulations, WE Treatability Study at the RWMC
Author Nygard, D.
Recipient: Lyle, J. L.
Date: 10/16/92
Document #: 5355
Title: " Review of EG&G Letter Dated November 9, 1992 Providing Air Emissions
Information for the Pilot Scale Treatability Study, Operable Unit (OU 7-08)
at the RWMC
Author Nygard, D.
Recipient: Lyle, J. L.
Date: 11/30/92
Document #: 5356
Title: Review Comments for Draft RI Report for the Organic Contamination in
the Vadosc Zone, (EGG-ER-10684)
Author Nygard, D.
Recipient: Macdonald, D.
Date: 04/21/93
C-10
-------
RWMC VADOSE ZONE ORGANICS Rl/FS OU 7-08 10/20/94
FILE NUMBER
AR122 IDHW COMMENTS (continued)
* Document #: 5571
Title: Technical Review Comments for the Draft Remedial Investigation /
Feasibility Study Report for the Organic Contamination in the Vadose Zone
Operable Unit 7-08
Author. Koch, D. F.
Recipient: Williams, A. C.
Date: 11/03/93
A Document #: 5708
Title: Confirmation of OCVZ Well Installation Modification
Author Koch, D.
Recipient: Green, L.
Date: 05/16/94
A Document #: 5766
Title: IDHW Review of the Record of Decision—Declaration of
OCVZ-OPE-ER-152-94
Author Koch, D.
Recipient: Green, L.
Date: 08/26/94
AR123 DOE RESPONSE TO COMMENTS
Document #: ERD1-081-92
Title:. Scope for Organic Contamination in the Vadose Zone Remedial
Investigation/Feasibility Study
Author Lyle, J. L.
Recipient: Pierre, W.; Nygard, D".
Date: 03/27/92
A Document #: 5588
Title: Resolution on the Comments for the Draft Remedial Investigation Report
for the Organic Contamination in the Vadose Zone (Operable Unit 7-08).
February 1993
Author: EG&G Idaho, Inc.
Recipient: IDHW
Date: 02/01/93
C-ll
-------
RWMC VADOSE ZONE ORGANICS RI/FS OU 7-08 10/20/94
FILE NUMBER ~ "*
AR123 DOE RESPONSE TO COMMENTS (continued)
* Document #: OPE-ER-004-94
Title: DOE Response to IDHW and EPA Comments on the Draft RI/FS for
Organic Contamination in the Vadose Zone OU 7-08
Author Green, L,
Recipient: Pierre, W.; Nygard, D.
Date: 01/13/94
A Document*: OPE-ER-267-94
Title: DOE Response to IDHW and EPA Comments on the Draft Record of
Decision (ROD) for Organic Contamination in the Vadose Zone (OCVZ)
OU 7-08 at the RWMC, INEL
Author Green, L,
Recipient: Pierre, W.; Nygard, D.
Date: 09/30/94
AR12.4 REQUEST FOR EXTENSION
* Document*: ERDl-118-92
Title: Extension Of Comment Period For Organic Contamination in the Vadose
Zone (OCVZ) Remedial Investigation/Feasibility Study
Author Lyle, J. L.
Recipient: Pierre, W.; Nygard, D.
Date: 03/27/92
This Administrative Record Index is complete.
DOE-ID WAG Manager Date
LITCO WAG Manager Date
C-12
------- |