DRC-2000-001062 - 0901a068807b3000

GJO-2000-163-TAR
MAC-MSG 2.2.5
Monticello Mill Tailings Site
Operable Unit Ill
Interim Remedial Action
Progress Report
July 1999 - July 2000
September 2000
Work Performed Under DOE Conlracl No. DE-AC13-96GJ87335 for the U.S. Departmenf of Energy Approved lorpublic release; dislribullon is unlimiled.
MAC-MSG 2.2.5
Monticello Mill Tailings Site
Operabig Unit 111
Interim Remedial Action
Progress Report
July 1999-July 2000
September 2000
Prepared for
U.S. Department of Energy
Albuquerque Operations Office
Grand Junction Office
Project Number MSG-035-001 1-01-000
Document Number Q0019700
Work Performed Under DOE Contract Number DE-AC13-96GJ87335
Task Order Number MAC00-03
Documcnt Number Q0019700 Signature Page
Signature Page
Interim Remedial Action Work Plan
for
Operable Unit 111-Surface Water and Ground Water
Monticello Mill Tailings Site
September 2000
Prepared By:
.
Monticello Groundwater
Reviewed By: -
Major Projects
Approved By:
Joel D. ~knbick, ProiectITechnical Manaser .2
U.S. ~epr\dment of Energy Grand Junction Office
DOFJGrand Jseclion OITlce OU Ill I&\ P~rogers Keporl
September 20WJ iii
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Document Number Q0019700 Contents
Contents
Page
Acronyms ....................................................................................................................................... ix
1.0 Introduction ............................................................................................................................ 1-1
. . 2.0 Inst~tut~onal Controls ............................................................................................................. 2-1
3.0 Millsite Dewatering and Treatment ....................................................................................... 3-1
4.0 Monitoring and Additional Data Collection .......................................................................... 4-1
4.1. Surface Water and Ground Water Monitoring .................................................................. 4-1
4.1.1 Surface Water Results ................................................................................................. 4-2
4.1.2 Ground Water Results ............................................................................................... 4-10
4.2. Data Collection ............................................................................................................. 4-27
4.2.1 Distribution of Metal COCs in Vadose Zone Soil .................................................... 4-27
4.2.2 Characterize Mobility of COCs in Vadose Zone ...................................................... 4-33
4.2.3 Installation and Monitoring of Temporary Wells .................................................... 4-59
4.2.4 Installation and Monitoring of Permanent Wells ...................................................... 4-69
4.2.5 Evaluate Contaminant Mobility in Alluvial Aquifer ................................................ 4-69
4.2.6 Select New Locations for Long-Term Surface Water Monitoring ................... ........ 4-69
4.2.7 South Millsite Source Investigation .......................................................................... 4-70 . . 5.0 PeRT Wall Treatab~l~ty Study ................................................................................................ 5-1 . . 5.1. Performance Mon~tonng ................................................................................................... 5-1
5.2. Flow Evaluation ................................................................................................................ 5-6 . . 6.0 Remedial Invest~gat~on ......................................................................................................... 6-1
7.0 Feasibility Study .................................................................................................................... 7-1
7.1. Ground Water Modeling Status ....................................... ; ................................................ 7-1
7.2. Preliminary Remediation Goals ........................................................................................ 7-1
7.2.1 Surface Water ............................................................................................................. 7-2
7.2.2 Ground Water .............................................................................................................. 7-2
7.3. Point of Compliance and Area of Attainment ................................................................... 7-4 . . 7.4. Remed~atlon Time Frame ................................................................................................ 7-4
7.5. Remedial Alternatives ....................................................................................................... 7-5
8.0 Applicable or Relevant and Appropriate Requirements ....................................................... 8-1
8.1. Federal ARARs ................................................................................................................. 8-1
8.1.1 Safe Drinking Water Act ............................................................................................ 8-1
8.2. State of Utah ARARs ........................................................................................................ 8-8
8.2.1 Drinking Water ........................................................................................................... 8-8
8.2.2 Air Quality ............................................................................................................... 8-12
8.3. To-Be-Considered ........................................................................................................... 8-14
9.0 References .............................................................................................................................. 9-1
DOWGmd Junction Oflice OU Ill IRA Progress Reporl
September 2000 v
Contents Document Number Q0019700
Table 4.2.1-1.
Table 4.2.1-2.
Table 4.2.1-3
Table 4.2.2-1.
Table 4.2.2-2.
Table 5.1-1.
Table 7.2.1-1.
Table 7.2.2-1.
Table 8.1-1.
Table 8.2-1.
Figure 1.1 .
Figure 1.2 .
Figure 4.1-1.
Figure 4.1-2.
Figure4.1.1-1.
Figure 4.1.2-1.
Figure 4.1.2-2.
Figure 4.1.2-3.
Figure 4.1.24.
Figure 4.1.2-5.
Figure 4.1.24.
Figure 4.1.2-7.
Figure 4.1.2-8.
Figure 4.2.1-1.
Figure 4.2.1-2.
Figure 4.2.1-3.
Figure 4.2.14.
Figure 4.2.1-5.
Figure 4.2.14.
Figure 4.2.2-1.
Figure 4.2.2-2.
Figure 4.2.2-3.
Figure 4.2.24.
Figure 4.2.2-5.
Figure 4.2.2-6.
Figure 4.2.2-7.
Figure 4.2.2-8.
Tables
Page
Summary of Surface Sample Results ............................................................ 4-28
Depth Samples ............................................................................................... 4-30
Summary Statistics for Depth Soil Samples ............................................... 4-31
................................................................. Vadose Zone Column Conditions 4-34
Concentrations of Arsenic. Uranium and Vanadium in Soils Before
Column Testing ............................................................................................. 4-36
Ground Water Transect Concentrations Through Gate Transects .................. 5-2
Surface-Water Preliminary Remediation Goals ............................................. 7-2
Ground Water Preliminary Remediation Goals ............................ ................. 7-3
Federal ARARs for OU 111 Surface Water and Ground Water ....................... 8-2
State ARARs for OU 111 Surface Water and Ground Water ........................... 8-9
Figures
Monticello Mill Tailings Site. San Juan County. Utah ................................... 1-2
Monticello Mill Tailings Site. Operable Unit I11 Schedule ............................. 1-3
Ground Water and Surface Water Monitoring Network-West ....................... 4-3
Ground Water and Surface Water Monitoring Network-East ........................ 4-5
........................................................................ Surface Water Sample Results 4-7
Ground Water Sample Locations and Results-Arsenic ................................ 4-11
Ground Water Sample Locations and Results-Manganese ........................... 4-13
Ground Water Sample Locations and Results-Molybdenum ....................... 4-15
Ground Water Sample Locations and Results-Nitrate .................................. 4-17
.............................. Ground Water Sample Locations and Results-Selenium 4-19
............................... Ground Water Sample Locations and Results-Uranium 4-21
Ground Water Sample Locations and Results-Vanadium ............................ 4-23
Ground Water Sample Results-Nitrate ........................................................ 4-25
Arsenic Concentrations in Surface Soils ....................................................... 4-28
Uranium Concentrations in Surface Soils ..................................................... 4-28
Vanadium Concentrations in Surface Soils ................................................... 4-29
Arsenic Depth Profile .................................................................................... 4-32
.................................................................................. Uranium Depth Profile 4-32
................................................................................ Vanadium Depth Profile 4-33
..................................... Locations of Soil Samples Used in Column Testing 4-35
Uranium Desorption From RVZ Soil-Loyd's Lake Leach All Samples ...... 4-39
Uranium Desorption From RVZ Soil-Loyd's Lake and Ground Water
Leached Samples ........................................................................................... 4-41
Uranium Desorption From RVZ Soil-Loyd's Lake and Golf Course
................................................................................ Water Leached Samples 4-43
Arsenic Desorption From RVZ Soil-Loyd's Lake Leach All Samples ........ 4-45
Arsenic Desorption From RVZ Soil-Loyd's Lake and Ground
............................................................................................... Water Leaches 4-47
Arsenic Desorption From RVZ Soil-Loyd's Lake and Golf
............................................................................................ Course Leaches 4-49
Vanadium Desorption From RVZ Soil-Loyd's Lake Leach All Samples .... 4-51
OU Ill IRA Progress Report DOWGrand Junction Office
vi September 2000
Document Number QO019700 Contents
Figures (continued)
Page
Figure 4.2.2-9. Vanadium Desorption From RVZ Soil-Loyd's Lake Leach All Samples
Except 3051 ................................................................................................... 4-53
Figure 4.2.2-10. Vanadium Desorption From RVZ Soil-Loyd's Lake and Ground
Water Leaches ............................................................................................. 4-55
Figure 4.2.2-1 1. Vanadium Desorption From RVZ Soil-Loyd's Lake and Golf Course
Leaches ........................................................................................................ 4-57
Figure 4.2.3-1. Locations of Temporary Monitoring Wells-West ..................................... 4-61
........................................ Figure 4.2.3-2. Locations of Temporary Monitoring Wells-East 4-63 - ............... Figure 4.2.3-3. Well Location Map PeRT Area ................................................ 4-65
..................................................... Figure 4.2.3-4. Monitoring Locations in PeRT Gate Area 4-67
Figure 4.2.7-1. Temporary Wells Near Seeps 4307 and 521 5 ............................................... 4-71
Figure 5.1-1. PeRT Wall Locations With Water Quality Results During This
Reporting Period ........................................................................................... 5-3
........................................ Figure 5.2-1. PeRT Wall Table Surface and Saturated Thickness 5-9
......................................................... Figure 5.2-2. PeRT Wall Reactive Gate Water Table 5-1 1
Appendices
Appendix A
Appendix B
B-1
B-2
Appendix C
Appendix D
D-1
D-2
D-3
Appendix E
E-1
E-2
Appendix F
F-1
F-2
F-3
Appendix G
G- 1
Ground-Water Management Policy for the Monticello Mill Tailings Site
and Adjacent Areas
Uranium Removal During Millsite Dewatering
Interim Remedial Action Calculations
Draft Feasibility Study Calculations
Monticello Mill Tailings Site, Operable Unit I11
Program Directives
Surface Water and Ground Water Monitoring Data
Surface Water Data
Ailuvial Ground Water Data
Bedrock Ground Water Data
Time-Concentration Plots
Surface Water Levels
Ground Water Levels
Water Level and Stream Discharge Data
Water Level Measurement Data
Well Hydrographs
Surface Water Discharge Data
Soil Results
Surface Soil Sample Results
Depth Sample Soil Results
DOUGrand Junction Office OU 111 IRA Progress Reporl
September 2000 vii
Contents Document Number Q0019700
Plates
Plate 1 Suri ice Soil Sample Results for Arsenic on the Millsite
2 Suriace Soil Sample Results for Uranium on the Millsite
3 Surface Soil Sample Results for Vanadium on the Millsite
OU 111 IRA Progress Report WWGrand Junclion Ofiice viii Scl~lembcr ZOO0
Document Number Q0019700 Acronyms
Acronyms
COC
COE
DOE
EPA
ESL
FS
IRA
Kd
kg
VdL
MMTS
ou
pCi1g
PeRT
PP~
ppb
RA
RD
RI
ROD
RVZ
UDEQ
UPDES
WWTP
ZVI
contaminant of concern
U.S. Army Corps of Engineers
U.S. Department of Energy
U.S. Environmental Protection Agency
Environmental Sciences Laboratory
feasibility study
Interim Remedial Action
distribution coefficient
kilograms
micrograms per liter
milliliters per gram
Monticello Mill Tailings Site
operable unit
picocuries per gram
permeable reactive treatment
parts per billion
parts per million
remedial action
remedial design
remedial investigation
Record of Decision
residual vadose zone
Utah State Department of Environmental Quality
Utah Pollutant Discharge Elimination System
Wastewater Treatment Plant
zero valent iron
DOWGrand Junction Office OU 111 IRA Propers ReporI
September 20W ix
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Document Number Q0019700 introduction
1.0 Introduction
In September 1998, the Record of Decision for an Interim Remedial Action at the Monticello
Mill Tailings Site, Operable Unit III-Surface Water and Ground Water, Monticello, Utah,
(DOE 1998a) was signed by the U. S. Environmental Protection Agency (EPA) and the Utah
Department of Environmental Quality (UDEQ). The Monticello Mill Tailings Site (MMTS) is
located in southeast Utah, in and near the city of Monticello in San Juan County (Figure 1-1).
Operable Unit (OU) I11 encompasses contaminated ground water and surface water at and
downgradient of the former Monticello Millsite. The former Millsite is a 110-acre tract of land
owned by the city of Monticello. Mill tailings and associated contaminated material remained on
the Millsite as a result of historical vanadium and uranium milling operations; these materials
were the primary source of contamination in ground water and surface water. Pursuant to the
Record of Decision (ROD) (DOE 1990) for the MMTS, contaminated materials from OU I (the
Millsite) and OU I1 (peripheral properties) were excavated and placed in an on-site repository
designed for their permanent storage. The ROD for MMTS also stipulated that a ROD for OU I11
would be produced when sufficient data were gathered through a focused remedial
investigation/feasibility study (RI/FS).
Previously, OU I11 also encompassed contaminated soil and sediment deposited downstream of
the Millsite in and adjacent to Montezuma Creek. However, during the spring of 1999
subsequent to remediation of the contaminated properties, a decision was made to address the
remedy selection for the OU I11 soil and sediment area along Montezuma Creek under OU I1
(peripheral properties) of the MMTS.
The RI for OU I11 began with site characterization activities in the fall of 1992; data collection
for the purposes of completing the RI report (DOE 1998b) and preparing a draft FS report
(DOE 1998c) continued through June 1996. During review of the draft FS report in the summer
of 1997, DOE, EPA, and UDEQ mutually agreed that it was not possible at that time to
definitively predict the effects that Millsite remediation would have on tlte ground-water and
surface-water systems. A decision was made to conduct an interim remedial action (IRA) and
revise the draft FS after post-Millsite remediation-conditions in ground water and surface water
had stabilized. The draft final FS is scheduled to be submitted to EPA and UDEQ in
August 2004. A generalized schedule showing major OU 111 activities up to and including the
ROD is shown in Figure 1-2.
The IRA was designed to
prevent the use of contaminated ground water by implementing institutional controls,
remove contaminants from the ground water and, in turn, the surface water, by treating
extracted ground water through dewatering activities,
continue to monitor the changing conditions in the alluvial aquifer and in surface water and
collect data to characterize post-remediation conditions at the site, and
evaluate the feasibility of a Permeable Reactive Treatment (PeRT) wall for in-situ treatment
by conducting a pilot-scale treatability study.
WUGrand Junction OKtce OU Ill IRA Progress Report
September 2000 1-1
Introduction Document Number Q0019700
I I
w 0 m ,m ,w LLII_I
Figure 1-1. Monticello Mill Tailings Site, San Juan County, Utah
OU Ill IRA Progress Report WWGrand Junction Office
1-2 September 2000
F \ e > -
i FEASlElLlTY STUDY
5
&V 2
I n
, . PROPOSED PLAN
A 5 >. . . 6 ! ! P , : A, 8
9 '~:~j 3 i= 8 S' 2 $ 2 :> . 4. r - 2
RECORD OF DECISION 2 53 a ~$1 -' ra i !
tsi q 6 g gi e el
.U 2t v a B
v n
Figure 1-2. Monlicello Mill Tailings Site, Operable Unit 111, Schedule
n"F'Cr-mll lltnrtinnO(7irr OU 111 11U Progrcrs Repon
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Document Number 00019700 Introduction
The MonticeNo Mill Tailings Site, Operable Unit III, Interim Remedial DesigdRemedial Action
(RD/RA) Work Plan for Operable Unit III- Sujface Water and Ground Water (DOE 1999a) was
prepared to give an overview of the management, work elements or tasks, and schedules for
completion of the IRA. A draft Monticello Mill Tailings Site, Operable Unit III, Interim
Remedial Action Work Plan (DOE 1999b) was prepared to identify the data collection and PeRT
wall treatability study activities that will be undertaken as part of the IRA. A decision was made
in August 1999 to revise the IRA Work Plan to 1) include information from the RD/RA Work
Plan; 2) expand the activities discussed to include all activities necessary to get to the final ROD;
and 3) include a commitment to perform an annual analysis of the applicable or relevant and
appropriate requirements (ARARs). The IRA Work Plan is anticipated to be finalized in
October 2000.
This progress report has been prepared to summarize the progress made in performing the four
IRA activities outlined in the previous paragraph since the signing of the ROD for the IRA in
September 1998 through June 2000. Progress~eports are prepared annually and will include an
update to the ARARs analysis presented in the draft FS (DOE 1998c), any finalized Program
Directives that may be prepared during the previous year that cover investigative activities, and
they will also summarize any progress made in other activities necessary to get to the final ROD.
DOElGrand lunction Offlee OU Ill IRA Progress Report
September 2000 1-5
Introduction Docurne~~t Number Q0019700
End of current text
OU I11 IRA Progress Report DOUGrand Junction Ofice
1-6 September 2000
Docun~ent Number Q0019700 lnstitutio~ial Controls I
2.0 Institutional Controls
The Utah State Engineer's Office informally approved DOE'S request for institutional controls
for the shallow alluvial aquifer on October 21, 1998. At that time the State Engineer's office
assumed responsibility for preparation of a ground-water management policy, for fulfilling the
public participation requirements associated with the implementation of institutional controls,
and for implementing the institutional controls. On March 18, 1999, the State Engineer issued
notice of a public meeting regarding the proposal to prohibit drilling of shallow alluvial wells in
the contaminated areas along Montezuma Creek. Property owners that would be affected by the
institutional control received personal invitations to the meeting. The meeting was held on
April 7, 1999 at the San Juan County Courthouse and a draft ground-water management policy
was made available. Only one person (an affected property owner) attended the meeting. The
property owner questioned whether his potential use of a well completed in the deeper Burro
Canyon aquifer would be affected by the institutional control. The property owner was told that
because the Burro Canyon aquifer has not been contaminated by the overlying shallow aquifer,
his use of the well would not be affected by the institutional control.
The State Engineer's office did not receive comments during the 30-day public comment period.
At the close of the public comment period the Ground-Water Management Policy for the
Monticello Mill Tailings Site and Adjacent Areas (a copy is provided in Appendix A) was issued
and became effective May 21, 1999. The policy states that new applications to appropriate water
for domestic use from the shallow alluvial aquifer within the boundaries of the Monticello
Ground-Water Restricted Area will not be approved; existing water rights are not affected. Also,
change applications proposing to divert and use water from the shallow aquifer for domestic
purposes will not be approved. The policy states that applications to drill wells into the deeper
Burro Canyon formation would be approved if it could be demonstrated that the well
construction would not allow the shallow alluvial water to flow to the deeper formation. A map
of the Monticello Ground-Water Restricted Area was attached to the Ground-Water Management
Policy.
The State Engineer's office conducted a search of their database for existing water rights
appropriating water for domestic use. Only one such water right, Water Right 094130, exists
within the Monticello Ground-Water Restricted Area. The water right is to 0.01 cubic foot per
second of flow from a surface diversion of an unnamed spring. A field visit to the location of the
water right was made on April 7,1999. Water appears to have been taken from a very shallow
well or pumped from a sump to supply what is now an abandoned, dilapidated house nearby. The
property owner was contacted about relinquishing the existing water right or agreeing not to
exercise the water right until it is determined that the risk to human health is acceptable.
DOE made the decision to pursue obtaining the water right along with purchasing restrictive
easements from property owners who own property along Montema Creek on which
supplemental standards were applied.'The restrictive easement would prohibit the building of a
habitable structure and the removal of soils from within the easement area. One of the property
owners is also the owner of the water right. The U.S. Army Corps of Engineers (COE) obtained
appraisals in order to determine fair market value of the easement and water right. Offers were
mailed to the property owners by the COE via letter dated June 21,2000.
DOElGrand Junction Office OU I11 IRA Progress Reporf
September ZOO0 2-1
Institutional Controls Document Number Q0019700
A meeting was held on August 1,2000, with the affected property owners, COE, DOE, and
DOE'S contractor to discuss the offers. The three property owners at the meeting were unwilling .- ~
to accept the offers presented. The owners concerns were:
Offers presented for the easement do not represent fair market value
. There appeared to be a discrepancy in the average valuation price (dollars per acre) of the
easement from one property to the next
. The highest and best use identified in the appraisal was not correct and the easement would
impact the owners future development plans of the property. Potential development plans
mentioned by the property owners included a gravel extraction operation, subdivision for
housing development, and fishing cabins.
. As stated, the restrictive easement would also prohibit plowing, discing, or other disturbance
activities. The owners were concerned that activities such as placing a culvert in the stream
would not be permitted. The owners were informed that the language prohibiting plowing,
discing and other disturbance activities would be removed from the easement. Language
clarifying that disturbed soils will be placed back in the easement area would be added.
Purchase of the water right was not discussed at the August 2000 meeting but is currently tied to
resolution of problems discussed above associated with purchase of the restrictive easements.
The COE will follow-up with the propedy owners to explain the Government position on the
appraisals and the fair market value determination. DOE requested that the San Juan County
Commission consider putting in place a requirement that would allow DOE to scan future house
footprints. This would eliminate the need for the restrictive easement. The proposal was
presented to the-San Juan County Commission on August 21,2000. The commissioners were not
in favor of using the county permitting process to effect a use restriction. The COE and DOE will
continue to work with the landowners to resolve their concerns.
With regard to the institutional controls on ground water, DOE accepts responsibility for
ensuring that the Ground-Water Management Policy is working. DOE will conduct annual
inspections of the properties to look for any evidence of well installations or ground water use.
The first inspection occurred during October 1999; no new private wells have been installed and
there is no evidence of domestic use of the alluvial ground water in the OU 111 area. The next
inspection is scheduled for October 2000. The results of the October 2000 inspection will be
reported in the next annual IRA progress report.
OU Ill IRA Progress Report DOWGrand Junction Oftice
2-2 September 2000
Document Number Q0019700 Millsite Dewatering and Treatment
3.0 Millsite Dewatering and Treatment
The primary objective of Millsite dewatering and treatment was to facilitate excavation and
removal of mill tailings and contaminated soil that extended below the water table. It was also
realized that in treating contaminated ground water, contaminants would be permanently
removed from the ground water system, thereby, positively affecting ground water and surface-
water quality.
Ground-water removal at the Millsite was initiated in March 1998 with construction of a
dewatering trench along the western side of the Carbonate Pile. Up to 100 gallons per minute
entered the trench and flowed to Pond 3. In May 1998, an "L" shaped trench was constructed
along the west and south sides of the Carbonate Pile. The trenches extended to bedrock and thus
intercepted all alluvial ground water. Water was pumped from the trenches to allow remediation
of the Carbonate Pile. On occasion, dewatering was halted due to insufficient capacity at Pond 3.
The Carbonate Pile excavation eventually extended to bedrock. Uncontaminated ground water
that discharged to the excavation from the west was then routed to Montezuma Creek to reduce
the inflow to Pond 3 and reduce treatment volumes. As excavation progressed eastward to
include the East Pile, very little ground water was encountered. Intercepting ground water from
the west and pumping in the Carbonate Pile area contributed to the dry conditions in the East
Pile.
Some of the water recovered was used for dust control; the rest was treated at the waste water
treatment plant (WWTP) to Utah Pollutant Discharge Elimination System (UPDES) standards
before discharge to Montezuma Creek or use for dust control. Prior to 1998, approximately
4 million gallons of water were treated at the site. In March 1998, a reverse osmosis system was
added to the treatment process. The WWTP operated from April 1998 through the winter and in
May 1999, the WWTP was dismantled. Since April 1998, the plant processed over 50 million
gallons.
OU I11 involvement in dewatering and treatment activities was limited to acquisition of data on
volumes and concentrations of water being removed from the surface-water and ground-water
systems. Using this data, it is estimated that between about 50 and 100 kilograms (kg) of
uranium were removed from (and as source to) the alluvial aquifer during dewatering and
treatment plant operation. This assumes a total treatment volume of 54 million gallons of water
with uranium concentrations averaging between 0.5 and 1 mg/L (see Appendix B-1 for
calculation methods). Since shutdown of the WWTP, it is estimated that 4,080,000 gallons of
contaminated water from Pond 4 were used for dust suppression which represents between 7.5
and 15 kg of additional uranium removed from the alluvial system (Appendix B-1). This
combined mass can be compared to a mass of 1,800 kg uranium (dissolved and sorbed) that was
estimated to be present in the alluvial aquifer prior to Millsite remediation (see Appendix B-2,
Calculation Q00076AA). The uranium removed from the alluvial system during approximately
one year of continuous ground-water treatment is therefore approximately 3 to 6 percent of the
total inventory. This excludes the mass of sorbed uranium that was excavated and removed from
the system during surface remediation. As the estimates in Appendix B-2 indicate (Calculation
Q00076AA), the contribution of the sorbed phase to the total mass inventory is much greater
than the solute phase, even if the distribution coefficient (Kd) is only 1 mL/g (uranium example).
WUGrand Junction Olliee OU III IRA Progress Report
September 2000 3-1
Millsite Dewatering and Treatment Docunlent Nuii~ber Q0019700
End of current text
OU 111 IRA Progress Report DOEJGrand Junction 0%~.
3-2 Septenibcr 2000
Document Number Q0019700 Monitoring and Additional Data Collection
4.0 Monitoring and Additional Data Collection
The monitoring and additional data collection component of the IRA consists of two primary
tasks: surface-water and ground-water monitoring and characterization of post-Millsite
remediation conditions.
4.1. Surface Water and Ground Water Monitoring
Quarterly surface-water and ground-water monitoring is ongoing at the site. Monitoring in
October 1999 was according to the Monticello Mill Tailings Site, Operable Unit III, Interim
Remedial Action, Surface Water and Ground Water Monitoring Plan (DOE 1999~). Monitoring
in 2000 was according to the Monticello Mill Tailings Site, Operable Unit IIJ Interim Remedial
Action, Surface Water and Ground Water Monitoring Plan (DOE 1999d). Changes to the
scheduled activities were documented in Program Directives; Program Directives issued during
the year are presented in Appendix C. Monitoring associated with the PeRT treatability study is
discussed in Section 5.0.
Water quality samples were collected from specified locations according to a variable schedule
(Figures 4.1-1 and 4.1-2). Field measurement data, common ion and metals concentrations, and
radioactivity data organized by sampling locafion are presented in Appendix D. Metals data
presented in Appendix D are limited to the contaminants of concern (COCs) established for
OU 111 in the RI, except for cobalt, copper, lead, and zinc, which were deleted as COCs per the
recommendations presented in the MonticeNo Mill Tailings Site, Operable Unit III, Surface
Water and Ground Water Data Summary Report-October 1998-July 1999 (DOE 1999e). Time-
concentration plots for arsenic, manganese, molybdenum, selenium, uranium, and vanadium at
selected surface-water and ground-water locations are presented in Appendix E. Surface-water
and ground-water sampling locations nearest to the eastern boundary of the Millsite were favored
for representation because those are the locations where changes in water quality due to Millsite
activities are expected to be seen first. Contaminants were chosen for illustration on time-
concentration plots and plume maps on the basis of their distribution above detection limits.
Stream discharge measurements, ground-water levels, and water level hydrographs are presented
in Appendix F.
Because during the fall, Montemma Creek exhibits base flow conditions, water levels in the
alluvial system are generally the lowest, and contaminant levels are generally the highest in both
surface water and ground water, the October sampling round was designed to be the most
extensive. During October 1999,35 ground water samples and 10 surface-water sampIes were
collected. Water levels were measured at all existing wells and stream flow discharge was
measured at all surface-water locations sampled.
During January 2000, 15 ground water samples and four surface-water samples were collected.
Water levels were measured at all existing wells; stream flow discharge measurements were not
made.
DOWGrand lunclion Office OU IIt IRA Progress Reporl
September ZOO0 4-1
Monitoring and Additional Data Collection Document Number QO0.19700
The April sampling event was designed to compliment the October sampling event. During the
spring, Montezuma Creek exhibits high-flow conditions, water levels in the alluvial aquifer are
~ -
generally the highest, and contaminant levels are generally lowest in both surface water and
ground water. Data from the April sampling event is expected to show the low end of the range
of concentrations at each location. During April 2000,23 ground water samples and 10 surface-
water samples were collected. Four of the surface-water sanpling locations (SWOWI through
SW00-04) were new sampling locations and were selected by DOE, EPA and UDEQ as
permanent sampling locations. Location SW00-01 replaces SW99-01, SW00-03 replaces
SW92-06, and SWO0-04 replaces SW99-04. SW00-02 is a new site at the eastern boundary of
the former Millsite. Two of the surface-water samples were collected from seeps (seeps 4307 and
5215) in the southeastern part of the Millsite. Water levels were measured at all existing wells
and stream flow discharge was measured at all surface-water locations sampled.
During July 2000, five surface-water samples, one seep sample, and 24 ground water samples
were collected. Five of the ground water locations were additions to the routine sampling
locations and were added as part of an investigation to determine the source of contamination at
seeps 4307 and 5215. These five ground water samples were collected at 3 1SW93-197-2
through 31SW93-197-5, and AEC-6 (Figure 4.1-1). Water levels were measured at all existing
wells and stream flow discharge was measured at all surface-water locations sampled.
4.1.1 Surface Water Results
In surface-water, concentrations of arsenic, manganese, molybdenum, selenium, uranium, and
vanadium at SWOO-O1 near the western end of the Millsite were comparable to background
concentrations measured at location SW92-03 (see Figure 4.1.1-1).
Downstream of the Millsite, arsenic is generally not present in Montezuma Creek surface-water
samples at detectable concentrations (see Figure 4.1.1-1). Arsenic was occasionally detected at
concentrations less than 2 micrograms per liter (pg/L). The most stringent Utah surface-water
standard for arsenic is 50 pg/L based on domestic use.
Manganese concentrations downstream of theMillsite are approximately two to three times
background concentrations. East of the Sorenson site, concentrations of manganese tend to
increase to approximately one-half the Burro Canyon ground water concentrations and remain at
these levels throughout the eastern portion of the surface-water monitoring network. Discharge
of Burro Canyon ground water to the alluvial ground water and.to surface water is believed to be
the cause of the increase in manganese concentrations. Manganese concentrations fluctuate
widely in surface water east of the Millsite and have not shown any significant decreasing trends
since either Millsite seep discharge to surface water was eliminated after the October 1994
sampling event or due to excavation activities.
OU 111 IRA Progrcss Reporf WElGrand Junction OTficc
4 -2 Scptcmber 2000
Monitoring and Additional Data Collection Document Number Q0019700
Figure 4.1-1. Ground Water and Surface Water Monitoring Nefwok-West':
OU ti1 IRA Progress Report
4-3
.. ."V"
SCALE IN FEET
700 1400 2100 700 350 0
EB=z= U.S DEPARwCN& (RWO OaNERGY
WD mcnw C~ERMO
OU Ill DATA COLLECTION
MONITQRING LOCATIONS-
WEST
DAE WARD
M:\MSC\O35\0011\01\QO02l6AA.DWO 09/22/00 09:S7am 550181
FILENAME:
SEPTEMBER 22, 2000 Q00216AA
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Monitoring and Additional Data Collection Document Number QOOI 9700
Figure 4.1-2. Ground Water and Surface Water Monitoring Network-East
DOVGrand Junction Ofliw OU 111 IRA Progress Report
4-5 Se~lenlber 2WO
+ N10000
0 8 k
W
.. .
I __-_----
I -. ,x.. ! '.. I I '+ I + / + i- \ + N 7000
0 - I I 0 I 5: I \ rl "I \ . W
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\ L I EXPIANATION .. '. -. . I NLW GRWNOWAm LEEL + ~600 l4 +- WO CHorlS1.V NoftiTORlNO wEu
WCOS SWE GRWNDWATER + *NO WISTW HONllORlHO wEu 0 0 0 LOWR OMGTA UWOSlMIE WSR Lea WO O1EUISTRY MWllOFdNG WN 8
A BURRO WON LaUFUI WTER i W Lea lYiO MEIAnTR1 HoftIIO*NG WN : g .tn * nu smr/w now ma WAlU CHElllSlRY 0 0 0 \n
0 0
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I SCALE IN FEET 0 700 1400 2100
I
M:\M3C\O35\Wll\Ol\QOO217AA.DWG 09/05/00 4:llpm J50181
- U.S. DE&RW&N& OGNERGY
CRU(D mcrm wu,im
OU Ill DATA COLLECTION
MONITORING LOCATIONS -
EAST
OAE PREPAREO:
SEPTEMBER 5, 2000
FILENAME:
00021 7AA
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Monitoring and Additional Data Colleetio~l Document Nuniber Q0019700
-ExEwmL
mz-ca a SURFACE WATW HONlTDRlNO LOCATIONS
(ML RESULTS m rgN1
I I- U.S. Dg'&RTM&N& O&NEROY
aUHD wom*l mcrwo
Figure 4.1.1-1. Surface Water Sample Results
WWGrand Junction Office OU Ill IRA Progress Repon 4-7
Se~lsmber 20W
a SCALE IN FEET 0 1400 2800 4200 1400 700
OU Ill INTERIM REMEDIAL ACTION OCTOBER 1999, APRIL AND JULY 2000
SURFACE WATER SAMPLE RESULTS
WLTE PREPAREO:
~:\MSG\O35\oOll\01\Q00219AA DW 0s/25/00 10.63nm J50191
nmwn
SEPTEMBER 25. 2000 Q00219AA
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Document Number Q0019700 Monitoring and Additional Data Collcctio~~
Molybdenum concentrations downstream of the Millsite are approximately equivalent to
background concentrations at SW0&02 and SW00-03 sampling locations located nearest the
Millsite. East of SW00-03, concentrations of molybdenum increase to approximately two to
three times background and remain at this level throughout the eastern portion of the surface-
water monitoring network (see Figure 4.1.1-1). Discharge of contaminated alluvial ground water
to surface water is believed to be the cause of the increase in molybdenum concentrations.
Overall, molybdenum concentrations have continued to decrease in surface water east of the
Millsite since Millsite seep discharge to surface water was eliminated after the October 1994
sampling event; the decrease in molybdenum is also attributed to the positive effect of source
removal at the Millsite and downstream along Montezuma creek.
Selenium concentrations ranged from non-detect to 9.7 pg/L at locations downstream of the
Millsite. In April 2000, selenium concentrations at seeps 4307 and 5215 were 161 pgiL and
16.7 pa, respectively. Selenium has shown a tendency of increasing concentrations in surface
water during the last year, which may be due to leaching of exposed bedrock on the Millsite. At
the Sorenson site, selenium concentrations have doubled during the last year and were 8.4 pg/L
and 9.7 pg/L in April and July 2000, respectively. In upstream (background) surface-water
samples, selenium is generally not detected. The Utah criterion for protection of aquatic wildlife
based on a four-day average sample is 5 pg/L.
As shown by the April 2000 data, uranium concentrations progressively increase.fiom
background levels at SW00-01 on the western edge of the Millsite to an approximate maximum
concentration of 162 pg/L at the Sorenson site east of the Millsite as measured in July 2000
(Figure 4.1.1-1). East of this location, uranium concentrations either remain the same or
decrease slightly at all other locations in the monitoring network. Uranium concentrations have
continued to decrease in surface-water east of the Millsite since seep discharge to surface water
was eliminated after the October 1994 sampling event. Changes during the last year are probably
also due to the positive effects of Millsite remediation. The highest uranium concentrations were
measured at seeps 4307 and 5215 (see Section 4.2.7, Figure 4.2.7-1) on the Millsite in April
2000 (1,480 pg/L and 824 pg/L, respectively). The high concentration of uranium was
confirmed at seep 5215 in July 2000 (1,160 pg/L). The investigation of the source of uranium for
seeps 4307 and 5215 has been referred to as the "Deer Draw" investigation because of the
proximity of Deer Draw to the seeps. The status of the Deer Draw investigation is discussed in
Section 4.2.7.
Vanadium is generally not detected in surface-water samples collected east of and on the
Millsite. The maximum vanadium concentration of 6.4 pg/L was measured at SW92-06 in April
2000. Overall, vanadium concentrations have decreased substantially in surface water east of the
Millsite since seep discharge to surface water was eliminated after the October 1994 sampling
event. Recent declines in the vanadium concentration may be due to source removal activities on
and off the Millsite.
DOWGrand Junction Oflice OU Ill IRA Progres Report
September 2000 4-9
lvlonitoring and Additional Data Collection Document Number Q0019700
4.1.2 Ground Water Results
Since tailings removal began in about April 1997 ground-water monitoring on the Millsite has
been reduced to a few temporary wells along its northern margin and in the southwest comer.
During the period reported in this progress report (July 1999 to July 2000), much of the alluvial
aquifer on the Millsite remains dewatered and excavated to bedrock. The aquifer has yet to be
reconstructed. Sample results from the temporary wells along the northem margin indicate that
concentrations of some contaminants exceed background levels. The extent of contaminated
ground water in this area is thought to be small. Alluvial ground water in the southwest comer of
the Millsite (well 82-20) is not contaminated. Figures 4.1.2-1 through 4.1.2-7 illustrate the
ground-water sampling locations and results for arsenic, manganese, molybdenum, nitrate,
selenium, uranium, and vanadium from October 1999, April 2000, and July 2000. Alluvial and
bedrock ground-water quality data is presented in Appendix D.
New downgradient wells continue to be added to the sampling network to improve the definition
of the downgradient contaminant plume. Installation of new monitoring wells is summarized in
Sections 4.2.3 and 4.2.4. In general, contaminant concentrations in the alluvial aquifer are about
the same as before the Millsite was remediated. However, for some wells close to the Millsite
(92-1 1,92-07, and 88-85 for some contaminants) there is a trend towards decreasing
concentrations duling the last year. Selenium is the only COC identified in the RI that has shown
a trend of increasing concentrations. The trend is most notable at wells 92-1 1 and 88-85 closest
to the Millsite. Plots of concentration versus time for several wells are included in Appendix E.
Since October 1998, ground water samples collected from wells just east of the Millsite have
shown large increases in nitrate, from about 5,000 pg/L or less to between 15,000 and
35,000 pg/L (reported as equivalent nitrogen [N]). The MCL for nitrate (as N) is 10,000 pg/L.
No such impact has occurred in surface water. Nitrate results since November 1992 for the
effected wells (92-1 1,92-07, and 88-85) are shown in Figure 4.1.2-8. Farther downgradient,
the increases have been much smaller and the MCL has not been exceeded (Figure 4.1.2-8).
Among the July 2000 sample results, the maximum nitrate concentration (55,100 yg/L) occurred
in the sample collected from well MW00-08A, located on the eastern boundary of the Millsite
(see Section 4.2.3, Figure 4.2.3-1). However, the levels of COCs in the same sample were low
relative to typical concentrations from wells in that area prior to tailings renloval. Samples
collected from the two wells at the western edge of the Millsite (MW00-01 and MW00-02;
see Section 4.2.3, Figure 4.2.3-1) contained about 900 and 400 yg/L nitrate as N, consistent with
historical values at 92-05 located west of the highway. Nitrate in ground water beneath the
eastern portion of the Millsite prior to surface remediation was typically about 2,000 to 7,000
pg/L. The data indicate a nitrate source on or along the north and south margins of the Millsite
that was absent or isolated prior to tailings removal. The nitrate pulse appears not to be an effect
of contaminant mobilization during tailings excavation, or any activity or land use east of the
Millsite.
OU Ill IRA Progress Report DOWGrand lunclion Office
4-10 September 2000
Document Number Q0019700 Monitoringand Additional Dafa Collectio~~
UWWAL #4m IRUNmr UGIMYS
EXPLANATION
88-85 ALLUVIAL GROUNDWATER MONITORING WELL
*S OCTOBER 1999 DATA
J18 APRIL 2000 DATA 1. PeRT WALL INSTALLATION COMPLETED IN JULY 1999. : 2i4 JULY 2000 DATA
2. ARSENIC CONCENTRATION DOES NOT EXCEED qt TEMPORARY MONITORING WELL ARAR-BASED PRELIMINARY REMEDIATION GOAL
(50/.6g/L] AT ANY LOCATION. - " - MILLSITE BOUNDARY
-c- APPROXIMATE EXTENT OF ALLUVlAL AQUIFER
SCALE IN FEET
Figure 4.1.2-1. Ground Water Sample Results-Arsenic
WWGrand Junuion Olfice OU Ill IRA ProFern Repon
4-11 Seplcmber 2000
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Document Number Q0019700 Monitoring and Additional Data Collection
MUN/CyrAL mm
rnlWNTL4~
EXPLANATION
ALLUVIAL GROUNDWATER MONITORING WELL saw
MANGANESE CONCENTRATION IN GROUNDWATER,
Id-
360 . OCTOBER 1999 DATA
1. PeRT WALL INSTALLATION COMPLETED 155 APRIL 2000 DATA
IN JULY 1999, 68.6 JULY 2000 DATA
2. MANGANESE CONCENTRATION EXCEEDED THE
SUGGESTED PRELIMINARY REMEDIATION GOAL 4 TEMPORARY MONITORING WELL
(730/1g/L) AT LOCATIONS 92-8, 92-1 1,
R10-MI IN OCTOBER 1999, GB1126, 92-11, ----
R8-MI. R9-MI, R10-MI IN APRIL 2000, AND MILLSITE BOUNDARY
92-1 1, MWOO-94 AND MW00-08 IN J,ULY 2000. -- APPROXIMATE EXTENT OF ALLUVIAL AQUIFER
SCALE IN FEET OU Ill INTERN REMEDIAL ACTION
800 400 0 800 1600 2400 OCTOBER 1999, APRIL AND JULY 2000
GROUNDWATER SAMPLE RESULTS-MANGANESE
OAK PREPARED: FILENAMEi
M:\MsG\035\O011\Ol\OO0211AAADW 08/26/00 10:37am d.50181 SEPTEMBER 25, 2000 Q00211AA
Figure 4.1.2-2. Ground Wafer Sample Resulfs-Manganese
WWGrand klxclion Office ou Ill IRA Pmgnss %pwt
4-13 Scptcmber 2000
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Monitoring and Additional Data Collectio~i Document Number Q0019700
U~CPAL mawm mm urn
88-83 ALLUVIAL GROUNDWATER MONITORING WELL
5~4 OCTOB~R 1.989 DATA
1. PeRT WALL INSTALLATION COMPLETED 37.5 APRIL 2000 DATA
IN JULY 1999. 43.1 JULY Z@@0 MTA
2. MOLYBOENUM CONCENTRATION EXCEEDED THE TEMPORARY MONITORING WELL
SUGGESTED PRELIMINARY REMEOlATlON GOAL
(100fig/L) AT LOCATIONS 92-1 1 IN OCTOBER ---- MILLSITE BOUNDARY 1999, GB1126, PW-17 IN APRIL 2000, AN0
MW00-04, MW00-08 IN JULY 2000. -- APPROXIMATE EXTENT OF ALLUVIAL AQUIFER
SCALE IN FEET
800 400 0 800 1.600 2400
Figure 4. f.2-3. Ground Wafer Sample Results-Molybdenum
OU Ill IRA Progress Reprt DOElOrand Junction Office &IS
September 20W
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Document Number Q0019700 Monitoring and Additional Data Collection
UWAL WNP . . 7RmRIEMum
EXPLANATION
ALLUVIAL GROUNDWATER MONITORING WELL 8&85
NOJ fN4 AS N CONCENTRATION IN GROUNDWATER,
rn9/'-,
NOTES:
1. PeRT WALL INSTALLATION COMPLETED
IN JULY 1999.
EX5 OCTOBER 1999 DATA
3.4 APRIL 2000 DATA
2 3 dULY 2Wp DATA
2. NITRATE CONCENTRATION EXCEEDED THE
ARAR-BASED PRELIMINARY REMEDIATION GOAL + TEMPORARY MONITORING WELL
(lorn /L) AT LOCATIONS P92-09, 92-1 1. 88-61, 92-07 AND P92-06 IN OCTOBER 1999 92-1 1, 88-65, 92-07 AND ~92-06 IN APRIL iooo, - MILLSITE BOUNDARY
AND MWOO-08, 92-1 1, 88-85, 92-07, T99-01 AND P92-06 IN JULY 2000. --c- APPROXIMATE EXTENT OF ALLUVIAL AQUIFER
Figure 4.1.2-4. Ground Wafer Sample Results-Nitrafe
WUOTand Junction OEee OU Ill IRA Progress Report
4-17 September 2000
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Document Number Q0019700 Monitoring and Additional Data Collection
---- ----
MLMCPAL WAm 7RUlmuOWNS
--
EXPLANATION
w.ffi ALLUVIAL GROUNDWATER MONITORING WELL
SELENIUM CONCENTRATION IN GROUNDWATER,
/Jg/L
32.9 OCTOB'ER 1999 DATA
1. PeRT WALL INSTALLATION COMPLETED 87 APRIL 2000 DATA
IN JULY 1999. 3.2 JULY 2000 DkTA
+ TEMPOWY MONITORING WELL ---- MILLSITE BOUNDARY
/-
SELENIUM CONCENTRATION EXCEEDS
SCALE IN FEET OU Ill INTERIM REMEDIAL ACTION
800 400 0 800 1600 24bv OCTOBER 1999, APRIL AND JULY 2000
GROUNDWATER SAMPLE RESULTS - SELENIUM
OAK PREPMKO: FILENUIE:
M:\MsC\035\0011\01\90021JAA.0~ 09/25/00 !0:08om 450191 SEPTEMBER 25, 2000 400213AA
Figure 4.1.2-5. Ground Wafer Sample Results-Selenium
WEJGrand Junction Ollicc OU Ill IRA Progress Reporl
September 2OW 4-19
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Monitoring and Additional Data Collection Document Number Q0019700
MUNlCiPAl HYmP ~IUENTU~
EXPLANATION
ALLUVIAL GROUNDWATER MONITORING WELL m-e.5
URANIUM CONCENTRATION IN GROUNDWATER,
@9/L
562 OCTOBER 1999 DATA
1. PERT WALL INSTALLATION COMPLETED 539 APRIL 2000. DATA
IN JULY 1999. IlH m3L @3@ ,WIrki
+~ TEMPORARY MONITORING WELL -..- MILLSITE BOUNDARY -- APPROXIMATE EXTENT OF ALLUVIAL AQUIFER
DOUGnnd Junction Olfue
September 2033
Figure 4.1.2-8. Ground Water Sample Resulfs-Uranium
OU Ill IRA Progress Repon
4-21
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Document Number Q0019700 Monitoring and Additional Data Collection
1. PeRT WALL INSTALLATION COMPLETED
IN JULY 1999.
304 APRIL 2000 DATA
146 JULY 2000 DATA
4- TEMPORARY MONITORING WELL ---- MILLSITE BOUNDARY
+ N aooo
I I
+- APPROXIMATE EXTENT OF ALLUVlAL AQUIFER I I
I \
VANADIUM CONCENTRATION EXCEEDS \
SUGGESTED PRELIMINARY REMEDIATION 1
GOAL (260pg/L) \ \ \ I
.Ram= U.S. QEaRWwW& OGNERCY
w IUUO~ mw
SCALE IN FEET OU Ill INTERIM REMEDIAL ACTION
0 800 1600 2400 OCTOBER 1999, APRIL AND JULY 2000 800 400 GROUNDWATER SAMPLE RESULTS - VANADIUM
DATE PREPARED: FILENAME:
M:\MSG\OJS\OOll\ol\Qw2lSAA,DW 09/22/00 1: 14pm J30191 SEPTEMBER 22. 2000 Q00215A1
Figure 4.1.2-7. Ground Water Sample Results-Vanadium
DOWGrand Junction Ollice
Scplember 2000
OU Ill IRA Progress Repon
4-23
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Document Number Q0019700 Monitoring and Additional Data Collection
4.2. Data Collection
This section reports the status of data collection tasks to characterize conditions on the former
Millsite that affect surface water, and ground water. The task status updates information
presented in the August 1999 status report (DOE 19990. Additional data interpretation is also
provided.
4.2.1 Distribution of Metal COCs in Vadose Zone Soil
Soil samples were collected at 238 locations to characterize the distribution of COC metals in the
upper six inches of the remediated surface on the Millsite. Another 64 samples were collected
from the upper six-inch interval in areas that were remediated to bedrock. At 125 other locations,
surface samples (I 15 soil and 10 rock) were collected for analysis of uranium and thorium to
satisfy OU I verification objectives. Those uranium results are included in the discussions that
follow. Surface soil sampling was completed in fall 1999.
. .
As remediation of the Millsite proceeded, data from surface and subsurface soil samples and
column leach tests (Section 4.2.2) was used to guide soil removal beyond the depth of
radiological contamination. The additional soil removed has been loosely referred to as "residual
vadose zone" (RVZ), although in many areas of the Millsite the soil would be saturated if the
alluvial aquifer was restored. This resulted in the removal of a 2-A. layer beneath areas of each
pile and a 4-ft layer along the toe of the Vanadium Pile. Soil samples from those intervals are not
included in the final characterization results presented in this report. The new surface was not re-
sampled in some areas after the additional soil was removed.
At 56 of the surface locations, a sample was also collected from the 2 - 3 ft depth interval;
additional depth sampling up to 7 ft below the remediated surface was completed at 20 of those
56 locations. The depth samples did not include bedrock material. Depth intervals presented in
this report have been adjusted to account for soil removal after sample collection. For example,
samples collected 2 - 3 ft below the original verified surface, prior to removing an additional 2-ft
layer, are presented as surface samples. Subsurface sampling was completed in winter 1999.
Surface Sanrple Results
Sample locations and results for the final remediated surface (0 - 6-inch depth interval) are
shown in Plates 1 to 3 for arsenic, uranium, and vanadium, respectively. These elements are the
primary components of risk due to consumption of ground water in OU 111. Also shown are areas
where soil was removed below the depth of radiological contamination ("RVZ" removal areas)
and areas where soil removal extended to bedrock. The actual area of exposed bedrock is greater
than appears in Plates 1 to 3. The maps will be updated after field mapping is completed during
fall 2000. Laboratory results for the surface soil samples are tabulated in Appendix G-1.
Summary statistics and frequency distributions for arsenic, uranium, and vanadium results are
shown in Table 4.2.1-1 and Figures 4.2.1-1 to 4.2.1-3.
DOfYGntrd Junction Office OU Ill IRA Progress Report
September 2000 4-27
Monitoring and Additional Data CoUffition Document Number QOOl9700
Table 4.2.1-1. Summary of Surface Sample Resulfs
Figure 4.2.1-1. Arsenb Concentrations in Surface Soils
Figure 4.2.1-2. Uranium Concenfrafions in Surface Soils
OU In IRA Progress Repart DOEIGrad Jvnctiun OKI*
4-28 September 2000
DomunentNumber Q0019700 Monitoring and AdditionnlDnta Collection
Figure 4.2.1-3. Vanadium Concenfrafions in Surfam Solls
Arsenic concentrations in the upper six inches of soil and bedrock are narrowly distributed about
a mean of about 10 mglkg. Mean concentrations and deviation %bm the mean among bedrock
and soil sample groups are very similar. Arsenic concentrations in about 50 percent of both soil
and bedrock samples are < 10 mg/kg, and 95 percent of the samples are 1; 15 mgkg. In nap view,
arsenic concentrations beneath the former Acid Pile appear to be slightly less than beneath the
Carbonate, Vanadium, and East Piles (Plate 1).
The average concentration ofuranium in bedrock samples is greater than in the soil samples. The
bedrock results also exhibit a wider positive deviation from the bedrock mean (15.5 pCi/g).
These probably result from the frequency of outlier values among the bedrock samples.
In map view, the higher concentrations are associated with two bedrock areas northwest of the
former Carbonate Pile, and in the bedrock area of the East Pile (Plate 2). The soil sample data
indicate a narrow distribution about the mean of 7 pCi/g. Uranium concentrations in about 95
percent of the soil samples are ~15 pCjlg.
Average concentrations of vanadium are similar between soil and bedrock sample groups.
Bedrock and soil samples also display a similarly narrow distribution about the respective means,
About 90 to 95 percent of all samples contain less than 75 mglkg vanadium. The higher outlier
samoles tend to be associated with the central and southern pottions of the Carbonate and
~ankdium piles (Plate 3).
Depth Sampie RanIts
Depth-sample location information is summarized in Table 4.2.1-2. All depths are relative to the
final remediated surface. Some depth samples were collected prior to the removal of soil below
the depth of radiological contamination, Safnples collected from the removed intervals are not
included in the table or in the characterization results presented in this report. Deeper samples
DOEKimnd Junction Office OU Ill IRAProgrcss Report
September 2000 4-29
Monitoring and Additional Data Collection Document Number Q0019700
have been adjusted up accordingly. For example, the grid 3051 sample was originally collected
at a depth of 6 to 7 feet. Subsequent soil removal to 4 feet below the depth of radiological
contamination occurred in the area including grid 3051 and so the sample interval is reported as
2 to 3 feet below the final remediated surface. Laboratory results for the depth samples are
included in Appendix G-2. Summary statistics for the depth samples are provided in
Table 4.2.1-3.
Table 4.2.1-2. Depth Samples
Sample means for arsenic (Table 4.2.1-3) suggest a slight increase in concentration with depth.
Figure 4.2.1-4 reveals however, that the averages are biased by one or two outliers, and that
concentrations may not vary or decrease with depth. Each point on tlte plot (and on
Figures 4.2.1-5 and 4.2.1-6) represents a sample from the respective depth interval. Grid 2409
had the maximum arsenic concentrations for each interval below 12 inches. Except for those
points, arsenic concentrations appear to be natrowly distributed about the means. On average,
uranium concentrations in the depth samples are less than surface samples. The concentrations
also exhibit less variability with depth (Figure 4.2.1-5). The results suggest that less uranium is
present at depth, relative to the surface soil. Vanadium concentrations range widely in the zero to
12 and 24 to 36-inch depth intervals, where the means are 39 and 52 mg/kg, respectively. In the
lower depths, vanadium concentrations are less variable about means of 45 and 33 mg/kg.
Vanadium results are plotted against sample depth intetval in Figure 4.2.1-6.
OU If1 IRA Progress Report DOWGrand Junction Office
4-30 September 2000
Table 4.2.1-3. Summary Statistics for Depth Soil Samples
Monitoring and Additional Data Collection Document Numbe~ 40019700
Arsenic Depth Profile
12 24 36 48 60 72 8a
Center of Depth Interval Fnches]
Figure 4.2.1-4. Arsenic Depth Profile
Uranium Depth Profile
12 24 36 48 60 72 84
Center of Depth Interval [inches]
Figure 4.2.1-5. Uranium Depth Profiie
OU In IRAPmgress Report DOWOraud hnction Offiw
4-32 Sapteuhr ZOO0
Document Number QOO 19700 Monitoring and Additional Data Collection
Vanadium Depth Profile
Center of Depth Interval [inches]
Figure 4.2.1-6. Vanadium Depth Profile
4.2.2 Characterize Mobility of COCs in Vadose Zone
Column leach testing was performed to determine if post-remediation soil was a potential source
of ground water contamination. Soil samples used in the column tests were collected from sub-
vile areas that had been remediated to a radiological standard (Ra-226). Leaching of arsenic,
branium, and vanadium was evaluated. The collmn testing was compieted in MG 2000.
'
Summary of Padose Zone Column TNs
Twenty-two column experiments were performed at the Environmental Sciences Laboratory
(ESL) at theDOE Grand Junction Office. Columns were run with three fluid compositions
(synthetic) to simulate different waters that might leach unsaturated zone soil in future scenarios,
which are: infiltration of precipitation (12 complete tests, 1 partial test), a rising ground water
table (5 complete tests, 1 partial test), and infiltration of irrigation water containing components
of fertilizer (3 complete tests). Six tests were originally planned to evaluate the effect of fertilizer
on leaching, however three tests were omitted after it was learned that the former Millsite would
not be restored as a golf course. Conditions of each column test are summarized in Table 4.2.2-1.
Pertinent details regarding the objectives, scope, and design of the study are presented in the
Interim Remedial Action Work Plan for Operable Unit III (DOE 1999g). The ESL has prepared a
report that further describes the methods used and results of the leaching studies (DOE 2000).
DOPIGrand Junction O5ce ou ln IRA ~rogress ~epmt
September 2000 4-33
Motiitoring and Additional Data Collection Document Number Q0019700
Table 4.2.2-1 Vadose Zone Column Conditions
Not including bromide tracer experiments.
b~uspect measurement, leaky &lumn with flow blockage: test aborted.
The soil samples and column tests are identified by their respective grid block within the OU I
verification grid (Figure 4.2.2-1) and fluid composition. Some samples were composites of
several locations within a grid block. Discrete depth intervals up to 5 ft below the remediated
surface were sampled. Most samples consisted of fine sandy silt, with some clay and occasional
gravel. The samples from grids 3287 and 3164 were composed of sand and gravel with few fines.
At the ESL, the samples were dried then manually disaggregated. The occasional gravel in the
fine-grained samples was handpicked and removed. Coarse gravel (>0.75 in.) and cobbles were
removed in the field for samples 3287 and 3164, which accounted for about 25 percent of the
original volume. Soils used in the tests were first analyzed at the GJO Analytical Chemistry
Laboratory (ACL) for arsenic, uranium, and vanadium. Analytical results for the soils are shown
in Table 4.2.2-2.
OU 111 IRA Progress Report DOWGrand Juactioa Office
4-34 September 2000
Figure 4.2.2-1. Locations of Soil Samples Used in Column Testing
Monitoring and Additional Data Collection Document Number Q0019700
Table 4.2.2-2 Concentrations of Arsenic, Uranium and Vanadium in Soils Before Column Testing
During the leaching portion of the experiments, concentrations of uranium, pH, electrical
conductivity, oxidation-reduction potential, and alkalinity were measured in the ESL soon after
sample collection. Samples were collected at a minimum frequency of one per pore volume
(about every 12 hours). The columns were run for at least 10 pore volumes. To observe longer-
term concentration levels, some columns were run for up to 29 pore volumes. Effluent samples
were collected and submitted to the GJO ACL for analysis of arsenic, uranium, vanadium, and
major inorganic ions.
Flow to the columns was interrupted in six tests for prolonged periods to determine if a rate-
limiting step was evident in the leaching process. In addition, bromide tracer experiments were
conducted to estimate dispersivity coefficients in the columns. The results of the leaching tests
will be used along with geohydrologic modeling to estimate the impact these soils may have on
contamination to the underlying aquifer. Some of the early results of the ESL column
experiments were used to identify areas in which additional (nonradiologic) soils were removed
to help meet ground-water quality standards.
Vadose Zone Colurnn Test Results-Uranium
The results of 13 baseline mobility tests for uranium are illustrated in Figure 4.2.2-2. The
influent, called "Loyd's Lake" water, was simulated from the composition of samples collected
from OU 111 location SW92-01, on South Creek near the outflow from Loyd's Lake. The
composition is intended to represent irrigation water or precipitation that contacts the subpile
soil.
OU 111 IRA Progress Report DOEIGrand Junction Ofice
4-36 September 2000
Document Number Q0019700 Monitoring and Additional Data Collection
The graphs clearly show that leachable uranium is present in soil with uranium concentrations
greater than about 5 pCi/g. Columns 3417 and 2919 did not leach uranium. The concentration of
uranium in those samples was about 3 pCi/g, which is consistent with background levels in
OU I1 reference area soil samples. The column test results show good agreement between initial
soil concentration and effluent concentration. Uranium concentrations in about 60 percent of
subpile surface samples were greater than 5 pCi/g. About 30 to 35 percent of the depth samples
exceeded 5pCiIg uranium. These results suggest that leachable uranium'is present throughout the
depth intervals sampled; however, the amount apparently decreases with depth.
Maximum uranium concentrations in the effluent ranged from about 0.5 to 3.5 parts per million
@pm) (500 to 3,500 pg/L or parts per billion [ppb]). Peak concentrations typically occurred after
several pore volumes had passed. The cause of this is not known but may be related to
preferential flow in the early stages of the experiments. A period of relatively rapid flushing
through several or more pore volumes then occurs until levels reach between about 0.25 and
0.5 ppm. In the later stages of the experiments effluent concentrations decrease much more
gradually. Persistent tails appear to converge to levels on the order of 100 to several hundred
ppb. Complete leaching of uranium did not occur in any test. Normalizing the column test
conditions to a 1-meter thick subpile layer, the flushing period is about 6 years per pore volume
assuming 25 percent porosity and 4 cm recharge annually (equivalent to 10 percent of annual
precipitation). Under these assumptions, the 5 to 10 column test pore volumes required to flush
most of the uranium from the soil is equivalent to 30 to 60 calendar years.
Flow to five columns was temporarily interrupted for periods ranging behveen 55 and 97 hours.
This was done to determine if concentrations would rebound to a higher level after flow was
resumed. Significant rebounding would be a qualitative indication of a rate limiting step in the
leaching process. The periods of flow interruption are shown in Figure 4.2.2-2. A rebound is
seen in each instance. Except in column 4849 however, the effect is mild relative to the
concentrations during the early part of the tests. This would indicate that to some degree the
effluent (or soil water) concentration could be a function of the flow rate through the medium. In
the vadose zone, where flow rates are expected to be much lower, concentrations may therefore
persist at the higher levels observed in the columns.
Uranium leaching was not observed to be very sensitive to fluid composition. In Table 4.2.2-1
and Figure 4.2.2-3, the fluid called "Ground water" was simulated from OU I11 sample results at
well 92-05, which is upgradient of the former Millsite. The solution is slightly acidic (pH = 6.7)
but is otherwise similar to the composition of Loyd's Lake water (pH = 7.8). For a given sample,
the curves shown in Figure 4.2.2-3 essentially overlap. The results of the "Golf Course" leach
(Table 4.2.2-1 and Figure 4.2.2-4) suggests that the fertilizer components either have no effect
or reduce uranium mobility.
In summary, the results indicate that uranium is readily mobilized under the column test
conditions. By extrapolation, the sub-pile vadose zone represents a source of contamination to
ground water for a relatively long period if leached by ground water, irrigation water, or
precipitation. However, the impact on ground-water quality depends on the infiltration rate,
thickness and area of the subpile layer, and volumetric flux of the ground water beneath the
source, in addition to source concentration and contaminant mobility.
OOWGrand Junction Office OU 111 IRA Progress Report
September 2000 4-37
Monitoring and Additional Data Collection Document Number Q0019700
Vadose Zone Column Test Resulls-Arsenic
Arsenic desorption curves using Loyd's Lake water are shown in Figure 4.2.2-5. The most
significant leaching occurred in column 3051, where the initial soil concentration (35 mglkg)
was about triple that in the other columns. The peak concentration in the column 3051 test was
43 ppb. Arsenic concentrations in many of the effluent samples of the remaining tests were less
than or only slightly above the limits of detection. The peak concentration among those tests was
14 ppb (column 2618). In the columns with leachable arsenic (i.e., columns 3051,2618, and
2153), early peaks are followed by relatively flat tails at about one-half the concentration of the
peak value. Neither rapid nor complete leaching of these samples occurred.
With the exception of sample 3287, arsenic c6ncentrations were consistently greater in the
effluent of the acidic leach (Figure 4.2.2-6, "Ground Water" leach) than in the Loyd's Lake
effluent. Arsenic concentrations in the effluent of both 3287 tests were near or below detection
limits. Although arsenic mobility appears to be favored by mildly acidic conditions, the resulting
concentrations remained relatively low. The results of the "Golf Course" leach (Figure 4.2.2-7)
suggests that fertilizer components may reduce the mobility of arsenic. The effect of interrupting
flow was very subtle or absent.
Arsenic concentrations in about 90 to 95 percent of surface and depth samples were 1: 15 mgkg.
Averages for surface samples and in discrete depth intervals are about 10 to 12 mg/kg, excluding
several anomalous depth samples. The column soils, except 3051, contained arsenic between 9.3
and 13.6 mgkg. Arsenic leaching from those columns was minor or absent. The subpile soil is
not likely an important source of arsenic contamination to ground water
Vadose Zone Column Test Results-Vanadium
Vanadium desorption curves for the Loyd's Lake fluid are shown in Figures 4.2.2-8 and 4.2.2-9.
The most significant leaching occurred from sample 3051, which also had the highest initial soil
concentration (408 mgkg). The graphs show that leachable vanadium is present when soil
concentrations exceed about 60 mag. Desorption was not rapid or complete in these tests
(columns 3071,2618, and 3051). The vanadium concentration in 90 to 95 percent of subpile
$amples (surface and'depth) was less than 60 mglkg. The maximum effluent concentration foi
column samples with less than 60 mg/kg was 18 ppb vanadium. Most results were near or less
than the limits of detection. Similar to the arsenic results, the mobility of vanadium may be
slightly greater in the acidic leach test and possibly less mobile in the Golf Course leach
(Figures 4.2.2-10 and 4.2.2-1 1). The data is not sufficient to evaluate the effect of interrupting
flow. Subpile soil is not likely to be a significant source of vanadium to the ground water.
OU 111 IRA Progress Report WWGrand Junction Office
4.38 September 2000
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0.05 4 MCL
ARSENIC DESORPTION FROM RVZ SOIL
LOYD's LAKE LEACH: ALL SAMPLES
lnnial Soil CMcenbadOn
column mgM Arsenic
--g- 5051 34.6 + 2.918 13.6
--b 37102 13.5
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Minlmum mk-based PRG (0 W5 mgh) _____--
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Efi'uent Pore Volumes
Figure 4.2.2-5. Arsenic Desorption From RVZ Soil-Loyd's Lake Leach All Samples
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Document Number Q0019700 Monitoring and Additional Data Collectiotl
4.2.3 Installation and Monitoring of Temporary Wells
Since the inception of tlie IRA, temporary wells for OU I11 plume monitoring have been installed
on four occasions: February, June, and October 1999, and April/May 2000. Temporary wells
installed as part of the Deer Draw investigation are discussed in Section 4.2.7. Borehole and well
data has been used to determine aquifer boundaries, to determine the extent of ground water
contamination in areas not previously characterized, and to guide placement of permanent wells
for long-term monitoring. Depth to bedrock, water level, and lithologic information has also been
obtained. Temporary wells were installed along the upgradient and downgradient ends of tlie
Millsite, on tlie Millsite, and in several north-south transects east of the Millsite and PeRT wall
(Figures 4.2.3-1 and 4.2.3-2). The majority of temporary wells planned for the Millsite could
not be installed because the site has not been sufficiently restored. Much of the area of interest
remains exposed to bedrock, and ground water capture and diversion remains in effect.
In February 1999, five temporary wells (GB1126T, GB1227T, GB1690T, GB2820T, and
GB3 127T) were completed in the northwestem and central northern areas of the Millsite.
Rationale for well placement and additional installation information is provided in the August
1999 Status Repoi-t (DOE 1999f). These wells have been monitored quarterly since February
1999. Only well GB1126T has routinely yielded enough water for sample collection although
only partial samples have been collected because of limited water and very slow recovery. Wells
GB1227T and GB1690T have always been dry. Partial samples have been collected periodically
at GB2820T and GB3127T. To facilitate Millsite restoration, and because of the poor well
performance, these wells were abandoned in August 2000. The data obtained f?om monitoring
these wells will be used to site permanent well installations following restoration.
Seven temporary wells were set in the Montezuma Creek valley east of the PeRT wall in June
1999. The wells were completed along three north-south transects, primarily on the south side of
Montezuma Creek, in alignment with other OU 111 monitoring wells. The wells have been
monitored quarterly since July 1999. Saturated alluvium was not encountered at locations
T99-06, T99-07, and T99-10 during drilling and the wells, which are screened to bedrock, have
since remained dry. Well T99-02 is typically dry or has very little water (also screened to
bedrock).
Well T99-03 contains enough water to collect a sample but it is very slow to recover. Wells
T99-01 and T99-05 routinely yield sufficient-water for sample collection. Refer to the August
1999 IRA Status Report (DOE 19990 for additional information regarding these wells.
Temporary wells T99-11, T99-12, and T99-13 were installed in October 1999. These wells
were installed primarily to optimize the location for a permanent well closer to the PeRT wall
than currently exists. Quarterly monitoring of these wells began in January 2000. Wells T99-12
and T99-13 have been dry since installation.
DOWGrand Junction Office OU I11 IRAProgress Report
Septeniber 2000 4-59
Monitoring and Additional Data Collection Document Nutnber Q0019700
Two lines of temporary wells were installed in ApriVMay 2000: 8 along the western boundary of
the Millsite, and seven along the eastern boundary of the Millsite (Figures 4.2.3-1 and 4.2.3-3).
These were installed to investigate bedrock topography and the extent of the aquifer toward the I
valley margins, and to select permanent well locations. The eastern line of temporary wells
remains incomplete north of the creek until the area is re-contoured to allow rig access. These
wells will only be monitored for water levels. Ground water pinches out to the north between
wells TOO-12 and TOO-1 1. Four to 5 feet of saturated alluvium are present in the center of the
valley at wells TOO-14 and TOO-15. Along the east boundary, 1 to 2 feet of ground water occurs
in the central part of the valley between wells TOO-01 and TOO-05. This area may be underlain
by fill that was placed after soil remediation. The extent of the aquifer farther north is not known.
Granular deposits (alluvium?) are present above bedrock south of T00-05, however they are
presently unsaturated. Ground-water levels in this area may be effected by continued ground-
water diversion to the west. These wells are scheduled to be surveyed during October 2000;
following survey, lithology and well completion diagrams will be prepared.
PeRT Performance Monitoring Wells
Temporary wells were installed in phases since September 1999 to monitor the hydraulic
performance of the PeRT wall. A large majority of those wells were completed in September and
October 1999. Surface remediation and site restorations precluded installing several wells until
January and February 2000. The final PeRT performance monitoring well was completed August
2,2000. Figure 4.2.3-3 shows the locations of the PeRT performance monitoring wells,
excluding those within the reactive media, which are shown in Figure 4.2.3-4. The PeRT wells
shown in these figures have been monitored concurrent with OU I11 quarterly events since
installation. The monitoring data is being used to evaluate the hydraulic performance of the gate I
and slurry walls and the effectiveness of the reactive media in reducing contaminant
concentrations. Water quality monitoring is conducted at each well in and immediately
surrounding the gate. Water levels are measured at each well. In addition, the creek stage at
several locations in the PeRT area has been measured during recent quarterly monitoring events.
Under the Monticello PeRT Wall Project, data collection activities were also implemented in
June and July for gate performance monitoring. Although these efforts are separate from OU I11
IRA tasks, they are relevant to OU I11 objectives and so are briefly described. In June, the
Geoprobe rig was used to place four 2-inch wells in the ZVI section of the gate. Six 2-inch wells
on the upgradient side of the gate and four 2-inch wells about 15 to 20 feet east (downgradient)
of the gate were installed by sonic drilling in July. Well TW-09 is completed in bedrock and is
paired with alluvial well TW-08. Depth to bedrock at TW-08/TW-09 is 12.5 ft below ground
surface.
Well TW-09 is screened from 14.2 to 19.2 ft below ground surface. The bedrock was dry to the
cored depth of 35 ft. After the new wells were developed, gas-displacement slug tests were
conducted in triplicate at ten alluvial wells and seven ZVI wells. A multi-species tracer test
through the gate was completed in July. Data analysis is in progress. Prior to the tracer tests, flow
conditions were evaluated at several wells using a downhole instrument, the colloidal borescope,
that tracks movement of suspended colloids (see Section 5.2 for more information). Additional
borescope tests are for the planned for the fall.
OU 111 IRA Progress Report DOWGrand lunction Olficc
4-60 September 2000
Docurnelit Number Q0019700 Monitoring and Additional Data Collectioti
* *cnK SURFACE WATER UONITORIHG S1TE
@ OISCCNTIMEO SURFAS€ WATCR UONITORiHO SITE
Figure 4.2.%1. Locations of Temporary Monitoring Wells-Wesf
DOFGnnd Junrlios Oiiire OU Ill IRA I'rog~r.%r llrpon . ..
f SCALE IN FEET
700 350 0 700 1400 2100
M:\MSC\OJ5\OOll\Ol\QOO2O4AAOWG 09/25/00 10:03om J50191
OU Ill GROUND WATER AND
SURFACE WATER MONITORING
LOCATIONS-WEST
DATE PREPAREO:
SEPTEMBER 25, 2000
FILENAME:
Q00204AA
This page intentionally left blank
Document Number 40019700 Monitoring and Additional Data Colleclion
Figure 4.2.3-2. Locations of lemporary Monitoring Wells-East
MI:IIGnnd Itnorlion Oflice 011 111 IIW I'rc>:.- cr l!s:gon
I
SCALE IN FEET I 700 0 700 1400 2100
M:\MSG\O~~\OO~~\O~\QOO~O~AA,O~; 08/14/00 08:51orn J50191
U.S. DEPARTMENT OF ENERGY n &momTrmYem
OU Ill GROUNDWATER AND
SURFACE WATER MONITORING
LOCATIONS - EAST
DAE PREPARED:
AUGUST 14, 2000
FILENMIE:
400205AA
This page intentionally left blank
Document Number Q0019700 Monitoring and Additional Data Collection
Figure 4.2.>3. Well Location Map PeRTArea
ImFllinnd lltnrlion Mrr rill III IRA 1. ....<- ~~,~~n
This page intentionally left blank
Document Number 4001 9700 . - -. .. - . hlonitori~lg and Additional Data Collection
LEGEND
PW-21
0 PeRT PERFORMANCE
MONITORING WELL
OU Ill MONITORING a WELL
Figure 4.2.3-4. Monitoring Locations in PeRT Gate Area
This page intentionally left blank
Document Number Q0019700 Monitoring and Additional Data Collection
4.2.4 Installation and Monitoring of Permanent Wells
Seven monitoring wells were installed in June 2000 for long-term use. Subcontracted drilling
services were provided by Boart Longyear. Drilling was accomplislted with a Sonic-150 drill rig.
All wells were 2-inch schedule 40 PVC. Well screens were 0.010-inch machine slotted PVC,
5 feet in length. The bottoms of the screens were set at or just below the bedrock surface. New
permanent well locations are shown in Figure 4.2.3-1.
Wells MWOO-O1 and MW00-02 will be used to monitor alluvial ground water entering the
fornier Millsite from the west. These locations will eventually replace background well 92-05 if
ground-water quality is shown to be similar. Well MW00-3 was placed at the downgradient
terminus of Deer Draw. This area recently became of interest when elevated uranium was
detected in nearby seep samples. Wells MW00-04 and MWO(M8 were installed in the axis of
the alluvial valley and will be used for monitoring ground water as it exits the former Millsite.
These wells were likely installed in backfill and presently do not produce enough water to
develop or sample. Wells MW00-06 and MW00-07 will be used to monitor the main body of
the contaminant of the contaminant plume downgradient of the PeRT wall. Quarterly monitoring
at each new well began in July 2000.
4.2.5 Evaluate Contaminant Mobility in Alluvial Aquifer
Column leach tests will be performed to evaluate leaching of contaminants from aquifGr
substrate. The column tests will use material collected below the water table and within current
or former plume areas. Samples of alluvium were collected when each new permanent well was
drilled in June 2000. Additional sam~les were collected at existine wells 88-85 and 92-07 in -
August 2000. Five tests will be run using materials collected from the plume downgradient of the
Millsite. Five tests will also be run using allu~ium from Millsite locations. These samples will be
collected from basal deposits exposed in the excavations of the former pile areas. he-aquifer
leach tests were started in August 2000.
4.2.6 Select New Locations for Long-Term Surface Water Monitoring
Four surface-water sites were added to the network in 1999 and monitored quarterly through
January 2000 (refer to Figures 4.2.3-1 and 4.2.3-2). Two were located on Montezuma Creek on
the Millsite (SW99-01 and SW99-02), one was at the pond near base of Steeie's Draw
(SW99-03), and the fourth was on the creek below the recently constructed sediment retention
pond (SW99-04). Rationale for monitoring at those locations and the results through July 1999
are included in the August 1999 status report (DOE 19990 and November 1999 data summary
report (DOE 1999e).
In April 2000, four new surface-water locations were selected for long term monitoring
(SW00-01 to SW00-04, Figures 4.2.3-1 and 4.2.3-2). SWOO-O1 is located on Montezuma Creek
at the west boundary of the former Millsite. This location will eventually replace SW92-03 as
the background monitoring location on the creek if water quality is shown to be similar. At
present, SW92-03 is monitored annually in October. Quarterly monitoring at SWOO-O1 (and
SWO(M2, SW00-03, and SW00-04) began in April 2000. Site SW00-02 will be used to
monitor water quality as the creek exits the former Millsite. SW00-03 will replace SW92-06,
DOUGrand Junction Oflice OU 111 IRA Progress Reporl
Septeniber 2000 4.69
Monitoring and Additional Data Collection Document Number Q0019700
which became inaccessible during and after surface remediation; additionally, site SW92-06 was
within a shallow, muddy, slow moving reach, resulting in a poor working environment and poor
conditions to measure stream flow. Site SW00-04 replaces SW99-04 below the downstream end
of the sediment retention pond. Extensive soil remediation occurred in the canyon upstream of
the pond. The pond was constructed to retain sediments entrained in the creek during
remediation. Results of water quality monitoring are discussed in Section 4.1 and presented in
Appendix D.
4.2.7 South Millsite Source Investigation
During a site visit on April 4-5,2000, DOE, EPA, and UDEQ decided to add two surface
waterkeep sample locations to the quarterly sampling round that was scheduled for mid-April.
The surface water that is of concern is located in the southeastern part of the Millsite,
downstrearnldowngradient of the Deer Draw drainage, in the vicinity of verification grid blocks
4307 and 521 5 (Figure 4.2.7-1). The samples that were collected on April 14,2000 were given
the names seep 4307 and seep 5215; total uranium results were 824 pg/L and 1,480 pg/L,
respectively. The results also showed a ratio of U-234 to U-238 of 1 :l; a 1:l ratio is typically
seen in water samples collected from contaminated areas on and downgradient of the Millsite.
The surface water analytical results were reviewed with the regulatory agencies. The decision
was made to conduct soil sampling in the vicinity of the seeps to determine if perhaps there was
tailings source material that had been missed during remediation. The additional sampling that
was triggered by the seep results was initially referred to as the "Deer Draw" investigation
because of the proximity of Deer Draw to the seep areas. Results of the soil samples that were
collected near the seeps indicated that the area in question did meet the verification standards
established for the Millsite. Uranium concentrations in the samples were generally below
12 mgtkg.
Additional soil samples were also collected on property MP-00391-VL Phase 111 southwest of
the seeps to investigate the possibility that supplemental standard areas on that property were
contributing to the high uranium results. Samples were collected from both verified and
supplemental standard areas. Uranium concentrations from areas not remediated were
consistently higher at the surface than those from areas that were remediated. The concentrations
of uranium in the soil samples are within the range of concentrations tested in the vadose zone
column tests summarized in Section 4.2.2 and the column effluent concentrations are within the
range seen at the seeps. This indicates that if the soil on property MP-00391-VL has the same
leaching characteristics as vadose zone material collected from the Millsite, leaching of the soils
on property MP-00391-VL may produce an effluent with a similar uranium concentrations as
seen in the seeps.
OU Ill IRA Progress Rep011 WWGrand Junclion Office
4-70 Seplember ZOO0
Monitoring and Additional Data Collection Document Numbv Q0019700
Fiuure 4.2.7-1. Temporaty Wells Near Seeps 4307 and 5215
OU 111 IRA Progress Report DOVGmnd JunctionOrIice a* 4-7 1
September ZOO0
This page intentionally left blank
Document Number QOOI9700 Monitoring and Additional Data Collection
Historical analytical data from wells completed in uncontaminated areas south of the Millsite
was reviewed. The ground water samples were collected in wells completed in the alluvium and
Mancos and Dakota Sandstone Formations. Uranium data indicated that there was a 2: 1 to 3: 1
enrichment of U-234 over U-238 (U-234 enrichment is typically seen in background wells) and
concentrations ranged from 3.73 pCin to 25.5 pCZ. A surface water sample was collected from
Deer Draw in July 2000; the uranium results for this sample was 17.9 pgL. These results are
much lower than what has been detected at the seeps indicating that the surface water that
intermittently flows down Deer Draw is not the source of the contamination at the seeps.
Similarly, background ground water in the Mancos and Dakota Formations contains detectable
concentrations of uranium, but at levels one to two orders of magnitude less than at the seeps.
Seven temporary wells along the Millsite southeastern boundary and threetemporary wells in
Deer Draw were installed during August 2000 to investigate the extent of alluvial ground water
and contamination in this area (Figure 4.2.7-1). All wells were dry except for wells T00-17,
T00-18, and T00-19. Uranium results from these wells ranged from 638 pgk to 1,110 pgk. The
dry condition found in the wells T00-24, T00-25, and T00-26 located in Deer Draw indicates
that the draw does not funnel significant ground water into the Millsite alluvium.
The investigation as to the source of water and uranium that feeds seeps 4307 and 5215 is
ongoing. Currently, the former ore storage areas south of the Millsite are being considered as
possible source areas. DOE, EPA, and UDEQ will likely identify additional field activities near
the former ore storage areas during a site visit on September 26,2000.
DOUGrand Junction Office OU Ill IRA Progress Report
September 2000 4-73
Monitoring and Additional Data Collection Document Number Q0019700
End of current text
OU 111 IRA Progress Report WVGrand Junction Office 4-74 Septen~ber 2000
Document Number Q0019700 PeRT Wall Treatability Study
5.0 PeRT Wall Treatability Study
PeRT wall treatability study activities accomplished during the year were ground water
monitoring to provide data on the treatment performance of the wall and a tracer study on the
reactive gate.
5.1. Performance Monitoring
The performance of the PeRT wall as a treatment technology is being evaluated by measuring
water levels and collecting ground water samples at 61 wells, including seven upgradient of the
wall, 40 within the reactive media, and 14 downgradient of the wall. Six locations have a shallow
and deep well pair in a transect through the center of the reactive media parallel to ground-water
flow. One well pair is located upgradient of the PeRT wall, four within the wall, and one
downgradient of the PeRT wall. The time frame of water sampling of the 61 wells covered by
this report occurred in September, October, and November 1999 and January and April 2000.
Sampling is now conducted quarterly, concurrent with annual monitoring. The location of the
wells sampled to evaluate the PeRT wall as a treatment technology are shown in Figure 5.1-1.
During each sampling event, samples were collected from all monitoring wells that yielded
sufficient water for metals analysis. Samples were also collected during each sampling event
from some of these monitoring wells for anion, cation, iron, and manganese analyses. Sample
results are presented in Appendix C.
Analytical results for the COCs (arsenic, manganese, molybdenum, selenium, uranium, and
vanadium) at each of the wells along the four major well transects through the reactive media are
summarized in Table 5.1-1. Information in the table is presented by row and by the upgradient
well number corresponding to the transect. Row 1 wells are located upgradient of the reactive
media. Row 2 and 3 wells are located in the pretreatment zone that is composed of zero valent
iron (ZVI) mixed with gravel. Row 4 and 5 wells are located in 100 percent ZVI, and Row 6 is
located downgradient of the reactive media (refer to Figure 5.1-1).
Arsenic concentrations are generally reduced to non detect levels within the pretreatment and
ZVI zones (Table 5.1-1). In samples collected downgradient of the reactive media, arsenic
concentrations ranged from non detect to 8.5 pgfl except at well R6-M4 which had
concentrations as high as 26.2 pgL. Well R6-M4 is a very slow producing well and the high
concentrations of arsenic are thought to be due to residual source in this area that has not yet
been sufficiently flushed. The most recent sample form this well (April 2000) had a
concentration of 0.73 pgL.
Manganese concentrations increase as ground water moves through the pretreatment and ZVI
zones (Table 5.1-1). An increase in manganese concentration was anticipated because
manganese is a component of the reactivemedia. There has been no increase in manganese at
permanent wells 82-07 and 82-08 located approximately 700 ft downgradient of the reactive
media.
WUGrand Junction Ofice OU Ill IRA Progress Report
Septeniber 2000 5-1
PeRT Wall Treatability Study Document Number Q0019700 I
Molybdenum, selenium, and uranium concentrations are generally reduced in the pretreatment
zone as compared to upgradient concentrations and are further reduced in the ZVI zone
(Table 5.1-1). Downgradient of the reactive media, molybdenum concentrations rebound to
levels less than or equal to upgradient concentrations. Concentrations of selenium and uranium
downgradient of the reactive media remain at relatively low levels as compared to upgradient
concentrations.
Vanadium concentrations are generally reduced to non detect levels within the pretreatment and
ZVI zones (Table 5.1-1). In samples collected downgradient of the reactive media, vanadium
concentrations ranged from non detect to 95.5 pg/L.
Table 5.1-1. Ground Water Transect on cent rations Through Gate Transects
OU 111 IRA Progress Report DOElGrand Junction Ofice
5 -2 September 2OW
Docunictit Number Q0019700 PeRT \\'all Treatabilily S~t~dy
I
GENERAL GROUND WATER FLOW DIRECTION
50' 60' 70'
RI-M3 RI-M4
ROW 4 4'
ROW 5 5 75'
ORTION OF PeRT WALL FILLED
WlTH ZERO VALENT IRON (ZVI)
25' LEGEND
f. @ R7-MI (SEE NOTE I)
SINGLE COMPLETION WELLS WlTH 5' WELL SCREENS
@ DUEL-LEVEL WELL PAIR WlTH 5' SCREENS ~ ~ ~ ~ -
PORTION OF PERT WALL HAVING 1/2" GRAVEL
WITH 13% ZERO VALENT IRON
PORTION OF PeRT WALL HAVING 1/2" GRAVEL
NOTE:
1. WELLS R8-MI, R9-MI, RlO-MI, AND R11-MI ARE LOCATED ON
20 FOOT CENTERS ALONG A WEST-NORTHWEST LINE STARTING
AT WELL R7-MI.
U.S. OE,Pk!lUFA& g:,iNERCY - CWAO &*C"Ch. CaU1.80 -
OEIAIL OF WE PERFORMANCE MONITORING ~- .~
WELL NETWORK FOR THE TREATMENT I PORTION OF THE PeRT WALL I
Figure 5.1-1. PeRT Wall Locations With Water Quality Results During This Reporling Period
IX)lYGnnd Junction Ollice OU 111 IRA Progress Ilepori
I ~:\~S~\O~~\OO~~\O~\W~IBAA.DW 08/28/00 i:26pm 550181
- OAE PREPAREO:
AUGUST 29, 2000
FILENAME:
Q00218AA
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Document Number Q0019700 PeRT Wall Treatability Study
Table 5.1-1. Ground Water Transect Concentrations Through Gate Transects (continued)
These data indicate that the reactive media is effective in reducing the concentrations of the
COCs in ground water and that downgradient of the wall, several pore volumes of clean water
will need to pass through the aquifer matrix to achieve non detectable levels. Upgradient of the
reactive media, alkalinity of the ground water ranges from 220 to 440 mgL. Within the ZVI
zone, the alkalinity drops to less than 100 mgL. A drop in the alkalinity can be used as an
indication that ground water that has passed through the reactive media as arrived at and changed
the water quality at a location. Using this infdrmation, ground water at well T99-01 located
about 700 ft downgradient of the PeRT wall shows the chemical signature of water that has
passed through the reactive media.
A PeRT Wall Treatability Study Report will be prepared during the spring of 2002 to evaluate
the first two years of ground-water monitoring and water level data. This document will be
submitted as a primary document with a draft final stipulated penalty milestone date of
September 30,2002. The PeRT wall will also be evaluated as a remedial alternative in the post-
Millsite remediation FS.
DOWGrand Junction Ofice OU 111 IRA Progrcsr Report
September 2000 53
PeRT Wall Treatability Study Document Number Q0019700
5.2. Flow Evaluation
Two of the objectives of the PeRT wall treatability study are to determine the ground-water
residence time and flow patterns within the PeRT wall and to determine the tendency for the
PeRT wall to clog. Changes in subsurface flow conditions and the degree of clogging will
ultimately impact the longevity of the PeRT wall system. A colloidal borescope in conjunction
with tracer testing was used to evaluate flow within the reactive media and to provide a baseline
data against which future observations can be compared.
The colloidal borescope is an instrument usedto measure the movement of natural colloids in a
borehole to determine the rate and direction of ground-water flow. The measurements are
considered representative only when steady direction flow is observed. Flow velocity up to
3 cm/s can be measured. Measurements were made during the week of July 26,2000, prior to the
tracer test, at wells upgradient of, downgradient of, and within the reactive media. Flow direction
and velocities are currently being evaluated to determine the capture zone, residence time,
whether there are preferential flow paths, and whether flow is directly through the reactive
media.
The reactive media tracer test began on July 17,2000 and was terminated on July 26,2000. The
colloidal borescope was during the tracer test to aid in the interpretation of the tracer test results.
Tracers used during the test were the inert gases argon and helium and anions bromide and
chloride. Preliminary analysis of the data indicates that the gases were not detected downgradient
of the injection wells and the anion tracers moved quickly and relatively directly through the
wall. Results of the borescope and tracer test are currently being evaluated and will be submitted
in a report to the regulatory agencies for review during the first quarter of fiscal year 2001. The
report will contain a description of the testing procedures, the data, and a discussion of the
results.
Figure 5.2-1 illustrates the water table surface and saturated thickness in the general area of the
PeRT wall based on April 10,2000, water level data. The surface was created using SURFER.
Water level data was interpolated by triangulation; grid cells were l-ft square. Creek elevations
were included in the analysis from which the contours in Figure 5.2-1 were created because the
creek and aquifer are assumed to be hydraulically connected. Creek elevations were higher than
adjacent ground-water levels, implying a losing stream condition, and therefore, water level
contours across the point in the downstream direction. Surface plots generated without creek
stage data also exhibited similarly shaped contours near the creek.
A ground-water divide is apparent south of the creek and west of the PeRT wall. Flow is directed
east to the permeable gate and to the south and southeast, where bypass around the southern end
of the wall is implied. Most wells below the south slurry wall have remained dry after the wall
was installed. Volumetric flow through the gate will be estimated using recently obtained tracer
tests and slug tests, in addition to hydraulic data that will be collected during fall 2000. The
amount of wall bypass can then be estimated with an analytical or numerical model, or by water
balance.
OU I11 IRA Progress Report DOEIGrand Junction Oftice
5-6 September 2000
Document Number Q0019700 PeRT Wall Treatability Study
The water table at the reactive gate is shown in Figure 5.2-2, which is identical to the previous
figure except that contour intervals and map scale differ. a steep gradient is observed along the
upgradient edge of the gate, with about 2 feet of head loss over a distance of several feet. The
gradient is very shallow across the reactive media and is again relatively steep as water exits the
gate. Ground water then spreads laterally to re-occupy the region below the gate and wall, and
the resulting level of saturation is thin. Geochemical data (e.g., alkalinity) and tracer test data
demonstrate unequivocally that ground water is flowing through the gate.
WWGrand Junction Ofice OU 111 IRA Progress Report
September 2000 5-7
PeRT Wall Treatability Study Document Number Q0019700
End of current text
OU I11 IRA Progress Report WFJGrand Junction Office
5-8 September 2000
Document Number Q001970r) PcRT Wnll TreatshiliIy Shldy - --....--.---.-.-.. -- - -
Groundwater Table &
Saturated Thickness
April 10,2000
I
0 -0 80
FEET
Figure 5.2-1. PeRT Wall Table Surface and Saturated Thickness
DOYGrand Junction Oflice OU 111 LRA Pmgress Report
Septcmkr 2000 5-9
This page intentionally left blank

Documel~t Number Q0019700 PeRT Wall Treatability Study . -- ,-- --- - - .--. - --- ----
Groundwater Table in Gate Area
April 10,2000
DOUGrand Junction Oflice OU Ill lRAPmgress Report
September 2000 5-11
This page intentionally left blank

Document Number Q0019700 Remedial Investigation
6.0 Remedial Investigation
Since drafting the last IRA Status Report in August 1999 (DOE 19990 discussion has occurred
between DOE, EPA, and UDEQ with regards to the schedule and content of the addendum to the
RI. Previously, it had been agreed that two years worth of surface-water and ground-water
monitoring data following Millsite restoration would probably be sufficient to begin preparation
of the addendum to the RI and the FS. Based on the schedule for Millsite restoration this data
would have been collected by January 2003. However, due to the slow progress on Millsite
restoration, final creek alignment, and aquifer restoration, it was decided to include surface-water
and ground-water data through October 2003 in the addendum to the RI.
The content of the RI addendum was discuss& during technical meetings April 4-5,2000 and
July 26,2000 between DOE, EPA, and UDEQ. It had previously been agreed that the RI
addendum would include a summary of the IRA data collection activities and data, an updated
baseline ground-water flow and transport model, and a reviewlupdate to the human health and
ecological risk assessments. It was agreed during the technical meeting that MODFLOWMT3D
would be used as the primary code for the ground-water modeling effort.
At the July 26,2000 meeting, the risk assessments were discussed in detail. There is no plan to
change the human health exposure scenarios that were presented in the RI finalized in September
1998 (DOE 1998b). IRIS will be consulted prior to the update to ensure that the most current
toxicity information is used. A commitment has been made to reach consensus on the toxicity
values by July 22,2003. The baseline risk of ground water ingestion (primary exposure) will be
determined using post-Millsite remediation ground water concentrations. Future ground water
concentrations will be predicted using ground-water flow and transport modeling. For exposure
scenarios that were found to be insignificant in the 1998 RI, only a screening level evaluation
will be performed.
EPA reviewed the 1998 ecological risk assessment prior to the July 26,2000, meeting. EPA
indicated that the exposure pathways and exposure parameters do not require updating and that
while toxicity reference values have been updated, the interpretations from the hazard indices
would not change. It was agreed by DOE, EPA, and UDEQ, that the updated ecological risk
assessment to be prepared in 2004 will use post-Millsite remediation surface-water
concentrations, but that dose from other media would not be updated. EPA recommended
possible future sampling for benthic macroinvertebrates. Benthic macroinvertebrate sampling
will be discussed further at future OU 111 technical meetings and the scope of this possible
sampling effort will be determined prior to October 2002 when it is thought that such an effort
might take place.
The submittal of the draft final addendum to the RI is scheduled for April 9,2004.
DOWGrand Junction Ofice OU 111 IRA Progress Report
September 2000 Page 6-1
Remedial Investigation Document Number Q0019700
End of current text
OU 111 IRA Progress Repofi WUGrand Junction Office
6-2 Seplenlber 2000
Document Number Q0019700 Feasibility Study
7.0 Feasibility Study
A number of issues have been identified that require resolution either prior to or during
preparation of the final FS. These issues are: 1) selection of the ground-water modeling code;
2) identification of preliminary remediation goals (PRGs) for each of the contaminants of
concern; 3) identification of locations for "point-of-compliance" monitoring; 4) concurrence on
the remediation time frame; and 5) concurrence on the remedial alternatives to be evaluated.
Following is a brief summary of the progress made on resolving each of these issues to date. The
draft final FS is scheduled to be submitted to the EPA and UDEQ in August 2004.
7.1. Ground Water Modeling Status
The ground-water flow and solute transport models presented in the RI (DOE 1998b) will be
updated to reflect changes to the ground water system and contaminant distributions resulting
from surface remediation. The models will also incorporate new information obtained during the
IRA that was not available during the RI. Modeling for the RI was conducted using the codes
MODFLOW and MT3D96, which are generally recognized as industry standards. The RI ground
water models will be used only as templates for constructing new models; however, the
conceptual model of flow and contaminant transport for the site will remain essentially the same.
Model selection was discussed in a meeting on April 5,2000, between DOE, EPA and UDEQ. It
was mutually agreed that DOE would use MODFLOW and MT3D as the primary codes for
future OU I11 ground water modeling. The OU I11 models will be assembled and run in Visual
MODFLOW or Ground Water Vistas. Ground Water Vistas supports both stochastic and
deterministic simulations of flow and transport. Visual MODFLOW is currently limited to
deterministic models but is being revised to support stochastic analysis and calibration to solute
concentration. The IRA Work Plan states that the primary flow and transport models will be run
deterministically. Discussions during the April 2000 meeting led to no changes to the basic
modeling approach for OU 111 as outlined in the Monticello Mill Tailings Site, Operable Unit IIZ,
Inferi~n Remedial Action Work Plan, November (DOE 19998).
Over the past year, initial data development was begun for the ground water model. Flow in
Montezuma Creek and discharge of ground water to the excavation on the Millsite has been
measured about 6 times for water budget analysis. These measurements have consistently
indicated that the ground-water flux across the central portion of the former Millsite is about 100
gallons per minute. This provides an important calibration target for the ground-water flow
model. Ground-water flux will also be calculated from data obtained from the borescopeltracer
tests conducted in the PeRT wall gate during July 2000 (Section 5.2). This will provide a second
flux target for model calibration.
7.2. Preliminary Remediation Goals
Preliminary remediation goals were developed and presented in the draft FS (DOE 1998c) for
surface water and ground water.
DOWGrand Junction Office OU Ill IRA Progress Report
Septeniber 2000 7-1
Feasibilitv Studv Document Nuniber 00019700
7.2.1 Surface Water
Achieving acceptable risk levels and compliance with applicable or relevant and appropriate
requirements (ARARs) are the two primary goals of remedial action. As shown in the RI,
contamination associated with OU 111 surface water does not cause excess risk to human health
or the environment. Therefore, the remedial action objective for surface water is simply to
prevent concentrations of COCs from exceeding State surface-water standards in "Standards of
Quality for Waters of the State," R317-2, UAC.
The current PRGs for surface water are those that were presented in the draft FS and are
presented in Table 7.2.1-1. PRGs for copper, lead, and zinc are not listed because these metals
were subsequently eliminated as COCs (see Monticello Mill Tailing Site, Operable Unit III
Surface Water and Ground Water Data Suntmary Report December 1999e).
Table 7.2.1-1. Surface-Water Preliminary Remediation Goals
7.2.2 Ground Water
,
COC
Arsenic
Selenium
Ra-226
Gross Alphaa
As shown in the RI, under current conditions there is no unacceptable risk to human health
because ground water is not being used as a drinking water source. However, risks exceed the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP) established risk range
for carcinogens and hazard index for noncarcinogens under the future-use residential scenario
because daily consumption of ground water was assumed. No unacceptable risk to ecological
receptors was identified. The remedial action objectives for ground water are to protect human
health on the basis of risk, and achieve maximum contaminant levels specified in the Federal
Safe Drinking Water Act (SDWA), or the State standard specified in "Administrative Rules for
Ground Water Quality Protection," R3 174, UAC.
Because remedial action at OU 111 is undertaken under the Federal Comprehensive
Environmental Response, Compensation and Liability Act (CERCLA), the substantive standards
of the Utah Ground Water Quality Protection Rules are considered to be met unless otherwise
determined by the Utah Executive Secretary. Therefore, DOE does not need to submit a
Corrective Action Plan, however the corrective action (remedial action) undertaken must meet
the requirements of the Ground Water Quality Protection Rule. With regard to remedial goals, a
summary of the substantive standards of the Ground Water Quality Protection Rule applicable to
OU 111 for a Corrective Action follow:
The standard for gross alpha does not exclude Rn-222 or uranium.
For contaminants with specified levels, ground-water quality standards shall be met or, where
applicable, alternate corrective action concentration limits (ACACLs). ACACLs can be
higher or lower than the standards specified in Table 1 of the Ground Water Quality
PRG
50 pglL
5.0 pglL
5.0 pCi1L
15 pCilL
Utah Surface Water Standard
OU 111 IRA Progrcss Repact DOWGrand Junction Ofice 7-2 September 2000
Domestic
50 pglL
10 pg/L
5 pCilL
15 pCiL
Agricultural
100 pglL
50 pg/L -
15 pCiL
Aquatic Wildlife
190 pg/L
5.0 pg/L -
-
Document Number 00019700 Feasibiiih, Studv
Protection Rules. Higher ACACLs shall be protective of human health and the environment,
and shall utilize best available technology.
For contaminants for which no ground-water quality standard has been established,
Corrective Action Concentration Limits (CACLs) shall be proposed. These levels shall
consider EPA MCL goals, health advisories, risk-based contaminant levels or standards
established by other regulatory agencies and other relevant information.
The ARAR-based preliminary goals proposed in the draft FS are presented in Table 7.2.2-1. A
risk-based PRG for lead-210 was proposed in the draft FS as 2 to 8 pCin. The lower
concentration presented in the range is based on the reasonable maximum exposure @ME) risk
and the higher concentration is based on the central tendency (CT) risk.
Table 7.2.2-1. Ground Water Preliminary Remediation Goals
I I t I I
Carcinogenic Nonradionuciides I
I Arsenic 1 50 irg/L I 50 pg1L 1 50 ~glL I 50 pglL I
ARAR-Based Preliminary
Remediation Goals
Regulatory Standards
coc Federal
SDWA
aT
UDEQ stated during the February 2000 FFA that arriving at a PRG using 125 percent of the ground water protection
standard as was done in the FS is not appropriate because the aquifer is already contaminated. Therefore, values
proposed in the FS are not reprinted. in this table, the PRG's for lead-210, manganese, and vanadium are based on
risk.
Key: COC =contaminant of concern; SDWA = Safe Drinking Water Act; UMTRCA = Uranium Mill Tailings Radiation
Control Act; pglL = micrograms per iiter; Pb-210 = iead-210; Ra-226 = radium-226; U-2341-238 = uranium-234
and uranium-238; pCi1L = picowries per liter; N = nitrogen
Carcinogenic Radionuclides
At the February 2000 Federal Facilities Agreement (FFA), UDEQ informed DOE that they are
developing CACLs for vanadium and manganese that may be used as PRGs. Also at the
February 2000 FFA, DOE committed to reviewing and possibly revising the PRGs presented in
the draft FS and preparing a discussion paper proposing PRGs after the radionuclide MCLs are
finalized by EPA in November 2000.
Utah Ground Water
Standards, Table 1
WWGrand Junction Off~ce OU Ill IRA Progress Report
September 2000 7-3
UMTRCA
7
Pb-210
Ra-226
U-2341238
Gross Alphaa
Gross Beta
-
5.0 pCiL
30 pCiR
15 pCiR -
2 to 8 p~il~b
5 pCilL
30 pCiR
15 pCiR
4 mrem
-
5.0 pCiL -
15 pCiR
4 mrem
-
5.0 pCVL
-
15 pCiR
4 mrem
Feasibility Study Document Number Q0019700
UDEQ presented the EPA Region 111 risk-based screening concentrations at the July 26,2000
OU 111 technical meeting and proposed that they be used as PRGs. They are 0.73 mgL for
manganese and 0.26 mg/L for vanadium.
7.3. Point of Compliance and Area of Attainment
The point-of-compliance for surface-water monitoring to determine compliance with ARARs
was discussed during the February 2000 FFA and the April 2000 OU 111 technical meeting.
UDEQ stated during the FFA meeting that DOE will be required to meet in-stream water quality
standards at least at the eastern boundary of the Millsite. At the OU 111 technical meeting it was
proposed that other "natural" points of compliance are the outlet at Sutherland's Pond (which
corresponds to the eastern most area of significant Montezuma Creek remediation) and
downstream of the Vega Creek confluence above the rugged canyon area (beyond which
accessibility is severely restricted). UDEQ is currently considering these locations.
For ground water, the area of attainment can be defined by the NCP, which states that
". . . remediation levels should generally be attained throughout the contaminated plume,
or at and beyond the edge of the waste management area when waste is left in place."
(55 Federal Register 8713)
On this basis, the point of compliance for OU 111 ground water was defined in the draft FS as that
portion of the alluvial aquifer within the boundary of the Millsite and downgradient of the
Millsite where concentrations of COCs exceed PRGs. At the February 2000 FFA and during the
April 2000 OU 111 technical meeting, EPA reiterated this position by stating that cleanup
standards must be met in ground water, not at the pump or point of distribution. Therefore, with
regards to ground water, there are currently no unresolved issues about point-of-compliance.
7.4. Remediation Time Frame
In accordance with EPA guidance (Guidance for Remedial Actions for Contaminated Ground
Water at Superfund Sites, @PA 1988]), "remediation time frame" is defined as the period of
time required to achieve remedial action objectives in ground water at all locations within the
area of attainment. DOE discussed the 40 CFR 192 (UMTRA) ground-water provisions for a
100-year remediation time frame in the draft FS; during review of the draft FS, EPA and UDEQ
both suggested that a 100-year time-frame was unacceptable.
At the February 2000 FFA, DOE questioned why the 100-year natural attenuation time frame in
40 CFR 192 is not relevant and appropriate given that 40 CFR 192 has been identified as a
relevant and appropriate regulation. EPA indicated that when a regulation is relevant and
appropriate not all parts of the regulation need to be relevant and appropriate.
Currently, there are no action items related to further discussions on remediation time frame. It is
anticipated that this topic will have been revisited with the regulatory agencies by no later than
preparation of the post-remediation FS.
OU 111 IRA Progress Report WFJGrand Junction O%ce
7-4 September 2000
Document Number 000197W Feasibility Study
7.5. Remedial Alternatives
Remedial alternatives to be considered in the post-Millsite remediation FS were discussed during
the April 2000 OU 111 technical meeting. It was agreed that due to the extensive excavation of
subpile soils during Millsite remediation, the remedial alternatives that may be considered in the
final FS are limited. Remedial alternatives currently identified are the no action alternative,
monitored natural attenuation, enhanced monitored natural attenuation, hot-spot pump and
treatment modifications to the current PeRT wall or installation of another PeRT wall, and a
combination of pump and treat with enhanced attenuation. A preliminary screening of a passive
alternative using wetlands as reducing environment to precipitate out contaminants may be
considered. These alternatives are briefly described below.
Summary of Feasibility Study Alternatives
1. No Action Alternative--The no action alternative only includes monitoring contaminant
concentration levels. It does not include any activity to reduce contaminant concentrations or
to reduce human or ecological exposure to contaminated media and assumes that no
reduction in contaminant concentrations will be achieved.
2. Monitored Natural Attenuation-The monitored natural attenuation alternative assumes
processes in the ground water and subsurface will reduce the concentrations of contaminants
over time. Monitoring the contaminant concentrations and periodic reevaluation of the length
of time until concentrations reach acceptable levels is the major activity involved in this
alternative. The alternative also includes institutional controls, such as deed restrictions, to
control human exposure to contaminated ground water.
3. Enhanced Attenuation with ~onitoring- his alternative involves pumping Burro
Canyon ground water and then infiltrating that ground water into the alluvial aquifer. This
will increase the hydraulic gradient of the alluvial ground water, causing the ground water to
flow faster and thereby, speeding or "enhancing" the natural attenuation process. As with the
monitored natural attenuation alternative, monitoring, reevaluation, and institutional controls
are part of this alternative.
4. Hot Spot Extraction and Treatment-The hot spot extraction and treatment alternative
involves extracting ground water from the most contaminated areas of the plume and then
treating the extracted ground water. Ground water would be extracted using wells located in
areas with high concentrations of contaminants. Two to four "hot spot" areas would be
addressed, however, this number may change with additional information. The alternative
does not address contaminated ground water outside the "hot spot" areas. Several treatment
options are available for the extracted ground water. Two options considered are to treat the
ground water in Pond 4 using evaporation or to use an active treatment process similar to
what was used during remediation of the Millsite. The alternative also makes use of
monitoring and institutional controls.
5. Hot Spot Extraction and Treatment with Enhanced Attenuation-This alternative
involves all the components of Alternative 4, Hot Spot Extraction and Treatment, plus uses
the components of Alternative 3, Enhanced Attenuation with Monitoring. A major aspect of
this alternative is that Burro Canyon ground water would be infiltrated into the alluvial
DOEJGrand Junction OIfice OU Ill IRA Progress Report
Scplcrnber 2000 7-5
Feasibility Study Document Number 00019700
aquifer in areas not addressed by the "hot spot" extraction. This enhances natural attenuation
in areas that are not being remediated by ground-water extraction. This alternative has a
shorter remediation time than Alternatives 3 or 4 but has higher costs than either of those
alternatives.
6. Permeable Reactive Treatment (PeRT) Wall-The PeRT wall alternative makes use of the
existing PeRT wall at the site. The existing PeRT wall was installed as a technology
demonstration project but has worked well at reducing contaminant concentrations in the
ground water. The alternative includes modification of the existing PeRT wall to enhance its
performance and may include an additional PeRT wall to treat contaminants in areas that are
not being addressed by the existing PeRT wall. Monitoring and institutional controls are also
included in this alternative.
Passive Treatment with a Wetlands Reducing Zone--This alternative makes use of an
innovative treatment process that has theoretical feasibility but which has not been demonstrated.
The alternative involves creating a wetlands area that intercepts the ground water. The plants in
the wetlands area create a reducing environment in the water that causes dissolved metals to
precipitate out of solution. As with all the other alternatives, this alternative also makes use of
monitoring and institutional controls.
OU Ill IRA Progress Repor( WWGrand Junction Offtce
7-6 Seplember 2000
Document Number Q0019700 ARARs
8.0 Applicable or Relevant and Appropriate Requirements
This section presents an updated evaluation of ARARs for the surface water and ground water in
OU 111. The CERCLA response action for OU 111 must comply with chemical-, location-, and
action-specific ARARs and attain a degree of cleanup that ensures protection of human health
and the environment. ARARs compliance must be met during the response as well as at its
completion. Remedial actions that leave any hazardous substance, pollutant, or contaminant on
site must meet a level or standard of control that at least attains standards, requirements,
limitations, or criteria that are identified as applicable or relevant and appropriate for the site.
Only substantive requirements must be met for on-site CERCLA activities; both substantive and
administrative requirements must be met for off-site activities.
Chemical-specific ARARs set health- or risk-based concentration limits for particular hazardous
substances or contaminants in air, soil, water, and other media. The principal COCs at OU I11 are
radioactive and nonradioactive substances associated with uranium and vanadium mill tailings.
Location-specific ARARs establish additional requirements on the basis of unique characteristics
of a site that could be affected as a result of remedial actiofi. These ARARs may be used to
restrict or preclude certain activities or remedial actions on the basis of location or characteristics
of a site. Action-specific ARARs are performance, design, and other requirements that control
remedial activities or actions. These requirements are not concerned with contaminants present
or with site characteristics at the location but address how a selected remedial action alternative
must he achieved. Action-specific requirements may specify particular performance levels,
actions, or technologies, as well as specific levels (or a method for setting specific levels) for
discharged or residual contaminants.
Section 3.1 addresses Federal ARARs for OU 111 surface water and ground water. Section 3.2
addresses State ARARs for OU 111 surface water and ground water.
8.1. Federal ARARs
This section addresses Federal requirements and identifies how each pertains to OU 111 surface
water and ground water. A list of applicable or relevant and appropriate Federal requirements for
OU 111 surface water and ground water is presented in Table 8.1-1.
8.1.1 Safe Drinking Water Act
The requirements of this act and its corresponding regulations address public water systems. The
requirements are implemented by the State of Utah through the federally approved program
under the Safe Drinking Water Act (SDWA). See the discussion in Section 3.2.1, "Drinking
Water" for an ARARs determination.
WWGrand Junction Ofice OU Ill IRA Progress Report
September 2000 8-1
Table 8.1-1. Federal ARARs for OU Ill Surface Water and Ground Water
Standard, Requirement, Citation
Criterion, or Limitation Description Status Comment
Safe Drinking Water Act 42 USC 300(g) Establishes health-based Relevant and appropriate Because the quality of the alluvial
National Primary and 40 CFR Part 141 standards for public water through the State of Utah aquifer could allow it to be used as
Secondary Drinking Water 40 CFR Part 143 systems (maximum contaminant, standards as a chemical- a drinking water aquifer, the MCLs
Standards levels [MCLs]): specific requirement. may apply as deanup standards.
Clean Water Act 33 USC Criteria for states to set water Applicable through the State Addresses Montezuma Creek
Water Quality Criteria 1251-1376 quality standards on the basis of of Utah standards as a contamination.
40 CFR Part 131 toxicity to aquatic organisms chemical-, location-, and
"Quality Criteria and human health. action-specific requirement.
for Water.
National Pollutant 40 CFR Parts Establishes standards for ' Applicable through the State. A point source effluent distharge
Discharge Elimination 122 through 125 discharges of pollutants into into Montezuma Creek may be
System waterways and through the use used depending on the selected
of underground injection wells. water-treatment technology.
Potential storm-water discharges
into Montezuma Creek must be
controlled. Aquifer reinjection may
be used as part of a treatment
remedy.
Dredge or Fill 40 CFR Parts Regulates the discharge of Applicable as location- and Dredged or fill material
Requirements 230 and 231 dredged or fill material into action-specific requirement requirements applicable through the
(Section 404) 33 CFR Part 323 navigable waters and manages State of Utah standards. EPA has
40 CFR Part 404 wetland areas. jurisdiction over wetlands at
CERCLA sites in the state.
Clean Air Act 42 USC Establishes sta~dards for Applicable through the State Seeks to protect and enhance the
National Primary and 7401-7462 ambient air'quality to protect of Utah standards as a quality of the netion's air resources.
Secondary Ambient Air 40 CFR Part 50 public health and welfare. chemical-, location-, and
Quality Standards action-specific requirement.
1
Standard, Requirement, Citation
Criterion, or Limitation Description Status Comment
Resource Conservation and 42 USC 6901 Regulates the generation. Applicable through the State Hazardous waste is not known to
Recovery Act (RCRA) 40 CFR Parts treatment, storage, and disposal of Utah Standards as a exist within OU Ill. However. these
260-279 . of hazardous waste. . chemical-, location-, and regulations will apply if hazardous
action-specific requirement. waste is generated during the
OU Ill treatment process.
Uranium Mill Tailings 42 USC 2022. Establishes health-based Relevant and appropriate Although the cleanup standards
Radiation Control Act 42 USC groundwater remediation chemical- and action-specific apply only to celtain specifically
(UMTRCA) 7901-7942 standards for inactive uranium requirement. designated sites where uranium
processing sites. was processed, the groundwater
deanup standards are relevant and
appropriate to,the OU Ill selected
remedy because uranium and
vanadium were processed at this
site.
National Historic Preservation . 16 USC 470 Requires Federal agencies to Applicable location- and Applies to any district, site, building.
Act 40 CFR 6.301 (b) take into account the effect of action-specific requirement structure, or object listed on or
any federally assisted for the OU Ill selected eligible for the National Register of
undertaking or licensing on a remedy. Historic Places.
structure or object that is
included on or eligible for the
National Register of Historic
Places.
Archeological and Historic 16 USC 469 Establishes procedures to Applicable as a location- and Applies if OU Ill activities affect the
Preservation Act 40 CFR 6.301(c) provide for preservation of action-specific requirement. historical or archeological sites that
historical and archeological datg have been identified near OU lg.
that mbht be destroyed through ,
alteration of terrain as a result of
a Federal construction project or
a federally licensed activity or
program.
Table 8.1-1. Federal ARARs for OU Ill Surface Water and Ground Water (continued)
Standard, Requirement, Citation
Criterion, or Limitation Description Status Comment
Fish and Wildlife 16 USC 661-666 Requires consultation when a Relevant and appropriate as The Montezuma Creek channel
Coordination Ad 40 CFR 6.302(g) Federal department or agency a location- and action- may be modified during OU Ill
proposes or authorizes any specific. requirement. activities, which may result in
modification of any stream or tempora~y habitat loss for wildlife
other water body; requires species.
adequate provisions for
protection of fish and wildlife
resources.
Endangered Species Act 16 USC Requires that Federal agencies Applicable as a location- and Currently threatened or endangered
1531-1543 ensure that any action action-specific requirement. species or critical habitat have not
50 CFR Parts 17 authorized, funded, or carried been identified in OU Ill. Applies if
and 402 out by such agencies is not remedial action wilt cause
40 CFR 6.302(h) likely to jeopardize the depletions in Montezuma Creek
continued existenoe of any flow to the San Juan River greater
threatened or endangered than 100 acre-feet per year.
species or destroy or adversely
modify critical habitat.
FloodplainMletlands 40 CFR Part 6. Establishes agency policy and Applicable as a location- and Remediation actions could affect
Environmental Review Appendix M guidance for carrying out the actionspecific requirement. site floodplains and wetlands.
provisions of Executive Orders
11988, "Floodplain
Management." and 11990.
"Protection of Wetlands."
National Environmental 40 CFR 1500 Requires that all federally Relevant and appropriate as NEPA values have been and will be
Policy Ad (NEPA) , 10 CFR 1021 undertaken actions,be assessed aslocation- and action- incorporated in the CERCLA
for potential environmental specific requirement. documentation. '
impacts. All potential
environmental impacts must be
properly mitigated.
Document Number Q0019700 ARARs
Federal Water Pollution CotrtrolAct, as Amended by flre Clean Water Act
Water Quality Criteria
The water quality criteria of this act and its corresponding regulations set water quality standards
on the basis of toxicity to aquatic organisms and human health, and manage storm-water runoff
discharges. The requirements are implemented by the State of Utah through federally approved
programs under the Clean Water Act. See the corresponding discussions in Section 8.2 (Water
Quality Rules, Standards of Quality for Waters of the State, Ground Water Quality Protection,
Underground Injection Control Program, and Utah Pollutant Discharge Elimination System) for
ARARs determinations.
Dredge or Fill Requirements (Section 404)
The provisions of 40 CFR 230 and 231 and 33 CFR 323 regulate activities associated with
discharging dredged or fill material into waters of the U.S. Navigable waters and isolated
wetlands are protected under the jurisdiction of the U.S. Army Corps of Engineers; a general
permit (GP4O) was issued by the Corps of Engineers to the State authorizing the State Engineer
to regulate the discharge of dredged or fill material into Utah streams. See the discussion in
Section 8.2 for an ARARs determination.
The discharge of dredged or fill materials into waters of the U.S. (including wetland areas) is
regulated by EPA rather than the Corps of Engineers for CERCLA sites. Wetland areas have
been identified and delineated throughout OU 111. Guidelines of the Monticello Wetlands Master
Plan (DOE 1996b), which was developed to adhere to these applicable location- and action-
specific requirements, and which has been approved by EPA, will be followed for any wetland
area disturbance, remediation, and restoration activities that occur in association with the
selected OU 111 surface-water and ground-water remedy.
Clean Air Act
The requirements of this act and its corresponding regulations seek to protect and enhance the
quality of the nation's air resources in order to promote public health and welfare and the
productive capacity of the nation's population. The requirements are implemented by the State of
Utah through the federally approved program under the Clean Air Act. See the discussion in
Section 8.2.2 (Air Quality) for an ARARs determination.
Resource Conservation and Recovery Act (RCRA)
The requirements of this act and its corresponding regulations address the generation and
management of hazardous waste (RCRA Subpart C), and the management of underground
storage tanks containing regulated substances (RCRA Subpart I). The requirements are
implemented by the State of Utah though the federally approved program under RCRA, as
amended. See the discussion in Section 8.2 for an ARARs determination.
DOWGrand Junction Osee OU 111 IRA Progress Reporl
September ZOO0 8-5
ARARs Document Number Q0019700
Uranium Mill Tailings Radiation Control Act
The requirements of this act and its corresponding regulations, promulgated at 40 CFR Part 192,
are not applicable because the site does not meet the statutory or jurisdictional prerequisites that
are applicable only to 24 specifically identified inactive uranium mills and mill tailings sites.
However, these requirements are relevant and appropriate for the selected OU 111 surface-water
and ground-water remedy because mill tailing contaminants have been dispersed into the
environment. Included in these requirements are the cleanup standards for remedial actions at
inactive uranium processing sites with ground-water contamination and the process for
determining and implementing alternate concentration limits (alternate cleanup standards).
Therefore, these Federal requirements are relevant and appropriate chemical- and action-specific
requirements for the selected OU 111 surface-water and ground-water remedy.
National Historic Presewation Act
The regulations implementing this act and its corresponding regulations at 40 CFR 6.301(b)
require Federal agencies to take into account the effect of any federally assisted undertaking or
licensing on a structure or object that is included on or eligible to the National Register of
Historic Places. Because structures or objects exist near OU 111 for which a determination of
eligibility has not been made, these Federal requirements are applicable location- and action-
specific requirements for the selected OU 111 surface-water and ground-water remedy.
Archaeological and Historical Presewation Act
This act and its corresponding regulations establish procedures to provide for the preservation of
historical and archaeological resources that may be destroyed through alteration of terrain as a
result of a Federal constktion project or a federally licensed activity or program. On the basis
of recent archaeological survey results, which identify regulated resources near OU 111, these
Federal regulations are considered applicable action- and location-specific requirements for
remedial activities associated with the selected OU 111 surface-water and ground-water remedy.
Fish and Wildlife Coordination Act
This act and its corresponding regulations require consultation with the U.S. Fish and Wildlife
Service whenever a Federal department or agency proposes or authorizes modification of any
stream or other body of water and requires adequate provisions for the protection of fish and
wildlife resources. Recent flora and fauna surveys identified no fish in Montezuma Creek within
OU 111 but showed that a short-term loss of habitat for wildlife may result if the Montezuma
Creek channel is modified. Because the Montenuna Creek channel may be temporarily
disturbed, these Federal requirements are relevant and appropriate location- and action-specific
requirements for the selected OU 111 surface-water and ground-water remedy.
Endangered Species Act
This act and its corresponding regulations require that Federal agencies ensure that any action
authorized, funded, or carried out by such agencies is not likely to jeopardize the continued
existence of any threatened or endangered species or destroy or adversely modify critical habitat
OU I11 IRA Progress Report WWGrand Junction Office
8-6 September ZOO0
Document Number Q0019700 ARARs
required for the continued existence of that species. DOE currently is conducting surveys to
determine if threatened or endangered species-are present in Montezuma Creek. To date, no
threatened or endangered species were identified at or near MMTS or within OU 111; however,
these requirements are applicable location- and action-specific Federal requirements if threatened
or endangered species are identified. DOE is also calculating potential depletions in flow to the
San Juan River (of which Montezuma Creek is a tributary) that could result from re-routing
Montezuma Creek or interrupting ground water recharges to the creek during implementation of
the OU I11 selected remedy. Flows to the San Juan River are protected under this act because
endangered fish reside in the river. DOE is committed to designing its response action to ensure
minimal (less than 100 acre-feet per year) depletion of flow to the San Juan River.
Bald and Golden Eagle Protection Act
This act and its corresponding regulations, which are administered by the U. S. Fish and Wildlife
Service, provide for the preservation of bald and golden eagles through the protection of the
individual raptor and its progeny. On the basis of survey information, neither bald nor golden
eagles reside at or near the MMTS. Therefore, these Federal requirements are not applicable nor
relevant and appropriate to the OU 111 selected remedy.
Executive Orders 11988-Floodplnin Mairagemeitt, and 11990-Protectioir of Wetkith
These presidential orders and their corresponding regulations require Federal agencies to
evaluate actions they may take to avoid, to the extent possible, adverse effects associated with
direct and indirect development of a floodplain or wetland. The 10 CFR 1022 "Compliance with
Floodplain/Wetlands Environmental Review Requirements" were issued to implement the
requirements of Executive Orders 11988 and 11990. Activities associated with the OU I11
remedy may affect site floodplains and wetlands. Therefore, these orders and their corresponding
regulations are applicable Federal location- and action-specific requirements.
Farmland Protection Policy Act
The purpose of this act and its corresponding regulations is to minimize the extent to which
Federal programs contribute to the unnecessary and irreversible conversion of prime, unique, or
important farmlands to nonagricultural uses. This requirement is administered through the
U.S. National Resource Conservation Service. Because prime, unique, or important farmlands
are not located within OU 111, these Federal requirements are not applicable or relevant and
appropriate to the selected OU 111 surface-water and ground-water remedy.
National Environmental Policy Act
The National Environmental Policy Act (NEPA) and its corresponding regulations are relevant
and appropriate location- and action-specific Federal requirements for all federally funded
projects and programs, including any activities associated with the selected OU 111 surface-water
and ground-water remedy. Additional guidance that would be considered under NEPA includes
the Council on Environmental Quality regulations, 40 CFR Part 1500; DOE NEPA regulations,
WWGrand Junction Office OU Ill IRA Progress Report
September 2000 8-7
ARARs Document Number Q0019700
10 CFR 102 1 ; DOE Order 45 1.1, Impletnentalion of NEPA; and Secretariiil Policy Statement on
the National Environmental Policy Act (issued June 1994). NEPA values have been and will be
incorporated into the CERCLA documentation.
8.2. State of Utah ARARs
Because MMTS is in Utah, compliance with all State-specific environmental rules, regulations,
standards, criteria, or limitations that are applicable or relevant and appropriate to the selected
OU I11 surface-water and ground-water remedy is mandatory. This section addresses State of
Utah requirements and identifies how each may pertain to OU 111 surface-water and ground
water. The authorization process for allowing a state to implement a Federal program is
generally a phased process. Because of this, the State of Utah may not have adopted a specific
rule or portion of a regulatory program. In such instances, if a nonadopted ruir ar regulation in a
state-implemented program is an ARAR, the Federal standards will apply. A list of applicable or
relevant and appropriate State of Utah requirements for OU 111 surface-water and ground water is
presented in Table 8.2-1.
8.2.1 Drinking Water
Drinking Water Rules-These rules represent the State's implemented version of the Federal
Safe Drinking Water Act's National Primary and Secondary Drinking Water Regulations, which
contain criteria and procedures to ensure a supply of drinking water that dependably complies
with maximum contaminant levels. They include quality control and testing procedures that
ensure proper operation and maintenance of a potable public water supply system, specify the
minimum quality of water that may be taken kt0 the system, and provide siting requirements for
new facilities for public water systems. They also establish maximum contaminant levels that
may be considered when establishing cleanup standards. EPA is in the process of revising
existing MCLs for radionuclides; new radionuclide standards will also be promulgated. The
ultimate effect will be to limit the amount of radionuclides found in drinking water. It is
anticipated that these rules will become effective in November 2003, and that the State of Utah
will become authorized to implement the new rules.
Because the alluvial aquifer is not used as a public water supply system, these requirements are
not applicable. However, because the alluvial aquifer is of a quality that would allow it to be
used as a drinking water source, the Utah Drinking Water Rules are relevant and appropriate
chemical-specific requirements for the selected OU 111 surface-water and ground-water remedy.
Wafer Quality
This is the State-implemented version of the Federal Clean Water Act program.
Water Quality Rules
The definitions for water pollution and the general requirements are applicable chemical-,
location-, and action-specific requirements fof the selected OU 111 surface-water and ground-
water remedy.
OU 111 IRA Progress Report DOWGrand Junction Oflice
8-8 September 2000
Table 8.2-1. State AR4R.s for OU 111 Surface Water and Ground Water
DepartmentlDivision Subject Statute Rule Comments
Department of Safe Drinking Water Rules Title 19. Chapter 4. R309. Utah This is the State-implemented Safe Drinking
Environmental Quality. Utah Code Administrative Water Act program. The quality of the alluvial
Division of Drinking Water Annotated (U.C.A.) Code (U.A.C.) aquifer could allow it to be used as a drinking-
water aquifer. Relevant and appropriate
chemical-specific requirement
Department of Definitions and General Title 19. Chapter 5. R317-1. U.A.C. Applicable chemical-, location-, and action-
Environmental Quality. Requirements U.C.A. specific requirement.
Division of Water Quality
Standards for Quality for Title 19. Chapter 5. R317-2. U.A.C. These ~les are specific to Utah waters. though
Waters of the State U.C.A. they are derived in part by using Federal criteria.
See particularly the nondegradation policy in
R317-2-3. Applicable chemical-. location-. and
action-specific requirement.
Groundwater Quality Protection Title 19. Chapter 5. R317-5. U.A.C. There is no corresponding Federal program.
U.C.A Applicable chemical- and action-specific
requirement.
Utah Underground Injection Title 19. Chapter 5. R317-7. UA.C. Applicable chemical- and action-specific
Control U.C.A. requirement if Class V injection wells are used in
association with a water treatment technology.
Utah Pollutant Discharge Title 19. Chapter 5. R317-8. U.A.C. Applicable chemical-, location-, and action-
Elimination System U.C.A. specific requirement a point-source effluent
discharge into Montezuma Creek is used in
association with a water treatment technology.
Applicable location- and action-specific
requirement; potential storm-water runoff into
Montezuma Creek needs to be controlled.
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ARARs Document Number 00019700
Standnr(1s of Qrtality for Waters of tlre State
The Clean Water Act provides criteria for states to set water quality standards on the basis of
toxicity to aquatic organisms and human health. These rules are specific to Utah waters and are
applicable chemical-, location-, and action-specific requirements for the selected OU I11 surface-
water and ground-water remedy.
Utah Pollutant Discltarge Elimination System
The UPDES rules address point-source discharges of pollutants and storm-water runoff
discharges into Utah waterways. They also address the use of injection wells (i.e., underground
discharges of water) through the Underground Injection Control Program. These rules are
applicable chemical-, location-, and action-specific State of Utah requirements if a point-source
discharge into Montezuma Creek is used in association with a water treatment technology. These
rules are also applicable location- and action-specific State of Utah requirements for controlling
storm-water runoff associated with construction activities. Additionally, the rules associated with
the Underground Injection Control program are applicable chemical- and action-specific State of
Utah requirements for the use of Class V injection wells if aquifer reinjection is included in the
selected OU I11 surface-water and ground-water remedy.
Grorrttd Water Qnality Protection
Utah-specific ground-water protection standards are addressed by this rule. An equivalent
Federal program does not exist. These ground water rules are applicable chemical-, location-,
and action-specific State of Utah requirements for the selected OU I11 surface-water and ground-
water remedy.
Dredge or Fill Requirements (Section 404)
These rules, which are implemented by the State Engineer, are applicable location- and action-
specific requirements for any dredge or fill activities in Montezuma Creek, including stream
channel alterations, associated with the selected OU I11 surface-water and ground-water remedy.
8.2.2 Air Quality
The Utah Air Conservation Rules address the prevention and control of air pollution sources in
Utah and establish air quality emission standards and monitoring requirements. Because air
emissions may occur as part of OU I11 water treatment technologies, and fugitive dust could be
generated through the clearing of land, use of construction equipment, and construction and use
of haul roads, the state-implemented version of the Federal National Primary and Secondary
Ambient Air Quality Standards program, which establish standards for ambient air quality, and
the National Emission Standards for Hazardous Air Pollutants program, which establishes
standards for new stationary sources, are applicable chemical-, location-, and action-specific
State of Utah requirements for the selected OU I11 surface-water and ground-water remedy.
OU Ill IRA Progress Repon IX)WGrand luncfion Office
8-12 Seplember 2000
Document Number Q0019700 ARARs I
Utah Hazardous Waste and Underground Storage Tank Management
Subpart C of RCRA addresses the generation, treatment, storage, disposal, and transportation of
hazardous waste. Part 261.4 (a)(4) of 40 CFR excludes mill tailings (source, special nuclear, or
by-product material, as defined by the Atomic Energy Act of 1954) from meeting the definition
of a hazardous waste. Subpart I of RCRA regulates underground storage tanks (USTs) that are
used to store regulated substances. On the basis of historical land-use knowledge and field
investigations, it is unlikely that hazardous waste or USTs are present within OU 111. However,
hazardous waste may be generated during the implementation of the selected OU 111 surface-
water and ground-water remedy (e.g., waste-treatment process wastes). Therefore, the hazardous
waste rules are applicable chemical-, location:, and action-specific State of Utah requirements if
hazardous waste is discovered or generated. To the extent possible, hazardous waste will be
managed in accordance with the Monticello Remedial Action Project, Special Waste
Management Plan for the Monticello Mill Tailings Site and Vicinity Properties (DOE 1997e).
The State of Utah UST requirements are not applicable or relevant and appropriate to the
selected OU 111 surface-water and ground-water remedy.
Corrective Action Cleanup Standards Policy for CERCLA and U~tderground Storage Tank
Sites
This policy is a Utah-specific requirement that establishes a cleanup standards policy for
CERCLA and UST sites. The policy sets forth criteria for establishing cleanup standards and
requires source control or removal, and prevention of further degradation. This policy is an
applicable chemical-, location-, and action-specific State of Utah requirement for the selected
OU 111 surface-water and ground-water remedy.
Radiation Control
These State rules address the management, including disposal and transportation, of radioactive
materials. They also address licensing requirements and standards for protection against
radiation. These rules are applicable chemical- and action-specific State of Utah requirements for
the selected OU III surface-water and ground-water remedy.
Utalr State History
These requirements address the protection of archaeological, anthropological, and
paleontological resources on State lands and lands associated with proiects conducted or
approved by State agencies. These location- and action-specific state of ~tah requirements are
applicable to activities associated with the selected OU 111 surface-water and ground-water
remedy.
Water Rigltis
These requirements, which include well-drilling and abandonment standards, and consumptive
use of water not already permitted to OU I, are applicable action- and location-specific State of
Utah requirements for the selected OU I11 surface-water and ground-water remedy.
WUGrand Junction Oftice OU I11 IRA Progress Report
September 2000 8-13
ARARs Document Number Q0019700
8.3. To-Be-Considered
This section discusses guidance, advisories, or criteria that are not promulgated, and therefore
cannot be considered ARARs, but which may be used to establish protective CERCLA remedies
for the OU 111 surface-water and ground water.
Imple~nentafion Guidance for Radionuclides:
EPA addresses radionuclide monitoring of drinking water in the draft document Implementation
Guidance for Radionuclides (EPA 2000). This guidance discusses circumstances that could
require that monitoring of radionuclides occur at the point of entry to the distribution system
instead of at the tap. Thus, the quality criteria would apply to the raw water (within the ground
water system) instead of the water potentially treated by the public drinking water treatment
system.
OU 111 IRA Progress Report DOWGrand Junction Ofice
8-14 Seplcmber 2000
Document Number Q0019700 -- Retkrenccs - - - - -- - - -
9.0 References
U.S. Department of Energy (DOE), 1990. Mortticello Mill Tailirtgs Site: Declaratiorr for the
Record of Decisiorr arrd Record of Decision Stintntary, DOE/ID112584-50, prepared for the
U.S. Department of Energy Grand Junction Office, Grand Junction, Colorado, August.
, 1996. Morzticello Wetlands Master Plan, P-GJPC926, prepared for the
U.S. Department of Energy Grand Junction Office, March.
, 1998a. Record of Decisiorr for and Interint Rernedial Actiort at the Mortticello Mill
Tailirrgs Site, Operable Unit III-Storface Water and Grourtd Water, GJO-98-5 1-TAR, prepared
by MACTEC for the U.S. Department of ~ner~~ Grand Junction Office, Grand Junction,
Colorado, April.
, 1998b. Morrficello Mill Tailiitgs Site, Operable Unit III, Remedial Ittvestigatiorr,
GJO-97-&TAR, prepared by MACTEC for the U.S. Department of Energy Grand Junction
Office, Grand Junction, Colorado, January.
. . .
, 1998~. Morrticello Mill Tailii~gs Site, Operable Unit III, Feasibility Study of Strrface
Water and Grotrrrd Water, GJO-97-21-TAR, prepared by MACTEC for the U.S. Department of
Energy Grand Junction Office, Grand Junction, Colorado, March.
, 1999a. Mortticello Mill Tailitrgs Site, Operable Uitit III, Inte,.int Remedial
Desigrt/Rernedial Actioir (RDIRA) Work Plan for Operable Urtif III-Stirface Water arrd Grotind
Water, Draft Final, MAC-MSG 2.2.1, prepared by MACTEC for the U.S. Department of Energy
Grand Junction Office, Grand Junction, Colorado, March.
, 1999b. Morrticello Mill Tailings Site, Operable Unit Ill, Interirit Remeclial Action Work
Plan, MAC-MSG 2.2.4, prepared by MACTEC for the U.S. Department of Energy Grand
Junction Office, Grand Junction, Colorado, May.
, 1999~. Mortticello Mill Tailings Site, Operable Unit III, Irtterirtr Rer~redial Action,
Sttrface Water and Grouiid Water Monitoring Plan, MAC-MSGRAP 1.3.5-1, prepared by
MACTEC for the U.S. Department of Energy Grand Junction Office, Grand Junction, Colorado,
July.
, 1999d. Monticello Mill Tailiirgs Site, Operable Unit III, Irrterint Rentedial Action,
Stirface Water artd Grotrrrd Water Moiiitorirtg Plan, MAC-MSGRAP 1.3.5-1, prepared by
MACTEC for the U.S. Department of Energy Grand Junction Office, Grand Junction, Colorado,
December.
, 1999e. Morrticello Mill Tailirrgs Site, Operable Unit III, Sttrface Water and Grottnd
Water Data Stmrrtzary Report, GJO-99-13&TAR, prepared by MACTEC for the U.S.
Department of Energy Grand Junction Office, Grand Junction, Colorado, November.
, 1999f. Mottticello Mill Tailiitgs Site, Operable Urtit III, Interint Rerrieclial Actiotr Annual
Stattis Report, GJO-99-104-TAR, prepared by MACTEC for the U.S. Department of Energy
Grand Junction Office, Grand Junction, Colorado, August.
DOWGrand Junction Oflice
Scptcmber 20W
OU 111 IRA Progrcss Report
9-1
References Docunlent Number Q0019700
U.S. Department of Energy (DOE), 1999%. Mor~ticello Mill Tailings Site, Operable Unit III.
Ittferirn Rentedial Action, Work Plan, GJO-99-129-TAR, prepared by MACTEC for the U.S. 1
Department of Energy Grand Junction Office, Grand Junction, Colorado, November.
,2000. Erivirorirnental Sciences Laboratory. Colztnin Leaclting of Unsaticrated Zone
Sedirnertts, Monticello Mill Tailings Sire-Operable Unit 111, Monticello, Umh,
ESL-RPT-2000-11, prepared by MACTEC for the U.S. Department of Energy Grand Junction
Office, Grand Junction, Colorado, August.
U.S. Environmental Protection Agency, 1988. Guidance for Rentedial Actions for Cotrtarninated
Ground Water at Stcperfiotd Sites, OSWER Directive 92831-2C.1, prepared by the Office of
emergency and Remedial Response, December.
,2000. Irnp/ernentation Guidance for Radionuclides, EPA 816-D-00-002, prepared by
the Office of Water, May.
OU 111 IRA Progress Repor( DOWGrand Junction Office
9-2 Scptembcr 2000