EPA 520/1-88-023
March 1989
GROUND-WATER PROTECTION STANDARDS
FOR INACTIVE URANIUM TAILINGS SITES
(40 CFR 192)
BACKGROUND INFORMATION
FOR
FINAL RULE
Office of Radiation Programs
Environmental Protection Agency
Washington, D.C. 20460
-------
-------
CONTENTS
Chapter 1: Introduction 1-1
References 1-2
Chapter 2: Background 2-1
2.1 Legislative history 2-1
2.2 Rulemaking history 2-1
2.3 Information considered in developing the standards . 2-2
2.4 References 2-3
Chapter 3: Site Description and Status 3-1
References 3-30
Chapter 4: Compilation and Analysis of Ground Water Data
for 14 Sites * 4-1
4.1 Introduction 4-1
4.2 Ambrosia Lake, New Mexico 4-3
4.3 Canonsburg, Pennsylvania ' 4-18
4.4 Durango, Colorado 4-26
4.5 Grand Junction, Colorado 4-40
4.6 Gunnison, Colorado 4-50
4.7 Lakeview, Oregon 4-58
4.8 Mexican Hat, Utah 4-72
4.9 Monument Valley, Arizona 4-78
4.10 Riverton, Wyoming 4-104
4.11 Salt Lake City, Utah . 4-118
4.12 Shiprock, New Mexico 4-124
4.13 Tuba City, Arizona 4-129
4.14 Green River, Utah 4-137
4.15 Rifle, Colorado (old and new sites) 4-151
4.16 Current uses of contaminated ground water 4-162
4.17 Organic contaminants in ground water 4-179
4.18 Ground-water classification 4-191
4.19 References 4-194
Chapter 5: Ground-Water Restoration 5-1
5.1 Treatment technology 5-1
5.2 Volumes of contaminated ground water 5-12
5.3 Aquifer restoration cost ranges 5-17
5.4 References 5-19
Chapter 6: Costs of Ground-Water Restoration and Monitoring . 6-1
6.1 Amount of contaminated ground water 6-1
6.2 Amount of ground water to be removed 6-1
6.3 Treatment of contaminated ground water 6-3
6.4 Estimated cost of restoration treatment 6-3
6.5 Estimated cost of monitoring 6-4
6.5.1 Estimated monitoring costs at treatment
plants 6-4
6.5.2 Estimated monitoring costs of ground water . 6-6
6.6 Total estimated cost 6-6
111
-------
6.7 Review of DOE cost estimates 6-7
6.7.1 DOE cost estimates 6-7
6.7.2 Evaluation of DOE cost estimates 6-8
6.8 References 6-12
Chapter 7: Other Considerations . 7-1
7.1 Concentrations limits for molybdenum, uranium,
radium and nitrates 7-1
7.1.1 Molybdenum ..... 7-1
7.1.2 Uranium 7-3
7.1.3 Radium ..... 7-6
7.1.4 Nitrates 7-6
7.2 Institutional control 7-6
7.3 Post-remediation ground-water contamination .... 7-17
7.3.1 Groundwater intrusion 7-17
7.3.2 Precipitation 7-18
7.3.3 Construction water 7-18
7.3.4 Construction of final cover 7-18
7.4 References 7-23
List of Figures
Number
Page
3-1 Location - UMTRA project sites ..... 3-2
4-1 Approximate location of domestic wells sampled
at Gunnison 4-176
4-2 Locations of monitor wells for UMTRA investigation
(Gunnison) ..... 4-177
4-3 Uranium plume near pile (Gunnison) , . . 4-178
4-4 DOE monitor well locations, Monument Valley site ..... 4-180
4-5, Sulfate plume, Monument Valley site . . 4-186
4-6 Nitrate plume, Monument Valley site 4-187
4-7 Uranium plume, Monument Valley site „ . . 4-188
.5-1 Location - UMTRA project sites 5-2
5-2 Low-permeability barrier reduces induced flow
from river 5-5
5-3 Chemical precipitation and associated process steps „ . . 5-7
5-4 Schematic of ion exchange 5-9
5-5 Schematic of carbon adsorption 5-1.1
7-1 Typical UMTRA project pile layout . 7-19
7-2 "Checklist" top cover ....... 7-21
List of Tables
Number
Page
3-1 Demographics of inactive uranium mill tailings sites . . 3-3
iv
-------
List of Tables (continued)
Number
3-2
3-3
3-4
3-5
3-6
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
Summary descriptions of inactive uranium mill
tailings sites .
Meteorological data for inactive uranium mill
tailings sites
Radioactivity in inactive uranium mill tailings piles
Average concentration of elements found in inactive
uranium mill tailings
Ground water matrix .
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Ambrosia Lake, New Mexico .
Site water quality compared to other EPA standards,
Ambrosia Lake, New Mexico
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Canonsburg, Pennsylvania
Site water quality compared to other EPA standards,
Canonsburg, Pennsylvania
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Durango, Colorado
Site water quality compared to other EPA standards,
Durango, Colorado
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Grand Junction, Colorado
Site water quality compared to other EPA standards,
Grand Junction, Colorado . .
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Gunnison, Colorado . . . .
Site water quality compared to other EPA standards,
Gunnison, Colorado
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Lakeview, Oregon
Site water quality compared to other EPA standards,
Lakeview, Oregon
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Mexican Hat, Utah
Site water quality compared to other EPA standards,
Mexican Hat, Utah
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Monument Valley, Arizona
Site water quality compared to other EPA standards,
Monument Valley, Arizona .
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Riverton, Wyoming
Site water quality compared to other EPA standards,
Riverton, Wyoming . .
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Salt Lake City, Utah . . .
Site water quality compared to other EPA standards,
Salt Lake City, Utah
Site water quality compared to EPA standards
at 40 CFR 192.32(a), Shiprock, New Mexico . . .
Page
3-4
3-15
3-16
3-18
3-19
4-4
4-10
4-20
4-22
4-27
4-32
4-41
4-45
4-51
4-54
4-59
4-64
4-73
4-75
4-79
4-89
4-105
4-110
4-119
4-121
4-125
v
-------
List of Tables (continued)
Number
Page
4-22 Site water quality compared to other EPA standards,
Shiprock, New Mexico 4-127
4-23 Site water quality compared to EPA standards
at 40 CFR 192.32(3), Tuba City, Arizona 4-130
4-24 Site water quality compared to other EPA standards,
Tuba City, Arizona . ........ . . ....... 4,~133
4-25 Site water quality compared to EPA standards
at 40 CFR 192.32(a), Green River, Utah 4-139
4-26 Site water quality compared to other EPA standards,
•Green River, Utah . . . . . .... . . . . . .; . . .' 4-144
4-27 Site water quality compared to EPA standards . '
at 40 CFR 192.32(a), Rifle, Colorado (new site) . . .„ 4-154
4-28 Site water quality compared to other EPA standards,
Rifle, Colorado (new site) . . . . . . . . . . . . . . 4-156
4-29 Site water quality compared to EPA standards
at 40 CFR 192.32(a), Rifle, Colorado (old site) ... 4-158
4-30 Site water quality compared to other EPA standards,
Rifle, Colorado (old site) . . . ... . . 4-160
4-31 Ground-water quality - Gunnison - downgradient ..... 4-1.63
4-32 Ground-water qualrty - Gunnison - upgradient . . . ,'." .. 4-171
4-33 Ground-water quality - Gunnison - crossgradient . . . . ." 4-174
4-34 Exceedence of water-quality standards -.'..''
at Monument Valley . . . . ."'"%~v -;/ . . . . . .V . . . "4-181
4-35 Background water quality in alluvial aquifer,
Monument Valley site . . . . . . . . . . . . . . . '.. '. 4-182
4-36 Background wate'r quality, Shinarump and DeChellyh
sandstone aquifers 'at Monument Valley ........ 4-184
4-37 Sampling for hazardous constituents' in uranium
mill tailings liquids' . . . . •.' . . .... '.;', . . . 4-189
5-1 Volumes of contaminated ground water at selected
inactive UMT sites ...... 5-18
6-1 Aquifer restoration cost estimates 6-2
6-2 Ground-water restoration cost estimates at 17 sites
chosen by DOE for active restoration . ..... . . . 6-5
6-3 Summary table - aquifer restoration costs . . . . ... . 6-9
6-4 Comparison of DOE and EPA cost estimates for restoration
of ground water at the inactive uranium mill tailings
sites . . . ;. . . ... ... . , 6-11
7-1 Summary of uranium concentrations in ground water .
at inactive uranium mill tailing sites . . ... .' . . ' 7-5
VI
-------
Chapter 1
INTRODUCTION
In enacting the Uranium Mill Tailings Radiaton Control Act of
1978 (Public Law 95-604, 42 USC 7901), the Congress found that:
o "Uranium mill tailings located at active and inactive
mill operations may pose a potential and significant
radiation health hazard to the public, and that..."
o "Every reasonable effort should be made to provide for
the stabilization, disposal, and control in a safe and
environmentally sound manner of such tailings in order
to prevent or minimize radon diffusion into the
environment and to prevent or minimize other
environmental hazards..."
To these ends, the, Act required the Environmental Protection
Agency (EPA) to set generally applicable standards to protect
the public against both radiological and nonradiological hazards
posed by residual radioactive materials at the 22 uranium mill
tailings sites designated in the Act and at additional sites
where these materials are deposited that may be designated by
the Secretary of the Department of Energy (DOE), Residual
radioactive material means (1) tailings waste resulting from the
processing of ores for the extraction of uranium and other
valuable constituents, and (2) other wastes, including
unprocessed ores or low grade materials, as determined by the
Secretary.of Energy, at sites related to uranium ore
processing. We will use the term tailings to refer^to all of
these wastes.
Standards were promulgated on January 5, 1983, however, they
were challenged in the Tenth Circuit Court of Appeals by several
industrial and environmental groups (Case Nos. 83-1014, 83-1041,
83-1206, and 83-1300). On September 3, 1985, the court
dismissed all challenges except one: it set aside the
ground-water provisions of the regulations at 40 CFR
192.20(a)(2)-(3) and remanded them to EPA "...to treat these
toxic chemicals that pose a ground-water risk as it did in the
active mill site regulations."
In the active mill site regulations (40 CFR 192 Su^parts D and
E), the EPA set general numerical standards to which the
owners/operators of the active sites had to conform to receive a
license from the Nuclear Regulatory Commission (NRG). For the
Title I sites, EPA set qualitative standards for ground water
1-1
-------
protection that allowed the DOE and NRG to determine what
actions were needed on a site-by-site basis. It was this
standard that was rejected by the courts and has resulted in the
rulemaking for which this is the Background Information Document
(BID).
Standards were proposed on September 24, 1987 for ground water
protection at the inactive uranium mill tailings sites (EPA
87a). Public hearings were held in Durango, Colorado on October
29, 1987. The public comment period was closed on January 29,
1988 (EPA 88). A draft Background Information Document was
issued with the proposed standards (EPA 87b). Comments received
during the public comment period have been considered and
incorporated where applicable in the development of the final
standards. A separate "Response to Comments" document (EPA
520/1-88-055) contains EPA's detailed responses to the comments
received and is available upon request.
The purpose of this final BID is to summarize the information
and data considered by the Agency in developing the ground-water
protection standards. New information supplied by the
Department of. Energy has also been included. Information in the
final environmental impact statements for previous rulernakings
for uranium mill tailings (EPA82, EPA83) was also considered in
this rulemaking. Further, the National Academy of Science
report, "Scientific Basis for Risk Assessment and Management of
Uranium Mill Tailings," (NAS86) was also considered by the
Agency.
Chapter 2 of the BID presents a brief description of the Title
II ground water standard and how it can be used to develop the
Title I rulemaking. A description of the 24 designated uranium
tailings sites and their current status in the DOE remedial
action program is included in Chapter 3. Chapter 4 presents a
detailed analysis of the available data on the ground water in
the vicinity of 14 of the 24 sites.
Chapter 5 describes different methods that can be used Łor the
restoration of ground water. DOE may use these methods or may
use others that they consider more appropriate. The costs of
using these restoration methods are discussed in Chapter 6.
Lastly, Chapter 7 contains other considerations pertinent to the
proposed standards.
REFERENCES
EPA82 ENVIRONMENTAL PROTECTION AGENCY, Final Environmental
Impact Statement for Remedial Action Standards for
Inactive Uranium Processing Sites (40 CFR 192), EPA
520/4-82-013-1 and 2, U.S. Environmental Protection
Agency, 401 M St, SW, Washington, D.C. 20460 (October
1982)
1-2
-------
EPA83 ENVIRONMENTAL PROTECTION AGENCY, Final Environmental
Impact Statement for Standards for the Control of
Byproduct Materials from Uranium Ore Processing (40 CFR
192), EPA 520/1-83-008-1 and 2, U.S. Environmental
Protection Agency, 401 M St, SW, Washington, B.C. 20460
(September 1983)
EPA87a ENVIRONMENTAL PROTECTION AGENCY, Standards for Remedial
Actions at Inactive Uranium Processing Sites; Proposed
Rule, 52 FR 36000, Sept 24, 1987.
EPA87b ENVIRONMENTAL PROTECTION AGENCY, Ground Water Protection
Standards for Inactive Uranium Tailings Sites -
Background Information for Proposed Rule, EPA
520/1-87-014, July 1987.
EPA88 ENVIRONMENTAL PROTECTION AGENCY, Standards for Remedial
Actions at Inactive Uranium Processing Sites, 53FR 1641,
January 21, 1988. ———
NAS86 NATIONAL ACADEMY OF SCIENCE, NATIONAL RESEARCH COUNCIL,
Scientific Basis for Risk Assessment and Management of
Uranium Mill Tailings, National Academy Press,
Washington, B.C. 20418 (1986)
1-3
-------
-------
Chapter 2
BACKGROUND
2.1 LEGISLATIVE HISTORY
The early history of uranium milling was discussed in Chapter 2
of the Final Environmental Impact Statement for Remedial Action
Standards for Inactive Uranium Processing Sites (40 CFR 192),
EPA 520/4-82-013-1, October 1982.In 1978 Congress passed
Public Law 95-604, the Uranium Mill Tailings Radiation Control
Act of 1978 (UMTRCA). UMTRCA was divided into two parts; Title
I covering 22 inactive and abandoned sites and Title II covering
those sites for which licenses had been issued by the Nuclear
Regulatory Commission or its predecessor or by an Agreement
State. Under this Act, the Environmental protection Agency was
charged with developing standards of general application to
govern the remedial activities of the Secretary of Energy or his
designee under section 275a. of the Atomic Energy Act of 1954
for those sites identified under Title I. The Department of
Energy identified two additional sites to be included under the
provisions of Title I, bringing the total number of sites under
Title I to 24. The standards to be promulgated under Title I
were required, to the maximum extent practicable, to be
consistent with the requirements of the Solid Waste Disposal Act
(SWDA) as amended. The SWDA includes the provisions of the
Resource Conservation and Recovery Act (RCRA).
2.2 RULEMAKING HISTORY
On June 11, 1979, a Federal Register Notice requesting
information and data relevant to the development of the
standards and of a report to Congress on uranium mining wastes.
Because UMTRCA required EPA to promulgate standards before DOE
could begin cleanup of tailings and because some buildings had
been found to be contaminated with tailings resulting in
radiation levels which were highly dangerous to anyone exposed
to them for a long time, interim standards for cleanup of
residual radioactivity that had contaminated land and buildings
were published in the Federal Register on April 22, 1980. This
allowed DOE to proceed with the cleanup of offsite tailings
contamination without waiting for the formal promulgation of a
regulation through the EPA rulemaking process. At the same
time, proposed standards for the cleanup of the inactive mill
tailings were published for comment.
The proposed cleanup standards were followed by proposed
disposal standards that were published in the Federal Register
on January 9, 1981. The disposal standards applied to the
tailings at the 24 designated sites and were designed to place
2-1
-------
them in a condition which will be safe for a long time. Final
standards for the disposal and cleanup of inactive uranium mill
tailings were issued on January 5, 1983. The American Mining
Congress and others immediately petitioned the Tenth Circuit
Court of Appeals for a review of the standards.
On September 3, 1985, the Tenth Circuit Court of Appeals upheld
the inactive mill tailings standards except for the ground-water
protection portions located at 40 CFR 192.20(a)(2) and (3) which
were remanded to EPA for revision. EPA had promulgated
qualitative standards for ground water protection and the Court
found that quantitative standards similar to those promulgated
for the sites that were regulated under UMTRCA Title II were
necessary. The Court did not set a time limit on establishing
the new standards. On June 2, 1986, the U.S. Supreme Court
declined to review all appeals of decisions on this case. As
noted in Chapter 1, the Agency proposed ground water standards
on September 24, 1987.
2.3 INFORMATION CONSIDERED IN DEVELOPING THE STANDARDS
In 1986, Congress passed the Superfund Amendments and
Reauthorization Act which amended the Comprehensive
Environmental Response, Compensation, and Liability Act of
1980. In the discussion of this bill, Congress established the
concept that the Administrator be allowed to use alternate
technologies where applicable standards set under other
environmental laws are based on specific technologies. The RCRA
amendments to SWDA provided only minimal direction from Congress
for the cleanup of old contamination that' existed before RCRA
was promulgated. Therefore, EPA is using part of the SARA
philosophy in the the cleanup portions of the Title I standards
by incorporating some of the provisions from SARA into the Title
I ground-water standards. These provisions are an exemption if
it can be shown that the cleanup of contaminated ground water is
technically impracticable from an engineering perspective and an
exemption if it can be shown that cleanup of the contaminated
ground water would cause more environmental harm than it would
prevent if the water were not cleaned up.
The Office of Ground Water Protection in EPA has developed draft
guidelines for classifying ground water based on its use or
potential use as a source of drinking water. EPA is allowing
the use of alternate standards for Class III ground water as
defined by the ground water classification system established in
EPA's 1984 Ground Water Protection Strategy.
Procedures for classifying ground water are presented in
"Guidelines for Ground-Water Classification under the EPA
Ground-Water Protection Strategy" released in final draft in
December 1986 and due to be finalized during the fall of 1988.
Under these draft guidelines, Class I ground waters would
encompass resources of particularly high value or that are
highly vulnerable; e.g. an irreplaceable source of drinking
2-2
-------
water or ecologically vital ground water. Class II ground
waters would include all non-Class I ground water that is
currently used or is potentially adequate for drinking water or
other beneficial use. Class III would encompass ground waters
that are not a current or potential source of drinking water due
to widespread, ambient contamination caused by natural or
human-induced conditions or inadequate capacity to provide
sufficient quantities of water to meet the needs of an average
household. Human-induced conditions would specifically exclude
the contribution from the uranium mill tailings being
regulated. At sites with Class III ground water, the proposed
supplemental standards would require only such management of
contamination due to tailings as would be required to prevent
any additional adverse impacts on human health and the
environment from that contamination.
2.4 REFERENCES
EPA79 ENVIRONMENTAL PROTECTION AGENCY, Development of Standards
for Uranium Mill Tailings and Report on Uranium Mining
Wastes; Call for Information and Data, U.S. Environmental
Protection Agency, Washington, D.C. 20460, Federal
Register, V. 44, No. 113, p. 33433 (June 11, 1979)
EPASOa ENVIRONMENTAL PROTECTION AGENCY, Interim Cleanup
Standards for Inactive Uranium Processing Sites, U.S.
Environmental Protection Agency, Washington, D.C. 20460,
Federal Register, V. 45, No. 79, pp. 27366-8 (April 22,
1980)
EPASOb ENVIRONMENTAL PROTECTION AGENCY, Proposed Cleanup
Standards for Inactive Uranium Processing Sites;
Invitation for Comment, U.S. Environmental Protection
Agency, Washington, D.C. 20460, Federal Register, V. 45,
No. 79, pp. 27370-5 (April 22, 1980)
EPA81 ENVIRONMENTAL PROTECTION AGENCY, Proposed Disposal
Standards for Inactive Uranium Processing Sites;
Invitation for Comment, U.S. Environmental Protection
Agency, Washington, D.C. 20460, Federal Register, V. 46,
No. 6, pp. 2556-63 (January 9, 1981)
EPA82 ENVIRONMENTAL PROTECTION AGENCY, Final Environmental
Impact Statement for Remedial Action Standards for
Inactive Uranium Processing Sites (40 CFR 192), EPA
520/4-82-013-1, U.S. Environmental Protection Agency, 401
M St, SW, Washington, D.C. 20460 (October 1982)
EPA83 ENVIRONMENTAL PROTECTION AGENCY, Standards for Remedial
Actions at Inactive Uranium Processing Sites, U.S.
Environmental Protection Agency, Washington, D.C. 20460,
Federal Register, V. 48, No. 3, pp. 590-606 (January 5,
1983)
2-3
-------
-------
CHAPTER 3
SITE DESCRIPTIONS AND STATUS
There are 24 processing sites (Fig. 3-1) designated under
Title I of the Uranium Mill Tailings Radiation Control Act
(UMTRCA). All but one of these sites are located in the
generally semi-arid to arid western United States. Detailed
site descriptions have been presented in Engineering Assess-
ment Reports prepared on each site for the Department of
Energy by Ford, Bacon & Davis Utah Inc. These have been
supplemented by more specific site investigations, remedial
action plans, environmental analyses and detailed ground
water quality investigations as necessary.
The sites vary in location from isolated sparsely-populated
rural settings to populated urban communities. Demographic
information for each site is presented in Table 3-1.
The sites typically are in areas of alluvium underlain by
poorly to moderately consolidated sedimentary formations.
Ground water tends to be scarce and of poor quality.
Pertinent summary information regarding the topography,
geology, hydrology, and soil characteristics of each site is
presented in Table 3-2.
The majority of the sites occur in the semi-arid to arid
western United States, in areas characterized by infrequent
but often very intense rainstorms. In the northern areas,
much of the annual precipitation may occur in the winter
months as snowfall. Site-specific precipitation and wind
records for many of the sites are lacking because of the
remote locations. Meteorological information from the
nearest comparable localities are summarized for each site
in Table 3-3.
The tailings contain residual.radioactive materials, in-
cluding traces of unrecovered uranium and most of the
daughter products, as well as various heavy metals and other
elements often at levels exceeding established standards.
The quantity of tailings, contained radioactivity, and
proposed remedial action are summarized for each site in
Table 3-4. The concentrations of specific elements which
could present public health risks through ground water con-
tamination are given in Table 3-5.
All of the sites investigated show at least local contam-
ination of groundwater by surface waters and precipitation
leaching through the tailings materials. Areal extent of
contamination ranges from the immediate vicinity of the site
to as far as 1/2 mi down-gradient. Available groundwater
contamination data are summarized in Table 3-6.
3-1
-------
Unllad Btatas Dapartniant of Enargy
Uranium Mill Tilling*
Rarnadlit Action Program
UMTRA SITE LOCATIONS
oo
ro
HIGH HEALTH HAZARD
O MiOiUfi HEALTH HA1AR8
O LOW HEALTH HAZARD
NOTE: EOQEMONT SOUTH DAKOTA VICINITY
PROPERTIES ONLY
Figure 3-1. LOCATION - UMTRA PROJECT SITES
-------
Table 3-1. DEMOGRAPHICS OF INACTIVE URANIUM HILL TAILINGS SITES
SITE NAME
Honuaent Valley, A2
Tuba City, A2
Durango, CO
Grand Junction, CO
Gunnison, CO
Hay bell, CO
Naturita (SB), CO
New Rifle, CO
| Old Rifle, CO
LO ti'
Slick Rock (NO, CO
Slick Rock (UC), CO
Louean," ID
ABbrosia Lake, NH
Shiprock, NH
Belfield, ND
Bowsan , ND
Lakeview, OS
Canonsburg, PA
Falls City, TX
Green River, UT
Hex i can Hat, UT
Salt Lake City, UT
Converse Co. , HY
Rlverton, UY
COUNTY
NAHE '
Navajo
Coconino
La Plata
Hesa
Gunnison
Hoffat
Hontrose
Garfield
Garf ield
San Higuel
San Miguel
Boise
HcKinley
San Juan
Stark
Bowaan
Lake
Washington
Karnes
Grand
San Juan
Salt Lake
Converse
Freaont
POPULATION
O-lkn
20
18
1221
843
396
0
3
96
1471
5
39
85
0
155
65
3
16
39 1O
3
14
4
203
0
.63
0-3ka
44
45
726O
16634
6523
0
3
693
5251
1O
39
172
2
3O93
1428
15
2263
17024
21
1081
384
18468
9
1069
O-5kB
6O
64
12058
38011
7315
0
3
723
5659
1O
39
218
2
4948
1584
33
4184
22135
45
1498
384
91498
18
11738
NEAREST COMMUNITY LOCAL LAND USE
NAME DISTANCE
Monuaent
Valley
Tuba City
Durango
Grand
Junction
Gunnison
Craig
Naturita
Rifle
Rifle
Slick Rock
Slick Rock
Lounan
Grants
Shiprock
Belfield
Bouaan
Lakeview
Canonsburg
Falls City
Green River
Mexican Hat
Salt Lake
City
Glenrock
Ri verton
S.Sai
25ni
2o i
3ni
3ai
25»i
O.Sni
7ai
—
lOai
Ini
1.5B1
32n i
3ai
rural grazing, IR*
rural grazing, IR*
urban, industrial
urban, industrial
urban
rural grazing
rural grazing
urban, agri-
cultural
urban, agri-
cultural
rural, grazing
rural, grazing
rural, grazing
rural, grazing
urban, aixed, IR*
urban, industrial
rural, agri-
cultural
urban, industrial
urban, industrial
rural, grazing
urban, nixed
rural, grazing, IR*
urban, industrial
rural, grazing
urban, nixe'd, IR*
WATER USES IN AREA
2 alluvial uell and seeps, domestic 8. livestock
2 sources within 2 ni
none uithin 2 ni
local sources fron deeper aquifers
numerous shallow donestic wells uithin 1 ai of site
douestic water veils 4-6 ai fro» site
3 alluvial wells upgradient, river water downstream
used for irrigation, 1 deep well within 2 ai
47 wells within 2 ni, 1 used by South Rifle for donestic
water, Colorado River major source of domestic water
local needs supplied by deep bedrock aquifers
shallow wells and surface water usage
none known
local use of groundwater from floodplain
scattered domestic and stock use
doaestic and stock use
donestic, irrigation and municipal wells 100' or more
none known
4 livestock wells uithin 2 mi
no groundwater usage near site; Green River fn tapped
none known
shallow water not used, nuaerous domestic wells
feu local wells, doaestic and stock watering
local wells belou 100 ft; United use of shallower
uater
Indian Reservation
-------
Table 3-2. SUHHASY DESCRIPTIONS OF INACTIVE URAHIUH HILL TAILINGS SITES
Honument Valley, AZ
Tuba City, AZ
Location, The site is on the Navajo Indian Reservation in Cane Valley,
Topography east of Honuaent Valley, AZ. The area is arid desert with hills,
steep ridges, and nesas. Red sandstone cliffs are proninent on
the west edge of Cane Valley.
The site is on the Navajo Indian Reservation, 5.5 »1 east of Tuba
City in Coconino County, AZ, and 85 Mi north of Flagstaff. The
area includes occasional dry washes, nesas, and rolling hills.
Geology
The site is located in a strike-valley developed on shale nenbers
of the Chinle Fornation. The site is bordered on the west by an
outcropping of the Shinarunp Henber of the Chinle Fornation and
on the east by Comb Ridge, a hogback of resistant sandstones of
Triassic and Jurassic age.
The tailings rest on a sand layer from less than 1 ft to 20 ft
thick derived from the underlying Navajo Sandstone, a weakly
cemented, nediun-grained, crossbedded sandstone. The Navajo
Sandstone dips at a low angle (2 deg) away froo the town of Tuba
City towards the axis of the Tuba City syncline. This axis runs
in a northwest-southeast direction about 1 ni east of the tail-
ings site. The Navajo Sandstone is exposed south of the mil-
site along Hoenkopi Hash.
Surface Water There are no continually active streams in the area. The site
Hydrology drains naturally into Cane Valley Wash. Approximately 1,000
acres of land are in the drainage basin that passes through the
tailings area to the wash.
There are no surface waters of consequence near the Tuba City
tailings site. Surface drainage runs to the Hoenkopi Wash about
1.5 mi south of the tailings. There is evidence of minor sheet
erosion in the area. To the north of the highway, a large de-
pression known as Greasewood Lake depression drains to the west-
southwest.
Ground Water Unconfined ground water is very near the surface along the main
Hydrology axis of Cane Valley Wash because the area is underlain by imper-
meable beds of Honitor Butte and Petrified Forest members of the
Chinle formation. These members consist of siltstones and clay-
stones and are about 700 ft. thick in the nillsite area. The un-
confined water moves through the alluvium of Cane Valley Wash and
is recovered near the site from shallow wells. These shallow
wells and springs are water table sources and their recharge is
from local runoff.
The principal aquifer in the Tuba City-Hoenkopi area is a mul-
tiple aquifer xsyste» ponsisting of the Navajo Sandstone and some
sandstone beds in the underlying Kayenta Formation. This aquifer
is recharged by winter and spring precipitation in the Kaibito
Plateau highlands some distance north of Tuba City. Water in the
multiple aquifer system moves southward from the highlands; its
principal discharge area is along Hoenkopi Wash. Thus, the tail-
ings are situated in the discharge rather than the recharge area
of the aquifer system. Water in this multiple aquifer system is
unconfined.
Waste and Soil
Characteristics
The new tailings pile (85%) is coarse-grained sand and small
pebbles containing less than 2X minus 200-mesh material. The old
tailings pile (15X) is slightly finer. Bulk densities run be-
tuesn 97 and 1O3 Ib/cu ft. Soil bsnsath both pllss is sainly
f iise-tsxtisred sand containing little soisture. The Cninle ?or=a-
tion underlies this alluvium.
The tailings are finely ground particles, a high-clay content,
relatively impermeable, and can hold water. The subsoil consists
mainly of sand and small aggregate eroded from the underlying
Navajo S&ndstone.
-------
Table 3-2. SUMMARY DESCRIPTIONS OF INACTIVE URANIUM HILL TAILINGS SITES (conf d)
Durango, CO
Grand Junction, CO
Location, The site is located on the southwest side df the city of Durango,
Topography in the valley of the Animas River. The area is surrounded by
•esas and mountains typical of the western slopes of the Rocky
Mountain Range.
The site is located on the south side of the city of Grand
Junction, CO, on the north bank of the Colorado River and adja-
cent to the industrial center of the city. The site is located
in the valley of the Colorado River, surrounded by generally arid
mesas and nountains.
Geology
Ui
The site is on a shelf betueen the Aninas River on the northeast
and the sharply rising Smelter Mountain on the southuest. The
tailings generally lie directly on Mancos Shale bedrock, but some
of the piles are on alluvium and on slag from the old lead smel-
ter. The bedrock strata dips 5 to 10 deg southeastuard. The
Mancos Shale is hundreds of feet thick beneath the tailings and
acts as a barrier to the dounuard and upward migration of ground
waters.
The site is located on the modern flood plain of the Colorado
River. A relatively thin (200-ft) section of remaining Mancos
Shale underlies the unconsolidated riverbed deposits and acts as
a barrier to the downward and upward migration of ground water.
The bedrock strata dip 5 to 10 deg toward the southwest.
Surface Hater Flowing surface waters near the site consist of Lightner Creek
Hydrology and the Animas River. Neither an intermediate regional flood
(100-yr flood) nor a uore severe standard project flood would
reach the tailings nor would such floods erode the slag bank
material which provides excellent protection for the toe of the
large pile. Even so, the potential for flooding at the present
location is significant because of the nearness of the site to
the Aninas River.
Flowing surface waters near the site consist of the Colorado
River, a drainage ditch, and several man-made facilities associ-
ated with earlier operations at the site. The Colorado River at
Grand Junction has a long history of flooding. During an inter-
mediate regional flood (100-yr flood) or a more severe standard
project flood, the tailings pile would be an island surrounded by
flood waters with unconfined ground water rising as much as 10 ft
into the pile.
Ground Water The unconfined aquifers in the Durango area consist of waters
Hydrology within the recent valley alluvium and glacial deposits. However,
it is possible that ground waters flowing through the unconsoli-
dated material could be contaminated by any such seepage. The
Mancos Shale acts as a virtually impermeable layer confining the
waters of the Dakota Sandstone. There is no possibility for con-
tamination of this potential aquifer.
The unconfined aquifers in the Grand Junction area consist of
waters within alluvial deposits, terrace deposits, weathered
rocks and soils, and in the Mancos Shale. The water table asso-
ciated with the Colorado River fluctuates several feet during the
year and may saturate some of the lowermost tailings. Any conta-
mination due to water table fluctuations would be carried by un-
confined ground waters into the Colorado River. The Mancos Shale
acts as a virtually impermeable layer that confines the waters of
the Dakota Sandstone and other stratigraphically lower aquifers.
Haste and Soil
Character!sties
Materials consist of uranium and vanadium tailings, lead smelter
slag, rubble, and contaminated earth. The tailings consist of
grey, finely ground sands with a low clay content, and bulk den-
sities of the material range between 95 and 102 Ib/cu ft.
Materials include uranium and vanadium tailings, rubble, and con-
taminated earth. The tailings consist of gray, finely-ground
sands and purple slimes. Bulk densities of the materials range
between 70.1 and 109.9 Ib/cu ft.
-------
Table 3-2. DZSC3IPTIOHS OF INACTIVE UBAHIUH HILL TAILIHGS SITES (confd)
Cunnison, CO
Haybell, CO
Location,
Topography
The site is located on the southwest aide of Gunnison, in the
valley of Gunnison Eiver and Tonichi Creek. The area is sur-
rounded by aountains uhich rise to 12,000 ft above sea level.
The site is located approxiaately 25 ai uest of the toun of
Craig, 5 «i north of the Yampa Elver in a rolling, sagebrush-
covered area.
CO
Geology
The site is located on flood plain gravels of the Gunnison Biver
and Toaichi Creek. The unconsolidated river-run aaterial under-
lying the site is at least 100 ft thick and probably 200 ft
thick. Bedrock geology consists of Hesozoic sedinentary rocks
that overlie Precaabrian igneous and aetanorphic baseaent.
The site is located on a gentle southwestern slope near the head
of a saall drainage systen. The Brouns Park Foruation underlies
the site and in turn is underlain by the Hancos Shale Foraation.
The Browns Park Foraation priaarily is coaposed of sandstone
units, and soae shale layers within the fornation act as barriers
to the downward and upward aigration of ground waters.
Surface Hater
Hydrology
The tailings pile is located 1.5 mi froa the confluence of the
Gunnison Elver and Tonichi Creek. Flooding of the tailings as a
result of peak discharges of these rivers is unlikely because the
land surface at the tailings is 10 ft above the streaa beds and
the flood plains are extensive. Under unusual conditions, such
as ice jaas in the Gunnison Eiver at the bridge of U.S. Highway
50, soae of the tailings could becoae saturated by flood waters.
The natural surface drainage froa the site is to the southwest to
the Gunnison Elver or to Toaichi Creek.
The Yaapa Eiver, 5 ai south, is the closest perennial streaa
flowing through the area doundralnage froa the site. Drainage at
the site includes diversion ditches around the pile and drainage
channels into Johnson Wash, a dry tributary of Lay Creek. Lay
Creek enters the Yaapa Eiver approxinately 2.5 ai downstreaa of
Johnson Wash. Other surface water near the site consists of
standing water in the inactive Bob Pit.
Ground Water
Hydrology
The unconfined ground water in the unconsolidated riverbed aate-
rial of the valley floor is the aajor aquifer-for city and pri-
vate water supplies. The general direction of ground water flow
parallels surface water flow to the southwest. The city's water
supplies are upgradlent froa the pile. There are. water wells
southwest of the pile and a potential for additional ground water
developaent. There has been no evidence of contaaination of
ground or surface waters, but there is a potential for such con-
taainatlon.
The unconfined ground waters of the area are within the Browns
Park Foraation and in unconsolidated valley deposits. The water
table at the site is 150 ft below the tailings-soil interface,
and the flow gradient is to the west-southwest. The confined
ground waters are either contained in the lower sections of the
Browns Park Foraation by shale layers, or are very deep aquifers
confined by the thick sequence of Hancos Shale.
Uaste and Soil
Characteristics
The aaterlal consists of uranlua tailings, dike material, and
stabilization cover. The tailings are gray-to-white finely
ground sands with a aediua clay content! bulk densities of the
saterial range bstaeen 114.6 and 127.5 Ib/cu ft.
Finely-ground sands with soae slioe and slight clay contents.
Bulk densities run between 84 and 97 Ib/cu ft. The soil beneath
the tailings consists of clayey and silty fine sands, of aedlua
density.
-------
Table 3-2. SUMMARY DESCRIPTIONS OF INACTIVE URANIUM HILL TAILINGS SITES (confd)
Naturita, CO
Rifle, CO (Old Rifle, Neu Rifle)
Location,
Topography
The site is located 2 mi northwest of the town of Haturita, in
the San Miguel River Valley. The locale is arid Uith canyons,
mesas, steep cliffs, and valleys.
The original tailings site was just east of Rifle; later dis-
posal was on land about 2 mi west of Rifle. Both sites are on
the north bank of the Colorado River.
Geology
-J
The site is located on the uest bank of the modern flood plain of
the San Miguel River, which flows northwestward through the nar-
row San Miguel River Valley. Approximately 50 ft of alluvium
overlie the shales, sandstones, and conglomerates of the Brushy
Basin Member of the Morrison Formation. Bedrock strata dip 2 to
4 deg northeastward. The Brushy Basin Member is 100 to 200 ft
thick and is underlain by the sandstones and shales of the Salt
Wash Summerville Formation.
The sites are on unconsolidated Colorado River alluvium, under-
lain by the Shire Member of the Hasatch Formation. In this area
the member is characterized by up to 1600 ft of thick impermeable
claystone and siltstone beds. Geologic structure includes the
Piceance Basin north and west of Rifle and the White River uplift
northeast. The Wasatch Formation dips 3 deg or less to west or
northwest at the site.
Surface Water
Hydrology
Flowing surface waters adjacent to or near the site consist of
the San Miguel River and intermittent streams that drain the
neighboring canyons. Waters have flowed onto the former pile
area from the diversion ditch along the southwestern border of
the site and from drainage at the northwest of the site. The
area has been inundated by flood waters since the tailings were
removed.
Surface water at the sites include drainage ditches, water-
accumulation ponds, and some marsh areas. Both sites are in the
floodplain of the Colorado River. The main channel has undergone
six major redirections in the past 100 years because of major
floods. Computed flows are 45,000 cfs for 100-year flood and
65,000 cfs for 500-year flood but, because of the wide floodplain
in this area, flood velocities would be on the order of 3 feet
per second.
Ground Water
Hydrology
The unconfined aquifers in the San Miguel River Valley consist of
waters within the recent valley alluvium. Except during flooding
season, the water table lies 3 to 10 ft below the former tail-
ings-subsoil interface. During an intermediate regional flood or
more severe floods, the water table would rise within the allu-
vium. Potential confined ground water aquifers consist of sand-
stone strata within the Morrison Formation and the sandstone
units within the Entrada Formation. The Summerville Formation
separates the Morrison Formation from the Entrada Formation and
prevents downward migration of water.
Both bedrock and alluvial groundwater subsystems are present.
The bedrock system, the Molina Member of the Wasatch is under
artesian pressure and probably provides a small recharge to the
alluvial system. At the old site alluvial ground water repre-
sents a small, nearly isolated system recharged by flow from the
river, precipitation, and return irrigation flows. A ground
water mound beneath the pile keeps the tailings saturated even
during periods of low water. At the new site the alluvial aqui-
fer is recharged by infiltration from the Colorado River, preci-
pitation, side-channel flow, and seepage from Rifle sewage faci-
lities.
Waste and Soil
Characteristics
The tailings were removed from the site and reprocessed. The
soil beneath the former tailings pile area is composed of allu-
vial deposits of the San Miguel River.
Materials include uranium and vanadium tailings, rubble, conta-
minated earth and stabilization cover. The tailings are on un-
consolidated Colorado River alluvium 16 to 21 ft thick at the old
site and 20 to 25 ft thick at the new Site.
-------
Table 3-2. SUHHARY DESCRIPTIONS OF IHACT1VE URAM1UH HILL TAILINGS SITES Cconfd)
Slick Rock, CO (Union Carbide, North Continent)
Louaan, ID
Location,
Topography
Tuo sites, the Union Carbide Corporation (UC) site and the North
Continent (NO site, about 0.9 mi apart. The sites are located
approxinately 25 ni north of Dove Creek, CO, and 3 mi northwest
of Slick Rock, CO, in the Dolores Eiver Valley.
The site is located approxinately 75 Bi northeast of Boise, ID,
in a pine-covered uountain valley in the Boise National Forest,
on a west-facing terrace of the Sawtooth Mountain Range. Drain-
age from the site is into Clear Creek .
Geology
i,
The sites are located on the flood plain of the Dolores River.
Bedrock consists of sedimentary strata: Navajo Sandstone at the
UC site and the Salt Wash Heaber of the Morrison Fornation at the
NC site. The bedrock strata dip gently to the northeast.
The site is located on a glacial terrace, incised by Clear Creek.
A lower river-laid terrace, on which a settling pond area was
constructed, is adjacent to the higher nillsite terrace. The
glacial terrace material is composed of deep sandy and loamy
soils, gravels, sands, boulders, and cobbles. The lower alluvial
terrace is river-run material. Igneous granite bedrock
(granodiorite), underlies the site.
Surface Hater
Hydrology
The flowing surface waters near the sites consist of the Dolores
River and three of its tributaries. An intermediate regional
flood (100-yr flood) or larger flood would inundate the base of
the piles and could erode part of the UC dike earth cover and
possibly the tailings themselves. The flow of flood waters
across the base of the NC site would not be as swift. Overland
flow across the piles is limited almost entirely to the precipi-
tation that falls on the piles.
Flowing surface waters near the site include Clear Creek, the
South Fork Payette River, and intermittent flow in ditches on the
site. Clear Creek, a swiftly flowing stream, intersects the
South Fork Payette River approximately 0.5 mi south of the site.
The lower terrace which borders the creek could be eroded by
flood waters of Clear Creek, with resulting undercutting and ero-
sion of the piles. Erosion at the site, aggravated by the steep
banks of the piles, has resulted in gullies up to 10 ft deep.
Ground Hater
Hydrology
Contamination of confined water systems theoretically is possible
because the bedrock strata are permeable and waters of the
Dolores River recharge the aquifers. The quantity of recharge
from the Dolores River would dilute any leaching from the tail-
ings piles.
Local aquifers are shallow and unconfined. Clear Creek and the
South Fork Payette River are gaining streams fed by flows from
unconfined ground waters. The terrace materials tend to filter
sediments from the waters and act as buffers to regulate overland
and subsurface flow. The interface between the unconsolidated
surficial materials and bedrock acts as the surface for lateral
ground water flow. Seeps and springs are common in the area,
particularly at the exposure of this interface.
Haste and Soil
Characteristics
The UC tailings are coarse-grained sand, while the NC tailings
are finer-grained with a clay content. Bulk densities run be-
tween 88 and 97 Ib/cu ft.
The materials are angular, dense, coarse-grained sands; some
gray and white, black (magnetite) and red (garnet). The under-
lying soil is mountain loam, nearly black in color, with gravelly
aggregates resulting froa glacial deposits in some locations.
-------
Table 3-2. SUMMARY DESCRIPTIONS OF INACTIVE URANIUM HILL TAILINGS SITES (cont'd)
Aabrosia Lake, NH
Shiprock, NH
Location,
Topography
The site is located in a valley 25 mi north of Grants and 85 »i
northwest of Albuquerque, NM. Mesas and steep cliffs surround
the valley and reach elevations about 2OO ft above the site.
The site is located on the Navajo Indian Reservation, on the
south side of the San Juan River at the town of Shiprock, NH.
The area is arid and desert-like, with low rolling hills and oc-
casional steep ridges and mesas.
Geology
The site is on a pediment sloping southuestuard from the base of
San Hateo Mesa. The underlying Hancos Shale bedrock dips gently
toward the northeast, opposite the direction of surface drainage,
and acts as a barrier to the downward and upward migration of
ground water in bedrock. Unconsolidated materials separating the
tailings pile from bedrock are composed of clays and silts, con-
tain some water, and do not exceed 15 ft in thickness.
The site is situated on an ancient river terrace adjacent to the
southwest bank of the San Juan River. Up to 10 ft of terrace de-
posits fom a layer between the Mancos Shale and the tailings.
The aaterials are poorly sorted and range in size from 12-in
boulders to sand- and silt-sized particles that are cemented to-
gether in places. The Mancos Shale directly below this alluvium
is at least several hundred feet thick.
Surface Water There are no perennial surface streams near the site. Dry washes
Hydrology drain near the site and some runoff can flow toward the site.
Surface waters near the site include ponded waters on the tail-
ings pile itself and near the mill. Tailings have been eroded
from the pile by storn runoff.
The elevated topography at the oillsite eliminates the possibi-
lity of flooding or erosion of the tailings by the waters of the
San Juan River. South and west of the tailings, the terrain is
relatively flat near the site. Drainage from the higher ground
farther to the south is carried to Dead Mans Wash, which empties
into the San Juan River about O.5 mi southeast of the site.
Ground Water The tailings lie on unconsolidated materials which contain sone
Hydrology unconfined ground waters. Seepage through the pile is possible.
The confined ground waters of the area are protected by Hancos
Shale fro» the downward flow of contaminants from the tailings
pile. The Dakota Sandstone underlies the Mancos Shale and is a
potential aquifer. The Westwater Canyon Sandstone Member of the
Morrison Formation is tapped as the major aquifer in the area,
which is unusual since it serves as the chief uraniu«-bearing
horizon of the vicinity.
The confined ground water aquifers underlying the site are pro-
tected against contamination by both an upward pressure gradient
and thick impermeable strata. There is a potential for further
contamination of the terrace gravel immediately underlying the
tailings piles if sufficient water is allowed to collect and
percolate through the piles.
Haste and Soil
Characteristics
The tailings are white to pink finely-ground sand with some clayi
bulk densities range from 100 to 108 Ib/cu ft. Material beneath
the site is a thin alluvial layer of clay and silt derived from
the surrounding highlands.
Materials include a combination of uranium and vanadium tailings,
dike material, rubble, and stabilization cover of pit-run gravel
Bulk densities range between 82 and 107 Ib/cu ft. The soil on
the site is a combination of decomposed shale and a conglomerate
of river-deposited sand and cobbles.
-------
Table 3-2. SUHHAKY DESCRIPTIONS OF INACTIVE UKAHIUH HILL TAILINGS SITES (confd)
Location,
Topography
Geology
I—1
o
Surface Hater
Hydrology
Lakevieu, OS
The site 13 located In Goose Lake Valley 96 mi east of Klamath
Falls, OR. Hountains surrounding the site on the east and west
reach elevations of 8,000 ft.
The Lakevlew site is located in an unconsolldated valley fill
consisting of clays, sands and gravels that overlie sedimentary
rocks of lacustrine and fluvial origin. The site is at the
eastern boundary of the Goose Lake Graben, uhich Is block-faulted
by northerly and northeasterly normal faults.
The surface eaters near the site consist of drainage ditches,
ponded water after rains, and an unnamed stream from Haamersley
Canyon that is routed between the tailings pile and the adjacent
evaporation ponds. There is no evidence that the stream flow has
eroded the tailings pile or the embankaents surrounding the eva-
poration ponds.
Canonsburg, PA
The site is located within the corporate Halts of the borough of
Canonsburg, PA. The site slopes to the east toward Chartiers
Creek.
The unconsolidated materials at the site are of fluvial origin.
Underlying these deposits are sediaentary strata of the Penn-
sylvanian Systea, consisting of sandstone with a little conglo-
merate, shale, liaestone, clay, and numerous beds of coal. The
site lies on top of the Conemaugh Formation, which is predomi-
nantly shale with abundant sandstone beds and some limestone,
clay, and coal.
Abundant surface waters in the area include several streams, nu-
merous intermittent drainages, and several reservoirs and ponds.
Surface waters in the vicinity of the site include Chartiers
Creek and several ditches which carry runoff. At a gauging sta-
tion in Carnegie, about 12 mi northeast of Canonsburg, the annual
average flow of Chartiers Creek was recorded at 287 cfs. The
estimated annual average flow of Chartiers Creek in Canonsburg is
between 90 and 130 cfs.
Ground Hater
Hydrology
Ground water occurs under confined and unconfined conditions.
There is a strong upward flow gradient from leaky artesian aqui-
fers in the thin, unconsolldated lacustrine sediments. Conta-
mination of the ground water is unlikely. A known geotheraal
area is located adjacent to Harner Mountain, and the surface
water temperature at Hunters Hot Springs, 1 mi northwest of the
site, is 212 F.
Confined ground-water systems in the Conemaugh Foraation under
the site occur largely in the sandstone beds with limited quanti-
ties in the bedding-plane passages and in joint planes of the
shales and limestones. Yields are variable and unpredictable but
generally range from small to moderate. A median yield for wells
in this aquifer is 5 gal/Bin. Yields large enough for industrial
or municipal purposes are difficult to obtain. Unconfined ground
water at the site is found in fill materials and in alluvial
deposits.
Haste and Soil
Characteristics
The uranium tailings are of a fine brown sand. The natural soil
on which the tailings rest is a rich dark brown-to-black loam.
Tailings have been stabilized in place.
-------
Table 3-2. SUHHARY DESCRIPTIONS OF INACTIVE URANIUM HILL TAILINGS SITES (confd)
Belfield, ND
Bounan, ND
Location,
Topography
The site is located about 19 mi uest of Dickinson, ND, on nearly
level land immediately south of the North Branch of the Heart
River. The Heart River, an interaittent strean, flows generally
uest to east in a channel 10 to 15 ft belou the general elevation
of the site.
The site is at the Griffin siding about 7 ni uest of Bowman. It
is on nearly level land near the head of Spring Creek, a part of
the Grand River drainage basin. An interaittent drainage to the
uest joins Spring Creek less than 0.5 mi southwest of the site.
(jo
I
Geology
Surface Water
Hydrology
The site is located on alluvial deposits of the Heart River uhich
are largely silt and clay uith a few beds of sand and gravel.
Underlying bedrock is poorly consolidated. A lignite bed occurs
at 50 ft depth. In many localities scoria beds are present, from
burned lignite beds.
The site is located on the south side of the north branch of the
Heart River. In the vicinity of the site, the river is an inter-
mittent streaa draining only a small area. During summer months
there may be areas of stagnant water in the streaabed. Surface
flows arise only from rainfall directly on the site. Precipita-
tion on the site drains either to the Heart River or to ponds on
the site.
The site is underlain by the Bullion Creek Formation, sometimes
called the Tongue River in this area. The formation consists of
light layers of silt, clay, and sand with interbedded sandstone,
lignite, baked clay, and limestone.
The site is located 1 mi north of Spring Creek in the headwaters
of the North Fork of the Grand River, a tributary of the Missouri
River. A small intermittent drainage runs along the uest side oi
the site and joins Spring Creek 0.5 ui southuest of the site.
Precipitation tends to pond in local low spots and generally eva-
porates uith some infiltration into the clayey-silty soils on the
site. Numerous small reservoirs in the vicinity of the site are
generally used for stockwater, irrigation, and recreation.
Ground Water
Hydrology
There are four najor usable aquifer systems underlying the site.
The uppermost, the Sentinal Butte Formation, outcrops much of the
area and supplies rural livestock and domestic wells. , The next
lower system, the Ludlou and Tongue River, Is probably comprised
of several aquifers. The upper aquifers may be unconfined, are
interconnected uith and recharge the louer part of the system.
The Upper Hell Creek and Lower Cannonball-Ludlow Formation form
the third aquifer system and is not extensively tapped in this
area. The lowermost system, the Fox Hills and Basal Hell Creek
Formation, is not heavily used in this area but is tapped by tuo
Belfield city uells. The minimal water in the alluvial deposits
on the Heart River in this area may contribute to local wells.
The water table is about 40 ft below the surface.
There are four major usable aquifer systems beneath the site.
These include from highest down, the Upper Ludlow and Tongue
River Aquifer, Middle Ludlow Aquifer System, Upper Hill Creek anc
Louer Ludlou Aquifer System, and the Fox Hills and Basal Hill
Creek System. 'The upper three are locally interconnected, with
recharge from precipitation and seepage from surface waters and
are used locally for domestic and stock purposes. The louer
aquifer. Fox Hills and Basal Hill Creek System, is recharged by
percolation from overlying beds, is most reliable and serves
municipal needs.
Haste and Soil
Characteristics
No mill material is present! all ash from the kiln was shipped
to Rifle, CO. However, radiation measurements showed that most
of the surrounding soil at the site is contaminated to depths of
6 to 12 in, locally to 4 ft. The soils present on the site are
Savage silty clay loams; soil and subsoil are 2 to 3 ft thick.
Hill materials (ash from the kiln) was collected and shipped to
Grants, NH, for further processing. The soil at the site is con-
taminated to depths of about 3 ft. Soils are silts and clays up
to 7 ft in depth, with sands below that. Bedrock is not consoli-
dated and is less than 2O ft below the surface, at which depth a
coal bed is located.
-------
TABLE 3-5. AVERAGE CONCENTRATION OF ELEMENTS FOUND IN INACTIVE URANIUM MILL TAILINGS (a)
(in ppm)
GO
I—>
CO
ELEHENT
As Ba
Cd
Arsenic Barium Cadmium
Tailings Pile
Arizona
Monument Valley
Tuba City
Colorado
Uurango
Grand Junction
Gunnison
fiaybell
Naeurita ,
New Kitle
Old Rifle
Slick Rock NC
Slick Rock UC
New Mexico
Ambrosia Lake
Shiprock
Utah
Green River
Mexican Hat
Vitro Uranium^0'
Vitro Vanadium^0'
Wyoming
Spook
Riverton
"Typical" Soil^J
^a^ Adapted from G. Markos
^Table 3-1 (1 pCi/g = 1
1.5
82 86
0.80 82
14 121
254 66
1.5 18
59 - 172
4.2 100
3.7 155
34 453
6.6 134
2.6 96
0.004
1.9 73
63 12
210 2130
244 3860
87 46
161 64
6 500
and K.J. Bush,
x 10~°ppm, for
-
4
0.20
1.6
0.26
0.09
0.07-
1.1
8.7
0.027
0.074
3.6
-
0.40
0.70
-
-
0.37
0.32
0.06
Cr .
Chromium
-
6
8.8
29
5.2
9.3 ;
- 3-5 y
55
20
4.9
3.4
8
-
17
1.0
1010
2030
26
23
100
Cu
Copper
-
1160
95
14
30
3.1
54
8
18
35
17
58
-
102
488
310
1080
14
21
20
"Physico-Chemical Processes
Ra-226) .
Fe
Iron
-
7230
62
1170
20800
2100
16400
807
8250
6540
4080
90
—
1210
3650
31100
213000
15299
21800
38000
in Uranium
Pb
Lead
—
812
62
50
137
13
48-
187
38
1250
29
—
—
121
40
3060
350
2.5
3.2
10
Hg
Mercury
—
0.001
0.87
0.026
—
0.09
• - — -
0.001
0.25
109
0.074
0.002
—
0.001
—
—
—
—
~
0.03
Mill Tailings and
Se Ag
Selenium Silver
0.064 —
10 6
1.2 1.2
3.1 0.72
1 3.8
13 0.15
0.47 1.1
1.9 1.4
2.7 0.46
0.76 1.7
2.2 0.57
68 0.15
0.18
231 0.070
6 1.0
0.022
0.066
262 2.2
391 2.4
0.2 0.1
Their Relationship
U
Uranium
60
370
480
180
90
120
500 -
240
380
80
50
210
120
60
140
180
50
130
70
1.0
V
Vanadium
1850
620
3900
1760
80
120
2890
3990
520
620
1480
1590
330
1390
1350
100
830
350
240
100
to Contamination"
Zn Ra-226W
Zinc Radium
(x 10"6)
50
249 920
304 700
45 780
120 420
17 274
75
31 870
359 1000
21 780
21 690
47 640
700
21 810
57 780
340
350 900
31 340
38 560
50 1.5
(MacSla)
different parts of the Vitro Site, Salt Lake City, Utah.
-------
TABLE 3-8. GROUND HATES HATSIX
SJTg_GRQyNJ::HATER_CHARACTERISTICS
AREAL AND VERTICAL EXTENT
OF GROUND-HATER CONTAMINATION
u>
i
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING HATER STANDARDS
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUME(S)
AHBEQSIA_LAKEA_MH
Primarily in alluvium & Tres
Heraanos-Ci Hay eventually dis-
charge into Hestuater Canyon.
Approximate volumes:
Alluviun - 450 Billion gal.
Tres H.C - 225 Billion gal.
Host samples exceed standards
for Co,Hn,Ho,Radiua,5O4, and TDS
A snail # of saales exceed stds
for As,B,Cd,Cl,Cr,F,G Alpha,Fe,
N03,pH,Se,Ag, and U.
The alluvium and Tres Heraanos-C
sandstone were probably unsat^
urated prior to aining and
Billing.
None in alluvium & Tres Heraanos
sandstone:Hestuater Canyon sand-
stone is major water supply.
Eventual discharge to Bine
shafts and vents into Hestwater
Canyon Sandstone.
Sentinel Butte Formation, extent
not yet determined.
Not yet deterained.
High concentration of SO4, TDS
Stock uells, soae domestic
uells aostly for purposes other
than drinking.
Possible discharge to the Heart
River.
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
HATER QUALITY AT ALTERNATE SITE
Because only unused and unusable
grounduater has been and Hill be
significantly impacted there is
no need for inst. controls.
None.
N/A
N/A
State of North Dakota requires
well permits for domestic uells.
Bull creek or stabilization
with tailings at Bowman, ND.
Bull Creek - 50 feet
Bouaan - 10 to 15 feet
Bouman - high SO4, TDS
Bull Creek - unkoun, probably
similar to Belfield and Bouaan
EXPECTED IMPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE.
N/A
Grants, NM - 8 Biles.
Minimal.
Belfield, ND - 1/2 mile.
-------
TABLE 3-6. GROUND MATER MATRIX Ccont'd)
SITJ_GROyNJrWATER_CHARACTIRISTICS
AEEAL AND VERTICAL EXTENT
OF GROUND-HATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING WATER STANDARDS
NATURAL GROUND-WATER QUALITY
EXISTING USE OF GROUND WATER
FATE OF THE PLUME(S)
!SHHAH*_ND
Tongue River Formation, extent
not yet determined.
Not yet quantified.
High concen-tration of S04,TDS
Stock wells and a feu domestic
wells, not normally used for
drinking.
To be determined.
Onsite in alluvium. Hay extend*
into upper shale/limestone bed-
rock. Some indication of alight
contamination.
Volume approx. 1OO million gal.
Cosntituents above standards in
onsite, alluvial waters are:
C1,S04, and TDS.
Background alluvial uater sample
NO3 exceeds standard.
Limited use, primarily for
gardening. Note: More data will be
forthcoming from S&M oonitoring.
Probably discharging to Chartier
Creek although there maybe aone
underflow in shallow bedrock.
00
to
o
FEASIBILITY OF INSTITUTIONAL
CONTROLS
State of North Dakota requires
uell permits for domestic uells.
High feasibility given limited
use & discharge of contamination
to Char-tiers Creek at site bound
ALTERNATE DISPOSAL SITE
DEPTH TO WATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON WATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS SITE.
Bull Creek, approximately
50 Biles north of Bowman.
5O feet.
Unknown, likely to be similar to
the background water quality at
Bowman and Bel field.
Minimal.
Bowman, ND - 7 miles.
N/A
N/A
N/A
N/A
Canonsburg, PA - in town.
-------
TABLE 3-6. GROUND WATER MATRIX (cont'd)
SITE GROUND-WATER_CHARACTERISTICS
AREAL~AND~VERTICAL~IXTENT
OF GROUND-HATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING WATER STANDARDS
NATURAL GROUND-WATER QUALITY
EXISTING USE OF GROUND WATER
FATE OF THE PLUME(S)
DURANGg±_CO
DUR01 (piles) - alluviums approx-
50 acres x 2O-30 feet deep.
DURO2 (ponds) - alluviums approx-
55 acres x 3O-40 feet deep.
Henefee Fm. one well 50-70' deep
DUR01 - alluviums CL-4x, Fe-2x,
As- lOOx,Se-lOOx,S04-15x,U(6.2mg/
DUR02 - alluviums Cl-5x,As-5x,
Se-40x, S04-115X, U(2.4mg/L)
DUR02 - Menefee Fm: Cl-6x, Se-2x
slightly elevated Cl, Fe, TDS, U
but drinking water quality
No current users within two
miles downgradient.
Discharge to Animas River within
100 to 500 feet of the piles and
ponds.
K>
_._
Unconfined system (Dewesville/
Conquista) 7OO ac x 60-70 feet.
approx. 4 billion gallons.
Semi-confined (Dilworth)s
contamination in 2-4 wells, 120
to 150 feet deep.
Unconfined system: Cl-23x,Fe-40x
Mn-200x,S04-20X,TDS-26X,Ra-226
(lOOpc i/L),U(67mg/L)
Semi-confined systems Cl-4x,
S04-8x,TDS-15x,U(3.2mg/L).
SO4,Cl,Fe,Mn,TDS exceed drinking
water stds, U= 1OO-300 ppb.
Four livestock wells within two
miles. No domestic consumption.
Discharge to San Antonio R. NE
of site in 150 to 200 years.
Discharge to Borrego Cr. SW of
site in 30O to 4OO years.
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO WATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON WATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS SITE
Have been recommended to the
state.
Bada Canyon
20 to 4O feet
S04, TDS, Fe, Mn exceed
drinking water standards.
Minimal; shallow system
discharges to Animas River
within two miles of the site.
Durango, Colorado -
1.5 ailes NE of Bada Canyon site
State of Texas requires well
permits for domestic wells.
Not evaluated.
N/A
N/A
N/A
Falls City, Texas
of tailings site.
- 9 miles NE
-------
TABLE 3-6. GROUND HATER MATRIX (cont'd)
to
§ITJJ5RgyND-HATER_CHARACTERISTICS
AREAL~AND~VEBi?ICAL~IXTlNT
OP GROUND-HATER CONTAHINATION
NATURE AND DEGREE OF
CONTAHINATION RELATIVE TO
DRINKING HATER STANDARDS
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUHE(S)
G?AND_jyNCTIONt_CO
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
HATER QUALITY AT ALTERNATE SITE
EXPECTED IHPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS SITE
Proa the site to the vest, up to
1/2 Hi downgradient of site in
alluviua. SOB® entats, aay enter
Dakota Ss 8 subcrop 1/2 mi west.
Relative to atds and background,
the 5 critical contaminants are:
Cl,F,Fe,S04, and Cd,
Host background saaples exceed
standards for Cl,Fe,Hn,304,8. TDS
No knoun use of alluvial or
Dakota sandstone uater.
Discharge to the Colorado River
or enter the Dakota SS and dis-
perse through space and time.
Highly feasible: DThe site is
w/in a municipality. 2)Contaain-
ated uater has not been used &
has liaited value.
Cheney Reservoir
Approxiaately 30 feet.
Brackish. Seasonally perched.
No impact on any potential water
resource.
Grand Junction, CO - in town.
Brown's Hash Aluvium - <= 9 ac
x 7 feet
Cedar Mountain Fa. - <= 9 ac
x 25 feet.
Alluvium - N03-lix, NH4(4Dag/L),
UC1.19ag/L),Hn-10x.
Cedar Htn. FB. - N03-llx,
NH4(30ag/L), UCl,86mg/L),
Hn-25x
Not suitable for drinking uater.
High cone, of TDS, SO4, Cl, Se, F.
None.
Alluvium - discharge into Brown's
Hash approx 4OO feet froa pile.
Cedar Htn. FB. - no discharge
point identified. Pluae will
disperse in this aquifer.
State of Utah requires well
peraits for domestic use.
Recommended stabilization on site
N/A
N/A
N/A
Green River, UT
rt-f o 4 + A
- 1 mile NH
-------
TABLE 3-6. GROUND HATES MATRIX (confd)
SITE_GROUND-HATER CHARACTERISTIOS
ARlAL AND~vlRTICAL~EXTlNT
OF GROUND-HATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING HATER STANDARDS
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUME(S)
GUNNISON, CO
NJ
approximately 1 sq. Bile;
depth (thickness) approx. 10O ft
Voluee approx. 2 billion gal.
Ud.l ag/L>, N03-3x, S04-7x,
Se-lOx, Fe-5Ox (based on max.
values.)
Potable, TDS-300 mg/L.
Domestic.
Disperse to below drinking
water standards. Discharge to
Gunnison R. & Tonichi Creek.
Approx 1/4 to 1/2 Bile doungrad-
ient to 5O-75 ft depth in uucon-
solidated deposits.
Volume approx. 3 billion gal.
As,B,Cl,F,Mn,S04,& TDS standards
are exceeded in nany onsite and
doungradient shallow sample. Cd
Fe, & pH are exceeded in a feu
instances. The exceedances are
rarely greater than 1O tines std
Non-geothermal background is
potable,except Mn std exceeded
in some cases. Geotherual bckgrd
exceeds std for As,F,& TDS.
Considerable use for domestic,
agricultural,Municipal,industry.
Most use is at depth >1OO ft.
Disperse & dilute as the
contaminants move doungradient
in the unconsolidated deposits.
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
HATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
The state of Colorado requires
well permits for domestic use.
East Gold Basin.
10O - 20O feet.
Potable, TDS-600 ng/L.
Under evaluation.
Gunnison, CO - 1OOO ft.
The contaminant levels are lou
enough that only shallow ground
water close to the site may need
to be controlled. Therefore
institution controls are feasible
Collins Ranch.
Greater than 3O feet.
Potable without treatment.
Minimal impact; i.e.,stds should
not be exceeded at closest well
for at least 1000-yrs.
Lakeview, OR - in town.
-------
TABLE 3-6. GROUND WATER HATHIX Ccont'd)
§ITg_GigyND-WATER_CHABACTERISTICS
ARBAL AND VERTICAL EXTENT
OF GROUND-WATER CONTAMINATION
iQHHANx_ID
To be determined.
HAYBELLA_CO
To be determined in FY87.
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING WATER STANDARDS
NATURAL GROUND-WATER QUALITY
EXISTING USE OF GROUND WATER
To be determined.
FATE-OF-THE PLUHE(S)
Drinking water quality
TDS < 250 mg/L.
Surface and ground water used
for drinking uater supplies.
To be deterained.
U, N03, S04, Cl, and possibly
trace elements (As, Se, Mo) are
constituents of tailings seepage
Site hydrogeological conditions
are not complete & solutes that
exceed Standards not yet known.
Possible drinking uater quality.
TDS as high as 12OO Mg/L.
Ground uater within the alluvium
used for drinking uater supply
in Haybell. Brouns Park Fra. is a
regional source of drinking
water supply.
To be determined.
00
to
FEASIBILITY OF INSTITUTIONAL
CONTROLS .
ALTERNATE DISPOSAL SITE
DEPTH TO WATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON WATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
To be determined.
Possibly along Highway 21, east
of the tailings, not yet
positively identified.
Unknown..
Unknown, probably similar to
Unknown.
Louman, Idaho - 1/4 mile.
State of Colorado requires well
permits for domestic wells.
Johnson Pit — located approx.
0.25 mile south of tailings site.
Unknown.
Unknown, possibly similar to
Maybe 11,.
Unknown.
Maybell, CO - 7.3 miles SW.
-------
TABLE 3-6. GROUND NATES MATRIX (cont'd)
SITE GROUND-HATER_CHAJACTERISTICS
AREAL~AND~VERTICAL~ixfEMT
OF GROUND-HATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING HATER STANDARDS
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUME(S)
300 acres X 40 feet.
Mn-26x,NO3-2x vS05-9x,TDS-8x
UC0.43 mg/L)
High cone, of SO4 and TDS;
unsuitable for drinking water.
None.
Seepage into Gypsum wash and
movenent to San Juan R. No
contamination in the river.
MONyHENT_VALLEYi_AZ
570 acres x 80 feet.
NO3-24x,S04-6x,U(O.03 »g/L>
Mn-12x,TDS-7x
Drinking water quality
TDS < 500 «g/L.
A few handpunp wells for local
residents.
Natural dispersion, 20 to 20O yr
to reach background. Possibly
some discharge to Cane Valley
Hash during storms.
oo
to
Ol
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
HATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
Navajo Tribe requires well
permits for domestic wells.
Not evaluated.
N/A
N/A
N/A
Mexican Hat, Utah - one mile.
Halchita, Utah - O.25 Biles.
Navajo Tribe approves/records
all wells.
Yazzie Mesa approx. 1/2 mile
southwest of the tailings.
160 feet.
Drinking water quality ..-••-.-
TDS < 500 mg/L.
Minimal; water table separated
from tailings by relatively
impermeable Moenkopi Formation.
Mexican Hat, Utah.
-------
TABLE 3-6. GROUND HATER MATRIX (cont'd)
(JO
NJ
STTE GRgiJND-HATER_CHARACTBRISTIC5
AR!AL~AND VERTICAL'EXTENT
OF GROUND-WATER CONTAHINATION
NATURE AND DEGREE OF
CONTAHINATION RELATIVE TO
DRINKING HATER STANDARDS
HATURITAj^CO
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUME(S)
Alluvium - 73 ac x 20 feet.
95 million gallons.
Fe-3x,Hn-65x,S04-4x,
TDS-4x,UC2.S»g/L)
Marginally suitable for drinking
water. S04 and TDS slightly
above standards.
None.
Discharge into adjacent San
Hlguel River.
RIFLEt_CO
RFO - alluviua, 9 ac x 30 feet
RFN - alluvium, 4OO ac x 30 feet
RFN - Haaatch F*., 150 ac x 50 ft.
RFO - alluvium S04-10x; TDS-10x{
U (2.08 mg/L)
RFN - alluvium N03-19x; S04-100x
TDS-BOx; U(1.3mg/L); Ho(12.0*g/L
NH4(6100 mg/L)
RFN - Hasatch 304-104x5 NO3-2x;
TDS-7Bxt NH4(290O mg/L); U(0.76
Ho(5 mg/L)
High cone, of S04, Hn, Fe,
NH4, Cl, TDS. Unsuitable for
drinking water.
Wasatch aquifer not used.
Alluvial sq. used for livestock
and irrigation. City uses
Colorado River water.
Natural seepage to river adjacent
to both sites. Return to backgrn
in a minimum of 2yrs for RFO and
45yrs for alluvium at RFN.
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
HATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
State of Colorado requires well
permits for domestic wells.
Not evaluated.
N/A
N/A
N/A
Naturita, Colorado - 2 miles.
State of Colorado requires well
permits for domestic wells.
Estes Gulch, ground water not
used in a 2 mi. radius of site.
> 280 feet through Wasatch.
Unknown.
None. 800 yr travel time to
first possible ground water.
Rifle, Colorado - Tailings
-------
TABLE 3-6. GROUND WATER MATRIX (confd)
SITE_GROUND-WATER_CHARACTER1STICS
ARiAL AND~VERT?CAL EXTENT
OF GROUND-MATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING WATER STANDARDS
NATURAL GROUND-WATER QUALITY
EXISTING USE OF GROUND WATER
FATE OF THE PLUME(S)
From site to the Little Wind
riverCapprox.1/2 mile) through
the alluvium & unconfined SS
(approx. 20 ft thick).
Volume approx. 1 billion gal.
Key contaminants w/ exceedence
of stds are Fe,Hn,S04,Cl,and a
feu samples of exceedences for
radium and selenium. U as high
as 2 mg/L, & Mo max is 4 mg/L.
Brackish in alluvium.
Minor stock watering.
Discharge to Little Wind River.
From site possibly to the Jordan
River and Hill Creek in the
unconfined aquifer to depth of
approx. 3O to 4O feet.
Volume approx. 1.5 billion gal.
Key contaminants are: As, Cl,
Fe, W04, TDS, and Gross Alpha.
None in unconfined system.
Discharge tot he Jordan River
and Mill Creek.
CO
I
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO WATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON WATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
High feasibility because limited
use or potential use of alluvial
ground water.
American Nuclear Corporation in,
Gas Hills.
Unknown.
Unknown.
Unknown.
Riverton, WY - 3 miles.
High feasibility due to lack of
existing & potential use and
availability of public water
supply.
dive, Utah.
Approximately 3O to 40 feet.
Brackish.
None on potential water resource.
South Salt Lake - in town.
-------
TABLE 3-6. GROUND HATER MATRIX (confd)
_ CHARACTERISTICS
AREAL AND vlRTICAL EXTENT
OF GROUND-WATER CONTAHINATION
NATURE AND DEGREE OF
CONTAHINATION RELATIVE TO
DRINKING WATER STANDARDS
NATURAL GROUND-WATER QUALITY.
EXISTING USE OF GROUND WATER
FATE OF THE PLUHE(S)
SHIPROCKi_ NH
oo
N3
C3
Beneath site & below aite in
floodplain alluvium. Depth is 10
to 30 ft, to top of competent
Hancoa Shale. Floodplain vol.
Onsite approx. 850 Billion gal.
Significant exceedences of stds
for Cl,Cr,Hn,N03,Se,S04,and TDS,
UC3.5 Bg/L).
On escarpnent, poor to non-
existent; on floodplain, slight
exceedence of SO4 & TDS stds.
Some doaestic use and potential
Municipal use of floodplain
ground water and San Juan River
water.
Appears to be relatively stag-
nant but eventually should dis-
charge to the San Juan River.
NC Site - 23 acres x 2O feet.
30 Billion gallons.
UC Site - 17 acres x 20 feet.
23 Billion gallons.
NC site* Fe-9x,Hn-9x,S04-5x,
TDS-5x,U(2.5ng/L)
UC site: N03-34x,Cl-l.lx,Fe-8x,
Hn-5Ix,S04-7x,TDS-Bx,
UC0.09 Bg/L).
Alluviua - high cone, of Hn, S04
TDS. Not drinking water quality.
Navajo Ss. - drinking water qual.
No use of alluvial ground water.
Navajo aquifer supplies all
needs.
Discharge into adjacent Dolores
River.
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO WATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IHPACT ON WATER
QUALITY AT ALTERNATE SITE
NAHE OF NEAREST CITY/DISTANCE
FROH TAILINGS PILE
Could be fenced, plus the
Navajo Tribe has a well permit
requirement.
N/A
N/A
N/A
N/A
Shiprock, NH - in town.
State of Colorado requires well
permits for domestic wells.
Disappointment Valley.
approx. 40 feet below land
surface in Mancos Shale.
High TDS reported. Unsuitable
for drinking water.
Not evaluated.
Naturita, CO - approx 46 Biles.
-------
TABLE 3-6. GROUND HATER MATRIX (cont'd)
SI TE_GROU NDrHATER_CHARACTER ISTICS SPOOK JL_HY
AREAL~AND VERTICAL~EXTENT " To be determined in 1987.
OF GROUND-WATER CONTAMINATION
NATURE AND DEGREE OF
CONTAMINATION RELATIVE TO
DRINKING HATER STANDARDS
NATURAL GROUND-HATER QUALITY
EXISTING USE OF GROUND HATER
FATE OF THE PLUHE(S)
To be determined in 1987.
Drinking uater quality.
Domestic, agricultural, and
livestock use.
To be determined in 1987.
TUBA_CITYi_AZ
110 acres x 110 feet of the
Navajo Sandstone.
Approx. 1.2 billion gallons.
NO3-34x$ S04-9x; U-O.45 mg/L;
Fe-2x; Mn-13x; TDS-12x.
Drinking uater quality.
TDS < 5OO mg/L.
Municipal uell field for Tuba
City is 5 mi. from site. One
domestic uell is 1.5 mi. cross-
gradient.
Discharge to Hoenkopi Hash
10,000 feet from leading edgee
of plume. First arrival of
plume at Hash in 100 years.
GO
I
to
vD
FEASIBILITY OF INSTITUTIONAL
CONTROLS
ALTERNATE DISPOSAL SITE
DEPTH TO HATER TABLE AT
ALTERNATE DISPOSAL SITE
WATER QUALITY AT ALTERNATE SITE
EXPECTED IMPACT ON HATER
QUALITY AT ALTERNATE SITE
NAME OF NEAREST CITY, DISTANCE
FROM TAILINGS PILE
State of Wyoming.
None.
N/A
N/A
N/A
Navajo Tribe approves/records
all uells. i
None. •
N/A
N/A
N/A
Douglas, HY - approx. 45 miles. Tuba City, AZ - approx. 5 miles.
-------
REFERENCES
1. Ford» Bacon & Davis Utah, Inc. April 1981.
Inactive Uranium Mill Tailings - Vitro Site,
Engineering Assessment of
. Salt Lake City Utah.
DOE/UMT-0102, prepared for the U.S. Department of Energy by Ford, Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
2. Ford, Bacon & Davis Utah, Inc. June 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Durango Site, Durango, Colorado^
DOE/UMT-0103, prepared for the U.S. Department of Energy by Ford, Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
3. Ford, Bacon & Davis Utah, Inc. July 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Grand Junction Site, Grand Junction
Colorado.DOE/UMT-0105, prepared for the U.S. Department of Energy by
Ford, Bacon & Davis Utah, Inc., Salt Lake City, Utah.
4. Ford, Bacon & Davis Utah, Inc. July 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Naturita Site, Naturita, CoToFadoT—
DOE/UMT-0112, prepared for the U.S. Department of Energy by FordT~Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
5. Ford, Bacon & Davis Utah, Inc. July 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Shiprock Site, Shiprock, New Mexico.
DOE/UMT-0104, prepared for the U.S. Department of Energy by ford, Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
6. Ford, Bacon & Davis Utah, Inc. August 1981. Engineering Assessment of
Inactive Uranium Mill Tailings -New and Old RTfTe Sites, Rifle
Colorado.DOE/UMT-0108, prepared for the U.S. Department of Energy by
Ford, Bacon & Davis Utah, Inc., Salt Lake City, Utah.
7. Ford, Bacon & Davis Utah, Inc. August 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Riverton Site, Riverton, Wyoming.
DOE/UMT-0106, prepared for the U.S. Department of Energy by FordT Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
8. Ford, Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Gunnison Site, Gunnison, ColoraaoT
DOE/UMT-0107, prepared for the U.S. Department of Energy by FordT~Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
9. Ford, Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Lowman Site, Lowman, Idaho.DOE/UMT-
0118, prepared for the U.S. Department of Energy by Ford, Bacon & Davis
Utah, Inc., Salt Lake City, Utah.
10. Ford, Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Maybell Site. Maybe11 , Colorado!
DOE/UMT-0116, prepared for the U.S. Department of Energy by Ford", Bacon &
Davis Utah,. Inc., Salt Lake City, Utah.
3-30
-------
11. Ford, Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Mexican Hat Site, Mexican Hat, Utah.
17,
DOE/ UMT-0109, prepared for the U.S. Department oT
Davis Utah, Inc., Salt Lake City, Utah.
Energy by Ford, Bacon &
12 Ford, Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Slick Rock Sites, Slick Rock, Colorado.
DOE/UMT-0115, prepared for the U.S. Department of Energy By Ford, Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
13 Ford Bacon & Davis Utah, Inc. September 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Tuba City Site, Tuba City, Arizona.
1I1QL.V.IVC \J* dill Win iii i ' iv» ' ' ' *' j *" • -" ~ ** •*_ •"
DOE/UMT-0120, prepared for the U.S. Department of Energy by For
Davis Utah, Inc., Salt Lake City, Utah.
d, Bacon &
14 Ford Bacon & Davis Utah, Inc. October 1981. Engineering Assessment of
Inactive Uraniucn Mill Tailings - Falls City Site, Falls City, Texas.
DOE/UMT-0111, prepared for the U.S. Department of
Davis Utah, Inc., Salt Lake City, Utah.
Energy by Ford, Bacon &
15 Ford Bacon & Davis Utah, Inc. October 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Lakeview Site, Lakeview, Oregon.
DOE/UMT-0110, prepared for the U.S. Department of Energy by Ford, Bacon
Davis Utah, Inc., Salt Lake City, Utah.
16 Ford, Bacon & Davis Utah, Inc. October 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Monument Valley Site. Monument Valley,
—--- "-= = ^ -f Energy by
r u i u $ u a *-• w 11 IA L/WVI»J w w ««> 9 .•. i. v • >*• — — -- - -*•- —-
Inactive Uranium Mill Tailings - Monument Valley Site. Mon
Arizona.DOE/UMT-0117, prepared for the U.S. Department o
Ford, Bacon & Davis Utah, Inc., Salt Lake City, Utah.
Ford Bacon & Davis Utah, Inc. October 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Philips/United Nuclear Site, Ambrosia
EakeT New Mexico. DOE/UMT-0113. prepared for the U.S. Department 01
Energy by Ford, Bacon & Davis Utah, Inc., Salt Lake City, Utah.
18 Ford Bacon & Davis Utah, Inc. October 1981. Engineering Assessment of
Inactive Uranium Mill Tailings - Spook Site, Converse County, Wyoming.
DOE/UMT-0119, prepared for the U.S. Department of Energy by Ford, Bacon &
Davis Utah, Inc., Salt Lake City, Utah.
19. Ford, Bacon & Davis Utah, Inc.
Inactive Uranium Mill Tailings
the
November 1981. Engineering Assessment of
- Bel field Site, Bel field
DOE/UMT-0122, prepared
Davis Utah, Inc., Salt
for the U.S. Department
Lake City, Utah.
South
of Energy by Ford,
Dakota.
Bacon &
20. Ford, Bacon & Davis Utah, Inc.
Inactive Uranium Mill Tailings^
November 1981
- Bowman Site,
. Engineering
Bowman, South
Assessment of
DOE/UMT-0121, prepared
Davis Utah, Inc., Salt
for the U.S. Department of
Lake City, Utah.
Dakota.
Energy by Ford, Bacon
3-31
-------
21. Douglas, Richard L., and Joseph M. Hans, Jr. August 1975. Gamma
ladiation_Survexs_at_^nactive_Uranium_Miii_Sites. ORP/LV-75-5,
prepared for the U.S. Environmental Protection Agency, Office of
Radiation Programs - Las Vegas Facility, Las Vegas, Nevada.
22. Young, J.K., L.W. Long and J.W. Reis. April 1982. Environmental
Factors_Affecting_Long-Term_Stabil.izatio
Covers_f or_Uranium_Mill._Taiiings. NUREG/CR-2564, prepared for the
U.S. Nuclear Regulatory Commission by Pacific Northwest Laboratory,
Richland, Washington.
23. Pacific Northwest Laboratory. January 1984. Estimated_Pop_ul.ation
MlSE-Uranium_Tailings. PNL-4959/UC-70, prepared for the U.S.
Environmental Protection Agency by Pacific Northwest Laboratory,
Richland, Washington.
24. U.S. EPA. October 1982. Finai_Environmental._Imp_act_Statement_f or
SŁS§.di.ai._Action_Standards_f or_inactive_Uranium_Prgcess_ing_Sites
11Q.CFR1.92).. EPA-520/4/82/013-1 , Office of Radiation Programs, EPA,
Washington, D.C.
25. U.S. DOE. January 7, 1987. Uranium_Mil.i_TaiiinŁs_Remedial._Action
Pr o j.ect_Ground_Water_Matr i x.
3-32
-------
CHAPTER 4
COMPILATION AND ANALYSIS OF GROUNDWATER DATA FOR 14 SITES
4.1 INTRODUCTION
Groundwater quality data for 14 Uranium Mill Tailings Remedial
Action .(UMTRA) Project sites are analyzed in this chapter. The
14 UMTRA sites are:
Ambrosia Lake, New Mexico
Canonsburg, Pennsylvania
Durango, Colorado
Grand Junction, Colorado
Green River, Utah
Gunnison, Colorado
Lakeview, Oregon
Mexican Hat, Utah
Monument Valley, Arizona
Rifle, Colorado
Riverton, Wyoming
Salt Lake City, Utah
Shiprock, New Mexico
Tuba City, Arizona
This task analyzes the groundwater quality data collected from
wells on the sites and from wells surrounding the sites. These
data have been compared to the standards given or referenced in
Table A of 40 CFR 192.32(a), which are as follows:
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha Particle
Activity (including radium-226
but excluding radon
uranium)
Lead
Mercury
Combined radium-226
and radium-228
Selenium
Silver
Maximum Concentration
0.5 mg/1
1.0 mg/1
•0.01 mg/1
0.05 mg/1
15.0 pCi/1
0.05 mg/1
0.002 mg/1
5.0 pCi/1
0.01 mg/1
0.05 mg/1
These comparisons are in Table 1 for each of the 14 sites.
4-1
-------
In addition to the constituents listed above, six pesticides
were also referenced in 40 CFR 192.32 (a). No water quality
comparisons were performed for endrin, lindane,
methoxychlor, toxaphene, 2,4-D, or 2,4,5, TP. Water samples
from the sites were rarely analyzed for these pesticides.
These pesticides were undetected in the occasional samples
that were analyzed.
Three additional water quality comparisons beyond those in
Table A of 40 CFR 192.32(a), but related to leachate from
uranium mill tailings, are:
Constituent
Molybdenum
Uranium
Nitrate (nitrogen)
Maximum Concentration
0.10 mg/1
30 pCi/1 (0.044 mg/1)
10 mg/1
These^comparison are in Table 2 for each of the sites.
Also in Table 2 are comparisons to EPA primary and secondary
drinking water standards not contained in Table 1.
A summary of the water quality data has been prepared for
each site. The tabular data are presented after each site
summary. The site summaries discuss the key contaminantis
and their significance of occurrence within the context of
the site hydrogeologic setting and local groundwater use.
The fate of the contaminant plume was modeled at 9 of the
sites. The results indicate natural reduction of the mobile
contaminants (nitrates, chlorides, sulfates, and total
dissolved solids) to standards or background levels in 100
years or less at 6 of the 9 sites modeled. The longest
period indicated was for the Mexican Hat site where over 500
years will be required for natural flushing of the mobile
contaminants. Purging of the attenuated contaminants
(uranium, molybdenum, and other metals) typically takes 2 to
3 times as long and only at one site are levels predicted to
reach standards or background levels within 100 years. At 6
of the sites it appears that purging' of these may be accom-
plished within 300 years.
4-2
-------
4.2 AMBROSIA LAKE, NEW MEXICO - SUMMARY OF WATER QUALITY
The saturated formations at the Ambrosia Lake site include
the alluvium, Tres Hermanos Sandstones, Dakota Sandstone and
Westwater Canyon Sandstone. Prior to mining and milling
activities, it appears that the alluvium and Tres Hermanos-C
Sandstone were unsaturated. Their current saturation is
believed to be a result of mine water discharges and perco-
lation from tailings slurry water.
The alluvium and Tres Hermanos Sandstone are not currently
used as a water supply source. The Westwater Canyon Sand-
stone is presently a major water supply formation. Contami-
nated water in the Tres Hermanos-C Sandstone may eventually
flow into the Westwater Canyon Sandstone via the Ann Lee
Mine shaft or other mine shafts or vents.
Groundwater quality data were analyzed for the alluvium,
Tres Hermanos Cl and C2 Sandstone and from beneath saturated
uranium mill tailings present on the site. The alluvium
data include background, upgradient, cross-gradient, on-site
and down gradient samples. The Tres Hermanos-Cl Sandstone
data are from only down gradient samples. The Tres
Hermanos-C2 Sandstone data are from cross-gradient and down
gradient samples.
Levels for arsenic, cadmium, chromium, gross alpha, radium,
selenium, and silver exceeded the standards in some samples.
Chromium concentrations were higher in on-site and down
gradient samples in the tailings, alluvium and Tres Hermanos
Sandstones than in background or cross-gradient samples.
Twenty four out of 68 analyses for selenium exceeded the
limits for the standard; concentrations are highest in the
background and upgradient alluvium. Radium concentrations
from samples in the on-site tailings and alluvium were
substantially higher than in background, upgradient,
cross-gradient or down gradient samples. The one upgradient
sample analyzed for gross alpha exceeded the standard by
more than a factor of 15.
The contaminated water in the alluvium and Tres Hermanos
Formation is draining into mine shafts and vents, mixing
with groundwater in the Westwater Canyon Sandstone. Model-
ing indicates that contaminants are dispersed in the
Westwater Canyon Sandstone within 400 feet of the mixing
zone and that drainage and dilution of the contaminated
water will be completed in about 100 years.
4-3
-------
TABLE 4-1
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 1 of 6
Constituent
Arsenic
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
Number of
Analyses
8
4
2
2
18
12
3
12
7
Number of
Analyses Percent
Exceeding Exceeding
Standard Standard
1 12
___
—
1 5
___ — _
___
Maximum
Value
Obtained
(mg/1) I/
0.18
0.33
— -— -
Barium
1 . 0
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 1
Alluvium 2
Alluvium 1
Tres Hermanos- 1
C 2 Sandstone
Alluvium 7
Uranium Mill 10
Tailings
Alluvium 2
Tres Hermanos- 8
C 1 Sandstone
Tres Hermanos- 3
C 2 Sandstone
4-4
-------
TABLE 4-1
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 2 of 6
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Cadmium 0.01 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Chromium 0.05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
•Formation of Number of
Completion Analyses
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
7
4
1
2
16
12
3
12
7
7
4
1
2
16
12
3
12
7
Number of
Analyses
Exceeding
Standard
E
i
—
—
—
—
___
—
—
—
2
1
1
1
2
Percent
Exceeding
Standard
E
6
— _
—
___
12
8
33
8
28
Maximum
Value
Obtained
(mg/1) I/
0.10
___
— -
— — —
—
— — —
0.20
0.10
0.17
0.21
0.11
4-5
-------
TABLE 4-1
Site Name: Aabrosia Lake (Hew Mexico)
Data Evaluation: Site Water Quality Coapared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 3 of 6
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Gross Alpha 15.0 pCi/1 Background
(excluding radon Upgradient
and uranium) Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Lead 0 . 05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Formation of Ni
Completion A]
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
•C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
amber of
nalyses
1
2 2/
1
1
1 3/
1
1
1 3/
1
1
2
1
1
7
10
2
8
3
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
- _.... _HW ....
1 100 251.72
3/3/3/
3/ 3/ 3/
— — — — «« ___
— ___ ___
— _ _ —
4-6
-------
TABLE 4-1
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 4 of 6
Constituent
Mercury
Ra-226 +
Ra-228
(Radium)
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.002 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
5.0 pCi/1 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Number of Maximum
Analyses Percent Value
Formation of Number of Exceeding Exceeding Obtained
Completion Analyses Standard Standard (mg/1) I/
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
1 — — — — — — — —
2
6
9
— — — •»" "-
8
3
1
4 4/
1
2 4/
8 7 5/ 87 410
10 10 5/ 100 240
1
10 2 5/ 20 22.0
4 1 5/ 25 5.6
4-7
-------
TABLE 4-1
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 5 of 6
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Selenium 0.01 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Silver 0.05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Formation of Number of
Completion Analyses
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Herraanos-
C 2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C 2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
C 1 Sandstone
Tres Hermanos-
C 2 Sandstone
8
4
2
2
18
12
3
12
7
1
2
1
1
7
10
2
8
3
Number of
Analyses
Exceeding
Standard
2
2
2
6
7
1
4
«__
1
— r—
Percent
Exceeding
Standard
25
50
100
33
58
33
33
___
14
Maximum
Value
Obtained
(mg/1) I/
0.95
0.53
0.033
0.147
0.019
0.127
0.225
___
0.15
___
4-8
-------
TABLE 4-1
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 6 of 6
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Uranium data available for 1 of 2 samples.
3/ Uranium not analyzed.
4/ Analyses for Ra-226 only.
5/ Ra-226 values. Ra-228 values were all less than the standard.
Standard not exceeded.
4-9
-------
TABLE 4-2 Page 1 of 8
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Conpared to U.S. EPA Standards Not Included in 40 CFR 192.32{a)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Chloride 250 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Copper 1.0 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Formation of Number of
Completion Analyses
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C2 Sandstone
Alluvium
Uranium Hill
Tailings
Alluvium
Tres Hermanos-
Cl Sandstone
Tres Hermanos-
C2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C2. Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
Cl Sandstone
Tres Hermanos-
C2 Sandstone
9
4
7-
2
19
11
4
13
8
1
2
1
1
7
10
2
8
3
Number of Maximum
Analyses Percent Value
Exceeding Exceeding obtained
Standard Standard (mg/1) I/
___ — — -
— -
— - —
4 21 489
— _ — —
2 50 300
2 15 270
___ _ — —
".
___ . ___ -~
— _ — _
.
4-10
-------
TABLE 4-2
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 2 of 8
in 40 CFR 192.32(a)
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Fluoride 1.4 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Hydrogen Sulfide 0.05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Formation of Number of
Completion Analyses
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
Cl Sandstone
Tres Hermanos-
C2 Sandstone
Alluvium
Alluvium
Alluvium
Tres Hermanos-
C2 Sandstone
Alluvium
Uranium Mill
Tailings
Alluvium
Tres Hermanos-
Cl Sandstone
Tres Hermanos-
C2 Sandstone
7
4
1
2
12
11
3
12
7
1
1
1
1
1
1
1
1
1
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
... ... ...
3 75 2.2
... ... ...
_ —
2 16 15.0
10 90 21.0
1 33 2.2
6 50 2.1
... ... ...
... ... ...
... ... ...
... — _ ...
... ___ ...
... ... ...
... ... ...
... ... ...
_— _ — —
... ... ...
4-11
-------
TABLE 4-2
Site Name: Ambrosia Lake (Mew Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Pago 3 of 8
in 40 CFR 192.32(a)
"Constituent
Iron
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Manganese
0.30 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
0.05 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Alluvium 4
Alluvium 1
Tres Hermanos- 2
C2 Sandstone
Alluvium 15
Uranium Mill 11
Tailings
Alluvium 3
Tres Hermanos- 12
Cl Sandstone
Tres Hermanos- 7
C2 Sandstone
Alluvium 7
Alluvium 2
Alluvium 1
Tres Hermanos- 2
C2 Sandstone
Alluvium 15
Uranium Mill 11
Tailings
Alluvium 3
Tres Hermanos- 11
Cl Sandstone
Tres Hermanos- 7
C2 Sandstone
6
1
14
26
27
66
42
85
50
93
66
54
85
0.61
5.49
1.46
4.13
28.8
0.17
0.07
0.68
4.23
0.13
1.82
4-12
-------
TABLE 4-2
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 4 of 8
in 40 CFR 192.32(a)
Constituent
Molybdenum
Standard
(mg/1) l/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.10
Nitrate 2/
44
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down' gradient
Down gradient
Down gradient
Alluvium 8
Alluvium 4
Alluvium 2
Tres Hermanos- 2
C2 Sandstone
Alluvium 18
Uranium Mill 12
Tailings
Alluvium 3
Tres Hermanos- 12
Cl Sandstone
Tres Hermanos- 7
C2 Sandstone
Alluvium 8
Alluvium 4
Alluvium 6
Tres Hermanos- 2
C2 Sandstone
Alluvium 16
Uranium Mill ll
Tailings
Alluvium 4
Tres Hermanos- 13
Cl Sandstone
Tres Hermanos- 8
C2 Sandstone
7
3
2
2
18
12
3
12
2
1
1
5
2
7
88
75
100
100
100
100
100
100
86
25
25
6
45
50
53
0.22
1.87
0.50
0.17
225
250
3.17
10.3
0.35
49.0
55.0
150
4900
140
400
4-13
-------
TABLE 4-2
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S.
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 5 of 8
EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
PH 3/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
6.5 to 8.5 Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Sulfate
250
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 9
Alluvium 4
Alluvium 7
Tres Hermanos- 2
C2 Sandstone
Alluvium 18
Uranium Mill 11
Tailings
Alluvium 4
Tres Hermanos- 13
Cl Sandstone
Tres Hermanos- 8
C2 Sandstone
Alluvium 9
Alluvium 4
Alluvium 7
Tres Hermanos- 2
C2 Sandstone
Alluvium 19
Uranium Mill 12
Tailings
Alluvium 4
Tres Hermanos- 13
Cl Sandstone
Tres Hermanos- 8
C2 Sandstone
3
10
1
3
9
4
7
2
19
12
4
11
100
16
90
25
23
12
100
100
100
100
100
100
100
84
100
12.2
9.97
10.13
11.18
12.46
11.92
4940
2750
2440
633
10,300
11,000
4440
4010
3970
4-14
-------
TABLE 4-2
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 6 of 8
in 40 CFR 192.32(a)
Constituent
Sulfide
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05
Total Solids
500
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Alluvium l
Alluvium l
Alluvium l
Tres Hermanos- 1
C2 Sandstone
Alluvium 6
Uranium Mill 9
Tailings
Alluvium 2
Tres Hermanos- 7
Cl Sandstone
Tres Hermanos- 3
C2 Sandstone
Alluvium 8
Alluvium 4
Alluvium 2
Tres Hermanos- 2
C2 Sandstone
Alluvium 17
Uranium Mill 10
Tailings
Alluvium 3
Tres Hermanos- 12
Cl Sandstone
Tres Hermanos- 7
C2 Sandstone
1
1
6
9
2
7
8
4
2
2
17
10
3
12
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
0.10
0.10
0.10
0.10
0.10
0.10
0.10
8080
4400
4060
1880
20,900
25,800
7250
7190
6490
4-15
-------
TABLE 4-2 Pa9e 7 of 8
Site Kama: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Constituent
Uranium 4/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.044
Zinc
5.0
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Background
Upgradient
Cross-gradient
Cross-gradient
On-Site
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 8
Alluvium 3
Alluvium 2
Tres Hermanos- 2
C2 Sandstone
Alluvium 17
Uranium Mill 10
Tailings
Alluvium 3
Tres Hermanos- 11
Cl Sandstone
Tres Hermanos- 7
C2 Sandstone
Alluvium 1
Alluvium 1
Alluvium 1
Tres Hermanos- 1
C2 Sandstone
Alluvium 6
Uranium Mill 9
Tailings
Alluvium 2
Tres Hermanos- 7
Cl Sandstone
Tres Hermanos- 3
C2 Sandstone
17
10
2
8
37
100
100
100
100
66
72
29
1.26
3.31
5.34
14.70
10.70
2.80
11.80
1.25
4-16
-------
TABLE 4-2 page 8 of 8
Site Name: Ambrosia Lake (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pci/l of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
Standard not exceeded.
4-17
-------
4.3 CANONSBURG, PENNSYLVANIA - SUMMARY OF WATER QUALITY
The collection of hydrogeological and groundwater quality
data for the Canonsburg site began in 1979. However, due to
the potential for high levels of radioactive contamination,
the location of wells was restricted. Also, aquifer pump
tests were prohibited due to the potential for withdrawing
radioactively contaminated groundwater. In 1982, additional
drilling was conducted to further characterize the ground-
water regime. The 1982 effort concluded that significant
data gaps still existed regarding the hydrogeological
information.
From December 1982 through March 1983, a third field effort
was undertaken to characterize the site hydrogeology.
During this effort, monitoring wells were constructed
on-site in the overburden and in the bedrock. Off-site
monitoring wells were constructed south of the site.
Aquifer data from the unconsolidated material and the
bedrock were collected. Surface water data from Chartiers
Creek were collected to determine the hydrological relation-
ship between the groundwater and Chartiers Creek.
The amount of groundwater quality data for the period 1979
to March 1983 is minimal. The value of these data may be
limited with regards to site groundwater quality character-
ization. This is primarily due to the early drilling
restrictions which applied to most of the site. The data
that are available for this period of time show that several
constituents in the groundwater beneath the site, and in the
vicinity of the site, exceeded existing standards. Some
on-site groundwater samples exceeded existing standards for
arsenic, chloride, iron, pH, selenium and sulfate. Nitrate,
pH and selenium exceeded the existing standards in some
off-site groundwater samples.
Remedial action at the process site is complete. The data
evaluated and presented in the following tables represent
post-closure groundwater quality data. These data are from
two quarterly post-remedial sampling efforts conducted
between 08/05/86 and 11/06/86. Presently, seven wells (four
on-site and three off-site) comprise the primary monitoring
network.
Two saturated zones are presently monitored. These are the
unconsolidated soils and shallow shale and limestone.
Recharge is from the east and discharge occurs to Chartiers
Creek to the north, west, and south. Some groundwater may
flow beneath Chartiers Creek in the shallow shale/limestone.
Approximately 12 wells have been identified within a one-
mile radius on the site. Most of these wells have been
abandoned , with the remaining wells receiving limited use,
primarily for watering gardens.
4-18
-------
Monitoring data from the site include upgradient, cross-
gradient and down gradient samples. Background data are not
available. Table 1 shows that none of the constituents
exceeded standards. However, this must be evaluated in
terms of the data time interval (six months) and that the
data are from post-closure monitoring.
Most of the groundwater from the contaminated alluvium
discharges to Chartier Creek within a few hundred feet of
the site; some may underflow the creek in shallow bedrock.
Modeling indicates that discharges of the mobile contami-
nants (NO3, Clf SO4, TDS) will be within standards within 60
years and discharges of the attenuated contaminants (U, Mo,
metals) in excess of standards will continue for two to
three times as long.
4-19
-------
TABLE 4-3
Site Name: Canonsburg (Pennsylvania)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards fron 40 CFR 192.32(a)
Data Interval: 08/05/86 to 11/06/86
Page 1 of 2
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha
(excluding radon
and uranium)
Standard
(mg/1) I/
0.05
1.0
0.01
0.05
15.0 pCi/1
Hydraulic Flow
Relationship
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
2
8
5
2
8
5
2
8
5
2
8
1
1
1
Number of
Analyses
Exceeding
Standard
• •^
~ — «••
«••""
• HM
___
Percent
Exceeding
Standard
««•»
_»
M««
__.
__«
Maximum
Value
Obtained
(mg/1) I/
__~
:::
—
—
4-20
-------
TABLE 4-3
Site Name: Canonsburg (Pennsylvania)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 08/05/86 to 11/06/86
Page 2 of 2
Constituent
Lead
Mercury
Ra-226 + Ra-228
(Radium)
Selenium
Silver
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Upgradient
Cross-gradient
On-Site
0.002 Upgradient
Cross-gradient
On-Site
5.0 pCi/1 Upgradient
Cross-gradient
On-Site
0 . 01 Upgradient
Cross-gradient
On-Site
0.05 Upgradient
Cross-gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
2
8
5
2
8
4
2
8
5
2
8
5
2
8
Number of
Analyses
Exceeding
Standard
___
Maximum
Percent Value
Exceeding Obtained
Standard (mg/1) I/
— — — — — —
••»__ • III •!
— — — — — —
I/ Values are reported in mg/1 unless otherwise indicated.
Standard not exceeded.
4-21
-------
TABLE 4-4 Page 1 of 4
Sit© Kama: Canonaburg (Pennsylvania)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/05/86 to 11/06/86
Constituent
Chloride
Copper
Fluoride
Hydrogen Sulfide
Standard
(mg/1) I/
250
1.0
1.4
0.05
Hydraulic Flow
Relationship
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
2
8
5
2
8
5
2
8
1
1
1
Number of
Analyses
Exceeding
Standard
••_—
••««
— — —
—
Percent
Exceeding
Standard
•••»«•
—
— -
Maximum
Value
Obtained
(mg/1) I/
••••
«•_
«H
— " —
4-22 i
-------
TABLE 4-4
Site Name: Canonsburg (Pennsylvania)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 08/05/86 to 11/06/86
Page 2 of 4
in 40 CFR 192.32(a)
Constituent
Iron
Manganese
Molybdenum
Nitrate 2/
Standard
(mg/1) I/
0.30
0.05
0.10
44
Hydraulic Flow
Relationship
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
2
8
5
2
8
5
2
8
5
2
8
Number of
Analyses
Exceeding
Standard
4
2
2
5
2
8
5
2
8
Percent
Exceeding
Standard
80
100
25
100
100
100
100
100
100
—
Maximum
Value
Obtained
(mg/1) I/
14.5
1.42
14.7
3.32
11.5
9.41
0.27
0.18
0.20
___
4-23
-------
I
TABLE 4-4
Site Name: Canonsburg (Pennsylvania)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192. 32 (a)
plus Uranium and Molybdenum
Data Interval: 08/05/86 to 11/06/86
3 Of 4
Constituent
PH 3/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Sulfate
Sulfide
Total Solids
6.5 to 8.5
250
0.05
500
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
5
2
8
5
2
8
4
2
8
•5
2
8
3
6
60
75
100
100
100
100
40
100
5.60
6.34
626
0.10
0.10
0.10
802
1310
4-24
-------
TABLE 4-4
Site Name: Canonsburg (Pennsylvania)
Data Evaluation: Site Water Quality compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data interval: 08/05/86 to 11/06/86
Page 4 of 4
in 40 CFR 192.32(a)
Constituent
Uranium 4/
Zinc
Standard
(mg/1) I/
0.044
5.0
Hydraulic Flow
Relationship
Upgradient
Cross-gradient
On-Site
Upgradient
Cross-gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
2
8
5
2
8
Number of
Analyses
Exceeding
Standard
2
2
Percent
Exceeding
Standard
100
25
•
Maximum
Value
Obtained
(mg/1) I/
0.0221
0.0492
___
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
— Standard not exceeded.
4-25
-------
4.4 DURANGO, COLORADO - SUMMARY OF WATER QUALITY
The analysis of groundwater quality at the Durango site
involved upgradient and down gradient data. No background
or preprocessing era data were available. There are no
current groundwater users within two miles down gradient of
the site.
Levels of arsenic, chromium and selenium exceeded the
standards in some samples. Selenium exceeded the standard
in one upgradient sample by a factor of 35 and in nearly 80
percent of the down gradient samples by factors as high as
190. Arsenic and chromium exceeded the standards only in
the down gradient samples, arsenic by a factor of 16 and
chromium by a factor of two.
The contaminated groundwater discharges, to the Animas River
within 100 to 500 feet of the piles and ponds. Modeling
indicates that the mobile contaminants will be flushed from
the alluvial aquifer in approximately 5 years and from the
Menefee Formation in 40 years. Flushing of the attenuated
contaminants from the alluvial aquifer will take 15 years
and from the Menefee Formation about 40 years.
4-26
-------
TABLE 4-5
Site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/01/82 to 11/13/85
Page 1 of 5
Constituent
Arsenic
standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05
Barium
1 . 0
Upgradient
Down gradient
Down gradient
Down gradient
Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy 5
gravel, poorly
graded
Gravel or sandy 21
gravel, poorly
graded
Silty Sand or 6
Silty gravelly
sand
Shale 22
Gravel or sandy 1
gravel, poorly
graded
Gravel or sandy 5
gravel, poorly
graded
Silty Sand or 1
Silty gravelly
sand
Shale 5
28
16
0.83
0.10
4-27
-------
TABLE 4-5
Site Name: Durango (Colorado)
Data Evaluation: site Water Quality Coapared to U.S. EPA Standards fron 40 CFR 192.32(a)
Data Interval: 09/01/82 to 11/13/85
Page 2 of 5
Constituent
Cadmium
Standard Hydraulic Flow
(ng/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Chromium
0.01 Upgradient
Down gradient
Down gradient
Down gradient
0.05 Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
4
21
6
20
16
0.10
4-28
-------
TABLE 4-5
Site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/01/82 to 11/13/85
Page 3 of 5
Constituent
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
standard
Percent
Exceeding
standard
Maximum
Value
Obtained
(mg/1) I/
Gross Alpha 15.0 pCi/1 Upgradient
(excluding radon
and uranium)
Down gradient
Down gradient
Lead
Down gradient
0.05 Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
4
21
20
4-29
-------
TABLE 4-5
site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/01/82 to 11/13/85
Page 4 of 5
Constituent
Mercury
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Ra-226 + Ra-228
(Radium)
0.002 Upgradient
Down gradient
Down gradient
Down gradient
5.0 pCi/1 Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy 1
gravel, poorly
graded
Gravel or sandy 1
gravel, poorly
graded
silty Sand or 1
Silty gravelly
sand
.Shale l
Gravel or sandy 2 2/
gravel, poorly
graded
Gravel or sandy 12 2/
gravel, poorly
graded
Silty Sand or 2 2/
Silty gravelly
sand
Shale 10 2/
4-30
-------
TABLE 4-5
Site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/01/82 to 11/13/85
Page 5 of 5
Constituent
Selenium
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Silver
0.01 Upgradient
Down gradient
Down gradient
Down gradient
0.05 Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty Sand or
Silty gravelly
sand
Shale
21
22
17
18
20
80
66
81
0.36
1.20
1.90
1.60
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Analyses for Ra-226 only.
— Standard not exceeded.
4-31
-------
TABLE 4-6
Site Narset Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 09/01/82 to 11/13/85
Page 1 of 8
Constituent
Chloride
standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of-
Analyses
Number of
Analyses',
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
250
Copper
1.0
Upgradient
Down gradient
Down gradient
Down gradient
Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy 5
gravel, poorly
graded
Gravel or sandy 21
gravel, poorly
graded
Silty sand or 6
silty gravelly
sand
Shale 22
Gravel or sandy 4
gravel, poorly
graded
Gravel or sandy 21
gravel, poorly
graded
Silty sand or 6
silty gravelly
sand
Shale 20
12
42
66
54
1100
390
1100
4-32
-------
TABLE 4-6
Site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 09/01/82 to 11/13/85
Page 2 of 8
Constituent
Fluoride
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Hydrogen Sulfide
1.4 Upgradient
Down gradient
Down gradient
Down gradient
0.05 Upgradient
Down gradient
Down gradient
Down gradient
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty sand or
silty gravelly
sand
Shale
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Silty sand or
silty gravelly
sand
Shale
4-33
-------
TABLE 4-6
Data SatiSriit?WaSf Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 09/01/82 to 11/13/85
Page 7 of 8
Constituent
Uranium 4/
Standard
(mg/1) I/
0.044
Zinc
5.0
Hydraulic Flow
Relationship
Upgradient
Down gradient
Down gradient
Down gradient
Upgradient
Down gradient
Down gradient
Down gradient
Formation of
Completiqn
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Gravel or sandy 5
gravel, poorly
graded
Gravel or sandy 21
gravel, poorly
graded
Silty sand or 6
silty gravelly
sand
Shale 22
Gravel of sandy 4
gravel, poorly
graded
Gravel or sandy 21
gravel, poorly
graded
Silty sand or 6
silty gravelly
sand
Shale 20
Percent
Exceeding
Standard
20
18
6
22
86
100
100
Maximum
Value
Obtained
0.15
6.20
2.40
4.07
4-38
-------
TABLE 4-6
Site Name: Durango (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/01/82 to 11/13/85
Page 8 of 8
in 40 CFR 192.32(a)
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
Standard not exceeded.
4-39
-------
4.5 GRAND JUNCTION, COLORADO - SUMMARY OF WATER QUALITY
The Grand Junction process site lies in an industrial area
along the northern bank of the Colorado River. Sedimentary
units in and around the site are, in ascending order, the
Dakota Sandstone, the Mancos Shale, and alluvium. Two
drillings programs were conducted; the first phase was to
determine the source of contamination to the alluvium; the
second considered background and down gradient hydraulics
and water quality in the alluvium and underlying beds of the
Mancos Shale and Dakota Sandstone.
Groundwater sampling indicated that limits of concentrations
for arsenic, cadmium, radium, chromium, selenium, and gross
alpha were exceeded. Arsenic and cadmium concentrations
were higher in on-site (alluvium and tailings) samples than
in other localities sampled in the alluvium. One of 23
upgradient analyses for chromium and twelve out of 33
on-site analysis for selenium exceeded the limit for the
standard. Four of 9 down gradient samples exceeded the
standard for gross alpha. Eight of 18 on-site analyses for
radium as well as three of 30 down gradient radium samples,
exceeded the limit for the standard.
Groundwater flow discharges in the Colorado River with some
possibly contributing to recharge of the Dakota Sandstone at
a subcrop 1/2 mile west of the site. Based on modeling
results, discharge and dispersal of the mobile contaminants
is expected within 50 to 60 years; uranium and ammonia may
persist in the alluvial aquifers for 150 to 300 years.
4-40
-------
TABLE 4-7
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/23/77 to 09/11/85
Page 1 of 4
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Arsenic 0 . 05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Barium 1 . 0 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Cadmium 0.01 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of 1
Completion 1
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
dumber of
Analyses
6
23
9
32
1
39
6
23
9
30
1
39
6
22
9
24
1
31
Number of
Analyses
Exceeding
Standard
- ___
5
1
1
___
___
— _
___
__..»
w__
___
___
6
1
___
Percent
Exceeding
Standard
___
15
100
2
HIWW
___
___
___
»»»
_
___
___
25
100
Maximum
Value
Obtained
(mg/1) I/
__ _
0.18
1.68
0.11
___
___
—
___
___
___
___
— — —
0.42
0.035
4-41
-------
TABU; 4-7
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 09/23/77 to 09/11/85
Page 2 of 4
EPA Standards from 40 CFR 192.32(a)
Constituent
Chromium
Gross Alpha
(excluding radon
and uranium)
Lead
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
15.0 pCi/1 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
0 . 05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of 1
Completion 1
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
All-uvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses Percent
lumber of Exceeding Exceeding
Analyses Standard Standard
6
23 14
9
31
1
39
2 2/ 2/ 2/
4 2/ 2/ 2/
3 2/ 2/ 2/
4 3/ 3 100
1
9 4/ 4 100
4
13
6
16
1
22
Maximum
Value
Obtained
(mg/1) I/
0.07
— —
— — — .
—
™""* —
2/
2/
2/
129.20
— — ""
187.40
_•••
««—
— — —
—
— — —
4-42
-------
TABLE 4-7
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/23/77 to 09/11/85
Page 3 of 4
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Mercury 0.002 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Ra-226 + Ra-228 5.0 pCi/1 Background
(Radium) Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Selenium 0.01 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of I
Completion i
Alluvium '
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses
6
22
9
24
1
31
5
18
7
18 5/
1
30 5/
6
23
9
32
1
39
Number of
Analyses
Exceeding
Standard
8 6/
-~
3 6/
1
"
11
1
1
Percent
Exceeding
Standard
_ —
44
___
10
16
___
34
100
2
Maximum
Value
Obtained
(mg/1) I/
___
29.0
___
18.0
0.014
___
___
0.24
1.69
0.012
4-43
-------
TABLE 4-7
Site Name; Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 09/23/77 to 09/11/85
Page 4 of *
Constituent
Silver
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Alluvium 4
Alluvium 13
Alluvium 6
Alluvium 16
Uranium Mill 1
Tailings
Alluvium 22
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Uranium not analyzed.
3/ Uranium not analyzed for one sample.
4/ Uranium analyzed in 4 of 9 samples.
5/ Ra-226 only.
6/ Values for Ra-226 only. Ra-228 values were all less than the standard.
Standard not exceeded.
4-44
-------
TABLE 4-8
Site Name: Grand Junction (Colorado)
Data Evaluation: site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/23/77 to 09/11/85
Page 1 of 5
in 40 CFR 192.32(a)
Constituent
Chloride
Copper
Fluoride
Standard Hydraulic Flow
(mg/1) I/ Relationship
250 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
1 . 0 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
1 . 4 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses
52
23
9
32
1
40
6
23
9
32
1
39
6
22
9
24
1
31
Number of
Analyses
Exceeding
Standard
39
15
9
32
1
40
••••_
___
___
___
___
2
20
1
- .. 8
Percent
Exceeding
Standard
75
65
100
100
100
.100
_.
___
— «»
«__
— — —
9
83
100
25
Maximum
Value
Obtained
(mg/1) I/
473
783
1250
1030
2990
1270
___
»*>«.
___
»_
1.60
4.90
16.0
3.70
4-45
-------
TABLE 4-8
Site Kama: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/23/77 to 09/11/85
Page 2 of 5
in 40 CFR 192.32(a)
Constituent
Hydrogen Sulfide
Iron
Manganese
Standard Hydraulic Flow
(mg/1) I/ Relationship
0 . 05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
0.30 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
0.05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses
4
13
6
12
1
18
6
23
9
32
1
39
6
23
9
32
1
39
Number of
Analyses
Exceeding
Standard
4
13
6
12
— -»~
18
4
10
8
22
__ —
26
6
23
9
32
1
39
Percent
Exceeding
Standard
100
100
100
100
100
66
43
88
68
™"~™
66
100
100
100
10
100
100
Maximum
Value
Obtained
(mg/1) I/
1.20
0.20
0.36
0.20
0*> f\
.20
1.20
3.04
5.70
12.00
16.00
8.74
2.91
4.60
10.00
0.33
1 O A
334
4-46
-------
TABLE 4-8
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/23/77 to 09/11/85
Page 3 of 5
in 40 CFR 192.32(a)
Constituent
Molybdenum
Nitrate 2/
PH 3/
Standard Hydraulic Flow
(mg/1) I/ Relationship
0 . 10 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
44 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
6.5 to 8.5. Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses
6
23
9
32
1
39
8
23
9
28
1
35
52
23
9
32
1
39
Number of
Analyses
Exceeding
Standard
|_1 n la
6
5
24
1
17
— — »
___
1
1
«_»•
___
___
___
___
Percent
Exceeding
standard
26
56
75
100
44
___
»_«
3
100
••«_
««•»
«.__
_•»-•
___
Maximum
Value
Obtained
(mg/1) I/
0.15
0.14
0.53
8.65
0.47
•••••
___
50.0
1100
•»•»»
— _••
«>H»M
IT- annul
*.*...
4-47
-------
TABLE 4-8
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/23/77 to 09/11/85
Page 4 of 5
,0/»\
in 40 CFR 192. 32 (a)
Constituent
Sulfate
Sulfide
Total Solids
Standard Hydraulic Flow
(mg/1) I/ Relationship
250 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
0.05 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
500 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Uranium Mill
Tailings
Alluvium
Number of
Analyses
52
23
9
32
1
39
2
9
3
8
1
52
23
9
32
1
39
Number of
Analyses
Exceeding
Standard
52
20
9
32
1
39
2
9
3
8
—
52
22
9
32
- —
39
Percent
Exceeding
Standard
100
86
100
100
100
100
100
100
100
100
— —
100
95
100
100
— —
100
Maximum
Value
Obtained
(mg/1) I/
4170
3410
4000
4900
6110
4500
0.10
0.10
0.10
0.10
"~ — •"
7220
6930
8530
8100
• »
12,134
4-48
-------
TABLE 4-8
Site Name: Grand Junction (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 09/23/77 to 09/11/85
Page 5 of 5
in 40 CFR 192.32(a)
Constituent
Uranium 4/
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Zinc
0.044 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
5.0 Background
Upgradient
Cross-gradient
On-Site
On-Site
Down gradient
Alluvium i
Alluvium i
Alluvium i
Alluvium 3
Uranium Mill i
Tailings
Alluvium 4
Alluvium 6
Alluvium 23
Alluvium 9
Alluvium 32
Uranium Mill i
Tailings
Alluvium 39
100
100
0.185
0.445
i/
2/
I/
Standard not exceeded.
Values are reported in mg/1 unless otherwise indicated.
SD^TS^i0"8/?* nŁfate aS nitr°9en at a leYel of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
pH reported in Standard units.
equivalent °f °<044 mg/1' ass™^<3 the bulk of uranium is U-238. All analyses are reported as
4-49
-------
4.6 GUNNISON, COLORADO - SUMMARY OF WATER QUALITY
The site is immediately south of the City of Gunnison,
Colorado; and is between the Gunnison River and Tomichi
Seek The site overlies the principal.aquifer of the rea.
SSrl than75 wells, most of them domestic wells less than 30
feet deep, are within one mile of the site. The city 01
Gunnison operates a municipal well field approximately one
mile north (upgradient) of the site.
The quality of background water is generally potable with
some exceptions. High concentrations of iron are found in
tte allSvial aquifer? Hydrogen sulfide is found in a
reducing zone along the Gunnison River.
The groundwater analyses for the Gunnison si^ included
background, upgradient, cross-gradient, on-site jnd down
or-adisnt data. All data are from wells in the alluvium.
Ia?iiS was the only constituent which exceeded the stan-
dSSTinthe background samples. One of 21 background
samples exceeded the barium standard. No constituents
exceeded the standards in the upgradient or cross-gradient
wells.
Arsenic and gross alpha exceeded the standards in the
on-site samples. The arsenic standard was exceeded in 3 out
of 7 sampSI, with a maximum value exceeding the standard by
* -Factor of more than four. One gross alpha sample was
rallied and"it eSeeded the standard by a factor of more
than ten.
The down gradient samples contained the greatest number of
contaminants. In these samples the ^andardj. were egeectod
fn-r arsenic cadmium, gross alpha, mercury and selenium.
TwŁ oufo-f^rsamplesexceeded the arsenic standard by a
factor of less than two. The maximum values for both
cadmium and gross alpha exceeded standards by more than a
factor of three. The one mercury sample analyzed exceeded
the standard by a factor of 14,300. Nine out of 123 samples
analvzSdfor selenium exceeded the standard. The maximum
5SSS for selenium was more than a factor of 10 greater than
the standard.
The contaminants disperse in the alluvial aquifer which
discharges at the confluence of the Gunnison River and
Tomichi Creek, 2 miles from the site. . Modeling indicates
that discharges of the mobile contaminants will reach
background standards in approximately 75 years. The dis-
charge period of the attenuated contaminants was not
modeled.
4-50
-------
TABLE 4-9
Site Name: Gunnison (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 10/12/83 to 06/20/85
Page 1 of 3
Constituent
Arsenic
Barium
Cadmium
Chromium
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Upgradient
Cross-gradient
On-Site
Down gradient
1 . 0 Background
Upgradient
Cross-gradient
On-Site
Down gradient
0.01 Background
Upgradient
Cross-grad ient
On-Site
Down gradient
0 . 05 Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
21
5
2
7
123
21
5
2
7
123
21
5
2 '
7
123
21
5
2
7
122
Number of
Analyses
Exceeding
Standard
___
3
2
1
_ —
___
7
H-.W
~~
Percent
Exceeding
Standard
___
___
42
2
5
___
___
___
— _
6
__«
___
_ —
Maximum
Value
Obtained
(mg/1) I/
___
0.23
0.07
1.2
___
___
M__
___
___
0.034
- «._•_
___
___
4-51
-------
TABLE 4-9
Site Name: Gunnison (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 10/12/83 to 06/20/85
Page 2 of 3
Constituent
Gross Alpha
(excluding radon
and uranium)
Lead
,
Mercury
Ra-226 + Ra-228
(Radium)
Standard Hydraulic Flow
(mg/1) I/ Relationship
15.0 pCi/1 Background
Upgradient
Cross-gradient
On-Site
Down gradient
0.05 Background
Upgradient
Cross-gradient
On-Site
Down gradient
0.002 Background
Upgradient
Cross-gradient
On-Site
Down gradient
5.0 pCi/1 Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
5
1
1
1
11
21 '
5
2
7
121
1
1
1
1
1
6 y
2
1
4 2/
23
Number of
Analyses
Exceeding
Standard
_ —
— —
— — —
1
4
— —
_ —
— — —
___
1
• — _
Percent
Exceeding
Standard
—
— — —
100
36
— — —
—
- •" ••• ~ -
— — —
— ~
100
— — —
—
—
— — —
Maximum
Value
Obtained
(ng/i) I/
••— —
— — —
151.12
49.98
— — —
— — —
-——
— —
— — —
— — —
— — —
28.6
— — —
— — —
— — —
— — —
4-52
-------
TABLE 4-9
Site Name: Gunnison (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 10/12/83 to 06/20/85
Page 3 of 3
Constituent
Selenium
Silver
Standard
(mg/1) I/
0.01
0.05
I/ Values are reported in
2/ Analyses
Standard
Hydraulic Flow
Relationship
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
21
5
2
7
123
1
1
1
1
1
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
»«.« •»— — «••.•«.
___ _ — - —
___ , — _
___ ___ ___
9 7 0.103
___ ___ •_-•••
___ __— ___
___ — -
___ ___ ___
— — — — — — ___
mg/1 unless otherwise indicated.
for Ra-226 only.
not exceeded.
4-53
-------
TABLE 4-10
Site Haae: Gunnison (Colorado)
Data Evaluation: Site Water Quality Coapared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 10/12/83 to 06/20/85
Page 1 of 4
in 40 CER 192.32(3)
Standard
Constituent (mg/1) I/
Chloride 250
Copper 1.0.
Fluoride 1.4
Hydrogen Sulfide 0.05
Iron 0.30
Hydraulic Flow
Relationship
Background
Upgradient. .
Cross-gradient
On-Site
Down gradient
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
21
5
2
7
123
15
3
1
5
81
15
2
1
4
64
1
1
1
1
1
21
5
2
7
122
Number of
Analyses
Exceeding
Standard
^«^
___
- - __-
4
— —
10
2
7
69
Percent
Exceeding
Standard
—
— — - -
6
™
47
100
100
56
Maximum
Value
Obtained
(mg/1) I/
***•••»
- . ~~~ - -
2.60
— — —
5.63
1.90
37.80
101
4-54
-------
TABLE 4-10
Site Name: Gunnison (Colorado)
Data Evaluation: Site Vfater Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 10/12/83 to 06/20/85
Page 2 of 4
in 40 CFR 192.32(a)
Constituent
Manganese
Molybdenum
Nitrate 2/
pH 3/
Sulfate
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Upgradient
Cross-gradient
On-Site
Down gradient
0 . 10 Background
Upgradient
Cross-gradient
On-Site
Down gradient
44 Background
Upgradient
Cross-gradient
On-Site
Down gradient
6.5 to 8.5 Background
Upgradient
Cross-gradient
On-Site
Down gradient
250 Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
15
5
2
6
101
21
5
2
7
123
21
5
2
7
123
21
5
2
7
117
21
5
2
7
122
Number of
Analyses
Exceeding
Standard
11
2
2
6
85
___
.
2
___
,
6
___
1
7
66
_._
- —
- —
7
62
Percent
Exceeding
Standard
73
40
100
100
84
___
— _
_ —
29
__..
—
4
___
— -
50
100
56
...
___
___
100
50
Maximum
Value
Obtained
(mg/1) I/
4.69
0.29
2.09
34.30
77.00
___
_ —
0.18
— -
___
- — _
_ —
___
110
___
___
6.08
5.66
5.08/12.32
...
___
___
1480
1820
4-55
-------
TABLE 4-10
Site Name: Gunnison (Colorado)
Data Evaluation: Site Hater Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data interval: 10/12/83 to 06/20/85
Page 3 of 4
in 40 CFR 192.32(a)
Constituent
Sulfide
Total Solids
Uranium 4/
Zinc
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Upgradient
Cross-gradient
On-Site
Down gradient
500 Background
Upgradient
Cross-gradient
On-Site
Down gradient
0.044 Background
Upgradient
Cross-gradient
On-Site
Down gradient
5 . 0 Background
Upgradient
Cross-gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
6
2
1
2
43
21
5
2
7
122
15
2
1
5
78
15
3
1
5
82
Number of
Analyses
Exceeding
Standard
6
2
1
2
43
1
7
78
___
2
29
___
___
Percent
Exceeding
Standard
100
100
100
100
100
4
___
100 .
63
- —
40
37
Maximum
Value
Obtained
(mg/1) I/
0.10
0.10
0.10
0.10
1.00
713
— — —
—
2510
3160
— —
0.1160
1.20
— -
—
___
4-56
-------
TABLE 4-10
Site Name: Gunnison (Colorado)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 10/12/83 to 06/20/85
Page 4 of 4
in 40 CFR 192.32(a)
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
Standard not exceeded.
4-57
-------
TABIŁ 4-11
Site Name: Lakaviaw (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 08/17/82 to 10/02/86
Page 2 of 5
Standard Hydraulic Flow
Constituent (mg/1) U Relationship
Cadmium o.Ol Background •
Cross-gradient
On-Site
Down gradient
Chromium 0.05 Background
Cross-gradient
On-Site
Down gradient
Number of
Analyses Percent
Formation of Number of Exceeding Exceeding
Completion Analyses Standard Standard
Sand or gravelly 25
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 18 15
sand, poorly
graded
Sand or gravelly 55 3 5
sand, poorly
graded
Sand or gravelly 12
sand, poorly
graded
Sand or gravelly 6
sand, poorly
graded
Sand or gravelly 15
sand, poorly
graded
Sand or gravelly 46 3 6
sand, poorly
graded
Maximum
Value
Obtained
(mg/1) I/
—
0.04
0.31
___
0.08
4-60
-------
TABLE 4-11
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 08/17/82 to 10/02/86
Page 3 of 5
Constituent
Gross Alpha
(excluding radon
and uranium)
Lead
Standard Hydraulic Flow
(mg/1) I/ Relationship
15.0 pCi/1 Background
Cross-gradient
On-Site
Down gradient
0.05 Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 9
sand, poorly
graded
Sand or gravelly 4
sand, poorly
graded
Sand or gravelly 14
sand, poorly
graded
Sand or gravelly 35
sand, poorly
graded
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
___ ___ ___
— — — — — — — —
1 100 23.32
— — -
__- — -
— — — — — — — — —
4-61
-------
TABLE 4-11
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 08/17/82 to. 10/02/86
Page 4 of 5
Constituent
Mercury
Ra-226 +
Ra-228 (Radium)
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.002 Background
Cross-gradient
On-Site
Down gradient
5.0 pCi/1 Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly 6
sand, poorly
graded
Sand or gravelly 2
sand, poorly
graded
Sand or gravelly 8
sand, poorly
graded
Sand or gravelly 20
sand, poorly
graded
Sand or gravelly 8
sand, poorly
graded
Sand or gravelly 4
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 30
sand, poorly
graded
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
— — — ___ ___
___
_. — .. . . . . .
1 3 76.0
4-62
-------
TABLE 4-11
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 08/17/82 to 10/02/86
Page 5 of 5
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Selenium 0.01 Background
Cross-gradient
On-Site
Down gradient
Silver 0.05 Background
Cross-gradient
On-Site
Down gradient
Number of Maximum
Analyses Percent Value
Formation of Number of Exceeding Exceeding Obtained
Completion Analyses Standard Standard (mg/1) I/
Sand or gravelly 10 —
sand, poorly
graded
Sand or gravelly 4 ~~~
sand, poorly
graded
Sand or gravelly 16 3 18 0.243
sand, poorly
graded
Sand or gravelly 38
sand, poorly
graded
Sand or gravelly 5
sand, poorly
graded
Sand or gravelly 2 - —
sand, poorly
graded
Sand or gravelly 7 ™
sand, poorly
graded
Sand or gravelly 19
sand, poorly
graded
I/ Values are reported in mg/1 unless otherwise indicated.
Standard not exceeded.
4-63
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 1 of 8
Standard Hydraulic Flow
Constituent (ng/1) I/ Relationship
Chloride 250 Background
Cross-gradient
On-Site
Down gradient
Copper i.o Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
25
7
18
57
10
4
15
36
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
«« «_« «.««
___ ___ ___
6 33 3400
23 40 2400
— — — »_ »»«
— ___
— - _ — ___
— -_- ___
4-64
-------
TABLE 4-12
Site Kama: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 2 of 8
Constituent
Fluoride
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
1.4
Hydrogen Sulfide
0.05
Background
Cross-gradient
On-Site
Down gradient
Background
Cross-gradient
On-Site
Down gradient
Sand or gravelly 25
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 18
sand, poorly
graded
Sand or gravelly 57
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
Sand or gravelly 1
sand, poorly
graded
10
40
4.7
45
44
78
6.27
8.8
4-65
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Conpared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 3 of 8
Constituent
Iron
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Manganese
0.30 Background
Cross-gradient
On-Site
Down gradient
0.05 Background
Cross-gradient
On-Site
Down gradient
Sand or gravelly 25
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 19
sand, poorly
graded
Sand or gravelly 57
sand, poorly
graded
Sand or gravelly 24
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 17
sand, poorly
graded
Sand or gravelly 54
sand, poorly
graded
12
12
49
31
21
37
100
70
90
27.0
9.14
0.26
8.30
25.0
24.7
4-66
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 4 of 8
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Molybdenum 0.10 Background
Cross-gradient
On-Site
Down gradient
Nitrate 2/ 44 Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly 6
sand, poorly
graded
Sand or gravelly 2
sand, poorly
graded
Sand or gravelly 9
sand, poorly
graded
Sand or gravelly 27
sand, poorly
graded
Sand or gravelly 25
sand, poorly
graded
Sand or gravelly 7
sand, poorly
graded
Sand or gravelly 18
sand, poorly
graded
Sand or gravelly 57
sand, poorly
graded
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
1 16 0.11
1 11 0.32
3 11 0.44
— — — ___ ___
— _
4-67
-------
TABLE 4-12
Site Name; LaXeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 5 of 8
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
pH 3/ 6.5 to 8.5 Background
Cross-gradient
On-Site
Down gradient
Sulfate 250 Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
25
7
18
60
25
7
18
57
Number of
Analyses
Exceeding
Standard
4
3
9
4
8
35
Percent
Exceeding
Standard
16
— — —
16
15
57
44
61
Maximum
Value
Obtained
(mg/1) I/
6.02/8.90
——
5.70
5.58/9.30
650
7300
4700
4-68
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 6 of 8
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Sulfide o.05 Background
Cross-gradient
On-Site
Down gradient
Total Solids 500 Background
Cross-gradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
1
1
1
1
25
7
18
57
Number of
Analyses
Exceeding
Standard
«_ -.
___
11
4
10
51
Maximum
Percent Value
Exceeding Obtained
Standard (mg/i) I/
— ™— «••••
— — _
___ ___
___ _ —
43 992
57 1232
55 13,836
89 12,006
4-69
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 7 of 8
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Uranium 4/ 0.044 Background
.
Cross-gradient
On-Site
Down gradient
Zinc 5.0 Background
Cross-gradient
On-Site
Down gradient
Number of Maximum
Analyses Percent Value
Formation of Number of Exceeding Exceeding Obtained
Completion Analyses Standard Standard (mg/1) I/
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
Sand or gravelly
sand, poorly
graded
7
4
9 1 11 0.10
30 — - ~"
11
6
14
46
4-70
-------
TABLE 4-12
Site Name: Lakeview (Oregon)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 08/17/82 to 10/02/86
Page 8 of 8
in 40 CFR 192.32(a)
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
Standard not exceeded.
4-71
-------
4.8 MEXICAN HAT, UTAH - SUMMARY OF WATER QUALITY
The Mexican Hat tailings site is in southeast Utah, approxi-
mately one mile south of Mexican Hat, Utah and the San Juan
River. Sampling of monitor wells indicate that the tailings
have contaminated approximately 80 million gallons of
groundwater. Seepage of contaminants into Gypsum Wash (the
major surface drainage area of the site) and subsequent
contamination of the San Juan River are of major concern.
Background water quality is unsuitable for most uses;
currently there are no groundwater withdrawals within the
site.
Of the standards contained in or referenced in 40 CFR
192.32(a), the limits for chromium, gross alpha, mercury,
radium and selenium were exceeded for some samples. Chromi-
um concentrations were higher in background samples in the
Rico Formation than in down gradient samples. Two out of 15
background analyses for radium and one out of 15 background
analyses for selenium exceeded the limit for the standard.
Two out of 14 background samples exceeded the standard for
gross alpha. One out of 2 down gradient analyses for
mercury exceeded the limit for the standard.
The contaminated groundwater appears to occur in perched
zones beneath and adjacent to the site. Because of the low
rate of movement of the perched water, over 500 years will
be required to flush the mobile contaminants from the
groundwater.
4-72
-------
TABLE 4-13
Site Name: Mexican Hat (Utah)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 04/10/85 to 11/01/85
Page 1 of 2
EPA Standards from 40 CFR 192.32(a)
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha
(excluding radon
and uranium)
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
On-Site
Down gradient
Down gradient
1 . 0 Background
On-Site
Down gradient
Down gradient
0.01 Background
On-Site
Down gradient
Down gradient
0.05 Background
On-Site
Down gradient
Down gradient
15.0 pCi/1 Background
On-Site
Down gradient
Down gradient
Formation of
Completion
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Number of
Analyses
15
1
2
1
15
1
2
1
15
1
2
1
15
1
2
1
14
1
1
1
Number of
Analyses
Exceeding
Standard
— — —
5
___
1
1
2
Percent
Exceeding
Standard
__«
33
___
50
100
14
.
—
Maximum
Value
Obtained
(mg/1) I/
_«»
0.70
— — —
0.21
0.06
25.184
_ — —
— — —
— — —
4-73
-------
Pag* 2 of 3
TABLE 4-14
Site Name: Mexican Hat (Utah)
Data Evaluation: Site Water Quality Compared to U.S
plus Uranium and Molybdenum
Data Interval: 04/10/85 to 11/01/85
EPA Standards Not Included in 40 CFR 192.32(a)
Standard
Constituent (ag/1) I/
Manganese 0.05
Molybdenum 0 • 1°
Nitrate 2/ 44
pH 3/ 6.5 to 8.5
Sulfate 250
Hydraulic Flow
Relationship
Background
On-Site
Down gradient
Down gradient
Background
On-Site
Down gradient
Down gradient
Background
On-Site
Down gradient
Down gradient
Background
On-Site
Down gradient
Down gradient
Background
On-Site
Down gradient
Down gradient
Formation of
Completion
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Number of
Analyses
T K
15
1
1
15
1
2
1
15
1
2
1
15
1
1
15
1
2
1
Number of
Analyses
Exceeding
Standard
3
1
3_
1
6
1
1
i
JU
1 R
JLO
i
•)
Ł•
i
j.
Percent
Exceeding
Standard
20
100
50
100
40
100
100
6
50
100
100
100
100
Value
Obtained
(mg/1) i/
0.06
0.38
0.06
0.15
0.20
0.10
80.0
_ _—
10.24
12.28
*._«•
4090
3170
722
947
4-76
-------
TABLE 4-14
Site Name: Mexican Hat (Utah)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 04/10/85 to 11/01/85
Page 3 of 3
in 40 CFR 192.32(a)
Constituent
Sulfide
Total Solids
Uranium 4/
Zinc
I/ Values are
2/ Concentratj
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
On-Site
Down gradient
Down gradient
500 Background
On-Site
Down gradient
Down gradient
0.044 Background
On-Site
Down gradient
Down gradient
5 . 0 Background
On-Site
Down gradient
Down gradient
reported _ in mg/1 unless otherwise
Formation of
Completion
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Siltstone
Rico
Rico
indicated.
JVel of in mer/1
Number of
Analyses
15
1
2
1
15
1
2
1
15
1
2
1
15
1
2
1
1 fi Gem i *ra 1 or»H
Number of
Analyses
Exceeding
Standard
15
1
2
15
1
2
1
2
1
" _:.:_
„ „ n.
h 4*^ /^^\*sx^j^v*^*™-»
Percent
Exceeding
Standard
100
100
100
100
100
100
100
13
100
—
—
Maximum
Value
Obtained
(mg/1) I/
0.10
0. 10
0. 10
6550
1960
4250
1870
0.0512
OfiO9
. O \J ft
0.0334
V
Standard not exceeded.
egUlValent °f 0'044 -*/1' assumin* the bulk of uranium is U-238. All analyses are reported as
4-77
-------
4.9 MONUMENT VALLEY, ARIZONA - SUMMARY OF WATER QUALITY
Major hydrostratigraphic units at the Monument Valley site
are alluvium and dune sand, the Shinarump Member of the
Sinle Formation, the Moenkopi Formation, and the DeChelly
Sandstone Member of the Cutler Formation. The alluvium,
Shinarump and the DeChelly Sandstone are aquifers. The
MoeSSS! is an aguitard which separates the Shinarump from
the underlying DeChelly Sandstone.
The background water quality .in all three of the aquifers is
good. Only the alluvial aquifer has been appreciably
Iffected by the tailings. The alluvial groundwater is
unconfined and ranges from . approximately two feet to 45 feet
below the surface in the vicinity of the tailings.
Groundwater use near the site consists of two
alluvial wells which are used by local residents.
production wells are located on and down gradient of the
site The production wells supplied water for the former
milling operations but are not presently used. Two seeps
east of the tailings site are discharges of alluvial ground-
water and are used for watering livestock. Sampling of
these wells and seeps has not revealed the presence of any
contamination from the tailings.
Chromium exceeded the standard in some samples from all
three down gradient aquifers. The down gradient alluvium
had ?he highest value for chromium, as well as, the highest
percentage of samples exceeding the standard.
The gross alpha standard was exceeded in background samples
of the Ihinaiump Formation and the down gradient alluvium
and DeChelly Formation samples. The highest values obtained
were from the down gradient alluvium, in which the maximum
value exceeded the Standard by more than a factor of three.
One of nine radium background samples from the Shinarump
Formation exceeded the standard. This sample exceeded the
standard by a factor of less than two.
the
mobile contaminant plume will dissipate within the
in approximately 120 years.
4-78
-------
TABLE 4-15
Site Name:
Monument Valley (Arizona)
Page 1 of 10
4°
Constituent
Arsenic
Standard Hydraulic Flow
(mg/1) i/ Relationship
0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-site
Down gradient
Down gradient
Down gradient
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-79
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 2 of 10
Constituent
Barium
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
1.0
Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 9
of the Chinle
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 34
Shinarump member 12
of the Chinle
Formation
DeChelly member 4
of the Cutler
Formation
4-80
-------
TABLE 4-15
Site Name:
Monument Valley (Arizona)
Page 3 of 10
compared to u-s- EPA standards from 4° CFR i92-32(a)
Constituent
Cadmium
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.01 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium e
Shinarump member 10
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-81
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 4 of 10
Constituent
Chromium
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) l/
Alluvium 6
Shinarump member 10
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
_of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
12
1
27
6
25
0.09
0.07
0.07
4-82
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 5 of 10
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Gross Alpha
(excluding radon
and uranium)
15.0 pci/l
Background
Background
Alluvium
Shinarump member
of the Chinle
6
10
1
10
17.104
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
15
12
45.968
16.372
4-83
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 06/08/82 to 04/30/86
Page 6 of 10
EPA Standards from 40 CFR 192.32(a)
Constituent
Lead
Standard
(mg/1) I/
0.05
Hydraulic Flow
Relationship
Background
Background
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Alluvium 6
Shinarump member 10
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-84
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 7 of 10
Constituent
Mercury
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/l> I/
0.002 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 9
of the Chinle
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 34
Shinarump member 12
of the Chinle
Formation
DeChelly member 4
of the Cutler
Formation
4-85
-------
TABLE 4-15
Site Name: Monuaent Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 06/08/82 to 04/30/86
Page 8 of 10
EPA Standards from 40 CFR 192.32(a)
Constituent
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Ra-226 + Ra-228
(Radium)
5.0 pCi/1 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 9
of the Chinle
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 34
Shinarump member 12
of the Chinle
Formation
DeChelly member 3
of the Cutler
Formation
11
8.8
4-86
-------
TABLE 4-15
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 9 of 10
Constituent
Selenium
Standard
(mg/1) I/
0.01
Hydraulic Flow
Relationship
Background
Background
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Alluvium 7
Shinafump member 10
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-87
-------
TABLE 4-15
Site Naae: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/08/82 to 04/30/86
Page 10 of 10
Constituent
Silver
standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 9
of the Chinle
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 34
Shinarump member 12
of the Chinle
Formation
DeChelly member 4
of the Cutler
Formation
I/ Values are reported in mg/1 unless otherwise indicated.
Standard not exceeded.
4-88
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 1 of 15
Constituent
Chloride
Standard
(mg/1) I/
250
Hydraulic Flow
Relationship
Background
Background
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Alluvium 7
Shinarump member 10 — — • ---
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-89
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
plus Uraniuma and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 4 of 15
EPA Standards Not Included in 40 CFR 192.32(a)
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Hydrogen Sulfide 0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
i
Down gradient
Down gradient
Down gradient
Formation of Number of
Completion Analyses
Alluvium
Shiriarump member
of the Chinle
Formation
DeChelly member
of the Cutler
Formation
Alluvium
Shinarump member
of the Chinle
Formation
DeChelly member
of the Cutler
Formation
DeChelly member
of the Cutler
Formation
Alluvium
Shinarump member
of the Chinle
Formation
DeChelly member
of the Cutler
Formation
1
1
1
1
1
1
1
1
1
1
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (»g/l) !/
— — — — —
- —
___ — - —
— — — — —
— - —
___ ___ —
___ ___ ___
-: —
4-92
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 5 of 15
Constituent
Iron
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.30 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
10
0.33
0.31
4-93
-------
TABLE 4-16
Site Name; Monument Valley (Arizona)
Data Evaluation: Site Water Quality compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 6 of 15
Constituent
Manganese
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 10
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
70
0.10
50
50
0.09
0.21
20
7
44
46
37
0.58
0.17
0.11
4-94
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 7 of 15
EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
Molybdenum
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.10 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium" 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
1
4
2
1
37
14
14
40
44
50
50
83
84
93
100
0.11
0.22
0.19
0.19
0.16
0.21
0.35
0.25
0.24
4-95
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 8 of 15
Constituent
Nitrate 2/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
44
Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 10
of the Chinle
Formation
Dechelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
15
34
1200
4-96
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 9 of 15
Constituent
pH 3/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
6.5 to 8.5 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
.of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
"Formation
DeChelly member 8
of the Cutler
Formation
22
9.36
2
6
50
9.68
8.65
9.89
4-97
-------
TABLE 4-16
Sit« Names Monument Valley (Arizona)
Data Evaluation: Site Water Quality Coapared t
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 10 of 15
U.S. EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
Sulfate
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
250
Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
28.
63
3130
4-98
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 11 of 15
Constituent
Sulfide
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 9
of the Chinle
Formation
DeChelly member 7
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 34
Shinarump member 12
of the Chinle
Formation
DeChelly member 5
of the Cutler
Formation
3
7
2
1
1
6
28
7
50
77
57
50
50
16
75
82
58
100
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
4-99
-------
I
TABLE 4-16
Site Name: Monument Valley (Arizona) t m „„„ „, .
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 12 of 15
Constituent
Total Solids
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
500
Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
28
626
28
6
63
40
25
5590
730
563
4-100
-------
TABLE 4-16
Site Name: Monument Valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 13 of 15
Constituent
Uranium 4/
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.044 Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 7
Shinarump member 10
of the Chinle
Formation
DeChelly member 9
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium „ 44
Shinarump member 15
Of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
13
0.0514
4-101
-------
TABLE 4-16
Site Name: Monument valley (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
plus Uranium and Molybdenum
Data Interval: 06/08/82 to 04/30/86
Page 14 of 15
EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
Zinc
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
5.0
Background
Background
Background
Cross-gradient
Cross-gradient
Cross-gradient
On-Site
Down gradient
Down gradient
Down gradient
Alluvium 6
Shinarump member 10
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 4
Shinarump member 2
of the Chinle
Formation
DeChelly member 6
of the Cutler
Formation
DeChelly member 8
of the Cutler
Formation
Alluvium 44
Shinarump member 15
of the Chinle
Formation
DeChelly member 8
of the Cutler
Formation
4-102
-------
TABLE 4-16
Site Name: Monument Valley .(Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
plus Uranium and Holybedum
Data Interval: 06/08/82 to 04/30/86
Page 15 of 15
EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
— Standard not exceeded.
4-103
-------
4.10 RIVERTON, WYOMING - SUMMARY OF WATER QUALITY
The Riverton process site lies on the floodplain of the Wind
and Little Wind Rivers. The site rests on, in descending
order, recent alluvium and beds of the Wind River Formation.
There are two aquifers in the site vicinity; the water table
(unconfined)aquifer consisting of alluvium and the uppermost
sandstone of the Wind River Formation (2) the confined
aquifer consisting of deeper sandstone beds. Contamination
is restricted largely to the unconfined aquifer. Histor-
ically the unconfined aquifer within the plume area has had
limited use; currently, the aquifer is not being used in
this area. The confined aquifer does not appear to be
contaminated.
Groundwater sampling indicated that limits of concentration
of gross alpha were exceeded. The one on-site gravel
analyzed for gross alpha exceeded the standard by more than
a factor of 17. Concentrations of arsenic, chromium,
barium, silver, cadmium, mercury, radium, lead and selenium
were below the limits for the standard.
Groundwater discharges to the Little Wind River, approxi-_
mately 3000 feet from the site. Modeling indicates that it
will take 45 to 65 years for the mobile contaminants to
completely flush from the unconfined aquifer. Based on the
present location of the molybdenum plume relative to the
sulfate plume, it may take 200 to 300 years to flush molyb-
denum from the system.
4-104
-------
TABLE 4-17
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 12/02/83 to 06/05/85
Page 1 of 5
Constituent
Arsenic
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.05
Barium
1.0
Background
On-Site
On-Site
Down gradient
Down gradient
Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
4-105
-------
TABLE 4-17
site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 12/02/83 to 06/05/85
Page 2 of 5
Constituent
Cadmium
standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1)
Chromium
0.01 Background
On-Site
On-Site
Down gradient
Down gradient
0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
4-106
-------
TABLE 4-17
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 12/02/83 to 06/05/85
Page 3 of 5
Constituent
Standard
(mg/1) l/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses•
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Gross Alpha
(excluding radon
and uranium)
Lead
15.0 pci/l Background
On-Site
On-Site
Down gradient
Down gradient
0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 9
gravel, poorly
graded
Gravel or sandy l
gravel, poorly
graded
Sandstone 10
Gravel or sandy l
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
100
10
260.8
65.2
4-107
-------
TABU: 4-17
site Name: Riverton (Wyoming) _ ,,,_\
Data Evaluation: Site Water Quality Compared to U.S. EPA standards from 40 CFR 192.32(a)
Data interval: 12/02/83 to 06/05/85
Page 4 of 5
Constituent
Mercury
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1)
Ra-226 + Ra-228
(Radium)
0.002 Background
On-Site
On-Site
Down gradient
Down gradient
5.0 pCi/1 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 16
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 2 2/
gravel, poorly
graded
Sandstone 7
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
4-108
-------
TABLE 4-17
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 12/02/83 to 06/05/85
Page 5 of 5
Constituent
Selenium
Standard Hydraulic Flow
(mg/1) I/ Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Silver
0.01 Background
On-Site
On-Site
Down gradient
Down gradient
0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 16
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Analyses for Ra-226 only.
Standard not exceeded.
4-109
-------
TABLE 4-18
Data Evaluation* Site Water5Quality Coapared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 1 of 8
Constituent
Chloride
Standard
(ng/D
Hydraulic Flow
Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
.Value
Obtained
(mg/1) I/
250
Copper
1.0
Background
On-Site
On-Site
Down gradient
Down gradient
Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 9
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 2
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
4-110
-------
TABLE 4-18
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 2 of 8
in 40 CFR 192.32(a)
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Fluoride 1.4 Background
On-Site
On-Site
Down gradient
Down gradient
Hydrogen Sulfide 0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Formation of Number of
Completion Analyses
Gravel or sandy
gravel , poorly
graded
Gravel or sandy
gravel, poorly
graded
Sandstone
Gravel or sandy
gravel , poorly
graded
Sandstone
Gravel or sandy
gravel, poorly
graded
Gravel or sandy
gravel, poorly
graded
Sandstone
Gravel or sandy
gravel, poorly
graded
Sandstone
9
3
16
1
2
1
1
1
1
1
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard Standard (mg/1) I/
™^*™ ~™™ • • • •
— — — _ — -, .....
»— »— <_>*•• ••«
— — — —__ «._«
— — — ___ ...
« — — .»•*• «_ _
•w ...... _«•» «__
— — — ™ ..__
4-111
-------
TABLE 4-18
Site Name: Riverton (Wyoming) j J „,,„„„„,,
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 3 of 8
Constituent
Iron
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
.Manganese
0.30 Background
On-Site
On-Site
Down gradient
Down gradient
0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy • 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
21
1
19
0.75
100
100
100
100
2.26
0.23
5.20
1.05
4-112
-------
TABLE 4-18
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 4 of 8
Constituent
Molybdenum
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Nitrate 2/
0.10 Background
On-Site
On-Site
Down gradient
Down gradient
44 Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 9
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
19
1.69
4-113
-------
TABLE 4-18
Site Kane: Rivarton (Wyoming) . ,
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.
plus Uranium and Holybdenum
Data Interval: 12/02/83 to 06/05/85
Page 5 of 8
Constituent
PH 3/
Standard
(mg/1) l/
6.5 to 8.5
Sulfate
250
Hydraulic Flow
Relationship
Background
On-Site
On-Site
Down gradient
Down gradient
Background
On-Site
On-Site
Down gradient
Down gradient
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Gravel or sandy 12
gravel, poorly
graded
Gravel or sandy 1
gravel, poorly
graded
Sandstone 15
Gravel or sandy 3
gravel, poorly
graded
Sandstone 3
Gravel or sandy 9
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 2
19
1
Percent
Exceeding
Standard
8
Maximum
Value
Obtained
(mg/1) y
9.35
100
22
100
90
100
50
12.26
376
577
747
461
286
4-114
-------
TABLE 4-18
Site Name: Riverton (Wyoming)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 6 of 8
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Sulfide 0.05 Background
On-Site
On-Site
Down gradient
Down gradient
Total Solids 500 Background
On-Site
On-Site
Down gradient
Formation of Number of
Completion Analyses
Gravel or sandy
gravel , poorly
graded
Gravel or sandy
gravel , poorly
graded
Sandstone
Gravel or sandy
gravel , poorly
graded
Sandstone
Gravel or sandy
gravel , poorly
graded
Gravel or sandy
gravel , poorly
graded
Sandstone
Gravel or sandy
9
1
7
1
3
9
3
21
1
Number of
Analyses
Exceeding
Standard
9
7
1
3
2
3
19
1
Percent
Exceeding
Standard
100
—
100
100
100
22
100
90
100
Maximum
Value
Obtained
(mg/1) I/
0.10
— — —
0.10
0.10
0.10
950
1410
1450
1100
Down gradient
gravel, poorly
graded
Sandstone
100
1172
4-115
-------
TABLE 4-18
Site Naaa: Rivarton (Wyoming)
Data Evaluation: Site Water Quality Compared to
plus Uraniua and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 7 of 8
U.S. EPA standards Not included in 40 CFR 192.32(a)
Constituent
Uranium 4/
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
•Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
0.044
Zinc
5.0
Background
On-Site
On-Site
Down gradient
Down gradient
Background
On-Site
On-Site
Down gradient
Down gradient
Gravel or sandy 9
gravel, poorly
graded'
Gravel or sandy 2
gravel, poorly
graded
Sandstone 13
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
Gravel or sandy 8
gravel, poorly
graded
Gravel or sandy 3
gravel, poorly
graded
Sandstone 21
Gravel or sandy 1
gravel, poorly
graded
Sandstone 3
100
15
0.415
0.305
4-116
-------
TABLE 4-18
Site Name: Riverton (Wyoming)
Data Evaluation: site Water Quality Compared to U.S. EPA Standards Not Included
plus Uranium and Molybdenum
Data Interval: 12/02/83 to 06/05/85
Page 8 of 8
in 40 CFR 192.32(a)
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding'
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
Standard not exceeded.
4-117
-------
4.11 SALT LAKE CITY, UTAH - SUMMARY OF WATER QUALITY
The groundwater regime at the Vitro site is generally
characterized by two aquifer systems, a near-surface
unconfined system and a deeper confined system. Near the
site, both aquifers flow generally to the west-northwest.
The unconfined aquifer discharges into local surface water
courses.
Water in the unconfined aquifer, is of brackish quality with
high total dissolved solids, generally 2000 ppm or greater,
and sulfates on the order of 800 ppm or greater. Due to its
poor quality and low yields, this water has only very
limited use. Water in the confined aquifer generally has
dissolved solids concentrations of about 300 ppm and a
sulfate content of about 20 ppm. This aquifer is an impor-
tant source of water for domestic, agricultural and indus-
trial uses in the Salt Lake Valley.
In the unconfined aquifer, arsenic, iron and manganese
values exceeded standards in some up-, cross- and down-
gradient samples, with no clear trend evident. Gross alpha
and radium (Ra-226 and 228) values also exceeded standards
in some up-, cross- and downgradient samples, with signif-
icantly higher values in downgradient samples. Some samples
from up-, cross- and downgradient exceeded standards for
total dissolved solids, chloride and sulfate, with a larger
percentage of samples exceeding standards and somewhat
higher values in downgradient samples.
In the confined aquifer, some downgradient samples exceeded
standards for total dissolved solids and sulfate. Iron
values exceeded standards in up-, cross- and downgradient
samples, but the percentage of samples exceeding standards
was higher and the extent of the difference between the
measured values and the standards was greater in the down-
gradient samples.
The unconfined groundwater aquifer discharges to the Jordan
River and Mill Creek. Contaminant plumes have not been
modeled.
4-118
-------
TABLE 4-19
Stl SuatiS:LIi?eCWa?erUQuality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 1982 and 1983
Page 1 of 2
standard
Constituent (mg/1) I/ Aquifer
Arsenic 0.05 Unconfined
Confined
Barium 1 . 0 Unconfined
Confined
Cadmium 0.01 Unconfined
Confined
Chromium 0.05 Unconfined
Confined
Gross Alpha 15.0 pCi/1 Unconfined
(excluding radon
and uranium)
Confined
Lead 0.05 Unconfined
Confined
Hydraulic Flow 1
Relationship i
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
lumber of
Analyses
14
8
29
3
3
14
14
8
29
3
3
13
14
8
29
3
3
13
14
8
29
3 - -
3
13
10
8
29
3
2
13
14
8
29
3
3
13
Number of
Analyses
Exceeding
Standard
11
4
—
—
__~
— -
—
---
---
___
---
—
-— -
---
__«
___
1
___
—
---
___
6
3
24
2
1
4
2
---
---
---
---
Percent
Exceeding
Standard
79
14
__ -.
— — —
^^**
- — —
" ~~
— -» —
— — —
«_•
-
" ~T""
---
- , ^ __.
— — —
__••
12
---
~~r
, , ---
~m*m*
60
37
83
67
50
31
14
T — ""
__'—
"•""•
---
-~~
Maximum
Value
Obtained
(mg/1) I/
0.245
0.5
«^«
_«••
—
•™~~
™ ~~
«w
— — —
—
•• — —
•*"•""
"••" —
~~~
"*"*""
—
0.08
— •••
__•
•• — — —
600
85.2
1181
30
30
100
0.3
...
•*„•"
""•"•
— — -
~~~
4-119
-------
TABLE 4-19
DaS Sua?iJn:L|iteCS4rUSuility Compared to U.S. EPA Standards from 40 CFR 192.32U)
Data Interval: 1982 and 1983
Page 2 of 2
Standard
Constituent (mg/1) i/
Mercury 0.002
Ra-226 + Ra-228 5.0 pCi/1
(Radium)
Selenium 0.01
Silver 0.05
Aquifer
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Hydraulic Flow I
Relationship I
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradien
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
lumber of
Uialyses
14
8
29
3
3
13
10
8
27
3
2
12
14
8
29
3
3
13
14
8
29
3
3
13
Humber of
Analyses
Exceeding
Standard
1
— — «
___
V — —
1
3
5
___
1
1
___
---
— —
---
*•"*""
— T
---
---
__-
""
Percent
Exceeding
Standard
3
w«w
~~*"
10
37
18
— ~—
50
8
.
— "•"•
— __
"~~
"*™~
'
-•—
"•""
~™*~
— .— -»
— ••••
Maximum
Value
Obtained
(mg/1) I/
0.003
___
14
12.5
114
51
.1
91
.1
~*"~
«^«
""""™
^^^
^^^
"™^^
•"•••
y Values are reported in mg/1 unless otherwise indicated.
— Standard not exceeded.
4-120
-------
TABLE 4-20
Site Name: Salt Lake City, Utah .
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in
plus Uranium and Molybdenum
Data Interval: 1982 and 1983
Page 1 of 3
40 CFR 192.32(a)
Standard
Constituent (mg/1) I/
Chloride 250
Copper 1 . 0
Fluoride 1 . 4
Hydrogen Sulfide 0.05
Iron 0.3
Manganese 0.05
Aquifer
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Hydraulic Plow 1
Relationship i
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient ,
Crossgradient
Downgradient
Upgradient
Crossgradient,
Downgradient
Upgradient
Crossgradient
Downgr adient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
dumber of
Analyses
9
5
21
3
2
14
14
8
29
3
3
13
1
4
5
1
1
4
1
4
6
1
1
4
15.
8
35
3
. 3.
17
8
6
18
1
2
10
Number of
Analyses
: Exceeding
Standard
5
5
17
---
5
— —
—
—-—
— :_
— — —
5
___
---
2
---
1
1
8
6
25
; i
2
11
7
6
17
'2
10
Percent
Exceeding
Standard
56
100
81
— _
___
36
— —
— — —
— — —
__- -
_««
— — —
100 .
-- —
___
— — —
33
— — —
100
25
53
75
71 '
33
67
65
87
100
94
---
100
100
Maximum
Value
Obtained
(mg/1) I/
4900
2883
5400
___
__«
410
™ — ™
___
__«
--»-
fm — «
"••"""
6.1
"•""•
— """
.__ .
_«
0.08
" — —
0.09
0.07
70
44
58
0.61
0.92
4.6
1.6
1.85
4.02
—"••
1.5
0.60
4-121
-------
TABLE 4-20
Site Name: Salt Lake City, Utah ...
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32U)
plus Uranium and Molybdenum
Data Interval: 1982 and 1983
Page 2 of 3
Standard
Constituent (mg/1) I/
Molybdenum 0.10
Nitrate 2/ 44
pH 3/ 6.5 to 8.5
Sulfate 250
Total Solids 500
Uranium 4_/ 0.044
Aquifer
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Unconfined
Confined
Hydraulic Flow 1
Relationship J
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
Upgradient
Crossgradient
Downgradient
{umber of
taalyses
14
8
29
3
3
13
5
6
12
3
2
6
12
6
25
3
2
14
9
5
21
3
2
14
12
5
25
3
2
15
11
8
33
3
2
16
Number of
Analyses
Exceeding
Standard
1
1
___
4
5
18
5
10
5
22
---
---
11
1
24
---
---
Percent
Exceeding
Standard
3
17
— — —
44
100
86
---
---
36
83
100
88
___
_«._
73
12
73
___
---
___
Maximum
Value
Obtained
(mg/1) I/
0.2
™.~™
4300
2000
7800
___
~ — ""
590
16100
6002
21000
— — —
— — —
1800
31.1
2.24
__ —
— — —
w«
4-122
-------
TABLE 4-20
Site Name: Salt Lake City, Utah
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: '1982 and 1983
Page 3 of 3
Constituent
Zinc
Standard Hydraulic Flow
(mg/1) I/ Aquifer Relationship
5 . 0 Unconf ined Upgradient
Crossgradient
Downgradient
Confined Upgradient
Crossgradient
Downgradient
Number of
Analyses
14
8
29
3
3
13
Number of
Analyses
Exceeding
Standard
1
Percent
Exceeding
Standard
3
Maximum
Value
Obtained
(mg/1) I/
110
^/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate
at a level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3_/ pH reported in standard units.
4/ 30 pci/l of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are
reported as total uranium in mg/1.
— Standard not exceeded.
4-123
-------
4.12 SHIPROCK, NM - SUMMARY OF WATER QUALITY
The Shiprock site is in northwestern New Mexico and rests on
the escarpment above the floodplain of the San Juan River.
The remedial action is complete. The underlying groundwater
(divided into two units) is definitely contaminated.
Groundwater in the floodplain unit has been used and is
potentially useable in the future; contamination in the
floodplain appears tq be relict, i.e., from past discharges.
A key issue is the extent and characteristics of the flood-
plain contamination. The second groundwater unit is perched
within the soils and fractured Mancos Shale on the escarp-
ment above the floodplain.
Chromium, selenium and silver exceeded the standard for some
samples. Eight out of 29 analysis for chromium down gradi-
ent samples exceed the standard. One of 29 down gradient
samples exceeded the standard for silver. Thirteen of 77
down gradient selenium samples exceeded standards. Arsenic,
barium, cadmium, gross alpha, lead, mercury, and radium
concentrations are within limits of the standards.
Contaminated water occurs in the floodplain. Groundwater in
the alluvium discharges to the San Juan River. The contami-
nant plume has not been modeled; existing data show little
if any flushing of contaminants in the alluvium.
4-124
-------
TABLE 4-21
Site Name: Shiprock (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 10/16/84 to 09/20/86
Page 1 of 2
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha
(excluding radon
and uranium)
Lead
Mercury
Standard
(mg/1) I/
0.05
1.0
0.01
0.05
15.0 pCi/1
0.05
0.002
Hydraulic Flow
Relationship
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
2
29
2
29
2
77
2
29
1
1
2
29
2
29
Number of
Analyses
Exceeding
Standard
8
— — —
— — —
Percent
Exceeding
Standard
—
—- •
___
27
___
Maximum
Value
Obtained
(mg/1) I/
— —
0.11
• w*»
—
4-125
-------
TABLE 4-21
Site Name: shiprock (New Mexico)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 10/16/84 to 09/20/86
Page 2 of 2
Constituent
Ra-226 + Ra-22Ł
(Radium)
Selenium
Silver
Standard Hydraulic Flow
(mg/1) I/ Relationship
t 5.0 pci/l Upgradient
Down gradient
0 . 01 Upgradient
Down gradient
0 . 05 Upgradient
Down gradient
Formation of Number of
Completion Analyses
Alluvium 2 2/
Alluvium 23
Alluvium 2
Alluvium 77
Alluvium 2
Alluvium 29
Number of Maximum
Analyses Percent Value
Exceeding Exceeding Obtained
Standard standard (mg/1) !/
-— ___ ___
13 16 0.91
1 3 0.10
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Analyses for Ra-226 only.
Standard not exceeded.
4-126
-------
TABLE 4-22
Site Name: Shiprock (New Mexico) .
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molydbenum
Data Interval: 10/16/84 to 09/20/86
Page 1 of 2
Constituent
Chloride
Copper
Fluoride
Hydrogen Sulfide
Iron
Manganese
Molybdenum
Nitrate 2/
Standard
(mg/1) I/
250
1.0
1.4
0.05
0.30
0.05
0.10
44
Hydraulic Flow
Relationship •
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of
Analyses
2
77
2
77
2
77
1
1
2
77
2
77
2
77
2
77
Number of
Analyses
Exceeding
Standard
27
— — —
48
1
18
2
76
1
53
57
Percent
Exceeding
Standard
35
— — —
62
— — —
50
23
100
98
50
69
77
Maximum
Value
Obtained
(mg/1) I/
2200
14.0
1.14
2.05
0.74
9.60
0.16
0.44
3600
4-127
-------
TABLE 4-22
Site Na»e; Shiprock (New Mexico)
Data Evaluation: Site Water Quality compared to U.S. EPA Standards Not Included in 40 CFR I92.32(a)
plus Uranium and Molybdenum
Data Interval: 10/16/84 to 09/20/86
Page 2 of 2
Constituent
pH 3/
Sulfate
Sulfide
Total Solids
Uranium 4/
Zinc
Standard Hydraulic Flow
(mg/1) I/ Relationship
6.5 to 8.5
250
0.05
500
0.044
5.0
Upgradient
Down -gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Upgradient
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Number of Maximum
Analyses Percent Value
Number of Exceeding Exceeding Obtained
Analyses Standard Standard (mg/1) I/
2
77
2
77
1
23
2
77
1
71
2
77
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium
total uranium in mg/1.
Standard not exceeded.
.__
77
1
23
1
77
55
—
___
100 19,
100
200
50
100 32,
77
concentration of nitrate
is U-238. All analyses
___
200
0.10
0.10
534
600
7.21
as nitrate at a
are reported as
4-128
-------
4.13 TUBA CITY, ARIZONA - SUMMARY OF WATER QUALITY
The Tuba City site is located in northeastern Arizona about
five miles east of Tuba City. The site rests on the Nava^o
Sandstone which contains the primary water source in the
area. Background monitor wells reveal good water quality
(TDS < 500 mg/1) with minor exceptions. The tailings pile
has contaminated approximately one billion gallons of
groundwater. :
Cadmium concentrations were higher in on-site and down
gradient samples than in background or upgradient samples.
Seven of 48 down gradient analyses for chromium and four of
13 upgradient analyses for radium exceeded the limit for the
standard. Maximum selenium concentrations exceeded the
standard by a factor of 6. One of 4 on-site samples^for
gross alpha, as well as one of 14 down gradient samples,
exceed the standard for gross alpha.
Groundwater flow and at least partial discharge of contami-
nated water is into the Moenkopi Wash, about 2 miles from
the edge of the tailing pile. Modeling shows discharge of
the trailing edge of the mobile contaminant plume to Moen-
kopi Wash in 300 years. Discharge of the uranium plume was
not modeled but is estimated to be several hundred years
after the mobile plume.
4-129
-------
TABLE 4-23
Site Name: Tuba City (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 06/09/82 to 04/11/86
Page 1 of 3
EPA standards from 40 CFR 192.32(a)
Constituent
Arsenic
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Barium
Cadmium
Chromium
0.05 Background .
Upgradient
On-Site
Down gradient
1.0 Background
Upgradient
On-Site
Down gradient
0.01 Background
Upgradient
On-Site
Down gradient
0.05 Background
Upgradient
On-Site
Down gradient
Navajo Sandstone 6
Navajo Sandstone 13
Navajo Sandstone 6
Navajo Sandstone 20
Navajo Sandstone 6
Navajo Sandstone 13
Navajo Sandstone 6
Navajo Sandstone 20
Navajo Sandstone 10
Navajo Sandstone 18
Navajo Sandstone 6
Navajo Sandstone 48
Navajo Sandstone 10
Navajo Sandstone 18
Navajo Sandstone 6
Navajo Sandstone 48
4
10
66
20
14
0.031
0.039
0.08
4-130
-------
TABLE 4-23
Site Name: Tuba City (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/09/82 to 04/11/86
Page 2 of 3
Constituent
Gross Alpha
(excluding radon
and uranium)
Lead
Mercury
Ra-226 + Ra-228
(Radium)
Selenium
Standard Hydraulic Flow
(mg/1) I/ Relationship
15.0 pCi/1 Background
Upgradient
On-Site
Down gradient
0 . 05 Background
Upgradient
On-Site
Down gradient
0 . 002 Background
Upgradient
On-Site
Down gradient
5.0 pCi/1 Background
Upgradient
On-Site
Down gradient
0.01 Background
Upgradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
4
9
4 '
14
6
13
6
20
6
13
6
20
6
13
6
20
10
18
6
48
Number of
Analyses
Exceeding
Standard
___
1
1
___
—
__._
1
___
___
1
___
4
— — —
1
- —
6
10
Percent
Exceeding
Standard
—
25
7
___
,. - - —
— -
5
___
— -
5
30
— — —
10
—
100
20
Maximum
Value
Obtained
(mg/1) I/
—
—
33.2
27.2
___
— - •
0.06
___
- —
—
0.0029
___
7.0
— -
— — —
0.018
0.039
0.066
4-131
-------
TABLE 4-23
Site Mama: Tuba city (Arizona)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 06/09/82 to 04/11/86
Page 3 of 3
EPA Standards from 40 CFR 192. 32 (a)
Constituent
Silver
Standard
(mg/1) I/
0.05
Hydraulic Flow
Relationship
Background
Upgradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
8
13
6
33
Number of
Analyses
Exceeding
Standard
1
Percent
Exceeding
Standard
12
Maximum
Value
Obtained
(mg/1) I/
0.10
I/ Values are reported in mg/1 unless otherwise indicated.
Standard not exceeded.
4-132
-------
TABLE 4-24
Site Name: Tuba City (Arizona)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/09/82 to 04/11/86
Page 1 of 4
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Chloride 250
Copper 1 . 0
Fluoride . 1.4 .
Hydrogen Sulfide 0.05
Background
Upgradient
On-Site
Down gradient
Background
Upgradient
On-Site
Down gradient
Background
Upgradient
On-Site
Down gradient
Background
Upgradient
On-Site
Down gradient
Number of Maximum
Analyses Percent Value
Formation of Number of Exceeding Exceeding Obtained
Completion Analyses Standard Standard (mg/1) I/
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone -
Navajo Sandstone
10
17
48
8
13
6
33
6
12 2 16 4.60
20 —
1 — — — «•»«• __«
1 — — ; —
4-133
-------
TABIŁ 4-24
site Hams: Tuba city (Arizona)
Data Evaluation: Site Hater Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/09/82 to 04/11/86
Pag* 2 of 4
Constituent
Iron
Manganese
Molybdenum
Nitrate 2/
Standard Hydraulic Flow
(mg/1) I/ Relationship
0.30 Background
Upgradient
On-Site
Down gradient
0.05 Background
Upgradient
On-Site
Down gradient
0 . 10 Background
Upgradient
On-Site
Down gradient
44 Background
Upgradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
8
13
6
33
8
9
6
33
8
18
6
48
10
17
6
48
Number of
Analyses
Exceeding
Standard
__—
3
3
1
___
1
6
11
3
5
1
28
___
6
24
Percent
Exceeding
Standard
___
23
50
3
___
11
100
33
38
27
17
58
___
100
50
Maximum
Value
Obtained
(mg/1) I/
___
2.25
1.14
1.96
___
0.10
2.40
0.35
0.21
0.20
0.21
0.24
___
1800
1500
4-134
-------
TABLE 4-24
Site Name: Tuba City (Arizona)
Data Evaluation: Site Hater Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/09/82 to 04/11/86
Page 3 of 4
Constituent
PH 3/
Sulfate
Sulfide
Total Solids
Standard Hydraulic Flow
(mg/1) I/ Relationship
6.5 to 8.5 Background
Upgradient
On-Site
Down gradient
250 Background
Upgradient
On-Site
Down gradient
0.05 Background
Upgradient
On-Site
Down gradient
500 Background
Upgradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
Navajo Sandstone
10
18
6
48
10
17
6
48
4
8
4
17
10
13
6
48
Number of
Analyses
Exceeding
Standard
7
1
4
25
— — —
6
20
4
8
4
17
___
1
6
29
Percent
Exceeding
Standard
70
5
66
52
___
- —
100
41
100
100
100
100
___
7
100
60
Maximum
Value
Obtained
(mg/1) I/
10.10
8.79
6.19
6.33/12.75
___
2600
4010
0.10
0.10
0.10
0.10
___
600
7000
8550
4-135
-------
TABLE 4-24
Site Name: Tuba City (Arizona)
Data Evaluation: Site Hater Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/09/82 to 04/11/86
Page 4 of 4
Constituent
Uranium 4/
Standard
(mg/1) I/
0.044
Hydraulic Flow
Relationship
Background
Upgradient
On-Site
Down gradient
Formation of Number of
Completion Analyses
Navajo Sandstone 8
Navajo Sandstone 17
Navajo Sandstone 4
Navajo Sandstone 45
Number of
Analyses
Exceeding
Standard
4
19
Percent
Exceeding
Standard
100
42
Maximum
Value
Obtained
(mg/1) I/
2.40
0.21
Zinc
5.0
Background
Upgradient
On-Site
Down gradient
Navajo Sandstone 8
Navajo Sandstone 9
Navajo Sandstone 6
Navajo Sandstone 33
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate at a
level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are reported as
total uranium in mg/1.
-— Standard not exceeded.
4-136
-------
GREEN RIVER—SUMMARY OF WATER QUALITY
This site is located in the floodplain of Brown's Wash, an
intermittent tributary of the Green River which flows southward
and discharges into the Colorado River about 60 miles south of
Green River, Utah. The site is on the nose of shallow north
plunging anticline that is repeated by the arcuate
eastnortheast-westnorthwest trending Little Grand Wash fault
three miles south of the site. Sedimentary units of Cretaceus
and Jurassic age outcrop in the area; units at the site include
the Quaternary Brown's Wash alluvium underlying the tailings
pile and alluvial terrace deposits beneath the proposed disposal
site. These are underlain by the Tununk Shale Member of the
Mancos Shale, the Dakota Sandstone and the Cedar Mountain
Formation, all of Cretaceous age. Four distinct water-bearing
units were defined within the upper 200 feet of Quaternary and
Cretaceous sediments at the site. These are, from the surface
down:
-the zero to 35 feet thick Brown's Wash alluvium is
comprised of silt, sand, gravel and some small cobbles and
extends 300 to 400 feet on either side of Brown's Wash. A
paleochannel of Brown's Wash has eroded away the Dakota
Sandstone beneath the tailings site, and the alluvium directly
overlies shale of the Cedar Mountain Formation; this unit does
not extend south of the tailings pile or under the proposed
disposal site. Groundwater of this unit is locally perched;
-the upper-middle unit is comprised of up to 30 feet of
alternating layers of shale, limestone and mudstone of the Cedar
Mountain Formation; this unit is continuous beneath both the
existing and proposed tailings sites;
-the lower-middle unit is a relatively thick but laterally
limited sandstone and conglomerate channel deposit within the
Cedar Mountain Formation; this unit intertongues with the
middle-upper unit and also is continuous beneath both tailings
sites;
-the bottom unit is the 15 to 25'feet thick Buckhorn
Conglomerate Member of the Cedar Mountain Formation; this basal
sandstone and sandstone conglomerate unit is confined by
overlying shale and mudstone and is continuous beneath both
tailings sites.
Contamination from the tailings pile is confined to the upper
two units by strong upward hydraulic gradients between the
upper-middle unit and the underlying units; the maximum depth of
contamination at the site is about 65 feet (DOE-88). In both
the top and upper middle units gross alpha activity, molybdenum,
nitrate, selenium and uranium exceed background levels and
proposed EPA and State of Utah groundwater standards beneath
and downgradient of the tailings.
4-137
-------
TABLE 4-26 (continued)
qihe Name: Green Rivet (Utah)
Ilia Elation: Site Water Quality Compared to 0.
plus Uranium and Molybdenum
Data Interval: 7/14/82 - 1/12/88
S. EPA Standards Not Included in 40 CFR 192.32(a)
Constituent
Manganese
Standard
(rag/1) I/
0.05
Molybdenum
0.10
Hydraulic Flow
Relationship
Background
Upgradient
Cross-gradient
On-site
Down gradient
Background
Upgradient
Cross-gradient
On-site
Down gradient
Formation of Number of
Completion Analyses
.___——————-—————•
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
. Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
____.—-.———
13
4
9
10
2
6
5
5
21
6
4
2 - - - -
16
2
6
13
4
9
10
2
6
5
5
21
6
4
2
16
2
6
Number of
Analyses
Exceeding
Standard
_ — —
1
—
— — —
— — —
11
0
Ł.
— — —
«~.~
*L
—
• — — ~
Maximum
Percent Value
Exceeding Obtained
Standard (mg/1) I/
50
78
40
52
33
31
Oft
•J O
44
10
50
40
40
38
JO
100
50
0.06
0.21
0.49
___
..__
0.87
0.98
2.3
— — —
0.21
_. — —
— . — —
0.20
0.22
0.14
0.11
____
0.13
0.15
0.27
0.20
_._
0.104
_ — —
'
4-146
-------
TABLE 4-26 (continued)
Site Name: Green River (Utah)
Data Evaluation: Site Water Quality Compared to U. S. EPA Standards Not Included in 40 CPR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 7/14/82 - 1/12/88
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Nitrate 2/ 44 Background
Upgradient
Cross-gradient
On-site
Down gradient
pH 3/ 6.5-8.5 Background
Upgradient
Cross-gradient
On-site
Down gradient
Formation of l
Completion I
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
lumber of
Analyses
13
4
9
10
2
6
5
5
21
6
4
2
16
2
6
13
4
9
10
2
6
5
5
21
6
4
2
16
2
6
Number of
Analyses
Exceeding
Standard
3
2
6
2
943440
6
2
6
1
2
1
Percent
Exceeding
Standard
23
50
67
___
100
100
13
60
17
13
17
Maximum
Value
Obtained
(mg/1) I/ .
140
93
173
975
2480
•
71
11.61
8.65
__— —
___
— — _
9.08
8.84
4-147
-------
TABLE 4-26 (continued)
Site Name: Green River (Utah)
Data Evaluation: Site Water Quality Compared to U. S. EPA Standards Not Included in 40 CFR 192.32{a)
plus Uranium and Molybdenum
Data Interval: 7/14/82 - 1/12/88
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Sulfate 250 Background
Upgradient
Cross-gradient
On-site
Down gradient
Total Solids 500 Background
Upgradient
Cross-gradient
On-site
Down gradient
Formation of b
Completion ?
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
Alluvium
Shale
Conglomerate
Sandstone
Shale
Sandstone
Alluvium
Conglomerate
Alluvium
Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
lumber of
analyses
13
4
9
10
2
6
5
5
21
6
4
2
16
2
6
13
4
9
10
2
6
5
5
21
6
4
2
16
2
6
Number of
Analyses
Exceeding
Standard
13
4
9
10
2
4
5
5
21
7
4
2
16
2
6
13
4
9
10
2
6
5
5
21
7
4
2
16
2
vS
Percent
Exceeding
Standard
100
100
100
100
100
67
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Maximum
Value
Obtained
(mg/1) I/
6210
3940
4600
1193
4160
674
6280
700
6890
3610
2570
5000
3270
572
2120
9560
7300
7980
2480
9540
2170
10400
2120
10800
7160
4790
8030
6200
2930
3820
4-148
-------
TABLE 4-26 (continued)
Site Name: Green River (Utah)
Data Evaluation: Site Water Quality Compared to U. S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 7/14/82 - 1/12/88
Standard Hydraulic Flow
Constituent (mg/1) I/ Relationship
Uranium 4/ 0.044 Background
Upgradient
Cross-gradient
Ofi-site
Down gradient
:
-------
TABLE 4-26 (continued)
Site Name: Green River (Otah)
Data Evaluation: Site Water Quality Compared to U. S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 7/14/82 - 1/12/88
Constituent
Standard
(mg/1) V
Hydraulic Flow
Relationship
Formation of Number of
Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
On-site
Down gradient
Alluvium
' Shale
Conglomerate
Alluvium
Shale
Conglomerate
Sandstone
2i
6
4
2 — :-
16
2 — -
6 — '.-
I/ Values are reported in mg/1 unless otherwise indicated. •2/ Concentrations of nitrate as nitrogen at a level
of 10 mg.l is equivalent to concentration of nitrate as nitrate at a level of, 44 mg/1. All analyses are reported in
terms of nitrate as nitrate. 3/ pH reported in standard units. 4/ 30 pCi/1 of uranium is equivalent, of 0.044
mg/1, assuming the bulk of uranium is U-238. All analyses are reported as total uranium in mg/1. Standard not
exceeded.
4-150
-------
RIFLE (OLD AND NEW SITES) - SUMMARY OF WATER QUALITY
Both sites are located on the floodplain alluvium of the
Colorado River valley. Of the four aquifers in the Rifle
area, only two are affected by the tailings piles - the
unconfined alluvium and the underlying Wasatch Formation.
(DOE 87)
The alluvial aquifer is about 20 feet thick at the old site and
25 to 30 feet thick at the new site, with depths to water
ranging from 2 to 12 feet below land surface. Recharge of the
aquifer is primarily from the Colorado River and its
tributaries; discharge at the site is primarily to the Colorado
River, though there is some groundwater flow between the
alluvial aquifer and the underlying Wasatch aquifer. Water
levels are influenced by the Colorado River and fluctuate more
than 7 feet annually, being highest in the summer and lowest in
the winter. Groundwater flow is generally westward, roughly
parallel to the Colorado River channel. Discharge from a
drainage ditch at the north edge of the pile at the old site
percolates through the alluvium, causing a groundwater mound
beneath the pile in that area.
Ground water within the Wasatch Formation is confined by shales
and claystones of low permeability, interbedded with more
permeable sand-stones. Hydraulic heads are 10 to 20 feet above
the Wasatch-alluvium contact. The primary recharge area for
the Wasatch is probably the Grand Hogback, an area of nearly
vertical strata. Flow seems to be generally westward but is
poorly defined because of anomalous water levels resulting from
the discontinuous character of the Wasatch strata. Drainage is
to the alluvial aquifer along the Colorado River and, probably,
to its tributaries.
In the alluvial aquifer, analsyes show that sodium and calcium
are the dominant cations and sulfate and bicarbonate are the
dominant anions. The water is neutral pH and has a mean TDS
concentration of 1900 mg/1. Fluoride exceeds the EPA primary
drinking water standards in one well at the new site.Gross
alpha levels exceeded EPA primary standards in a number of
samples but are believed to result from the high levels of
naturally occurring uranium in the water. Manganese, iron and
chlorine levels in several wells and sulfate and TDS levels in
nearly all of the wells exceeded EPA secondary standards. Even
though much of the alluvial water in the area is in Use
Category 1 under the Colorado classification system, it may not
be suitable for domestic purposes because of the high levels of
natural contaminants.
The Wasatch aquifer is much higher in sodium and chloride and
lower in calcium and sulfate than the alluvial aquifer. The
water, is slightly alkaline and has a mean TDS concentration of
about 3600 mg/1. Back-ground levels for some constituents
4-151
-------
exceed EPA primary drinking water standards: barium (2 of 7
samples), radium-226 and radium-228 combined (1 of 5 samples),
fluoride (1 of 7 samples). Also, background levels exceed EPA
secondary drinking water standards for several constituents:
chloride (17 of 19 samples), pH was over 8.5 in 7 samples,
sulfate (4 of 19 samples), and TDS was over 500 mg/1 in all
wells. Of the 19 wells monitored, 13 are in Use Category 1, 5
in Use Category 2 and 1 is Use Category 3 under Colorado's
classification system. However, the high concentrations of
naturally occurring contaminants may preclude domestic use of
the Wasatch Formation water.
At the Old Rifle site, one or more of the monitoring wells
showed elevated levels of arsenic, lead-210, radium-226,
radium-228, sulfate, thorium-230, uranium and vanadium. Of
these, uranium was the only constituent showing a substantial
increase being 20 times background in one well. In a monitor
well 360 feet downgradient, to the southwest, the only
constituent indicating contamination was ammonium which was
only slightly above background levels. Though there is ittle
evidence of lateral movement of leachate from the pile, the
alluvial aquifer does appear to be contaminated down to its
contact with the Wasatch Formation. There are no monitor wells
into the Wasatch at or near the periphery of the Old Rifle
tailings so no samples of the confined aquifer are available in
this area. Contamination of this aquifer would probable be
minor and localized to the area immediately beneath the
tailings.
i \
The contaminant plume extends less than 800 feet >.downgradient
from the pile and probably discharges into thexColorado River
within this distance. Minimum flushing time, once the tailings
are removed is estimated to be 1.9 years. \
At the New Rifle site, both the alluvial and Wasatch aquifers
are contaminated; in each case, the area of contamination is
defined by the sulfate plume. The entire saturated thickness
(15 to 20 feet) of the alluvial aquifer is contaminated over an
area of at least 400 acres. Contaminant concentrations are
highest directly under and west of the tailings pile \and the
vanadium ponds. Some contaminated water may discharges, into the
Colorado River 3000 feet southwest of the tailings pile;
contamination can also be detected in a well 8000 feet west of
the pile. Uranium levels ranged from 3 to 44 times background,
molybdenum from 25 to 150 times background in 2 discrete
localized plumes, sulfate from about 2 to over 40 times
background, ammonium from 525 to over 16000 times background,
nitrate concentrations are inversely related to the ammonium
levels, and chloride levels were up to 11 times background
(DOE87). Three contaminants have been identified in the
Wasatch Formation aquifer: uranium (up to 200 times
background), molybdenum (up to 16 times background), and
sulfate (up to 117 times background) (DOE87). \
4-152
-------
The sulfate plume in the alluvial aquifer extends at least 7000
feet downgradient from the tailings pile and the plume in the
Wasatch extends for 3000 feet downgradient; both plumes appear
to be actively augmented by the tailings pile. Calculations
indicate that, once the tailings are removed, the plumes would
be completely dispersed or discharged to the Colorado River
within 2 miles downgradient of the tailings pile. The
estimated minimum flushing times are 45 years for the alluvial
aquifer and 3840 years for the Wasatch Formation aquifer.
4-153
-------
TABLE 4-27
Site Name: Rifle (New Site)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 1 of 2
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha
Lead
Ra-226 + Ra-228
(Radium)
Standard
(mg/1) I/
0.05
1.0
0.01
0.05
15pCi
0.05
S.OpCi
Hydraulic Flow
Relationship
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Cross-gradient
Down gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Number of
Analyses
1
24
3
13
1
24
3
13
1
24
3
13
1
24
3
13
1
24
3
13
1
24
3
13
1
24
3
13
Number of
Analyses
Exceeding
Standard
1
2
2
1
8
2
— i-
_!__
— —
";-
- —
Percent
Exceeding
Standard
4
67
8
100
34
15
Maximum
Value
Obtained
(mg/1) I/
- -
0.03
0.03
0.25
213
660
340
_- —
— —
4-154
-------
TABLE 4-27
Site Name: Rifle (New Site)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32(a)
Data Interval: 06/25/80 to 01/09/87
Page 2 of 2
Constituent
Standard
(mg/1) I/
Hydraulic Flow
Relationship
Formation of
Completion
Number of
Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Selenium 0.01 Cross-gradient Alluvium
Down gradient Alluvium
On-Site Alluvium
Down gradient Wasatch
Silver 0.05 Cross-gradient Alluvium
Down gradient Alluvium
On-Site Alluvium
Down gradient Wasatch
I/ Values a,re reported in mg/1 unless otherwise indicated.
Standard not exceeded.
1
24
3
13
1
24
3
13
29
33
23
0.16
0.041
0.2
4-155
-------
TABLE 4-28
Site Name: Rifle (Hew Site)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32{a)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 1 of 2
Constituent
Chloride
Copper
Fluoride
Iron
Manganese
Molybdenum
Nitrate 2/
Standard Hydraulic Flow
(mg/1) I/ Relationship
250 Cross-gradient
Down gradient
On-Site
Down gradient
1.0 Cross-'gradient
Down gradient
On-Site
Down gradient
1.4 Cross-gradient
Down gradient
On-Site
Down gradient
0.3 Cross-gradient
Down gradient
On-Site
Down gradient
0.05 Cross-gradient
Down gradient
On-Site
Down gradient
0.10 Cross-gradient
Down gradient
On-Site
Down gradient
10 Cross-gradient
Down gradient
On-Site
Down gradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Number of
Analyses
1
24
3
13
1
24
3
13
1
24
3
13
1
24
3
13
. 1
24
3
13
1
24
3
13
1
24
3
13
Number of
Analyses
Exceeding
Standard
___
22
3
13
_ _ _
1
3
1
2
9
3
9
1
24
3
11
1
12
3
11
13
1
6
Percent
Exceeding
Standard
92
100
100
___
~_ _
100
12
33
15
38
100
69
100
100
100
85.
100
50
100
85
54
33
46
Maximum
Value
Obtained
(mg/1) I/
1360
1400
4200
___
2.2
6.1
9
5.6
67
44.1
152
8.03
53.9
19.6
18.8
3.0
9.2
12.7
5.07
920
310
97
4-156
-------
TABLE 4-28
Site Name: Rifle (New Site)
Data Evaluation: Site Water Quality Compared to U.S, EPA Standards Not Included in 40 CFR 192.32U)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 2 of 2
Constituent
PH 3/
Sulfate
Total Solids
Uranium 4/
Zinc
Standard Hydraulic Flow
(mg/1) I/ Relationship
6.5-8.5 Cross-gradient
Down gradient
On-Site
Down gradient
250 Cross-gradient -
Down gradient
On-Site
Down gradient
500 Cross-gradient
Down gradient
On-Site
Down gradient
0.044 Cross^gradient
Down gradient
On-Site
Down gradient
5.0 Cross-gradient
Down gradient
On-Site
Formation of
Completion
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Number of
Analyses
1
24
3
13
1
24
3
13
1
20
3
13
1
24
3
13
1
24
3
Number of
Analyses
Exceeding
Standard
4
1
24
3
13
20
3
13
1
16
2
7
1
Percent
Exceeding
Standard
— -
31
100
100
100
100
100
100
100
100
67
67
54
33
Maximum
Value
Obtained
(mg/1) I/
— —
10.69
2150
29100
34000
30300
42050
69300
44000
0.428
0.9070
1.31
0.67
•
6.3
I/ Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate
at a level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are
reported as total uranium in mg/1.
Standard not exceeded.
4-157
-------
TABLE 4-29
Site Name: Rifle (Old Site)
Data Evaluation: Site Water Quality Compared to U.S.
Data Interval: 06/25/80 to 01/09/87
EPA Standards from 40 CFR 192.32(a)
Page 1 of 2
Constituent
Arsenic
Barium
Cadmium
Chromium
Gross Alpha
Lead
V
Ra-226 + Ra-228
Standard
(mg/1) I/
0.05
1.0
0.01
0.05
15pCi
0.05
S.OpCi
Hydraulic Flow
Relationship
Upgradient
Down gradient
On-Site
Upgradient
Upgradient
Down gradient
On-Site
Upgradient
Down gradient
On-Site
Upgradient
Down gradient
On-Site
Upgradient
Down gradient
On-Site •
Upgradient
Upgradient
Down gradient
On-Site
Upgradient
Upgradient
Down gradient
On-Site
Upgradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Number of
Analyses
2
3
6
2
2
3
6
2
3
6
2
3
6
2
3
6
2
2
2
6
2
2
3
6
2
Number of
Analyses
Exceeding
Standard
1
.._«
___
_ .__
2
2
6
2
2
Percent
Exceeding
Standard
17
— — _
— — _.
— _ —
___
— — _
— — —
— _ —
— — —
100
100
100
100
34
Maximum
Value
Obtained
(mg/1) I/
___
0.23
—_ -.
•
81
68
980
22
__—
104.6
Ra-226 only
4-158
-------
TABLE 4-29
Site Name: Rifle (Old Site)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards from 40 CFR 192.32U)
Data Interval: 06/25/80 to 01/09/87
Page 2 of 2
Constituent
Selenium
Standard Hydraulic Flow Formation of Number of
(mg/1) I/ Relationship Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Silver
0.01 Upgradient Alluvium
Down gradient Alluvium
On-Site Alluvium
Upgradient Wasatch
0.05 Upgradient Alluvium
Down gradient Alluvium
On-Site Alluvium
1
1
2
50
33
33
0.18
0.06
0.016
I/ Values are reported in mg/1 unless otherwise indicated.
— Standard not exceeded.
4-159
-------
TABLE 4-30
Site Name: Rifle (Old Site)
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.32(a)
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
Page 1 of 2
Constituent
Chloride
Copper
Fluoride
Iron
Manganese
Molybdenum
Nitrate 2/
PH 3/
Standard Hydraulic Flow
(mg/1) I/ Relationship
250 Upgradient
Down gradient
On-Site
Upgradient
1.0 Upgradient
Down gradient
On-Site
1.4 Upgradient
Down gradient
On-Site
0.3 Upgradient
Down gradient
"On-Site'
Upgradient
0.05 Upgradient
Down gradient
On-Site
Upgradient
0.10 Upgradient
Down gradient •
On-Site
Upgradient
44 Upgradient
Down gradient
On-Site
Upgradient
6.5-8.5 Upgradient
Down gradient
On-Site
Upgradient
Formation of
Completion
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Sasatch
Number of
Analyses
2
2
6
2
2
3
6
2
3
6
2
3
6
2
2
3
6
2
2
3
6
2
2
3
6
2
2
3
6
2
Number of
Analyses
Exceeding
Standard
— — —
— — _
2
~_ «
__ _
1
2
1
2
5
2
1
1
2
2
1
1
1
1
Percent
Exceeding
S.tandard
50
100
17
100
50
67
83
100
50
33
38
100
50
33
17
50
Maximum
Value
Obtained
(mg/1) I/
455
5700
0 44
U • *± *±
312
0 80
\J • O \J
2 49
ti • *± _7
i no
j. • u y
15.4
0 .12
0 18
\J • J. O
fi 1 9
U • -L Ł.
0.16
19.5
^7 9
J / . Ł.
1 4 fi
,lft.D
9.44
4-160
-------
TABLE 4-30
Site Name: Rifle (Old Site) .
Data Evaluation: Site Water Quality Compared to U.S. EPA Standards Not Included in 40 CFR 192.
plus Uranium and Molybdenum
Data Interval: 06/25/80 to 01/09/87
page 2 of 2
Constituent
Standard Hydraulic Flow Formation of Number of
(mg/1) I/ Relationship Completion Analyses
Number of
Analyses
Exceeding
Standard
Percent
Exceeding
Standard
Maximum
Value
Obtained
(mg/1) I/
Sulfate
Total Solids
Uranium 4/
250
500
0.044
Upgradient
Down gradient
On-Site
Upgradient
Upgradient
Down gradient
On-Site
Upgradient
Upgradient
Down' "gradient
Upgradient
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
Alluvium
Alluvium
Alluvium
Wasatch
2
1
6
2
2
2
6
2
1
1
4
100
33
100
100
100
67
100
100
50
33
67
2640
1300
814
4910
5242
2814
1750
15000
0.887
0.082
2.08
I/ 'Values are reported in mg/1 unless otherwise indicated.
2/ Concentrations of nitrate as nitrogen at a level of 10 mg/1 is equivalent to concentration of nitrate as nitrate
at a level of 44 mg/1. All analyses are reported in terms of nitrate as nitrate.
3/ pH reported in standard units.
4/ 30 pCi/1 of uranium is equivalent of 0.044 mg/1, assuming the bulk of uranium is U-238. All analyses are
reported as total uranium in mg/1.
Standard not exceeded.
4-161
-------
4.16 CURRENT USES OF CONTAMINATED GROUND WATER
Contaminated ground water is believed to be used as drinking
water at only two sites: Gunnison, Colorado, and Monument
Valley, Arizona (Le87). However, because of the remoteness of
some sites it is possible that sporatic use of contaminated
ground water can occur, especially by individuals or families.
Concentrations of hazardous constituents and other data in
ground water samples from downgradient wells at Gunnison are in
Table 4-1. These same data for upgradient wells are given in
Table 4-2 and for crossgradient wells in Table 4-3. The
locations of these wells are shown in Figures '4-1 and 4-2.
This information is from the draft environmental assessment for
the Gunnison site (DOE84).
In Table 4-1, the downgradient domestic wells are identified by
names (Hitt, Trainer, Rider, Tomichi, Collins, David, Deschene,
Coleman, Corral, Maries, and Valco). Of these domestic wells,
five of 19 samples of ground water exceeded a uranium
concentration of 30 pCi/1 (0.044mg/l) and one of 19 samples
exceeded a selenium concentration of 0.01 mg/1. For all
downgradient wells, uranium exceeded 30 pCi/1 in 25 of 59
samples and selenium exceeded 0.01 mg/1 in nine of 73 samples.
In addition, for other hazardous constituents, cadmium
concentrations exceeded 0.01 mg/1 in four of 58 samples and
nitrate concentrations exceeded 10 mg/1 in seven of 59 samples.
In Tables 4-2 and 4-3, only three samples of ground water
exceeded the drinking water standards for hazardous
constituents. These three samples contained nitrate at
concentrations of 22 to 35 mg/1 and were collected immediately
upgradient of the tailings pile.
The Gunnison ground water data indicate that uranium and sulfate
have moved from the tailings area since peak concentrations are
found downgradient from the tailings (DOE86). It is reasonable
to suspect, therefore, that concentrations pf uranium and
sulfate will increase in the downgradient domestic wells as
these contaminants move downgradient. Figure 4-3 depicts the
uranium plume near the Gunnison pile.
At the Monument Valley site there are four residences which may
be using ground water as drinking water as shown in Figure 4-4.
Ground water quality at these residences is reflected by
concentration levels in sampling wells 602, 610, 613, 621, and
622, where chromium and gross alpha exceed drinking water
4-162
-------
.-i M c
V V
00
isisssssssss:
§in*«QO'.tnog>
-------
Table 4-31 Ground-vater quality - GunnliOfi - dowifrtdltnt (Conttnted)
yell
Z03A
2038
2048
205A
2058
206A
2068
207A
207B
208
209A
209B
210A
2108
211 A
21 IB
212A
212B
Date
10/24/83
10/25/83
10/27/83
10/23/83
10/24/83
10/19/83
01/31/84
01/31/84
10/19/82
02/01/84
02/01/84
10/17/83
01/29/84
10/17/83
01/29/84
10/12/83
10/13/83
10/13/83
10/14/83
10/17/83
01/29/84
10/17/83
01/29/84
10/23/84
10/20/83
10/25/83
10/26/83
10/18/83
01/26/84
10/18/83
01/27/84
Kg
26.4
14.6
23.1
61.2
11.8
86.1
75.5
72.0
42.1
36.5
36
64.4
58.0
30.5
28.2
38.4
37.5
37.0
38.1
91.7
96.8
35.0
33.0
78.2
46.8
112
46.2
78.5
66.3
42.6
30.5
m
N/A
N/A
H/A
N/A
H/A
N/A
66.5
77.0
N/A
9.40
9.40
N/A
24.4
N/A
3.36
N/A
N/A
H/A
N/A
N/A
35.5
N/A
4.93
N/A
H/A
H/A
H/A
N/A
38.0
H/A
5.00
Ko
<0.001
X0.001
* 0.058
0.003
0.009
0.008
<0.001
<0.01
0.007
<0.001
<0.010
<0.001
<0.001
0.008
<0.001
<0.001
<0.001
<0.001
<0.001
0.003
<0.001
0.008
<0.001
0.002
0.006
<0.001
0.006
0.002
<0.001
0.007
<0.001
R03
45
50
3.5
11.0
4.8
2.3
3.1
< 1
< 0.7
2.0
< 1.0
1.0
2.4
1.1
2.6
< 0.7
1.1
1.0
< 0.7
. 1.0
2.3
< 0.7
2.1
110
2.3
45
12
1.4
2.3
<0.7
2.3
Ha
41.6
34.8
65.5
88.7
33.2
109
49.9
45
48.6
21.8
18.0
94.4
47.5
43.9
16.6
53.4
53.2
50.1
54.2
96.5
100
44.2
19.3
183
45.1
128
58.0
92.0
54.3
46.6
25.3
81
<0.001
<0.001
0.002
0.061
0.019
0.015
<0.04
<0.04
0.045
<0.04
0.14
0.002
<0.04
0.068
<0.04
0.13
0.13
0.20
0.18
0.002
<0.04
0.049
<0.04
<0.001
0.051
<0.001
0.018
<0.001
<0.004
0.020
<0.004
P
N/A
N/A
N/A
N/A
N/A
N/A
< 5
N/A
H/A
< 5
H/A
H/A
< 5
H/A
< 5
H/A
H/A
H/A
N/A
H/A
< 5
H/A
< 5
H/A
H/A
H/A
H/A
H/A
< 5
H/A
< 5
Pb
0.009
<0.001
<0.001
<0.001
<0.001
<0.001
<0.00i
0.010
0.001
<0.001
<0.010
0.002
<0.001
<0.001
-------
I
H-*
<_n
<-»ot/>t/» x « Z c-i c-> o en ^ so —i ai roroiN> c
«/>«/>-o-o — 01 » o o n o> o o—•»— *-*-*- n
^^ ^^ I i ^^ ^^ ^ * ^^
-------
Tibia 4-31 Ground-water quality - Gunnison - doxngradlint (Conttntad)
Well
213A
2138
214B
Hitt
Trainer
Rider
Tmichi
Collins
David
Deschene
Colemn
Corral
Narks
Valco
Hi list te
SP-1
SP-3
CSU-213
CSU-214
Date
10/18/83
10/18/83
10/26/83
02/02/84
02/07/84
02/27/84
01/30/84
01/30/84
09/16/83
09/16/83
11/01/82
10/11/82
09/16/83
10/11/82
09/15/83
02/07/84
09/16/83
10/07/83
02/01/84
02/01/84
10/11/82
09/16/83
11/01/82
09/16/83
10/12/82
11/01/82
11/01/82
11/01/82
Kg
61.2
28.2
18.3
20.1
27.5
6.48
20.4
20
3.1
9.50
10.0
<1
15.6
16
22.2
14.4
15.3
21.9
22.2
19
18
19.6
17
16.8
16
16
43
11
Hn
H/A
N/A
N/A
2.05
0.06
0.03
0.08
0.07
N/A
N/A
N/A
H/A
H/A
N/A
N/A
0.43
N/A
N/A
0.24
0.18
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Mo
O.Q04
<0.001
0.007
<0.001
<0.001
<0.001
<0.001
<0.01
<0.00l
<0.001
<0.05
<0.05
<0.001
<0.05
<0.001
<0.001
<0.001
<0.001
<0.001
<0.01
<0.05
<0.001
<0.05
<0.001
<0.05
<0.05
<0.05
<0.05
•s
<0.7
1.0
2.3
2.7
<0.7
<0.7
2.5
<1
<0.7
<0.7
<5
<5
1.5
<5
1.3
1.8
1.3
1.1
2.4
<1
<5
1.7
<5
1.3
<5
<5
115
<5
Ha
75.7
36.0
38.7
13.9
8.13
3.81
10.1
6.5
94.1
25.1
9.0
122
20.5
10
23.4
4.88
17.2
12.9
12.0
6.6
10
19.5
7
16.9
7
11
22
4
Hi
<0.001
<0.001
0.008
<0.004
<0.04
<0.04
<0.04
<0.04
0.053
0.053
H/A
H/A
0.052
N/A
0.072
<0.04
0.042
0.06
<0.04
<0.04
H/A
0.070
N/A
0.064
N/A
N/A
N/A
N/A
P
N/A
N/A
N/A
< 5
< 5
< 5
< 5
N/A
N/A
N/A
N/A
N/A
" N/A
N/A
N/A
< 5
N/A
< 5
< 5
N/A
N/A
N/A
N/A
N/A
N/A
H/A
H/A
N/A
Pb
0.007
<0.001
<0.001
<0.001
<0.001
<0.001
<0.0012
<0.010
<0.001
<0.001
<0.010
<0.010
<0.001
<0.010
<0.001
<0.001
<0.00l
<0.001
<0.001
<0.010
<0.010
-------
41
i
•11
UJ O*"
u
^ *^ ^ "
cw in in «*• •• *• «*
oo oaooco oa a eo aoeo co ea oo 09 0003 GO eeeo eo
^
S
5
i
I
-------
Table 4-31 Ground-water quality • fiunnison - doungradient (Continued)
HeU
SP-1
SP-2
SP-3
GUH-209
GUN-212A
GUN -213
GUN-214
Date
08/31/82
05/30/82
11/00/81
08/31/82
06/30/82
11/00/81
08/31/82
06/30/82
11/00/81
08/31/82
06/30/82
11/00/81
08/31/82
06/30/82
08/31/82
06/30/82
11/00/81
08/31/82
06/30/82
*J
16
17
17
82
60
36
21
22
28
47
40
52
46
48
39
44
50
12
12
Hn
0.4
0.03
N/A
8.63
6.20
N/A
.25
0.05
N/A
.43
0.74
N/A
8.79
9.30
8.16
5.20
N/A
0.03
0.11
Ho
N/A
H/A
H/A .
H/A
H/A
H/A
N/A
N/A
H/A
N/A
H/A
N/A
N/A
N/A
N/A
N/A
H/A
H/A
H/A
*o3
H/A
H/A
H/A
H/A
H/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Ha
.6
6
6
32
17
9
9
22
10
22
22
39
31
34
4
24
26
4
5
Hi
N/A
H/A
N/A
N/A
N/A
N/A
N/A
H/A
N/A
N/A
H/A
H/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
P
N/A
H/A
N/A
N/A
N/A
N/A
N/A
H/A
N/A
H/A
H/A
H/A
N/A
N/A
N/A
N/A
H/A
R/A
N/A
Pb
H/A
H/A
H/A
H/A
H/A
H/A
N/A
N/A
N/A
H/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
so4 s<
14 <0.
34 ?0.
77 ~H/
780 0.
757 0.
1150 H
140 <0.
125 ?0.
562 ~H
460 <0.
422 "0.
1150 N
560 0.
560 0.
480 0.
571 <0.
1440 ~N
16 <0.
43 ?0.
i Si
1 N/A
I N/A
rA N/A
N/A
N/A
A N/A
H/A
H/A
A N/A
fi/A
H/A
A N/A
N/A
N/A
N/A
N/A
A N/A
N/A
N/A
U
N/A
H/A
N/A
N/A
N/A
H/A
H/A
H/A
H/A
N/A
N/A
H/A
N/A
H/A
H/A
H/A
N/A
N/A
N/A
V
N/A
H/ft
N/A
N/A
N/A
H/A
H/A
H/A
N/A
N/A
N/A
H/A
H/A
H/A
H/A
H/A
H/A
H/A
H/A
Zn
H/A
H/A
H/A
N/A
H/A
H/A
H/A
H/A
H/A
B/A
H/A
H/A
H/A
H/A
N/A
H/A
N/A
N/A
N/A
Pb-210
(PCI/1)
N/A
H/A
N/A
N/A
H/A
N/A
N/A
N/A
H/A
H/A
H/A
N/A
H/A
N/A
N/A
H/A
H/A
H/A
N/A
[I/A - Not Available
4-168
-------
Table 4-31 Ground-water quality - Gunnison - downgradient (Continued)
Well
203A
203B
204B
205A
205B
206A
206B
207A
207B
208
209A
209B
210A
210B
21 1A
21 IB
212A
212B
Date
10/24/83
10/25/83
10/27/83
10/23/83
10/24/83
10/19/83
01/31/84
01/31/84
10/19/82
02/01/84
02/01/84
10/17/83
01/29/84
10/17/83
01/29/84
10/12/83
10/13/83
10/13/83
10/14/83
10/17/83
01/29/84
10/17/83
01/29/84
10/23/84
10/20/83
10/25/83
10/26/83
10/18/83
01/26/84
10/18/83
01/27/84
Ra-226
(pCi/1)
0.0 + 0.6
0.0 + 0.2
0.9 + 0.6
0.4 + 0.4
0.1 + 0.2
0.7 + 1.0
0.0 + 0.2
0.1 + 0.3 "
0.1 + 0.2
< 1.0
0.1 + 0.1
0.0 + 0.2
0.1 + 0.2
0.1 + 0.2
0.0 + 0.2
0.0 + 0.2
0.0 + 0.2
0.1 + 0.2
0.2 + 0.2
0.0 + 0.2
0.4 + 0.3
0.0 + 0.2
0.0 + 0.6
0.0 + 0.3
0.0 + 0.2
0.4 + 0.5
0.1 + 0.1
0.0 + 0.2
0.2 + 0.2
0.0 + 0.2
Th-230
(pCi/1)
0.0 + 1.9
0.6 + 0.7
8.6 + 2.6
1.2 + L8
0.0 + 0.8
0.4 +* 1.4
"V 9 T • A 0 Tf
0.0 + 0.4
2.8 + 2.4
0.6 + 0.7
2.7 + 2.2
0.4 + 0.6
0.8 + 1.6
0.6 + 0.7
0.0 + 0.5
0.0 + 0.5
0.0 + 0.5
0.0 + 0.5
0.4 + 1.4
0.7 + 0.9
3.6 + 2.6
0.0 + 0.4
2.0 +2.1
3.2 + 2.5
0.4 + 0.6
0.6 + 2.0
0.4 + 1.4
0.4 + 0.6
1.2+1.8
0.3 + 0.6
TOS
624
347
2280
1340
256
m&n
97nA
979(rt
2S50
C>wvU
1420
1410
2420
2440
1720
1690
1700
1730
1870
2570
2120
2400
2760
b » W
2610
3160
•*» yf*f
2250
1940
1900
1720
2270
4-169
-------
Table 4-31 Ground-water quality - GtwnlsM - dwngradtent (Concluded)
Hell
213A
2138
2148
Hitt
Trainer
•Rider
Ton 1 chi
Collins
David
Deschene
Coleman
Corral
Marks
Valco
Mill site
SP-1
SP-3
CSU-213
CSU-214
Date
10/18/83
10/18/83
10/26/83
02/02/84
02/07/84
02/27/84
01/30/84
01/30/84
09/16/83
09/16/83
11/01/82
10/11/82
09/16/83
10/11/82
09/15/83
02/07/84
09/16/83
10/07/83
02/01/84
02/01/84
10/11/82
09/16/83
11/01/82
09/16/83
10/12/82
11/01/82
11/01/82
11/01/82
Ra-226
(pCl/1)
0.2 + 0.2
0.2 7 0.2
0.2 + 0.2
0.0 + 0.2
0.0 7 0.2
0.0 7 0.2
0.0 7 0.2
0.1
0.2
0.2
0.3
< 2
0.5 + 0.4
<~2
0.0 + 0.2
0.2 + 0.3
0.1 + 0.2
0.3 + 0.3
0.0 + 0.2
71
< 2
+ 0.2
?2
+ 0.2
72
< 2
< 2
< Z
0.0
0.0
Th-230
(pCt/1)
0.4 + 1.4
0.0 7 1.5
1.2 + 2.3
0.0 + 0.4
0.0 + 0.4
0.0 + 0.4
0.1 + 0.5
0.2 + 6.7
0.8 7 1.0
N7A
N/A
0.8 + 1.0
N/A
0.8 + 0.9
0.070.4
1.2 7 1.0
0.9 7 1.1
0.2 + 0.5
N/A*
1.0 + 0.9
N/A
0.7 + 0.8
N/A
N/A
N/A
SI/A
IDS
994
2670
459
370
556
119
401
N/A
277
372
N/A
H/A
302
N/A
481
304
288
500
450
400
N/A
351
N/A
296
N/A
N/A
N/A
N/A
measurements as mg>
N/A • Not analyzed.
4-170
-------
Table 4-32 Ground-water quality - Gunntson - upgradlmt
Well
201A
2018
202A
2028
Weaver
Cooper
Brat ton
City
City 19
Woods
Singer
Electrical
conductivity Teay.
Date tMho/oi) (»C)
10/23/83
10/21/83
10/19/83
10/21/83
02/07/84
02/06/84
07/27/84
11/01/82
09/15/83
02/27/84
11/01/82
09/16/83
11/01/82
09/16/83
330
380
350
375
N/A
N/A
N/A
315
355
N/A
280
310
330
350
12
14.5
11.5
14
8.3
7.5
7.0
12
12.0
6.9
15
14.8
14
12
PH
7.57
7.11
7.0
7.1
7.45
7.2
7.4
7.55
6.5
7.4
7.26
6.68
7.86
6.62
Alkalinity
(as CaC03) Al As Ba Ca cd
216
254
240
245
215
130
300
N/A
240
220
N/A
200
N/A
290
<0.002 <0.001 0.021 58.0 <0.0005
<0.003 <0.001 0.028 69.5 0.005
<0.003 <0.001 0.070 85.0 0.008
<0.003 <0.001 0.120 84.9 0.006
0.003 <0.001 0.005 59.8 <0.0001
0.005 <0.001 0.005 35.3 <0.0001
0.006 <0.001 0.002 70.3 <0.0001
<0.10 <0.010 N/A 76 <0.005
0.147 <0.001 0.270 70.8 <0.001
0.002 <0.001 0.002 64.3 <0.0001
<0.10 <0.010 N/A 55 N/A
0.143 <0.001 0.233 61.0 < 0.001
<0.10 <0.010 0.18 70 N/A
0.150 <0.001 0.27S 76.3 <0.001
™" ' •'•' i • i. ..
Cl Cr
8.0 <0.001
9.4 0.003
12 <0.001
11 <0.001
7.8 <0.001
14 <0.001
12.6 <0.001
2 <0.010
3.0 <0.001
5.5 <0.001
2 N/A
4.8 <0.001
1 N/A
5.0 <0.001
Cu F
0.006 <0.1
<0.001 <0.1
<0.001 <0.1
<0.001 <0.1
<0.001 <0.1
<0.001 <0.1
<0.001 <0.1
0.013 <1
<0.001 N/A
<0.001 <0.1
N/A <1
0.046 N/A
N/A <1
<0.001 N/A
Fe
0.011
0.02
0.27
2.80
0.17
0.38
0.05
0.6
0.263
0.11
2.7
0.254
3.3
0.277
Hg
N/A
N/A
N/A
N/A
N/A
N/A
N/A
<0.002
N/A
N/A
N/A
N/A
N/A
N/A
K
5.25
3.69
1.85
3.38
1.30
2.38
14.0'
4
5.05
1.38
3
7.33
1
7.25
[N/A - Mot Analyzed
4-171
-------
Table 4-32 Ground-water quality - SanaUoa - upgradleat (CMtlftwd)
Well
201A
201B
202A
202B
Heaver
Cooper
Brattoi!
City
City 19
Moods
Singer
Date
10/23/83
10/21/83
10/19/83
10/21/83
02/07/84
02/06/84
07/27/84
11/01/82
09/15/83
02/27/84
11/01/82
09/16/83
11/01/82
09/16/83
Hg
12.5
13.9
16.8
15.8
13.8
10.3
26.3
14
14.1
13.0
12
14.3
14
15.0
Hn
N/A
H/A
N/A
N/A
N/A
0.23
0.02
H/A
H/A
0.03
N/A
N/A
N/A
N/A
Ho
0.004
<0.001
0.003
0.003
<0.001
<0.001
<0.001
<0.05
<0.001
<0.001
<0.05
<0.001
<0.05
<0.001
N03
35
25
22
3.1
2.0
1.9
1.7
< 5
1.1
< 0.7
< 5
< 0.7
< 5
1.5
Na
39.4
9.22
6.87
7.49
6.78
14.9
19.3
6
15.8
3.83
6
18.1
5
16.2
HI
0.003
<0.001
<0.001
<0.001
<0.04
<0.04
<0.04
N/A
0.071
<0.04
N/A
0.037
N/A
0.043
P
N/A
N/A
N/A
H/A
< 5
< 5
< 5
N/A
N/A
< 5
H/A
N/A
N/A
N/A
Pfa
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.010
<0.001
<0.001
N/A
<0.001
N/A
0.012
so4
24.7
49.5
31.2
28.1
9.9
16.1
36.2
IS
43.8
16.5
11
11.4
15
19.5
••IMMMH^MMH
Se
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.010
<0.002
<0.002
<0.010
<0.002
<0.010
<0.002
SI
5.6
5.1
0.5
5.7
0.6
1.6
5.7
3.2
N/A
1.2
H/A
B/A
H/A
N/A
U
0.0062
0.0038
0.0018
0.0063
0.0020
0.0032
0.0085
0.003
0.0023
0.0021
0.003
0.0078
0.003
0.0039
V
<0.004
<0.004
<0.004
<0.004
<0.004
<0.004
<0.004
<0.05
<0.004
<0.004
<0.05
-------
Table 4-32 Ground-water quality - Gunnlson - upgradlent (Concluded)
Well
^•••••••••••wiw^a^
201A
201B
202A
202B
Weaver
Cooper
Bratton
City
City 19
Woods
Singer
Date
10/23/83
10/21/83
10/19/83
10/21/83
02/07/84
02/06/84
07/27/84
11/01/82
09/15/83
02/27/84
11/01/82
09/16/83
11/01/82
09/16/83
Ra-226
(pCi/1)
0.0 + 0.2
0.4 4- 0.4
0.1 + 0.2
0.0 + 0.3
0.0 + 0.2
0.0 + 0.2
0.0 + 0.2
< 2
0.8 + 0.5
0.0 + 0.2
< 2
0.4 + 0.4
< 2
0.3 + 0.3
Th-230
(PCI/1)
0.0 + 0.8
2.4 + 2.2
0.0 + 1.4
0.8 + 1.6
0.1 + 0.5
0.0 + 0.9
0.0 + 0.4
N/A
0.1 + 0.7
0.0 i 0.5
N/A
0.0 + 0.6
N/A
0.5 + 0.8
TOS
291
381
345
359
262
199
401
N/A
262
246
N/A
196
N/A
282
N/A » Not analyzed.
4-173
-------
Table 4-33 Ground-water quality - taiilso* - crositradiiflt
Electrical
conductivity leap. Eh
Well Date (w*o/«) CO MO
Tuttle 11/01/82 180
10/26/83 162
Reid 11/01/82 180
Hatcher 10/06/83 160
Sjoberg 10/06/83 155
02/08/84 N/A
Wallace 10/06/83 290
02/08/84 N/A
13.5 N/A
13 162
11 N/A
10 N/A
10 N/A
7.2 N/A
10 N/A
6.0 N/A
pH
7.68
7.03
7.60
6.8
6.81
7.17
7.05
7.0
Alkalinity
(as CaC03) Al As
68
118
N/A
145
115
100
230
205
Ba
<0.10 <0.010 N/A
0.007 <0.001 0.036
<0.10 <0.010 N/A
<0.01 <0.001 0.024
<0.01 <0.001 0.017
0.001 <0.001 0.008
<0.01 <0.001 0.150
0.002 <0.001 0.009
Ca Cd Cl Cr Cu
F
< 1 N/A 1 N/A N/A <1
24.0 <0.0005 3.8 <0.001 0.006 <0.1
36 N/A 1 H/A N/A <1
33.5<0.001 1.6 <0.001 <0.02 <0.1
32.3 <0.001 1.6 <0.001 <0.002 <0.1
31.8 <0.0001 5.9 <0.00i <0.001 <0.1
62.5 <0.001 8.2 <0.001 <0.02 <0.1
62.7 <0.0001 7.5 <0.001 <0.001 <0.1
Ft
0.1
0.652
0.9
0.41
0.57
0.77
9.66
2.03
Hg K
N/A < 1
N/A 2.75
N/A 1
N/A 3.45
N/A 2.73
N/A 1.14
N/A 5.90
N/A 2.63
Well Date Hg
Tuttle 11/01/82 <1
10/26/83 6.33
Reid 11/01/82 8
Hatcher 10/06/83 7.30
Sjoberg 10/06/83 6.20
02/08/84 6.68
Wallace 10/06/83 13.6
02/08/84 13.4
Hn
N/A
N/A
N/A
N/A
N/A
1.02
N/A
4.16
Ho
<0.05
0.003
<0.05
<0.001
<0.001
<0.001
<0.001
<0.001
N03
. , •...• 1 1 i •
<5
6.1
<5
1.0
1.2
<0.7
1.1
<0.7
Na
55
N/A
55
12.3
11.9
4.60
17.8
6.21
,«^^— — — •
HI
N/A
0.003
N/A
0.09
0.12
<0.04
0.15
<0.04
.^^ «—«i.»^— •
P
N/A
N/A
N/A
< 5
< 5
< 5
< S
< 5
Pb
N/A
<0.001
N/A
<0.001
<0.001
<0.001
<0.00l
<0.001
S04 S0
7 <0.010
21.4 <0.002
7 <0.010
<1 <0.01
<1 <0.01
14.8 <0.002
<1 <0.01
21.4 <0.002
Si
N/A
1.0
N/A
4.8
1.4
3.8
1.8
2.6
U
<0.001
0.0006
<0.001
0.0018
0.0009
0.0011
0.0025
<0.0029
V
<0.05
<0.004
<0.05
<0.004
<0.004
<0.004
<0.004
<0.004
Zn
N/A
0.013
N/A
0.024
0.053
0.010
0.014
0.022
Pt>-210
(pCi/1)
N/A
0.2 * 1.3
H/A
0.0 + 0.9
0.0 + 0.8
0.8 * 0.7
0.0 * 0.9
0.9 + 0.9
[a/A - Not Analyzed]
4-174
-------
Table 4-33
Ground-water quality - Gunnlson - crossgradlent (Concluded)
Well
Tuttle
Reid
Hatcher
Sjoberg
Wallace
Date
11/01/82
10/26/83
11/01/82
10/06/83
10/06/83
02/08/84
10/06/83
02/08/84
Po-210
(pCi/1)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Ra-226
(pCi/1)
< 2
0.3 + 0.3
0.3 + 0.3
0.0 + 0.2
0.1 + 0.2
0.5 + 0.3
0.4 + 0.3
Ra-228
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Th-230
(PCI/1)
N/A
2.5 + 1.4
NjA
0.2 + 0.9
0.4 + 0.6
0.2 + 0.9
0.8+1.1
0.0 + 0.4
IDS
N/A
72.0
N/A
117
112
190
281
246
••• — —
N/A = Not analyzed.
4-175
-------
•wain* TA,LINQ8 PILE
• CITY *8
DIRECTION OF
GROUND WATER
FLOW
DE8CHENE* «MILL SITE
•COLEMAN
,OSBORN
• TRAINER
RIDER*
•MARKS
•LIGHT
TOMICHI
• COLLINS
•HITT
PIQURE 4-1
APPROXIMATE LOCATION OF DOMESTIC WELLS SAMPLED AT QUNNISON
4-176
-------
DKECTtON OF
GROUND WATER
FLOW
8EWAQE TREATMENT
PLANT
FIGURE 4-2
LOCATIONS OF MONITOR WELLS
(GUNNISON)
MOST WELLS INSTALLED AS PAIRS »10 FT APART
DEPTH OP 'A' WIL1S«4» ft. -f WELLS»10 FT.
4-177
-------
TOf Or BXHTIHO
TMUHQt Pill
QCSIQNATfO
•IT! tOUNDANV
0 MO
ai
SCALE IN FEET
-10X = I80PLETH
FIGURE 4-3
URANIUM PLUME NEAR PILE (GUNNISON)
U AS MULTIPLE OF HIGHEST BACKGROUND CONCENTRATION (0.008 mfl/l)
DATA: 83 SAMPLES FROM 48 WELLS
4-178
-------
standards at 622 and 610, respectively, as shown in Table 4-4.
Also, the sulfate concentration is elevated at well 622.
Background water quality is shown in Table 4-5 for the alluvial
aquifer at Monument Valley and in Table 4-6 for the Shinarump
and DeChelly Sandstone aquifers. Figure 4-5 illustrates the
sulphate plume at Monument Valley; Figure 4-6, the nitrate
plume; and Figure 4-7, the uranium plume. The locations of the
four residences are shown in each figure.
4.17 ORGANIC CONTAMINANTS IN GROUND WATER
Few data are available regarding organic contaminants in ground
water. The NRC is conducting a program of sampling liquids in
uranium mill tailings impoundments. This program is to
establish a data base for hazardous constituents (40 CFR 261
Appendix VIII) in the tailings (Sm87).
The laboratory analyses performed on these tailings water
samples indicate positively if any of 150 constituents are
present in the tailings solution. These constituents include 54
general chemistry (anions, cations, metals) 12 volatile organic
groups, 81 semivolatile groups, and three radionuclides. None
of the organics have been found in the tailings solutions that
were tested from nine tailings impoundments by the NRC. The
elemental forms of 15 hazardous constituents were identified
These organic groups and the 15 hazardous constituents that
tested postive are listed in Table 4-7.
In uranium milling, uranium has been recovered from leach
liquors by three methods: solvent extraction, ion exchange, and
precipitation. The solvent extraction method was used to
produce 43% of total uranium production in 1976 and a solvent
extraction/ion exchange combination was used to produce 18% the
same year (NUREG80). Two processes, the Dapex and the Amex, are
extensively used. The Dapex process uses -a 4% solution of
di(2-ethylhexyl) phosphoric acid (EHPA) in kerosene with
tributyl phosphate added as a modifier. The Amex process uses a
6% solution of tertiary amine, such as alinine-336, in kerosene
with isodecanol added as a modifier.
Early work in solvent extraction was reviewed by Flagg (F161)
In the early 1940's, diethyl ether was used to purify uranium'in
the first large scale application of solvent extraction in
nydrometallurgy. Flagg groups the organic extractants into
organophosphorous compounds, as used in the Dapex process, and
4-179
-------
N
620
TO HALCHITA AND
MEXICAN HAT
\
INDIAN SERVICE
ROUTE 6440
612.
• TO MONUMENT
NO. 2 MINE
LEGEND
c 661
RESIDENCE
DOE MONITOR WELL
EPHEMERAL DRAINAGE
• 6S2
FEET
FIGURE 4-4
DOE MONITOR WELL LOCATIONS,
MONUMENT VALLEY SITE
4-180 .
-------
Table 4-34 Exceedence of water-quality standards
at Monument Valley
Arsenic
Barium
Cadmium
Chloride
Chromium
Copper
Gross alphab»c
Iron
"lead
Manganese
Mercury
Nitrate (as N)
pHd
Ra-226 + 228°
Selenium
Silver
Sulfate
EPA primary EPA secondary
standard3 standard3
0.05
1.0
0.01
250.0
0.05
1.0
15
0.3
0.05
0.05
0.002
10.0
6.5-8.5
5.0
0.01
0.05
250.0
Exceeded at
none
none
none
none
614, 622
none
606, 610, 614,
657, 662, 620.
614, 610
none
603. 605. 606, 610,
620. 621, 622. 650,
651, 654, 659, 660,
655, 662, 657. 664
none
606, 655. 656
620. 622. 650, 660,
663, 668, 661
none
none
none
605, 606, 622, 653.
655, 656, 662, 669
Total dissolved
solids
Uranium6
Z1nc
0.015
500.0
5.0
605. 606. 614, 617,
620, 622, 657
606. 614. 620, 655.
657, 662
none
aM11Hgrams per liter (mg/1) unless otherwise noted.
"P1cocur1es per liter.
cReported values of gross alpha may be erroneous at TDS levels above
500 mg/1.
^Standard units.
eHealth advisory level (Cothern et al., 1983).
4-181
-------
Table 4-35 Background water quality 1n alluvial aquifer, Monument
Valley site ;
Constituent
Observed
concentration No. of
range3 analyses
Mean3
Two Background
standard concentration
deviations3 range3
Alkalinity3
Aluminum
Ammonium
Antimony
Arsenic
Barium
Boron
Bromide
Cadmium
Calcium
Chloride
Chromium
Cobalt
Copper
Cyanide
Fluoride
Gross alphab
Gross betab
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Nitrate
Nitrite
Nitrate & Nitrite
(as N)
Total organic
carbon
Lead-210b
pH
Phosphate
Polon1um-2lOb
Potassium
Rad1um-226b
Rad1um-228b
Selenium
Silica
Silver
Sodium
196-293
0.2-0.8
<0.1-0.52
<0. 003-0. 004
<0.01
<0.1-0.3
0.2-0.8
-------
Table 4-35 Background water quality 1n alluvial aquifer. Monument
Valley site (Concluded)
Constituent
Strontium
Sulfate
SulHde
Thor1um-230b
Tin
Total dissolved
solids
Uranium
Vanadium
Z1nc
Observed
concentration No. of
range3 analyses Mean3
<0.10
55.8-158.0
<0.10
0.0-6.3(+0.7)
<0.005
294.0-626.0
<0. 003-0. 0054
<0. 01-0. 70
<0. 005-1. 6
6
6
6
6
6
6
6
6
6
<0.10
113.0
<0.10
1.2
<0.005
454.5
0.0034
0.30
0.5
Two Background
standard concentration
deviations3 range3
0.0
90.5
0.05
5.03,
0.0
253.2
0.0024
0.66
1.4
<0.10
22.5-203.5
<0.10
<1.0-6.2
^0.005
201.3-707.7
<0. 003-0. 0059
<0. 01 -0.97
<0. 005-1 .8
3In mg/1 unless otherwise noted.
bFor radlonuclldes, observed range plus analytical
background range, 1n plcocurles per liter.
error 1s shown as the
4-183
-------
Table 4-36 Background water quality, Shlnarump and OeChelly Sandstone
aquifers at Monument Valley
Constituent
Alkalinity (as CaC03)
Aluminum
Ammonium
Antimony
Arsenic
Barium
Boron
Bromide
Cadmium
Calcium
Chloride
Chromium
Cobalt
Conductance"
Copper
Cyanide
Fluoride
Gross alpha0
Gross betac
Iron
1 earl
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Nitrate
Nitrite
Nitrate & NUrlte (as N)
Organic carbon
Lead-21QC
pHd
Phosphate (as P)
Polon1um-210c
Potassium
Rad1um-226c
Rad1um-228c
Selenium
Silica
Silver
Sodium
Strontium
Sulfate
Concentration
1n Shlnarumpa
202-220
0.20-0.80
<0. 10-0. 26
<0. 003-0. 005
<0.01
<0. 10-0. 20
0.10-0.50
<0.01
<0.001
3.0-29.2
7.0-15.0
<0. 01-0. 02
<0.05
400-700
<0.02
<0.01
0.20-0.80
0.50-22.0
3.2-12.0
<0. 03-0. 33
<0.01
15.1-20.3
<0. 01 -0.10
<0.0002
<0. 01-0. 22
<0. 04-0. 11
0.5-13.29
<0. 10-1. 65
0.3-3.3
42.0-51.0
0.1-3.7
7.1-8.4
<0. 10-0. 60
0.00-0.60
1.41-3.99
0.10-8.6
0.00-0.50
0.005
9.0-13.0
<0.01
73.7-94.9
<0.10
72.0-128.0
Concentration
1n DeChelly3
97-198
0.30-0.80
<0 . 1 0
<0. 003-0. 004
<0.01
<0. 10-0. 20
0.10-0.90
<0.01
<0.001
6.34-31.7
5.0-10.0
<0. 01-0. 04
<0. 05-0. 06
210-550
<0.02
<0.01
0.20-0.60
1.0-6.10
4.4-8.0
<0. 03-0. 10
<0.01
17.0-28.0
<0. 01 -0.05
O.0002
<0. 01-0. 10
<0. 04-0. 11
1.0-22.0
<0. 10-1. 615
1.3-2.5
22. 0-53. 0
0.0-1.2
7.4-9.4
<0. 10-0. 30
0.00-0.40
1.55-5.25
0.00-0.30
0.00-0.60
<0.005
5.0-11.0
<0.01
6.4-50.2
<0.10
13.2-62.1
4-184
-------
Table 4-36 Background water quality, Shlnarump and DeChelly Sandstone
aquifers (Concluded)
Constituent
Concentration
1n Shlnarump3
Concentration
1n DeChellya
Sulflde
Temperature °C
Thor1um-230C
Tin
Total dissolved solids
Total organic halogens
Uranium
Vanadium
Z1nc
<0.10
13.0-20.0
0.00-0.20
<0.005
348.0-418.0
<0.003-0.007
0.002-0.008
<0.01-0.60
<0.005-0.09
<0.10
15.0-19.0
0.00-0.40
<0.005
158.0-321.0
<0.003
0.001-0.008
<0.01-0.80
<0.010-1.26
aAs mg/1 unless otherwise noted.
"umhos/cm2.
cP1cocur1es per liter.
dStandard units.
4-185
-------
N
I
TO HA'.CHITA AND
MEXICAN HAT
INDIAN SERVICE
ROUTE 6440
•TO MONUMENT
NO. 2 MINE
LEGEND
• RESIDENCE
• DOE ALLUVIAL MONITOR WELL
-VSULFATE ISOPLETH «mg/l)
fc° daihtd whtrt estimated
• 57
EVAPORATION
POND
APPROXIMATE SCAi-Ei IN FEET
FIGURE 4-5 SULFATE PLUME, MONUMENT VALLEY SITE
4-186
-------
n
I
INDIAN SERVICE
ROjTE 6440
•TO MONUMENT
NO. 2 MINE
LEGEND
• RESIDENCE
• DOE ALLUVIAL MONITOR WELL
^f NITRATE ISOPLETH (mg/l as N)
(dashed wh»r» tstimattd)
* EPA DRINKING WATER LIMIT
5 00 0 500 1500
APPROXIMATE SCAuE IN FEET
FIGURE 4-6
NITRATE PLUME, MONUMENT VALLEY SITE
4-187
-------
N
I
•
•
TO HALCHiTA AND
MEXICAN HAT
INDIAN SERVICE
ROUTE 6440
"TO MONUMENT
NO. 2 MINE
LEGEND
RESIDENCE
DOE ALLUVIAL MONITOR WELL
URANIUM ISOPLETH (tng/l)
' wh«r« •ttim«t«d)
.005
FIGURE 4-7 URANIUM PLUME, MONUMET VALLEY SITE
4-188
-------
Table 4-37 Sampling for Hazardous Constituents
in Uranium Mill Tailings Liquids^3)
Volatile Organic Compounds Not Found '.in- Tailings Liquids
Bromoform
Carbon tetrachloride
Chlorobenzene
Chlorodibromomethane
Chloroform
Dichlorobromomethane
1,2 - dichloroethane
1,1,2,2 - tetrachloroethane
Tetrachloroethylene
1,1,1 - trichloroethane
1,1,2 - trichloroethane
Trichloroethylene,
Semivolatile Organic Compounds Not Found in Tailings Liquids
2-Chlorophenol
2,4-Dichlorophenol
2,4-Dimethylphenol
4,6 - Dinitro-0-Cresol
2,4-Dinotrophenol
2-Nitrophenol
4-Nitrophenol
P-Chloro-M-Cresol
Pentachlorophenol
Phenol
2,4,6-Trichlorophenol
Acenaphthene
Acenaphtylene
Anthracene
Acenaphtylene
Anthracene
Benzidi.ne
Benzo(a)anthracene
Benzo(a)pyrene
3,4-Benzofluoranthene
Benzo(ghi)Perylene
Benzo(k)fluoranthene
Bis(2-Chloroethoxy) Methane
Bis(2-Chloroisopropyl Ether
Bi.s( 2-Chloroisopropyl) Ether
Bis(2-Ethylhexyl) Phthalate
4-Bromophenyl Phenyl
Butyl Benzyl Phthalate
2-Chloronaphthalene
4-Chlorophenyl Phenyl Ether
Chrysene
Dibenzo(a,h)Anthracene
1,2-Dichlorobenzene
1,3-Dichlorobenzene
Fluoranthene
Fluorene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclo-pentadiene
Hexachloroethane
Indeno (1,2,3-cd)pyrene
Isophorene
Naphthalene
Nitrobenzene
N-Nitrosodimethylamine
N-Nitrosodi-N-Propylamine
N-Nitrosodiphenylamine
Phenantrhene
Pyrene
1,2,4-Trichlorobenzene
Aldrin
Alpha-BHC
Beta-BHC
Gamma-BHC
Delta-BHC
Chlbrdane
4,4-DDT
4,4-DDE
4,4-DDD
Dieldrin
Alpha-Endosulfan
Beta-Endosulfan
Endosulfan Sulfate
Endrin
Endrin Aldehyde
Heptachlor
Heptachlor Epoxide
PCB-1242
4-189
-------
Table 4-37 (continued)
I/4-Dichlorobenzene
3,3'-Dichlorobenzidine
Diethyl Phthalate
Dimethyl Phthalate
Di-N-Butyl Phthalate
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Di-N-Octyl Phthalate
1,2-Diphenylydrazine
(as Azobenzene)
PCB-1254
PCB-1221
PCB-1232
PCB 1248
PCB-1260
PCB-1016
Toxaphene
Hazardous Constituents Found in Tailings Liquids
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cyanide
Fluorine
Lead
Mercury
Molybdenum
Nickel^
Radium 226 and
Selenium
Thorium
Uranium
228
(a) from TSM87)
4-190
-------
organonitrogen compounds, amines, as used in the Amex process.
Flagg also reports that there was "very extensive research" in
the development of several organic extractants for recovering
uranium from sulfuric acid leach liquors. Thus, it appears
reasonable to assume that several organic compounds were used at
uranium mills, probably in the 1940's and 1950's.
Total organic carbon and total organic halogen concentrations
were reported by DOE in ground water near several of the
inactive sites, including .some EPA priority pollutants (for
example, see DOE-86a). While it appears this contamination is
not from the tailings (the residual radioactive material),
additional monitoring of ground water near the tailings sites
may be needed to establish that the contamination is not a
result of the tailings.
4.18 GROUND WATER CLASSIFICATION
Introduction
In August 1984, the U.S. Environmental Protection Agency (EPA)
issued a Ground-Water Protection Strategy, setting out the
Agency's plans for enhancing ground-water protection efforts by
EPA and the States. A central feature of the Strategy is a
policy framework for EPA1s programs which accords differing
levels of protection to ground water based on the resource's
use, value to society, and vulnerability to contamination. A
three-tiered ground-water classification system was established
in the Strategy as a key operational tool to help implement this
policy.
The Classification system recognizes that "special" ground water
exists due to its high vulnerability to contamination and high
value for drinking water purposes or its importance to a unique
ecological habitat (Class I). The vast majority of the nation's
ground water falls within Class II which encompasses all
non-Class I current or potential sources of drinking water.
Class III ground water is not a potential source of drinking
water due to levels of contamination either from naturally
occurring conditions or the effects of broadscale human
activity, that cannot be feasibly cleaned up.
These Final Guidelines for classifying ground water augment the
Ground-Water Protection Strategy by:
o Further defining the key terms and concepts of the
classification system, and
4-191
-------
o Describing procedures and information needs to assist in
classifying ground water.
The procedures in the Final Guidelines are generally intended for
"site-specific" ground-water classification based on a review of
the segment of ground water in relatively close proximity to a
particular source. While the specific procedures are not designed
specifically for broader aquifer classification, many of the
concepts and procedures developed for site-by-site classification
will also be useful in such classification efforts.
The manner and extent to which the Guidelines will be incorporated
in EPA regulatory, permitting, and planning decisions are addressed
in a supplemental Implementation Policy Statement being issued
concurrently with the Guidelines.
The key criteria for each class, and procedural approaches for
determining whether the criteria are met are outlined as follows:
Classification Review Area
The first step in making a classification decision is defining the
area around the source that should be evaluated. Once this
Classification Review Area (CRA) has been determined, information
regarding public and private wells, demographics, hydrogeology, and
surface water and wetlands is collected and a classification
decision is made based on the criteria for each class as described
below.
The Guidelines specify an initial Classification Review Area as the
area within a two-mile radius of the boundary of the facility or
activity under review. Under certain hydrogeologic conditions, an
expanded or reduced Classification Review Area is allowed.
It should be emphasized that the Classification Review Area defines
a "study area" necessary to evaluate the appropriate ground-water
class, in connection with a specific site analysis, and not to
imply that action needs to be taken relative to other facilities
within the area.
Class I - Special Ground Water
Class I ground waters are defined as resources of particularly high
value. They are highly vulnerable and either an irreplaceable
source of drinking water for a substantial population or
ecologically vital.
o Highly vulnerable ground water is characterized by a
relatively high potential for contaminants to enter and/or
be transported within the ground-water flow system. The
Guidelines provide both quantitative and qualitative
decision aids for determining vulnerability based on
hydrogeologic factors.
4-192
-------
o An irreplaceable source of drinking water for a
substantial population is ground water whose replacement
by water of comparable quality and quantity from
alternative sources in the area would be economically
infeasible or precluded by institutional barriers. The
determination of irreplaceability is based on a three-step
process that includes identifying the presence of a
substantial population, applying screening tests designed
to produce a preliminary determination, and reviewing
relevant qualitative criteria in order to produce a final
determination.
o Ecologically vital ground water supplies a sensitive
ecological system located in a ground-water discharge area
that supports a unique habitat. Unique habitats include
habitats for endangered species listed or proposed for
listing under the Endangered Species Act as well as
certain Federally managed and protected lands.
Class II - Current and Potential Sources of Drinking Water and
Ground Water Having Other Beneficial Uses~~
Class II ground waters include all non-Class I ground water that is
currently used or is potentially available for drinking water or
other beneficial use.
Subclass IIA is a current source of drinking water. Ground
water is classified as IIA if within the Classification Review
Area there is aither (1) one or more operating drinking water
wells or springs, or (2) a water supply reservoir watershed or
portion that is designated for water quality protection by
either a State or locality.
Subclass IIB is a potential source of drinking water. This
ground water (1) can be obtained in sufficient quantity to
meet the minimum needs of an average family; (2) has total
dissolved solids (TDS) of less than 10,000 milligrams per
liter (mg/1); and (3) is of a quality that can be used without
treatment or that can be treated using methods reasonably
employed by public water systems.
Class III - Ground Water Not a Potential Source of Drinking Water
and/or Limited Beneficial Use " ~~ '
Class III drinking waters have either (1) a TDS concentration equal
to or greater than 10,000 mg/1; or (2) contamination by naturally
occurring conditions or by the effects of broadscale human activity
that cannot be cleaned up. using treatment methods reasonably
employed in public water systems. A two-step test, based on
technical and economic feasibility, is presented in the
Guidelines. Class III also encompasses those rare conditions where
yields are insufficient to meet the minimum needs of an average
household. Subdivisions within Class III include:
4-193
-------
Subclass IIIA ground water has an intermediate degree of
Tnterconnection with adjacent ground water units and/or are
interconnected with surface waters.
Subclass IIIB ground water has a low degree of interconnection
with adjacent ground water units.
4.19 REFERENCES
DOE84 U.S. Department of Energy, "Draft Environmental Assessment
of Remedial Action at the Gunnison Uranium Mill Tailings
Site," Dec 1984.
DOE86 U.S. Department of Energy, "Remedial Action Plan and Site
Conceptual Design for Stabilization of the Inactive Uranium
Mill Tailings Site at Monument Valley, Arizona," Feb 1986.
DOE86a U.S. Department of Energy, "Draft Environmental Impact ,
Statement—Remedial Actions at the Former Climax Uranium
Company Uranium Mill Site, Grand Junction, Mesa County,
Colorado," DOE/EIS-0126-D, March 1986.
EPA84 Environmental Protection Agency, "Ground Water Protection
Strategy," Washington, Aug. 1984.
EPA86a Environmental Protection Agency, "Guidelines for Ground
Water Classification under the EPA Ground Water Protection
Strategy," Final draft, Washington, Dec. 1986.
EPA86b Environmental Protection Agency, "Guidance on Remedial
Actions for Contaminated Ground Water at Superfund
Sites," EPA Contract No. 68-01-7090, Oct. 1986.
F161 Flagg, J.F., "Chemical Processing of Reactor Fuels,"
Academic Press, 1961.
Le87 Leske, D., Department of Energy, Albuquerque Operations
Office, private communication, June 1987.
NUREG80 U.S. Nuclear Regulatory Commission, Final Generic
Environmental Impact Statement on Uranium Milling,
NUREG-0706, Sept 1980.
Sm87 Smith, R.D., U.S. Nuclear Regulatory Commission, "Sampling
of Uranium Mill Tailings Impoundments for Hazardous
Constituents," Memorandum to Robert E. Browning, Director,
Division of Waste Management, NMSS, Feb 9, 1987.
4-194
-------
CHAPTER 5
GROUNDWATER RESTORATION
5.1 'TREATMENT TECHNOLOGY
Introduction
The purpose of this chapter is to identify groundwater
restoration techniques that might be applicable to the removal
and treatment of contamination at inactive uranium mill tailings
sites and to evaluate the cost ranges of applying these
techniques. The locations of the sites are shown in Figure
5.1. The groundwater treatment technologies discussed in this
summary are presently available and applicable to hazardous
wastes.
Processes and Techniques
Remedial actions that protect groundwater resources and
associated surface water resources include aquifer restoration,
elimination or limitation of the source of contamination, and
containment of the contaminated groundwater. EPA has mandated
long term, zero or minimal maintenance remedial actions for the
UMTRA Project sites (40 CFR 192). Therefore, aquifer
restoration and limitation of the source of contamination should
be the primary considerations. Containment of groundwater
should be considered only in support of aquifer restoration.
An appropriate water resource protection program at an UMTRA
Project site might include some or all of the following:
- Physical.removal of contaminated groundwater
- Temporary containment of contaminated groundwater,
intruding uncontaminated groundwater or intruding surface
water
- Treatment of contaminated water to meet appropriate water
quality standards or goals
- Isolation of the contaminant source from the hydrologic
regime
Isolation or at least partial isolation of 'the source of
contamination is implemented by the use of a multi-layered cover
above the source of contamination and possibly a layer of
selected and reworked natural materials underlying the source .of
contamination. This approach is used to limit future
contamination to non-pollutant levels and is not related
directly to aquifer restoration. Therefore, this chapter will
not discuss repository designs but will focus on the processes,
technologies and costs of contaminated ground water restoration.
5-1
-------
Ui
to
GREEN
RIVER *HIFLE(2)
• GRAND JCT
PRIORITIES
A- HIGH
• - MEDIUM
• - LOW
NOTE:
EDGEMONT, SOUTH DAKOTA
VIC8NITY PROPERTIES ONLY
FIGURE 5-1 LOCATION - UMTRA PROJECT SITES
-------
Physical Removal
Two methods can be used to remove contaminated groundwater:
trenches and wells. The methodologies and technical
considerations are discussed in this section.
Subsurface Drains/Trenches
Subsurface drains consist of underground gravel-filled trenches
lined with tile or perforated pipe which intercept leachate or
infiltrating water and transport it away from the wastes to a
suitable point for treatment and/or disposal. Subsurface drains
may be used in low permeability strata, such as clay or silty
clay with permeability insufficient to maintain adequate flow to
wells. The subsurface drain can provide a sufficient surface to
create greater discharge rates than a well or series of wells
could provide. Subsurface drains can also be used in more
permeable sand and gravel. For sand and gravel, an open trench
can be used or the permeability of the material in the trench
must be significantly greater than the surrounding soil to make
the trench effective.
Subsurface trenches are generally constructed by excavating a
trench, laying perforated pipe or tile along the bottom, and
backfilling with a coarse gravel to prevent soil fines from
penetrating and clogging the soil pores. This procedure is
confined to situations in which the contaminated groundwater is
at a depth consistent with the capabilities of the trenching
equipment, generally no more than 100 feet below the land
surface. Advantages of this type of system include low
operating costs, since flow is by gravity, considerable
flexibility in design and spacing, and fairly good reliability
when monitoring is provided.
Wells
Wells can be employed to extract or actively divert groundwater
at or near a disposal site and are effective in any porous or
fractured media which provide sufficient yields to wells. This
technology may be employed to. collect the groundwater for
treatment, contain a contaminant plume, or to lower a water
table. The number, spacing, depths, diameters, and completion
intervals of wells in a well field can be optimized to remove
contaminated groundwater cost-effectively. The goals of a
restoration program should be developed and wells positioned to
remove the specified contaminated groundwater while extracting
only a limited volume of uncontaminated water. Pumping to lower
a water table may be'appropriate under several conditions, such
as 1) lowering the water table in an unconfined aquifer so that
contaminated groundwater dose not discharge to a
hydraulically-connected receiving stream, 2) lowering the water
table so that it is not in direct contact with the waste, or 3)
lowering the water table to prevent contamination of an
underlying aquifer.
5-3
-------
Temporary Containment
Physical containment is accomplished through installation of a
relatively impermeable barrier between contaminated and clean
portions of the aquifer. Physical containment technologies
include slurry walls, grout curtains, and sheet piling.
Containment should be considered as support for physical removal
of contaminated groundwater, rather than as a remedial action in
itself. Containment methods are not proven long term solutions,
therefore their application is limited to support of physical
removal. For instance, at sites adjacent to rivers, such as the
sites in Grand Junction and Durango, containment may be
considered in controlling surface water inflow into the area of
groundwater removal. Figure 5.2 shows the effect of a cutoff
wall adjacent to a river. Also, containment may be^appropriate
where the advancing contaminant plume is approaching a presently
used water resource.
Sheet Pile Cut-Off Walls
The construction of a sheet pile cut-off wall involves driving
inter-locking piles into the ground with a pneumatic or steam
pile driver. When first placed in the ground, the sheet pile ,.
cut-off allows easy water flow through the edge interlocks.
However, with time, fine soil particles fill the seams and an
effective barrier is formed. The performance life of a sheet
pile cut-off wall can vary between seven and 40 years, depending
upon the chemical characteristics of the surrounding soil. p ._
Sheet piling is feasible in situations where the water table is
near the surface, a confining layer exists at a depth of less
than 100 feet, and surficial materials are fine-grained to allow
ease in driving the sheet metal. Sheet piling is not feasible
for use in very rocky soils or for long-term containment.
Slurry Walls
Installation of a slurry wall involves excavating a trench
through or under a slurry of bentonite clay and water, then
backfilling the trench with the original soil (with or without
bentonite mixed in). The trench is usually excavated down to a
relatively impervious substratum to limit groundwater underflow.
During the excavation process, the trench walls are supported by
the slurry, preventing the walls from slumping or caving in, and
eliminating the need for additional shoring materials. The
process is designed to force the bentonite slurry through its
own weight into the more permeable surrounding soils, forming a
filter Sake of low permeability which lines the walls and bottom
of the trench. The application of slurry walls as relatively
impermeable barriers is limited to areas where materials are
trenchable and have sufficient permeability to form a filter
cake. Trench depth is limited by the capabilities of the
trenching equipment. This technology is practical only when
groundwater contamination exists near the surface, generally
5-4
-------
LOW-PERMEABIUTY BARRIER REDUCES INDUCED
FLOW FROM RIVER
I
Ui
DISCHARGING WELL
GROUND SURFACE
RIVER
PUMPING
WATER
LEVEL
ALLUVIAL AQUIFER
Y//////////////////X///////////.
*— CONFINING LAYER
LOW-PERMEABILfTY
SLURRY WALL, GROUT CURTAIN.
OR SHEET PILING CUTOFF WALL
RGURE 5.2
-------
less than 100 feet in depth. Further, tests must be performed
as part of the remedial action process to determine whether the
slurry could be affected by chemical reactions with the
contaminants, thus rendering it unsuitable for application.
Slurry walls may be more appropriate for protecting surface
water from contamination of discharging groundwater rather than
containing the groundwater itself.
Grout Curtains
Grouting is the pressure injection of special fluids into a rock
or soil body. The fluids set or gel in the voids in the rock
and when carried out in the proper pattern and sequence, the
process forms a wall or curtain that is an effective groundwater
barrier. Due to the high cost of installing grout curtains,
they are usually used only to seal voids in porous or fractured
rock where other methods to control groundwater are not
technically feasible.
Treatment Processes
After contaminated groundwater has been collected, the next step
in aquifer restoration involves treatment of the water and the
eventual reinjection into the groundwater or discharge to
surface water. A variety of methods has been successfully
employed in treating groundwater contaminated with typical
contaminants (e.g. uranium, metals, sulfate and dissolved
solids). Examples are chemical precipitation, evaporation, ion
exchange, neutralization, and sorption.
Chemical Precipitation
The chemical precipitation process removes dissolved metals from
aqueous wastes 'by chemically converting the metals into
insoluble forms. The process is illustrated in Figure 5.3.
Metals may be precipitated from solution as hydroxides,
sulfides, carbonates or other salts. Hydroxide precipitation
with lime is most common; however, sodium sulfide is sometimes
used to achieve lower effluent metal concentration. . This
involves pH adjustment followed by the addition of sodium
sulfide and a flocculant. Solids separation is achieved by
standard flocculation—coagulation techniques. The resulting
residuals are metal sludge and the treated effluent with an
elevated pH and, in the case of sulfide precipitation, excess
sulfide.
This technology is used to treat aqueous wastes containing
metals, including zinc, arsenic, copper, manganese, mercury,
cadmium, trivalent chromium, lead and nickel. A disadvantage' of
the method is that the pH which would precipitate one metal may
allow other metals to remain soluble. Therefore, it may be
difficult to attain an optimal pH for a given mix of metals.
Also, chelating or complexing agents may prevent metals from
5-6
-------
CHEMICAL PRECIPITATION AND ASSOCIATED PROCESS STEPS
CHEMICAL
PRECtPITANTS
Ln
I
LIQUID
PRECJPfTATOR
TANK
CHEMICAL
FLQCCULANTS/
SETTUNG AIDS
RjOCCULATION
WELL
FLOCCULATING
PADDLES
FLQCCULATOR-
CLARIF1ER
EFFLUENT
BAFFLE
SLUDGE
RGURE 5.3
-------
precipitating. Sulfide precipitation has been successfully used
in numerous applications and often achieves lower concentrations
levels than lime precipitation. However, the process does
require close monitoring to function properly.
Most uranium milling operations employed acid leach processes to
extract uranium. Therefore/ chemical precipitation initiated by
increasing the pH can be very effective in reducing the
concentrations of radium, thorium, uranium, selenium,1 arsenic,
cadmium, chromium, other trace metals and sulfate. Although
some chemical precipitation resulted from neutralization in the
subsoils at most sites due to the abundance of calcite in the
soils, enhanced precipitation may be applied with a treatment
plant to further lower the concentrations of metals that complex
with mobile anions. Sulfide precipitation may be most effective
in this enhanced treatment.
Evaporation
Evaporation is defined as the physical separation of a liquid
from a dissolved or suspended solid by the application of energy
to volatilize the liquid. Evaporation may be used to
concentrate a hazardous or toxic material, thus reducing the
volume of waste requiring subsequent treatment of disposal.
Evaporation can be carried out in a large pond with sunlight
providing the energy.
Most uranium milling sites are in semi-arid climates where
potential evaporation greatly exceeds precipitation. Therefore,
a pond to evaporate discharged groundwater from dissolved
contamination is a potentially viable treatment technique.
Following evaporation, the residual solids could be incorporated
into the tailing repository for "permanent" disposal.
Ion Exchange
Ion exchange removes toxic metal ions from solution by
exchanging one ion, electrostatically attached to a solid resin
material, for a dissolved toxic ion. The process is illustrated
in Figure 5.4. The resulting residuals include spent resins and
spent regenerants such as acid, caustic or brine. This
technology is used to treat metal wastes including cations
(Ni2+, Cd2+, Hg2+) and anions (chromates, selenates,
arsebates). The effectiveness of the process may be limited by
competition for exchange sites between contaminated metals.
Other disadvantages are difficulties in obtaining and
maintaining an optimal pH for efficient removal and the
inefficiency of the process in treating groundwater with high
concentrations of suspended solids. The oxidizing agent
concentration should be greater than 50 milli-equivalent per
liter (meq/1) for practical operation. Highly concentrated
waste streams (>2500 mg/1 contaminants) or high solid
concentrations (>50 mg/1) should be avoided.
5-8
-------
FIGURE 5.4
SCHEMATIC OF ION EXCHANGE
TO STORAGE TANK OR
OTHER TREATMENT SYSTEM
TO STORAGE TANK OR
OTHER TREATMENT SYSTEM
INFLUENT
WASTEWATER
BACKFLUSH
WATER
ACID
REGENERANT
CATION EXCHANGE
SYSTEM
BACKaUSH
WATER
TREATED
WASTEWATER
CAUSTIC
REGENERANT
ANK>N EXCHANGE
SYSTEM
TO STORAGE TANK OR
OTHER TREATMENT SYSTEM
TO STORAGE TANK OR
OTHER TREATMENT SYSTEM
5-9
-------
Neutralization
Neutralization renders acidic or caustic wastes non-corrosive by
adjustment of the pH. The residuals include insoluble salts,
metal hydroxide sludge, and neutral effluent containing
dissolved salts. The final desired pH is usually between 6.0
and 9.0.
Neutralization is used to treat corrosive wastes, both acids and
bases. A disadvantage of the process is the need to dispose of
highly concentrated sludges and solids.
Significant neutralization occurs at Western uranium milling
sites directly beneath and downgradient of the tailings source
material due to calcite in the shallow soils. The
neutralization causes precipitation of gypsum and the
coprecipitation, occlusion and adsorption of radionuclides and
trace metals.
Sorption
Contaminants are bound up in pozzolan-type matrices by physical
sorption or chemisorption yielding a stabilized material which
is easier to handle. The process is illustrated in Figure 5.5.
Liquid immobilization depends on added ingredients. This
process results in high concentrations of contaminants at the
surface of the material and contaminants may leach. The treated
material is permeable.
Sorption can be used for organics and inorganics. The
advantages to this technology are that raw materials are readily
available, the mixing technology is known, the waste form is
relatively easy to handle, additives are inexpensive, minimum
pretreatment is required, and bearing strength is adequate for
landfill. Disadvantages are that large volumes of additives are
needed, the results are sensitive to the placement and packing
of the matrices, free water may be released under pressure and
changes in temperature may affect the results.
Landfarming
Landfarming is a technique where contaminated soil is
incorporated into the top 6 to 8 inches of soil along with
concentrated microbial populations. It is used to biodegrade,
volatilize or leach organics. It is not applicable to the
inorganic contamination at uranium milling sites (WESTON, 1983).
,B^>
Reverse Osmosis
Reverse osmosis is a membrane process to remove dissolved ions
from saline water using hydrostatic pressure to drive the
feedwater through a semipermeable membrane. The major portion
•of the ions remain on the feed side of the membrane, and is
5-10
-------
FIGURE 5.5
SCHEMATIC OF CARBON ADSORPTION
UQUIO
CARBON
ADSORPTION
COLUMN
H
TO SERVICE
JT
f
CARBON
ADSORPTION
COLUMN
12
SPENT CARBON
(ONE UNIT CHANGED
PER TIME)
TO
REGENERATION
5-11
-------
discharged as waste. The osmotic pressure needed for successful
treatment can be estimated as 1 psi/100 mg/1 of TDS.
Modern reverse-osmosis membranes are constructed in a modular
form, most common are spiral wound and hollow fine fiber. The
modules are mounted in containment pressure vessels. Reverse
osmosis is most successful in treating water with less than
10,000 mg/1 TDS to produce water with less than 500 mg/1, i.e.,
potable quality (Montgomery, 1985). The cost for reverse
osmosis ranges from $500 per million gallons treated for water
containing approximately 10,000 mg/1 TDS to $1500 per million
gallons treated for water containing approximately 30,000 mg/1
TDS (Thompson, 1987).
In Situ Treatment
There are three general categories of in situ treatment
processes for the remediation of contaminated ground water:
biological, chemical, and physical. Of these,-only the chemical
treatment technologies are generally capable of neutralizing or
immoblizing the ground water contaminants normally found at the
UMTRA sites. In situ chemical treatment involves the injection
of chemicals into the contaminated aquifer under carefully
controlled conditions to immobilize or neutralize the
contaminants. Typical chemical treatments include neutralizing
the pH to induce precipitation of contaminant cations and/or
anions, change of chemical forms to encourage chelation, and
formation of compounds which are less mobile or less degrading
to water quality.
Implementation would require extensive characterizations of the
local geology, hydrology and geochemistry, followed by
site-specific pilot testing. The site geology, hydrology, and
geochemistry must allow adequate contact between the treatment
agents and the contaminated ground water, control migration of
the treatment agents and the contaminants, and allow recovery of
spent solutions and/or contaminants if necessary. If pilot
tests indicated the method to be feasible, project costs would
include installation of wells and pumps for injection,
withdrawal and monitoriing, facilities for handling the
chemicals for treatment, control sampling, etc. Costs for a
well field and ground water pumping would be 500 to 1500 dollars
per million gallons. Costs for treatment of the water and
reinjection are estimated at 500 dollars per million gallons.
Total costs should be much less than typical chemical treatment
since it is estimated that only 20% to 50% of the contaminated
ground water would be pumped, treated, and reinjected.
5.2 VOLUMES OF CONTAMINATED GROUND WATER
Introduction
Prom a technical standpoint, three factors govern the
feasibility, effectiveness and costs of aquifer restoration.
5-12
-------
These are 1) the volume of contaminated groundwater, 2) the ease
with which it can be removed, and 3) its treatability. When a
vast volume of groundwater is contaminated or when an aquifer is
hydraulically connected to a surface water body, it may neither
be technically nor economically feasible to pump, treat, and
recharge the contaminated wastes. Similarly, in a situation for
which the aquifer is thin, discontinuous, heterogeneous, or of a
low permeability, aquifer restoration also may not be feasible.
Finally, while it may be technically and economically feasible
to collect contaminated groundwater, it is possible that the
type and/or levels of contamination may not be treatable. These
factors must all be considered in selecting the scope of aquifer
restoration and the applicable technologies.
Site Descriptions
In this section, each of the sites is described, with emphasis
on the estimated volume of contaminated groundwater, the
appropriate method to extract the contaminated groundwater, and
the value of the contaminated groundwater relative to its
present or potential use. Volumes of contaminated groundwater
are summarized in Table 5.1.
Ambrosia Lake
The estimated volume of contaminated g.roundwater at the Ambrosia
Lake site is 650 million gallons. The tailings lie on
unconsolidated materials. The shallow groundwater occurs 10 to
40 feet beneath the ground surface. The deeper tailings are
saturated. The groundwater contained in the tailings, alluvium,
fractured Mancos Shale, and Tres Hermanos Sandstone probably
resulted for surface discharges of mine dewatering. Given that
the depth of contamination is relatively shallow and yields to
wells are minimal, contaminated groundwater could be extracted
more efficiently with trenches than with wells. Following
remedial action, given that mining and dewatering has ceased in
the area, the contaminated groundwater will probably dissipate
through discharge into the mine shaft in the Wastewater Canyon
Member of the Morrison Formation and the presently saturated
shallow zones will desaturate.
Canonsburg
The volume of contaminated groundwater at the Canonsburg site is
approximately 100 million gallons. The remedial action at the
Canonsburg site was completed in 1986. Groundwater at the
expanded Canonsburg site is unconfined in' the unconsolidated
material (fill, soil, and alluvium) and is semi-confined in the
underlying bedrock. Given that the contamination is relatively
shallow, trenches would appear to be the preferred method for
groundwater removal. Depth to groundwater is zero to eight
feet. Recharge to the unconsolidated material is from direct
infiltration of precipitation and from groundwater flow onto the
5-13
-------
expanded Canonsburg site from the south. Chartiers Creek is the
discharge area on the western, northern, and eastern sides of
the site for the unconfined groundwater. Groundwater in the
shallow bedrock may pass beneath the site. Groundwater in the
area has very limited use for gardening and other outdoor uses.
Durango
Subsurface investigations at the Durango site were limited by
the steep, unstable slopes of tailings and smelter slag at the
site. A rough estimate of the volume of contaminated
groundwater at the site is 500 million gallons. The depth to
groundwater ranges from approximately ten to 50 feet below land
surface. The contamination is primarily in the alluvium and is
naturally contained by a thick bed of Mancos Shale underlying
the alluvium. Trenching would be preferred over pumping to
extract contaminated groundwater due to the relatively shallow
depth of contamination. The site is within 500 feet of the
Animas River. A cut-off wall may be necessary during aquifer
restoration to prevent the inflow of surface water from the
Animas River.
Grand Junction
The volume to contaminated groundwater at the Grand Junction
site is approximately 700 million gallons. Shallow unconfined
groundwater occurs in the alluvium on the Colorado River and is
separated from confined groundwater by approximately 200 feet of
relatively impermeable Mancos Shale. Shallow groundwater is not
used in the area. Most of all of the contaminated groundwater
could probably be removed with trenches. A cutoff wall may be
required during groundwater removal to limit the inflow of water
from the Colorado River. Return irrigation flow passes under
and possibly through the tailings pile. The water table over
much of the site rises above the base of the 'tailings. During
most of the year, shallow groundwater flows toward the Colorado
River. Water quality analyses indicate no river contamination
due to tailings seepage.
Gunnison
Approximately two billion gallons of groundwater are
contaminated at the Gunnison site. Shallow groundwater is the
major water supply in the Gunnison area. The Gunnison site
rests on a massive alluvial deposit that is more than 100 feet
thick. It rests at the confluence of two large regional
groundwater aquifers comprised of the Gunnison River and Tomichi
Creek water sheds. The depth of the groundwater varies by six
to eight feet annually and is near or above the base oJ: the
tailings during the summer months. Contamination may be_up to
approximately 100 feet deep. Because the contamination is
relatively deep, covers a broad area and the sediments are
5-14
-------
relatively permeable, pumping is the preferred method for
groundwater extraction for aquifer restoration.
Lakeview
The estimated volume of contaminated groundwater at the Lakeview
site is three billion gallons. Groundwater at depths greater
than 100 feet is the major water supply in the Lakeview area.
The depth of contamination is approximately 50 to 75 feet below
land surface. Groundwater occurs under both confined and
unconfined conditions with a water table that varies seasonally
from zero to 15 feet below the ground. Because the
contamination is relatively deep and the sediments are
relatively permeable, pumping is the preferred method for ground
water extraction for aquifer restoration.
Mexican Hat
The estimated volume of contaminated groundwater at the Mexican
Hat site is 90 million gallons. The tailings rest on very
dense, tight siltstone. The Mexican Hat site is about five
miles away from the nearest exposure of permeable strata.
Except for areas of local ponding, the fine-grained nature of
the tailings and the high evaporation rates of the region allow
only limited:amounts of precipitation to infiltrate into the
tailing. Capillary forces in the tailings may be sufficient to
preclude percolation of tailings water to the underlying
bedrock. The depth to the water table is not known but is
assumed to be greater than 50 feet. Because the contamination
is relatively deep, pumping would be the preferred method to
remove groundwater for aquifer restoration. The ambient water
quality is poor (only industrial use is possible without
extensive treatment).
Monument Valley
Approximately three billion gallons of contaminated groundwater
lie beneath and downgradient of the Monument Valley site.
Shallow groundwater is used by several local dwellers. The
tailing piles are all sand (no slime), all precipitation is
absorbed and there is little evidence of any surface runoff from
the_piles. The rock unit that forms the shallowest confined
aquifer near the mill site is the Shinarump Conglomerate Member
of the Chinle Formation. This rock unit is exposed immediately
west of the tailings piles, and most of the abandoned mill
building foundations and settling pond sites are located on
outcrops. The Shinarump Member consists of poorly sorted sand,
grit, and pebble-size conglomerate. Unconfined groundwater is
very near the surface along the main axis of Cane Valley Wash.
The unconfined water moves through the alluvium of Cane Valley
Wash and .is recovered near the site from shallow wells. These
shallow wells and springs are recharged from local runoff.
Contamination extends to depths of up to 100 feet. The depth
5-15
-------
and large area of contaminated groundwater and relatively
permeable soil and rock indicate that pumping is the preferred
method of groundwater extraction for aquifer restoration.
Riverton
The volume of contaminated groundwater at the Riverton site is
approximately one billion gallons. Groundwater levels are
generally less than six feet below the tailings foundation
interface and periodically groundwater rises toward and into the
lower portions of the tailings pile. A confined aquifer system
is present in the underlying bedrock. The unconfined system and
the first confined system are separated by about 25 feet of
shale, siltstone, and mudstone bedrock. The unconfined
groundwater quality is briny and is not a source of potable
water. The unconfined aquifer has been contaminated.
Contaminated groundwater could be removed using trenches. The
confined groundwater is a major source of potable water in the
Riverton area. It has not been contaminated as indicated by
most of the site groundwater quality data.
Salt Lake City
The volume of contaminated groundwater at the Salt Lake City
site is estimated to be 1.6 billion gallons. The Salt Lake City
site is underlain by an unconfined aquifer which overlies a
confined aquifer. Both aquifers consist of interbedded clays,
silts, and sands. The shallow groundwater has been
contaminated. Trenching could be used to extract the
contaminated groundwater. Hydrologic- data indicate the
unconfined aquifer is about 60 feet thick near the site. The
unconfined aquifer is recharged by upward leakage from the
confined aquifer and infiltration of precipitation and
snowmelt. The unconfined aquifer is generally encountered
initially at a depth of about 75 feet. The major source of
recharge to this aquifer is infiltration of precipitation and
runoff from the foothills of the Wasatch Mountains. .The flow
direction in both aquifers is to the west and northwest. The
confined aquifer has not been contaminated significantly. The
unconfined aquifer is characterized by very high total dissolved
solids, iron, sulfate, and sodium, and is not usable as a
potable water supply anywhere in the area. The confined aquifer
is potable and will continue to be used as a water supply.
Shiprock
The volume of contaminated groundwater beneath the site is
estimated to be 850 million gallons and the contamination of the
floodplain deposits along the San Juan River is estimated to be
400 million gallons. Groundwater characterized by TDS in excess
of 20,000 ppm exists in the alluvial deposits and weathered
Mancos Shale between 13 and 50 feet below the surface underlying
the tailings repository. The relatively flat, shallow
5-16
-------
groundwater gradient is towards the escarpment above the flood
plain of the San Juan River where only slight seepage has been
found. The shallow groundwater is contaminated beneath the
tailings; however, it is separated by hundreds of feet of
relatively impermeable Mancos Shale from the regional aquifer.
The contaminated groundwater in the floodplain deposits below
the escarpment along the San Juan River could be extracted with
trenches. Floodplain groundwater is used for all purposes by
local dwellers across the San Juan River from the site. Removal
of the contamination beneath the site may require pumping.
Tuba City
Approximately 1.2 billion gallons of groundwater in the Navajo
Sandstone has been contaminated at the Tuba City site. The
principal aquifer and water supply in the Tuba City-Moenkopi
area is a multiple-aquifer system consisting of Navajo Sandstone
and some sandstone beds in the underlying Kayenta Formation.
This aquifer is recharged by winter and spring precipitation in
the Kaibito Plateau highlands some distance north of Tuba City.
The depth to the water table is approximately 50 feet.
Contamination has extended to depths of up to 150 feet/
therefore wells would be needed to extract the contaminated
groundwater.
5.3 AQUIFER RESTORATION COST RANGES
Unit costs ranges for groundwater removal methods, cut-off walls
and treatment methods are presented in Table 5.2. The likely
unit costs are also presented.
5-17
-------
Table 5.1
SITE
Volumes of Contaminated Ground Water at Selected
Inactive UMT Sites
AMOUNT OF CON-
TAMINATED WATER
(MGAL)
, MIN : MAX
AMOUNT OF CON-
TAMINATED WATER
(MGAL)
LIKELY
Ambrosia Lake
Canonsburg
Durango
Grand Junction
Gunnison
Laheview
Mexican Hat
Monument Valley
River ton
Salt Lake City
Shiprock
Tuba City
500
75
300
500
1500
2500
60
2500
800
1200
1000
1000
BOO
125
700
900
2500
3500
120
3500
1200
2000
1500
1500
650
100
500
700
2000
3000
90
3000
1000
1600
1250
1250
TABLE 5.2. UNIT COSTS FOR GROUND WATER RESTORATION METHODS
TREATMENT METHODS
TOTAL COST (DOLLARS)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
Slurry Wall
Grout Curtains
Sheet Pilings
Subsurface Drains
Evaporation Ponds
Groundwater Pumping
Chemical Precipitation
Ion Exchange
Neutralization
Sorption
Reverse Osmosis
In Situ Treatmemt
54.
162.
00
00
- 110.00/Cubic
- 330.00/Cubic
Yard
Yard
15.00/Sq Ft of Wall-
500.
1.
500.
500.
500.
500.
1000.
500.
1000.
00
50
00
00
00
00
00
00
00
- 1000.00/MGAL
- 5.00/Sq Foot
- 1500.00/MGAL
- 1200.00/MGAL
- 1000.00/MGAL
- 1200.00/MGAL
- 1400.00/MGAL
- 1500.00/MGAL
- 2000.00/MGAL
Treated
of Pond
Treated
Treated
Treated
Treated
Treated
Treated
Treated
Likely Unit Costs (DOLLARS)
ITEM
MIN.
MAX.
LIKELY
Containment (/FT2)
Pumping (/MGAL)
Trenching (/MGAL)
Treatment (/MGAL)
10
500
500
500
20
1500
1000
1400
15
1000
750
950
5-18
-------
5.4 REFERENCES ' •:
Clean-up of Chemical Contaminated Site, Chemical Engineering,
February 21, 1983, V90, n4, p.73(9)
Environmental Assessment of Remedial Action at the Riverton
Uranium Mill Tailings Site, U.S. Department of Energy,
DOE/EA-0254, July 1985
Handbook, "Remedial Action at Waste Disposal Sites." USEPA, EPA
625/6-82-006
Handbook, "Leachate Plume Management." USEPA, EPA 5-40/2-85/004
Jacobs Engineering Group, "Aquifer Protection and Restoration
Alternatives and Cost Considerations"
Lauch, R.P., and Cuter, G.A., "Ion Exchange for the Removal of
Nitrate From Well Water." Journal AWWA, 78:5:83, May 1986
Montgomery, James M. "Water Treatment Principles and Design",
John Wiley & Sons, Inc., 1985.
Sorg, T.J., "Treatment Technology to Meet the Interim Primary
Drinking Water Regulations for Inorganics," Journal AWWA,
70:2:105, February 1978
Summary Report, "Remedial Response at Hazardous Waste Sites,"
USEPA, EPA 540/2-84-002 A & B
Thompson, Bruce, Personal Communication, University of New
Mexico, May 1987.
Wagner, K., and Z. Kosin. 1985. In situ treatment. In: The
Sixth National Conference on Management of Uncontrolled
HazardoustWaste Sites, November 4-6, 1985, Washington, D.C.
Hazardous Materials Control Research Institute, Silver Spring,
MD.
Roy F. Weston, "Installation Restoration General Environmental
Technology Development," Report No. DRXTH-TE-CR-83249, December
1983.
Roy F. Weston, "Solvent and Heavy Metals Removal from
Groundwater," Report No. DRXTH-TE-CR-82176, January 1983.
5-19
-------
-------
CHAPTER 6
COSTS OF GROUND WATER RESTORATION AND MONITORING
The costs of ground water restoration can vary greatly among
sites, as discussed in the previous chapter. The purpose of
this chapter is to consider the major capital and operation cost
components to arrive at a single estimate of the total ground
water cleanup cost for all 24 sites. The major cost components
are the amount of contaminated ground water, the amount of
contaminated ground water that must be removed from below the
surface, and any treatments that must be given the contaminated
ground water. Costs are also estimated for monitoring of ground
water and at water treatment plants.
6.1 AMOUNT OF CONTAMINATED GROUND WATER
The volume of ground water that is contaminated is estimated
from well data and the geological structure in the locale of the
tailings pile. Well data indicate the area of the contaminated
plume and also provide some characteristics of the local
geology. The presence of confining layers (aquitards) limits
the vertical spread of the contamination, unless there are
interconnections with other aquifers. The vertical distance
between confining layers when combined with the area of the
contaminated plume yields the volume of the contaminated
aquifer. The volume of water is determined using the porosity
of the rocks in the aquifer.
The many variables in this determination lead to uncertainty.
Estimated uncertainties in the amount of contaminated water
shown in Table 5.1 range from +_ 17% to _+ 40% from the midpoint
values. Since there is no evidence that these volumes are
skewed (i.e., purposefully over- or under-estimated), the
midpoint values are used to estimate total costs. The volumes
of contaminated ground water are listed in Table 6.1.
6.2 AMOUNT OF GROUND WATER TO BE REMOVED
The total cost of ground-water restoration is directly
proportional to the total amount of ground water that must be
processed. Typically, this total quantity of water is expressed
as the number of volumes of contaminated ground water that must
be removed to restore ground-water quality. For example, the
amount of contaminated ground water at Ambrosia Lake is 650
million gallons (Mgal). If the total amount of ground water to
be processed is five volumes, the total amount is 3250 Mgal.
6-1
-------
Table 6.1 Aquifer Restoration Cost Estimates
Site
Amount of
Contaminated
Water
(106 gal)
Pumping
Cost
(106 $)
Trenching
Cost
(106 $)
Treatment
Cost
(106 $)
Containment
Cost
(106 *)
Ambrosia Lake 650
Canonsburg 100
Durango 500
Palls City 4000
Grand Junction 700
Gunnison 2000
Lakeview 3000
Maybell 180
Monument Valley 3000
Rifle - New 700
Riverton 1000
Salt Lake City 1600
Shiprock 1250
Slick Rock - NC 30
Slick Rock - DC 23
Spook 180
Tuba City 1250
Install Operate
2.50 7.50
3.75 11.25
3.75 11.25
2.44
0.38
1.88
2.63
2.63
3.75
6.00
4.69
0.11
0.09
0.68
Install Operate
1.56
4.69
0.62
0.10
0'.48
0.67
1.90
2.85
2.85
0.67
0.95
1.52
1.19
0.03
0.02
0.25
1.19
2.47
0.38
1.90
2.66
7.60
11.40
11.40
,66,
,80
6.08
4.75
0.11
0.09
0.86
4.75
1.4(0
(a) Cost estimates are for processing five volumes of contaminated water over
15 years. Unit costs are $15/sq. ft. for containment, $l,000/Mgal for
pumping, $750/Mgal for trenching and $950/Mgal for treatment.
(b) Assumes all water is treated. These costs may be much less for some sites
if effluent limitations guidelines are met for direct discharges to rivers,
or if land disposal is feasible.
(c) Containment area is 62,500 sq. ft.
(d) Containment area is 35,000 sq. ft.
6-2
-------
Estimating the number of volumes to be extracted on a generic
basis is uncertain. Restoration is greatly dependent on the
chemical characteristics of the aquifer rock, which can be
expected to vary widely among sites. In a review ;of in situ
uranium mining at eight sites (NUREG86), considerable
variability was found in the number of volumes needed to
significantly reduce hazardous constituents in the ground
water. Restoration of the ground water at these sites was
complicated due to the processing solvent (lixiviant) that was
used to dissolve the uranium. An important finding was that,
for those cases where significant restoration was achieved,
almost all the cleanup occurred in the first few volumes removed.
Based on the discussion in Chapter 5, a value of five volumes of
contaminated ground water is selected as the best quantity for
estimating costs of restoration. Selective chemistry may be
used at some sites to enhance restoration, as well as injection •
of treated (clean) water to flush (sweep) contaminants from the
aquifer. Such actions are site specific and not amenable to
assessment in this generic analysis.
6.3 TREATMENT OF CONTAMINATED GROUND WATER
Treatment costs vary from $500.00 to $1,400.00 per Mgal treated
(See Table 5.2). Since seven treatment methods are available
for application at any particular site, it appears likely that
the midpoint of the cost range can be achieved when averaged
over all sites. Therefore, the midpoint value of $950.00 per
Mgal of water treated is selected for use in this assessment.
6.4 ESTIMATED COST OF RESTORATION TREATMENT
The estimated cost of ground water restoration is .shown in Table
6.1 for the sites for which sufficient data are available. The
procedure includes:
o A choice is made whether trenches or wells would be the
preferred method of groundwater removal. Then the unit
cost range is applied for the chosen method.
o Cut-off wall costs are estimated for the two sites where
river inflow may need to be controlled.
o Site-specific treatment methods are not specified
because the unit cost ranges do not vary significantly
between the various treatment methods. A treatment cost
of $950 is used for all sites.
o It is assumed that five times the volume of contaminated
ground water needs to be extracted to restore adequate
ground water quality.
6-3
-------
The cost estimates include, the major items required in ain
aquifer restoration program and assume that all ground water
must be restored at all sites by treatment. Some of the items
not included in the cost estimates are:
- monitoring equipment
- data collection
- discharge or reinjection facilities and operations
- removal amd remediation of facilities
- final revegetation and well abandonment.
Pumping costs and treatment plant operating costs are costs that
will occur over a period of 5 to 53 years (DQE'88c). Therefore,
estimating the operating costs separately will allow the present
value of these costs to be estimated. The values for the
operating costs and present worths at 5% and 10% are presented
in Table 6.2. • ,
6.5 ESTIMATED COST OF MONITORING
Monitoring costs will be incurred both at the" treatment plants
and for ground-water sampling at wells. The cost estimates for
monitoring are developed separately in this section.
6.5.1 Estimated Monitoring Costs at Treatment Plants
Monitoring at the treatment plant consists of collecting
composite samples of the inflow water and the outflow water on a
routine schedule. These samples are analyzed for indicator
nuclides or chemicals that denote that the process is working
efficiently and that discharge quantities are.within
specifications. The frequency of these analyses varies due to
several factors, including the rate of change in inflow
concentrations and process upsets in the plant.
The estimated cost of monitoring at the treatment plants is '
based on information supplied by DOE (DOE 88b). DOE estimated
that ground water would require treatment at 17 sites, that the
period of operation of treatment plants would vary from less
than 5 years to 53 years, that the monitoring frequency schedule
could be reduced over the operating lifetime as:
6-4
-------
Table 6.2 Ground-Water Restoration Cost Estimates
at 17 Sites Chosen by DOE for Active Restoration
Operating
Site Time
(years)
Ambrosia
Canonsburg
Durango
Falls City
Grand June
Gunnison
Lakeview
Maybell
Monument V
Naturita
Rifle-New
Riverton
Shiprock
Slick-NC
Slick-UC
Spook
Tuba City
10
5
5
53
5
5
5
5
23
5
5
13
5
5
5
32
22
Cost ( $M)
(a)
Install Operate
3,06
.48
2.36
15.00
3.30
4.40
6.60
.93
6.60
.36
3.30
4.70
5.88
.11
.09
.93
2.75
60.85
170
2.47
.38
1.90
(b) 19.00
2.66
15.10
22.65
(b) .86
22.65
(b) .45
2.66
3.80
4.75
(b) .14
(b) .11
(b) .86
9.44
109.88
.73
at
5%
Operate Total
1.91
.33
1.65
6.63
2.30
13.08
19.61
.74
13.28
.39
2.30
2.75-'
4.11
.12
.10
.42
5.65
4.97
.81
4.01
21.63
5.60
17.48
26.21
1.67
19.88
.75
5.60
7.45
9.99
.23
.19
1.35
8.40
136.22
at
10%
Operate Total
1.52
.29
1.44
3.56
2.02
11.45
17.17
.65
8.75
.34
2.02
2.08
3.60
.11
.08
.26
3.76
4.58
.77
3.80
18.56
5.32
15.85
23.77
1.58
15.35
.70
5.32
6.78
9.48
.22
.17
1.19
6.51
119.95
(a). Costs are from Table 6.1
(b) Assumes trenching used to collect contaminated ground water
6-5
-------
Percent of
operating
period
10,
20
30
20
20
Monitoring
frequency
schedule
daily
3 days/week
weekly
semimonthly
monthly
Samples
(analyses)
per year
730
312
104
48
24
and that the analysis cost per sample would be $600. E^or a
treatment plant operating 10 years, the total number of samples
would be 730 + 624 + 312 + 96 + 48 = 1810 and the estimated cost
of monitoring would be $1,086,000 at $600 per sample. The total
estimated monitoring cost for the 17 plants operating for
various periods would be $23 million. This cost at a 5% present
worth rate is about $17 million and at 10%, is about $13 million.
6.5.2 Estimated monitoring costs of ground water
Monitoring of the contaminated ground water consists of
collecting ground water from wells that terminate in the
uppermost aquifer and any other aquifers that are hydraulically
connected to the uppermost aquifer. The number of wells must be
sufficient to adequately define the contaminated plume,
Guidance is available for estimating the number of wells
(EPA 86), but for these cost estimates the number of wells
already in use is used. For those sites where no information is
available, the average of 25 wells per site is used.
Frequency of sampling is quarterly,. consistent with the 40 CFR
264.99 rule. The cost of analyzing each sample is $600 (DOE
88b). The length of time that compliance monitoring must be
conducted is assumed to be during the operating period of the
treatment and for a 5-year period after standards are achieved
in ground water (after shutdown of the treatment plant). These
times vary from 10 years to 58 years in these estimates.
The total estimated cost of monitoring ground water is $21
million at the 17 sites that DOE currently identifies as
requiring ground-water restoration. The estimated present value
of ground-water monitoring at a 5% rate is about $11 million and
at a 10% rate, is about $8 million.
6.6 TOTAL ESTIMATED COSTS
The total estimated cost for ground-water restoration including
monitoring is $214 million at the 17 sites that DOE currently
projects require restoration. The cost of ground-water
monitoring is estimated by DOE (DOE 88c) as $24 million at the
remaining 7 sites. The grand total for all 24 sites is then
about $240 million. The present worth of this grand total at 5%
is about $190 million. The present worth of the grand total at
10% is about $160 million.
6-6
-------
Using a combination of cleanup and natural cleansing will also
reduce costs. In this instance, partial cleanup, which appears
to be most efficient (see Section 6.2), is performed to reduce
contamination to levels that will be cleansed by natural
processes within the extended remedial period limit. This can
significantly reduce costs by reducing the amount of water
requiring processing to perhaps two or three times the
contaminated volume (rather than five times). The
implementation of institutional controls is not costly.
Costs could also be reduced if permission could be obtained to
discharge contaminated ground water to rivers or to land : ..
treatment (land farming) facilities (e.g., Christmas tree farm),
rather than treat it. For example, if the uranium concentration
is less than 2 mg per liter, which is the effluent limitations ;
guidelines for the discharge of waste water from uranium mines
(40 CFR 440), and if all other numerical limits in the
guidelines and BADT requirements are met, it appears it may be
possible to discharge the contaminated water to a river.
Likewise, it may be possible to discharge contaminated ground
water to land treatment facilities provided that the^ :,.•-.. -
requirements of 40 CFR 268 are met. However,, these
possibilities are site specific to the extent that cost cannot
be estimated on a generic basis.
6.7 REVIEW OF DOE COST ESTIMATES
6.7.1 DOE Cost Estimates
DOE submitted comments on the proposed rule during January
1988. These included an appendix presenting cost estimates for
restoration and monitoring of contaminated ground water (DOE
88a). During May 1988, DOE provided EPA with additional cost
estimates that were called "Attachment A Reestimation of
Aquifer Restoration Costs" (DOE 88b). Further, DOE submitted a
report entitled "U.S. Department of Energy Final Response to
Standards for Remedial Actions at Inactive Processing Sites"
'during November 1988 which included a table with an estimated
groundwater restoration project cost (DOE 88c).
The DOE January 1988 estimate was based on information on the
extent of groundwater contamination at five sites. These
estimates were then extrapolated to all 24 sites using a
"similar site" approach. The total volume to be pumped and
treated or discharged was estimated by adding to the current
contaminated water volume, the volume that would be needed to
flush 10% of the contaminants that are adsorbed on soils. DOE
estimated the base cost as $746 million. DOE applied a "project
factor" of 2.3 to obtain their total cost estimate of J51,715
million.
6-7
-------
The DOE May 1988 submittal included nine additional cost
estimates. The base cost for restoring ground water at all 24
sites combined ranged from a total of $393.71 million to $745.68
million. For some of these estimates, DOE reduced the "project
factor" from 2.3 to 1.424 and reduced the estimate for one site
as discussed below, yielding a new total cost range of $560.65
million to $1,715.07 million.
The DOE November 1988 submittal included an estimated project
base cost of $664 million and an estimated base plus contingency
cost of Ł760 million, both in 1989 dollars. This report also
provided an escalated project cost of $985 million after
applying standard federal escalation rates through 1994 with no
escalation beyond 1994.
6.7.2 Evaluation of DOE Cost Estimates
In the DOE January 1988 estimate, one site, Falls City, Texas,
accounts for 47% ($348 million of Ł746 million) of the total
base cost. The volume of contaminated ground water at Falls
City is large. The principal hazardous contaminants are
uranium, molybdenum, chromium, nitrate, and radium-226. In
fact, the estimated mass of uranium-contaminated ground water at
Falls City is 98% of the total mass from all 24 sites. Also,
the quantity of uranium adsorbed on soil is among the four
greatest at the 24 sites. Likewise, the estimated mass of
molybdenum in ground water is 93% and of chromium is 95% of the
total from all 24 sites.
In the DOE May 1988 material, the costs were reestimated by
varying 3 different factors: the number of water treatment
plants needed at the Falls City site, the monitoring frequency
of ground water and of the inflow and outflow of the water
treatment plant, and the project factor. The results of this
reestimation are summarized in Table 6-3.
A large reduction in costs is achieved by using one treatment ,,
plant at Falls City instead of three. Four different aquifers
are contaminated at Falls City. In the initial estimate DOE
extrapolated cost estimates from other sites, including a } ia
treatment plant for each of the three major contaminated :,\
aquifers (the contaminated water from the fourth aquifer was to
be treated at one of these three). Since the cost of extracting
ground water at Falls City is low (it can all be done by
trenching), the major costs are for installing, operating, and
monitoring the treatment plants. In fact, almost 95% of the,, .
cost is associated with these tasks. The reason for the high
operating and monitoring costs is the projected 80 to 100 years
that the treatment plants will have to operate.
6-8
-------
Table 6-3 Summary table - Aquifer restoration costs (DOE 88b)
Option
where:
Cost (Millions $)
Base
Project
Current*
1
2
3
4
5
6
7
8
9
745.68
393.71
538.44
593.60
453.73
745.68
393.71
538.44
593.60
453.73
1,715.07
905.54
1,238.41
1,365.28
1,043.58-
1,061.85
560.65
766.74
845.29
646.11
Number of
Option
Current*
1
2
3
4
5
6
7
8
9
treatment Plant
plants at sampling
Falls City frequency
3
1
3
3
1
3
1
3
3
1
daily
schedule
schedule
schedule
schedule
daily
schedule
schedule
schedule
schedule
A
A
B
B
A
A
B
B
Well
sampling
frequency
daily
schedule
schedule
schedule
schedule
daily
schedule
schedule
schedule
schedule
Project
factor
C
C
C
C
C
C
C
C
2.
2.
2.
2.
2.
1.
1.
1.
1.
1.
3
3
3
3
3
424
424
424
424
424
where schedules are presented in percentage of the restoration
or monitoring time which varies from site to site. For example,
if restoration is estimated to take 10 years, under schedule A
sampling would occur on a daily basis for 1 year, on a 3 day per
week basis for 20 years, on a weekly basis for 3 years, on a
semimonthly basis for 2 years and on a monthly basis for 2 years.
Schedule A
Daily 10%
3 days/week 20%
Weekly 30%
Semimonthly 20%
Monthly 20%
*DOE 88a
Schedule B
Daily 20%
3 days/week 30%
Weekly 20%
Semimonthly 30%
Schedule C
Quarterly 20%
Annually 70%
Quarterly 10%
6-9
-------
Only one treatment plant is needed at Falls City. The
contaminated ground water extends less than three miles and can
be pumped inexpensively to a central treatment plant. Use of
one plant instead of three reduces construction costs from $28
million to $10 million, operating costs from $179 million to $63
million, and monitoring costs from $123 million to $44 million.
Reducing the plant monitoring schedule from daily to monthly
gradually over the 100-year operating period further reduces
monitoring costs from $44 million to $11 million. When the
reduced monitoring schedule is extended to all sites, the low
end of the range of the total base cost estimate is $394 million.
The "project factor" reflects the difference in cost between
industry doing the job and the government (DOE) doing the job.
Although the 1.424 factor appears more reasonable than the 2.3
factor, especially considering the routine nature of the job, it
is not clear that EPA is required to consider this additional
cost in promulgating standards. Basically, the-cost of actively
restoring ground water quality at all 24 sites," according to DOE
estimates, is $394 million. However, DOE has identified 7 sites
that will not require active restoration, This is consistent
with EPA's projection in the draft BID (EPA 87). Reducing the
DOE base cost by the active restoration costs for these 7 sites
results in a total estimated base cost of $325 million. This
cost estimate includes monitoring costs over a period that
extends to 100 years at some sites. This estimate can then be
compared to EPA's cost estimate of $240 million (see Table 6-1
and Section 6.5).
A comparison of DOE and EPA total cost estimates is presented in
Table 6-4. The low estimate from the May 1988 DOE submittal is
used since this appears to be the most reasonable estimate. The
estimated costs for ground-water monitoring at the 7 sites where
cleanup is unlikely are from the November 1988 DOE submittal.
The EPA costs are from Table 6.1. The two estimated total costs
are within about 30% of each other, which is acceptable
agreement, given the preliminary nature of the data.
DOE appears to use unusual conservatism in estimating some of
these costs for ground-water restoration. An example of this is
found in the estimate for the Falls City site. The latest DOE
projection indicates it will take 53 years to restore the ground
water at Falls City using a treatment plant with a capacity of
100,000 gallons per day (DOE 88c). DOE estimates the installed
cost of a treatment plant of this size to be $2 million. With
an assumed plant lifetime of 20 years, 3 new plants are assumed
to be needed over the 53-year restoration period, for a total
installation cost of $6 million. The EPA estimate for the total
installed cost of 3 treatment plants is $1 to $2 million, after
increasing 1975 costs by a factor of 3 to account for inflation
(EPA 77). Operating the treatment plant for 53 years is
estimated by DOE to cost $33 million. This may be compared to
EPA's estimate of operating costs of $11 million (EPA 77). The
6-10
-------
Table 6-4 Comparison of DOE and EPA Cost Estimates
for Restoration of Ground Water at the
Inactive Uranium Mill Tailings Sites
DOE estimates
Site
Ambrosia
Belf ield
Bowman
Canonsburg
Durango
Falls City
Grand Junction
Green River
Gunnison
Lakeview
Lowman
Maybell
Mexican Hat
Monument Valley
Naturita
Rifle - old
Rifle - new
Riverton
Salt Lake City
Shiprock
Slick Rock - NC
Slick Rock - UC
Spook
Tuba City
Totals
Similar Base cost
site (DOE 88b)
Lakeview 25.58
Lakeview
Lakeview
Riverton 8.32
Gunnison 8.50
Falls City 103.02
Riverton 5.98
Lakeview
Gunnison 18.3
Lakeview 9.8
Lakeview
Tuba City 4.7
Tuba City
Tuba City 20.6
Riverton 4.2
Riverton
Riverton 3.93
Riverton 14.53
Riverton
Riverton 6.04
Riverton 3.88
Riverton 4.16
Tuba City 40.92
Tuba City 18.68
301
Monitoring
cost only
(DOE 88c)
2.8
3.8
3.8
2.8
2.8
3.8
3.8
23.6
EPA
cost
estimates
7.74
2.38
5.31
46.71
6.98
20.67
30.51
2.93
33.56
1.95
7.01
10.82
11.77
1.39
1.34
7.48
15.36
214
6-11
-------
primary cause of this difference is due to the size of the
operating crew, estimated as 15 person-days per day by DOE and
as .4 person-days per day by EPA. We do not believe, it is
necessary to maintain a full crew for all three 8-hour shifts.
One is sufficient for two of these, since repairs and manpower
intensive maintenance can be scheduled for a normal daytime
workday shift.
6.8 REVIEW OF TOTAL URANIUM VALUE
An estimate of the total value of the uranium produced at the
inactive sites was made to provide a perspective on the costs of
remediation of ground water contamination. The total quantity
of tailings at the inactive sites is about 25 million tons (see
Chapter 3). The average uranium content of the ore was
estimated to be 0.25%. We were unable to determine the price
actually paid for uranium at these inactive sites. However,
uranium production and prices were summarized by DOE in their
1982 report on commingled uranium tailings (DOE 82). The report
contains data for the licensed, or to be licensed, sites that
were operating during the 1949 through 1971 period, including
the quantity of uranium purchased and the purchase price. Most
of the uranium from these sites was purchased in the 1960s. It
is reasonable to assume that uranium from the inactive sites was
purchased earlier or in any case no later than that from the
licensed sites. Based on this data and assuming a mean year of
production of 1965, the price of the uranium varied over a
narrow range with a mean of about 10 dollars per pound.
Using the above values, it is estimated that the value of
uranium produced at the inactive sites was $1.2 billion 1965
dollars. Using the producer price index for crude materials for
further processing (GPO 89) to escalate this value to the
estimated 1989 value yields $3.9 billion. The estimated present
value of the cost of cleanup of the ground water at the inactive
sites is $214 million, or less than 6% of the total value of the
uranium produced at these sites, in constant dollars.
6.9 REFERENCES
DOE 82 Commingled Uranium Tailings Study, DOE/DP-0011, U.S.
Department of Energy, Washington, D.C. 20545 (June
1982).
DOE 88a U.S. Department of Energy, letter to EPA docket, number
R-87-01, from Theodore J. Garrish, Assistant Secretary
for Nuclear Energy, January 26, 1988.
DOE 88b U.S. Department of Energy, material provided to Tom
Loomis, EPA contractor, entitled "Attachment A,
Re-estimation of Aquifer Restoration Costs, May 17,
1988."
6-12
-------
DOE 88c U.S. Department of Energy, "Final Response to'Standards
for Remedial Actions at Inactive Uranium Processing
Sites," November 1988.
EPA 77 U.S. Environmental Protection Agency, "Costs of Radium
Removal from Potable Water Supplies,"
EPA-600/2-77-073. Municipal Environmental Research
Laboratory, Office of Research and Development, U.S.
EPA, Cincinnati, Ohio 45268.
EPA 86 U.S. Environmental Protection Agency, "RCRA Ground
Water Monitoring Technical Enforcement Guidance
Document (TEGD)," OSWER-9950.1, September 1986.
EPA 87 U.S. Environmental Protection Agency, "Ground-Water
Protection Standards for Inactive Uranium Tailings
Sites - Background Information for Proposed Rule," EPA
520/1-87-014, Office of Radiatio'n Programs, Washington,
D.C. 20460.
GPO 89 Economic Report of the President, U.S. Government
Printing Office, Washington, D.C. (January 1989).
NUREG86 U.S. Nuclear Regulatory Commission, "An Analysis of
Excursions at Selected In Situ Uranium Mines in Wyoming
and Texas," NUREG/CR-3967 (ORNL/TM-9956), 1986.
6-13
-------
-------
CHAPTER 7
OTHER CONSIDERATIONS
7.1 CONCENTRATION LIMITS FOR MOLYBDENUM, URANIUM, RADIUM AND
NITRATES
Molybdenum, uranium, radium and nitrates have been found in
tailings and in ground water that is contaminated by tailings.
While these substances have not been listed as hazardous under
the Resource Conservation and Recovery Act (RCRA), which amended
the Solid Waste Disposal Act (SWDA), they have been identified
as hazardous or controlled in other EPA rules using different
authorities. However, quantitative limits that are useful for
this rulemaking have not, as yet, been determined for uranium
and molybdenum. The proposed concentration limits for each of
these four substances are discussed in this section.
7.1.1 Molybdenum
Molybdenum was added to the hazardous constituents for the
licensed tailings since it was found in high concentrations at
some sites and had caused molybdenosis in cattle (48FR45926,
Do72). No concentration limit was established at that time,
however, because only sparse data were available on human
toxicity. Listing molybdenum, but not issuing a concentration
limit, means it must be controlled to background levels, to be
consistent with RCRA standards.
A concentration limit of 50 ppb was proposed for molybdenum
in the proposed standards for inactive tailings (46FR2556).
This proposed groundwater standard was not promulgated, however,
because as stated in the Federal Register notice, "We do not
believe that the existing evidence indicates that ground water
contamination from inactive mill tailings is or will be a matter
of regulatory concern" (48FR590). The Court remanded this to
the Agency in 1985.
The Agency has proposed National Primary Drinking Water
Regulations for Inorganic Chemicals, among others (50FR46936).
While the Agency decided not to propose a Recommended Maximum
Concentration Limit (RMCL) [This is now being called a Maximum
Concentration Limit Goal (MCLG).] for molybdenum because of
inadequate data on toxicity of the compound, a provisional
adjusted acceptable daily intake (AADI) was determined. This
provisional AADI was based upon an epidemiological study in
which only one dose was examined and no effects were noted.
7-1
-------
The Agency asked for comments on the question, "Should a Health
Advisory be developed for molybdenum or is there sufficient
health effects information upon which to base an RMCL?" While
the Agency has not made a final decision on molybdenum, it
appears unlikely that a Health Advisory will be issued for
molybdenum based on the NAS consideration (NAS80) that
molybdenum in drinking water, except from highly contaminated
sources (molybdenum mining waste water), is not likely to
constitute a significant portion of the total human daily intake
of the element.
An analysis of toxic substances in tailings was included in the
Final EIS for Remedial Action Standards for Inactive Uranium
Processing Sites (EPA82), Appendix C. This analysis included
consideration of molybdenum in tailings and of molybdenum
toxicity in humans, livestock, and crops.
Molybdenum in tailings is found at levels greater than 100 times
its levels in typical or local soils. Uranium, selenium,
arsenic, and vanadium are the only other metallic elements found
at similarly high levels. However, data show wide variations of
element concentrations among different piles. The ratio of an
element's concentration in tailings to that in the spil
surrounding the tailings is a measure of both its potential
hazard and its potential for contaminating ground water.
Molybdenum is essential in trace quantities for human
nutrition. There are no data for acute toxicity of molybdenum
following ingestion by humans, but the animal data (Ve78) show
that toxicity results from intakes of around hundreds of
milligrams per kilogram of body weight.
Chronic toxicity symptoms have been reported in 18 percent to 31
percent of a group of Armenian adults who consumed 10 to 15
milligrams of molybdenum per day and in 1 percent to 4 percent
,of a group consuming 1 to 2 milligrams of molybdenum per day
(Cha79), (NAS80). Clinical signs of the toxicity were a high
incidence of a gout-like disease with arthralgia and joint
deformities, and increased urinary excretion of copper and uric
acid. Increased urinary copper excretion has been observed in
persons who consumed 0.5 to 1.5 milligrams of molybdenum per day
and in persons drinking water containing 0.15 to 0.20 ppm of
molybdenum but not in persons drinking water containing up to
0.05 ppm of molybdenum (Cha79). The significance of the
increased copper excretion is not known. Recent reports have
associated molybdenum deficiency and esophageal cancer
(Lu80a,b). Until these reports are confirmed and evaluated, the
minimum molybdenum requirements are uncertain.
7-2
-------
The ratio of toxic intake to the recommended daily allowance for
humans is narrow for molybdenum, ranging from 10 to 40 (NAS80).
Using the NAS80 value for Adequate and Safe Daily Intake of 0.15
to 0.50 mg and this ratio leads to an estimated potentially
toxic daily intake of 2 to 20 mg of molybdenum,
In livestock,
toxicity were
most critical
dairy cattle,
lactating cows
water that is
,ppm (EPA82).
molybdenum in
estimates of molybdenum concentrations leading to
made for both ruminants and nonruminants. The
receptor for molybdenum in the water pathway was
because of the large water consumption of
The estimated concentration of molybdenum in
potentially toxic to dairy cattle is 0.51 to 2.6
This led to a recommended maximum concentration of
water of 0.05 ppm (EPA82).
In crops, estimates were made of molybdenum concentrations in
irrigation water that might be toxic to agricultural crops grown
using such water. Based on an NAS publication (NAS72),
irrigation water at 1 ppm molybdenum could be immediately toxic
to crops if the irrigation water is applied at 3-acre foot per
acre per year (8.13 Ibs of molybdenum per acre per year).
7.1.2 Uranium
The National Interim Primary Drinking Water Regulation
(40CFR141, EPA76) provide no maximum contaminant level (MCL) for
uranium. In fact, uranium along with radon is explicitly
excluded from the MCL for gross alpha particle activity
(40CFR141) which is 15 pCi per liter. These were excluded
because data were inadequate to determine if there was a need
for such regulations (i.e., the levels of uranium and radon in
water were not well-known) and the cost of removal of uranium
and radon from drinking water was not established. The Agency
has issued an advance notice of proposed rulemaking (51FR34836)
stating that MCLGs and MCLs are being considered for radium-226,
-228, natural uranium, radon, gross alpha, and gross beta and
photon emitters.
At the uranium mill tailings sites, natural uranium is present
and consists of three isotopes, 234U, 0.0057% abundance by
weight; 235U, 0.7196% abundance; and 238g, 99.276%
abundance. Their half-lives are, respectively, 2.47 x 105
years, 7.1 x 108 years, and 4.51 x 109 years. Each decays
by emitting an alpha particle; uranium-234 and 235 also emit
gamma rays. Although uranium-238 is the most abundant isotope
in natural uranium by weight, it accounts for only half of the
total radioactivity of natural uranium.
7-3
-------
Uranium can damage human health two ways, chemically and
radiologically. Uranium ingested above ,a certain concentration
is chemically toxic to humans and thus has a threshold below
which chemical toxicity does not exist. The National Academy of
Sciences (NAS 83) reviewed the toxicity level of uranium and
issued a suggested No-Adverse-Response, Level (SNARL) of 35 ppb
(23 pCi/1) for chronic exposure. The NAS report states,,
"Because of its low specific activity, natural uranium dose'not
pose a problem of radiotoxicity in drinking water. Assessment
of uranium toxicity in drinking water should be based on its
chemical toxicity and not on radiation toxicity. However, when
the specific activity of uranium in drinking water has been
altered so that it is greater than that of natural uranium,
potential radiotoxicity should be given, attention equal to that
of the chemical toxicity. The committee also recommends that
toxicological assessment of uranium in water be based solely on
its renal toxicity in all instances except when industrial
processes result in., a marked enrichment of shorter-lived uranium
isotopes."
Radiotoxcity can be the basis for establishing a limit for
uranium in drinking water by using the recommendations of the
International Commission on Radiological Protection (ICRP 78).
By allowing the same level of risk for uranium as for radium
(0.7 to 3.0 fatal cancers per year per million persons exposed)
a natural uranium concentration limit of 23 pCi/1 is calculated
by using ratios of the ICRP annual limits on intake (ALIs) for
stochastic (non-threshold) effects. Using the ICRP ALIs for
nonstochastic (toxic) effects^ for protection of workers yields a
natural uranium concentration limit of 30 pCi/1, assuming the
same risk from uranium as from radium. This approach, therefore
leads to limits for natural uranium in .drinking wate.r that are,
for all practical purposes the same as the NAS recommended
limits.
, ' ' ' < - • : '
A review of the uranium concentrations in ground water at the 14
sites for which data are available (see Chapter 4) is presented
in Table 7.1. This review indicates that when uranium
contamination of ground water occurs at uranium mill sites
con'centrations of uranium increase substantially. Large
percentages of the ground water samples that were measured for
uranium exceed 100 pCi/1 at most sites. Based on these limited
data, ground water is contaminated at 12 of the 14 sites at
either the 30 pCi/1 or the 100 pCi/1 limit. From this it can be
concluded that the choice of a limit in the range under
consideration (10 to 100 pCi/1) will not make a difference in
determining whether or not ground water is contaminated at a
site. However, the choice of a limit may make a difference in
the extent of cleanup-of ground water, should cleanup be
necessary.
7-4
-------
Table 7.1 Summary of Uranium Concentrations in
Ground Water at Inactive Uranium
Mill Tailing Sites
Site
Ambrosia Lake
Canonsburg
Durango
Grand Junction
Green.River
Gunnison
Lakeview
Number of Samples
Analyzed for Uranium (a)
30
55
64
140
156
59
70
Percent of Samples Greater Than
15 ppb (b) 44 ppb 150 ppb
Mexican Hat
Monument Valley
Rifle
Riverton
Salt Lake City
Shiprock
Tuba City
15
57
34
26
81
19
15
77
49
78
79
47
64
4
53
18
94
92
51
95
100
60
40
45
74
37
42
1
47
0
82
88
37
79
87
47
35
20
31
30
32
1
40
0
47
73
21
68
53
(a) For some sites samples are from both down gradient
and background aquifers. For other sites samples are
from known contaminated ground water. No conclusions
should be drawn from these data regarding the need for
cleanup.
(b) 1.47 ppb = 0.00147 mg/1 = 1 pCi/1
7-5
-------
7.1.3 Radium
Radium is present in mill tailings at levels in the hundreds of
pCi per gram range and has been found in elevated concentrations
in ground water near tailings sites. The National Interim
Primary Drinking Water Regulation for radium is 5 PCi per liter
combined radium-226 and radium-228. Since the standards are
required by UMTRCA to be consistent with RCRA standards and
since RCRA standards have adopted drinking water regulations as
standards for ground water, the same procedure is used in this
rulemaking. Thus, the standard for radium is 5 pCi per liter
combined radium-226 and radium-228.
7.1.4 Nitrates
Nitrates have been found in elevated concentrations in ground
water near tailings piles. The National Interim Primary
Drinking Water Regulation for nitrates is 10 mg per liter as
nitrogen. Using the same rationale as above for radium, the
standard for nitrates is 10 mg per liter as nitrogen.
7.2 INSTITUTIONAL CONTROL
The Agency has been considering institutional control for over
ten years. Public workshops and a public forum were conducted
in 1977 and 1978 to develop insight for the objectives of
radioactive waste disposal (EPA77a, EPA77b, EPA78). These
efforts resulted in 1978 with the publication of proposed
Criteria for Radioactive Wastes: Recommendations for Federal
Radiation Guidance (43 F.R. 53262). The subject of
institutional control was a major factor in these
recommendations:
"Proposed Criterion No. 2. The fundamental goal for controlling
any type of radioactive waste should be complete isolation over
its hazardous lifetime. Controls which are based on
institutional functions should not be relied upon for longer
than 100 years to provide such isolation; .radioactive wastes
with a hazardous lifetime longer than 100 years should be
controlled by as many engineered and natural barriers as are
necessary." And,
"Proposed Criterion No. 6. Certain additional procedures and
techniques should also be applied to waste disposal systems
which otherwise satisfy these criteria if use of these
additional procedures and techniques provide a net improvement
in environmental and public health protection. Among these
are: a. Procedures or techniques designed to enhance the
retrievability of the waste; and b. Passive methods of
7-6
-------
communicating to future people the potential hazards which could
result from an accidental or intentional disturbance of disposed
radioactive wastes."
These proposed criteria were further discussed:
"Issue No. 2. Control of Radioactive waste. The management of
radioactive wastes represents potential exposure of individuals
and populations and the possible contamination of the general
environment. These potential impacts require definitive
controls to be established. Further, because of the trustee
responsibility each generation has to succeeding ones,
contamination of the general environment should be avoided
regardless of whether humans will actually contact the waste
directly. It is important to prevent both human and
environmental adverse impacts. Therefore, the fundamental goal
for controlling any type of radioactive waste should be complete
isolation over its hazardous lifetime.
"Controls for radioactive wastes are of three general types:
Engineered barriers, natural barriers, and institutional
mechanisms. Engineered barriers such as containers or
structures generally can be considered only as interim measures
for containment, despite the fact that some structures have
survived intact through the ages. Stable geologic media are an
example of natural barriers. Institutional controls are those
which depend on some social order to prevent humans from coming
in contact with wastes, such as controlling site boundaries,
guarding a structure, land use policies, record-keeping,
monitoring, etc.
"It generally is accepted that long-term isolation should depend
on stable natural barriers. Institutional mechanisms, which are
essential in the early stages of management of any waste, are
short-term processes because of practical limitations.
Institutional means can be very effective i-n isolating
radioactive wastes from humans if they can be maintained. Since
society's basic structure and concern about waste may change, it
is reasonable to rely on such controls for only limited periods.
"The choice of a time period for relying on institutional
control is completely a matter of judgment, but is basic to a
determination of when use of such controls is proper. During
the developmental stages of this criteria document, it was
proposed that 100 years should be the maximum time period for
such controls to be depended upon with any degree of assurance.
The public forum participants recommended deleting the time
period because it appeared to be arbitrary; however, they left
the issue unaddressed in any other form.
7-7
-------
"Because there are a number of current mechanisms for disposing
of various types of wastes which are based on institutional
care/ the Agency believes that guidance is required to assure
that institutional controls are relied upon only ,to the extent
they are appropriate. There are numerous types of radioactive
wastes of such hazard potential that they will require the
adoption of stricter control methods than currently practiced
and will require the development of new disposal technologies
which will assure better isolation [than] that afforded by
institutional control mechanisms. For this reason, when
disposal decisions are made they should recognize that
institutional controls are only of limited use, and if the
wastes will be hazardous longer than 100 years, other means of
control will need to be found.
"This means that in selecting control options for wastes whose
hazards extend beyond 100 years decisions makers cannot rely on
restrictions on customary uses of land and of ground or surface
waters. This does not mean that institutional controls are
required for 100 years, or that they must stop at that point if
society can still maintain them; only that people making the
initial disposal decision should not plan on their use to
maintain protection beyond 100 years. The judgment that 100
years is the most appropriate time interval will be further
examined throughout the public comment period."
"Issue No. 6 Supplementary Protection Goals. A number of
other subjects pertinent to protection of the public from
radioactive wastes were discussed in the development of the
criteria. Among> these, most attention centered on monitoring,
provision of ret'rievability, and passive communication of the
nature of the possible hazard to future generations. In
general, it was,determined that, while each has positive aspects
for control of radiological hazards, their application might
undermine the goal of providing permanent isolation for wastes.
It is difficult to maintain retrievability or conduct a
monitoring program without compromising the ability to provide
isolation. Furthermore, in many disposal situations which will
satisfy the five criteria discussed above, the residual risk
will mainly be attributable to potential failure mechanisms
involving eventual intrusion by humans. Passive methods of
communicating the hazard, such as markers which call attention
to the waste, may sometimes be judged to provide a net reduction
of risk. Other passive methods, such as creating records
describing the waste, or setting aside of the land title to the
disposal site, have value in reducing the likelihood of
intrusion for some limited time.
"An example of a circumstance where land title transfer is
reasonable is a current site that has been in use for some time
where optimal environmental isolation is no longer a practicable
7-8
-------
alternative, such as an abandoned mill tailings site, a nuclear
test facility site, etc. In these cases, Federal ownership of
the land beyond the normal period of institutional control would
be reasonable to minimize potential intrusion. Such decisions
should be made on a case-by-case basis and provision for
specifically treating such exceptions should be addressed in
standards and regulations which are promulgated for these types
of wastes.
"It is not appropriate to depend upon methods such as these or
other similar ones for long-term control; nonetheless, when such
methods would enhance overall protection from wastes, it is
prudent to use them. This is particularly the case for
retrievability and passive communication. Monitoring was judged
by the Public Forum participants to be generally a part of early
institutional controls prior to completion of disposal, and thus
it is not included in the criterion for supplementary controls."
While these criteria were never enacted in final form, they
served as the basis for the assurance requirements (40 CFR
191.14) which the Agency issued as final standards in 1985:
Environmental Standards for the Management and Disposal of Spent
Nuclear Fuel, High-Level and Transuranic Radioactive Wastes 50
F.R. 38066. These standards culminated the above consideration
of institutional control in this context. Specifically:
40 CFR 191.14 (a) Active institutional controls over
disposal sites should be maintained for as long a
period of time as is practicable after disposal;
however, performance assessments that assess isolation
of the wastes from the accessible environment shall
not consider any contributions from active
institutional controls for more than 100 years after
disposal.
(b) Disposal systems shall be monitored after disposal
to detect substantial and detrimental deviations from
expected performance. This monitoring shall be done
with techniques that do not jeopardize the isolation
of the wastes and shall be conducted until there are
no significant concerns to be addressed by further
monitoring.
(c) Disposal sites shall be designated by the most
permanent markers, records, and other passive
institutional controls practicable to indicate the
dangers of the wastes and their location.
Where the following terms are defined as:
7-9
-------
40 CPR 191.12 (a) "Disposal system" means any combination
of engineered and natural barriers that isolate spent
nuclear fuel or radioactive waste after disposal.
(d) "Barrier" means any material or structure that
prevents or substantially delays movement of water or
radionuclides toward the accessible environment. For
example/ a barrier may be a geologic structure, a
canister, a waste form with physical and chemical
characteristics that significantly decrease the
mobility of radionuclides, or a material placed over
and around waste, provided that the material or
structure substantially delays movement of water or
radionuclides.
(e) "Passive institutional control" means: (1)
Permanent markers placed at a disposal site, (2)
public records and archives, (3) government ownership
and regulations regarding land or resource use, and
(4) other methods of preserving knowledge about the
location, design, and contents of a disposal system.
(f) "Active institutional control" means: (1)
Controlling access to a disposal site by any means
other than passive institutional controls; (2)
performing maintenance operations or remedial actions
at a site, (3) controlling or cleaning up releases
from a site, or (4) monitoring parameters related to
disposal system performance.
And the following guidance for implementation is given:
40 CFR 191 Appendix B Institutional Controls. To
comply with section 191.14(a), the implementing
agency will assume that none of the active
institutional controls prevent or reduce
radionuclide releases for more than 100 years
after disposal. However, the Federal Government
is committed to retaining ownership of all
disposal sites for spent nuclear fuel and
high-level and transuranic radioactive wastes and
will establish appropriate markers and records,
consistent with section 191.14(c). The Agency
assumes that, as long as such passive
institutional controls endure and are understood,
they: (1) can be effective in deterring
systematic or persistent exploitation of these
disposal sites; and (2) can reduce the likelihood
of inadvertent, intermittent human intrusion to a
degree to be determined by the implementing
7-10
-------
agency. However, the Agency believes that passive
institutional controls can never be assumed to
eliminate the chance of inadvertent and intermittent
human intrusion into these disposal sites.
The statement of considerations for this regulation (50 F.R.
38066) includes the following discussion:
"Approach Toward Institutional Controls. The Agency
particularly sought comment on its proposed approach to reliance
on institutional controls. The proposed rule limited reliance
on 'active institutional controls' (such as controlling access
to a disposal site, performing maintenance operations, or
cleaning up releases) to a reasonable period of time after
disposal, described as on the order of a 'few hundred years.'
On the other hand, 'passive institutional controls' (such as
permanent markers, records, archives, and other methods of
preserving knowledge) were considered to be at least partially
effective for a longer period of time.
"Pew commenters argued with the distinction between active and
passive institutional controls, or with the amount of reliance
the proposed rule envisioned for passive controls. However,
many commenters felt that 'a few hundred years' was too long a
period to count on active controls. Accordingly, the final rule
limits reliance on active institutional controls to no more than
100 years after disposal. This was the time period the Agency
considered in criteria for radioactive waste disposal that were
proposed for public comment in 1978 (43 P.R. 53262), a period
that was generally supported by the commenters on that
proposal. After this time, no contribution from any of the
active institutional controls can be projected to prevent or
limit potential releases of waste from a disposal system.
"The concept of passive institutional controls has now been
incorporated into the definition of 'controlled area' that is
used to establish one of the boundaries for applicability of the
containment requirements and the individual protection
requirements in the final rule. Because the assumptions made
about the effectiveness of passive institutional controls can
strongly affect implementation of the containment requirements,
the Agency's intent has been elaborated in the "guidance for
implementation" section. The Federal Government is committed to
retaining control over disposal sites for these wastes as long
as possible. Accordingly (and in compliance with one of the
assurance requirements), an extensive system of explanatory
markers and records will be instituted to warn future
7-11
-------
generations about the location and dangers of these wastes.
These passive controls have not been assumed to prevent all
possibilities of inadvertent human intrusion, because there will
always be a realistic chance that some individuals will over
look or misunderstand the markers and records. (For example,
exploratory drilling operations occasionally intrude into areas
that clearly would have been avoided if existing information had
been obtained and properly evaluated.) However, the Agency
assumed that society in general will retain knowledge about
these wastes and that future societies should be able to deter
systematic or persistent exploitation of a disposal site.
"The Agency also assumed that passive institutional controls
should reduce the chance of inadvertent intrusion compared to
the likelihood if no markers and records were in place.
Specific judgments about the chances and consequences of
intrusion should be made by the implementing agencies when more
information about particular disposal sites'and passive control
systems is available. The parameters described in the "guidance
for implementation" represent the most severe assumptions that
the Agency believed were reasonable to use in its analyses to •
evaluate the feasibility of compliance with this rule (analyses
that are summarized in the BID). The implementing agencies are
free to use other assumption if they develop information
considered adequate to support those judgments.
"The role envisioned for institutional controls in this •
rulemaking has been adapted from the general approach the Agency
has followed in its activities involving disposal of radioactive
wastes since the initial public workshops conducted in 1977 and
1978. The Agency's overall objective has been to protect public
health and the environment from disposal of "radioactive wastes
without relying upon institutional controls for extended periods
of time—because such controls do not appear to be reliable
enough over the very long periods that these wastes remain
dangerous. Instead the Agency has pursued standards that call
for isolation of the wastes through the physical characteristics
of disposal system siting and design, rather than through
continuing maintenance 'and surveillance. The principle was
enunciated in the general criteria published for public comment
in 1978 (43 F.R. 53262), and it has been incorporated into the
Agency's standards for disposal of uranium mill tailings (48
F.R. 590, 48 F.R. 45926).
"This approach has been tailored to fit two circumstances
associated with mined geologic repositories. First, 40 CFR Part
191 places containment requirements on a broad range of
7-12
-------
potential unplanned releases as well as the expected behavior of
the disposal system. Therefore, determining compliance with the
standards involves performance assessments that consider the
probabilities and consequences of a variety of disruptive
events, including potential human intrusion. Not allowing
passive institutional controls to be taken into account to some
degree when estimating the consequences of inadvertent human
intrusion could lead to less protective geologic media being
selected for repository sites. The Agency's analyses indicate
that repositories in salt formations have particularly good
capabilities to isolate the wastes from flowing groundwater and,
hence, the accessible environment. However, salt formations are
also relatively easy to mine and are often associated with other
types of resources. If performance assessments had to assume
that future societies will have no way to ever recognize and
limit the consequences of inadvertent intrusion Jfrom solution
mining of salt, for example), the scenarios that would have to
be studied would be more likely to eliminate salt media from
consideration than other rock types. Yet this c.ould rule out
repositories that may provide the best isolation, compared to
other alternatives, if less pessimistic assumptions about
survival of knowledge were made.
"The second circumstance that the Agency considered in
evaluating the approach towards institutional controls taken in
this rule is the fact that the mined geologic repositories
planned for disposal of the materials covered by 40 CFR Part 191
are different from the disposal systems envisioned for any other
type of waste. The types of inadvertent human activities that
could lead to significant radiation exposures or releases of
material from geologic repositories appear to call for much more
intensive and organized effort than those which could cause
problems at, for example, an unattended surface disposal site. ..
It appears reasonable to assume that information regarding the
disposal system is more likely to reach (and presumably deter).
people undertaking such organized efforts than it is to inform
individuals involved in mundane activities.
"These considerations led the Agency to conclude that a limited
role for passive institutional controls would be appropriate
when projecting the long-term performance of mined geologic
repositories to judge compliance with these standards."
7-13
-------
The Agency is continuing its consideration of institutional
control with emphasis on its effectiveness. There is a need for
guidance on the role for institutional control in developing
corrective action policies for Subtitles C and D under the
Resource Conservation and Recovery Act (RCRA), in designing the
alternate concentration limit (ACL) program under RCRA, and in
developing policies and achieving consistency for Superfund,
especially in view of the Superfund Amendments and
Reauthorization Act of 1986 (SARA).
Institutional controls can be ranked in terms of their
effectiveness although it must be recognized that such ordering
is not objective. There are many shifting perceptions about the
effectiveness of each control, most of which are based on
societal behavior. Nevertheless, the following ranking of
institutional controls in roughly decreasing order of
reliability may be useful in a broad, albeit arbitrary, context:
Monument (marble, granite, etc.)
Security program (guards and fences)
Government ownership
Government controlled easements on property
adjacent to government-owned property
Restrictive covenant (deed restriction)
Deed notice
Professional licensing (licensing of well
drillers)
Permitting programs (well construction
permits)
Environmental standards (for well
construction and location)
Water quality testing
Zoning (regulation of new development and
property transactions)
Health advisories
7-14
-------
The institutional controls with the greatest effectiveness are
permanent and attention-gathering monuments, a security program
involving guards, fences, etc., and government ownership.
The second group involves land records and includes easements,
deed restrictions, and deed notices. This second group is
considered more effective than the third group since it involves
less human activity and what human activity it does entail is
primarily performed early (soon after a decision is made to use
institutional controls). The third group includes
regulatory/licensing actions similar to those applied to
regulated operating activities. This third group involves more
human activity than the second group. The fourth group involves
a variety of general controls which are considered the least
effective of this list. • • •
There are three important points evident in this ranking.
First, some of the institutional controls are active in that
continuing actions are required by persons and some are passive
in that no continuing actions are required by persons. Since
active institutional controls are effective only as long as
persons take action, selecting the period over which they retain
effectiveness is crucial for health and environmental protection,
This timing question became the focus of the Agency's
considerations of institutional control for providing protection
from radioactive waste. There is no general consensus off the^-
length of time human institutions will remain effective s^.-^^
reliable to continue such active measures. In this regard,
failure of institutional controls does not necessarily imply a
complete breakdown of societal structure. The more likely
situation would be failure of institutional controls through
program reductions, reorganization, changes in priorities, or^ ,
through the failure of special funding mechanisms. .-- " -- "~
The timing question is most applicable to hazardous^onstituents
at uranium mill sites since metals are the primary p'roblem and
no radioactive decay or organic decomposition takes place with
metals. Dispersion of the metals in the ground water or
adsorption in the aquifer matrix are the only natural cleansing
processes.
Second, certain active institutional controls can be effective
for as long as they last. A security program, for example,
might well be the best institutional control method available
for a short period. As such, active controls may be the best
solution at a contaminated ground water site, if predictions of
ground water cleansing by natural processes reliably project
decontamination within a period during which the active "
institutional controls are highly effective. Another benefi-fe—©€-
7-15
-------
this approach is a reduction in both economic and environmental
costs. An active institutional control solution is generally
less expensive than a restoration program. Further, less
environmental harm results from an active institutional control
than from restoration activities. Restoration of ground water
uses considerable energy and can contaminate large land areas
for impoundments, processing plants, and associated
appurtenances.
Third, institutional controls can be considered voluntary or
involuntary, based on whether people comply with controls on
their own accord or are forced to comply. A permanent marker is
considered a voluntary control since it indicates the presence
of hazardous wastes at a site but does not restrict actions
which might disturb such wastes. A security program is
considered an involuntary control since guards would prevent
people from intruding into such wastes. Controls -that prohibit
new well construction or that prevent certain uses of the land
can be voluntary or involuntary depending 'on the statutory
authorities and implementing philosophy or practice of the local
or state agency.
Institutional controls may be useful when combined with limited
restoration of ground water quality. As discussed in Chapter 6,
most of the decontamination appears to be achieved in the early
stages of ground water pumping. If this initial efficiency of
pumping is found to be the general case or can be reliably
predicted, it may be feasible to combine limited pumping with
institutional controls. This could be especially attractive if
the initial pumping can reduce contaminant concentrations to
levels where natural cleansing will reduce concentrations to
standards levels within the life time of institutional controls,
Since wide variations exist in contamination and site
characteristics and since local and state laws vary with regards
to institutional control mechanisms, it is difficult to develop
a generally applicable limit for a combined cleanup and
institutional control effort. Nevertheless, it might be
possible to establish a concentration, limit at a particular site
that is a few times the MCL and at which consideration of
institutional control is warranted.
7-16
-------
7.3 POST-REMEDIATION GROUNDWATER CONTAMINATION
Existing plumes of contaminated groundwater have been
identified and evaluated at the various sites. These plumes
have been characterized and estimates made as to both the time
frame and efficacy of natural flushing to reduce the various
contaminates to acceptable levels, either MCLs or, in some
cases, background levels. Where it did not appear that these
levels would be attained through natural flushing, estimates
were made of the time and costs for alternative treatment of
the contaminated groundwater. These estimates are presented
elsewhere in this BID.
Following stabilization of the piles there are three possible
mechanisms by which the tailings may serve as sources of new or
continued contamination of the local groundwater: seasonal
intrusions of local groundwater into the tailings piles,
seepage of precipitation through the cover and*the tailings,
and drainage of moisture added during the remediation
construction process to aid in tailings compaction during
consolidation, relocating, and/or regrading of-the piles. As
discussed below, infiltration or seepage of precipitation into
and through the tailings has been identified as the most
serious long-term groundwater concern at the Title I UMTRA
sites and designs for the pile covers are being evaluated on a
site-specific basis to address this possibility.
7.3.1 Groundwater Intrusion
Studies identified groundwater intrusion as a potential problem
at three sites: Grand Junction, Riverton, and Salt Lake City.
The tailings have been relocated from the Salt Lake City site
to Clive, the tailings at Riverton are in the process of being
relocated to a Title II site, and it is planned to move the
Grand Junction tailings to Cheney Reservoir site. Relocation
of the tailings and contaminated soils will eliminate the
source of contamination at the original site; care is taken in
selection of alternate disposal sites and design of the
disposal cells to avoid this problem at the new sites.(Ca88)
Groundwater intrusion is not considered to be a possibility at
the sites identified for stabilization-in-place (SIP) or
stabilization-on-site (SOS). At the SIP sites it has been
determined that the base of the existing tailings pile is above
the fluctuation range of the water table. At the SOS sites,
where some or all of the tailings are to be relocated on the
site, designs call for the tailings to be sited so that the
base of the pile will be above the water table fluctuation
range.
7-17
-------
7.3.2 Precipitation
Precipitation which lands on the pile may infiltrate through
the cover and the tailings, leaching contaminants from the
tailings and carrying them into the groundwater thus augmenting
groundwater contamination. Even though the average annual
precipitation exceeds the average annual evaporation at all of
the sites except Canonsburg, this has been identified as a
concern because of the rock erosion barrier capping the piles.
It appears 'that the unvegetated riprap or broken rock layer
capping the pile and armoring the sides to prevent erosion will
significantly reduce evaporation, allowing more infiltration.
Field studies carried out on completed piles at Clive and
Shiprock, both sites having precipitation of about 6 inches
annually, indicated that these piles are operating under
unsaturated conditions. Measurement showed the compacted clay
radon barrier to be operating at a hydrologic transmissivity in
excess of 10~9 rather than the designed 10~7. Measured
conductivity ranged between 10~9 to 10~12 at Shiprock and
1Q-10 to 10~14 at Clive. At the Burrell vicinity property
near Canonsburg, moisture levels remain at construction levels
and the pile may be operating under saturated conditions with a
hydrologic conductivity of 10~7 for the clay radon barrier.
Additional field studies of the hydrologic conductivity of the
clay layer are to be made at sites having precipitation of 10
to 16 inches annually.(Ti88)
7.3.3 Construction Water
During remediation work some water is added to the tailings and
contaminated soil to control dust and assist compaction and
grading as the tailings are consolidated on site or moved to
another site. Subsequently, most of this added water will
drain from the tailings carrying leached contaminants with it.
This discharge«of contaminated water will be a one-time "slug"
occurring during and for a period after construction
activities.
7.3.4 Construction of Final Cover
Originally, the pile cover was designed principally as a radon
barrier, to control erosion, and to deter intrusion by
vegetation and burrowing animals. Typical cover designs, shown
in Figure 7.1, included a compacted clay and silt radon
barrier, a sand bedding layer, and rock erosion barrier. The
low-permeability radon barrier also served to limit significant
infiltration. Pile covers similar to this design were
installed at Shiprock, Clive, and Canonsburg and planned for
Ambrosia Lake. Prior to publication of the EPA's proposed
groundwater standards, similar pile and cover designs were
7-18
-------
Pool
Starter Dike
BEFORE RECLAMATION
Erosion Barrier
Radon
Barrier
A'
Windblown Contaminated Soils
Windblown Soils
AFTER RECLAMATION (Section A-A')
V-2' Erosion Barrier
• Durable Rock
6" Bedding • Clean Sand
3' Radon Barrier
• Compacted Clay
& Silt
Tailings
• Sand, Silt, & Clay
COVER DETAIL
Original Perimeter of Pile - Tailings
Relocated to Fill Pond Area
PLAN LAYOUT
FIGURE 7-1
TYPICAL UMTRA PROJECT PILE LAYOUT
7-19
-------
being considered for most of the other UMTRA Project sites.
Construction had begun at Lakeview and Durango and was
scheduled for Tuba City and Mexican Hat. Project designs were
significantly advanced at Grand Junction, Belfield and Bowman,
Palls City, and Slick Rock.
As a result of the EPA's proposed groundwater standards the DOE
decided to relocate the tailings from the Monument Valley site
to the Mexican Hat site; it was determined to be more
economical to move the tailings than to stabilize them at
Monument Valley. Also, the proposed standards have had a
significant impact on the decision to relocate the Gunnison
tailings to the Landfill site.
DOE has conducted a technology development program in
conjunction with the UMTRA Project to develop standard
practices for use in carrying, out stabilization of the tailing
piles. A number of special studies were undertaken as a
consequence of the proposed groundwater standards, and
revisions in the disposal pile and cover designs are under
consideration. The studies focused on the use of geomembranes,
alternate cover materials, alternate cover designs (including
both composition and configuration), and disposal cell
configuration. Figure 7.2 illustrates the various cover
components now under consideration for use as appropriate on a
site-by-site basis.
The following is a brief summary of the impact of the proposed
groundwater standards on the various UMTRA Project sites.
-Ambrosia Lake: The hydraulic conductivity of the filter
has been increased; no significant cost increase,,
-Belfield/Bowman: Cover thickness has been increased to
provide frost protection at a cost of about $400,000.
-Canonsburg: No impact; stabilization completed,
-Durango: Significant change in cover design.
-Falls City: Detailed evaluations have not been
completed but it is expected that significant cell and
cover design changes will be required to achieve
compliance with the proposed groundwater standards.
-Grand Junction: New cover design formulated.
-Green River: Cover design modified by adding a frost
protection layer and a higher permeability filter, and
adding sodium bentonite to the radon/infiltration barrier
to reduce permeability. Estimated additional cost is
about $100,000.
7-20
-------
X
c_
UJ
o
cc
t-
UJ
UJ
0.
CO
o
GC
VEGETATION
0-1.0' ROCK MULCH
3.0' GROWTH MEDIUM & FROST PROTECTION
1.0'
0.5'
BIOBARRIER: COBBLES (TOP CHOKED OR
FILTERED)
DRAIN: CLEAN SAND
INFILTRATION BARRIER: CLAYMAX
1.0' RADON BARRIER: CLAY/SILT
FIGURE 7-2
"CHECKLIST"
TOP COVER
7-21
-------
-Gunnison: Tailings to be relocated to new site where
the constrained cell with very low permeability cover
will be constructed.
-Maybelle: Evaluation of design changes required to meet
proposed standards has not been made; some changes in
cover design may be needed.
-Mexican Hat: Material from Monument Valley will be
incorporated at this site.
-Monument Valley:
Hat site.
Tailings to be relocated to Mexican
-Lakeview: No significant changes.
-Lowman: A frost protection layer may be added at a cost
of $100,000.
-Naturita:
adopted.
The constrained cell design will probably be
-Riverton: No effect; the tailings are being relocated
to a Title II facility.
-Rifle: A frost protection layer will be added to the
cover at an estimated cost of $2 million.
-Salt Lake City: No impact; stabilization nearly
complete at time proposed standards published.
-Shiprock: No impact; stabilization' completed.
-Slick Rock: Detailed design reevaluations have not been
done but a frost protection layer will probably have to
be added; estimated cost is $125,000.
-Spook: A layer of CLAYMAX may be placed over the pile
to facilitate demonstrating that ACLs are not required.
-Tuba City: The infiltration barrier will be placed at
an hydraulic conductivity of 10~^; on-site tests show
that this is feasible.
The most significant impact on disposal cell design at
individual UMTRA Project sites has been on the cover design;
the realization that it is imperative to protect the
infiltration barrier from the freeze/thaw cycle to maintain its
low permeability and its ability to comply over the long-term
with the EPA's proposed groundwater standards. The estimated
total cost increase for adding frost protection is about $10
million.
7-22
-------
Relocation of the Monument Valley tailings will cost about $10
million more than the previous design for stabilization on site.
The revised cover designs at Durango, Grand Junction, Gunnison,
Falls City, and Maybelle are roughly estimated to add about $1
million to the stabilization costs at each site.(Ca88)
7.4 REFERENCES
Ca88 Caldwell, J. A., R. Rager and N.B. Larson, "The Impact
of Proposed EPA Groundwater Standards on UMTRA Project
Disposal Cell Design," DOE Remedial Action Program
Annual Meeting, Oct. 18-28, 1988.
Cha79 Chappell, W. R., et. al., "Human Health Effects of
Molybdenum in Drinking Water," EPA600/1-79-006, 1979.
Do72 Dollahite, J. W., et. al., "Copper Deficiency and
Molybdenosis Intoxication Associated with Grazing Near a
Uranium Mine," The Southwestern Veterinarian, Fall 1972.
EPA76 Environmental Protection Agency, "National Interim
Primary Drinking Water Regulations," EPA 570/9-76-003,
1976.
EPA77a Environmental Protection Agency, Proceedings: A
Workshop on Policy and Technical Issues Pertinent to the
Development of Environmental Protection Criteria for
Radioactive Wastes, ORP/CSD-77-1, 1977.
EPA77b Environmental Protection Agency, Proceedings: A
Workshop on Policy and Technical Issues Pertinent to the
Development of Environmental Protection Criteria for
Radioactive Wastes, ORP/CSD-77-2, 1977.
EPA78 Environmental Protection Agency, Proceedings of a Public
Forum on Environmental Protection Criteria for
Radioactive Wastes, ORP/CSD-78-2, 1978.
EPA82 Environmental Protection Agency, "FEIS for Remedial
Action Standards for Inactive Uranium Processing Sites
(40 CFR 192)," EPA 520/4-82-013-1, Oct 82.
ICRP78 International Commission on Radiological Protection,
"Limits for Intakes of Radionuclides by Workers," ICRP
Publication 30, Pergamon Press, 1979.
LuSOa ; Luo, X. M., et. al., "Molybdenum and Esophageal Cancer
in China," Southeast-Southwest Regional American
Chemical Society Annual Meeting Abstracts, 40, 1980.
7-23
-------
LuSOb Luo, X. M., et. al., "Preliminary Analysis of the
Distribution of the Esophageal Cancer Mortality Rates,"
Geographical Environment and Chemical Elements in Food
and Drinking Water in Anyang Administrative Region,
Honan Province, Chinese J. Oncol. 2:74-80, 1980.
NAS72 National Academy of Science, "Water Quality Criteria,
1972," EPA-R3-73-033, NAS, Washington, 1972.
NAS80 National Academy of Science, "Drinking Water and Health,
Volume 3," NAS, National Academy Press, Washington, 1980
NAS83 National Academy of Science, "Drinking Water and Health,
Volume 5," NAS, National Academy Press, -Washington, 1983
Ti88 Titus, Frank B., Jacobs Engineering Group, Inc., Oral
presentation at DOE/NRC Hydrology Work Group Meeting,
Albuquerque, NM, October 27, 1988.
Ve78 Venugopal, B. and T. D. Luckey, "Metal Toxicity in
Mammals, Volume 2: Chemical Toxicity of Metals and
Metoloids," Plenum Press, New York, 1978.
7-24
-------
-------
------- |