SUMMARY OF GROUND-WATER QUALITY IMPACTS
OF URANIUM MINING AND MILLING IN
THE GRANTS MINERAL BELT, NEW MEXICO
Robert F. Kaufmann
Gregory G. Eadie
Charles R. Russell
August 1975
U.S. Environmental Protection Agency
Office of Radiation Programs
Las Vegas Facility
Las Vegas, Nevada 89114
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TABLE OF CONTENTS
Page
TABLE OF CONTENTS " i
i
TABLES iii
FIGURES iv
PURPOSE OF STUDY 1
SUMMARY AND CONCLUSIONS 3
RECOMMENDATIONS 10
AREAL DESCRIPTION 12
Location and Description of
Study Area 12
Principal Industries 14
GEOLOGY AND HYDROLOGY 16
INDUSTRY-SPONSORED WATER QUALITY
MONITORING PROGRAMS 21
Introduction 21
Adequacy of Water Quality Data
and Monitoring Programs 22
GROUND-WATER QUALITY IMPACTS 26
Introduction 26
Bluewater-Milan-Grants ^5
United Nuclear-Homestake Partners
Mill and Surrounding Area 40
Ambrosia Lake Area 44
Churchrock Area 47
Jackpile-Paguate Area 49
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Significance of Radiological Data 51
Regulations and Guidelines 51
Radium-226 52
Other Radionuclides 55
REFERENCES CITED .. 57
11
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TABLES
Tables
1. Uranium Economy of New Mexico
2. Sampling Point Locations and Gross Chemical
Data for Ground-Water Samples from the
Grants Mineral Belt, New Mexico 27
3. Selenium and Vanadium Concentrations in
Selected Ground-Water Samples 30
4. Radiological Data for Selected Ground-Water
Samples 31
5. Typical Background Radionuclide Concentra-
tions by Geographic Area and Aquifer 34
6. Summary of Reported Concentrations for
Radium, Gross Beta, and Natural Uranium
in Ground Water in the Grants Mineral Belt 37
7. Locations with Radium-226 in Excess of the
PHS Drinking Water Standard 54
8. Radium Concentrations for Municipal Water
Supplies 54
9. Maximum Permissible Concentrations in Water 56
111
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FIGURES
Figures Page
1. Map of Northwestern New Mexico Showing
General Location of Sampling Areas in
the Grants Mineral..Belt 13
2. Generalized Structure Section from
Bluewater to Ambrosia Lake 17
3. Generalized Structure Section from
Gallup to Churchrock Mining Area 18
4. The Anaconda Company Uranium Mill and
Tailings Pond-Bluewater 36
5. Radium and Nitrate Concentrations in
Ground Water in the Grants-Bluewater Area 38
6. Radium, TDS and Chloride in Ground Water
Near the United Nuclear-Homestake Partners
Mill 42
7. Water Table Contours and Well Locations at
the United Nuclear-Homestake Partners Mill
Site 43
8. Radium Concentrations in Ground Water in
the Ambrosia Lake Area 46
9. Radium Concentrations in Ground Water in
the Churchrock-Gallup Area 48
10. Radium Concentrations in Ground Water in
the Paguate-Jackpile Area 50
IV
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PURPOSE, OF STUDY
In September 1974, the State of New Mexico Environ-
mental Improvement Agency (NMEIA) made a request of Region
VI of the U.S. Environmental Protection Agency (USEPA) to
conduct a definitive survey of the Grants Mineral Belt area
(Wright, 1974). At this time, a summary report evaluating
the problem areas in the study area was also prepared by
Region VI (Keefer, 1974). -Briefly, the water-quality impacts
associated with ongoing and projected uranium mining and
milling were unknown. Whether a problem existed \\ras ques-
tionable but \\rorthy of investigation because of the toxic
nature of the effluents and their persistence in the environ-
ment. The study areas of most concern were located near
Churchrock, Ambrosia Lake-Grants and Laguna-Paguate.
In late November 1974, the Office of Radiation Programs-
Las Vegas Facility (ORP-LVF) and the National Enforcement
Investigations Center (NEIC)-were requested by Region VI to
provide direct assistance to the NMEIA to conduct the study.
Representatives of ORP-LVF, NEIC, and NMEIA completed
a field reconnaissance of the study area during the week of
January 24, 1975. Industry representatives were contacted,
arrangements were made for site access, and sampling locations
and collection schedules were finalized after revaewing com-
pany monitoring programs. Study plans were prepared by both
ORP-LVF and NEIC defining study participants, responsibilities,
and specific analyses to be completed per location by each
laboratory.
Subsequent meetings between the three participating
agencies resulted in a final study plan which defined the
following study objectives to the satisfaction of NMEIA
(Bond, 1975):
1. Assess the impacts of waste discharges from uranium
mining and milling on surface waters and ground waters of the
Grants Mineral Belt.
2. Determine if discharges comply with all applicable
regulations, standards, permits, and licenses.
3. Evaluate the adequacy of company water quality moni-
toring networks, self-monitoring data, analytical procedures,
and reporting requirements.
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4. Determine the composition of potable waters at ura-
nium mines and mills.
5; Develop priorities for subsequent monitoring and
other follow-up studies.
Ground-water aspects of objectives 1, 3, and 5 were the
responsibility of ORP-LVF whereas the remaining objectives
were pursued by NEIC.
Actual sample collection began in late February, 1975,
in the Ambrosia Lake-Blue\\rater area. It proceeded to Paguate-
Jackpile and was finally completed in the Gallup-Churchrock-
area in early March, 1975. Laboratory analyses for the trace
metals, gross alpha, and radium-226 analysis were completed by
NEIC and the other radiological analyses were completed by the
Environmental Monitoring and Support Laboratory. Radiometric
analyses w^re assigned at the highest priority at each labora-
tory and were completed, in July 1975.
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SUMMARY AND CONCLUSIONS
TASK: Assess the Impacts of Waste Discharges from Uranium
Mining and Milling on Surface and Ground Waters of
the Grants Mineral Belt
1. Ground water is the principal source of water
supply in the study area. Extensive development from the
San Andres Limestone aquifer occurs in the Grants-Bluewater
area where the water is used for agriculture, public water
supply, and uranium mill feed water. Development of shallow,
unconfined aquifers developed in the alluvium also occurs
in this area. Principal eround-water development in the
mining areas at .Ambrosia Lake, Jackpile-Paguate, and Church-
rock is from the Morrison Formation and, to a lesser extent,
from the Dakota Sandstone or the Tres Hermanos Member of
the Mancos Shale. The Gallup water supply is derived
primarily from deep wells completed in the Gal]up Sandstone.
The well fields are located in the urban area and, more
recently, 11 kilometers north of the city.
2. Contamination of shallow ground water, largely
used for livestock watering, results from the infiltration
of 1) effluents from mill tailings ponds, 2) mine drainage
water that is introduced to settling lagoons and natural
water courses, and 3) discharge (tailings) from ion exchange
plants. It is unlikely that seepage from these sources
returns to the deep bedrock aquifers. Deterioration of
water quality in the latter occurs in the mining areas as
a result of penetration or disruption of the ore body coin-
cident with underground mining. The most dramatic changes
are greatly increased dissolved radium and uranium. Induced
movement of naturally saline ground ivater into potable
aquifers is also likely but undocumented.
3. With the exception of the area south and southwest
from the United Nuclear-Homestake Partners mill, widespread
ground-water contamination from mining and milling was not
observed in the study area. In the vicinity of the Anaconda
mill, radium and nitrate concentrations in the alluvial aqui-
fer decline with distance from the tailings ponds, but no-
where does either parameter exceed the drinking water limit.
Contamination of ground water with radium was not observed
despite concentrations of as much as 178 pCi/1 in mine and
mill effluents. padium removal is pronounced, primarily.
due to sorptive capacity of soils in the area.
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4. Mining practices, per se, have an adverse effect
on natural i^ater quality. Initial penetration and disruption
of the ore body in the Churchrock mining area increased the
concentration of dissolved radium in ground water pumped
from the mines from 0.05 to 0.62 pCi/1 to over 8 pCi/1.
Subsequent development work over a two-year period increased
the concentration to over 20 pCi/1, or 23 times the natural
concentration. If the pattern in Ambrosia Lake is- repeated,
ultimate concentrations of 50 to 150 pCi/1 are expected.
5. Ground water in parts of the shallow aquifer down-
gradient from the United Nuclear-Homestake Partners mill
is contaminated with selenium, and alternative supplies
should be developed. The he^t alternative is deeper wells
completed in the rhinle formation or, preferably, the under-
lying San Andres Limestone.
6. Seepage from the Anaconda tailings pond at Blue-
water is estimated to average 183 million liters/year (48.3
million gallons) for 1973 and 1974. The average volume in-
jected for the same time period was 348 million liters/year
(91.9 million gallons). Therefore, approximately one-third
of the waste enters the shallow aquifer, which is a source of
potable and irrigation water in Bluewater Valley. From 1960
through 1974, seepage is estimated to have introduced. 0.41
curies of radium to the shallow potable aquifer. .Adequate
monitoring of the movement of these wastes is not underway.
7. There are indications that waste injected into the
Yeso Formation by the Anaconda Company are not confined to
that unit as originally intended in 1960. Three nearby moni-
toring wells, completed in the shallower San Andres Lime-
stone and/or the Glorieta Sandstone show a trend of increas-
ing chloride and uranium with time. Positive correlations of
water quality fluctuations with the volumes of waste injected
are a further indication of upward movement. The absence of
monitoring wells in the injection zone is a major deficiency
in the data collection program.
8. The maximum concentration of radium observed in
shallow ground water adjacent to the Kerr-McHee mill at
Ambrosia Lake was 6.6 pCi/1. Calculated seepage ^rom the tail-
ings ponds occurs at the rate of 491 million liters/year (130
million gallons/year), and has contributed an estimated 0.7
curies of radium to the ground water to date. This is 29 per-
cent of the influent to the "evaporation ponds" and attests to
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their poor performance in this regard. Padium and gross alpha
in the seepage are 56 pfi/l and 112,000-144,000 pCi/1, respec-
tively. Wells completed in bedrock and in alluvium along water
courses containing mine drainage and seepage from tailings ponds
contain elevated levels of TDS, ammonia, and nitrate. One well,
now contaminated with 3.7 pCi/1 of radium, contained 1.0 pCi/1
in 1962. Sorption or bio-uptake of radium is nronounced, hence
concentrations now in ground water are not representative of .
ultimate concentrations.
9. Contamination of the Gallup municipal water supply
by surface flows consisting mostly of mine drainage is ex-
tremely unlikely because of geologic conditions in the well
field. Another well field north of the City will, in no
way, be affected by the drainage.
10. Water quality data from 11 wells over a 200-square
kilometer area in ,.the Puerco Piver and South 'Pork Puerco
Piver drainage basins revea] essentially no noticeable
increase in concentrations of radionuclides as well as gross
and trace constituents in ground water as a result of mine
drainage. Natural variations in the uranium content of
sediments probably account for differences in radium content
in shallow wells. Dissolved radium in shallow ground water
underlying stream courses affected by waste water is essen-
tially unchanged from areas unaffected by mine drainage.
None of the samples contained more than recommended maximum
concentrations for radium-226, natural uranium, thorium-2.30,
thorium-232, or polonium-210 in drinking water. However,
the paucity of sampling points and the absence of historical
data make the ^oregoing conclusion a conditional one, par-
ticularly in the reaches of the Puerco River within approxi-
mately 10 kilometers of the mines.
11. Four i^ells sampled in the vicinity of the Jackpile
mine near Paguate contained 0.31 to 3.7 pCi/1 radium-226.
With the exception of the latter value from the new shop
well in the mine area, remaining supplies contain 1.7 pCi/1
or less radium. The Paguate municipal supply contains 0.18
pCi/1. None of the wells were above MFC for the other common
isotopes of uranium, thorium, and polonium. Hround water from
the Jackpile Sandstone may contain elevated levels of radium
as a result of mining activities. Mine drainage water ponded
within the pit contained 190 pCi/1 radium and 170 pCi/1 of
uranium in 1970. The impacts of mining on ground-water
quality downgradient from the mining area are unknown due to
the lack of properly located monitoring wells. No adverse .
impacts from mining on the present water supply source for
Paguate is expected.
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(o
12. Of the 71 ground-water samples collected for the
study, only two potable water supplies have radium-226 in
excess of the 3 pfi/1 PUS drinking water standard. These
are located downgradient from the Kerr-McHee mill and in
the Jackpile mining area.
13. The highest isotopic uranium and thorium, and
polonium-210 contents for any potahle water supply in the
study area are less than 1.72 percent of the total radionuc-
lide population guide-MFC as established in NMEIA regulations.
14. The lowest reported concentrations (background
levels) are summarized as follows:
Padionuclide Pange (pCi/1) Average (pCi/1)
radium-226 0.06 - 0.31 0.16
polonium-210 . 0.27 - 0.57 0.36
thorium-230 0.013 - 0.05] 0.028
thorium-232 0.010 - 0.024 0.015
U-natural 14 - 68 35
15. The uranium isotopes (uranium-234, -235, and -238)
are the main contributions to the gross alpha result; however,
in several determinations, the gross alpha result underesti-
mated the activity present from natural uranium.
16. No correlation was found relating a gross alpha
content greater than 5 pCi/1 to a radium-226 content in excess
of the 3 pCi/1 PHS drinking water standard.
17. It is doubtful that the gross alpha determination can
even be used as an indicator of the presence of other alpha
emitters (e.g., H-natural and polonium-210); and since the
gross alpha results have such large error terms, no meaningful
determinations of percentage of other radionuclides to gross
alpha result can be implied.
18. Gross alpha determinations also fail to indicate the
possible presence of lead-210 (a beta emitter) which, because
of the low MFC of 33 pri/1, may be a significant contributor
to the radiological health hazard evaluation of any potable
water supply.
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7
19. Radium-226 in ground water is a good radiochemical
indicator of waste water from mines and mills. It also pro-.
vides the best means of health evaluations due to the low
maximum permissible concentration.
20. Polonium-210 , thorium-230 and thorium-232 con-
centrations in ground water fluctuate about background levels
and are poor indicators of ground-water contamination from
uranium mining and milling activities.
21. For routine radiological monitoring of potable water
supplies, isotopic uranium and thorium, and polonium-210
analyses do not appear to be necessary due to their high
maximum permissible concentrations. (Chemical toxicity of
uranium may be a significant limiting factor, however.)
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Task: Evaluate tlie Adequacy of Company Water Quality Moni:
toring Networks, Self-Monitoring Data, Analytical
Procedures, and Reporting Requirements
1. Environmentally-oriented company sponsored ground-
water monitoring programs range from imperfect to nonexistent.
Actual monitoring networks are deficient in that sampling
points are usually poorly located or of inadequate depth/loca-
tion relative to the hydrogeologic system and the introduction
of contaminants thereto. Compared to the multi-million dollar
uranium industry, producing multi-billion liters of toxic
effluents, the ground-water sampling and monitoring programs
represent minimal efforts in terms of network design, imple-
mentation, and level of investment.
2. Company radiochemical analytical methods evident
to date are inadequate for measuring environmental levels
of radionuclides. , Of specific concern are overly high
minimum detectable activities and large error terms. Incom-
plete analysis of radionuclide contents prevails. Few data
are reported on other naturally occuring radionuclides such
as isotopic thorium, polonium-210, and radium-228.
In some cases, monitoring has been restricted to analysis
of radium-226 and natural uranium, without consideration of
these other radionuclides or toxic metals.
3. Monitoring of hydraulic and water-quality impacts
associated with conventional mining and with solution (in
situ) mining is not reported to regulatory agencies. It is
likely that such monitoring is limited to meeting short-
term economic, and engineering needs of the companies rather
than addressing long-term, general environmental concerns.
As a result, overall impacts on ground water are not rou-
tinely determined and reported.
4. Off-site ground-water sampling networks do not
utilize wells specifically located and constructed for
monitoring purposes. Reliance on wells already in existence
and utilized for domestic or livestock use falls short of the
overall monitoring objectives (i.e., to determine impacts
on ground water and to adjust company operations to accept-
able levels). Deficiencies of this type can allow contami-
nation to proceed unnoticed.
5. Proven geophysical and geohydrologic techniques
to formulate environmental monitoring networks, specify
sampling frequencies, a;nd provide data to adjust subsequent.
efforts are, with few exceptions, not part of the industrial
efforts with respect to ground water.
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6. Monitoring the effects of the Jackpile and Paguate
open pit mines on ground-water quality is non-existent,
despite the magnitude of these operations. Whereas back-
ground radium concentrations are less than 4 pCi/1, drainage
water within the pits contains 190 pCi/1. Padium in two wells
used for potable supply and completed in the ore body is also
elevated above background, further indicating a need for data
to determine what the future impacts might be when mining
ceases and before additional programs for heap leaching
and in situ mining are implemented.
7. Careful analysis of material and water balances
for the various tailings disposal operations is not evident.
For the Anaconda Company, the method utilized has not been
altered in 14 years and for Kerr-McGee, overland flow
into the ponds is erroneously regarded as negative seepage
or as an influx of ground water.
8. Records of U.S. Atomic Energy Commission (USAEC)
inspection reports, mill license applications, seepage reports,
etc., on file with the State appear to be incomplete and not
readily accessible. No interpretive summary or review-type
reports utilizing the monitoring data reported by industry
are available from either the State or the USNRC. Liberal
mill licensing conditions with respect to ground-water mon-
itoring and water quality impacts were initially established
by the U.S. Atomic Energy Commission (USAEC) and have been
followed by scant review or no review, in any critical sense,
of company operations. The uranium mining and milling indus-
try has not been pressed to monitor and protect ground-water
resources. Prior to the present study requested by the State
of New Mexico, the efforts put forth by industry to date have
largely not been reviewed by regulatory agencies at the State
and Federal levels.
TASK: Develop Priorities for Subsequent Monitoring and
Other Follow-Up Studies
(See RECOMMENDATIONS)
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RECOMMENDATIONS
1. Improved industry-sponsored monitoring programs
should be implemented and the data made publicly available
to detect likely hydraulic and water quality impacts from
uranium milling and mining (open pit, underground, in situ).
Revamped programs, specifically developed by joint- concur-
rence of industry and regulatory agencies, should be incor-
porated in licenses, where possible. Licenses should spe-
cify minimal radiochemical analytical methods for detecting
specific radionuclides as well as requirements for partici-
pation in quality assurance programs. Specific reporting
procedures should include raw data, summary reports, and
interpretations of data. Conclusions concerning impacts of
operations on ground-water quality and remedial steps taken
to abate or eliminate adverse impacts should be prepared.
2. Additional legislation at Federal and State levels
should be developed to supplement existing authority under
the National Polution Discharge Elimination System (NPDES) ,
the Safe Drinking Water Act, and State water quality regu-
lations to effect stricter controls on environmental mon-
itoring and reporting with respect to ground water.
3. With regard to the Anaconda \vaste injection program,
all available chemical and water level data for pre-injection
and post-injection periods should be evaluated to ascertain
if waste is migrating out of the Yeso Formation and into
overlying aquifers containing potable water. Of particular
concern are radium-226 and thorium-230 because of its abun-
dance (82,000 pCi/1) in the injected fluid.
4. Available chemical data for ground-water samples
collected by Kerr-McGee from wells located adjacent to
Arroyo del Puerto and San Mateo Creek should be evaluated
for long-term trends in water quality. Data for the Wil-
coxson (P. Harris), Bingham, Marquez, and County Line Stock
Tank wells are of principal concern.
5. Water-quality data from the newly completed moni-
toring wells peripheral to the Kerr-McGee mill should be
cross-checked using outside laboratories to determine the
extent of contamination in the Dakota Sandstone.
6. If the verified source of ground-water contamina-
tion in the Broadview Acres .and Murray Acres subdivisions
is the nearby uranium mill,'a sound monitoring program
should be developed to predict off-site contaminant migra-
tion and to determine if there is a need for remedial action.
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7. The breadth of mining and milling activities in
the Grants Mineral Belt clearly requires additional study
if ground-water impacts are to be understood in any detailed
or quantitative sense. The present study provides a pre-
liminary assessment of but a small facet of the overall
activity in the district. Further study is recommended to
determine impacts of past operations or expected impacts
from mines and mills now in the planning or construction
stage. Site specific investigations are necessary to deter-
mine the hydraulic and water quality responses to dewatering
and solution mining.
8. Additional ground-water samples should be collected
from wells adjacent to the Rio Puerco and east of Gallup to
determine if radium concentrations are acceptably low and
to establish baseline conditions for future reference. Con-
centrations of trace metals should also be measured (recom-
mended) for the latter reason.
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12
AREAL'DESCRIPTION
of Study Area
The Grants Mineral Belt, located in the south-
eastern part of McKinley County and the north-central
portion of Valencia County, is a rectangular shaped
area in northwestern New Mexico (John' and West, 1963).
It is 24 to 32 kilometers-wide in the north-south direction
and 137 to 177 kilometers.long from east to west (see Figure
(Kelley, 1963; Kittel, Kelley, and Melancon, 1967).
At present, three mining districts dominate the
Mineral Belt. These are Churchrock on the west, Grants -
Ambrosia Lake in the center', and Paguate-Jackpile on
the east. These contain the Gallup, Churchrock, Smith
Lake, Ambrosia .Lake, Grants, North Laguna, and South
Laguna mining areas. The districts are physiograph-
ically separated by Mt. Taylor, which separates Laguna
lying to the east and Grants and Gallup to the west
(Kelley, 1963; Kittel, Kelley, and Melancon, 1967).
The Continental Divide, extending through approxi-
mately the middle of the area, separates the region
into two areas of drainage. West of the Divide streams
and rivers drain into the Gulf of California via the
Colorado River system, while to the east they eventually
join the Rio Grande (Button, 1885). Nearly all the
streams in the area are intermittent and flow only dur-
ing periods of intense precipitation (Cooper and John,
1968; Gordon, 1961).
The Grants Mineral Belt of northwestern New Mexico
is within the Navajp and Datil sections of the Colorado
Plateau physiographic province (Fenneman, 1931). To
the east are the Southern Rocky Mountains and to the
west and south, the Basin and Range province. To the
north lie the Central Rocky Mountains.
Characteristic landforms within the study area
include rugged mountains, broad, flat valleys, mesas,
cuestas, rock terraces, steep escarpments, canyons,
lava flows, volcanic cones, buttes, and arroyos
(Kittel, Kelley, and Melancon, 1967; Cooper and John,
1968). Lava flows and volcanic necks are the predomi-
nant landmarks of the Datil section (Fenneman, 1931).
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13
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14
There are no perennial, streams in southeastern
McKinley County. These and' the natural depressions
such as'Ambrosia Lake, Casamero Lake and Smith Lake
contain water only after heavy rains.' There are inter-
mittent ponds and lakes in" the volcanic craters of the
Cebollcta Mountains. The--only perennial source of
water is part of Bluewater Lake at the junction of Azul
and Bluewater Creeks (Cooper and John, 1968).
1 I n d u s t r i e s
The principal industries in McKinley and Valencia
Counties of northwestern New Mexico, until relatively
recently, were farming and ranching. Tourism and small-
scale logging were secondary. The land is mostly used for
livestock grazing, while some irrigated farming is clone in
the valleys of Bluewater Creek and the Rio San Jose. The
main crops are vegetables, and plants exist in the area for
processing and packaging them.
Now that: uranium ore has been found to be wide-
spread throughout the Grants Mineral Belt, the uranium
mining and milling industry predominates. What was a rural
agricultural economy has metamorphosed into an industrial
one> The figures on Table 1 indicate the importance of
the uranium industry in the economy of New Mexico, especially
the northwest part. The growth of the uranium industry has
created a need for associated industries and services,
especially the chemical industry. Caustic soda and soda ash
are the main alkalies used in uranium milling. The construc-
tion and housing industries have flourished, and mining
supply firms and concrete companies have been established
(Gordon, 1961).
Gallup and Grants have grown rapidly, as have some of
the smaller villages and communities. The population of
McKinley County has grown from 27,451 in 1950 to 43,208 in'
1970, and. that of Valencia from 22,481 to 40,539 (Univer-
sity of -New Mexico, Bureau of Business Research, 1972).
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' GEOLOGY AND HYDROLOGY
The principal bedrock and alluvial stratigraphic
units in the Grants Mineral Belt range in age from
Pennsylvania!! to Recent (Hilpert, 1963). Figure 2 through
the Grants and Ambrosia Lake areas portrays these units and
the dominant structural feature which is the Chaco slope
developed on the north flank of the Zuni uplift. Conditions
in the Churchrock area are essentially the same.
Pronounced topographic expression of the gently
sloping bedrock units is abundantly evident in the
Grants Mineral Belt. The sandstone strata on the
mesas, actually gently dipping cuestas, form protective
caps which resist weathering, The concave slopes
and bottom lands form on Jess resistant units, typi-
cally shales and thin-bedded sandstones interbedded
with shale. Although geographically less extensive,
.lava beds and limestone strata also function as caprocks.
Due to the scarcity of perennial surface water bodies,
ground water is the principal source of water in the study
area. Industrial, municipal, stock, and private domestic
wells tap both bedrock and alluvial aquifers. In general,
wells of low to moderate productivity, are possible in the
unconsolidated valley fill which con-stitutes an aquifer,
primarily along the broad valleys of the Rio San Jose and
the Rio Puerco. Numerous shallow domestic wells south
and southwest of the United Nuclear-Homestake Partners mill
also tap shallow, unconfined aquifers. Part of the water
supply for Gallup, and essentially all of that for Milan
and Grants, is derived from shallow wells tapping valley
fill and interbedded basalt layers (Dinwiddie et. al., 1966)
-------
17
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19
Process water for the various uranium mills is derived
from deep wells tapping bedrock aquifers. This is true for
the Anaconda Company and United Nuclear-Homestake Partners'
mills, both of which tap the San Andres Limestone. Part of
the feed 'water for the Kerr-McGee mill is from wells in the-
Morrison Formation and the more deeply buried Glorieta Sand-
stone and San Andres Limestone, with the balance coming from
treated mine drainage water. Without exception, the opera-
ting mines continuously pump ground water as part of the
mining operation. Where economical concentrations of uranium
are present, ion exchange plants are operated to effect
recovery from the waste streams, but radium removal is not
practiced. In effect, the various mines are high capacity .
wells which locally dewater.the ore-bearing formations,
chiefly the Westwater Canyon Member of the Morrison Forma-
tion and to a lesser extent, the overlying strata such as
the Dakota Formation.
The impacts of ground-water pumping and discharge to
surface water courses are xraried. Declining water levels in
the aquifers tapped, and possibly in the adjacent formations,
are immediately noticeable. For example, in the Churchrock
area, the static water level in the old Churchrock mine is
declining about 0.3 m/mo clue to dewatering at the United
Nuclear and Kerr-McGee mines. Discharge of the mine water
transforms nearby dry washes and ephemeral streams into
perennial ones. Rio Puerco, Arroyo del Puerto and San
Mateo Creek are cases in point. Water introduced to these
channels will persist until the losses due to bed infiltra-
tion, evapotranspiration, and diversion equal inflow. In-
filtration of such waters to shallow alluvial aquifers may be
adverse, depending on the quality of infiltrating water
relative to ambient water quality in the aquifer and the use
to which shallow ground water is or will be put. The com-
bination of declining water levels in the deeper, bedrock
aquifers and deteriorated water quality in the shallow
aquifers may have particularly adverse impacts on stock wells
also used by the local populace for potable supply.
Sorption of radionuclides such as radium on the stream
sediments may result in a buildup of material that will later
be dispersed by channel scouring associated with flash flood-
ing. Both the gradual buildup of radium in the sediments
and its subsequent redistribution will result in increased
levels of radioactivity in the environment as compared to
ambient, pre-mining conditions.
-------
20
Uranium mining and milling in the study area are of
particular importance to several aquifers in the study area.
Wastes from the Anaconda Company mill in Bluewater have
infiltrated via the tailings pile and affected the shallow,
unconfined aquifer (Tsivoglou and O'Connell, 1962). Injec-
tion of wastes into the deeply buried-Abo and Yeso Formations
has increased radioactivity and salinity levels therein.
Strictly speaking, these-are not considered aquifers because
of the mineralized water naturally present, and the impacts
were expected or predicted beforehand. However, should the
contamination move upward into potable aquifers and extend
too far laterally, injection would likely be terminated.
Widespread contamination of the shallow aquifer adjacent to
the tailings pond would similarly require abatement.
The Chinle Formation is a source of domestic water in
the Murray Acres and Broadview Acres subdivisions down-
gradient from the United Nuclear-Homestake Partners mill.
As will be shown below, the shallow alluvial aquifer in this
area is already believed to be contaminated by the infil-
tration of effluents from the mill.
In the Ambrosia Lake area, contamination of shallow
ground water is likely to be a result of infiltration of
1) effluents from the tailings ponds at the Kerr-McGee
mill, 2) mine drainage water that is introduced to settling
lagoons and natural water courses, and 3) discharges from
ion exchange plants. Seepage from the now inactive United
Nuclear, Inc., (formerly Phillips) mill tailings pile is also
undoubtedly present in the shallow subsurface ,
The ultimate impact of these waste waters on
ground water quality is unknown. It is unlikely that seepage
returns to the deep, bedrock aquifers will occur because of
their relatively great depth and the presence of numerous
impermeable layers between the shallow alluvial materials
and the principal aquifer (V/estwater Canyon Member). Very
limited volumes of water in the shallow alluvium render
it an insignificant source of supply. What water is
present near the mining and milling areas is now likely to
be contaminated to varying degrees by industrial effluents.
The long-term infiltration of radium-laden water along the
stream'channel of San Mateo Creek may adversely affect the
quality of shallow ground water now developed for stock
watering, both above and below the confluence with Arroyo
del Puerto.
-------
21
The potential for future problems of water availability
for ore processing in Ambrosia Lake have been cited by
Cooper and John (1968). In essence, dewatering of the prin-
cipal aquifer (Westwater Canyon Member of the Morrison
Formation) to facilitate mining may necessitate use of the
poorer quality water in the underlying Bluff Sandstone.
Hydrogeologic conditions in the vicinity of the Church-
rock mines basically resemble those in Ambrosia Lake with
respect to potential impacts of mining and milling on ground
water. The potential for contamination of shallow ground-
water resources is greatest along the channel of the Rio
Puerco. Under natural conditions, shallow ground water was
scarce or nonexistent; hence, deeper wells completed in
bedrock are required for a reliable supply. With continued
infiltration of mine drainage water, at least local satura-
tion of the alluvium may occur and lead to ground water
development using shallow wells. However, the radium con-
tent of the drainage water discharged to date is excessive
for potable or stock use of such water, and long term
recharge with mine drainage water is not recommended. The
potential for contamination of shallow wells along the Rio
Puerco, particularly on the east and west fringes of Gallup,
is unlikely*
1NDUSTRY^SPONSOI^ MONITORING PROGRAMS
I n t rodu c 11on
A principal goal of the project was to evaluate the
nature and extent of water monitoring programs, and data
therefrom, as implemented by industry. This presumed that
descriptions of the sampling points, analytical procedures,
and resulting data would be available' for examination upon
request to the companies. With the exception of the Ana-
conda Company, this was not the case.
The inadequacies of industry-supported testing and
monitoring programs noted by Clark (1974) include lack of
sufficient data, intermittent data, and unreliable data....
conclusions, which are at least not contradicted by the
present study.
The most extensive monitoring and testing programs
to detect ground-water contamination are conducted by Kerr-
McGee and Anaconda. By comparison, United Nuclear and
United Nuclear-Homestake Partners have minimal programs
both at the mines and at the mills. Therefore, the Kerr-McGee
and Anaconda programs, although in need of revision, are a
marked improvement compared to inactivity.
-------
22
Of greatest environmental concern is the discharge of
waste water originating from mining and from ore processing
Included in the latter is the discharge stream or tailings
from conventional acid and alkaline leach mills and from
ion-exchange plants. A third problem area, concerning im-
pacts on ground-water quality from solution mining in the
Ambrosia Lake area, is essentially unknown outside the
industries involved.
Identification of industrial ground-water monitoring
programs, if any, to determine hydraulic and water quality
responses to both shaft and solution mining were beyond the
scope of the present project. It is expected that solution
mining and the use of IX plants, with and without recycling,
will gain in popularity, particularly if stricter discharge
limits for uranium induce greater capital investment in IX
equipment. For this reason, and also because of the heavy
ground-water extraction associated with deep mining,
deliberate monitoring programs should be implemented and the
data made publicly available to detect likely hydraulic and
water quality responses .
Adequacy of Water Quality' Data and Monitoring Programs
Evaluating the adequacy of a ground-water monitoring
program is rather subjective and rarely will there be
unanimity of opinion. The diversity of mining activities
and geologic or hydrologic settings necessitates great
variety in program design. Outlooks and goals of diverse
groups also play a large-role.
On the basis of the information utilized, the principal
deficiencies with ongoing programs can be classified under
the following headings:
1. Ground-water monitoring
2. Analytical techniques and reporting procedures
3. Regulatory agency review
-------
23
Existing ground-water sampling networks range from
non-existent to defective. The non-existent networks in-
volve entire operations, as in the case of the United Nuclear
Corporation^or portions of operations, as in the case of the
solution mining conducted by United Nuclear-IIomestake Partners
The latter's monitoring of a single wel] to determine shallow
ground-water contamination is considered grossly deficient.
In essentially every instance of mining and milling, baseline
ground-water conditions were not defined, hence any changes
due to disruption of natural conditons cannot be assessed.
In the case of the Anaconda waste injection program, for
example, there is no information concerning pre-injection
concentrations of stable and radioactive chemical species
in overlying potable reservoirs possibly already affected
by the wastewater.
Of the active ground-water monitoring programs that
were reviewed, great reliance is placed on documenting
the quality of water in active wells within the surround-
ing region. This is laudable with respect to current water
use, but-not especially productive in terms of defining
water quality impacts. In many instances, sampling wells
are located hydraulically upgradient or are so far removed
from the likely effects of mining or milling as to show no
change. Wells of excessive depth, i.e., below the aquifer
likely to show change, are also of dubious value as monitor-
ing points. With the exception of a portion of the Kerr-
McGee onsite net, wells specifically constructed for monitor-
ing are commonly too few in number and improperly situated
with respect to depth and (or) location. Compared to the
multi-million dollar uranium industry, producing multi-
billion liters of toxic effluents, the ground-water sampling
and monitoring programs represent minimal efforts in terms
of network design, implementation, and level of investment.
There are indications that deterioration in water quality-
is occurring through time and very possibly in response to
the waste volumes disposed of in the last 15 years. With
regard to this disposal scheme, there is real question as
to whether the data that have been generated have been scru-
tinized. In other instances, expected adverse impacts of
seepage on shallow ground water have not been found because
they have either not been sought or have been sought in
unlikely locations.
-------
24
No response to the requests for information regarding
analytical methods and reported results was received from
three of the four companies contacted. A review of the
available records by the authors at the New Mexico Environ-
mental Improvement Agency indicates many deficiencies in
the company programs. These deficiencies include lack of
information concerning minimum detectable activities for
analytical procedures utilized, overly large error terms,
poor agreement with outside laboratories, absence of quality
assurance programs, inability to detect radionuclides at truly
environmental or background levels, and irregular or random
sampling frequencies. Analysis for specific radionuclides
such as thorium, lead-210, polonium-210, radium-228, all of
which are associated with mining and milling effluents, is
rarely done. With the exception of the Anaconda Company,
results of monitoring programs to determine background levels
of both radionuclides or chemical components are not discussed
in any of the reports of the companies. From the data/reports
reviewed, it is unknown whether the various company labora-
tories have the analytical capabilities to accurately analyze
for environmental levels of the common radionuclides associated
with the uranium mining and milling industry.
During February 11 and 12, 1975, a brief review of
available company records, USAEC inspection reports, and
mill licenses in the possession of NMEIA was conducted.
The following findings are preliminary, as not all of the
company records were available at the time of the review:
1. The available records are disorganized and incomplete.
A complete copy of each company's radioactive material li-
cense and supporting correspondence could not be found. Radio-
logical monitoring data reports were often missing or incom-
plete. Attachments and maps referred to in correspondence
in the records could not be found.
2. Except for the license condition requiring monitor-
ing data related to the Anaconda waste iniection program, USAEC
licenses for the other uranium mills have never specifi-
cally required the establishment of ground-water monitoring
networks or reporting of any data pertaining to such moni-
toring. (Some limited programs have, however, been described
in company license applications).
-------
25
3. It appears that no effort has been made to review
or to summarize the reported monitoring data. No interpretive
or summary reports concerning environmental impact have been
prepared.
4. Almost no information lias been reported by the com-
panies describing their radiochemical analytical procedures,
quality assurance programs, or the accuracy and precision
of reported results.
5. Reports of company efforts to evaluate the fate of
liquid tailings waste effluents (e.g., materials and water
balances between input versus evaporation, spillage, or
ground seepage and total pound capacity) are essentially
non-existent.
Noted deficiencies at the Federal level stem largely
from the rather liberal, initial licensing conditions (with
respect to ground-water monitoring), perfunctory inspection
of company monitoring programs and data, and, in general,
the somewhat haphazard manner in which information was filed
and catalogued for later reference. Simply put, the uranium
mining and milling industry has not been overly pressed to
monitor and protect ground-water resources and what efforts
they have put forth have largely not been reviewed.
-------
26
GROUND-WATER QUALITY IMPACTS
Introduction
The breadth of mining and milling operations in the
study area clearly requires additional study if ground-water
impacts are to be understood in any detailed or quantitative
sense. The following discussion must necessarily be regarded
as a preliminary assessment of but a small facet of the over-
all mining and milling activity. Impacts of inactive opera-
tions, such as the Phillips mill, or future impacts from
sources under development, such as the Gulf mine and mill
in San Mateo or the nearby Johnny M mine, are not addressed
herein. Very large voids in our knowledge of impacts on
water sources include solution mining practices and dewater-
ing of ore bodies. Essentially no data or interpretive
reports are available outside industry circles that describe
the hydraulic and water quality impacts of these operations,
which may well have the greatest impact of all on ground-
water.
Contaminated and background concentrations of selected
radionuclides, as well as'gross and trace chemical constituents,
were determined for 71 wells in the study area. These data
are presented in Tables 2 through 5. In certain locations,
these data relate to surface water phenomena such as natural
streams or to manmade features, foremost of which are tail-
ings disposal ponds or streams originating as mine discharge.
The data are discussed by study area and by uranium
mining/milling activities therein.
Table 5 summarizes background data from the present
study and categorizes the data according to study area
and aquifer. These reported values are the lowest concen-
trations reported for samples collected during the study
and may not necessarily represent "true" background or
ambient values that may have existed prior to uranium
mining and milling activites in this area. For the most
part, the values shown for "bedrock" aquifers are not from
the principal ore-producing formations, namely the West-
water Canyon Member of the Morrison Formation. In the
Grants-Bluewater area, "bedrock" refers primarily to the
San Andres Limestone, whereas near the United Nuclear-
Homestake Partners mill, the term includes the San Andres
Limestone and the Chinle Formation. At Ambrosia Lake,
the Westwater Canyon Member and the Bluff Wingate Sandstones
were sampled, whereas bedrock aquifers in the Churchrock
area mostly include the Dakota Sandstone.
-------
27
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Table 3
Selenium and Vanadium Concentrations
in Selected Ground-water Samples
NUMBER
United
9102
9107
9113
9134
9135
Grants
9117
9118
9119
9120
9121
9123
9129
DESCRIPTION Se (mg/1)
Nuclear-Homestake Partners
G. Wilcox
C. Worthen
C . Meador
Well #2 (UNHP) -
Well D (UHNP)
Bluewater
Monitor well (Anaconda)
Well #2
Well #4
Mexican Camp
Berryhill, Section 5
Engineer's well
Jack Freas
1.06
1.06
' 0.20
<0.01
1.52
0.01
0.01
<0.01
<0.01
<0.01
0.01
0.02
V (mg/1)
<0.3
0.3
0.3
1.3
0.4
0.3
0.8
0.9
1.0
0.8
1.1
1.3
Ambrosia Lake
9132
9201
9207
9208
9209
9211
9213
9214
9215
9219
N. Marque z windmill
KM-46, P. Harris (Wilcoxson)
KM--S-12
KM- 4 3
KM- 4 4
KM- 4 8
KM-B-2
KM- 3 6- 2
KM- 4 6
KM- 5- 2
.13
<0.01
<0.01
.29
.01
<0.1
<0.1
.02
<0.01
0.01
< .3
< .3
0.4
0.8
<0.3
0.5
O.G
<0.3
<0.3
<0.3
Gallup-Churchrock
9138
9140
9141
9142
9221
9222
Paguate
9230
9232
923-3
Boardman Trailer Park
Dixie well
Churchrock Village
White well
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35
In the Paguate-Jackpile area, three of the four wells examined
are in the Morrison Formation (Jackpile Member).
Table 6 is a compilation of published and unpublished
uranium, radium, and gross beta concentrations in ground water
for various localities in the Grants Mineral Belt. These
are largely from the ore bodies or from strata adjacent
thereto, and arc intended to show natural concentrations of
these radionuclides. Despite the wide variations, radium
rarely exceeds 10 pCi/] a'licl is commonly less than 5 pCi/1,
except in mines, or in ponds formed from mine drainage.
Dissolved uranium is also enriched in waters associated
with active mines and. can readily reach concentrations
of several hundred pCi/1. Natural background uranium levels
are difficult to estimate from the limited data, but would
appear to be on the order of 20 pCi/1 or less. Concentrations
markedly greater than the foregoing, particularly if associat-
ed with mining and milling activity, may be evidence of
degradation.
Blu cwa t e r-Mila n-Gr a n t s
The Anaconda Company mill and tailings pile is partially
bounded by cultivated areas situated in Bluewater Valley, which
contains the town of Bluewater on the western edge. Irregularly
snaped landforms northeast and east of the mill are basalt
lava flows which are also the substrate for a portion of the
tailings ponds. In nearby areas the basalt constitutes a
principal shallow aquifer. The San Andres Limestone, the
principal bedrock aquifer, also crops out in close proximity
to the ponds. Thus, there are means by which wastes from
the ponds can enter potable ground water.
The expected impacts of uranium mining and milling on
groundwater in the developed area between Bluewater and Grants
can be traced to the Anaconda Company mil]. It is also pos-
sible, but unlikely, that the United Nuclear-Homestake Part-
ners mill could adversely affect ground-water in this area.
Radium and nitrate concentrations in ground water are
depicted in Figure 5. With the exception of the Berryhill
Section 5 well (station #9121) and the Anaconda injection
well (#9021), radium-226 in both the alluvial/basalt aquifer
and in the underlying San Andres Limestone ranges from 0.06
to 0.42 pCi/1. If well #9124 is considered as a background,
-------
^$*S^#ffi
&%v5:^u^^«
\\. \ ^>^W^ \Wn'i"*ri*8^X ^ SANDY ' M. £^£V\*CTffiSI*^l
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>«^%«4jjjjhs3^^^^^^^ :J&jj>
mfa&vm&Msiii
\Vjt$aP W-1 ^^Jfe^S
Figure 4 . The Anaconda fompany Uranium Mill and
Tailings Pond-Bluewater
-------
Table 6
37
Summary of Reported Cqnconlrat ions
for Radium, Gross Beta and Natural Uranium In Ground Wator In the Grants Mineral Belt
Location
T R S Q
9 12 11 222
12 11 24 4
12 11 24 4
12 12 4 343
12 10 8 3
13 8 30 100
13 8 30 200
13 9 29 144
13 9 29 41
14 9 28 441
14 9 32 413
14 9 32 221
14 9 17 400
14 9 18 400
14 9 28 143
14 9 29 312
14 9 30 200
14 9 32 122
14 9 32 314
14 9 34 422
14 9 36 313
14 9 36 313
14 10 24 100
15 12 17 123
17 12 20 11
17 16 35 14
17 16 35 14
17 16 35 14
17 16 35 12
23 14 .3 13
Source Depth
(melers)
Paxton Spring Spring
Industrial Wei 1
Anaconda Well (Injection)
109
109
Aquifer2
Qb
Ps
Radium
pCi/l
4.3
0.4
0.36
gross
B
Bluewater Lake Surface <0.1
Well
El Paso Natural Gas Co.
El Paso Natural Gas Co.
Westvaco Mineral Development
Co.
Mine Dri ft
Wei 1
We 1 1
Mine Drift
Kermac Nuclear Fuels Corp.
Kermac Nuclear Fuels Corp.
Kermac Nuclear Fuels Corp.
Phillips Petroleum Co.
Kermac Nuclear Fuels Corp.
Homes1ake-New Mexico Partners
Homestake-New Mexico Partners
United Nuclear Company
United Nuclear Company
United Nuclear Company
Kermac Nuclear Fuels Corp.
Homestako-Sapin Partner
Crownpoi n1 Wei I 1
UNC-Nt Churchrock Mine
UNC-NE Churchrock Mine
UNC-NE Churchrock Mine
KM-Section 35, Churchrock
Mine
Gas Company Burnham Well 1
Pond In South Paguate pit
442 -.
137
174
216
224
196
168
306
457 '
372
714
457
518
549
549
1585
Pond
Pym
Jmw
Kd
Jt
Jt
Jmw
Jmw
Jmw
Kd
Jmw
Jmw
Jmw
Jmw
Jmw
Jmw
Jmw
Kd
Jmw
Jmw
Jmw
Jmw
Jmw
Jmw
Jmw
Jrnw
Jmw
0.2±0.1
8.5+1.7
2.9+0.6
5.1
5.1
1.1
10 +2
42
2.7+0.5
5.6+1.1
1.1
10 +2
2.0±0.4
42
1.1+0.2
1.4+0.3
27 +5
1.2±0.2
2.310.5
0.2+0. 1
0.05
0.62
0.09
8.10
0.24
190
36
12
150
18
37
69
39
12
49
18
9.
75
6.
56
9.
+ 5
1 2
+ 3
+ 6
+ 7
+ 2
± 4
0+1.3
11 1
5± 0.9
1 8
8± 1.4
U natural
d I ssol ved
pCi/l .
1.82
4.27
0.84
1.96
139
<.07
8.4
16.1
<0.28
185
22
847
0.05
170
1. Data sources are as follows:
Ambrosia Lake area: Cooper and John, 1968
Laguna-Paguate: Letter from F. P. Lyford, U. S. Geological Survey, WRD, Albuquerque, NM
to John Dudley, New Mexico Environmental Improvement Agency,
dated February 12, 1975.
Churchrock: Written communication from W. Hiss and T. Kelley, U. S. Geological Survey,
WRD, Albuquerque, NM to John Dudley, New Mexico Environmenlal Improvement
Agency, dated February 14, 1975.
Grants-Bluewater-Prewitt: Letter from J. M. Stow, U. S.-Geological Survey, WRD, Albuquer-
que, NM to Eugene Chavez, State Engineer Office, Roswell, NM,
dated April 14, 1961.
2. Aquifers:
Qb
Kd
Jmw
Jt
Ps
Pym
basalt flow
Dakota Fm.
Morrison Fm., Weslwater Canyon Mbr.
Tod 11 to Fm.
San Andres Ls.
Yesd Fm, Meseta Blancha Mbr.
-------
38
0.06
©124
0.8
O.26
0123
3.2
O.17
E3122
1.3
T<;i!ings
Pond
Bluewater
liftti
0.95
riAnaconda
U0.50
£2118
9.0
QUALITY OF WATER INJECTED
Period
19GO to
1S65
1966 to
1963
Radium
292
pCi/l
11DpCi/[
hSilrste
105ppm
Source
West;
1S72
MR!;
1975
O.18
©115 0.2
3.9 ell9
5.4
0.27
EI 120
0.73
O.14
©129
2.5
O.21
ra127
0.03
O.15
0128
1.4
N
>
O
4 km
O.13
0101
4.2
SCALE
O.O9
©103
5.5
Principal water bearing unit
© ALLUVIUM/BASALT
Q SAN ANDRES LIMESTONE
A GLORIETA SANDSTONE
X YESO FORMATION (injection)
Map symbols
^-radium, pCi/l
0.18""^
©127well location and identifier
3.8 >^
^ nitrate plus nitrite, mg/l
Figure 5. Radium and Mtrate Concentrations in Ground
Water in the Grants-Bluewater Area
-------
39
there is evidence of leakage from the injection zone.
Natural uranium and chloride from the monitor well (#9117),
Roundy windmill, and North well (#9122) for the period, 1969
througn 1973 are increasing with time and vary directly with
the volumes of waste injected. The concentration of polonium-210
(2.3 pCi/1) exceeds all ot'her wells in the Bluewater-Grants
area and is well above the. average of 0.33 pCi/1 for six wells
in bedrock. Concentrations of chloride and natural uranium in
the waste water average 2010 ppm arid 7340 pCi/1, respectively
for the period, 1960 to 1965 (West, 1972). Radium from 1960
through 1969 averages 221 pCi/1 (Clark, 1974). Contrary to
original projections, contamination apparently extends into
the San Andres Limestone, according to the partial chemical
data for these three monitoring wells.
Significant introduction of wastes into ground water in
the Bluewater area occurs as a result of seepage from the
tailings ponds. Past investigators noted the migration of
nitrate from the ponds (New Mexico Dept. of Public Health,
1957). Changes in the milling process greatly reduced
the nitrate content in the tailings, but seepage has con-
tinued at a rather high rate, averaging 182.9 x 106 liters
per year for 1973-1974 (Gray, 1975). The average volume
injected in the same period was 348 x 106 liters. Therefore,
the seepage:injection ratio is 0.53. In essence, one-third
of the waste stream portion not evaporated enters the shallow
aquifer. Assuming that this ratio applies to the period
1953-1960, seepage is estimated at 3200 x 106 liters or
845 million gallons. From 1953 to mid-1960, the seepage frac-
tion was probably even larger, but is unknown. Discounting
this seven-year period and assuming an average radium concen-
tration of 130 pCi/1 in the seepage, 0.4 curies of radium
entered the shallow aquifer, which is very definitely potable.
It is strongly recommended that all available chemical
data for both pre- and post-injection periods be evaluated,
together with monthly or quarterly injection volumes to fur-
ther confirm or deny the apparent trends. If the
trends shown are valid, thorough reevaluation of the
injection method of waste disposal and construction of
additional monitoring wells in the Yeso Formation and the
Glorieta-San Andres is in order. Because of low MFC values,
this is particularly true if increasing concentrations of
radium-226 are appearing in the aquifers above the injection
zone.
-------
40
Impacts of tailings pond seepage on nearby shallow
groundwater are unknown because of the inadequacy of properly
located sampling wells. Ground-water flow patterns in the
vesicular basalt and interbedded alluvium underlying the
northwest pond and portions of the main pond are not described
in the available references. Complex permeability distri-
butions and density considerations add further complications.
However, seepage is occurring and it is possible that the
Company estimates stated above are conservative.
United Nuclear-Homestakc:. Partners Mill and Surrounding Area
The mill is partially surrounded on the soutlwest
or downgradient side by housing developments and irrigated
farm lands, both of which depend on local ground-water
supplies. Also obvious in the photograph as a dark
tan band around the base of the tailings pile is extensive
seepage. This is collected and pumped back to the
pond above the sandy tailings, but seepage from the
pile proper and from the encircling moat can enter the
ground-water reservoir. The five-sided polygon adjacent
to the mill buildings is an inactive tailings pile that
was formerly part of the Komestake-New Mexico Partners
mill. In the upper left-hand portion of the photograph
is shown the terminus of the San Mateo Creek drainage
from the San Mateo and Ambrosia Lake areas .
Three distinct aquifers are present in the area of the
mill and surrounding developments. In ascending order, these
include the San Andres Limestone, the Chinle Formation, and
the alluvium. Water table conditions and a southwestward
lateral flow gradient prevail in the latter, with static water
levels about 15 meters below land surface. The San Andres
Limestone originally was under artesian head, but heavy pump-
ing for irrigation and for industry has removed much of the
head once present. Data presented by Gordon (1961) indicate
a downwind flow gradient, but the permeability of the Chinle
Formation is low and actual vertical water transfer is prob-
ably minimal. The chief significance of these hydrogeologic
conditions is that liquid effluents produced by the uranium
milling operation are likely to infiltrate at the mill site
and travel in a south-southeast direction toward the nearby
subdivisions. On the other hand, water quality in the Chinle
Formation and the still deeper San Andres Limestone is likely
to be unaffected.
-------
41
Radium concentrations-in groundwater (Figure 6) from
the San Andres and Chinle range from 0.05 to 0.27 pCi/1,
with a mean of 0.16 pCi/1 for six determinations. Realis-
tically, assuming that minimum detectable amount is 0.1
pCi/1 versus 0.05, the average increases to 0.18 pCi/1.
The peak value from shallow wells tapping the water table
aquifer in the alluvium is 1.92 pCi/1 in well D, the
mill's single active monitoring well (#9135). Although
below the standard of 3 p"Ci/l, this value does indicate move-
ment of contaminants away from the tailings pond. Attenuation
due to sorption may mask a very sharp concentration gradient
between this well and the pond. At a distance of approximately
0.6 kilometers from the ponds, radium in the shallow aquifer
reverts to levels of 0.13 to 0.72 pCi/1 and averages 0.36 pCi/1,
or about twice that present.in the bedrock reservoirs at
depth. Relatively high concentrations (0.72, 0.61 pCi/1)
in the Worthen and Enyart wells may reflect plumes or fronts
of contaminants - that have advanced ahead of the main body.
The water table map (Figure 7) prepared by Chavez (1961),
portrays an elongated, northeast-trending lobe or mound cen-
tered on the smaller tailings pile from the now inactive
Homes take-New Mexico Partners mill.
The possibility of ground-water pollution from the United
Nuclear-Homestake Partners tailings pond was noted in the
early 1960 's (Chavez, 1961). Samples from on-site monitor-
ing wells completed in the alluvium contained from 0.8 to
9.5 pCi/1 radium despite the fact that ore had been pro-
cessed for less than two years. These concentrations arc
markedly above the normal range of 0.1 to 0.4 pCi/1 in
wells several miles west of the mill and from wells in the
alluvium between San Rafael and Grants.
Chloride and TDS data for well #9107 (Figure 6) support
the idea of a tongue of contaminated groundwater in the area
between this well and the tailings pile. Heterogeneities
in sediment permeabilities, coupled.with irregular induced
flow gradients resulting from seepage return flows, make
definition of the polluted front rather difficult. It is
clear that one well (well D, #9135) is inadequate for the
task.
Selenium concentrations (see Table 3) in several of the
domestic wells located downgradient from the mill are anoma-
lously' high and are, perhaps, the best indicator of ground-
water contamination. Nearby wells (#9102, #9107, and #9113)
-------
/
42
/
Principal water bearing unit
@ ALLUVIUM/BASALT
A CHINLE FORMATION
fj SAN ANDRES LIMESTONE
Map symbols
^^> radium, pCi/l
©1C7 well location and identifier
2200/90-^
TDS/chloride, both in mg/l
/v
|i(
oi;
(
*v
&
$s
(
a
||2?00/1 10
II
II Murray
Acres
li
HOO/37,1
II
o.osl!
AH 05
L3^0!4! J|
Figure 6. Radium, IDS and Chloride in Ground Water Near
the United Nuclear-Homestake Partners Mill
-------
43
#1 Supply
© Well
#10
0120
110
6514.35
(New) Well D
#14
60°
65 _
#13
© J8Total Depth, m
651O 14Top of Chinle, m
Static water level elevation,
feet above MSL
© CASED WELL
O UNCASED WELL
65O3.25 © 69
1OO 2OO 3OO 4OO meters
BROADVIEW ACRES SUBDIVIS Of
Figure 7 . Water Table Contours and Well Locations at the
United Nuclear-Homestake Partners Mill Site
-------
44
contain from 20 to 106 times the recommended maximum sele-
nium concentration of O.Ol'mg/1 (National Academy of
Sciences-National Academy of Engineering, 1972). Two of
the wells contain approximately two-thirds of the concen-
tration in the monitor well (1.52 mg/1). The water supply
for the mill contains <0.01 mg/1, whereas the seepage
collection ponds adjacent to the presently active pile
contain 0.92 me/1. Analyses for additional wells are
in process to further define the source and extent of
the contamination.
Elevated levels of polonium-210 are present in
well D (#9135) and in other wells f#9102, #9106, #9107,
and # 9113) downgradient from a suspected contamination
front in the shallow aquifer. Whereas background for
polonium-210 is approximately 0.34 pCi/1 (Table 5), in wells
tapping the Chinle Forrnatioji and in alluvial wells removed
from suspected contamination, concentrations range from 1.0
to 2.3 pCi/1 in wells suspected to be contaminated. Maximum
values for polonium-210 are from well D (ffyiii>). The
elevated levels of polonium-210 in supply well #2 (#9134)
cannot be'explained.
Provision of an alternative water supply is strongly
recommended to avoid consumption of shallow groundwatcr
exceeding 0.01 mg/1 selenium. Deeper wells completed only
in the Chinle Formation and preferably fully cemented in
the interval from land surface to 15 meters into the Chinle
should be considered minimum.
Ambrosia Lake Area
The Kerr-McGee mill is located on the dip slope of
a southeast-facing cuesta. The area is underlain by a
thin veneer of silt and clay alluvium over the Mancos Shale.
The large network of tailings ponds and water storage
reservoirs were built by excavation and by selectively
sorting the coarse tailings for retention dams. Discharge
from numerous mines and from ion exchange plants gives
rise to perennial flow in Arroyo del Puerto which
trends north-south. Seepage from the tailings ponds and
from the aforementioned sources is evident from the vege-
tation present in the formerly dry washes. At the right
center edge of the photograph is the inactive tailings
pile at the United Nuclear Corporation mill.
-------
45
Water sampling in the Ambrosia Lake area focused on the
Kerr-McGee tailings disposal operation and the combined im-
pact of various ion exchange plant and mine water discharges
into San Mateo Creek and Arroyo del Puerto. Because of in-
fluent stream conditions, these surface water bodies repre-
sent line sources of recharge to the shallow ground-water
reservoir. The determination of impacts associated with
mine dewatering and solution mining exceeded the scope of
the study. Of the 22 wells sampled in the area (see Figure
8) all but 3 were part of the Kerr-McGee Nuclear Corporation
environmental monitoring network. The absence of sampling
points near the United Nuclear mill and tailings pile or near
the active mines and ion exchange plants precluded study in
these areas. It is obvious, however, that seepage from set-
tling ponds, from open channels leading to the two principal
streams in the area and the disposition of solutions involved
in in-situ leaching remain as unknowns.
Nevertheless, the conservative parameters clearly in-
dicate the infiltration of wastewater. Whereas shallow
ground water beneath San Mateo Creek contains about 700
mg/1 TDS in the reach above Arroyo del Puerto, the reach
below has about 2000 mg/1. Ammonia increases four fold
from 0.05 to 0.22 mg/1 and nitrite plus nitrates goes
from an average of less than 1 mg/1 to 24 mg/1. The
selenium and vanadium data do not indicate widespread move-
ment from the tailings piles. One exception is well KM-43
(#9208) which contains 0.29 mg/1 selenium as well as high
radium and TDS. The Marquez windmill (#9132) is also
enriched in selenium which further substantiates the TDS,
chloride, ammonia, and nitrate data results, i.e., con-
tamination of the shallow aquifer.
The concentration of radium in ground water in the
vicinity of the tailings piles at the Kerr-McGee mill
averages 1.7 pCi/1 for the 12 wells sampled. The highest
concentration, 6.6 pCi/1, occurs at station #9213 near the
base of the seepage catchment basin and probably character-
izes the quality of ground-water seeding beneath ami thro^h
the retention dam. Water in the basin, per se, contains""0"
65 pCi/1 radium. Note that high TDS, chloride, ammonia,
and nitrate plus nitrite appear in the seepage, but in the
adjacent ground water (stations #9207, 9213), only chloride
and TDS persist. Within 1 to 2 kilometers of the tailings
pile periphery, radium concentrations in shallow ground
water to depths of 17 meters are 4 pCi/1 or less, and average
about 1 pCi/1. The maximum concentration of 1 to 4 pCi/1
appear approximately 1.5 kilometers east of the main tailings
dam.
-------
ell United Nuclear Mill
Tailings Pond
95) (inactive)
03C40)
Storage Pond
Kerr-McGeo Mill lib
Q-GROUND-WATER SAMPLING POIMT #9201
(035)
\
Radium concentration, pCi/l
Figure 8 . Radium Concentrations in Ground Water in the
Ambrosia Lake Area
-------
47
The general pattern described is in agreement with the
migration pattern described by the Kerr-McGee staff at the
time of the field study. Despite a concentration of 65 pCi/1
in seepage from the ponds, concentrations in the immedi-
ately adjacent ground water do not exceed 6.6 pCi/1, and
quickly reduce to 4 pCi/1 or less. Seepage leaving the
property and moving southeastward parallel to Arroyo del
Puerto averages 0.47 pCi/1 radium.
Despite the relatively localized contamination of ground
water adjacent to the Kerr-HcGee tailings ponds, serious
question remains concerning their adequacy as a means of
waste disposal. Company data for 1973 and 1974 reveal that
seepage from the ponds averaged 935 liters/minute. Influent
averaged 3181 liters/minute; therefore, 29 percent of the
wastes entered the ground water and the balance evaporated.
Assuming 60 pCi/1 in the seepage and a 20-year operating
period, 0.6 curies of radium are introduced to ground water.
The company data indicate that the seepage rate was fairly
constant at 946 and 924 liters/minute for 1973 and 1974,
respectively. Also shown in the water balance is "negative"
seepage in the third quarter of each of three years (1972,
1973, 1974). This is interpreted by the company as seepage
entering the ponds. The writers consider this highly unlikely
and suggest that it is, in fact, overland flow related to
thunderstorm activity prevalent at this time of year. Re-
porting of data in this manner distorts interpretation of
the water balance for the tailings ponds by implying, in
this case, that no seepage occurred during these periods.
More importantly, the influx of overland flow into the ponds
prompts questions concerning their stability and overall
management.
Churchrock Area
The Puerco River at Gallup was ephemeral until upstream
mining operations reached a scale such that wastewater dis-
charge was sufficient to cause perennial flow. At present,
the combined discharge from the United Nuclear and Kerr-McGee
mines, located as shown in Figure 19, is about 16 x 106
liters/day, and characterized by 8 to 23 pCi/1 radium,
700 to 4900 pCi/1 uranium, 0.01 to O.JD4 mg/1 selenium, and
0.4 to 0.8 mg/1 vanadium. In terms of radium, selenium and
vanadium, the water is unfit for stock or potable uses and
not recommended for irrigation. Infiltration of the mine
wastewater could threaten potable ground water in the vicinity
of the Puerco River and possibly the Gallup municipal supply.
In part., the present "study examines whether noticeable ground-
water quality deterioration has occurred to date.
-------
48
NAVAJO INDIAN RESERVATION
J20
012
-------
48
In this setting, sampling in the Churchrock area in-
volved 13 wells located along the Puerco River, South Fork
Puerco River and, for control purposes, an adjacent water-
shed tributary to the Rio Puerco. A single sample from a
newly developed well serving the Gallup area was also tested.
The sampling points included water used for stock, domestic
use, and for public drinking water supplies. Alluvial and
bedrock aquifers were sampled in an area of 200 km2 located
generally east and northeast of Gallup.
None of the ground-water samples contain sufficient
quantities of naturally occurring radionuclides to constitute
a health problem. The radiochcmical, trace element and
gross chemical data do not indicate that contamination of
ground water is occurring as a result of the mining opera-
tions underway. More suitably located sampling points,
together with revised analytical programs are strongly
recommended improvements to the existing industrial efforts.
By comparison, the effects of mining on the concentration
of radium in ground water are pronounced. Present discharge
from the Kerr-McGee mine, which is in the development versus
mining stage, averages 7.9 pCi/1 as compared to 23.3 pCi/1
for the United Nuclear mine. The latter is producing ore.
In both cases, elevated radium concentrations are present.
In large part, these are attributable to mining operations
and practices and do not represent natural water quality,
evident from samples of ground water collected from 4 wells
and 3 long holes, all in the Westwater Canyon Member (Hiss
and Kelley, 1975). Radium varied from 0.05 to 0.62 pCi/1
compared to 0.28 to 184.8 pCi/1 uranium. An additional
sample collected in November 1973 from the settling pond
discharge at the United Nuclear mine contained 8.1 pCi/1
radium and 847 pCi/1 natural uranium. Thus, initial pene-
tration of the ore body increased radium at least 10-fold
and subsequent mine development work over a two-year period
resulted in another three-fold increase. Compared to
.natural concentrations, radium increased some 23 times and,
if similar trends seen in the Ambrosia Lake area prevail,
ultimate radium concentrations on the order of 50 to 150
pCi/1 are likely.
-------
49
Jackpile-Paguate Area
Sampling in the vicinity of the Jackpile-Paguate open
pit uranium mine included four wells located as shown in
Figure 10- One of these (#9233) is the Pa^uate municipal
supply which is a. flowing arte'sian well completed in*"allu-
vium at a depth of 22.9 meters. The remaining three wells
are property of the Anaconda Company and are used for potable
supply and for equipment washing, etc. It is believed that
all three were former exploration holes that have been
reamed out, cased, and equipped with a submersible pump.
The water quality is probably representative of the Jackpile
Sandstone Member of the Morrison Formation, which also is
the principal ore body in the Laguna mining district.
Dissolved radium in water from the Jackpile Sandstone
aquifer ranges from 0.31 to 3.7 pCi/1. The latter value is
from the new shop well which is a source of potable and
nonpotable water for the facility. Consumption should be
discontinued because the radium exceeds the drinking water
standard of 3 pCi/1.
The village of Paguate water supply is well below the
recommended maximum level for not only radium, but also the
other isotopes considered in the present study. Selenium,
however, is at the maximum recommended level of 0.01 mg/1.
It is extremely unlikely that the present shallow-well
supply will be affected by mining unless the open pit was
extended close to the well field. Recharge to the shallow
aquifer is derived from runoff which infiltrates to the west
and north. After percolating southward, it then reappears
in a marshy area west of the village. Springs and artesian
conditions are likely the result of decreasing transmissivity
due to the near surface occurrence of shales and poorly per-
meable sandstones in the lower reaches of Pueblo Arroyo.
The downstream impacts of the Jackpile-Paguate mine
on ground water were not determined because of the absence
of suitable sampling points. It is recommended that shal-
low monitor wells be installed at several points along the
Rio Paguate to ascertain the chemical, radiochemical, and
trace element species present. Limited coring in the
sediment-filled Paguate reservoir would provide data on
variations in the radium and uranium content before and
during mining. Such data would also provide information on
radioactivity associated, with sediment transport during
periods of peak runoff and erosion.
-------
50
i-\?T
PaguateV'"
T 11 N
Anaconda Co.
Jackpile-Paguate
Open Pit
Paijuata Reservoir
I-40
230
© GROUND-WATER SAMPLING POINT #9230
(0.6)
N Radium concentration, pCi/l
10. Radium Concenti a.Lions in Hround 'Vater in the
Paguate-Jackpile Area
-------
51
Significance of- Radic>_logicjxl Data
Regulations and Guidelines
On August 14, 1975, the U.S. B.P.A. published in the
Federal Register (40 FR1SS, p. 34323-34328) a "Notice of
Proposed Maximum Contaminant Levels for Radioactivity" to
be included in 10 CFR Part 141 - Interim Primary Drinking
Water Regulations. The following are the proposed maximum
contaminant levels for radium-226, radium-228 and gross
alpha particle radioactivity:
(1.) Combined radium-226 and radium-228 not to exceed
5 pCi/1
(2.) Gross alpha particle activity (including
radium-226, but exclusive of radon and uranium contents)
not to exceed IS pCi/1
The proposed regulations also discuss maximum contaminant
levels of beta particle and photon radioactivity from
man-made radionuclides.
Therefore, with respect to these proposed radioactive
contaminant levels, the following conclusions may be ob-
tained from this study:
1.) Additional analysis for radium-228 and lead-210
will proceed and be reported in a separate report at a
later date.
2.) Since radium-228 is a daughter product of
thorium-232, and thorium analyses of these waters fluctuated
around background concentrations, it appears that the
radium-228 content should also be at background levels;
i. e., less than 0.02 pCi/1; hence, the radium-228 content,
under assumed equilibrium conditions, should be less than
0.042 pCi/1, the highest reported thorium-232 content.
3.) Only two locations, out of the 71 ground water
locations sampled, have radium-226 concentrations in excess
of 5 pCi/1. The proposed new standard of 5 pCi/1, combined
radium-226 and radium-228 contents, is therefore exceeded
at these two locations.
4.) Sixty (60) of the 71 ground water locations had
gross alpha results in excess of the proposed 15 pCi/1
limit'; however, the gross alpha results reported here include
uranium isotopes. Included in the list of sixty locations
-------
52
are several locations where the gross alpha results are less
than 15 pCi/1, but consideration of the 2 sigma confidence
level would then indicate a gross alpha possibly in excess
of the 15 pCi/1 limit.
5.) The proposed maximum gross beta limit excludes
naturally occurring radionuclides (e.. g., lead-210) ; there-
fore, there is no presently proposed maximum contaminant
level for lead-210; and the NMEIA population guide MFC of
33 pCi/1 appears to be the only current applicable guide-
line for lead-210 content.
Since the above radioactivity contaminant levels are
proposed and not final interim primary drinking water
regulations, the following discussions of the radiological
analyses of water samples obtained during this study will
be based on the U.S.P.H.S. Drinking Water Standards (1962)
and current NRC/NMEIA maximum permissible concentration
levels.
Radium-226
Of the 71 ground-water sampling locations of this
study, only 6 locations showed radium-226 concentrations
in excess of the 3.0 pCi/1 drinking water standard
(U.S.P.H.S. Drinking Water Standards, PUS Publication
Mo. 956; 1962). The population guide--maximum permis-
sible concentration (10CFR, Part 20, Table II, column 2,
unrestricted areas) is 10 pCi/1. Table 12 lists the 6
locations and presents the gross alpha and radium-226
results based on NEIC laboratory analysis.
The Jackpile-New Shop Well, Paguate (#9232), is
a potable water supply having a radium concentration in
excess of the drinking water standard. This water need
not be used for human consumption since other nearby wells
have much lower radium concentrations (e.g., the Paguate
municipal supply (#9233) or the Jackpile Well (#9230)).
The Phil Harris Well, Grants (#9201), is the
only other potable water supply with a radium concentra-
tion in excess of 3.0 pCi/1. The Berryhill Section 5
Windmill, Bluewater (#9121), is used as a stock water
supply; and since there are no nearby human consumers, the
radium concentration of 6.3 ± 0.1 pCi/1 is of no immediate
health hazard.
Two of the Kerr-McGee monitor wells, samples from KM-43
(#9208) and KM-B-2 (#9213), also had radium levels in excess
of 3.0 pCi/1. Stable inorganic species in the water also
render it unfit for human consumption. In addition, the well
is not in use for water supply and therefore does not present
a health hazard.
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53
Sample #9212, a surface water sample, obtained from
the seepage collection pit at the base of the Kerr-McGee
tailings pond, had a radium concentration of 4.9 pCi/1.
However, this water is certainly not fit for human con-
sumption nor is it used as a livestock or irrigation
supply.
For comparison purposes, Table 8 shows the radium
concentrations for municipal water supplies surveyed dur-
ing this study.
A radium concentration of Or68 pCi/1 from the Erwin
Well, Gallup (#9233) was the highest radium concentra-
tion for the municipal supplies. It appears that, on
the whole, municipal water supplies in the Grants Mineral
Belt area do not exceed 23% of the drinking water standard
of 3.0 pCi/1.
Ten privately owned, potable water supplies were
surveyed in the Murray Acres-Broadview Acres and other
areas surrounding the United Nuclear-Homestake Partners
mill. The highest radium concentration was 0.72 pCi/1
at the IVorthen Well (# 9107), and the lowest concentra-
tion was less than 0.05 pCi/1 at the Schwagerty Well
(#9105). The average radium concentration for these
10 private wells was 0.26 pCi/1.
Six privately owned, potable water supplies in the
Ambrosia Lake area contain 0.07 to 3.6 pCi/1. Of nine
privately owned potable water supplies surveyed in the
Grants-Bluewater area, the maximum radium concentration
was 0.24 pCi/1. Only two privately owned wells were used
solely as potable water supplies in the Gallup area. These
were the Hassler (#9139) and Boardman (#9138) residences.
The radium concentrations at these two locations were 0.22
and 0.64 pCi/1, respectively. The other 8 wells in the
Gallup-Churchrock area were used mainly as stock water
supplies and had an average radium concentration of 0.35
pCi/1.
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54
Table 7
Locations with Radium-226 in Excess of
the PUS Drinking Water Standard *
Location
Description
'9121-Berryhill
Section 5
Bluewater
/9201-P. Harris
Grants KM- 4 6
(9208-KM-43
Grants
J9212-KM Seepage
Return-Grants
/9213-KM-B-2
Grants
?9232-Jackpile-
New Shop Well
Paguate
2
£a_d i urn - 22^^^
DissoTvetTTywo Sigmn
pCi/1 ! pCi/1
6.3
3.6
4.0
4.9
6.6
3.7
oil
0.1
0.1
0.1
0.1
0.08
£ross A
DissoTv'etf
pCi/1
12
110
49
112,000
8
18
2
Ipha
lwcr*"S*igina
pCi/1
14
40
35
3,000
32
13
Remarks
Windmill Stocl
Feed Water
Potable Water
Supply
Monitor Well
Surface Water
Sample
Monitor Well
Potable Water
Supply
1 PHS Drinking Water Standard, 1962, is 3.0 pCi/1 for Radium-226.
2 Radium and gross alpha analysis by NEIC-Denver.
Radium
Table e
Concentrations for Municipal Water Supplies
Location
Description
#9112-Grants
City Hall
#9116-Milan City
Well HI
S912S-LDS
Blucwater
#9137-Erwin Well
Gallup
#9233-Municipal Well
Paguate
Village"*"
Radium- 226
Dissolved
pCi/1
0.42
0.14
0.22
0.68
0.18
0.1 2
Two Sigma
pCi/1
0.02
0.01
0.01
0.03
0,02
0.01
Gross Alpha
Dissolved
pCi/1
19
12
8
10
2
3
Two Sigma
pCi/1
13
10
10
9
4
7
1 Radium and gross ajpha results by NEIC-Denver.
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55
»
Other RadionucljLd.es
Table 9 entitled "Maximum Permissible Concentrations
in Water" presents the unrestricted area - MFC and the popu-
lation guide - MFC for selected radionuclides. The PHS
drinking water standard of 3 pCi/1 for radium-226 is more
restrictive than the population guide - MFC; therefore,
the radium content evaluations were based on the 3 pCi/1
drinking water standard. ..The other radionuclide content
evaluations are based on-the soluble MFC value since fil-
tered ground-water samples were analyzed. The MFC values
listed are from the NRG regulations which are also con-
sistent with the NMEIA regulations (June 16, 1973).
Only 3 potable water supplies had complete isotopic
uranium analysis - Wilcox (#9102), Enyart (#9133) and Dixie
Well (#9140). The highest reported results (for the Wilcox
Well) indicate less than 0.1%, 0.002% and 0.061 of the
population guide - MFC for uranium-234, uranium-235, and
uranium-238, respectively.
Of all the potable water supplies analyzed for thorium-230,
the Worthen Well (#9107) had the highest concentration of
0.99 pCi/1, less than 0.151 of the population guide - MFC.
The Meador Well (#9113) had the highest thorium-232 content
of 0.042 pCi/1 and polonium-210 content of 2.3 pCi/1 which
are, respectively, 0.006% and 0.98% of the population
guide - MFC.
All 6 municipal water supplies were analyzed for
thorium-230, thorium-232, and polonium-210. The highest
thorium-230 content was for Grants (#9112), with 0.046
pCi/1 (0.007% population guide - MFC). The highest
thorium-232 content was for the Churchrock Village, with
<0.016 pCi/1 (0.002% of the population guide - MFC). The
highest polonium-210 content was for t^e Municipal Well
at Paguate (#9233) with 0.39 pCi/1 (,0.17% of the population
guide - MFC). The Paguate sample (#9233) also had the
highest lead-210 content of less than 8.7 pCi/1 (26.36%
of the population guide - MFC).
In summary, exclusive of the radium-226 content, the
highest isotopic uranium and thorium, polonium-210, and
lead-210 contents for any potable water supply in the Grants
Mineral Belt area is less than 28.08% of the total radio-
nuclide population guide - MFC.
It, therefore, seems appropriate to conclude that for
routine monitoring of potable water supplies, isotopic
uranium and thorium, polonium-210, and radium-228 analyses
are not necessary. Accurate radium-226_and lead-210 analyses
/ 1 1 * *t 1 .4- 1 __ f. n * -I »- £ r*. ~"»«» rt, 4- -i r* *> J- n -y ^» *"i *-3 "I O ' OTT ^"* 1 I
for eacu sample yield LJJ.C. mo^u J..iJLuijpo.L.j.on xor i 0.^.10^0^-^^.
evaluations of drinking water conditions.
-------
56
Table- 9
Maximum Permissible Concentrations in Water '
(Above Natural Background)
Radionuclide
Appendix B
Table II, Column 2 Population Guide^
(Unrestricted Areas) pCi/1
pCi/1
2 2
2 2
2 1
2 1
2 3
2 3
2 3
2 3
2 3
u-
6 Ra
8 Ra
0 Po
0 Pb
0 Th
2 Th
* U
5 U
8 U
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Soluble
Insoluble
Natural
Soluble
Insoluble
30
30
30
200
2
30
2
40
30
30
30
30
40
40
30
30
30 -
,000
30
,000
700
,000
100
,oao
,000
,000
,000
,000
,000
,000
,000
,000
,000
,000
,000
,000
10
10
10
66
10
13
10
10
10
10
13
13
10
10
io3
,000
10
,000
233
,000
33
,667
667
,000
667
,333
,000
,000
,000
,000
,333
,333
,000
,000
1 lOCFR-Part 20--Standards for Protection Against Radiation--
U.S.N.R.C. (April 30, 1975).
2 .Population Guide = 1/3 times Unrestricted Area
MFC--Table II Values.
' ' O O f '
3 A maximum permissible concentration of 3.33 pCi/1 for Ra
is the Handbook 69 population guide (i.e., l/30th of the
HB69 continuous occupational exposure limits).
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57
REFERENCES CITED
-Bond, A. L., 1975, N. Mexico Environmental Improvement Agency,
Letter of February 14, 1975, to J. .Thornhill, U.S. Envi-
ronmental Protection Agency, Region VI, 2 p.
Chavez, E. A., 1961, Progress report on contamination of
potable groundwater in the Grants-Bluewater area, Valencia
County, New Mexico: N. Mexico State Engineer Office,
Roswell, New Mexico.
Clark, D. A., 1974, State of -the art - uranium mining, milling,
and refining industry: U.S. Environmental Protection
Agency, Office of Research and Development, Corvallis,
Oregon, Technology Series, Report No. EPA-660/2-74-038,
113 p.
Cooper, James B. and Edward C. John, 1968, Geology and ground-
water occurrence in Southeastern McKinley County, New
Mexico: N. Mexico State Engineer, Technical Report 35,
prepared in cooperation with the U.S. Geological Survey,
108 p.
Dinwiddie, George A., W. A. Mourant, and J. A. Easier, 1966,
Municipal water supplies and uses, Northwestern New Mexico:
N. Mexico State Engineer Technical Report 29C, prepared
in cooperation with the U.S. Geological Survey, 197 p.
Dudley, John, 1975, Water Quality Division, the N. Mexico
State Health and Social Services Department, July 15
memorandum reply to Robert Kaufmann, Office of Radiation
Programs, U.S. Environmental Protection Agency.
-Button, C. E., 1885, Mount Taylor and the Zuni Plateau: rn
the Sixth Annual Report of the U.S. Geological Survey,
1884-85, p. 113-198.
- Fenneman, N. M., 1931, Physiography of western United States:
New York, McGraw Hill, 534 p.
-Gordon, Ellis D-. , 1961, Geology and ground-water resources
of the Grants-Bluewater area, Valencia County, New Mexico:
N. Mexico State Engr. Technical Report 20, prepared in
cooperation with the U.S. Geological Survey, 109 p.
-------
58
Gray, W. E., 1975, Environmental Engineering, N. Mexico Oper-
ations, Uranium Division, The Anaconda Company, February 14
letter to Robert F, Kaufmann, U.S. Environmental Protec-
tion Agency, ORP, Las Vegas, Nevada, response to request
for data.
Hilpert, Lowell S., 1963, Regional and local stratigraphy of
uranium-bearing rocks:' N. Mexico State Bureau of Mines
and Min. Res. Memoir 15, p. 6-18.
John, Edward C., and S. W. West, 1963, Ground water in the
Grants District: in_ N. Mexico State Bureau of Mines and
Min. Res. Memoir 15, p. 219-221.
Keefer, D. H., 1974, Radiological Evaluation of Region VI
National Pollution Discharge Elimination System Permits:
unpublished briefing statement, U.S. Environmental Pro-
tection Agency, Region VI, Dallas, Texas, 9 p.
Kelley, Vincent C., ed. , 1963, Tectonic setting: i_n N. Mexico
State Bureau of Mines and Min. Res. Memoir 15, p. 19-20.
Kittel, Dale F., Vincent C. Kelley, and Paul E. Melancon,
1967, Uranium deposits of the Grants Region: in the New
Mexico Geological Society Eighteenth Field Conference,
Guidebook of the Defiance-Zuni-Mt. Taylor Region of Ari-
zona and New Mexico, p. 173-183.
Midwest Research Institute, 1975, A study of waste generation,
treatment and disposal in the metals mining industry:
Review draft of Final Report, Contract No. 68-01-2665
for Office of Solid Waste Management, U.S. Environmental
Protection Agency, Washington, DC, 2 vol., 520 p.
National Academy of Sciences --National Academy of Engineering,
1972, A Report of the Committee on Water Quality Criteria:
Environmental Studies Board, at the request of and funded
by U.S. Environmental Protection Agency, 594 p.
New Mexico Department of Public Health and U.S. Public Health
Service, 1957, Report of an investigation of ground water
pollution, Grants-Bluewater, New Mexico.
New Mexico Environmental Improvement Agency, 1973, Regulations
for governing the health and environmental aspects of
radiation: New Mexico Environmental Improvement Agency,
Santa Fe, New Mexico.
-------
59
Public Health Service, U.S. Dept. of Health, Education, and
Welfare, 1962, Drinking water standards--1962: PHS Publi-
cation No. 956, 61 p.
Tsivoglou, E. C., and R. L. 0'Connell,. 1962, Waste guide for
the uranium milling industry: U.S. Dept. of Health, Educa-
tion, and Welfare, Tech. Report W62-12, Cincinnati, Ohio, 78 p
U.S. Atomic Energy Commission, 1974, The Nuclear Industry:
U,S. Atomic Energy Commission, Washington, DC, WASH-1174-74,
p. 39-45.
U.S. Environmental Protection Agency, 1974, Compliance moni-
toring procedures: Office of Enforcement, National Field
Investigations Center, Denver, Colorado, 37 p.
U.S. Geological Survey, 1975, Unpublished data, New Mexico
District.
U.S. Geological Survey, 1975, unpublished data received via
written communication from WRD, New Mexico district,
Albuquerque, file number 08350500.
U.S. Nuclear Regulatory Commission, 1975, Standards for pro-
tection against radiation: 10CFR, Part 20 (April 30, 1975).
University of New Mexico, Bureau of Business Research, 1972,
"New Mexico Statistical Abstract, 1972."
-West, S. W. , 1972, Disposal of uranium-mill effluent by well
injection in the Grants area, Valencia County, New Mexico,
U.S. Geological Survey Professional Paper 386-D, prepared
in cooperation with the N. Mexico State Engineer office
and the U.S. Atomic Energy Commission, 28 p.
-------
86
CHLORIDE, ppm
S
H
,C X
M -P
H
OJ r-4
H rt
> ^
O'
-O
C
rH -H
(1) C3 ^
+-> 10 O
V) C -t-)
H O
-XJ
J_j £* ^_J
rt o u
E O (D
£ CO rH
3 £ o
tO «< C/5
bO
H
'Q3iD3rNI 3WH1OA 30V83AV
-------
87
r _ * *
liters/minute. The plant manager at the time expected
that slimes in the waste would seal the bottom of the
lagoon in about a year. However, the present loss rate
of 347 liters/minute from a ponded area of about 14.4
hectares shows that leakage continues.
As of May 1957, two wells in the shallow aquifer and
three in the deep (San Andres-Limestone) aquifer had nit-
rate concentrations of 66 to 84 mg/1 (15-19 mg/1 N03-N)
and elevated nitrate levels were present as far as 10
kilometers downgradient from the lagoon or 4.5 kilometers
from the Grants supply wells. At the present time, the
maximum nitrate concentrations in the bedrock and alluvial
aquifers within 4 kilometers of the ponds are 39 and 17.3
mg/1. Concentrations in two wells midway between the ponds
and Grants average 21.5 mg/1. In the 1956 study it was
concluded that high nitrate within 4.5 kilometers of Grants
was a result of waste disposal. This would imply movement
of 10 kilometers in 2 to 3 years, which is extremely unlikely
Available nitrate (expressed as nitrate), TDS, chloride,
sulfate and gross alpha data from the foregoing study, from
the Anaconda Company (Gray, 1975) and from the present in-
restigation were plotted to determine changes in ground-
rwater quality with respect to distance from the tailings
ponds and with time. There is a general lack of marked
deterioration in ground-water quality with time and, with
the exception of gross alpha, there is close agreement
between the company data and those from the present study.
For example, the Fred Freas well (#9127) completed in al-
luvium and the Mexican Camp well (#9120) which taps the
San Andres Limestone show essentially no change in TDS,
sulfate, chloride, or nitrate for the period 1956 to 1975.
The slight decline in TDS in the Fred Freas well is con-
trary to what would be expected if gross contamination was
present. However, the similarity between gross alpha and
sulfate fluctuations for the Mexican Camp well suggest that
wastes are within the well's area of influence.
The selenium, vanadium, and total dissolved solids ('!].'?)
data for the Bluewater-Grants area generally substantiate
the foregoing interpretation and hint at the possibility of
contamination of the alluvial aquifer. Selenium ranges from
less than 0.01 mg/1 to 0.02 mg/1, with most values being
0.01 or less. Vanadium ranges from 0.3 to 1.3 mg/1 and is
lowest in the Anaconda monitor well (#9117). Concentrations
for seven wells adjacent to the Anaconda mill,and tailings
ponds average 0.89 mg/1, which is two to three times higher
than the average for the remainder of the study area (see
'Table yj. it is suspected that these elevated levels are
indicative of contamination, but they may simply reflect
the normal concentration of vanadium in the alluvial and
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87A
San Andres Limestone aquifers. Water supply well #2 at the
'United Nuclear-Homestake Partners mill is"also completed in
this formation and contains 1.3 mg/1. Additional sampling
is recommended to characterize background and contaminated
levels before definite conclusions are drawn. With the
exception of the Jack Freas well (#9129), which is used for
domestic supply, the selenium and vanadium concentrations
are within recommended drinking water standards.
Chloride and IDS trends are not well defined. The range
for IDS is from 490 mg/1 (Mexican Camp) to 2300 mg/1 (Monitor
well), whereas chloride varies from 6.2 to 270 mg/1. The
peak chloride value of 270 mg/1 is from Anaconda well #2
(#9118) which also contains 1900 mg/1 TDS. Nearby wells in
the San Andres Limestone (#.9119, #9120, and #9126) average
823 mg/1 TDS and 54 mg/1 chloride. Cones of depression
created by the Anaconda wells may induce downward movement
of wastewater in the alluvial aquifer. Farther north, TDS
and chloride in the San Andres-Glorieta interval averages
2067 mg/1 and 6.5 mg/1. If the increase in TDS is from
purely natural causes, chloride would be expected to rise,
hence the increase in TDS and'decline in chloride may be
indicative of contamination.
Sulfate, TDS, and gross alpha in North well (#9122)
and in the Monitor well (#9117) are increasing slightly
with time. For North well, TDS increased at a rate'of
about 13 mg/1 per year and has gone from 1680 mg/1 in June
1956 to 1900 mg/1 in February 1975. Gross alpha is appar-
ently increasing about 0.1 pCi/liter per year, but the
company analytical results of about 2 pCi/1 are markedly
below the 30 pCi/1 reported herein.
The EPA gross alpha data reported herein for all of the
wells in the vicinity of the Anaconda mill are generally
15 to 20 times greater than company results. Although only
the latter are useful for defining long-term trends, the
disparity of analytical results warrants further work to
determine absolute versus relative concentrations and trends.
Of note is the fact that the February 1975 gross alpha data
for both wells exceed the proposed 15 pCi/1 limit for potable
water supplies.
At the present time, ground water developed for potable
use does not appear to be adversely affected by the Anaconda
disposal practices. This conclusion is based on analyses
for seven wells (#'s 9118, 9119, 9124, 9125, 9126, 9127,
-------
87B
completed in bedrock and in alluvium and generally
peripheral to and within 4 kilometers of the tailings
ponds. Anaconda supply wells #2 and #4, which show slightly
increasing trends for IDS, chloride, or sulfate, are closest
to the ponds and are used for potable and mill feed purposes.
For the remaining wells, increasing and decreasing trends for
IDS and sulfate are present whereas chloride, nitrate and
gross alpha results are rather- stable".
In summary, the interpretation of ground-water quality
offered by the New Mexico Health Department (1957) is not
supported by subsequent data. Concentrations of nitrates
and chloride, in particular, are not markedly different today
than in the base period from 1953 to 1956. Data for the period
from 1956 to 1969 may bear out the earlier predictions of
gross contamination, but if so, water quality since 1969 is
only slightly changed. For i^idespread ground-water con-
tamination to quickly occur from 1955 to 1956 and then rapidly
attenuate is very unlikely considering the dynamics of ground-
water flow and the continuing history of waste disposal.
Whether the earlier data were faulty or ^^^ere misinterpreted
is a matter ^of conjecture.Ground-water flow patterns in the '
vesicular basalt and interbedded alluvium underlying the
northwest pond and portions of the main pond are'not described
Ln the available references. Complex permeability distri-
butions and density considerations add further complications.
However, seepage is occurring and it is possible that the
Company estimates stated above are conservative.
The foregoing comments do not imply that ground-water
contamination is absent. Gross contamination of nearby wells,
or a continuation of the earlier, perhaps erroneous pre-
dictions of contamination, is not apparent. The major
qualification of these conclusions is that wells properly
located and completed for sampling purposes are not avail-
able, hence, the extent of contamination is not well under-
stood. Contamination is evident in the North and Monitor
wells but is not_yet a problem. Available chemical data
for pre- and post-injection periods should be evaluated.
together with monthly or quarterly injection volumes to fur-
there confirm or deny the trends shown in Figure 12. If
the trends shown are valid, thorough reevaluation of the
injection method of waste disposal and construction of addi-
tional monitoring wells in the Yeso Formation and the
Glorieta-San Andres is in order. Because of low MFC values,
this is particularly true if increasing concentrations of
radium-226 (and possibly lead-210) are appearing in the
aquifers above the injection zone.
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88
United Nuclear-Homestake Partners Mill and Surrounding Area
As shown in Figure 13, the mill is partially surrounded
on the southwest or downgradient side by housing develop-
ments and irrigated farm lands, both of which depend on
local ground-water supplies. Also obvious in the photograph
as a dark tan band around the base of the tailings pile
is extensive seepage. This is collected and pumped back
to the pond above the sandy tailings, but seepage from the
pile proper and from the encircling moat can enter the
ground-water reservoir. The five-sided polygon adjacent
to the mill buildings is an inactive tailings pile that
was formerly part o'f the Honiestake-New Mexico Partners
mill. In the upper left-hand portion of the photograph
is shown the terminus of the San Mateo Creek drainage
from the San Mateo and Ambrosia Lake areas.
Three distinct aquifers are present in the area of the
mill and surrounding developments. In ascending order, these
include the San Andres Limestone, the Chinle Formation, and
the alluvium. Water table conditions and a southwestward
lateral flow gradient prevail in the latter, with static water
levels about 15 meters below land surface. The San Andres
Limestone originally was under artesian head, but heavy pump-
ing for irrigation and for industry has removed much of the
head once present. Data presented by Gordon (1961) indicate
a downwind flow gradient, but the permeability of the Chinle
Formation is low and actual vertical water transfer is prob-
ably minimal. The chief significance of these hydrogeologic
conditions is that liquid effluents produced by the uranium
milling operation are likely to infiltrate at t-he mill site
and travel in a south-southeast direction toward the nearby
subdivisions. On the other hand, water quality in the Chinle
Formation and the still deeper San Andres Limestone is likely
to be unaffected.
-------
HOa
Significance of Radiological Data
Regulations and Guidelines
On August 14, 1975, the U.S. E.P.A. published in the
Federal Register (40 FR158, p. 34323-34328) a "Notice of
Proposed Maximum Contaminant Levels for Radioactivity" to
be included in 10 CFR Part 141 - Interim Primary Drinking
Water Regulations. The following are the proposed maximum
contaminant levels for radium-226, radium-228 and gross
alpha particle radioactivity:
(1.) Combined radium-226 and radium-228 not to exceed
5 pCi/1
(2.) Cross alpha particle activity (including
radium-226, but exclusive of radon and uranium contents)
not to exceed 15 pCi/1
The proposed regulations also discuss maximum contaminant
levels of beta particle and photon radioactivity from
man-made radionuclides.
Therefore, with respect to these proposed radioactive
contaminant levels, the following conclusions may be ob-
tained from this study:
1.) Additional analysis for radium-228 and lead-210
will proceed and be reported in a separate report at a
later date.
2.) Since radium-228 is a daughter product of
thorium-232, and thorium analyses of these waters fluctuated
around background concentrations, it appears that the
radium-228 content should also be at background levels;
i. e., less than 0.02 pCi/1; hence, the radium-228 content,
under assumed equilibrium conditions, should be less than
0.042 pCi/1, the highest reported thorium-232 content.
3.) Only two locations, out of the 71 ground water
locations sampled, have radium-226 concentrations in excess
of 5 pCi/1. The proposed new standard of 5 pCi/1, combined
radium-226 and radium-228 contents, is therefore exceeded
at these two locations.
4.) Sixty (60) of the 71 ground water locations had
gross alpha results in excess of the proposed 15 pCi/1
limit; however, the gross alpha results reported here include
uranium isotopes. Included in the list of sixty locations
-------
HOb
are several locations where the gross alpha results are less
than 15 pCi/1, but consideration of the 2 sigma confidence
level would then indicate a gross alpha possibly in excess
of the 15 pCi/1 limit.
5.) The proposed maximum gross beta limit excludes
naturally occurring radionuclid.es (e. g., lead-210); there-
fore, there is no presently proposed maximum contaminant
level for lead-210; and the NMEIA population guide MFC of
33 pCi/1 appears to be the only current applicable guide-
line for lead-210 content.
Since the above radioactivity contaminant levels are
proposed and not final interim primary drinking water
regulations, the following discussions of the radiological
analyses of water samples obtained during this study will
be based on the U.S.P.H.S. Drinking Water Standards (1962)
and current NRC/NMEIA maximum permissible concentration
levels.
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