PR-6
STREAM SURVEYS IN VICINITY OF URANIUM MILLS
IV. AREA OF SHIPROCK, NEW MEXICO - NOVEMBER 1960
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Region VIII
Denver, Colorado
Colorado River Basin Water Quality Control Project
December 1962
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ACKNOWLEDGMENT
The generous cooperation and assistance of the following are
gratefully acknowledged:
J. W. Hernandez of the New Mexico Department of Public Health;
Richard Navarre of the New Mexico Department of Game and Fish; L.
McElfresh and W. Lancaster, San Juan County Health Unit, Farmington,
New Mexico; F. Singleton of the U. S. Geological Survey, Mexican Hat,
Utah; and W. H. Scoggins, U. S. Bureau of Mines Helium Activity,
Shiprock, New Mexico for assisting in the conduct of the field survey.
J. A. Maxwell and F. Hanagarne of Kerr-McGee Oil* Industries,
Shiprock, New Mexico for assistance in collecting the samples at the
Shiprock uranium mill.
All U. S. Public Health Service personnel who participated in
the field survey and provided assistance in preparation of this report.
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STREAM SURVEYS IN VICINITY OF URANIUM MILLS
IV. AREA OF SHIPROCK, NEW MEXICO - NOVEMBER 1960
INTRODUCTION AND BACKGROUND
This report contains the findings of an eight-day field survey of
stream conditions in the San Juan River below Shiprock, New Mexico, under-
taken during November 15-23, 1960. The field study was conducted by the
Colorado River Basin Water Quality Control Project in cooperation with the
Division of Water Supply and Pollution Control, US PHS, Region VII, and the
New Mexico Department of Public Health. This survey followed a brief
investigation in August-September 1960 in connection with the accidental
release of a relatively large volume of highly toxic acid waste from the
Kerr-McGee Oil Industries uranium mill at Shiprock on August 22-23, 1960 (1).
A request was made by the New Mexico Department of Public Health on October
14, 1960 to the Public Health Service to undertake a detailed investigation
of the quality of river water downstream of the Shiprock uranium mill. The
purpose of this investigation was two-fold; to ascertain the residual
effects of the August 1960 spill and to evaluate the long-term conditions
resulting from seepage to the river in the vicinity of the uranium mill.
High river stages during October 1960 necessitated postponement of the
survey until November, when the river was low enough to permit the collection
of sediment and biological samples.
GENERAL FEATURES OF MILL PROCESS AND AREA
The town of Shiprock, as illustrated in Figure 1, is located within
the Navajo Indian Reservation in the northwest corner of New Mexico, approxi-
mately 30 miles west of the city of Farmington. The Kerr-McGee uranium mill
is situated on a low bluff on the south bank of the San Juan River a short
distance upstream and across the river from the town of Shiprock.
Operation of the Kerr-McGee uranium mill began in 1954. The plant
was processing from 400 to 500 tons of ore per day at the time of the survey.
The mill process, in brief, consists of acid leaching, solvent extraction,
stripping from the solvent, precipitation, and filtration of the uranium.
The final product is U30g, known as "yellow cake." A complete description
of the process is given in Appendix A.
Another significant industrial activity at Shiprock is the U. S.
Bureau of Mines Navajo Helium Plant, which began operations in 1944. The
Helium Plant is located approximately one-half mile below the uranium mill
and on the same side of the river.
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FIGURE I
SHIPROCK, N. MEX.
AND GENERAL AREA
COLORADO RIVER
BASIN PROJECT
NOVEMBER, I960
@) Sampling Locations
Scale I in = 2 miles
"i
a:
m
x
o
CD
CD
Shiprock
Irrigation
/ Canal
To Farmingtnn
Kerr McGee
Uranium Mill
-1 >
, r ToGallup
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- 2 -
Other activities in the area include extensive oil and gas exploration
and some agricultural interests, mostly upstream from Shiprock.
WATER USES
The Kerr-McGee uranium mill draws water directly from the San Juan
River for use in its process and as cooling water. This water is then
treated by coagulation and settling.
Although Shiprock has considerable potential as a center for oil,
gas, and mineral development, tourist activity, and Indian affairs, the
greatest single item retarding its growth has been the lack of a satis-
factory potable water supply. The town of Shiprock uses the San Juan
River as its source of municipal water supply. River water is obtained
principally from infiltration galleries located in the river bed approxi-
mately one-half mile below and on the opposite side of the river from the
uranium mill. This supply is supplemented by surface water drawn directly
from the river and, during the summer, by water from a nearby irrigation
canal diverted from the San Juan River nine miles above the town. The
percentages of surface and infiltration gallery water being used at the
time of the November 1960 survey are unknown. The Shiprock water treatment
plant, constructed and operated by the U. S. Bureau of Indian Affairs,
provides for filtration and chlorination of the raw supply. This system
is relied upon to supply an average demand of 0.45 MGD for approximately
2800 persons in the Shiprock area.
The Bureau of Mines Helium Plant also obtains water for domestic
and industrial use through infiltration galleries in the river bed located
approximately 100 yards below the Shiprock intake but on the same side of
the river as the uranium mill with its attendant waste discharges. During
the survey, water was being obtained from two of three galleries, the
furthest upstream being closed. This supply is filtered, softened by
zeolite units, and chlorinated. Average use, including water served to
56 families, is estimated at 60,000 gpd, with a maximum of 160,000 gpd.
The locations of infiltration galleries for both of the above
supplies are shown in Figure 2 and specific information on construction
and size is given in Appendix B.
The only substantial and fixed demand of San Juan River water below
Shiprock for domestic use occurs at Mexican Hat, Utah, 140 miles downstream.
There the river is utilized for water supply to a community of approxi-
mately 400 people. An average of 1.34 MGD of river water is utilized by
the Texas-Zinc Mineral Corporation uranium mill at Mexican Hat, from which
is provided full domestic water services to the community. The domestic
supply receives complete treatment by flocculation, settling filtration,
ion-exchange and chlorination.
Small amounts of water are withdrawn from the river for domestic
purposes at scattered points downstream from Shiprock by Indians, but the
quantity of use and number of persons using river water directly is quite
variable and difficult to determine.
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Httiun Ptoif
Stvege
Loflow
Infiltration
Gallenei
Shipreck
Pumping Stotm
Town Of
S h i or OC k
Htlium Ron*
Wclir Inlok*
Buraeu of
Hlllum Activity
Plea t
&*ck»i|«
Pl«»
T «<(>¦««
EmiKM
Kllf Mt«M
Willi Uiakf
Figure 2
KERR-McGEE
Uranium Mill and Vicinity
Colorado River Basin Project
November, I960
(J)- Sampling Points
scale
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- 3 -
WASTE DISPOSAL
All process wastes at the Kerr-McGee uranium mill at Shiprock are
ponded. A layout of the plant site area is given in detail by Figure 2.
The spent ore slurry is pumped to a tailings pond located between the mill
and the river, herein referred to as new tailings area. Waste liquor, or
raffinate, from the solvent extraction circuit and the yellow cake filtrate
is pumped to ponds on the south side of the mill. The portions of the
ponded liquids which do not evaporate, normally percolate into a 10 to 20
foot thick terrace gravel deposit which is underlain by Mancos Shale. These
liquids then flow laterally over the shale to the edge of the bluff, where
the shale outcrops from 10 to 20 feet above the narrow flood plain of the
river. The major portion of the seepage appears in various gullies and
washes where the alluvium has been eroded from the bluff.
Cooling water from the uranium mill fusion furnace and intermittent
overflow from the process water storage tank are discharged to separate
ditches which drain directly to the large wash as shown in Figure 2 and
thence to the river. This wash is herein referred to as the mill drain.
Domestic sewage from the uranium mill is treated in a septic tank and the
overflow is discharged to a tile drain field. However, during the survey
it was found that the septic tank effluent was entering the ditch carrying
the overflow process water. This was apparently due to a brokenpipe
leading to the tile drain field.
Waste disposal facilities at the Helium Plant consist of a septic
tank followed by a waste stabilization pond. Sanitary sewage from the
town of Shiprftck is received by two separate collection systems each having
a waste stabilization pond for treatment of wastes. A small complex of
homes, house trailers and a service station are also located about 0.3 miles
south of the town of Shiprock at the intersection of Highways U.S. 666 and
New Mexico 504. The latter development utilizes individual septic tanks
for the disposal of domestic sewage and that from the gas station.
CONDUCT OF THE SURVEY
Samples were collected from five river locations; the untreated
water supplies for the town of Shiprock and the Helium Plant; six seeps
along the south bank of the river in the immediate vicinity of the uranium
mill; the mill drain, and spent plant cooling water and process water over-
flow; and the drainage channel below the bluff and uranium mill which inter-
cepts most of the surface discharge from the adjacent land area. The
sampling period consisted essentially of two 4-day compositing cycles,
November 15-18 and November 19-22, 1960, with variations in the sampling
dates for each station as noted below.
Descriptions of Sampling Stations
Figures 1 and 2 show the location of sampling stations. The river
bottom in the sampled reach of the San Juan River consists of fine, shifting
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- 4 -
sand and scattered gravel bars. Descriptions of the stations are as follows:
Station Sampling
Code Description Dates
1 San Juan River 9 miles above Shiprock. Water samples Nov.15-18,
were obtained from the irrigation diversion structure. 19-22
2A San Juan River at Shiprock. A composite sample was Nov.19-22
taken at three locations across the main channel from
U.S. Highway 666 bridge.
2B Drainage channel at Shiprock. Samples taken from high- Nov.19-22
way 666 bridge. Flow in this channel at south bank of
river consisted entirely of seepage and mill drain water.
3 Untreated water - Town of Shiprock. Samples were ob- Nov.15-18
tained from the raw water tap in the pumphouse near
the river.
4 Untreated water - Helium Plant. Samples were obtained Nov.15-18
upon discharge to the chlorination tank within the 19-22
plant grounds.
5 San Juan River 3 miles below Shiprock. Samples were Nov.16-18
taken at quarter-points from the cable at the U.S.G.S. 19-22
gaging station.
6 San Juan River 6 miles below Shiprock. Samples were Nov.15-18
obtained by hand at quarter points across the stream 19-22
by wading.
7 San Juan River at Mexican Hat, Utah, 140 river miles be- Nov.15-18
low Shiprock. Samples were taken by wading at midstream 19-22
above the mouth of Gypsum Creek, thus avoiding any possible
contamination from discharges from the Texas-Zinc uranium
mill.
8 Seepage 100 yards downstream from Helium Plant water in- Nov.16-18
take. Samples taken at mouth of gully. 19-21, 23
9 Seepage 300 yards upstream from highway bridge. Samples Nov.16-18
taken below mouth of gully. A large amount of trash had
been thrown into this gully.
10 Mill drain. Samples taken approximately 100 yards above Nov.16-18
mouth of wash, 500 yards upstream from bridge. There was 19-21, 23
no natural flow in this wash during the Nov. 1960 survey.
The August 1960 spill followed this route to river.
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- 5 -
Station Sampling
Code Description Dates
IOC Mill cooling water ditch. Sediment sample taken near Nov. 18
raffinate ponds.
10S Mill process water overflow ditch. Sediment sample Nov. 18
taken 5 yards below end of discharge pipe on mill grounds.
11 Seepage 800 yards upstream from highway bridge. Samples Nov.16-18
taken near mouth of gully just inside mill grounds. 19-21, 23
12 Seepage 1500 yards above highway bridge. Samples taken Nov.16-18
in gully adjacent to new tailings pond. 19-21, 23
13 Seepage 200 yards above uranium mill water intake. Sam- Nov.16-18
pies taken at mouth of wash. (The next upstream wash, 19-21, 23
Dead Man's Wash, although draining a much larger area,
was dry.)
14 Seepage 350 yards below uranium mill water intake. Nov.19-21,23
Samples taken at mouth of gully.
Samples of bottom organisms were obtained from the river at points
2 miles above the mill and 0.5, 3, 6 and 10 miles below the mill. The 3-
and 6-mile biological sampling points correspond to Stations 5 and 6, re-
spectively, given above.
Sampling Procedures
All liquid samples were grab samples taken once daily at all stations
and composited for each sampling cycle. The composites amounted to one gallon
for uranium and radium-226 analyses, one gallon for chemical analyses, and
one quart for gross radioactivity determinations. In addition, one-gallon
sample was composited over the total survey period from each of the seeps and
the mill drain for fish toxicity studies. Liquid samples were collected in
polyethylene bottles.
At each river station, sediment samples were collected once during each
sampling cycle and then composited over the two cycles. Where possible, sedi-
ment samples were obtained at quarter-points across the stream with an Ekman
dredge and elsewhere by hand at accessible points. At each seep and mill
drain station, mud samples were taken once during the survey. Sediment and
mud samples were collected in one-pint glass jars.
Discharge Measurements
Discharge measurements were made once during the survey at each of the
seep and mill drain stations using a V-notch weir at Station 8, 10, and 11
and a volumetric method at Stations 12, 13, and 14. The flow at Station 9
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was estimated visually. No flow measurements were undertaken at Station 2B
and of the two raw water supplies. There appeared to be little or no
variation in discharge from the seeps during the survey. The mill drain
discharge was more variable and appeared to be slightly higher at the time
of measurement than at other times during the survey. These flow determina-
tions are presented in Table I. San Juan River flows are given in the next
section of this report.
TABLE I
Discharge Measurements of Seeps in Shiprock Area
November 1960
Flow (gpm)
20
1
130
20
0.5
1.5
4.5
Station
8
9
10
11
12
13
14
HYDROLOGY
The average flow of the San Juan River at the U. S. Geological
Survey gaging station 3 miles below Shiprock for the survey period was
625 c.f.s. This is less than the November mean of 843 c.f.s. for the
period of record from 1928 to 1959 but considerably higher than the
1960 summer low of 65 c.f.s. on August 21. The lowest recorded daily flows
at Shiprock were 8 c.f.s. in August, 1939 and 12 c.f.s. in July, 1959 (2)
(3). Flow frequency studies indicate that a mean daily discharge of 9
c.f.s. or less would occur at Shiprock once approximately every 20 years (4).
Mean daily discharges of the San Juan River at Shiprock and Mexican
Hat for the survey period and average values derived from the period of
record, as reported by the U. S. Geological Survey are given in Table II.
Hydrographs for calendar years 1959 and 1960 are shown in Figure 3 for the
Shiprock location to illustrate recently-occurring annual flow patterns in
the river. The 1960 flow information shown herein is taken from USGS pro-
visional records whereas the 1959 data is obtained from published records.
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6,000.
J
«4
u
c
5
o
_i
4,000
Ul
2,000
V/
JAN
FEB MAR APR
MAY JUNE JULY
! Figure 3
Hydrographs of the
San Juan River at
Shiprock, New Mexico
Colorado River Basin Project
i
1959 1
-1960-
I
is
Ir t
survey
period
OCT NOV DEC
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- 7 -
TABLE II
Mean Daily Discharges of the Sari Juan River
At Shiprock, New Mexico and Mexican Hat, Utah (cfs)
Date Shiprock, N. M. Mexican Hat, Utah
November 15, 1960
16
17
18
19
20
21
22
23
Mean period of survey
November 1960 mean
November mean, period of record
Annual mean, period of record
637
670
621
651
645
620
654
613
630
620
610
595
581
583
621
607
629
566
625
614
632
665
843 (1928-59)
1,014
450
2,790
PRESENTATION AND DISCUSSION OF ANALYTICAL RESULTS
Radiological
The gross radioactivity assays of all water and sediment samples
were performed at the Taft Sanitary Engineering Center in Cincinnati, Ohio.
A portion of the radium-226 determinations and all of the uranium analyses
were performed by Colorado River Basin Project Laboratory personnel tem-
porarily located at the Occupational Health Field Station in Salt Lake City.
The remainder of the radium-226 determinations were performed by a private
laboratory.
Results of radiological analyses of seep and mill drain liquid and
mud samples are presented in Table III. Radioactivity levels of river water
and river sediment and raw water supplies are presented in Table IV.
Seep and Drain Liquids.
Seepage liquids exhibited a wide range of dissolved gross radio-
activity, average values ranging from 17 to 860 micromicrocuries per liter
alpha activity and from 150 to 1600 n|ic/l beta activity. The highest acti-
vities were found in seepage in the immediate vicinity of the tailings
ponds (Stations 12 and 14), while seeps most distant (Stations 8 and 13)
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TABLE III
a/
RADIOACTIVITY OF SEEP AND DRAIN SAMPLES -
b /
Liquids-
Mud
Sample No. Location
Gross
Alpha
uuc/1
Gross
Beta
uuc/1
Ra-22b
uuc/1
Uranium
us/1
Gross
Alpha
uuc/g
Gross
Beta
uuc/g
Ra-ZZb
uuc/g
2B7
Drainage channel at bridge
90
220
1.8
340
16
47
8
Seep: 100 yds below helium
plant intake
21
13
100
200
0.5
0.6
16
46
2.2
gd/
Seep: 300 yds above bridge
31
0.2
56
2.6
10
Mill drain
200
140
190
180
2.5
2.9
860
560
650
600
39
10-C
Cooling water ditch
2200
2600
120
10-S
Process water overflow ditch
440
670
120
11
Seep: 800 yds above bridge
94
120
400
420
4.9
5.0
700
530
470
770
115
12
Seep: 1200 yds above bridge
770
760
1400
1800
2.1
1.4
3800
3900
150
200
14
13
Seep: 200 yeds above mill
water intake
19
70
260
0.2
0.2
7.2
1.6
Seep: 350 yds below mill
860
1600
2.0
4800
30
57
4.2
water intake
a/ First and second values correspond to sampling cycles I and II, respectively, for which sampling
c}ates are given in Page 4 of this report,
b/ Dissolved fraction only,
c/ Cycle II only
d/ Cycle I only
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TABLE IV
a /
RADIOACTIVITY OF RIVER AND RAW WATER SAMPLES~
Water
Sediment
Station
Number
Location
Gross
Alpha
uuc/1
Gross
Beta
uuc/I
Ra-226
uuc/I
Uranium
Ug/1
Gross Gross Ra-226
Alpha Beta
uuc/g uuc/g uuc/g
SAN JUAN RIVER
1 9 mi. above mill
2A Shiprock bridge
5 3 mi. below mill at USGS gage
6 6 mi. below mill
7 Mexican Hat
RAW WATER SUPPLIES
3 Town of Shiprock
Helium Plant
3.1
5.0
5. 1
3.3
7.3
4.5
7.9
6.4
3.4
8.6
8.8
6.9
2.6
7.8
8.3
7.4
15
15
6.0
6.0
35
15
28
8.3
17
13
0.2
<1.
0.3
0.2
0.2
<1
<1
0.2
0.2
0. 1
0.1
0.0
0.1
12
20
20
13
21
16
20
16
13
44
34
28
25
9.1
6.5
5.3
4.9
4.8
36
58
25
25
37
1.5
1.0
0.9
1.6
1.5
a/ First and second values correspond to sampling cycles I and II, respectively, for which sampling
dates are given in Page 4 of this report,
b/ Dissolved fraction only,
c/ Cycle II only.
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showed the least activity. A number of factors could be responsible for
this variation, including the length of subsurface travel, the precipitation
of solids while in transit, ion exchange in the alluvium, and the source of
liquid involved.
Average concentrations of Ra-226, an alpha emitter, ranged from 0.2
to 5.0 (j.p.c/1 for individual stations and accounted for from 0.1 to 8 percent
of the respective gross alpha activities. Uranium contributed most of the
remaining gross alpha. The Ra-226 concentrations of all samples were unu-
sually low, considering the source of wastes and the high gross alpha
activity and uranium content. Average dissolved uranium concentrations
ranged from 340 to 4800 ng/1.
Since the flow in the mill drain of 130 gpm was more than twice the
total of all seepage discharged, the latter being equal to 50 gpm, the
quality of mill drain effluent was important. Its characteristics vary
considerably, since it is directly affected by short-term variations in
plant processing. Gross alpha and beta activities and uranium concentra-
tions for the mill drain water were considerably less than those found in
seepage nearest the tailings ponds, while gross alpha and Ra-226 activities
of the drain water were higher than those found in seeps more distant from
the tailings. Uncertainty as to the source of radioactivity was introduced
by the presence in this channel of residue from the August 1960 spill. Some
of the dissolved radioactivity values found in the mill drain water may have
been leached from these deposits.
The U. S. Atomic Energy Commission Standards for Protection against
Radiation (5) require that effluents to unrestricted areas from private
entities licensed to possess radioactive materials contain a maximum of
10 n^c/l Ra-226 plus one-half of the equilibrium amounts of its daughter
products. None of the sampled seepage nor the mill drain exceeded this
limit during the November 1960 survey.
The total Ra-226 discharged to the river in all discharges sampled
was 2.6 per day. This amount could not have produced detectable in-
creases in Ra-226 concentrations in the San Juan River at the time of the
survey, considering the dilution provided by a discharge of more than 600
c.f.s. It was previously estimated that a low flow of 9 c.f.s. or less
would occur, on the average, once every 20 years. For this discharge the
Ra-226 contribution of all the seeps and the mill drain to San Juan River
water would be 0.1 np.c/1, still virtually undetectable. The latter findings
however do not condone the routine discharge of greater amounts of radio-
active material or an accidental release such as occurred on August 22-23,
1960.
Seep and Drain Muds.
The mud samples from the seeps in the immediate vicinity of the
tailings, especially Stations 11 and 12, showed considerable gross alpha
and beta and Ra-226 activity. The liquid samples from these two seeps in
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- 9 =
addition had high dissolved gross radioactivity. The mill drain (Station 10)
mud samples also indicated deposits of solids having considerable alpha and
beta radioactivity. In fact, the 39 n^ic/g Ra-226 in the mill drain mud was
higher than mud Ra-226 concentrations found in this drain at approximately the
same location following the August spill (1).
The highest gross radioactivity and radium counts were obtained from
mud collected from the channel carrying the cooling water (Station 10C) as
it passed near the raffinate holding ponds. The holding ponds emptied by
the August spill remained unfilled during the November survey. From the
Ra-226 concentration of 120 |i|ic/g in mud from the cooling water channel
observed during this survey and from samples collected following the August
1960 spill (1), it was observed that the sediment activity of the cooling
water channel was comparable to observed levels of radioactivity in sludge
samples collected in August 1960 from the nearby holding ponds. Seepage
from these lagoons may contaminate the cooling water channel, which is then
scoured and the sediment transported throughout the mill drain.
Mud obtained from the channel carrying the process water overflow
(Station 10S) to the mill drain also showed high radioactivity. Its Ra-226
concentration of 120 wac/g was equal to that of the cooling water channel mud.
A possible explanation of this level of radioactivity in this channel is
contamination by dust from ore trucks and nearby ore stockpiles.
River Water
Samples at stream locations above all sources of radioactive conta-
mination yield important data on natural background radioactivity levels.
Such samples (4) (6) (7) (8) contain gross alpha activity up to 10 |i(ic/l, gross
beta up to 50 wic/1 and soluble Ra-226 activity generally less than 0.3 pjic/1.
Although industrial sources of radioactive pollution exist upstream of Ship-
rock, these are of no consequence at Shiprock because of substantial dilution
and the minimal amounts initially present. Accordingly, the levels of radio-
activity in river water at Station 1 above Shiprock were found to be in the
background range. (See Table IV)
All downstream river water samples also showed gross radioactivity,
Ra-226 and uranium concentrations approximating background conditions.
There were no significant increases over upstream levels, and none would
have been expected, considering the small total amounts of radioactivity
discharged from the Shiprock uranium mill and the available dilution.
Average gross alpha and beta activities over the entire stretch of
river under study varied from 4.1 to 6.2 |4ic/l and 6.0 to 25 n(ic/l, res-
pectively. Dissolved Ra-226 concentrations were equal to or less than 0.3
H(ic/1 for all finite results; three results simply indicated levels equal
to or less than 1.0 ^ijic/l. Dissolved uranium values for river water again
did not vary from upstream to downstream locations and ranged from 12 to
20 |ig/l throughout the study area.
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Raw Water Supplies
Radioactivity of raw water from the Shiprock pumping plant and the
Helium Plant was comparable to river water samples. Uranium concentrations
were slightly higher, while Ra-226 was low (0.1 nM-c/l or less). Gross alpha
activities in the raw water supplies were not significantly above that of
river water.
The National Committee on Radiation Protection (9) has established
maximum permissible concentrations (MPC) of radionuclides in water for
continuous occupational exposure. In addition, the International Com-
mittee on Radiological Protection (10) recommends a conversion factor of
1/30 for members of the population at large. The resulting MPC for Ra-226,
a bone-seeker, is 3.3 (i(ic/l and for natural uranium is 6700 np.c/1, or 9500
The 1961 Public Health Service Drinking Water Standards (11) include
radioactivity limits for the first time. Radium-226 concentrations which
exceed 3.0 nnc/1, on the average, for a period of one year, shall consti-
tute grounds for rejection of the supply. Concentrations of Ra-226 and
uranium in the raw water samples for Shiprock and the Helium Plant were
well within the Maximum Permissible Concentrations given above. Also gross
radioactivity levels in the raw waters were in the range of background as
normally found for river waters.
River Sediments
Information concerning natural background levels of radioactivity
in stream sediments are also available. Results of gross alpha, gross
beta, and Ra-226 analyses of several samples collected during this Project's
first Basinwide sediment survey (12) are given in Table V. As can be seen
from Table IV, all San Juan River sediments collected in the Shiprock area
in November, 1960 from below the mill, fall within these ranges.
TABLE V
Background Levels of Radioactivity
In Stream Sediments (12)
Location
Colorado River at Silt, Colorado
Yampa River at Juniper Springs, Colo.
Green River near Dutch John, Utah
San Juan River above Farmington, N.M.
Animas River above Durango, Colorado
San Miguel River above Naturita, Colo.
Gunnison River above Gunnison, Colo.
Tomichi Creek above Gunnison, Colo.
Gross a Gross £ Radium
uuc/g uuc/g uuc/g
6. 5 78 1.7
4.0 50 <1.0
8.6 45 <1.0
5.3 21 0.9
11.0 29 1.3
9.5 38 1.0
9.0 52 1.6
11.0 47 1.2
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- 11 -
Chemical
Results of chemical analyses performed on seep and drain samples
are presented in Table VI, and chemical analyses on river and raw water
supply samples are presented in Table VII. All chemical determinations
were performed in accordance with Standard Methods (13).
Seep and Drain Effluents
In considering the various seeps that were sampled, those nearest
the tailings ponds contained the highest chemical concentrations. Total
dissolved solids, calcium, magnesium, and sodium contents were not re-
ported. However, estimates of total dissolved solid levels based on re-
ported anion concentrations ranged from 9,000 mg/1 for Station 8 to 14,000
mg/1 for Station 12. The seep liquors were also very hard, containing a
large portion of non-carbonate hardness. The latter is shown by the dif-
ference between total hardness and alkalinity. High levels of sulfates
undoubtedly contributed most of the non-carbonate hardness. Concentrations
of chemical constituents in the seep samples varied considerably: hardness
from 3,400 to 10,400 mg/1, sulfates from 3800 to 3900 mg/1, alkalinity from
256 to 1660 mg/1, chlorides from 99 to 440 mg/1, and nitrates from 111 to
1640 mg/1 (as NO^).
The high sulfate content of the seeps may have been due to sulfuric
acid in the slurry (pH about 2.0) pumped to the tailings pond, or to the
leaching of natural sulfates from the ground. The very high nitrate and
relatively high chloride concentrations of the seeps were apparently also
due to leaching of these salts from the alluvium and/or waste ponds.
Ammonia was used in the process and contained in the wastes sent to the
barren liquor ponds, where it may be converted to the nitrates form.
The mill drain samples were nearly equal to or somewhat lower than
seep samples in all chemical concentrations except vanadium which was
higher. This drain was the most important source of chemical pollution
because of its greater waste volume. Much of the dissolved solids content
of this discharge (estimated t.d.s. 6,000 mg/1) was likely being leached
from solids deposited in this channel during the August spill (as was pre-
viously suggested for radioactive materials).
The drainage channel at the bridge, Station 2B, was high in sulfates
(3900 mg/1), nitrates (806 mg/1), and chlorides (330 mg/1) and was a poten-
tial source of chemical pollution to the infiltration galleries immediately
downstream.
The mineral contribution to the river of all measured seepage and
the mill drain has been determined for various constituents, using average
concentrations obtained over the two sampling cycles. For a time-of-survey
river discharge of 625 c.f.s., the total seep and drain discharge to the
river would increase alkalinity by 0.2 mg/1, sulfates and hardness by 2 mg/1,
-------
TABLE VI .
CHEMICAL QUALITY OF SEEP AND DRAIN SAMPLES^
(All Values Reported in mg/liter except pH)
b/ c/ b,
Station 2B~ 8 ST 10 11 12 U 14~
Analyses
PH
7.8
7.5
6.7
7.6
7.4
7.5
7.0
7.9
7.8
7.6
7.5
7.5
7.5
Total Alka-
256
365
235
1320
1570
905
linity
440
320
180
1210
1660
1000
1250
(as CaCO^)
Fluoride
0.82
0.90
0.57
0.86
1.2
0.82
0.65
0.84
0.57
0.84
1.1
0.74
0.62
Selenium
_ _ _
.009
.003
<.001
.004
.008
.009
_ _ _
<.001
.001
.002
.005
.007
.002
.002
Iron
.04
.09
.09
<. 04
1.6
<.04
.28
.05
.53
.04
<.04
.05
<04
Manganese
.04
<.04
.17
<.04
4.9
.04
.31
<.04
.26
<. 04
4.9
<.04
<.04
Sulfate
3900
3900
2800
3900
3900
3900
3900
3900
2000
3800
3800
3800
3900
Total
3400
3870
2170
6800
10800
5850
Hardness
3400
3400
1600
6700
10300
5660
5400
(asCaCOg)
Chloride
106
280
142
430
440
390
330
99
215
430
428
413
174
Copper
<.01
<.01
<.01
<.01
.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
Vanadium
<.003
<.003
.300
<.003
.007
<.003
.111
<.003
.442
<.003
.007
<.003
.033
Nitrate
487
Ill
266
1640
1462
1484
(as N03)
80$
478
257
1462
1218
1440
310
Phosphate
<.5
<.1
<.1
<.1
<.5
<.1
(total)
<.1
<. 1
<1
<.1
<.5
<.1
<. 5
Lead
.018
.022
.008
.010
.015
.012
.025
.005
.005
.005
<.005
<.005
.010
Arsenic
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
a/ First and second values correspond to sampling Cycles I and II, respectively,
for which sampling dates are given in Page 4 of this report,
b/ Cycle II only.
c/ Cycle I only.
-------
TABLE VII CHEMICAL QUALITY OF RIVER AND RAW WATER SAMPLES^
Shiprock, New Mexico Area, November I960
(All Values Reported in mg/liter, except pH)
Station 1 2A~ 3 4 5 6 7
Analyses
PH
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.4
7.5
7.5
7.6
7.8
7.5
Total
113
...
177
111
152
152
174
Alkalinity
164
156
180
200
162
170
174
Fluoride
0.45
0.53
0.37
0.49
0.45
0.43
0.49
0.53
0.57
0.37
0.45
0.51
0.53
Selenium
.009
.006
.006
.008
.008
<.001
<.001
<.001
.002
.003
.005
.003
.006
Iron
.57
.41
.07
.66
.90
3.9
.56
.72
.08
. 12
.46
.75
1.8
Manganese
<.04
.30
<.04
<.04
.05
.18
.04
<.04
<.04
.05
<.04
.05
. 10
Sulfate
320
...
790
510
400
430
540
295
345
530
480
360
390
510
Total
320
680
430
450
450
450
Hardness
360
360
570
470
380
380
450
Chloride
16
66
26
18
18
22
16
19
46
27
20
22
20
Copper
<.01
.01
<.01
.01
.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
Vanadium
.010
-
<.003 '
<003
<.003
<.003
.026
.010
.010
.033
<.003
.006
.004
.010
Nitrate
.35
.71
.31
. 13
.04
2.2
(as N03)
.49
1.9
13.3
13.4
2.0
1.6
2.6
Phosphate
<5
<.1
<.5
<.1
<.1
<.1
(Total)
<.1
<. 1
<.1
<.1
<. 1
<.1
<.1
Lead
<.005
...
.005
.010
.045
<.005
<.005
.008
.005
.008
<.005
.008
.010
.045
Arsenic
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<.01
<01
<.01
<.01
<.01
a/ First and second values correspond to sampling Cycles I and II,
respectively,
b/ Cycle II only.
-------
- 12 -
and chlorides and nitrates by 0.1 mg/1. These increases are usually
undetectable, considering concentrations generally found in the San
Juan River. Observed chemical concentrations in the river water are
discussed below.
However, for a daily river discharge of 9 c.f.s., the estimated
20-year low flow, dilution would not be adequate (as almost expected)
to prevent serious chemical pollution in the San Juan River. Sulfates
and hardness would each be increased by 110 mg/1, alkalinity 15 mg/1,
chlorides 10 mg/1, nitrates as NO3 22 mg/1, and vanadium by 0.01 to
0.02 mg/1. Pollution introduced by other chemicals for which results
are reported in Table VI, that is fluorides, iron, manganese, copper,
phosphates, lead, arsenic and selenium, would be negligible in all
cases.
River Waters
As noted above, no observable increases in chemical concen-
trations would have been expected in the river water at the time of
the survey due to the direct waste discharges from the uranium mill
area. However, average sulfate levels at downstream locations, as
shown by Table VII, did increase in the order of 35 percent from 300
to 400 mg/1 and likewise hardness increased 20 percent from 340 to
415 mg/1. Values at Stations 5 and 6 were compared with Station 1 for
this purpose. The river water was quite high in sulfates and hardness
even upstream of Shiprock, undoubtedly due in large part to natural
sources above this point. Nitrates also were higher downstream,
increasing from an average of 0.4 mg/1 at Station 1 above Shiprock to
2.4 mg/1 at Station 7. Iron content was relatively high and showed a
large increase from Station 5 to Station 7, both stations located below
Shiprock, with maximum levels of 3.9 and 1.8 mg/1 at Station 7. As the
seep samples were especially high in hardness, sulfates, and nitrates,
the possibility of considerable groundwater seepage to the river, both
from the Shiprock uranium milling activity and from natural sources,
is indicated.
Raw Water Supplies
Some chemical constituents in the raw water supplies are reported
to have been present in concentrations higher than the recommended limits
presented in the Public Health Service Drinking Water Standards (11).
These are discussed individually.
Sulfates averaged 660 mg/1 in the Shiprock raw water, nearly twice
the concentration in the main channel of the river at the infiltration
galleries (Station 2A). In the Helium Plant raw water, sulfates averaged
495 mg/1. The limit recommended in the Drinking Water Standards is 250
mg/1. The infiltration galleries for the Shiprock water supply have
reportedly produced a sulfate concentration as high as 2933 mg/1 (14).
As mentioned previously, river samples both above and below Shiprock also
contained sulfate concentrations greater than 250 mg/1.
-------
- 13 -
The Drinking Water Standards recommend a nitrate limit of 45 mg/1
as NO3, since higher concentrations if used are associated with greater
incidence of methemoglobonemia in infants. Although this limit was not
exceeded during the survey, uncertainty exists in the long-term nitrate
levels in the water supply of both water plants.
Samples collected of the Shiprock water supply at various points in
the distribution system by the New Mexico Department of Public Health over
the period January 1957 to January 1958 indicated levels of 124 to 195 mg/1
nitrates (as NO3). Results from two samples collected from the Helium Plant
water system in 1956 and 195 7 showed nitrate concentrations of 0,4 and 8.9
mg/1 as NO3. Levels of nitrate in three San Juan River water samples col-
lected in the Shiprock area from April, 1957 to January, 1958, by the New
Mexico Department of Public Health, ranged from 1.8 to 4.4 mg/l as N03(15).
Some variation of nitrate level in the Shiprock water supply may be
explained by an alternation of source from surface water to gallery water
and vice versa. All of the Helium Plant supply is however obtained from
infiltration galleries. Personnel at the Helium Plant in November of 1960
related that nitrate concentrations increase greatly when river water is
pumped from the collector furthest upstream. Because of the very high nitrate
levels determined for the Shiprock water supply by the State of New Mexico
as given above, and uncertainty of the nitrate content of the Helium plant
supply, further study of factors contributing to this effect is definitely
indicated.
During Cycle I, a value of 0.41 mg/1 iron was obtained for the Ship-
rock raw water, which is higher than the Public Health Service recommended
limit of 0.3 mg/1 for this same material. This limit is based on the
tendency of iron to stain laundry and porcelain. The two samples collected
of Helium Plant raw water and the second sample taken of Shiprock inflow
contained lesser iron concentration, approximating 0.1 mg/1. It is noted
that all river samples were shown to have an iron content greater than the
0.41 mg/1 found for the Shiprock water supply sample of Cycle I. The
recommended limit for manganese is 0.05 mg/1. The Shiprock raw water sample
from Cycle I showed a Mn concentration of 0.3 mg/1, well above the desired
level. The manganese content of all other raw water and river samples were
equal to or less than 0.05 mg/1 excepting the waters at the furthest downstream
location of Station 7 which contained an average of 0.14 mg/1 Mn.
Although there are no drinking water standards for hardness, water
containing an excess of 250 mg/1 is usually considered undesirable for
domestic and industrial use in most sections of the country, without prior
softening. Total hardness of the Shiprock raw water averaged 625 mg/1, and
at the Helium Plant, 450 mg/1. Hardness levels in river water were also
above 250 mg/1 as discussed above.
-------
- 14 -
Chloride concentrations in the untreated water supplies were consider-
ably below the maximum permissable level of 250 mg/1, based on tastes in drink-
ing water. However, it is observed that chloride levels were somewhat higher
in the water obtained from the infiltration galleries than in the river
directly above the galleries.
Raw water determinations other than those already discussed were all
within recommended limits for acceptable drinking water.
Biological
Bio-Assay
Fish toxicity studies were undertaken at the Taft Sanitary Engineer-
ing Center in Cincinnati, Ohio, with the seep and drain sample collected in
the vicinity of the Shiprock uranium mill. Bluegill sunfish one and one-
quarter inches to two inches in length were exposed to various dilutions of
effluent liquors from sampling Stations 8, 9, 10, 11, 12, 13, and 14. The
prepared dilution water had a pH of 7.4 and contained 18 mg/1 alkalinity and
20 mg/1 hardness.
Initially, one fish was tested in one liter of each effluent at 100
percent concentration. Within 30 minutes, the test fish in the seep effluent
from Station 12 was dead. At the same time, two test fish were placed in a
2-liter volumes of 100, 10, and 1 percent concentrations of all effluents
except No. 12. All the test fish observed in the various concentrations of
samples from Stations 8, 9, 10, 11, and 14 were alive at the end of a 96-hour
test. In the various concentrations of the sample collected from Station 13,
all fish were alive after this 96-hour period except one fish in a concentra-
tion of one percent effluent.
Further information was desired on the characteristics of the drainage
liquor from Station 12. Therefore, two fish were placed in 2-liter volumes at
waste concentrations of 56, 32, and 1 percent. Additionally two fish were
placed in 2-liter volumes, in duplicate, at 18, 10, and 5.6 percent waste con-
centrations. The results of bio-assay tests with this seep effluent are
shown in Table VIII.
TABLE VIII
Bioassay Tests on the Kerr-McGee Seep Sample No. 12
No. of Volume Test % Survival
Fish Liters Concentration 24 hrs. 48 hrs. 12 hrs. 96 hrs.
1
1
100%
0
-
-
-
2
2
56
0
-
-
-
2
2
32
0
-
-
-
2
2
18 1/
0
-
-
-
2
2
10 1/
100
0
-
-
2
2
5.6 1/
100
100
100
100
2
2
1.0
100
100
100
100
1/ In duplicate
-------
- 15 -
Since only two fish were used in each test, the results obtained
are indicative only of a general range of toxicity, and should be inter-
preted in this light. The data presented in Table VIII indicate that the
96-hour median tolerance limit (TLm), or the concentration of waste of
Station 12 that will kill half of the test fish in a 96-hour period, is in
the range of 5-10 percent. To prevent damage to fish life in the receiving
stream the necessary dilution water may be calculated by the formula:
Dilution Water = 100 - TLm x waste flow x application factor
TLtn
The application factor will vary according to the characteristics of
the waste and receiving stream. Generally, this factor is not less than 3
and may be 10 or more. The purpose is to provide sufficient water in excess
of the TT, concentration to dilute the wastes to a harmless concentration.
Using the flow of 0.5 gpm given previously for Station 12 and the
above ranges of TL^ and application factors the required dilution of &an
Juan River water to completely mitigate fish toxicity for conditions ex-
perienced during the survey ranged from 0.03 cfs to 0.21 cfs. There should
be no toxicity problem to fish and wildlife attributable to waste discharges
from the Kerr-McGee uranium mill under normal operating procedures, since
the flow of the San Juan River at Shiprock is always much greater than the
minimum required.
Biological Sampling Collection of bottom organisms was undertaken at
one station above the Shiprock uranium mill and at four downstream locations.
Detailed examination of stream biota was not made. However, some informa-
tion of interest was obtained. Bottom fauna collected from one square yard
at selected river locations is shown in Figure 4.
The volume of organisms per square yard was about the same at the
station upstream from the mill and at the stations 6 and 10 miles downstream.
The collection was composed mainly of caddis, stone, dragon and may flies.
At the stations near the Helium Plant water intake (0.5 mile below the mill)
and near the USGS gage (3 miles below the mill), the bottom organisms were
far less numerous but consisted of a fairly good variety. It is likely that
this sparcity of organisms was the residual result of the relatively large
amount of toxic wastes released during the accidental uranium mill spill of
August 22-23, 1960 rather than an effect of continuous mill discharges under
normal operation. The bottom fauna at the stations 6 and 10 miles below
the mill apparently were not affected by adverse conditions during the
preceeding few months.
Since the flow in the river in August I960, at the time of the spill,
was very low, there is a likelihood that much of the wastes released ac-
cidentally at that time traveled in a somewhat confined channel, and
marginal areas received little of this effluent. Effort was made, during
this survey, to sample what appeared to be the main channel in riffles, and
duplicate the area covered by the flowing stream in August of 1960.
-------
- 16 -
There is considerable value in future sampling of biological life in the San
Juan River in the vicinity of Shiprock during a period of very,low flow.
Although such activity will have little value in estimating the past effects
of the spillage of mill wastes in August 1960, the effect of continous dis-
charges from the uranium mill area may be evaluated more fully.
Figure 4
Relative Volumes of Bottom Fauna Collected from One Square Yard
San Juan River at Shiprock, New Mexico, November 1960
2 miles
Above Mill
0.5 mile
Below Mill
f~ | Clear Liquid
3 miles
Below Mill
6 miles
Below Mill
10 miles
Below Mill
Y / A Bottom Fauna
SUMMARY AND CONCLUSIONS
1. An eight-day field survey was undertaken in the Shiprock, New Mexico area
during November 15-23, 1960 to determine the pollutional significance of the
many seeps and drainages to the San Juan River from the general area of the
Shiprock uranium mill. The quality of river water above and below Shiprock and
of the water supplies for the town of Shiprock and the Navajo Helium Plant were
also determined. This survey was a follow-up to determine residual
effects of an accidental spill of toxic wastes released from the Shiprock
uranium mill on August 22-23, 1960. Water quality conditions were evaluated on
the basis of radiological, chemical and biological data collected in the study
area.
2. The proximity of a number of seeps to the Kerr-McGee uranium milling activity,
and the relatively high chemical and radioactivity content of seepage indicate
that the source of this seepage very likely is the tailings and/or barren liquor
ponds at the mill.
-------
- 17 -
Discharge via the mill drain, consisting of cooling water and wasted
process water, is the most important single source of direct mill pollution to
the San Juan River because it comprises the majority of total surface waste
discharge from the mill. The flow in the mill drain is affected by variations
in plant processing but additionally it was found that considerable radiological
contamination was present in the form of deposits probably resulting from the
accidental mill spill of August 1960.
3. The range in average dissolved radioactivity levels of the various seepages
and mill drain effluent were 17 to 860 |i|ic/l alpha activity, 150 to 1600 |ijic/l
beta activity, 340 to 4800 |ig/l uranium and O.Z to 5.0 nnc/1 radium-226.
Radioactivity in muds collected from seeps soemwhat distant from the mill
proper were in the order of 1-3 times background levels. The cooling and
process water ditches (Stations 10C and 10S) leading to the main drain, the
seep as measured by Station 11 and the main drain at Station 10 contained muds
showing very high radioactivity. For these samples, gross alpha activity ranged
from 440 to 2200 |a|ic/g, gross beta from 600 20 2600 p.|j.c/g and radium from 39
to 120 w-ic/g.
Seep and drain liquors were relatively high in levels of various chemical
constituents. The range in average values were hardness, 1900 - 10,600 mg/1;
sulfate 2,400 to 3,900 mg/1; nitrate (asN03) 111 to 1550 mg/1; and total
dissolved solids (estimated), 9,000 to 14,000 mg/1.
4. Radioactive and chemical pollution of the river by direct surface discharge
of the seeps and mill drain were negligible under conditions prevailing at the
time of survey. However, chemical pollution from these sources at times of
very low river flow would be significant.
5. Efforts should be made to seal or other wise maintain high impermeability
of the beds of various storage ponds and lagoons on the mill site. Significant
radioactive contamination of the mill drain by the previous spill of August,
1960 illustrates the long-term contamination caused by such incidents which
must be prevented by correct waste-ponding practices. The source of radio-
active contamination in the cooling water and water overflow ditches need be
more precisely determined and measures taken to correct this situation. The
radiological and chemical quality of the cooling water before it passes hear
the barren waste liquor ponds should be evaluated. The routing of this dis-
charge as found in November, 1960 is highly undesirable and should be alteled.
6. Radioactivity levels in all water and sediment samples collected from
the San Juan River above and below Shiprock were in the range of background.
From chemical analyses of river water samples, it was found that average
sulfate and hardness levels in the San Juan above Shiprock were respectively
300 and 340 mg/1. Substantial increase in both of these chemical values in
the order of 20 to 35 percent was evident in the stretch of river in the near
vicinity of an below Shiprock. Total dissolved solids (although not measured
-------
- 18 -
directly) and nitrate levels in river water in this same area showed similar
increases. It is noted that sulfate, hardness and total dissolved solids
levels in river water above Shiprock were in excess of generally accepted
limits if this water were to be used for domestic supply without suitable
means of treatment. This water quality is undoubtedly affected by natural
influences upstream of Shiprock.
7. Radiological quality of all samples collected of the Shiprock and Helium
Plant raw water supplies was in the range of background.
Sulfate, hardness and chloride levels of the Helium Plant raw water were
somewhat higher than respective concentrations in the river water immediately
upstream of the infiltration galleries. In the case of the Shiprock supply,
the relative increases were even greater. Concentrations of nitrate and
manganese are apparently higher in both raw water supplies than in river
water at the intake locations. The State of New Mexico has collected data
in the past which shows that nitrate levels (expressed as NO^) in the Helium
Plant water system has ranged from 0.4 to 8.9 mg/1, and nitrate in the Ship-
rock water system has ranged from 1^24 to 195 mg/1. Further studies are
necessary to determine levels of iron, manganese and most importantly that of
nitrate, over an extended period of time. These should be related to Drinking
Water Standards.
8. Sizeable increases in sulfates and hardness of San Juan River water in the
vicinity of Shiprock indicate probable ground water contribution of these
constituents. Higher concentrations of certain chemical values in the Ship-
rock and Helium Plant raw water supplies over and above that found in the
river and the high chemical concentrations of the seep liquors further
indicates chemical pollution of ground water particularly from the immediate
area of the uranium mill. Also some correlation exists between the chemical
makeup of seep liquors as compared to the mill drain effluent and to the
makeup of ponded liquors on the mill site. A detailed geological investiga-
tion is recommended to determine the configuration of the ground water table,
the sources and extent of, and the path of travel of ground water contamina-
tion in this area.
9. The bottom fauna population in the San Juan River immediately below Ship-
rock apparently was in a state of recovery from the August 1960 uranium mill
spill. The bottom fauna further downstream (6 miles or greater) apparently
were not affected by these adverse conditions. There is much value in sampl-
ing biological life during period of low flow to evaluate the effect of con-
tinuous waste discharges from the Shiprock uranium mill on this environment.
-------
1
2
3
4
5
6
7
8
9
10
11
12
- 19 -
BIBLIOGRAPHY
Shiprock, New Mexico Uranium Mill Accident of August 22, 1960, U.S. Public
Health Service, Colorado River Basin Water Quality Control Project, Denver,
Colorado (expected publication date, December, 1962).
Compilation of Records of Surface Waters of the United States through
September, 1950, Part 9. Colorado River Basin, Geological Survey Water-
Supply Paper 1313. U.S. Government Printing Office, Washington, (1954).
Surface Water Supply of the United States, 1951 to 1960, inclusive Part 9,
Colorado River Basin. Geological Survey Water-Supply Papers 1213...1713.
U.S. Government Printing Office, Washington, (1953...1961).
Survey of Interstate Pollution of the Animas River, Colorado-New Mexico,
E.C. Tsivoglou, et al, U.S. Public Health Service, R.A. Taft Sanitary
Engineering Center, Cincinnati, Ohio, (May 1959).
Standards for Protection against Radiation, U.S. Atomic Energy Commission,
Federal Register 22, No. 19, January 29, 1957 (amended March 20, 1961).
Report of Survey of Contamination of Surface Waters by Uranium Recovery
Plants, E.C. Tsivoglou, A.F. Bartsch, D.A. Holaday, and D.E. Rushing, U.S.
Public Health Service, R.A. Taft Sanitary Engineering Center, Cincinnati,
Ohio (September, 1955).
Survey of Interstate Pollution of the Animas River, Colorado-New Mexico,
II 1959 Surveys, E.C. Tsivoglou et al, U.S. Public Health Service, R.A.
Taft Sanitary Engineering Center, Cincinnati, Ohio (January, 1960).
Radium Monitoring NetworkData Release No. 1, U.S. Public Health Service,
Colorado River Basin Water Quality Control Project, Denver, Colorado,
(October, 1962).
Maximum Permissible Body Burdens and Maximum Permissible Concentrations of
Radionuclides in Air and Water for Occupational Exposure, Handbook 69,
National Bureau of Standards, Washington, D.C. (July 1959).
Report of the Committee on Permissible Doses for Internal Radiation--1958
Revision, International Committee on Radiological Protection, Pergamon
Press, London, England.
U.S. Public Health Service Drinking Water Standards, Federal Register,
p. 6737, (July 27, 1961); also Journal American Water Works Association,
Vol. 53, No. 8, p. 935-945, (August, 1961).
Unpublished Data to be included in a report Radiological Content of
Colorado River Basin Sediments, U.S. Public Health Service, Colorado River
Basin Water Quality Control Project, Denver, Colorado (expected publication
date, December, 1962).
-------
- 20 -
13. Standard Methods for the Examination of Water and Wastewater, "American
Public Health Association, Inc., Eleventh Edition, New York, N. Y. ,
(March 1961).
14. Potable Water Supply for the Navajo Community of Shiprock, New Mexico -
Feasibility Report, W. F. Turney and Associates, Santa Fe, New Mexico
(July 1960)
15. Information received by letter from the New Mexico Department of Public
HeaLthj Santa Fe, New Mexico (August 21, 1961).
16. Personal visit with Kerr-McGee Uranium Mill personnel (November 1960).
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APPENDIX A
MILL PROCESS AND WASTE DISPOSAL PRACTICES (at the time of the November, 1960
Study)
The Kerr-McGee Oil Industries began operations at its Shiprock, New Mexico
uranium mill in 1954. Nominal capacity of the mill when completed was 400
tons per day of ore. At the time of the November, 1960 Survey, the plant
was processing between 400 and 500 tons of ore per day.
Ore is crushed, sampled, and ground to 18 mesh in a rod mill. Fine ore is
fed to the first of six agitators in series where water and sulfuric acid are
added. At a pH of 1.0 in the agitators the uranium is leached from the ore
pulp.
A sand-slime separation is made on the ore pulp in cyclone separators with
the sands being sent through four spiral classifiers and the slimes through
four thickeners. Fresh water is added to the No. 4 thickener and also to
the No. 4 classifier, and solids are washed as the liquid flows counter-
current to the solids through the four stages. The pregnant overflow liquor
from the No. 1 thickener is sent to the uranium recovery section. Underflow
from the No. 4 thickener and the sands from the No. 4 classifier are mixed
and pumped to the tailings pond. The pH of this slurry is about 2.0.
Uranium in the pregnant liquor is extracted in a 4-stage mixer-settler solvent
extraction circuit. The solvent used consists of 95 percent kerosene and
approximately equi-molar concentrations of tributyl phosphate and di-2-
ethylehexyl phosphoric acid to make up the remaining 5 percent. Raffinate
from the extraction flows to the barren waste ponds. This waste liquor also
has a pH of 2.0 and an approximate flow of 130 gallons per minute. Solvent
losses from the system amount to 1/2 gallon per 1,000 gallons of aqueous
solution. This is reduced to 0.1 gallon of solvent per 1,000 gallons aqueous
by de-entrainment.
The uranium is stripped from the solvent with a 10 percent sodium carbonate
solution and the solvent is recycled. Pregnant carbonate liquor is acidified
to a pH of 3.0 and ammonia is added to precipitate the uranium. This slurry
is filtered and the "yellow cake" product is dried and drummed for shipment.
The filtrate is pumped to the barren waste ponds.
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APPENDIX B-
1
HELIUM PLANT SHIPROCK, NEW MEXICO
INFILTRATION GALLERIES
ro
WEL
40
to sedimentation
basin
PLAN
Scale- l"= 10 0'
bed of river
7
i/V n1
natural gravel bar 1012
3/4 2 gravel
3/4"-H/2"bacKfill"" v6"perforated drain tile
sloped 1/100 to well
CROSS - SECTION
GPO 830827
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APPENDIX B 2
TOWN OF SHIPROCK, N.MEX. INFILTRATION GALLERIES
N
8" transite pipe-*f |
To plant
weuQ:
10 steel pipe
depth 10
Drainage channel
from uranium mill
6 transite pipe
depth 18
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