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THE
CHURCH ROCK URANIUM MILL
TAILINGS SPILL
A
HEALTH AND
ENVIRONMENTALASSESSMENT
SUMMARY
REPORT
JereMillard
Bruce
Gallaher
David Baggett
Steven Gary
September 1983
NewMexico
Environmental
Improvement Division
Health and
Environment Department
P
Box
9 6 8
Santa
T Q
New Mexico
87504 0968
1000720
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Front
and
Rear Cover Photographs Provided Courtesy of the
U. S. Environmental Protection A g e n c y , Environmental
Monitoring and Support Laboratory. L a s V e g a s , N e v a d a
.
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T H E C H U R C H
R O C K U R A N I U M
M I L L T A I L I N G S S P I L L :
A
H E A L T H A N D
E N V I R O N M E N T A L
A S S E S S M E N T
E x e c u t i v e
S u m m a r y
T h e
l a r g e s t
s ingl e
r e l e a s e o f
l i qu id
r a d i o a c t i v e w a s t e
in the
Ur u t ed
S t a t e s o c c u r r e d at the U n i t e d N u c l e a r C o
r p o r a t i o n u r a n i u m mill n e a r
C h u r c h R o c k , N ew M e x i c o , in
Ju l y
1979 . This d o c u m e n t reports th e
r e s u l t s
of
e n v i r o n m e n t a l
m o n i t o r i n g
c o n d u c t e d
by the N ew
Mexico
E n v i -
r o n m e n t a l
I m p r o v e m e n t D i v i s i o n ( E I D ) s u b s e q u e
n t to the mill
ta i l ings
s p i l l * I n t e r p r e t a t i o n o f d a t a
l e a ds
to the general conclus ion
t h a t
a l t h o u g h the
spill
w as po t e n t i a l l y
h a z a r d o u s .
I ts short-term a nd
l o n g -
t e rm
impac t s o n people a nd
the e n v i r o n m e n t
w e re quite l imi ted . How-
e v e r / t h e d a t a
suggest
that d e w a t e r i n g e f f l u e n t s ( w a t e r f r om u
n d e r -
g r o u n d u r a n i u m mi n e s ) c o n t i n u a l l y p u
mp e d into the Pue rco River m ay
r e p r e s e n t a greater
l o n g - t e r m h a z a r d
t h a n the spil l . Recommenda t i ons
are m a d e r e g a r d i n g
c o n t i n u e d
e n v i r o n m e n t a l m o n i t o r i ng a nd resumpt
ion
o f
n o r m a l
land
a nd w a t e r
u se
a long th e
P u e r c o
R i v e r .
EID
is
also
i s s u i n g tw o t echn ica l reports to p r o v i d e m o r
e
de t a i l ed
in fo rma t i on o n th e
spill
a nd its
im pa c t s .
T h e
spi l l o c c u r r e d ea r ly o n the m o r n i n g of Ju ly
16 when the r e t e n t i o n
dam
f o r
a t a i l ings
p o n d f a i l e d . M o s t o f the
1100 tons
o f
solid
ma te r i a l
r e l e a s e d
wa s
c a u g h t by a small em e rg ency c a t c h m e n t d a m . H
o w e v e r /
m o s t o f th e 94 million ga l lons of l i qu id ente red th e
P u e r c o
R i v e r .
T he
a c i d i c ,
s a l i n e , a nd
r ad i o ac t ive w a s t e flowed
d o w n the
Pue rco R i v e r
c h a n n e l t h r o u g h G a l i u p , N ew
M e x i c o ,
a nd into
A r i z o n a , w h e r e
e v a p o r a -
t ion
a n d
seepage
into the
s t r eam
be d
c a u s e d flow to cease. The spill
p r o m p t e d e n v i r on m e n t a l m on i t o r i n g e f
f o r t s by several g o v e r n m e n t a l
a g e n c i e s .
E I D ,
which
began
m o n i t o r i n g u r a n i u m
industry
impac t s
in
1974 ,
e x p a n d e d a nd i n t ens i f i ed
its d a t a
collection
p r o g r a m s f o r
s u r f a c e
w a t e r , g r o u n d w a t e r a n d
air.
In a d d i t i o n , arroyo s e d i m e n t s , v e g e t a
-
t i o n ,
l i v e s t o c k
a n d
s o m e
local
residents
w e r e
tested
fo r
spill
e f f e c t s
by
EID
o r
by
other
a g e n c i e s .
Interpretation
of
EID
sampling
results
and evaluation
of
conclusions
p r e s e n t e d
by other o r g a n i z a t i o n s
leads
to th e fo l lowing c o n c l u s i o n s a n d
r e c o m m e n d a t i o n s .
1. The
U . S . Centers
for
D i s ea s e
C o n t r o l ( C D C ) /
in co o p e r a t i o n with
the C h u r c h R o c k c o mmu n i t y , f o u n d no d o c u
me n t e d h u ma n
co ns um p -
t ion
of
river
w a t e r .
Six N a v a j o ind iv i dua ls mos t l i ke ly exposed to
spill con taminan ts w e r e selected by
th e
CD C
a n d
tested
a t
L o s
Alam os Na t i ona l
L a b o r a t o r y ,
w h e r e they we r e f o u n d to have
a mo u n t s of r ad i o ac t ive m a t e r i a l n o r m a l l
y fo J in the h u m a n b o d y .
Recrtrnmon^fl^
lt
*
*
R e c o m m e n d a t i o n :
No
f u r t h e r ac t ion r e q u i r e d .
a
2 .
Spill im pac ts on
s u r f a c e
w a t e r q u a l i t y
are
no l o n g e r e v i d e n t .
P r e s e n t
s u r f a c e
wa t e r
quality c lose ly resembles prespill cond i t i ons
a n d is de te rmined p r i ma r i l y by
de wa t e r i n g
e f f l u e n t s a n d n a t u r a l
r u n o f f . These
waters
con ta in l eve ls o f
radioactivity
a nd
ce r t a i n
toxic me t a l s that a p p r o a c h o r exceed s t a n d a r d
s
a n d
gu ide l i nes
des igned
to protect the health of p e o p l e , l ivestock
a nd
a g r i c u l t u r a l
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crops. Regardless o f the
source
of contaminants,
Puerco
River
wa te r may
be hazardous
if
used
over several
years as
the primary
source of
drinking
water,
livestock
wa te r
or
irrigation
water .
The
severity of these hazards
is
not well known at this t ime.
Recommendat ions: The Puerco River should not be used as
a
primary
source of water for human consump-
tion/ livestock
watering
or irrigation.
Additional study of dewatering effluents and
natural runoff is
needed
to
better
define
potential hazards associated with prolonged use
of these waters.
3. Testing of livestock
for
radioactivity and toxic
metals
wa s
suffi-
cient
to
permit only
preliminary
conclusions.
Sheep, goats
and
cattle sampled along the Puerco
River
had higher concentrations of
radioactivity
in
bone, liver and kidney
compared
to control
animals. The
CDC
observed that because older animals
seem
to
have higher
levels, the
probable
sources of
the
contaminants
were
dewatering
effluents
and
natural
runoff,
rather
than the
spilL
Recommendat ions: Based
on
limited testing
conducted by the
CDC,
the additional
radiation
risk from con-
sumption of local livestock is small. The risk
is about the same as
-ie increased risk
from
cosmic radiation incurred by moving from sea
level to
5000 feet in elevation. For
persons
wishing to minimize this small additional risk,
consumption
of
liver
and
kidney
should
be
avoided.
To
minimize uncertainty generated by th e
pre-
liminary
results. Church
Rock
area
livestock
should be
further sampled to determine con-
centrations of
radioactivity
and toxic
metals in
edible tissues
and to
re-evaluate
long-term
risks associated with consumption of such
tissues,
4. No
public,
private
or municipal wells
producing water
for
domestic
us e
or
livestock
watering were affected by
the spill.
Wells draw'
ing
water solely
from
sandstone
or
limestone aquifers probablywill
never
be
affected
by
spill
contaminants.
However,
some
EID test
wells drawing
water
from the shallow
valley
sediments produce
water with elevated levels of salinity and radioactivity due to
the
spill. Wlle ground
water
moves slowly
and
contamination is slight
and confined to limited
areas,
other
shallow
wells
may
become
influenced by thespill in the
future.
Recommendations: Public or private wells drawing water from
the
alluvium
should be
tested
annually
by
appropri-
ate authorities for
salinity
and
gross alpha
radioactivity.
Existing drinking watar testing
ii
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p r o g r a m s
c o n d u c t e d u n d e r
t h e f e d e r a l
S a f e
D r i n k i n g
W a t e r
A c t
a r e
a d e q u a t e .
N ew wel l s d r i l l e d in th e P u e r c o
R i v e r
va l l ey
s h o u l d b e d e s i g n e d
to
d r a w w a t e r f r o m s a n d -
s t o n e
o r
l imes to ne
a q u i f e r s . I f a n
a l luv ia l
well
is
n e c e s s a r y , the u p p e r
100 f e e t o f a l luv ium
should be sea led o f f .
5 . The
h a z a r d
a s soc i a t ed wi th inha la t ion
o f
c o n t a m i r a t e d river
sedi-
ments
s u s p e n d e d in
the air as dust
is negligible f o r
loca l
resi-
dents. C o m p u t e r model ing
identified inhalat ion as
the m o s t signifi-
cant p a t h w a y of r ad i a t i on exposure
to m an
f rom the
spil l-
How-
ever, s ampl in g
o f
a i r b o r n e
dust a l o n g the Puerco R i v e r
in
G a l i up
s o o n after the spill showed o n l y b a c k g r o u n d
levels o f radioactivity.
M o r e o v e r ,
o ne
year fo l l owing the
spil l ,
radioactivity
levels in
P u e r c o R i v e r
s ed imen t s wer e r e d u c e d signif icantly
d u e
to
d i l u t i o n
with
u n c o n t a m i n a t e d
river
sediments.
T h e r e f o r e , avo id in g
the
a r r o y o
d u r i n g
w i n d y con d i t i on s is cons ide red to be o f m i n o r i
m p o r -
tance
and not necessary
f o r
the protection of publ ic h e a l t h .
R e c o m m e n d a t i o n : No further
ac t i on
r e q u i r e d .
6. N a t i v e grasses, s h r u b s a n d c o r n samples col
lected
a l on g
th e
Pue rco
R i v e r
con t a in ed concentrations
of radioactivity
that f e l l
within the r a n g e
o f b a c k g r o u n d
v a l u e s . No spill
effects were
evident.
R e c o m m e n d a t i o n : No further
ac t i on
r e q u i r e d .
7 .
N e i t h e r a n ae r i a l
no r
a g r o u n d s u r v e y o f th e
Pue r co
R i v e r
area
detected
any external
p e n e t r a t i n g
( g a m m a )
r a d i a t i o n levels
attribu-
t ab l e
to
the spill*
R e c o m m e n d a t i o n :
N o further ac t i on
r e q u i r e d .
To s u m m a r i z e , th e
spill a f f e c t e d
the P u e r c o River
va l l ey
e n v i r o n m e n t
f o r
a
b r i e f period,
a n d ha d little o r no e f f e c t
o n
the hea l t h
o f
local
residents. Of greater
c o n c e r n
t o d a y
are the
qua l i ty o f
perennial
d e -
w a t e r i n g e f f l u e n t s i n the
Pue r co R ive r an d
the q ua l i t y
o f n a t u r a l r u n o f f
f o l lowing
thunderstorms o r sno wm el t . T h e se w a t e r s ,
a l t h o u g h
no t
c o n s u m e d
by
people,
are avai lable to loca l l ives tock and
h a v e inf luenced
tha quality of sha l l o w g ro und
waters
in som e
places.
T he extent
to
which
radioactive and
chemica l
constituents
of
these waters are
i n c o r -
porated in
livestock
tissue a n d
passed o n to
h u m a n s
is u n k n o w n
a n d
requires
critical
e v a l u a t i o n . EI D has
o b t a i n e d
f u n d i n g
to
study
this
issue. A n additional
con ce rn i s the
potential f o r r e s i d u a l
spill c o n t a m -
i n a n t s
a n d dewatering
e f f l u e n t s to
further de g r a de sha l l ow
g r o u n d
wa:ers. A n o n g o i n g
E I D
study, s c h e d u l e d f o r comple t i on in 1983,
a d
Iresses the effects
of
dewa te r ing e f f l u e n t s a nd possible
control
m e a s u r e s .
Requests fo r cop ies o f this a n d other
EID
reports o n the
C h u r c h
Ro ck
spill
s h o u l d
be addressed
to
the D i r e c t o r o f
th a
E I D ,
P . O . Bo x 968,
San ta Fe. N ew M e x i c o , 87504-0968.
ii i
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TABLE OF CONTENTS
Executive Summary . . . . . . . . . . . . . . . . . . . . . . .
. i
Table
of Contents. . . . . . . . . . . . . . . . . . . . . . . . .
iv
List of
Figures
. . . . . . . . . . . . . . . . . . . . . . . . . . vi
List of
Tables.
. . . . . . . . . . . . . . . . . . . . . . . . . . vi
1.0 INTRODUCTION....................... 1
1 .1 Background
Information
> . . . . . . . . . . . . . . . .
1
1 . 2 Environmental
Monitoring and Regulatory Response . . . 5
1 . 3
Geographic Setting
- , . . . . . . . , . . - . . . . . .
6
2-0 SAMPLE
COLLECTION AND ANALYSIS . . . . . . . . . . . .
10
2 .1 Surface Water.
. . . . . . . . . . . . . . . . . . . . .
10
2 . 2 Ground Water . . . . . . . . . . . . . . . . . . . . .
.
10
2 .3 Soil and
Sediment.
. . . . . . . . . . . . . . . . . . . 10
2 . 4 Air Particulates. . . . . . . . . . . . . . . . . . . .
.
1 4
2 .5 Vegetation and Produce. . . . . . . . . . . . . . . . . 1
4
2 .6
Gamma
Radiation
. . . . . . . . . . . . . . . . . . . .
2 . 7 Livestock Tissue . . . . . . . . . . . . . . . . . . . . 1
5
2.8 UDAD Computer Code. . . . . . . . . . . . . . . . . . 1
5
3.0 EVALUATION
OF
DATA
. . . . . . . . . . . . . . . . . . .
1 8
3 .1 Surface Water. . . . . . . . . . . . . . . . . . . . .
.
18
3.2 Ground
Water. . . . . . . . . . . . . . . . . . . . . .
2 1
3.3
Channel Sediments . . . . . . . . . . . . . . . . . . .
25
3 . 4 Air
Particulates.
. . . . . . . . . . . . . . . . . . . .
25
3.5
Vegetation and Produce. . . . . . . . . . . . . . . . . 27
3.6
Gamma
Radiation . . . . . . . . . . . . . . . . . . . .
27
3.7
Livestock
Tissue . . . . . . . . . . . . . . . . . . . . 21
iv
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4.0 C O N C L U S I O N S
A N D
R E C OM M E N D A T I O N S .
. . . .
4 . 1 I n t r o d u c t i o n .
. . . . . . . . . . . . . . . .
4 . 2
D i r e c t
C o n t a c t . . . . . . . . . . . . . . . .
4 - 3 S u r f a c e W a t e r . . . . . . . . . . . . . . .
.
4 . 4
G r o u n d
W a t e r . . . . . . . . . . . . . . . .
4 . 5
Livestock. . . . . . . . . . . . . . . . . .
4 . 6 A d d i t i o n a l Exposure R o u t e s . . . . . . . .
.
4 . 7 Long Term Radiation Impacts
. . . . . . < .
References
. . . . . . . . < , . . . -
v
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L I S T OF F I G U R E S
Figure
1 . 1
Figure 1 . 2
Figure 1 . 3
Figure 1 . 4
Figure 1 , 5
Figure
2 . 1
Figure
2 .2
Figure 2 .3
Figure 3 .1
Figure 3.2
Figure 3.3
Figure
3.4
Figure 3 .5
Table 2.1
T a b l e 3.1
Table 4.1
Breached UNC
Tailings
Dam * . . . . . . . . . . .
Map of the Puerco
River
Region
. . . . . . . . . .
Uranium
Decay
Chain. . . . . . . . . . . . . . . .
Puerco River
Landscape
. . . . . . . . . . . . . .
Livestockin the Puerco
River
. . . . . . . . . . .
Monitoring
Site Locations . . . . . . . . . . . . .
Schematic Diagram of
ID Monitoring
Well Installation
Stream
Sediment
Core
Sampling. . - . , . . . . .
Initial Surface
Water
Concentrations . . . . . . . .
Surface Water Concentrations Through
Time
. . .-
Comparison
of Chemical Concentrations
in
Contaminated and
Uncontaminated
Wells.......
Water Quality
Changes
in Well"Galiup ". . . . . .
Thorium Concentrations
in Sediment
. . . . . . . .
LIST OF T A B L E S
Samples Co l lec ted
and
A n a l y s e s
P e r f o r m e d
. . . . .
R a d i o n u c l i d e Concentrations in S e d i m e n t
. . . . . .
Rad i a t i o n
D o s e s Calculated by U D A D . . . . . . . .
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1 . 0 INTRODUCTION
1 . 1 Background
Information
Early on the
morning
of
JTuly 1 6 ,
1 9 7 9 , at the
United Nuclear
Corpora'
tion (UNO Church
Rock
uranium
mill/ the
dam for the
south
tailings
pond failed
(Figure
1 . 1 ) , The pond held liquid and
solid
mill was te .
Approximately
94
million
gallons of mll waste fluids and 1100 tons
of
tailings solids were
released. This was the largest single
release
of
liquid
radioactive waste
recorded
m
the United
States and the fifth
largest release of
solid
radioactive waste. Most of the solids
were
caught
by
a
small
emergency
catchment dam,
but the bulk of the liquid
entered Pipeline Arroyo, atributary of the Puerco
River.*
The
spill
materials flowed
down
the
Puerco
River channel
through
the
City of Galiup,
New
Mexico
(Figure
1 - 2 ) . Downstream travel of the
waste
w as
enhanced
by
the flow of 5000 gallons
per
minute of water
continuously pumped into Pipeline Arroyo by routine
dewatering
opera-
tions
at
upstream uranium mines.
Gradual losses to
evaporation
and
infiltration
caused
flow to
cease
near Chambers, Arizona, about 60 air
miles and 100 river miles downstream from the UN Cmll.
Released tailings liquid
contained
a
number of
radioactive
and chemical
constituents that posed
potential
threats to public health and
the
en-
vironment. Of particular concern were 1 ) radionuclides present
in
uranium ore
(Figure
1 . 3 ) / primarily uranium-238, thorium-230, radium-
226 ,
Iead-210
and
polonium-210, 2)
toxic metals
including
elemental lead/
m o l y b d e n u m ,
a r s e n i c
a n d
s e l e n i u m ,
3)
a c i d i t y a n d
4 )
h i g h
leve ls
o f
d i s s o l v e d salts,
p a r t i c u l a r l y s u l f a t e .
A s i d e f r o m d i r e c t
c o n t a c t /
th e
t a i l i n g s spill
c o u l d a f f e c t
publ ic
h e a l t h
t h r o u g h the f o l l o w i ng m e c h a n i s m s :
1 . Wate r -borne contaminants in
the
Puerco
River may
infiltrate
into the
ground and impair the quality
of
shallow ground
water.
Because ground water moves
slowly, such
degradation
could remain
undetected
until a private well
is affected.
2 . L ives tock cou ld ingest con tamina ted
s e d i m e n t s
by d r i n k i n g
w a t e r
f r om the P u e r c o
R i v e r .
Ove r
a
long
pe r i od
of
t i m e ,
this m ay r e s u l t
in
hazardous
a c c u m u l a t i o n s o f
r a d i o n u c l i d e s o r
metals
in
animal tissues.
These
tissues
could
then
be
con-
sumed by people,
3. Contaminated sediments from
the Puercc River may
be sus-
pended as dust and inhaled by
local
residents or deposited on
vegetation and consumed
by
livestock,
* The Puerco
River
originates
at
the continental divide and f lows
westward
through Galiup, eventually joining the Colorado River system
in
Arizona.
It should not be
confused
with the
Rio Puerco which
originates near Cuba. New Mexico
and joins
the
Rio
Grande-
I
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-
8/10/2019 06-1000720
10/41
F i g u r e
1 . 2 . M a p
o f t h e
P u e r c o
R i v e r
R e g i o n
no* ~
1
3d*- Js^V
INDIAN
RESERVATION
S
^
-
^
/
OUCK
.
1 1
-rf
'
J
-bEB-1
CMAia?efl-i
35
~~
PjX^
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