AN INTERIM REPORT
ON AIRBORNE FLUORIDES IN
GLACIER NATIONAL PARK
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AN INTERIM REPORT
ON AIRBORNE FLUORIDES IN
GLACIER NATIONAL PARK
ENVIRONMENTAL PROTECTION AGENCY
' ' OFFICE OF GENERAL ENFORCEMENT
DIVISION OF STATIONARY SOURCE ENFORCEMENT
JUNE 1972
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ACKNOWLEDGEMENTS
TECHNICAL CONTRIBUTORS
Kirk E. Foster
Division of Stationary Source Enforcement
George A. Cleeves
Division of Meteorology
Dr. Ibrahim J. Hindawi
Charles D. Robson
Division of Ecological Research
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CONTENTS
PAGE
INDEX OF FIGURES iii
INDEX OF TABLES iv
SUMMARY 1
INTRODUCTION 6
DESCRIPTION OF SURVn^TODIES..,.....:.. 7
Forest Service Studies .., 7
NAPCA Studies 8
University of Montana Studies 9
DESCRIPTION OF AREA 9
Geography 9
Climatology 10
METEOROLOGICAL STUDY 11
COLLECTION OF WIND DATA 12
Upper Winds ; 12
Lower Winds 13
NIGHTTIME AIR MOVEMENT 14
DAYTIME AIR MOVEMENT 15
SEASONAL CHANGES 16
REPRESENTATIVENESS OF STUDY PERIOD 17
SUMMARY 18
AMBIENT FLUORIDE CONCENTRATIONS 18
STATIC MEASUREMENTS '. 19
COMPARISON OF PLATE AND LIMED PAPER RESULTS 21
CONTINUOUS 'FLUORIDE MEASUREMENTS 23
SUMMARY 26
VEGETATION STUDY 27
EXPOSURE OF SELECTED PLANT SPECIES 28
SURVEY OF INDIGENOUS VEGETATION 32
Visible Injury 33
Histological Examination of Injured Needles 34
Chemical Analysis 35
SUMMARY 36
REFERENCES 37
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APPENDIX A. CONSULTANT REPORT 38
APPENDIX B. FLUORIDATION MEASUREMENT DATA 47
APPENDIX C. METEOROLOGICAL DATA 48
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INDEX OF FIGURES
FIGURE PAGE
1 Orientation Map of Anaconda Aluminum Plant - Glacier
National Park Area 1 Oa
2 Location of Meteorological Observation Stations 12a
3 Dominant Wind-Flow Patterns Measured June through September
1970 at Blankenship Station (No. 2) 14a
4 Dominant Wind-Flow Patterns Measured June through September
1970 at DeMerritt Station (No. 5) 14b
5 Dominant Wind-Flow Patterns Measured June through September
1970 at Rose Station (No. 3) 14c
6 Simplified Drawing of Typical Midmorning Wind-Flow Patterns in
Upper Flathead Valley 14d
7 June, July, and August Wind Rose for Kali spell, Montana
(1950 through 1959) 16a
8 Location of Fluoridation Plate Exposure Sites 19a
9 Distribution of Measured Fluoridation Rates 20a
10 Extrapolated Distribution of Fluoridation Rates Reflecting
Topographical and Meteorological Influences 21a
11 Location of Continuous Fluoride Monitoring Stations and Plant
Exposure Shel ters 22a
12 Distribution of Fluoridation Rates Shown in Figure 9 Expressed
as Hydrogen Fluoride Concentrations 26b
13 Average Fluoride Accumulation in Needle Tissue of Three Pine
Varieties Exposed from June 25 to October 21, 1970, at Four
Locations 30a
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IV
INDEX OF TABLES
TABLE ' PAGE
1 Summary Means of Percent Frequencies of Occurrences of Wind
Directions in Summer Measured at Two National Heather Service
Upper Air Stations Nearest to Columbia Falls, Montana, 1961
through 1965 12b
2 Fluoridation Rates Measured in Glacier Park and Surrounding
Areas Using the Plate Method 19a
3 Comparison of Fluoridation Rates Measured by Plate and Limed
Paper Methods 22b
4 Fluoridation Rates Measured by Plate Method and Converted to
Equivalent State of Montana Units 22c
5 Summary of 12-hour Gaseous and Particulate Fluoride Concentra-
tions Measured in Glacier Park and Surrounding Area, June 26
to October 23, 1970 24a
6 Average Fluoride Concentrations Measured during Different
Periods in Glacier Park and Surrounding Area .'....25a
7 Fluoridation Rates Shown in Table 2 Expressed as Hydrogen
Fluoride Concentrations 26a
8 Fluoride Accumulation in 1969 and 1970 Needles of White,
Ponderosa, and Scotch Pines Exposed from June 25 to October 21,
1970 31a
9 Fluoride Accumulation in Alfalfa Leaves and Stems Exposed in
1970 Study 31b
10 Fluoride Accumulation in Chinese Apricot Leaves and Stems
Exposed in 1970 Study 31 c
11 Fluoride Accumulation in Gladiolus Leaf Tissue Exposed from
June 25 through September 14, 1970 31d
12 Fluoride Accumulation in Vegetation Samples Collected in Or
Near Glacier National Park 35a
B-l Location and Elevation of Fluoridation Network Sites 47a
B-2 Monthly Fluoridation Rate Measurement Results 47b
C-l Meteorological Data Applicable to the Glacier Park Region 48a
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AN INTERIM REPORT
ON AIRBORNE FLUORIDES
IN GLACIER NATIONAL PARK
SUMMARY
Anaconda Aluminum Company's reduction plant began operations at
Columbia Falls, Montana, inT935, In 1957 flora in the vicinity of the
plant began to show foliage..ijnjvzy that Is .sjropomatic of excessive accumu-
lation of fluoride, an air contaminant emitted from the electrolytic
reduction cells used in primary aluminum smelting.
During the years between the initial observations of suspected
fluoride damage and 1968, when damage to pine trees became noticeably
more widely spread in the area, Anaconda Aluminum twice expanded the plant.
Following the last expansion in 1968, other areas around Columbia Falls
and even areas in the southwestern part of Glacier National Park, which
is 6 miles northeast of the aluminum plant, were found to have visible
damage to flora.
In 1970 the U. S. National Park Service, concerned that fluoride
emissions from the aluminum plant were being carried into G^cier National
Park by prevailing wind currents in concentrations harmful to the Park
environment, requested the assistance of the National Air Pollution Control
Administration, a predecessor of the Environmental Protection Agency
(EPA), in assessing the effects of airborne fluorides on vegetation and
wildlife in the Park. The National Air Pollution Control Administration
(NAPCA) in cooperation with other Federal and state agencies conducted
field studies in and near Glacier National Park during 1970. This is an
interim report of the results of the NAPCA study prior to issuance of a
final EPA technical report.
The NAPCA studies included meteorological analyses, measurement of
ambient fluoride concentrations, and assessment of the effects of fluorides
on special test vegetation and indigenous flora within the Park. NAPCA
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also sponsored a more extensive study of vegetation1and wildlife conducted
by the University of Montana. The results of the 6-month University of
Montana study are described in EPA Contract Report CPA 70-109 and will be
included in the final EPA report. The results of the portion of the
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study conducted by NAPCA are summarized as follows: )
METEOROLOGICAL STUDY
Observations of the wind flow at various locations and elevations
indicated two distinct air flow patterns which affect the movement of
airborne fluorides emitted at the aluminum plant. The upper winds, those
at or above mountaintop level, were found to be most prevalent from the
southwest during the summer. The lower level winds, those from ground
level in the valleys to about mountaintop level, tended to reverse direc-
tion between day and night. These wind patterns interact to cause the
fluoride emissions to be transported toward Glacier National Park a major
portion of the time.
In daytime, prevailing up-valley air flow coupled with southwesterly
winds aloft are conducive to the movement of fluorides across Teakettle
Mountain and northeasterly into the Park. The nighttime down-valley flow
is conducive to movement of fluorides from the aluminum plant south and
southwestward into Columbia Falls and along the lower valley of the
Flathead River.
The highest concentrations of fluorides are most likely to be carried
into the Park during the daytime, principally during the midmorning hours.
The nocturnal flow in the lower Flathead Valley tends to be sluggish and
causes fluorides emitted during the nighttime hours to accumulate in the
valley. After sunrise, plant effluents that have accumulated in the
lower valley combine with continuing plant emissions and mix in a
deepening air layer until this layer reaches the top of Teakettle Mountain
where the effluents are entrained into the upper wind flow. The effluents
are conveyed by the prevailing southwesterly upper wind over the upper
Flathead Valley and intercept the mountainous terrain within the Park
at the height of the upper wind level. Downward mixing of the air mass
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in the steep valleys within the Park is retarded during the morning by deep
shadows that prevent solar heating of the ground. By midday more vigorous
vertical mixing of the air mass in the upper valley causes a reduction of
pollutant concentrations within the Park.
Summer through early fall appears to be the period of greatest
effluent transport toward the Park. Favorable conditions for this move-
ment are the longer daytime hours and the prevailing southwesterly winds.
During other seasons winds are usually stronger so that greater disper-
sion takes place causing a general reduction of ambient concentrations.
AMBIENT FLUORIDE CONCENTRATIONS
Ambient fluoride concentrations were detected by two different
methods: (1) monthly statis measurements made by exposing chemically
treated filter paper at 37 sites, and (2) dynamic measurements of 12-hour
gaseous and particulate concentrations made at a few sites using
electrically operated samplers.
The static measurements or the fluoridation rates, an index of gaseous
fluoride concentration over a period of time, were found to decrease
rapidly as distance from the aluminum plant increased except in the
northeasterly direction. The influence of prevailing wind patterns and
the higher ground elevations o-c exposure sites in Glacier National Park
are factors that contribute to the elevated fluoridation rates that were
measured ten or more miles from the plant in the northeasterly direction.
Fluoride readings at several sites within the Park consistently exceeded
the State of Montana air quality standard. For example, the average
value for the sampling station on Apgar Mountain was in excess of the
state standard by a factor of nearly two.
The results of static sampling definitely show that parts of Glacier
National Park, especially the upper slopes of the Apgar Mountain, are
exposed to relatively high, long-term levels of atmospheric fluoride.
Consideration of the meteorology, topography, and geography strongly
suggests that high elevations elsewhere in the Park and the Flathead
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National Forest are similarly exposed to high ambient fluoride concentra-
tions the source of which is the aluminum plant at Columbia Falls.
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Gaseous and particulate fluoride concentrations were continuously
measured at four sites at lower elevations along the Park boundary where
electric power was available. Twenty-four hour average gaseous fluoride
readings exceeded the State of Montana Air Quality Standard only once
during the study period. More exposed locations at higher elevations in
the Park probably experience short-term concentrations in excess of state
standards more frequently.
The 24-hour total fluorides (gaseous and particulate) did not vary
appreciably between the different months of the study. However, gaseous
fluorides decreased while particulate fluorides increased during the course
of the study. The average of the 12-hour daytime measurements was generally
higher than the average of measurements collected during nighttime hours
substantiating the study finding that daytime wind patterns are more con-
ducive to movement of airborne fluorides into the Park.
VEGETATION STUDIES
Extensive collection of vegetation and animals in and near the Park
was conducted by study participants for use in macro- and microscopical
examination and chemical analysis. Supplementing these studies, NAPCA
specialists gathered vegetation specimens twice during the study in the
more readily accessible areas of the Park.
Plants especially sensitive to fluorides were exposed to ambient
air in enclosed plant shelters at three sites. Plant shelters equipped
with filters to remove particulate and gaseous fluorides were operated
as control shelters. Plants were exposed to unfiltered ambient air in
other shelters. Plants selected for the study included alfalfa,
apricot trees, gladiolus, and several pine species. Although test
procedure difficulties hampered interpretation of results, a greater
amount of fluorides accumulated in the vegetation exposed to ambient
air than in plants exposed to filtered air. Moderate tip burn was
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observed on sensitive apricot trees and gladiolus plants at the conclusion
of the 16-week exposure period.
Field observations by a NAPCA plant pathologist and an independent
consultant revealed visible injury had occurred to sensitive conifers and
other vegetation growing in and near the Park. The older needles of
ponderosa pine growing in an exposed location on the western slope of Apgar
Mountain showed considerable tip burn. Other coniferous species in the
area had severe foliar necrotic lesions on the 1968 and 1969 needles.
The variability of visible damage to vegetation within the Park
suggests that location, topography, and meteorology are key factors in
the exposure to excessive fluorides. For example, some areas near the
west boundary of the Park, presumably protected by topography or location
from exposure to airborne fluorides, appeared free of foliar injury, but
clearly visible tip necrosis was noted on older needles of sensitive white
pine growing in areas situated deep within the interior of the Park along
the frequent path of the effluent plume from the aluminum plant.
Histological examination of injured needles from conifers exhibiting
tip burn symptoms showed extensive pathological changes in the needle
tissue which indicated that the entiology of the needle necrosis was of
a chemical nature. These changes could not have been caused by insect
infestation, disease, or winter damage.
Injury symptoms on conifers observed in 1970 in all cases were con-
fined to the older needles--1967, 1968, and 1969. Although the current
year needles of the affected trees did not show injury symptoms, it is
possible that after longer exposure times these needles may also show
visible injury. The extent and severity of burn on 1967 through 1969
needles strongly suggest that serious and irreparable damage would have
been caused to the Park flora in future years if fluoride emissions had
been allowed to continue at the pre-1971 level.
The assessment of foliar injury and probable causative agent was
verified by a consultant associated with the University of California .
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Research Center at Riverside, California. Chemical analysis of fluoride
content of necrotic conifer needles collected in the Park were made at the
Riverside laboratory. The analysis results indicate significant fluoride
content which substantiated the consultant's initial conclusions that the
needle tip necrosis observed on older growth of sensitive pines in Glacier
National Park was produced by excessive ambient levels of fluorides.
INTRODUCTION
The Anaconda Aluminum Company dedicated a hew aluminum reduction
plant at Columbia Falls, Montana, in August 1955. Although officials of
the company insisted that injury to indigenous flora and fauna caused by
fluorides emitted in the reduction process would be negligible, the U. S.
Forest Service found in 1957 that some of the more susceptible flora in
the vicinity of the aluminum plant were being visibly damaged. Little
evaluation or research into extent of damage was accomplished until late
1969 and 1970, however.
During the years between the initial observations of suspected fluoride
damage and the more extensive studies, Anaconda twice expanded the plant.
Following the last expansion in 1968, dead and dying trees were observed
over the entire west face of Teakettle Mountain, which is directly east of
the aluminum plant. Other areas around Columbia Falls, east of Teakettle
Mountain, and even areas in the southwestern part of Glacier National Park,
which is 6 miles northeast of the aluminum plant, were also found to have
visible damage to flora.
Anaconda reported that fluorides were emitted during 1969 and early
1970 at the rate of nearly 7600 pounds per day-(lb/day) but were reduced
to about 5000 Ib/day by September 1970. By early May 1971, emissions
were reported to be 2500 Ib/day.
National Park Service officials became concerned that fluoride emis-
sions from the aluminum plant were being carried by prevailing wind
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currents into Glacier National Park in sufficient concentrations to harm
Park ecology. In 1970 they requested the assistance of the National Air
Pollution Control Administration (NAPCA) in assessing the effects of air-
borne fluorides on vegetation and wildlife in the Park.
In addition to the studies by NAPCA, several other agencies began
similar studies to assess'fluoride damage around and near the aluminum.
plant. These included the U. S. Forest Service, the University of
Montana, and several consultants under-contract "to NAPCA. The activities
of all agencies participating in the studies were coordinated into a
unified survey plan to achieve a uniform appraisal of the effects of
airborne fluorides in Public lands in the Flathead National Forest and
Glacier National Park.
This interim report contains the results of that portion of the overall
survey that was directly carried out by the NAPCA staff and is issued as
a source of information and guidance based on preliminary findings. It
is intended for use by the National Park Service in their immediate
consideration of the welfare of the Park. The final conclusions and
recommendations will be included in the final , comprehensive report to
be issued by the Environmental Protection Agency.
DESCRIPTION OF SURVEY STUDIES
The various studies conducted by the survey participants were designed
to provide information on several different aspects of the effects of the
atmospheric fluorides. The study activities were divided between the
agencies, and individual responsibility was assigned to prevent duplication
of effort and to insure as complete an assessment as possible within the
available study resources. The activities undertaken were as follows:
Forest Service Studies
The U. S. Forest Service began an evaluation of fluoride damage on
National Forest lands in the vicinity of Columbia Falls in 1969. In
cooperation with the NAPCA study effort, the Forest Service extended its .
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study to include areas of Glacier Park nearest the aluminum plant that were
susceptible to fluoride damage.
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In these studies, emphasis was placed on fluorides in vegetation,
insects, and surface water. A plan based on a system of plots located at
varying distances on predetermined radii extending from the aluminum plant
was used for the collection of vegetation and insect samples.
Visible damage appearing on vegetation samples was measured and
chemical analysis for fluoride accumulation was made. Insects were
analyzed for fluoride content and were monitored for discernible dif-
ferences in population levels attributable to excessive fluoride exposure.
Surface water was analyzed for fluoride content.
The results of the Forest Service studies have been published but
will be included in the final report of the overall survey.
NAPCA Studies
NAPCA's investigation was conducted concurrently with the Forest
Service studies but was designed to provide additional information such
as meteorological and air quality data. The NAPCA studies included
determining the predominant pattern of movement of airborne fluorides
from the aluminum plant to the Park, measuring ambient concentrations of
fluorides in the Park, and assessing effects of fluorides on indigenous
flora within the Park. Each of these phases of the overall survey are
reported in separate sections of this report.
The Division of Abatement of NAPCA, assisted by the National Park
Service, Montana State Health Department, the Environmental Studies
Laboratory of the University of Montana, and several consultants, per-
formed the required studies. Extensive collections of vegetation and small
animal specimens in and near the Park area were gathered for macro- and
microscopical examination and for chemical analysis. Selected plants
that are sensitive to fluorides were exposed to filtered and untiltered
ambient air in special plant shelters. To verify the diagnosis of
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visible fluoride injury made by the other participants, observations of
damage were made by NAPCA and a consultant.
Assessment of foliar injury and characterization of the probable
causative agent involves considerable subjective evaluation. An indepen-
dent investigator, Dr. 0. C. Taylor, Horticulturist, of the Air Pollu-
tion Research Center, University of California, was retained by NAPCA
to make observations of any vegetation injury and conduct associated
chemical analyses in his laboratory. The findings' of Dr. Taylor are
included as an appendix to this report.
University of Montana Studies
Dr. C. C. Gordon, Professor of Botany, University of Montana, was
awarded a NAPCA contract to perform an area-wide survey of the condition
of vegetation in the Park area. Samples of vegetation were first collected
on a random basis to identify areas of the Park showing visible damage on
conifers. More extensive vegetation sampling was then conducted in these
areas. Specimens of wildlife were also collected in the areas of suspected
fluoride contamination.
Conifer needle tissue and animal tissue were examined histologically
for microscopic symptoms of fluoride injury, and chemical analysis was
performed. Attention was given to the possible accumulation and buildup
of fluorides within the ecological food chain.
A draft of the University of Montana final report is on file at EPA
but is, as yet, unpublished.
DESCRIPTION OF AREA
Geography
Glacier National Park straddles the Continental Divide from the
Canadian Border to Marias Pass, 60 miles to the south. This section of
northwestern Montana includes some of the more spectacularly rugged
mountain country in North America. From peaks well above 10,000 feet,
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the mountains pitch down to rivers and lakes that are nearly 3,100 feet
above mean sea level CMSL).
The Flathead River system, shown in Figure 1, drains the western side
of the Divide and forms the Park's western boundary. This drainage area
is subdivided into an "upper valley" with narrow tributary canyons and
swift streams and a "lower valley" more than 15 miles wide through which
the river meanders to Flathead Lake, approximately 8 miles southeast
of Kali spell, Montana. The river leave the upper valley through Badrock
Canyon, which also constitutes the south wall of Teakettle Mountain. The
Anaconda aluminum plant is situated a mile down-river from Badrock Canyon
between the river and the west face of Teakettle Mountain.
Although there are several ranches in the upper valley, the area is
primarily Park and National Forest land with a limited road system along
the rivers. The lower valley is relatively broad and flat with a road
network that follows section and quarter-section survey lines. In addition
to ranching and the ranch-related service industries, a thriving lumber
industry processes timber from the surrounding mountains and from the
upper valley. Low-cost electric power has attracted some industry,
principally the aluminum plant at Columbia Falls.
Climatology
The climate of the Flathead River Drainage Area may be classed as
Alpine with a strong maritime modification. The range of climate extends
from that of the permanently snow-covered peaks to that found along the
shores of Flathead Lake where small fruit orchards flourish in a 3-month
frost-free belt.
The higher mountains are estimated to receive as much as 150 inches
of annual precipitation, primarily as snow, on their west-facing slopes.
Snow depths in excess of 10 feet accumulate during the winter, and, while
the shores of Lake McDonald (3100 feet above MSL) are snow-free by May,
drifts may remain on the lower north-facing mountain slopes into August.
Snow-covered glaciers are permanent features of the high slopes of some peaks,
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Figure 1. Orientation map of Anaconda Aluminum Plant -
Glacier National Park area.
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Significant differences in temperature, precipitation, and wind flow
are associated not only with elevation but also with the orientation of
the mountainsides, the proximity of ridge!ines, and the location of the
larger lakes relative to a given location. Flathead Lake, because of its
size and depth, normally contains a large open water area throughout
the winter. This heat source exerts a strong modifying influence on the
climate of the lower valley; /Selected climatoTogical summary data are
presented in Table C-l.
Marias Pass is included in Table C-l because it lies at approximately
the same elevation as the saddle in Teakettle Mountain and the Apgar Lookout
overlooking West Glacier. Although this pass is well-removed from the
area of study, its climatic data are thought to be representative of
similarly exposed locations under study. Much of the Park area under
study is, however, higher than Marias Pass and has a correspondingly shorter
growing season and a more severe climate.
METEOROLOGICAL STUDY
A meteorological study of air flow was performed to obtain information
on principal wind trajectories in the area and their influence on trans-
port and dispersion of air contaminants from the aluminum plant. Knowledge
of the local air flow pattern .is essential in understanding the problem
and in evaluating the data generated by the air quality and vegetation
studies.
Two air flow patterns in this mountainous area must be considered.
The upper wind, as influenced by the major geographic features, reflects
the general motion of the atmosphere near mountaintop level. The wind
is measured periodically by free balloon flights, normally scheduled at
noon and midnight Greenwich time. None of these balloon flights originate
within the study area covered by this report, however. The low-level
wind pattern is determined by the interaction of the upper wind with the
localized mountain and valley winds, the latter often subject to pro- .
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nounced changes during a day. Fortunately, low-level winds may be con-
tinuously monitored by surface-mounted wind recording instruments.
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COLLECTION OF WIND DATA \
Upper wind data were obtained from the National Weather Service's
Upper Air Network at Spokane, Washington (200 miles west of the Continental
Divide) and from Great Falls, Montana (80 miles east of the Divide). No
additional upper wind data were obtained in this study.
Surface wind data, recorded hourly at the Kali spell Airport by the
National Weather Service, were supplemented by data from wind recording
instruments operated from mid-June through late December of 1970 at
three sites in the area. The location of these sites and their rela-
tionship to nearby topographical features is shown in Figure 2.
The wind sensors were exposed 32 feet above ground in open pasture-
land except at Station 3 where a 40-foot mast barely reached above the
surrounding lodgepole pines. Abstracts of data from these wind records
are included in the following analysis and a complete tabulation will be
provided in the final report.
Upper Winds
The National Weather Service Upper Air Network of stations obtains
wind measurements twice each day at Spokane, Washington, 200 miles west-
southwest of the study area, and at Great Falls, Montana, 80 miles to
the east-southeast. The frequency of occurrence of wind direction for the
summer months of 1961 through 1965 are shown in Table 1. At Spokane,
the winds 1500 meters above mean sea level (m MSL) are predominantly from
the southwest. At Great Falls, on the eastern side of the Continental
Divide, the winds at 2000 m MSL are slightly stronger and more westerly.
In the absence of winds aloft data for Glacier National Park, it is
difficult to accurately define the bahavior of winds at and above the
general ridge level (about 2000 m MSL). Climatological values of the
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Table 1. SUMMARY MEANS OF PERCENT FREQUENCIES OF OCCURRENCES OF WIND DIRECTIONS
IN SUMMER MEASURED AT TWO NATIONAL WEATHER SERVICE UPPER AIR STATIONS
NEAREST TO COLUMBIA FALLS, MONTANA, 1961 through 1965a
Direction
N .
NNE
NE
ENE
E
ESE
SE
SSE
S
ssw
sw
WS.W
w
WNW
NW
NNW
Calm
Great
2
4 a.m
4.3
2.7
2.7
4.0
4.5
3.4
4.5
2.0
6.3
6.7
7.2
16.1
19.7
8.9
4.7
2.2
0.2
Frequency,
Falls, Montana
,000 m MSL
4 p.m.
4.2
3.3
4.9
5.4
4.7
5.1
2.5
1.3
2.7
4 2
7.6
14.5 '
19.0
7.8
8.0
4.2
0.4
Spokane, Washington
1,500 m MSL
4.a.m. 4 p.m.
2.5 4.3
4.9 3.8
3.8 4.5
7.4 3.2
3.6 2.7
2.9 0.2
2.5 1.8
2.0 0.9
2.9 3.4
7.4 11.5
26.8 28.4
15.4 18.3
8.7 8.4
4.3 2.9
3.1 2.9
1.6 2.3
0.2 0.5
aFrom the available tabulations,6 the level closest to the flow over
Columbia Falls and Teakettle Mountain is presented for each station.
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700 millibar (mb) pressure heights (about 3000 m MSL) indicate that during
the summer the prevailing winds should be west southwest to southwest
in the vicinity of the study area. Downward extrapolation of those winds
for 1000 meters should give a more southerly component to the winds near
the ridge line because of the influence of friction nearer the ground.
The magnitude of the direction change cannot be accurately stated because
of the roughness of the terrain, but a change of 10 to 20 degrees is a
reasonable estimate.
The winds aloft appear to follow expected meteorological patterns
on the western side of the Continental Divide. The bahavior of large-
scale atmospheric motions when encountering a mountain chain is discussed
in most basic dynamical meteorology texts. The usual behavior is for
the winds on the downs!ope side to be directed to the right of the wind
direction on the upslope side. This appears to be the reason for the
more frequent westerly winds at Great Falls. The magnitude of the
turning is partially dependent upon the wind speed. In winter when winds
are usually stronger, the winds aloft at Spokane are still predominantly-
from the southwest, but at Great Falls the frequencies of occurrence of
west and west-northwest winds increase to 28.6 and 19.5 percent,
respectively.
Lower Hinds
Data obtained from the three NAPCA wind recording stations (Figure 2)
indicated marked differences which appear to be caused by the typical
mountain and valley local wind flow patterns. .Seasonal changes were also
apparent. The summer diurnal wind pattern at low levels is described below;
thereafter fall, winter, and spring variations are briefly mentioned.
Because Station 2 was situated near the mouth of the Middle Fork
River, upslope winds were most frequently registered as upstream flow.
During downslope drainage situations , flow from the northwest along the
Middle Fork often alternated with that from the North Fork causing
either northv/est or northeast winds during much of the night. At other
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times, cool air drainage from adjacent mountains occurred. Dominant wind
flow patterns measured during the summer of 1970 at this station are shown
in Figure 3.
The persistent west wind at Station 3, shown in Figure 4, was attributed
to drainage from the Bailey Lake region and to daytime channeling when
southerly or westerly winds in the lower basin of the Flathead caused
outflow around the north shoulder of Teakettle Mountain.
Nighttime drainage of the large area of higher country above Badrock
Canyon results in very dominant northeast winds.at Station 5, as depicted
in Figure 5. The winds persist well into the daytime before the upslope
flow from the valley to the mountains begins.
Kalispell Airport wind pattern for the summer season is presented in
Figure 6. The frequent south and south-southeast winds are attributed
to the daytime up-valley and lake effects. The equally frequent winds
from the north through northeast sector must be ascribed to nighttime
down-valley flow toward the lake.
NIGHTTIME AIR MOVEMENT
The lower Flathead Valley from Columbia Falls south to Flathead
Lake is protected to a large extent from the winds aloft by the mountains
that surround it on three sides leaving it relatively open only to the
south. During nights when radiational cooling at ground level is effective,
the air near the ground cools rapidly, becomes more dense, and begins to
flow along the ground toward lower elevations. Effluents emitted from
industrial operations are warm, and rise until they are no longer buoyant
but remain below the crest of the confining mountains.
The air from the upper valley, which is shown in Figure 4, drains
through Badrock Canyon and passes Station 5 as a northeasterly wind.
This down-valley wind becomes apparent at 10:00 p.m., reaches a maximum
frequency near sunrise of 67 percent, and usually dissipates shortly
after noon. The same air current is apparent at the airport where it
-------
14a
N
NE
CO
O
Q
? SE
X
o
&
1 s
UL
Z
O
o
UJ
cc
O
<5
20
20-
TIME OF DAY
Figure 3. Dominant wind-flow patterns measured June through September, 1970
at Blankenship Station (No. 2). Iso-lines show percent occurrence of wind di-
rections at indicated times.
-------
14b
i
CO
D
I
O
O
cc
o
LU
CC
N
NE
SE
W
NW
20 —
<5
<5 \
CO
<
LU
in
H
ID
CO
<
LU
<5 )
s -v
! ^x A
i .icrr-ti—i-j^i
I <5
68 10 12
-«—r p.m.
4 6 8
- a.m.
10 12
8 10 12
4 6
p.m.
TIME OF DAY '
Figure 4. Dominant wind-flow patterns measured June through September, 1970 at DeMerritt
Station (No. 5). Iso-lines show percent occurrence of wind directions at indicated times.
-------
14c
CO
O
CO
Q
I
U
O
cc
U-
O
uu
DC
N
NE
SE
2 sw
w
NW
<5
01
V)
cc
CO
CO
1-
17
I
6 8
-a.m. —
10
12 2
10 12
• a.m.-
p.m. »-j««
TIME OF DAY
Figure 5. Dominant wind-flow patterns measured June through September, 1970 at Rose
Station (No. 3). Iso-lines show percent occurrence cf wind directions at indicated times.
-------
___ _
Figure 6. Simplified drawing of typical midmorning wind-flow patterns in
Upper Flathead Valley.
-------
:
is more diffuse and northerly because of the inclusion of additional air
currents as it spreads over the flat valley floor to Flathead Lake.
DAYTIME AIR MOVEMENT ' \
\
i
At sunrise the west sides of these two valleys with their east-facing
slopes are warmed rapidly while their opposite valley walls, which remain
in deep shadow, are cool. As vertical currents develop over sun-heated
slopes, cooler replacement air from the down-valley flow is entrained and
wind directions consequently shift.
As direct sunshine progresses onto the broad lower valley floor, the
related developing vertical currents progress upward into the blanket of
stagnant air that accumulated during the night and mix the air downward to
the surface as well as upward. Mixing continues to deepen until the
mountaintop levels are reached and the valley air begins to be entrained
by the prevailing upper winds.
The wind direction shift toward the slopes heated by the early
morning sun is most striking at Station 3. (See Figure 4) This
north-easterly wind appears to blow from the shaded side of the Apgar
Mountains to the sunny side of Teakettle Mountain between the hours of
7:00 a.m. and 1:00 p.m., reaching 50 percent frequency near 11:15 a.m.
During the morning, this flow of clean air into the upper valley shields
the east face of Teakettle from effluents being carried aloft.
Up-valley wind flow develops and the mixing layer deepens until air
.from above the top of Teakettle is mixed with surface air throughout the
upper valley during much of the afternoon. By this time, the nighttime
stagnant air has already been carried away from the lower valley by
the prevailing winds, and only current emissions are mixed through the
deep layer of air to the surface in the upper valley so that the higher
concentrations do not reach the floor of the upper valley.
The overall wind pattern when upper winds are from the southwest and
the lower valley convection has broken through into the upper flow is
-------
16
i /
shown pictorially in Figure 7. The viewer looks to the northeast across
Teakettle Mountain and the Upper Flathead Valley to Lake McDonald. Direct
sunshine has not penetrated the valleys in sufficient strength to reverse
the down-valley winds along the river although upslope flow exists on the
sunny, east-facing slopes and the down-valley flow has turned somewhat
toward these slopes. In the upper valley beyond teakettle Mountain, the
clean air flowing down along the rivers shields the surface from fluoride-
laden air entrained in the upper level winds. This is the preponderant
pattern during the summer.
On days when southwest upper winds prevail, the highest concentrations
of fluoride are carried into the Park during the forenoon. At sunrise the
previous night's accumulation of plant effluents plus the current emissions
are being held within the lower valley and mixed in a deepening layer until
this layer reaches and is entrained by the upper flow. The lower valley
effluents are then carried in the upper flow over the upper valley and
into the Park where they intercept terrain elements common to the height
of the effluent plume. As convective activity increases, more complete
mixing occurs to higher levels of the atmosphere and dilutes the concentra-
tion of the remaining effluents.
With the increase in surface heating, the typical up-valley wind
pattern develops in both the upper and the lower valleys and is augmented
by a lake-to-land breeze from Flathead Lake.
SEASONAL CHANGES
The southwest through west-southwest daytime winds above Teakettle
Mountain are of major importance, because they apparently carry the
effluents from the aluminum plant at Columbia Falls to the Park. These
transport winds, described below, are estimated from considerations pre-
sented in the earlier section on "UPPER WINDS."
Summer Fall Winter Spri ng
Average Average Average Average
Frequency Speed Frequency Speed Frequency Speed Frequency Speed
% mph % mph % mph % mph
47 17 40 24 46 28 41 25
-------
16a
W
4-7 8-12 13-18 >18
MILES PER HOUR
5
PERCENT FREQUENCY
Figure 7. June, July, .and August wind rose for Kalispell,
Montana (1950 through 1959)
-------
17
The summer season has the highest frequency of wind direction that
would carry effluents into the Park and also has the minimum average
wind speed. Both factors would lead to relatively high fluoride levels
at receptors. Because the winds tend to blow toward the Park during
daylight hours, the longer summer days, which average 15.2 hours between
sunrise and sunset, would increase the amount of time that emissions are
carried into the Park.
An effort was made to estimate the relative seasonal impact of the
aluminum plant on the Park. Dispersion calculations were performed
assuming constant fluoride emission rate and diffusion parameters for
the four seasons. Calculating on the basis of seasonal wind direction
frequency, average wind speed, and duration of sunlight, the relative
impact in summer was equated to 100; fall, 43, winter, 38; .and spring,
54. The calculations, however, did not consider the impact of accumulated
pollutants transported into the Park as a result of the local wind-
stability pattern discussed earlier. The most conducive conditions for
development of this local pattern are generally light wind flow
together with essentially "cloudless" skies. These conditions normally
are most frequent in late summer through early fall. The above treatment
suggests that the potential for damage within the Park is greatest in
summer through early fall.
REPRESENTATIVENESS OF STUDY PERIOD
Climatic records for 1970 from the Glacier National Park Airport
(Kalispell), which is 8 miles southwest of the aluminum plant, have been
compared with the 30-year mean. April 1970 in the Glacier area appears
to have been rather cool and dry with strong surface winds while the following
3 months were slightly warmer and wetter than 'normal. The fall months were
again somewhat cooler and drier than their "normal" counterparts. Since
no major deviations from the normal weather pattern occurred during
1970, the data can be considered representative of normal years. Vegeta-
tion growth may have been somewhat better than normal because of the
relatively warm, wet summer.
-------
18
SUMMARY . '
Nighttime effluents from the Kalispell-Columbia Falls region are
often confined near their source until mid-morning by the basin-like
lower section of the Flathead River Valley. Under the influence of
daytime upslope winds and the deepening convective currents, the valley
flow is entrained into the base of the upper wind pattern at some time
during the forenoon. This upper wind blows into Glacier National Park
about 47 percent of the summer days.
The highest concentration of fluorides is carried into the Park
soon after this flow is established and while the night's collection and
the current emissions are mixed in a limited layer of the upper flow. The
pattern is established between 9 a.m. and noon and may continue beyond
sunset.
During other seasons of the year, this flow is somewhat less fre-
quent and the duration is reduced. Additionally, the winds are usually
stronger so that diffusion takes place in a larger volume of air with
proportionate reduction in concentrations.
AMBIENT FLUORIDE CONCENTRATIONS
Two basic types of measurements—static and dynamic—are used to detect
atmospheric fluorides. The "static" measurements consist of exposing
chemically treated filter paper to the air in the test area. Reasonably good
correlations have been found between the amount of gaseous fluoride taken
up by "limed" filter paper and the amount of fluoride accumulated in vege-
tation during the same time interval. These inexpensive static sampling
devices can be located at a number of different sites and are useful in
delineating aerial distribution of fluoride pollution. The fluoride
"dosage" rate data provided by this method are useful indicators of poten-
tial long-term or chronic fluoride damage to vegetation.
-------
19
The "dynamic" or continuous measurements of gaseous and particulate
fluoride concentrations consist of using a sequential sampler that is
capable of separating gaseous and particulate fluorides. One requirement
for this type of measurement is the availability of electric power. Thus,
for this study, the dynamic measurements were limited to the few sites
where power was available.
STATIC MEASUREMENTS
Thirty-seven static sampling sites were established throughout the
study area and within a radius of 20 miles from the aluminum plant. These
sites were arranged so that a geographical distribution of fluoride levels
in the study area could be ascertained. Locations of these static sites
are shown in Figure 8.
The sampling devices used by NAPCA differed from the standard limed
paper in that filter paper circles were impregnated with sodium formate re-
agent while the standard limed paper uses calcium formate. The method of
exposing these devices to fluorides also differed from standard procedure.
Thw NAPCA static monitors or fluoridation plates were placed in brackets
and attached to posts, utility poles, or trees with the exposed side facing
downward. The State of Montana, however, used the standard limed paper
monitors and exposed them to louvered shelters that allowed the air in
flow over the limed paper.
At some of the NAPCA stations, more than one plate was exposed to
check reproducibility of the results. Since the NAPCA plate configuration
differed from the standard limied paper and the exposure shelter used by the
State of Montana, fluoridation rates were measured at four sites using
both types of treated papers to correlate readings given by the two
methods. The places and limed papers were exposed for monthly intervals
and returned to the laboratory for analysis.
Fluoridation rates obtained in the study area for July through
November 1970 are shown in Table 2. The values are reported in
p
nanograms of fluoride per square centimeter per day (ng/cm -day).
-------
Kalispell
Figure 8. Location of fluoridation plate exposure sites.
-------
19b
Table 2. FLUORIDATION RATES MEASURED IN GLACIER NATIONAL PARK AND SURROUNDING
AREAS USING THE PLATE METHOD
Station Number
la
2a
3a
4a
5
6
7a
8a
9a
10
11
12
13
14
15
16
17
18
19a
20a
21
22
23
24a
25a
26
27 .
28a
30a
32
33
33M
34
35
36a
37a
Fluoridation rate, ng/F/cm2-day
Minutes Maximum . Average
9
n
4
11
16
4
7
6
4
2
2
2
4
5
9
5
23
21
20
5
4
3 .
8
3
11
4
4
3
8
9
4
4
37
50
_ 0
__
13
20
10
23
32
15
14
15
10
9
9
7
10
13
19
12
83
37
48
16
10
8
18
9
26
10
8
10
8
15
6
6
41
91
V ->
—
11
14
8
15
27
9
10
9
6
5
6
4
6
9
14
9
46
27
30
9
6
5
14
6
21
7
6
6
8
12
5
5
39
71
- '9b
9b
.ouauiuii^ lu^aueu in ui near
bBased on one month's data.
Park.
-------
20
Information on the location of each site, including elevation, is contained
in the appendix.
The significance of the fluoridation measurements in assessing the
potential for fluoride contamination of the Park is best shown by
graphical display of the spacial pattern of the data. The geographical
2
distribution of the average monthly fluc-ridatlon rate in ng F/cm -day...for
each site for the 5-month period is shown in Figure 9. Such isopleths are
obtained by objective analysis of the data. "This analysis consists of
drawing lines of constant fluoride level based on the available data and
subsequently joining these lines with smooth-curved contours. There is a
significant degree of judgment involved in such construction because of the
absence of sufficient data. As expected, the values decreased rapidly as
distance from the aluminum plant increased, except in the northeast
quadrant where the influence of prevailing wind patterns (described in the
meteorological section) and higher ground elevations in the Park caused
the distribution pattern to be displaced and elongated in this direction.
Although there was no monitoring station atop Teakettle Mountain,
the results from the several stations on this mountain indicate a trend of
higher fluoride concentrations with increasing elevation. For instance,
at site 35 on Teakettle and at site 19 on Apgar Mountain where high values
of fluorides were recorded, the plates were at a higher elevation than at
any of the other sites where plates were exposed. Thus, the primary area
of high fluoridation values appears, about 1 to 2 miles northeast of the
aluminum plant on Teakettle Mountain and increases as elevation increases.
A secondary area of high fluoridation values is also apparent on the upper
slopes of Apgar Mountain, 10 miles from the plant.
The distribution of airborne fluoride depicted in Figure 9 is based on
data from the limited number of exposure sites used in this study and without
regard to the variations in elevation of these sites. As previously shown ,
the topography and diurnal .air flow patterns common to the area have a pro-
nounced effect on the transport and dispersion of fluorides emanating
from the aluminum plant. As the study progressed, examination of the pre-
-------
20a
Kalispell
'Figure 9. Distribution of measured fluoridation rates,
-------
21
liminary vegetation and v/ind data revealed several locations in or near the
Park where plates had not been placed and which probably experienced high
fluoride levels. For example, the daytime wind direction would appear to
frequently carry the plume over the Bel ton Hills region of the Park, an
area not extensively monitored. Attempts to obtain measurements in the
Belton Hills were unsuccessful when successive plates located in the area
were disturbed, most lively by wildlife /attracted by the reagent used to
treat the filter paper.
Nevertheless, it was necessary to extend the fluoride distribution
pattern derived from the measured values to include all areas of the Park
potentially subjected to high fluoride exposures. The fluoride data was
extrapolated to cover the areas where measurements were not obtained. This
modified pattern more properly reflects the channeling and impingement of
fluoride pollution especially at higher elevations in the mountainous
terrain. The extrapolated distribution pattern shown in Figure 10 is
based on the supposition that not only the southern slopes of Apgar Mountain
will be exposed to higher fluoride levels but also the upper elevations of
the Belton Hills and adjacent mountains and peaks in the Flathead Range,
the Whitefish Range, and the Swan Range which comprise the Flathead National
Forest area. This projection is substantiated by'data furnished by other
study participants on the geographical distribution of fluoride content of
sampled vegetation.
The fluoridation rates measured on the southwest slope of Apgar
Mountain are of serious concern since the values approach levels found in
the vicinity of Columbia Falls where damage to sensitive vegetation has been
frequently reported. A similar situation probably exists on the southwest
slopes of the Belton Hills.
COMPARISON OF PLATE RESULTS WITH LIMED PAPER RESULTS
The State of Montana Department of Health has adopted ambient air
2
quality standards (0.30 ygF/cm -28 day) for fluoride based on the calcii
formate (limed) paper method. Specifications for preparation, exposure.
-------
2Ta
Kalispel!
Figure 10. Extrapolated distribution of fluoridation rates
reflecting topographical and meteorological
influences.
-------
22
and analysis of the paper are included in the Montana State regulation.
Although the plate method used by NAPCA differs from the paper method used
by the State, the readings provided by the two methods can be correlated.
Limed papers were exposed in louvered shelters of the type normally
used by the state at the four stations (shown in Figure 11) at which
ambient fluoride concentrations were continuously .monitored.
Duplicate sets of limed papers were exposed for calendar month intervals
and were returned to the state laboratory for analysis. Analysis data
furnished by the state laboratory for the limed papers appear in Table 3
with the analysis of the results of the NAPCA plates exposed at the same
sites for the same period of time. Fluoridation rates obtained using both
2
methods are expressed in units of yg F/cm -28 day used by the state.
Comparing the plate and the limed paper values for the 5-month period
disclosed that the plate method consistently gave readings about one-third
higher on the average than the limed paper method. Although other
factors may contribute to the higher fluoridation values from the plates,
an explanation for the difference may be the method of exposure. The
place configuration allows the filter paper to be more openly exposed to
the atmosphere, whereas the louvered exposure shelter used by the state
may restrict air flow around the limed papers and offer less ventilation. .
Statistical analysis of the two sets of data indicates that the fluoridation
rates given by the plates should be multiplied by a factor of 0.68 to be
comparable to the state results. The fluoridation rates obtained at all
of the NAPCA stations and shown in Table 2 have been multiplied by this factor
and adjusted to a 28-day rate to obtain the monthly fluoridation rates
shown in Table 4.
These results show that the average fluoridation rates measured at
five out of the fifteen stations located in or near Glacier Park approach
or exceed the state standard. The average value for site 19 on Apgar
Mountain exceeds the standards by a factor of nearly 2. All the monthly
readings obtained during the study at this site were above the state
standard.
-------
PFIRE WEATHER
STATION
Kalispell
Figure 11. Location of continuous fluoride monitoring
stations and plant exposure shelters.
-------
22b
Table 3. COMPARISON OF FLUORIDATION RATES MEASURED BY
PLATE AND LIMED PAPER METHOD3
Sample.
Period
July
September
October
November
December
•-
Fluoridation
Station0
Number
1
2
3
4
1
2
3
4
1
2
3
4
1
2
4
25
2
4
25
Rate, yg F/cm2-28
Plate
Results
0.31
0.39
0.28
0.42
0.25
0.56
0.28
0.31
0.28
0.31
0.11
0.34
0.28
0.36
0.36
0.50
_ .. _ _
0.47
0.67
day
Limed
Paper
Results
0.23
0.22
0.25
0.45
0.17
0.23
0.11
0.24 .
0.13
0.14
0.09
0.21
0.17
0.22
0.23
. 0.42
0.26
0.38
0.62
Limed
Paper
Plate
Ratio
0.74
0.56
0.89
1.07
0.67
0.41
0.39
0.77
0.46
0.45
0.81
0.61
0.60
0.61
0.63
0.84
— — — —
0.80
0.92
aLimed paper data supplied by Montana State Health Department.
Limed papers for August were lost in transit.
CA11 of these stations are located in Glacier Park or near Park boundary.
-------
22c
Table 4. FLUORIDATION RATES MEASURED BY PLATE METHOD
AND CONVERTED TO EQUIVALENT STATE OF MONTANA
UNITS.9
Station
Number
lb
2b
3b
4b
5
6
7b
8b
9b
10
11
12
13
14
15
16
17
18
19b
20b
21
22
23
24b
•25b
26
27
28b
30b
32
33
33M
34
35
36b
37b
2
Equivalent rate, ug F/cm -day
Minimum
0.17
0.21
0.08
0.21
0.30
0.08
0.13
0.11
0.08
0.04
0.04
0.04
0.08
0.10
0.17
0.10
0.44
0.40
0.38
0.10
o.os
0.06
0.15
0.06
0.21
0.08
0.08
0.06
0.15
0.17
0.08
0.08
0.70
0.95
Maximum
0.25
0.38
0.19
0.44
0.61
0.29
0.27
0.29
0.19.
0.17
0.17
0.13
0.19
0.25
0.36
0.23
1.58
0.70
0.91
0.30
0.19
0.15
0.34
0.17
0.50
0.19
0.15
0.19
0.15
0.29
0.11
0.11
0.78
1.73
Average
0.21
0.27
0.15
0.29
0.51
0.17
0.19
0.17
0.11
0.10
0.11
0.08
0.11
0.17
0.27
0.17
0.88
0.51
0.57
0.17
0.11
0.10
0.27 .
0.11
0.40
0.13
0.11
0.11
0.15
0.23
0.10
0.10
0.74
1.35
0.17C
0.17C
a
b
c
Plate method rates from Table 2.
Stations located in or near Glacier Park.
Based on one month's data.
-------
23
Applying this criteria to the projected distribution pattern shown in
2
Figure 9 suggests that much of the area within the 20 ng F/cm -day isocon-
centration lines is subjected to long-term fluoride contamination in
excess of the state standard. This included nearly all of the higher
elevations within the realm of influence of the aluminum plant emissions.
To summarize, the static monitoring devices proved to be extremely
useful in defining areas of high fluoride concentration. The fluoridation
plate or limed paper can be readily exposed at sites in the most inacces-
sible areas of the Park and surrounding territory thus providing area
surveillance not obtainable by other measurement methods.
CONTINUOUS FLUORIDE MEASUREMENTS
Dynamic measurements of gaseous and particulate fluoride concentrations
were made at four locations from June 26 to October 23, 1970. The moni-
toring stations were located along the Park boundary from 7 to 11 miles in
a northerly direction from the aluminum plant as shown in Figure 11.
Availability of electric power and nearness to the Park were determining
factors in locating the stations.
Atmospheric samples were collected over 12-hour intervals using a
sequential sampler capable of separating gaseous and particulate
fluorides. Gaseous fluorides in the air samples were selectively
absorbed on bicarbonate-coated glass tubes. After removal of the gaseous
fluoride component, the particulate fluoride was collected on a chemically
treated filter mounted at the outlet end of the tube. The glass tubes
and filters were taken back to the laboratory for analysis. The tubes were
washed, and the "fluoride ion" electrode method for determination of
fluoride ions in aqueous solution was used to determine the gaseous
component. A standard laboratory procedure for analyzing filter paper
was used for the particulate fluorides.
An interval control timer built into the sampler enabled continuous
collection of 12-hour samples from 9 a.m. to 9 p.m. (daytime) and 9 p.m.
-------
24
to 9 a.m. (nighttime). Valid data was obtained approximately 70 percent of
the time that the samplers were operated at the various stations.
Average concentrations of gaseous and particulate fluorides measured
3
at each of the four stations and reported in yg F/m are summarized in
Table 5. Tabulations of the raw data, including frequency distributions
and other statistical information, will be included in the final report.
The average 24-hour gaseous fluoride concentrations recorded by
the four stations in or near the Park (stations 1 through 4) ranged
the
3
3
from 0.06 to 0.10 yg F/m without an appreciable difference between the
averages of each station. A maximum 24-hour concentration of 0.66 yg F/nf
(0.83 ppb)* was measured at station 2 (Blankenship) during the 4-month
period.
Gaseous concentrations made up about one-third to one-half of the
total fluoride measured at each station. The gaseous component of any
fluoride's contamination is of relatively greater interest than particulate
fluorides because of the ease in which the gaseous component is assimilated
by vegetation. Nevertheless, fluoride particulates deposited on the
surface of forage and ingested by browsing animals may contribute sub-
stantially to fluoride intake of animals.
At all but one of the stations (station 3), 12-hour gaseous fluoride
levels were nearly twice as high during the day as they were at night. The
different air flow patterns existing during the daytime and nighttime
hours as discussed earlier in the report are thought to account for the
higher concentrations of gaseous and particulate fluorides found during
the day.
A tendency toward higher maximum concentrations was observed at
stations 2 and 4. Station 2 and 4 are nearer the aluminum plant and are
more in line with the predominant air flow from the plant toward Lake
McDonald. Station 3, at which the lowest values were consistently
3
*using conversion factor of 1 part per billion = O.Syg F/m .
-------
24a
Table 5. SUMMARY OF 12-HOUR GASEOUS AND PARTICULATE FLUORIDE CONCENTRATIONS
MEASURED IN GLACIER NATIONAL PARK AND SURROUNDING AREA, JUNE 26 to
OCTOBER 23, 1970
Station/Fluoride
Component
1
GAS
PAR
2
GAS
PAR
3
GAS
PAR
4
GAS
PAR
GAS
PAR
Daytime
Maximum Average
0.34
0.84
0.65
0.73
0.16
0.51
0.48
1.12
3.65
2.70
0.09
0.18
0.12
0.22
0.06
0.12
0.14
0.27
0.48
0.79
Nighttime
Maximum Average
0.25
1.18
1.02
0.98
0.12
0.32
0.20
1.33
1.05
2.41
0.05
0.13
0.07
0.12
0.06
0.11
0.06
0.17
0.18
0.55
24-Houra
Maximum Average
0.25
0.91
0.66
0.64
0.14
0.36.
0.28
0.84
2.11
1.57
0.07
0.15
0.10
0.17
0.06
0.12
0.10
0.21
0.33
0.65
^Average of daytime and nighttime values.
bSpecial sampling station operated from August 17 to October 21, 1971 at Dehlbon
residence about 1.5 miles north of the aluminum plant.
-------
25
!
recorded, is located toward the North Fork and is evidently largely by-
passed by the plume. :
Midway through the study, sampling was discontinued at station 3 and
the air sampler was moved to a special sampling site in the vicinity of
Columbia Falls (Dehlbom) where the state was operating a continuous, auto-
matic fluoride analyzer. Data from this station, designated 17A, are in-
cluded in Table 5 to provide some indication of the range of concentration
encountered in the study area. The fluoride levels recorded at station
17A are an order of magnitude greater than the levels reported at the
stations where dynamic measurements were made in the upper Flathead
Valley. The tabulation of fluoridation rates in the appendix, however,
lists several values obtained at station 19 on Apgar Mountain which are as
high or higher than values measured at station 17. This suggests that
long-term and possibly short-term fluoride exposures at specific sites in
the Park may occasionally approach the levels encountered at station 17
located nearer the aluminum plant.
Data on fluoride levels measured during different periods of the study
are presented in Table 6. As can be noted from this data, the 24-hour
total fluorides average (gaseous and particulate) did not vary appreciably
during the different months of the study. However, gaseous fluorides
decreased while particulate fluorides increased during the course of
the study. The gaseous portion, therefore, made up less and less of the
total fluorides as the study progressed. A similar trend was exhibited by
both the nighttime and daytime measurements. Examination of monthly
fluoridation rates tabulated in the Appendix reveals a similar decline in
levels during the fall months.
As mentioned earlier, the dynamic fluoride measurements were of neces-
sity limited to the few sites where electric power was available. In
order to obtain an estimate of fluoride concentrations in other areas of
the Park, a conversion factor relating absorbed fluoride on the static
plates to atmospheric concentrations was developed. The factor was deter-
mined by comparing the static fluoridation values with the average monthly
-------
Table 6. AVERAGE FLUORIDE CONCENTRATIONS MEASURED DURING DIFFERENT PERIODS IN
GLACIER PARK AND SURROUNDING AREA, 1970
(pgF/m3)
Station
Number
Operating
Period
Daytime
Nighttime
Gas
24-Hour Sample
Participate, Gas Participate Gas Participate Total Ratio Gas Total
1
- 2
,
3
4
17A
Jul 9
to Jul 31
Aug 1
to Aug 31
Sept 1
to Oct 23
. Jun 26
to Jul 31
. Aug 1
to Aug 31
. Sept 6
to Oct 21
Jun 26
to J.ul 31
Aug 1
to Aug 11
Jun 25
to Jul 31
Aug 1
to Aug 31
Sept 1
to Oct 21
Aug 17
to Aug 31
Sect 1
to Oct 21
0.15
0.08
0.06
0.13
0.12
0.11
0.08
0.05
0.14
0.17
0.10
1.06
0.22
0.15
0.18
0.20
0.22 .
0.18
0.25
0.11
0.15
0.24
0.27
0.29
0.88
0.74
0.10
0.03
0.03
0.09
0.05
0.07
0.06
0.03
0.09
0.05
0.03
0.36
0.10
0.07
0.11
0.18
0.12
0.10
0.16
0.10
0.15
0.15
0.18
0.20
0.76
0.44
0.12
0.06
0.05
0.12
0.08
0.10
0.07
0.04
0.11
0.11
0.07
0.71
0.15
0.11
0.14
0.17
0.17
0.14
0.21
0.10
0.16
0.20
0.22
0.22
0.84
0.55
0.24
0.20
0.22
0.29
0.22
0.30
0.18
0.20
0.31
0.33
0.28
1.55
0.71
0.50
0.30
0.23
0.41
0.36
0.33
0.39
0.20
0.35
0.33
0.25
0.46
0.21
ro
en
fa
-------
26
values of gaseous fluoride concentrations measured at stations 1 through
4 using the coated-tube method. A conversion factor was selected as
2 3
follows: 1 ng F/cm -day equals 0.0064 yg F/m or 0.0082 ppb of fluori'de.
This factor is based on a limited number of observations and should be
further verified by additional field measurements.
Applying the conversion factor to the fluoridation rates presented in
Table 2 gave the equivalent 'long-term atmospheric fluoride concentrations
listed in Table 7. The geographical distribution of estimated fluoride
concentrations expressed as parts per billion and based upon the static
sampling data is shown in Figure 12.
The State of Montana has adopted an ambient air quality standard for
q
gaseous fluoride of 1.0 ppb (0.8 yg F/m ) for a 24-hour average. The
estimated distribution of gaseous fluoride concentrations shown in Figure
12 implies that long-term concentrations, even in the areas of maximum
concentrations such as Teakettle Mountain, do not consistently exceed 1
ppb fluoride despite evidence of vegetation damage in these areas.
Data presented in Table 5 show that the standard was not exceeded at
any of the stations in or near the Park during the 4-month sampling
period. At station 17A, however, the state standard was exceeded on 4
days during the 65-day period from August 17 to October 21, 1970—a
maximum 24-hour value of 2.11 yg F/m being recorded on one of the days.
During one 24-hour calendar-day period at station 2 (Blankenship), the
3
concentration averaged 0.66 yg F/m , which is close to the state standard
3 3
of 0.8 yg F/m . The highest 12-hour values for both nighttime (1.02 yg F/m )
o
and daytime (0.66 yg F/m ) at any of the four stations occurred at station
2 on September 5 and 6, respectively. The average for the 24-hour period
spanning both calendar days (from 9 a.m., September 5 to 9 a.m., September
o
6) was 00.88 yg F/m , a level exceeding the state standard.
SUMMARY
The results of static sampling show conclusively that parts of Glacier
National Park, especially higii elevations in the Apgar Mountains, are.
-------
26a
Table 7. FLUORIDATION RATES SHOWN IN TABLE 2 EXPRESSED
AS HYDROGEN FLUORIDE CONCENTRATIONS
Station
Number
la
2a
3a
4a
5
6
7a
8a
9a
10
11
12
13
14
15
16
17
18
19a
20a
21
22
23
24a
25a
26
27
28a
30a
32
33
33M
34
35
36a.
37a •
Fluoridation Rate, PPB
Minimum
0.07 .
0.09
0.03
0.09
0.13
0.03
0.06
0.05
0.03
0.02
0.02
0.02
0.03
0.04
0.07
0.04
0.19
0.17
0.16
0.04
0.03
' 0.02
0.07
0.02
0.09
0.03
0.03
0.02
0.07
0.07
0.03
0.03
0.30
0.41
Maximum
o.n
0.16
0.08
0.19
0.26
0.12
0.11
0.12
0.08
0.07
0.07
0.06
0.08
0.11
0.16
0.10
0.68
0.30
0.39
0.13
0.08
0.07
0.15
0.07
0.21
0.08
0.07
0.08
0.07
0.12
0.05
0.05
0.34
0.75
Average
0.09
0.11
0.07
0.12
0.22
0.07
0.08
0.07
0.05
0.04
0.05
0.02
0.05
0.07
0.11
0.07
0.38
0.22
0.25
0.07
0.05
0.04
0.11
0.05
0.17
0.06
0.05
0.05
0.07
0.10
0.04
0.04
0.32
0.58
0.07
0.07
Stations located in or near Glacier National Park.
3Based on one month's data.
-------
26b
Figure 12. Distribution of fluoridation rates shown in
Figure 9 expressed as hydrogen fluoride
concentrations.
-------
27
I ;
exposed to relatively high long-term levels of atmospheric fluoride.
Logical consideration of the modifying effects of geography, topography,
and meteorology strongly suggests that higher elevations elsewhere in the
Park and in the Flathead National Forest are similarly exposed to high
atmospheric fluoride pollution—the source of which is the aluminum
reduction plant at Columbia Falls.
The results of dynamic sampling show that 24-hour gaseous fluoride
concentrations measured at the four valley sites located along the Park
periphery exceeded the state ambient air quality standard in one conse-
cutive 24-hour period at the Blankenship Station during the 4-month period.
The use of electric-powered air samplers precluded similar measurements at
more remote sites at higher elevations in the Park where it is anticipated
that short-term concentrations (- 24 hours) exceed the state standard
more frequently.
The fact that daytime fluoride concentrations were generally higher
than nighttime concentrations substantiates the belief that the air flow
carrying fluoride contaminants into the Park occurs predominantly during
daylight hours. Gaseous fluoride measurement data generally showed a
trend toward lower values as the study progressed. Several possible
explanations for this trend are: (1) daylight hours were reduced 25
percent from summer to fall, (2) aluminum production may have been reduced,
(3) better fluoride controls were installed at the plant, and (4) a com-
bination of the above or other factors.
VEGETATION STUDY
In contrast to most atmospheric toxicants which cause injury after
short-term exposure, fluoride is an accumulative phytotoxicant; i.e., it
is poisonous to plants that accumulate it over a relatively long period of
time. Fluoride ions enter chemical complexes and are retained within the
structure of plant leaves or needles while many other absorbed chemical
pollutants are less stable and are broken down and disseminated through
-------
28
liquid and gaseous exchange processes. Leaves on the same plant can differ
considerably in fluoride content because leaves differ in age and exposure
time.. For an individual leaf, fluoride content usually increases with
exposure time as the season progresses.
The amount of fluoride that will produce injury to plants (the injury
threshold) is not known bu± is expected to .vary from one species to ...
another. Some sensitive plants, such as ponderosa and white pine, are
known to incur injury after prolonged exposure to low ambient concentrations
of fluorides. This is probably because of the retention of fluoride in
the needles of conifers for more than one growing season in contrast to the
hardwoods, which exhibit new foliage annually.
EXPOSURE OF SELECTED PLANT SPECIES
One method for detecting the presence and the effects of air pollutants
including the fluorides is to expose susceptible plants to the ambient
atmosphere. Thus, plant species that are known to be sensitive to fluoride
injury and conifer species that are native to Glacier National Park were
exposed to the atmosphere in special shelters under controlled growing con-
ditions from June 25 to October 21, 1970.
Small, cylinder-shaped, fiberglas greenhouses were located at three
sites v/h'ere dynamic measurements of ambient fluoride concentrations were
conducted. Stations 1, 2, and 3 (shown in Figure 11) v/ere selected for the
exposure tests because of the availability of electric power and the proximity
to the Park.
At sites 1 and 2, plant shelters of the same type were equipped with
filters to remove particulate and gaseous fluorides and were operated as
control shelters. In the control shelters, ambient air was first blown
through a series of filters before entering the shelter and then pulled
from the shelter by an exhaust blower. Unfiltered ambient air was drawn
into the other plant shelters by the air movement induced by an exhaust
blower. Fans in both the filtered and unfiltered shelters circulated air
at a rate of about 1 air-volume-change-per-minute.
-------
29
Plants selected for the study included ponderosa, Scotch, and white
pine because of the many conifers found in the study area. Other plants,
such as alfalfa, Chinese apricot, and Snow Princess gladiolus, were
selected for their sensitivity to fluoride. The sources of the different
trees were: white pine—Coeur d'Alene, Idaho; ponderosa pine—Potomac
Valley, Missoula, Montana; Scotch pine--St. Regis, Montana; and Chinese
apricot—Denver, Colorado.
The pines were 3 to 4 years old and were -grown in peat pots containing
the soil that was under the trees when they were dug up. The trees were
placed at the sites 1 to 2 weeks after bud break. The 5- to 6-year-old
apricot trees were grown in larger sized containers in the soil that was
under the trees when delivered from the nursery.
Gladiolus and alfalfa in both exposed and controlled shelters were
grown hydroponically in a vermiculite-support medium. Plastic pots con-
taining the plants were placed in shallow plastic trays to which a de-
ionized water nutrient solution was added twice a week. On a weekly
schedule, all plants were flushed with distilled water, and the trays were
cleaned to rid them of algae. Heaters were placed inside the chambers in
the latter stages of the study to keep the apricot trees and the alfalfa
from freezing.
The same plants that were grown in.shelters were also grown in garden
plots located near the shelters at sites 1, 2, and 3. A garden plot was
also established at the air sampling station near Mud Lake (site 4).
Gladiolus and alfalfa were planted in native soil at each of the garden
plots, but the trees v/ere left in their containers with the original soil.
The garden plots were watered about every other day with deionized water
and once a week with nutrient solution.
Gladiolus were harvested for analysis on September 14 as the buds
were opening after about 11 weeks of growth. Alfalfa and part of the
apricot leaves were also harvested at this time. At the end of the
16-week study, the rest of the apricot leaves and the new growth of
-------
.30
alfalfa was harvested. The pine needles were also collected at this time
and divided into 1969 and 1970 needle growth for analyses.
Samples from plants grown in the exposure shelters and the garden
plots were analyzed from the NAPCA Laboratory in Durham, North Carolina.
The unwashed plant samples were identified, sorted, oven-dried , and ground
for automated wet-chemistry .analysis usi.ng an autoanalyzer. Results are
reported in yg F/g dry weight. The control values are averages .for the
same plant species in the two control chambers.
The average fluoride accumulation in 1970 needle tissue of three
pine varieties exposed for the 16-week period at the four sites is
graphically shown in Figure 13. Plants inside the shelters appear to have
accumulated more fluoride in the needle tissue than did plants outside in
the gardens. It should be noted again, however, that none of the plant
samples were washed before analysis. Therefore, any particiculate
fluoride on the needles showed up in the results as fluoride accumulation.
Logging trucks traveling over an unpaved road generated dust that spread
over the entire area around site 3 which may have contributed to seemingly
higher fluoride accumulation inside the shelter at that site.
Plants in all the shelters were protected from frequent rains that
washed many of the particulates from the needles of the plants growing in
the gardens. Because of this, the fluoride uptake of plants grown in the
gardens is probably more representative of the accumulation in native
vegetation in the vicinity of the sites. Since the control chambers were
equipped to filter out both particulate and gaseous fluoride, the parti-
culate accumulation problem did not present itself.
Although the garden plot results for each of the pines showed an
increase in fluoride accumulation in 1970 needles over the pines grown
in the control shelters, only those at site 4 showed an appreciable accumu-
lation for all three pine varieties. Average accumulation for the three
different varieties of pines grown in the gardens at site 4 was 10.6
yg F/g while the equivalent average of control pines was 5.0 yg F/g.
The values for 1970 pine needles from garden plots at the other three
-------
30a
20.0
15.0
^oo
u.'
10.0
et
cr
o
o
5.0
STATION NO. 1
STATION NO. 2
STATION NO 3
STATION NO. 4
PLANT SHELTERS
GARDENS
CONTROL
Figure 13. Average fluoride accumulation in needle tissue of three
pine varieties exposed from June 25 to October 21, 1970,
at four locations.
-------
31
sites ranged from 6.0 to 7.7 yg F/g. Average accumulation in the pine trees
exposed in the shelters at these same three sites ranged from 11.0 to 14.8
yg F/g.
Analysis data for the 1969 and 1970 needles of white, ponderosa, and
Scotch pine appear in Table 8. The amount of fluoride accumulation in
1970 growth of each pine variety in the control shelters was approximately
5 yg F/g. The range of 6.1 to 15.5 yg F/g in the 1969 growth in the control
shelters was most likely the result of the different sources of the trees.
The fluoride concentration in the soil potted with the three pine varieties
ranged from 188 to 372 ppm. Lower fluoride values in 1969 needles of
pines in gardens than in the shelters suggests, as did 1970 needle resultss
that particulate fluoride deposited on the leaves may have added to the
analysis result.
Fluoride values in control shelters for alfalfa was 5.0 yg F/g; for
apricot leaves, 2.6 yg F/g; and for gladiolus leaf tips, 12.0 yg F/g, as
were shown in Tables 9, 10, and 11, respectively. The relatively high
fluoride content of the control gladiolus may indicate that the plants in
the control shelters were exposed to a small amount of atmospheric
fluorides. Problems were experienced with the air flow in the control
shelters during the first weeks of the exposure period. Adjustment of
inflow and outflow air corrected a slight negative pressure that may have
caused unfiltered ambient air to be drawn into the shelter early in the
study. Fluoride values obtained for alfalfa and gladiolus grown in the
garden plots were higher than values for plants grown in the exposure
shelters. The media in which the plants were grown may account for some
of the difference. Alfalfa and gladiolus plants in the garden plots could
have accumulated fluoride from the soil whereas those in the growth
chambers should not have accumulated much fluoride from the vermiculite.
Fluoride accumulation in the garden plots was from 2 to 6 times greater
than control values for alfalfa, apricot, and gladiolus. Since the apricot
trees were grown in identical soil in both the control shelters and the
gardens, any fluoride accumulation above that of the control came from •
-------
31 a
Table 8. FLUORIDE ACCUMULATION IN 1969 AND 1970 NEEDLES OF WHITE, PONDEROSA,
AND SCOTCH PINES EXPOSED FROM JUNE 25 TO OCTOBER 21, 1970
(wgF/g)
Exposure/Location
Plant shelters
Site 1
Site 2
Site 3
Garden plots
Site 1
Site 2
Site 3
Site 4
Control shelters9
White Pine
1969 1970
16.5
8.3
18.3
7.3
11.4
12.7
18.5
6.1
10.6
16.7
25.3
7.8
9.1
6.2
14.2
5.1
Scotch .pine
1969 1970
34.5
—
23.5
10.0
--
6.3
14.3
9.2
12.6
12.4
8.7
5.5
7.1
5.0
8.2
4.2
Ponderosa pine
1969 1970
36.1
39.6
46.1
19.1
14.3
16.6
19.0
15.5
9.8
10.7
10.5
7.1
6.9
6.8
9.4
5.6
aFluoride content of the plants in both control shelters.
-------
31 b
.Table 9. FLUORIDE ACCUMULATION IN ALFALFA LEAVES AND
STEMS EXPOSED IN 1970 STUDY
Exposure Location
Plant shelters
Site 1
Site 2
Site 3
Garden plots
Site 1
Site 2
Site 3
Site 4
Control plant shelters
Fluoride content, ug F/g
July 24 through
September 14
13.9
12.5
11.1
21.3
19.3
24.7
32.1
4.4
September 14 through
October 21
13.6
11.5
15.1
.
—
--
--
5.0
-------
31c
Table 10. FLUORIDE ACCUMULATION IN CHINESE APRICOT LEAVES
AND STEMS EXPOSED IN 1970 STUDY
, Exposure Location
Plant shelters
Site 1
Site 2
Site 3
Garden plots
Site 1
Site 2
Site 3
Site 4
Control plant shelters
Fluoride content, ug F/g
July 14 through
September 14
6.7
8.4
10.7
10.2
9.9
9.6
12.8
4.4
September 14 through
October 21
15.9
24.3
19.7
14. 6a
•
--
--
5.0
'Date of exposure was July 14 to September 26.
-------
32
fluoride in the air. Values for the apricot leaves were 3 to 4 times
as great in the gardens as they were in the control shelters.
Concentration values did not vary enough from site to site to show
one location accumulating appreciably more fluoride than another in the
apricot, alfalfa, or gladiolus tissue.
To summarize, the'fluoride-levels In the pines grown in the garden
plots at the end of the 16-week exposure period were only slightly higher
than levels in control pines exposed to filtered air. Only at site 4 was
there a significant accumulation in all three pine varieties.
Although fluoride concentrations in plants in the unfiltered
shelters were high, the data may be largely influenced by the fact that
particulates were not washed from the samples before analysis. In the
garden plots, possible uptake of fluorides from native soils or from
soils originally potted with some of the plants cannot be discounted and
must be considered in evaluating the data.
Although several unforeseen experimental problems compromise the
usefulness of the data, the study data do show accumulation of notable
quantities of fluorides during the 16-week period.
Moderate tip burn was observed on the sensitive apricot, and gladiolus
leaves. In the case of the apricot leaves, the 2- to 3-fold increase in
fluoride levels-could only be attributed to atmospheric fluorides.
SURVEY OF INDIGENOUS VEGETATION
Dr. I. Hindawi made two observation tours of Glacier National Park
and the surrounding area during the 1970 growing season. Indigenous
vegetation was examined for evidence of air pollution injury, and
samples were collected for chemical analysis.
The NAPCA survey was limited to general inspection of readily acces-
sible areas of the Park and of the Columbia Falls vicinity where symptoms
-------
33
of fluoride injury had been reported. The observations and the chemical
analysis performed by NAPCA were intended to supplement the more extensive,
areawide vegetation surveys conducted by the University of Montana and the
Forest Service in order to verify the diagnosis of injury symptoms and
chemical analysis results performed by the other study participants. In
reporting the observations and results of histological and chemical
analysis of injured vegetation tissue made by NAPCA, emphasis is place on
injury symptoms in specific areas of the Park that clearly indicate that
visible injury to Park flora has occurred as a result of excessive accumu-
lation of atmospheric fluorides.
Visible Injury
In several areas along the Park boundary nearest the aluminum plant,
sensitive conifers and other indigenous vegetation exhibited necrotic tip
burn and margin injury symptoms that are characteristic of fluoride
damage.
A stand of white pine at Park headquarters was observed to have traces
of tip injury on 1967 and 1968 needles. Along the periphery of the Park
toward Apgar Mountain, the tip damage was more noticeable. The 1968 needles
of ponderosa pine growing in an exposed location at the base of Apgar
Mountain near the road to the Flathead River Ranger Station showed
considerable tip burn. Douglas fir at the ranger station had severe
necrotic lesions on the 1968 and 1969 needles.
Because the visible damage on conifers in the Park does not show a
uniform pattern from area to area, location, topography, and meteorology
are probably key factors in the exposure of Park vegetation to excessive
fluorides. Although some areas along the Park boundary, more protected
because of topography, appear free of injury, noticeable burn on sensitive
conifers, particularly white and ponderosa pine, have occurred in specific
areas of the Park, some located at considerable distances within the
Park boundaries. An example of tip burn occurring deep within the Park
was noted on the 1968 needles of white pine about 6 miles north of
Lake McDonald. • '. •
-------
34 ,,.'
Conifers with burned needles were observed in other areas just out-
side the Park boundaries. A commercial planting of young ponderosa pine
near Lake Five showed definite tip burn on 1968 needles. Symptoms of
fluoride injury were also observed in the vicinity of Columbia Falls and
Teakettle Mountain. Observations made in these latter areas will be dis-
cussed in the final technical report.
As previously noted, injury symptoms on sensitive conifers was con-
fined in all cases to the older need!fcs-~l967, 1968, and 1969. Although the
1970 needles did not show injury symptoms> the observations were made
during 1970; and it is possible that after .longer exposure times, these
needles may also show visible injury. The extent and severity of burn
on older needles strongly suggests that serious and irreparable damage
would have been caused to the Park flora in future years if fluoride con-
tamination had been allowed to continue at the former level.
The potential for injury to new growth will depend largely on the
current rate of fluoride accumulation as determined by fluoride emissions
and weather conditions. Surveillance involving chemical analysis of
periodically sampled vegetation should be continued.
Histological Examination of Injured Needles
Injured needles from Park trees showing burn symptoms were examined
microscopically. A hand-sectioning technique was used to obtain tissue
sections without the distortion,, induced by killing or dehydration of the
tissue. Clear and workable sections were obtained by softening the
hard tissue in a solution composed of 20 percent glycerin5 10 percent
alcohol, and 70 percent distilled water. Thiorrine stain was used to give
""clarity and resolution to the initial stages of injury. Sections were
taken from the green, uninjured portion of the needles immediately preceding
the demarcation line between injured and uninjured tissue.
Examination of the specimens revealed that the parenchymatous tissue
of palisade and spongy cells were collapsed and some chloroplasts .had
lost their integrity. The epithelial cells of the resin canal showed '
-------
35
swelling and expansion. The vascular bundles were distorted and adja-
cent cells had collapsed.
The extensive changes that occurred in the injured needle tissue
indicated that the causative agent of the needle necrosis was chemical
in nature. These pathological changes could not have been caused by
insect infestation, disease, or winter damage.
Chemical Analysis
During the observation tours, samples were taken of vegetation showing
suspected fluoride damage and sent to the laboratory for confirmation of
injury by chemical analysis for fluoride content.
The results of these analyses appear in Table 12. The needles were
divided into two nearly equal parts for the analysis—the top (top half)
and base (bottom half) as noted in the table.
The normal expected fluoride content of whole conifer needles based
on the Forest Service and University of Montana control data generally is
less than 10 ppm. The fluoride content of many of the samples reported
in Table 12 is well in excessive of this background level of 10 ppm. In
fact, the accumulation in the top portion of the needles alone ran as
high as 141 ppm, and none of the samples were found to have only back-
ground fluoride levels if the tip and base results were added. The data
further confirm that, in the past, fluoride has accumulated in the tissue
of vegetation growing in and near the Park in sufficient quantities to
produce the observed tip necrosis.
Generally, the fluoride accumulation in 1968 needles was more than
in 1969 needles,.and 1969 needles had more accumulation than the current
1970 needles. The high fluoride content of 1968 and 1969 needle growth
may reflect the effect of being exposed to higher ambient fluoride levels
during these years in addition to the influence of the longer exposure
period.
-------
Table 12. FLUORIDE ACCUMULATION IN VEGETATION SAMPLES COLLECTED IN
OR NEAR GLACIER NATIONAL PARK (ug F/g)
Collection
date
July 16
July .16. _
July 16
July 16
October
22
October
22
October
22
October
22
Location PI
Park headquarters
Near Middle Fork
Ranger Station
Base of Apgar
Mountain near Middle
Fork Ranger Station:
6 miles north of
Lake McDonald
Park headquarters
Middle Fork Ranger
Station
Station 4 at railroad
crossing on
Blankenship Road
Station 4 at railroad
crossing on
Blankenship Road
ant Varieties
White pine
Lodgepole
Ponderosa
White pine
Bear grass
Doublas fir
Ponderosa
Lodgepole
1967 Needles
Tip Base
30.0 12.0
__
83.0 8.0
--
—
—
1968 Needles
Tip Base
37.0 13.0
63.0
69.0 5.0
19.0 8.0
141.0 32.0
72.0b -
1969 Needles
Tip Base
29.0 8.0
15.0
50.0 9.0
54.0 18.0
43. Oa
74.0 16.0
122.0 9.0
61.0 14.0
1970 Needles
Tip Base
8.0 5.0
__
10.0 4.0
__
20.0 5.0
39.0 11.0
15.0 11.0
a Entire blade of grass.
b Whole needle.
-------
36
The high fluoride content of the Bear grass (43 yg F/g) collected
at Park headquarters exceeds the state standard of 35 ppm for forage, which
was considered to be the maximum safe concentration for animal ingestion.
SUMMARY
In summary, the visible injury found on conifers in or near Glacier
National Park was comparable to burn symptoms on plants caused by hydrogen
fluorides in laboratory fumigations and those previously observed in other
areas experiencing gaseous fluoride contamination.
Microscopic examination of visibly injured needles indicated cellular
disruption of a type caused by a chemical causal agent. Results of the
analysis substantiates the conclusion that needle-tip necrosis observed
on the older needles of sensitive pines in the Park vicinity was produced
by excessive fluoride accumulation.
-------
37
REFERENCES
1. Project Outline for Survey of Airborne Fluorides in Glacier National
Park and Effects on Vegetation and Wildlife, Division of Abatement,
National Air Pollution Control Administration, Durham, North Carolina,
. July 1970.
2. Carlson, Clinton E., and Gerald'E. Dewey. Environmental Pollution
by Fluorides in Flathead National .Forest .and .Glacier National Park,
U. S. Department of Agriculture, Forest Service, Northern Region
Headquarters, Division of State and Private Forestry, Forest Insect
and Disease Branch, Missoula, Montana,.October 1971.
3. Dightman, R. A. Climate of Glacier National Park, Montana, Environ-
mental Sciences Service Administration, Helena, Montana.
4. Local Climatological Data Annual Summary with Comparative Data,
U. S. Department of Commerce, NOAA Environmental Data Service,
Washington, D. C.
5. Wanta, R. C. in Air Pollution, Vol. 15 Arthur C. Stern, Ed. s Academic
Press, New York, 1967, pp. 204.
6. Winds Aloft. 5-Year Summary for 65 Locations and Three Levels Below
3,000 meters. By Season and By Month. National Climatic Center,
Federal Building, Asheville, North Carolina, Job Number 12032.
7. Kali spell Local Climatic Data, Annual Summary with Comparative Data,
U. S. Department of Commerce, NOAA, National Climatic Center,
Asheville, North Carolina.
8. Adams, D. F. Relationship of Atmospheric Fluoride Levels and Injury
Indexes on Gladiolus and Ponderosa Pine, J. Art. Food Chem. 4:64-66,
1956.
9. Weinstein, L. H., and D. C. McCune. Field Surveys, Vegetation Sampling
and Air and Vegetation Monitoring, in Recognition of Air Pollution
Injury to Vegetation—A Pictorial Atlas, Informative Report Number
L, TR-7 Agricultural Committee, Air Pollution Control Association,
Pittsburgh, Pennsylvania, 1970, pp. G3-G4.
10. Gordon, C. C. An Interim Report on Fluoride Pollution in Glacier
National Park, Environmental Studies Laboratory, University of Montana,
Missoula, M.ntana, submitted to Park Superintendent, Glacier National
Park and NAPCA, January 1971.
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38
APPENDIX A
OBSERVATIONS AND COMMENTS RELATED TO
FLUORIDE POLLUTANTS IN GLACIER NATIONAL PARK
GENERAL COMMENTS
FIELD TRIP OBSERVATIONS
CHEMICAL ANALYSIS RESULTS
Dr. 0. C. Taylor
Consulting Horticulturist
Air Research Center
University of California at Riverside
Riverside, California
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39
APPENDIX A
OBSERVATIONS AND COMMENTS RELATED TO
FLUORIDE POLLUTANTS IN GLACIER NATIONAL PARK
GENERAL COMMENTS
Phytotoxicity of airborne gaseous fluoride is well documented in
the literature. A wide variation in sensitivity is recognized; some
species may accumulate in excess of 100 parts per million (ppm) on a dry
weight basis without displaying any symptoms of injury while other species
may develop extensive areas of dead tissue when much less fluoride is
accumulated. It is generally accepted that fluoride concentrations up to
10 ppm may be accepted as a normal occurrence and that some plants, particu-
larly those closely related to tea, may accumulate much larger amounts in
the absence of atmospheric contaminants. In a plant community such as
that found in Glacier National Park, concentrations exceeding 10 ppm in
grasses and pine needles are probably associated with atmospheric contam-
ination.
Toxicity of fluorides ingested by grazing animals has also been
thoroughly documented. The total load of fluorides including deposits
on the surface and those incorporated in the plant tissues contribute
to the fluoride deposits in the bone and teeth of grazing animals. When
critical levels are exceeded, bone and tooth structure may be altered,
sometimes to the extent that the animal is severely crippled and rendered
incapable of foraging for food. Wild herbivorous animals from the field
mouse to members of the deer family depend upon their ability to flee
from their predators for survival. Even slight crippling as a result of
excessive fluoride ingestion could conceivably inhibit movement to the
extent that a species of animal would no longer be competitive in a
specified polluted area.
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40
Fluoride emissions from aluminum reduction operations, such as the
plant presently operating near Columbia Falls, Montana, about 6 miles
south of the West Glacier entrance to Glacier National Park, have at
times threatened plant and animal life in many communities throughout
the world. Local acceptance of pollution control techniques have varied
considerably for several reasons. Economic significance of the polluter
compared to other activities in a community is often a prime considera-
tion.
SURVEY OF GLACIER NATIONAL PARK AREA
In July 1970 vegetation in the Park and around Columbia Falls was
examined for evidence of fluoride-type markings. Following the survey,
details of observations at specific locations were included in a report
submitted to the National Air Pollution Control Administration. Fluoride-
type symptoms, particularly on white pine (Pinus Monticula) and ponderosa
pine (P. Ponderosa) were found to be widely distributed around Columbia
Falls and at locations extending north from the juncture of the North Fork
and Middle Fork of the Flathead River to beyond the north shore of Lake
McDonald. Similar symptoms were observed on needles of larch growing at
the juncture of the North and Middle Forks. The needle tip necrosis
symptom on pine was found exclusively on needles produced during the
1968 season. Samples of some of these needles, analyzed by the Willard-
Winter method in the laboratory at Riverside, California, contained
almost 70 ppm fluoride. No visible.injury was observed on 1969 or very
young 1970 needles, and none of this tissue was analyzed by the Riverside
laboratory.
Most"of the July 1970 survey was made in the company of Dr. Clarence
Gordon and/or his associates from the University of Montana who were
making a detailed study of possible fluoride encroachment into the Park.
Observations were made at several stations previously selected by
Dr. Gordon's group for systematic sampling of the area and at several
randomly selected areas between the north shore of Lake McDonald and
Teakettle Mountain, where we observed severe foliage injury on Pinus
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41
i
Contorta and other native species in that area. The fluoride-type symptoms
were very severe on the south slope of the mountain but diminished greatly
in severity below the crest on the north slope although some evidence of
fluoride injury extended well down the slope towards the valley floor.
EVALUATION OF PROJECT REPORTS
Interim reports prepared by Dr. Gordon from the University of Montana
and by Mr. Clinton Carlson and Mr. Jerald Dewey for the USDA Forest
Service provide a great deal of data to indicate that excessive levels of
fluoride were continuing to accumulate in vegetation growing within
Glacier Park. It is not clear whether irreversible damage or economic
loss has occurred, but the data presented make it clear that pollutants
originating at the Anaconda Aluminum Reduction Plant have accumulated
regularly during the past several years.
In Dr. Gordon's report it was pointed out that during the summer of
1970 the prevailing winds were from the southwesterly direction between
10 a.m. and 5 p.m. With this information it is not surprising that the
highest fluoride levels were found in vegetation at the 3500- to 4200-foot
level. As solar radiation heated the south slope of Teakettle Mountain,
the emissions from the aluminum plant would be expected to rise; and
after clearing the mountaintop, would be carried in a northeasterly
direction. There would be some downward mixing of the gases, but the
highest concentrations would probably remain elevated until the face of
the next mountain was intercepted.
Gaseous fluoride enters leaf tissue through stomatal openings and
is excluded when stomata are tightly closed. Surface adsorption may occur,
but significant tissue injury or significant increase in fluoride content
of tissue is dependent on absorption of hydrogen fluoride through open
stomata. Stomata, being light sensitive, are open widest during midday
when the greatest photosynthetic activity is taking place. This midday
period (10 a.m. to 5 p.m.) is precisely the period when the prevailing
southwesterly winds would move fluoride-polluted air into Glacier National
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42
Park. Accumulation of fluorides in the Lake McDonald area, eastern Apgar
area, and southwestern Bel ton Hills winter range area is not surprising.
There is no doubt that fluorides emitted by the aluminum plant are
entering Glacier National Park and these fluorides are being accumulated
by plants and several species of animals, but the consequences cannot be
readily assessed. Certainly there is a threat that fluoride-contaminated
air from the industrial source could cause alterations in the plant and
animal community in a limited region northeast from the West Glacier
entrance.
FIELD TRIP OBSERVATIONS
COLUMBIA FALLS AND VICINITY
Severe needle tip necrosis was observed on ponderosa pine (P. Ponderosa)
at three locations within Columbia Falls. The injury was confined to
needles on the growth produced in 1968 while the 1969 needles and immature
current season needles were apparently free of injury. The brown
necrotic tip of 1968 needles was about 2 to 3 centimeters long on trees
in the area. Each necrotic tip had from 2 to 4 dark brown bands and a
sharp line of demarcation between health and necrotic tissue. This symptom
is characteristic of injury produced on sensitive pines by fluorides in
the polluted atmosphere.
Young pine trees in the ornamental plantings at the entrance to the
Columbia Falls Forest Ranger Station had considerable injury on the 1968
needles and a smaller amount of injury on the 1969 needles. No injury
was observed on 1970 needles. The oldest leaves on a young birch tree
growing in the same area were severely injured. Necrosis at the margin
of these leaves extended between the principal veins almost to the mid-rib.
Younger leaves on the same shoots had intercostal and marginal chlorotic
symptoms. The injury symptoms were of the type that may be associated
with accumulation of fluorides.
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43
Ponderosa trees at various points along the high from Columbia Falls
south to Bigfork were examined for air pollution symptoms. Tip necrosis
was observed on needles for at least 10 miles southeast of Columbia Falls.
A large commercial planting of conifers about 20 miles from Columbia Falls
appeared to be free of injury.
TEAKETTLE MOUNTAIN
Young lodgepole pine and other shrubs at the top of Teakettle Mountain
and on the south slope above the aluminum reduction plant were severely
marked with necrotic lesions. Many of the young pine trees were heavily
defoliated and partially or entirely dead. The needle tip necrosis ranged
from red-brown to light brown with numerous dark brown bands. Typical
fluoride-type symptoms were also found on trees at the top of the
mountain.
The 1968 needles on Douglas fir trees were heavily marked with heavy
fleck-like chlorotic lesions and a general golden-brown discoloration.
Needles produced more recently were free of this symptom. Wild strawberry
leaves had marginal necrosis and dark purple pigmentation between the
major veins extending toward the mid-rib. Bear grass was severely injured
with light tan colored necrosis on the top 10 inches or more of mature
leaves.
NORTH SLOPE OF TEAKETTLE MOUNTAIN
Tip necrosis was observed in 1968 needles on white pine trees scattered
along the north slope of the mountain, but the 1969 and 1970 needles
appeared to be free of injury. The symptoms were particularly severe on
a few trees at the base of the mountain on Wright's Ranch.
A young planting of ponderosa pine near Lake Five was heavily
marked with necrotic tips (3 and 4 centimeters long) on 1968 growth;
more recent growth had no apparent symptoms. Similar symptoms were also
observed on lodgepole pine (P. Contorta) along the roadside in the same
area.
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44
GLACIER PARK '
' • • "' " " T -i
Iris grov/ing wild at the site of an old homestead had necrotic damage
on leaf tips. Necrosis' on some of the oldest leaves was 6 inches or more
in length. There was also some tip burn on 1969 needles on a young
Douglas fir at this location.
About 0.3 miles south of the McDonald Creek bridge at the base of
Apgar Mountain, mature ponderosa pine trees had considerable tip burn on
1968 needles. The burn was more severe on needles sticking upward than
on those hanging downward from the shoots. The necrotic tip was 2 to
3 centimeters long and had 3 to 5 dark brown bands. The 1969 needles on
many shoots were considerably shorter than 1968 needles.
White pine trees at Glacier National Park Headquarters had necrotic
tip burn on 1968 needles and some burn on 1967 needles. The burn was
about 2 inches long and was much more severe on the lower 30 to 40 feet of
the two trees examined. Branches in the top of the trees appeared to
have very little injury.
White pine trees at the Lake McDonald ranger station and on the
Hheeler property west of the station were marked with top burn on 1968
needles. Necrotic tips were 1.5 to 2 centimeters long.
Tip burn was observed on white pine about 6 miles north of the north
shore of Lake McDonald. The trees were growing on a ledge approximately
500 feet above the highway on the east side of the stream. Necrosis was
found only on the tip of 1968 needles.
SUMMARY
Necrotic tip burn on ponderosa pine and necrosis of some leaves on
broad leaf plants were observed near the aluminum reduction plant and
in Columbia Falls. These symptoms appeared to be identical to the symptoms
characterized as fluoride type. Similar symptoms were observed for several
miles southeast of the plant on 1968 needles. The symptom expressions
-------
45
suggest that vegetation in the vicinity of Columbia Falls was exposed to
high fluoride concentrations in 1968 and perhaps early in 1969. Since that
time, injury appears to be light and is probably confined to a radius of
a few miles around the plant. Heaviest injury is apparent on the south
slope of Teakettle Mountain.
Needle burn on 1968 needles of sensitive pine species in Glacier
National Park indicates that an excessive fumigation with fluorides pro-
bably occurred in 1968 but tissue analyses should be used to confirm
this observation. Observations from the top of Teakettle Mountain confirm
that fluoride-type symptoms are prevalent to the top of the mountain.
Wind movement from the south-southwest would obviously carry any pollutants
reaching the top of the mountain up the middle fork of Flathead River into
the Lake McDonald area. During the visit to the Park> there was ample
evidence that smoke from the plant did enter the Park along the Middle
Fork River and McDonald Creek.
Tissue analyses should be relied upon to indicate if excessive amounts
of fluoride are accumulated by foliage and if injury can be expected in
the future. Mo evidence of recent foliage injury was observed within
the Park. However, this is not to say that chronic symptoms of fluoride
accumulation may be manifested at a later date as the newer growth is
exposed to low ambient levels of the pollutant over an extended period of
time. A continued program of sampling and analysis of vegetation to ob-
tain a time profile of fluoride uptake would provide useful data on the
potential impact of present fluoride emissions from the Anaconda aluminum
plant.
CHEMICAL ANALYSIS RESULTS
Fluoride content of pine needles collected at four locations in
Glacier National Park was sufficiently high to indicate that the observed
tip necrosis on 1968 needles was a result of fluoride accumulation. The
analyses obtained by the Willard-Winter method were as follows:
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46
Sample
Ponderosa Pine (Montana University Station)
White Pine (Park Headquarters)
White Pine (North Shore of Lake McDonald)
White Pine (6 Miles North of Lake McDonald)
Fluoride
Needle Base
(PPM)
Needle
Tip
8
4
16
4
69
29
12
48
Needles from 1968 growth on sample trees were cut into two approximately
equal lengths and the tip. and base sections were-analyzed separately.
The top sections contained both necrotic and green tissue. Samples were
dried for 48 hours at 45° C in a forced-draft oven and were ground to
pass a 40-mesh screen.
A sample of injured birch leaves collected in front of the Columbia
Falls Ranger Station contained 49 ppm fluoride. Although this level of
fluorides is sufficient to produce the observed necrosis, some of the
injury may have been due to high chloride concentrations that were also
detected in the tissue. It is assumed that the chloride came from the soil
and may have contributed to the injury.
Results of the analyses substantiate the conclusions that needle tip
necrosis observed on 1968 growth of ponderosa and western white pine in
the vicinity of Lake McDonald was produced by fluoride accumulation.
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47
APPENDIX B
TABLE B-l
LOCATION AND ELEVATION OF
FLUORIDATION NET WORK SITES
TABLE B-2
MONTHLY FLUORIDATION RATE
MEASUREMENT RESULTS
-------
TABLE B-l. LOCATION AND ELEVATION OF FLUORIDATION NETWORK SITES
Site
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
30
32
33
33
34
35
36
37
Elevation above
mean sea level ,
feet ;
3150
3100
3200
3250
3040
3000
3145
3145
3800
3350
3500 :
2993
2900
3250
3400
3320
3100
3050
5200
3150
3580
4200
3150
3400
3280
3400
3260
3145
• 3400
3070
3050
3050
3920
4200
3400
3250
Location
Glacier Park; near Fire Weather Station
Blankenship Ranch
Rose Ranch
Near railroad and Blankenship Road
crossing
DeMerritt Property
Northeast of Whitefish
Upper Lake McDonald; at Ranger Station
Lower Lake McDonald; near Apgar
Camas Creek Road; on trail to Huckeberry
Mountain
North Fork Road; near Big Creek Ranger
Station
North Fork Road; 5 miles north of station
Northwest end of Lake Blaine
South of Creston; along Highway 35
Highway 2; 2 miles south of Park
headquarters
East side of Teakettle Mountain
North Ford Road; near Turnbull Creek
turnoff
Dehlbom property
Badrock Canyon
Apgar Lookout
Park headquarters
Vicinity of Hungry Horse Dam
Emery Hill
Co ram
Boehm's Bear Den
Base of Apgar ridge
Red Eagle; near Nyack
Kootenai Creek; east of West Glacier
Southeast side of Lake McDonald
Hill above Park headquarters
North of Morning Slough Lake
South of Morning Slough Lake
• Southeast of Morning Slough Lake
Teakettle Mountain; 3 miles north of
Relay Tower
Teakettle Mountain, 1.5 miles north of
Relay Tower
Hill near gravel pit, on Highway 2
Hill above Park headquarters; 150 feet
feet below site 30
-------
laole B-2.
MONTHLY FLUORIDATION RATE MEASUREMENT RESULTS
Flupridation rate, ng F/cm^-day
. Site
Number
la .
2a
3a ::
4a . •
5
6
7a
8a
9a :
10
11
12
13
14 :
15
16
17
18,
19a .
20a
21
22
23
24a
25a
26
27;,
28S
30a
32
33
33M
34
35
36,
37a
July
nb
14b
10b
15b.
29
15
14 .
15 .
10
9
9 .
7
10 •
13
17
12
38
23
20
13
10
8
13
9
24
10
6
10
_ _
--
_ _
--
—
__
__
August .
13b :
1^-
• iob:
23b
30 ; :
10b:
9
8 :
5
5 :
8 :
—
--
12 :
19 :
12 .
83b
30b
29
16
4b
h
5D
18b
8
24b
b
7°
7b
6
_ —
b
15°
6b
b
6
37
__
__
September
9b
20b
10b :
nb :;
32
7b ;:
8
7
4
4
3
3
4
9
b
14°
K
6D :
43b
21b
48
8
5b
L
5
13b
5
26b
b
6°
6b
5
_ _
b
9
5b
b
5
41
50b
__
October
i
10bl
llb
4b
12b
16
4b
7
6
4
2
2
2
4
5
b
9°
K
5D
43b
25b
22
5
4b
h
3B
8b
3
llb
b
4°
4b
3
8
10
4b
b
4
—
?ib
__
November
10b
13b
6b
13b
— .
IB. M
«. •.
8
—
-._
—
—
—
6
b
10°
--
23b
37b
5
— —
..
16b
18b
--
8b
8b
--
_ ^ .
--
—
_ _
9
9
Average
Monthly
Rate
11
14
8
15
27
9
10
9
6
5
6
4
6
9
14
-' 9
46
27
30
9
6
5
14
6
21
7
6
6
8
12
5
5
39
71
9
9
a Exposure sites located in or near Glacier Park
b Value is average of two or more duplicate readings
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48
APPENDIX C
TABLE C-l
METEOROLOGICAL DATA APPLICABLE TO THE
GLACIER PARK REGION
-------
Table Cl. METEOROLOGICAL DATA APPLICABLE TO GLACIER NATIONAL PARK REGION.
ON APPROXIMATELY 30 YEARS OF RECORDS
Temperature, °F
NORMALS, MEANS, AND EXTREMES BASED
Elevation
(Feet MSL)
and
Station
2965
Kali spell
3154 West
Glacier
3690
Polebridge
5213
Maria Pass
Kali spell
W. Glacier
Polebridge
Marias Pass
Kali spell
W. Glacier
Polebridge
Maria Pass
Kali spell
W. Glacier
Polebridge
Marias Pass
Kali spell
W. Glacier
Polebridge
Marias Pass
-ca-i — —— , .. .... t .-•— i
Mean
Maximum
57
54
53
45
84
80
81
73
56
53
55
49
28
28
28
23
55
53
54
47
Daily
Minimum
31
30
25
23
48
47
41
40
32
33
27
29
12
14
7
7
31
31
25
25
Extremes of
Record
Highest Lowest
81
80
86
' 74
104
98
101
93
81
79
85
82
50
49
51
48
105
98
101
96
Apri 1
14
3
-12
-30
July
32
32
27
26
October
15
15
-7
January
-26
-37
-46
-55
Annual
-35
-37
-46
-55
Mean No. of Days
that temperature
remained 1 32°
Maximum Minimum
0
a
a
3
0
0
0
0
0
a
a
2
17
18
19 .
23
52
53
56
94
20
21
26
26
a
a
2
4
21
16
23
21
30
30
30
31
195
192
238
247
Precipitation
All.
Forms
Mean
1.
2.
1.
2.
1.
1.
1.
1.
1.
2.
1.
3.
1.
2.
2.
4.
15.
29.
22.
38.
04
00
55
93
04
48
18
35
24
57
84
14
37
99
63
17
42
11
32
29
, inches
Snow and Sleet
Maximum in
Mean one month
2.4
4.5
4.1
25.5
0.0
Tb
1.1
2.0
3.1
11.9
20.0
36.6
32.8
44.0
67.3
134.2
119.6
251.3
' 8
24
24
87
0
9
28
16
61
34
74
91
123
.1
.0
.8
.0
.0
0
_ _ - .
.9
.0
.5
.0
.8
.5
.2
.0 -
49.7
74.5
91.2
123.0
CO
ess than Yd. hours.
Trace
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