LENA VALLEY, 110HTANA,
AREA ENVIRONMENTAL POLLUTION STUDY
SUMMARY
Environmental Protection Agency
Washington, D.C.
June 1971
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U. S. ENVIRONMENTAL PROTECTION AGENCY
*t,.y-'
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HELENA VALLEY,
, AREA
POLLUTION STUDY
ENVIRONMENTAL PROTECTION AGENCY
Washington, D. C.
June 1971
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PREFACE
The Helena Valley, Montana, Area Environmental Pollution Study was
a cooperative undertaking between the Federal Government and the State
of Montana.
Because it had been alleged that pollutants are contributing to the
endangerment of health and welfare in the Helena Valley, this study was
undertaken to provide factual information bearing on the allegations and
to aid in delineating the solution of any observed problem.
The investigation concerned contamination of the environment by
arsenic, cadmium, lead, zinc, and sulfur dioxide from the industrial
smelting complex in the city of East Helena.
Since the atmosphere was suspected as being the major pollutant-
transport mechanism in the area's environment, the National Air Pollution
Control Administration* was designated to lead and coordinate Federal
participation in the study.
The study included the investigation of in-plant air quality
and lead accumulation in smelter workers. However, since right-of-entry
to the plants was gained under Montana State law, which prohibits pub-
lication or public release of any information gathered during in-plant
surveys, such material is not included in this report. Results were
furnished to the Montana State Department of Health for such use as it
may deem appropriate.
For the purpose of the Helena Valley, Montana, Area Environmental
Pollution Study, the findings of the many individual investigations are
integrated and summarized in this report. The remainder of the report,
to be published as a companion document, provides baseline data and guidance
for future research activities.
*Presently the Office of Air Programs of the Environmental Protection Agency.
Ill
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ACKNOWLEDGMENTS
Mr. Benjamin F. Wake, Director, Division of Air Pollution,
State Department of Health, and Mr. Earl V. Porter, Director,
Region VIII, Office of Air Programs, Environmental Protection
Agency, served as the respective State and Federal Co-Directors
of the study.
Mr. Norman A. Huey, Assistant Director, Region VIII, Office of
Air Programs, Environmental Protection Agency, was principal technical
coordinator and editor for the study.
Mr. William H. Megonnell, Compliance Officer, Office of Air
Programs, Environmental Protection Agency, assisted with the over-
all study direction and report preparation.
This document has been compiled from technical reports con-
tributed by authors affiliated with the Environmental Protection
Agency, Food and Drug Administration, University of Montana, and
the U.S. Geological Survey. Principal authors are: Mr. Francis M.
Alpiser, Mr. Marius J. Gedgaudas, Dr. C. C. Gordon, Dr. Douglas I.
Hammer, Dr. Ibrahim J. Hindawi, Mr. Norman A. Huey, Mr. Paul A.
Humphrey, Dr. Trent R. Lewis, Mr. A. T. Miesch, Dr. Samuel I. Shibko,
and Mr. Albert V. Soukup.
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CONTENTS
RESULTS AND RECOMMENDATIONS .' 1
INTRODUCTION 3
BACKGROUND INFORMATION 7
History 7
Topography. 7
Climatology 8
Population Statistics 9
Employment 9
Industry 9
Agricultural Activity 10
Property Evaluation 10
REVIEW OF PREVIOUS POLLUTION STUDIES 11
A Study of Air Pollution in Montana, July 1961 to July 1962 .. 11
A Study of Air Pollution in the Helena - East Helena
Area, October 1965 to October 1968 11
Pollution Study in East Helena, December 1968 12
ENVIRONMENTAL EVALUATION 13
SULFUR DIOXIDE 13
Annual Mean Concentrations 13
Daily Concentrations 14
Hourly Concentrations 14
Maximum Concentrations 15
ARSENIC 15
Contamination of Air 16
Contamination of Water 16
Contamination of Soil 16
CADMIUM 17
Contamination of Air 17
Contamination of Water 18
Contamination of Soil • • I8
LEAD i 19
Contamination of Air 19
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Contamination of Water 20
Contamination of Soil 20
ZINC 21.
Contamination of Air 21
Contamination of Water 21
Contamination of Soil 22
EVALUATION OF POLLUTANT EFFECTS 23
VEGETATION 23
Damage from Sulfur Dioxide 23
Arsenic Contamination 23
Cadmium Contamination 24
Lead Contamination 24
Zinc Contamination 24
ANIMALS 24
Acute Effects on Health 25
Heavy-Metal Accumulation In Hair 25
Heavy-Metal Accumulation in Organs 25
Heavy-Metal Accumulation in Animal Foodstuffs 26
HUMANS . 26
Heavy-Metal Accumulation in Hair 26
Body Burden 26
POLLUTANT SOURCES 29
SULFUR DIOXIDE EMISSIONS 30
Lead Smelter 31
Zinc Recovery Plant 32
Source-Receptor Relationships 32
PARTICULATE EMISSIONS 33
LEAD SMELTER 33
Zinc Recovery Plant 34
Source-Receptor Relationships 34
WASTE WATER EMISSIONS 34
Lead Smelter 34
Zinc Oxide Plant 35
SOLID WASTE DISPOSAL 35
Lead Smelter 35
Z1nc Oxide Plant 35
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HELENA VALLEY, MONTANA, AREA
ENVIRONMENTAL POLLUTION STUDY
RESULTS AND RECOMMENDATIONS
Atmospheric concentrations of sulfur dioxide in the Helena
Valley exceed Montana air quality standards and levels reported in
Federal criteria to be associated with deleterious effects on human
health, vegetation, and materials. Industrial operations of American
Smelting and Refining Company and Anaconda Company in East Helena
are the responsible sources.
Air, water, and soil in the Valley are contaminated with heavy
metals from the East Helena smelting complex. Water in Prickly
Pear Creek is contaminated by the American Smelting and Refining
Company plant. Arsenic, cadmium, and lead, which are emitted as
air pollutants from both plants, settle and accumulate in soil
and on vegetation to an extent surpassing levels that are toxic to
grazing farm animals. Furthermore, evidence indicates that sub-
clinical effects could be occurring in humans.
Threshold-limit values have been established for industrial
exposure of healthy adults for 8 hours per day, 40 hours per week,
during a normal working life; knowledge is insufficient, however,
to establish limits below which heavy metals may be considered harm-
less to humans in various states of health who are exposed to heavy
metal contamination from birth or, through parental contact with
heavy metals in the environment, even before birth. Calculations
of total body burden of lead and cadmium from air, food, and drink,
plus evidence of heavy-metal accumulation in human hair, are
sufficient cause for concern and action to control pollution
from the smelting complex in East Helena.
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Heavy-metal particulates are not prone to significant dispersion,
and tall stacks will not change the impact of these particles on the
Helena Valley. Increasing the height of emissions is not emission
control, in that it removes no pollution; tall stacks merely spread
gaseous pollutants and fine particles for wider consumption.
Industrial sources should abate emissions to the lowest practicable
levels by application of modern technology.
Residents of Helena Valley should be informed of possible toxic
effects from consumption of vegetables or other food items that might
be contaminated either from the soil or from dustfall. All locally
grown vegetables should be washed to remove surface contamination
before consumption.
Ranchers within about 5 miles of the smelting complex should
be advfsed of the danger to low-grazing farm animals like horses and
sheep. Such animals should not graze in fields 1n the vicinity of
East Helena.
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INTRODUCTION
In 1888 the Helena & Livingston lead smelter was built at East
Helena. The American Smelting and Refining Company purchased this
operation in 1899. Anaconda Company, in 1927, built a plant adjacent
to the lead smelter to recover zinc from the latter's waste slag.
In 1955 The American Chemet Corporation constructed a nearby paint
pigment plant whose raw material is zinc oxide from the Anaconda zinc
plant.
As early as 1901, the American Smelting and Refining Company
began protecting itself against claims for damages to the neighboring
premises with indentures releasing them from such claims.
Lead contamination of the soil has been acknowledged by the
management of American Smelting and Refining Company, as stated by
this quotation from a 1963 letter sent to a neighboring rancher
by the plant manager:
I have finally received the results of the soil samples
and must report that your soil is highly contaminated with
lead. Following are comments on the samples:
Under some circumstances, it is risky to pasture horses
op land, the surface portions of the soil of which contain
oVer 200 parts per million of lead. This risk is great
when grass is grown in soil with a content of 1000 ppm
lead. During the times the grass is lush and the animals
can graze in the pasture without cropping low, or without
picking up some soil, I should say the danger would be
minimized.
I cannot imagine a very luxuriant growth of vegetation
in a pasture which contains such high concentrations of
metals unless the soil is quite calcareous. Certainly, in
this particular area, it would not be "up to the stirrups"
of an ordinary size horse. My advice, therefore, is that
you discour§ge the use of this pasture for animals, especially
for horses.
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Contamination of the air with sulfur dioxide also was acknow-
ledged by letter from management to a neighboring rancher:
During the spring of 1967 and the spring and summer
of 1968, your property south of the smelter has experienced
considerable exposure to S02. Under the present state of
knowledge, it is not likely that the condition can be im-
proved for a matter of years.
Because of this unfortunate situation, it would appear
advantageous to all concerned if you were to move out of that
location. Possibly you can find another location in the
countryside and your house could be moved there.
Please let me know if you are interested so that we can
negotiate terms of sale.
An allegation of heavy-metal contamination of garden vegetables
was brought to the attention of the Food and Drug Administration's
Regional Inspector in Helena on September 20, 1968. This information
was relayed from the Food and Drug Administration to the Consumer
Protection and Environmental Health Service. Discussions between
Montana Health Officials and Consumer Protection and Environmental
Health Service led to an environmental pollution study of the Helena
Valley, Montana, area.
In May 1969, the Memorandum of Agreement on the following page
was signed by Federal and state officials.
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MEMORANDUM OF AGREEMENT
BETWEEN
THE MONTANA STATE DEPARTMENT OF HEALTH
AND
THE NATIONAL AIR POLLUTION CONTROL ADMINISTRATION
THE FOOD AND DRUG ADMINISTRATION
THE ENVIRONMENTAL CONTROL ADMINISTRATION
(CONSUMER PROTECTION AND ENVIRONMENTAL HEALTH SERVICE,
PUBLIC HEALTH SERVICE,
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE)
Authority; Under provisions of Section 301 of the Public Health
Service Act, as amended (Public Law 78-410), and Section 103 (a)
(3) of the Clean Air Act, as amended {Public Law 90-148), the
National Air Pollution Control Administration, the Food and Drug
Administration, and the Environmental Control Administration of
the Consumer Protection and Environmental Health Service, Public
Health Service, U. S. Department of Health, Education, and Welfare,
and the Montana State Department of Health agree to cooperate in
the conduct of a study of environmental pollution as enumerated
in the terms of this memorandum.
Title of Project: Helena Valley, Montana, Area Environmental
Pollution Study.
Purpose of Project; To conduct a study of the types, amounts,
sources, distribution and effects of environmental pollution in the
Helena Valley, Montana area, with a view to recommending solutions
of any problems that are found.
Need for Project:' It has been alleged that pollutants arising from
man's activities in the area are contributing to health and welfare
endangerment. This study will provide factual information bearing
on the allegations and aid in delineating solution of any observed
problem.
Location of Project: Helena Valley, Montana; specific geographical
boundaries to be determined during field work.
Direction of the Study: Administrative co-direction of the study
shall be the responsibility of Mr. Benjamin F. Wake for the State
of Montana, and Mr. Earl V. Porter for the Federal government.
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Arrangements for and coordination of participation by State and
Federal agencies not parties to this agreement shall be the respon-
sibility of the respective co-directors. Technical direction of
each party's personnel shall be by the designee of each individual
agency.
Duration of Federal Participation: Approximately six months' field
work, plus such time as necessary for data analysis and report
'preparation, unless extension of the study is agreed to by the
parties concerned.
Sharing of Data: Data gathered during the study, because of its
possible research value, shall be freely accessible to all partici-
pating agencies. However, data especially created by the activities
of this study, prior to submittal of the final report, shall be
released only after consultation with the Montana State Department
of Health.
Final Report: A report of findings and recommendations will be
prepared by the Federal participants, in consultation with the Montana
State Department of Health, Any of the parties to this agreement
may disseminate copies of the final report in accordance with their
regulations and normal procedures.
Special Provisions; Details concerning conduct of various
phases of the study and the roles of individual agency participants
will be developed jointly by the Federal and State parties to this
agreement and will be appended, as developed, to become parts of
this agreement.
Investigations for this study were conducted between July 1969
and July 1970.
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BACKGROUND INFORMATION
History
In 1864, four prospectors in the hostile reaches of Montana
Territory came upon a gulch that they considered to be their "last
chance" in their search for gold. Gold was found in such abundance
that a city sprang into existence. Within 1 year this mining
community numbered over 100 cabins and was known as "Last Chance."
The main street, running north and south through the center of town,
became "Last Chance Gulch."
In 1882, shortly after the coming of the railroads, Helena became
a corporate city with over 600 citizens voting for a charter.
With the enormous loads of gold being mined in the area, Helena
was fast becoming the banking capital of the territory. The city
soon enjoyed the reputation of being the wealthiest city per capita
in the world.
When Montana Territory was created by Congress in May 1864,
the city of Bannock was the seat of the territory legislature. In 1865,
the capital was moved to Virginia City, another booming miners' town 200
miles to the south of Helena. By 1875 Helena was the uncontested center
of wealth and culture in the Montana Territory. Shortly thereafter
Helena became the capital city.
Prickly Pear Junction, a "way station" on the stage coach route
from Ft. Benton to Helena and other gold camps, became East Helena
with the building of a lead smelter in 1888. In 1899, the American
Smelting and Refining Company purchased the old Helena & Livingston
plant. In 1927, the Anaconda Company installed a zinc plant, and
other industries that use smelter by-products settled in the vicinity.
Topography
The Helena Valley in western Montana is an intermountajn valley
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bounded on the north and east by the Big Belt Mountains and on the
west and south by the main chain of the Continental Divide. The
valley is approximately 25 miles in width from north to south, and
35 miles long from east to west. The average height of surrounding
mountains above the valley floor (elevation 3700 feet) is about 3000
feet.
The city of Helena, with an average elevation of 4100 feet, is
located on a slope at the south side of the valley. The southern
parts of the city have elevations of about 4300 feet, and the northern
parts are at elevations of about 3800 feet.
The city of East Helena is located about 4 miles east of Helena
at an elevation of about 3900 feet. The ground slope is much less
evident in East Helena than it is in Helena. The ground south of
East Helena, where the smelting operations are located, is 30 to 50
feet higher than the city.
The valley floor continues to slope gently to the north and
northeast to Lake Helena, which is located about 10 miles northeast
of East Helena. Lake Helena is the lowest point in the valley with
an elevation of 3650 feet.
Climatology
The climate of the Helena Valley may be described as modified
continental.
As may be expected in a northern latitude, cold waves may
occur from November through February, with temperatures occasionally
dropping well below zero. Summertime temperatures are moderate, with
maximum readings generally under 90° F and very seldom reaching 100°.
Total precipitation varies widely throughout the valley, from a
semiarid total of 9 to 10 inches in the drier northern and eastern
portions of the valley, to a subhumid 30 inches along the Continental
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Divide to the southwest. Most of the precipitation falls from April
through July from frequent showers or thundershowers, with some Steady
rains in June, the wettest month of the year. Late summer, fall, and
winter months are relatively dry. Snow can be expected from September
through May. During the winter months snow may remain on the ground
for several weeks at a time. Amounts during the spring and fall are
usually light.
Strong and persistent temperature inversions are common to the
Helena Valley. The surrounding mountains shelter the area from the
winds. At night, cold air drains into the valley from the surrounding
mountain slopes.
Population Statistics
Population statistics for the Helena Valley can be estimated
from Helena and East Helena statistics. There are 125 farms in the
valley. These people may not be included in the city statistics.
Table 1 gives population estimates for Helena and East Helena.
Table 1. ESTIMATED POPULATION OF HELENA AND EAST HELENA
Year Helena East Helena
1950 17,581 1,216
1960 20,227 1,490
1969 26.602 2.079
Employment
The largest employer in the Helena Valley is the State of Montana.
Helena is the state capital. Retail trade and professional services
make the greatest remaining contribution to employment.
Industry
Heavy industrial manufacturing companies have located within the
city of East Helena. American Smelting and Refining Company operates
a custom lead smelter that employs 180 workers. Anaconda Company
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operates a zinc recovery plant that employs 80 workers. American
Chemet manufactures paint pigments and employs 10 people. Several
miles southwest of the city of East Helena, the Kaiser Cement and
Gypsum Company operates a cement plant that employs 75 workers.
About 20 light industrial manufacturing companies* in the city of
Helena employ about 400 people.
Agricultural Activity
There are approximately 220,000 acres of agricultural land on
the valley floor, valued at about $10 million.
Most farming in the valley is by dry-land practices. The soil
is seeded 1 year, left fallow the next, and seeded again the third
year. A total of 20,000 acres of wheat and barley is planted each year.
The yearly gross income is estimated to be $300,000 and $200,000 from
wheat and barley, respectively. Four thousand acres of alfalfa is
grown on irrigated land with the estimated worth being about $2 million.
Two hundred acres is planted in either corn, oats, or potatoes, with
an approximate value of $9,000. Three thousand acres is used as
seeded or improved pasture, and about 200,000 acres is used as range-
land pasture.
About 700 private gardens are planted in the valley to produce
tomatoes, beets, carrots, corn, beans, peas, onions, radishes, and
cabbage.
There are 15,000 cows and calves in the valley; their market value
1s $3 million. Also present are 5,000 sheep and lambs, 5,000 chickens,
1,000 hogs, and 800 horses, the combined worth of which is estimated
at more than $300,000.
Property Evaluation
Value of properties within the Helena Valley can be estimated
from the biennial reports of the State Board of Equalization for
Lewis and Clark County.
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Table 2. HELENA VALLEY PROPERTY EVALUATION
(dollars)
Lewis and Clark County
Assessed valuation
Personal property
All real estate, including
improvements, town lots
Agricultural lands and
improvements
Grazing lands
All livestock
All timber
June 30, 1960
80,000,000
30,000,000
40,000,000
6,000,000
3.000,000
2,000,000
70,000
June 30, 1968
100,000,000
30,000,000
60,000,000
7,000,000
3,000,000
3,000,000
80,000
REVIEW OF PREVIOUS POLLUTION STUDIES
A Study of Air Pollution in Montana, July 1961 to July 1962
There was a study of air pollution conducted by the Montana State
Board of Health from July 1961 to July 1962 with assistance from the
Division of Air Pollution, Public Health Service, U.S. Department of
Health, Education, and Welfare. Limited air quality measurements were
made in seven Montana cities.
Total suspended particulate loadings in the city of Helena were
reported to average 72 micrograms per cubic meter (ug/m^) of air.
Arsenic, lead, and fluoride were reported to average 0.08, 0.34,
and 0.10 ug/m » respectively.
A Study of Air Pollution in the Helena - East Helena Area,
October 1965 to October 1968
Another study of air pollution,from October 1965 to October 1968,
was conducted by the Montana State Department of Health. The objective
was to define the quantity and quality of certain air pollutants in the
Helena - East Helena area.
Monthly average sulfur dioxide (SOg) concentrations up to 0.055 part
per million (ppm), hourly averages up to 0.4 ppm, and 5-minute average
concentrations up to 6 ppm were reported. Suspended particXilate loadings
averaged 76 pg/m3 in East Helena and 50 to 60 pg/m3 at various sampling
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locations in Helena. Arsenic and lead concentrations were higher in East
Helena than in Helena. The contribution of the smelter complex in East
Helena to air pollution was demonstrated by the decline in sulfation,
dustfall, and lead content of dustfall during a smelter strike.
The study recommendations called for reduction in sulfur dioxide
and dust emissions from the East Helena smelting complex, prohibition
of open burning, and elimination of street dust through paving.
Pollution Study in East Helena, December 1968
In December 1968, a study of pollution in East Helena, financed by
the Montana State Board of Health, was conducted by Dr. C. C. Gordon,
Associate Professor of Botany, University of Montana, Missoula, Montana.
The study objective was to determine the severity and extent of sulfur
dioxide damage to vegetation. The study scope was extended to include an
Investigation of the effects of lead and cadmium on the ecosystem.
Dr. Gordon reported that local farmers had stated that raising of
horses had not been feasible for several decades. American Smelting
and Refining Company plant management reportedly has been of the opinion
that residents of East Helena should not eat local garden vegetables
because of metal contamination.
Sulfur dioxide effects were found on pine seedlings as far as
4 miles south of the East Helena smelter complex. Elevated lead
and cadmium levels were reported in garden vegetables and in animal
tissues.
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ENVIRONMENTAL EVALUATION
A1r, water, and soil were examined for contamination by arsenic,
cadmium, lead, and zinc. In addition, airborne sulfur dioxide was
measured.
SULFUR DIOXIDE
Sample averaging time is important in the evaluation of sulfur
dioxide pollution of the air. Unlike generalized air quality deterio*-
ration from myriad emission sources in urban areas, a single source
or a few sources in close proximity will cause a heterogeneous pollutant
distribution usually characterized by infrequent but severe levels.
The Helena Valley is subjected to this type of pollutant distribution,
as demonstrated by the range in annual, daily, hourly, and 1-minute
average sulfur dioxide concentrations.
Annual Mean Concentrations
The Environmental Protection Agency's Office of Air Program's
best judgment of effects that occur when various levels of pollution are
reached is reported in AP-50. Air Quality Criteria for Sulfur
Oxides. This document states that:
1. At concentrations of 0.04 ppm, frequency of lung disease
may increase and mortality from bronchitis and lung cancer
may occur.
2. At concentrations of 0.03 ppm, chronic plant injury and
excessive leaf drop may occur.
3. At concentrations of 0.12 ppm, the corrosion rate of steel
may increase by 50 percent.
The Montana State Board of Health adopted 0.02 ppm sulfur dioxide
maximum annual average as a state-wide ambient air quality standard
on May 27, 1967.
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The city of Helena experienced 0.01 ppm from June 1969 to June
1970. Residents of East Helena were exposed to 0.0] to 0.08 ppm,
depending upon their location within the city. Throughout most of
East Helena, levels varied between 0.02 to 0.04 ppm, but a small
center-city portion was exposed to levels between 0.04 and 0.08 ppm.
A 20-square-mile area adjacent to and southeast of the city of East
Helena had levels greater than 0.02 but less than 0.04 ppm. The
remainder of the Helena Valley was not exposed to levels greater than
the State standard of 0.02 ppm.
Daily Concentrations
Air Quality Criteria for Sulfur Oxides states that:
1. At concentrations of 0.1 ppm, absenteeism from work and
.increased hospital admissions of older persons for
respiratory disease may occur.
2. At concentrations of 0.2 to 0.3 ppm, patients with chronic
lung disease may experience accentuations of symptoms, and
the general population may experience increased mortality.
Montana's state-wide sulfur dioxide standard is 0.10 ppm, 24-
hour average, not to be exceeded over 1 percent of the days in any
3-month period.
The concentration equaled or exceeded 0.1 ppm on 4 of the 129
days sampled (3 percent) in Helena, on 5 of the 128 days sampled
(4 percent) in East Helena, on 15 of the 136 days sampled (11 percent)
in the Helena Valley 0.5 mile southeast of the smelter, and on 10 of
the 123 days sampled (8 percent) in the Helena Valley 2.5 miles
southeast of the smelter.
Concentrations equaled or exceeded 0.2 ppm on 4 days 0.5 mile
southeast of the smelter and on 1 day at 2.5 miles southeast.
Hourly Concentrations
Air Quality Criteria for Sulfur Oxides reveals that at concentration?
of 0.10 ppm sulfur dioxide, in the presence of particulates, visibility
may be reduced to about 5 miles.
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Montana's standard is 0.25 ppm, not to be exceeded more than 1
hour in any 4 consecutive days. In approximately 140 days of sampling
1n the summer of 1969, 0.25 ppm was exceeded during 41 hours in Helena,
47 hours in East Helena, 126 hours in the Helena Valley 0.5 mile
southeast of the smelter complex, and 74 hours in the Helena Valley
2.5 miles southeast of the smelter complex.
Maximum Concentrations
While the effects of short-term peak concentrations are not
discussed in the Air Quality Criteria Document and although limits
are not included in the Montana State standards, at concentrations
greater than 1 ppm the air usually is so fouled as to cause nausea and
coughing in the normal population. The taste threshold occurs at
0.3 ppm.
The instruments used during the 140-day sampling period to measure
sulfur dioxide had an upper limit of detection of 4 ppm. The monitor
located in Helena registered greater than 1 but less than 2 ppm for 48
minutes. The monitor in the city of East Helena registered greater
than 2 but less than 4 ppm for a total of 41 minutes. In the Valley
0.5 mile southeast of the smelter, a monitor registered greater than
4 ppm for about 2 minutes.
ARSENIC
Arsenic compounds are toxic to humans, animals, and plants.
Most arsenic compounds, when heated in air, are converted to arsenic
trioxide, a tasteless, toxic, white powder. Arsenical dusts can
produce dermatitis, bronchitis, and irritation to the upper respira-
tory tract. Ingestion of arsenic can produce keratosis and cancer
of the skin. The relationship of arsenic to other types of cancer,
particularly lung tumors, is strongly suggestive. Herbivorous animals
have been poisoned from eating plants contaminated with arsenic. Seventy
milligrams of arsenic trioxide has been reported as a fatal dose for
man.
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Contamination of Air
Maximum permissible atmospheric concentrations have not been
adopted in the United States. A 24-hour standard of 3 pg/m has
been recommended in the U.S.S.R. and Czechoslovakia.
During the summer and fall of 1969, an average 24-hour concentra-
tion of 0.005 yg/m3 was found in Helena. Maximum 24-hour concentrations
did not exceed 0.07 yg/m3. East Helena was exposed to an average of
0.08, although the maximum reached 0.3 pg/m3. These values represent
the highest found in the Helena Valley.
The concentration of arsenic in the particulates that settle
in the vicinity of the East Helena smelter is 200 to 1000 ppm. Each
month, 1 to 4 milligrams (mg) of arsenic settle on each square meter
of surface area within a 1-mile radius of the smelter.
Contamination of Water
Arsenic concentrations of 2 to 4 mg per liter are reported not
to interfere with the self-purification of streams. The Montana
water quality criteria are consistent with the Public Health Service
Drinking Water Standards that state that the concentration of arsenic
in drinking water should not exceed 0.01 mg per liter and concen-
trations in excess of 0.05 mg per liter are grounds for rejection of
the supply.
Sampling of waters in the Helena Valley revealed arsenic in the
surface waters in Prickly Pear Creek, downstream from the smelting
complex. On October 25, 1969, and on April 4, 1970, the surface water
in Prickly Pear Creek, which is 2.5 miles northwest of East Helena,
contained 0.01 mg per liter. On the same dates, Missouri River water
at the Helena City Water Plant intake contained 0.02 mg per liter.
Contamination of Soil
The arsenic content of soils ranges from 1 to 50 ppm and averages
about 5 ppm. The soil outside, but adjacent to, the Helena Valley
contains 6 ppm.
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The concentrations of arsenic in the soil decrease with distance
from the smelting complex. At distances of 1 and 2 miles, respectively,
the upper inch of uncultivated soil contains 140 and 23 ppm and the
upper 4-inch layer of cultivated soil contains 40 and 20 ppm.
CADMIUM
Cadmium is recognized as an element with high toxic potential.
Children have been made sick by consuming a frozen dessert containing
13 to 15 mg of cadmium per liter.
Cadmium is absorbed without regard to the level of existing body
concentrations, which indicates a lack of homeostatic mechanisms for
the control of cadmium levels. It has been reported that the feeding
of 0.1 mg of cadmium per liter causes accumulation of cadmium in the
liver and kidney tissues of rats.
Epidemiological evidence associating cadmium with renal arterial
hypertension in humans is conflicting.
Contamination of Air
When inhaled, cadmium can produce pulmonary emphysema and bron-
chitis, kidney damage resulting in proteinuria, and gastric and intes-
tinal disorders. In one epidemiological study, air cadmium levels
have been associated with cardiovascular mortality rates, but this
relationship is very tenuous and has not been confirmed in other studies
to date.
Maximum permissible atmospheric concentrations for cadmium have
not been suggested or adopted in the United States. In 1963, the
National Air Sampling Network reported that the nation's air contained
an average 24-hour concentration of 0.002
The maximum reported individual annual concentration was 0.028
vg/m3. A maximum 24-hour concentration of 0.18 vg/m3 was reported in
East St. Louis, Illinois.
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During the summer and fall of 1969, the city of Helena was
exposed to an average 24-hour concentration of 0.03 and a maximum
24-hour concentration of 0.11 ug/m3. The residents of East Helena,
depending upon their location within the city, were exposed to an
average 24-hour concentration between 0.06 and 0.29 ug/m3 and to a
maximum 24-hour concentration of 0.7
The concentration of cadmium in the particulate matter that
settles in the vicinity of the East Helena smelter is 200 to 1000 ppm.
Each month, 1 to 4 rog of cadmium settles on each square meter of surface
area within a 1-mile radius of the smelter.
Contamination of Water
Recognition of the toxic potential of cadmium when it is taken by
mouth is based on the occurrence of poisoning from cadmium-contaminated
food and beverages, epidemiologic evidence that cadmium may be asso-
ciated with renal arterial hypertension, and long-term oral toxicity
studies in animals.
According to the Public Health Service Drinking Water Standards,
a drinking water supply containing in excess of 0.01 mg cadmium per
liter should be rejected.
Water was sampled from Prickly Pear Creek (downstream of the
smelting complex) on July 1, 1969; October 25, 1969; and April 4,
1970. The cadmium content was 0.006, 0.001, and 0.007 mg per liter,
respectively. Limited sampling of other Helena Valley waters suggests
that the concentration of cadmium generally is less than 0.001 mg
per liter.
Contamination of Soil
The expected cadmium content of soils is 0.5 ppm. The concen-
tration in the soil outside, but adjacent to, the Helena Valley ranged
from less than 0.5 to 2 ppm.
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The concentration of cadmium in the soil of the Helena Valley
decreases with distance from the smelter. At a distance of 1 , 2, and
4 miles, respectively, the upper inch of uncultivated soil contains 68,
17, and 4 ppm and the upper 4-inch layer of cultivated soil contains
21, 9, and 3 ppm.
LEAD
Lead can be seriously injurious to health as a result of accumu-
lations in the body. Long-term daily intake of less than 0.6 mg
by healthy adults may cause small increases in body burden, but no
clinical disease. An intake in excess of 0.6 mg per day may result
in the accumulation daring a lifetime of a dangerous quantity of lead
In the body.
Contamination of Air
Because maximum permissible atmospheric concentrations have not
been established in the United States, judgment regarding the .
significance of lead contamination must be related to permissible
body burden. Intake from the air can be approximated by assuming 20
percent retention of what is inhaled and a daily intake of 20 cubic
meters of air.
During the summer and fall of 1969, the city of Helena was ex-
posed to an average daily concentration of 0.1 yg/m , with maximum
daily concentrations up to 0.7 pg/m3. The residents of East Helena,
depending upon location within the city, were exposed to an average
daily concentration of 0.4 to 4 yg/m3, with maximum daily exposures
up to 15
Daily respiratory intake in Helena is calculated to be 0.5 micro-
gram (yg). In East Helena, the daily respiratory intake varies from
2 to 20 yg, depending upon location within the city.
Particles that settle from the air in the vicinity of the smelter
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contain 6,000 to 28,000 ppm. Ingestion of 0.007 to 0.04 ounce of
these participates may exceed the daily body-burden limit.
Within a 1-mile radius of the East Helena smelter, 30 to 140 mg
of lead settles in particulate form each month on each square meter of
surface area. Accordingly, each 0.5 to 2 square feet of surface area
is contaminated each month by an amount equivalent to the daily body-
burden limit for lead.
Contamination of Water
The lead concentration in drinking water supplies ranges from
traces to 0.04 mg per liter, averaging 0.01 mg per liter. At con-
centrations of 0.1 mg per liter, bacterial decomposition of organic
matter is inhibited and some fish are susceptible to lead poisoning.
Adults consume 1 to 3 liters of drinking water per day.
The Public Health Service Drinking Water Standards state that
0.05 mg of lead per liter constitutes grounds for rejection of the
water supply.
Helena Valley waters contain less than 0.001 to 0.04 mg per liter.
The water in Prickly Pear Creek contained 0.044, 0.000, and 0.042 on July
1, 1969, October 25, 1969, and April 4, 1970, respectively. Missouri
River water at the Helena City Water Plant intake contained 0.033, 0.000,
and 0.019 on those respective dates.
Contamination of Soil
The expected lead content of soil is 16 ppm. The concentration
in soil outside, but adjacent to, the Helena Valley is 15 ppm. The
concentration in the soil of the Helena Valley decreases with distance
from the smelting complex. At distances of 1, 2, and 4 miles, respec-
tively, the upper inch of uncultivated soil contains 4000, 600, and
100 ppm and the upper 4-inch layer of cultivated soil contains 700,
250, and 90 ppm.
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ZINC
Zinc is a normal constituent of the human body. It is taken
Into the body in the diet or by inhalation, and is eliminated by
processes of excretion and perspiration. Excessive body intake,
however, can result in zinc poisoning.
Contamination of Air
Inhalation of zinc does not represent a significant health risk to
the general population, but it is of concern in the field of occupational
health. Exposure to air containing milligram quantities per cubic
meter has resulted in metal-fume fever, a malaria-like illness that
lasts about 24 hours and has never been known to be fatal.
Maximum permissible atmospheric concentrations for zinc have not
been established. The 1967 American Conference of Governmental Industrial
Hygienists adopted the value of 5 milligrams per cubic meter (mg/m ) for
zinc oxide fumes in occupational exposures.
During the summer and fall of 1969, airborne zinc in the Helena
Valley, depending upon location, averaged less than 0.1 to 3 ug/m ,
with maximum 24-hour values up to 8 yg/m3.
Contamination of Water
Zinc salts act as gastrointestinal irritants. Although the
Illness may be acute, it is transitory. The emetic concentration in
water is 1 gram per liter. Communities have used waters containing
up to 27 mg per liter without harmful effects.
Concentrations of about 30 mg per liter impart a milky appearance
and a metallic taste. Concentrations below 4 mg per liter generally
are not detectable by the human sense of taste.
Inasmuch as zinc in water does not cause serious effects on health
but produces undesirable esthetic effects, it is recommended that con-
centrations of zinc be kept below 5 mg per liter.
21
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Water supplies within the Helena Valley were found to contain
0.003 to 0.2 mg per liter.
Contamination of Soil
The expected content of the soil is 44 ppm. The concentration
in soil outside, but adjacent to, the Helena Valley is 58 ppm. The
concentration of zinc in the soil of the Helena Valley decreases
with distance from the smelting complex. At a distance of 1 mile,
the upper inch of uncultivated soil and the upper 4-inch layer of
cultivated soil contain 1100 and 300 ppm, respectively, whereas at a
distance of 2 miles from the complex both soils contain 200 ppm.
22
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EVALUATION OF POLLUTANT EFFECTS
VEGETATION
Leaf damage and contamination can be attributed to specific pollutants
Suppression of growth rate may occur as a result of pollution. From
studies conducted during the surmer of 1969, it was concluded that the
vegetation growth rate was suppressed 15 percent in the vicinity of the
city of East Helena.
Damage from Sulfur Dioxide
Within 1 mile of the smelter complex, sulfur dioxide leaf damage to
Indigenous alfalfa, corn, sweet potato, lettuce, tomato, grape, apple,
and plum occurred during the summer of 1969.
Sulfur dioxide damage was identified historically on pine trees
growing within 1/2 mile of the smelter complex during 1969. In 1968,
this type of damage was found at distances up to 4 miles from the
smelter complex.
•Arsenic Contamination
The tolerance for arsenic on sprayed fruits and vegetables set by
the Food and Drug Administration is 3.5 ppm. Lettuce, carrot, beet,
pinto bean, and alfalfa grown in the city of Helena in 1969 had an
average arsenic content of 0.4 ppm.
Concentrations in edible portions of unwashed vegetables and crops
grown in 1969 within a 4-mile radius of East Helena varied from 0.05
to 14 ppm on a wet basis. Pasture grass, barley straw, and alfalfa
contained 0.4 to 14 ppm. Barley, wheat, and oat kernels contained 0.05
to 0.9 ppm. Onion, lettuce, carrot, and cabbage had maximum concentra-
tions of 0.9 to 3 ppm. Apple, beet, kohlrabi, potato, radish, rutabaga,
string bean, and garden peas had maximum concentrations of 0.05 to 0.5
ppm.
-23
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Cadmium Contamination
Lettuce, carrot, beet, bean, and alfalfa grown in the city of Helena
during 1969 had an average cadmium content of 0.7 ppm.
The concentration in edible portions of unwashed vegetables and
crops grown in 1969 within a 4-mile radius of East Helena varied from
0.05 to 10 ppm. Pasture grass, alfalfa, and barley straw contained
0.1 to 10 ppm. Barley, wheat, and oat kernels contained 0.1 to 1.5 ppm.
Lettuce and beet maximum concentrations were 3.4 and 2.5 ppm, respectively.
Lead Contamination
Lettuce, carrot, beet, bean, and alfalfa grown in the city of Helena
during 1969 had an average lead content of 1 ppm.
Concentrations in edible portions of unwashed vegetables and crops
grown in 1969 within a 4-mile radius of East Helena varied from 0.1 to
100 ppm. Pasture grass, barley straw, and alfalfa contained 1.4 to 100
ppm. Barley, wheat, and oat kernels contained 0.1 to 10 ppm. Lettuce,
beets, and cabbage had maximum concentrations of 17, 15, and 9 ppm,
respectively.
Zinc Contamination
Lettuce, carrot, beet, bean, and alfalfa grown in the city of Helena
in 1969 had an average zinc content of 12 ppm.
Concentrations in edible portions of •unwashed vegetables and crops
grown in 1969 within a 4-mile radius of East Helena varied from 0.5 to
230 ppm. Pasture grass, barley straw, and alfalfa contained 23 to 124
ppm. Barley, wheat, and oat kernels contained 23 to 86 ppm. Beet,
lettuce, carrot, and garden peas had maximum concentrations of 68, 36,
36, and 22 ppm, respectively.
ANIMALS
Systematic investigation of health abnormalities caused by air
pollutants was not feasible during this study. Accumulation of heavy
metals in hair, in organs, and in edible animal tissue was investigated.
2*
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Acute Effects on Health
Horses are more susceptible than other species of farm animals to
the environmental toxicants that occur within the Helena Valley. The
1969 post-mortem report on a 3-year-old bay mare reads:
10/12 - about 4 pm on horse reported to have clinical signs of
"smoked" horse syndrome. Frothy nasal exudata, congestion and
consolidation in lungs with varying degrees of hepatization,
grossly; not the severity of lung damage as seen in some previous
cases on ranch. All other systems (no nervous exam) appeared
grossly normal.
This report is consistent with chronic lead and/or cadmium exposure,
pneumonia primary or secondary to heavy-metal exposure, and/or heart
disease primary or secondary to heavy-metal exposure. The presence of
toxic levels in the kidney (300 ppm cadmium and 3 ppm lead) and in the
liver (80 ppm cadmium and 4 ppm lead) but not in the mane, indicates
an acute rather than a long-term or chronic exposure.
Heavy-Metal Accumulation in Hair
Hair is a depot for arsenic, cadmium, and lead during long-term
exposure to these metallic toxicants. Increasing levels of arsenic,
cadmium, and lead in the manes of horses of the Helena Valley correlate
with proximity to the smelter complex. Older horses, horses residing in
the Valley for the longest duration, and chronically impaired horses
have the highest concentrations of lead and cadmium. A significant
percentage of the horses exhibit lead and cadmium levels that are two
to five times the usual concentrations of cadmium and lead in horse
mane hair.
Heavy-Metal Accumulation in Organs
Livers and kidneys of uncaged domestic rabbits living within
0.5 mile of the smelter complex contained elevated levels of cadmium
and lead. Cadmium content of the livers from different rabbits varied
from 4 to 9 ppm, and content of the kidneys varied from 20 to 60 ppm;
the usual cadmium content is approximately 0.1 ppm for liver and 0.3
ppm for kidney. Lead content of the livers varied from 3 to 8 ppm, and
content of the kidneys varied from 2 to 19 ppm; the usual lead content
is less than 0.1 ppm.
25"
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Liver and kidney tissues of mice living in the Helena Valley also
contain increased levels of cadmium and lead. The average cadmium
content of liver tissue varied from 0.4 to 5 ppm, and the content of
kidney tissue ranged from 1.5 to 14 ppm. Liver and kidney tissue of
similar animals caught outside, but adjacent to, tbe Valley averaged
0.2 and 2 ppm cadmium, respectively. Jn liver tissue, the average
lead content varied from 2 to 15 ppra and in kidney tissue, from 2 to
110 ppm. Liver and kidney tissue of similar animals caught outside,
but adjacent to, the Valley both averaged 0.5 ppm leaoU
Heavy-Metal Accumulation in Animal Foodstuffs
Delayed opening of a local slaughterhouse limited the evaluation
of the hazard of foodstuffs derived from the animal population to
samples that could be collected from local farms. Beef, swine, chicken,
and rabbit muscle within 2 miles of the smelting complex contained
maximum concentrations of 0.6 ppm arsenic, 0.4 ppm cadmium, 0.5 ppm
lead, and 70 ppm zinc. Whole milk was found to contain a trace quantity
of arsenic, 0.02 ppm of cadmium, 0.06 ppm of lead, and 5 ppm of zinc.
HUMANS
Investigation of air-pollution-related health impairment in the
residents of the Helena Valley was not within the scope of this study.
Investigations were made, however, of heavy-metal accumulation in human
hair and body burdens of heavy metals.
Heavy-Metal Accumulation in Hair
The exposure of the residents of the Helena Valley to heavy metals
was reflected by elevated concentrations of arsenic, cadmium, and lead
in the hair of fourth-grade school boys. Elevated levels of these
metals in hair have not been associated with any clinical illness in
these children.
Average and maximum heavy-metal levels in hair are listed by city
in Table 3.
Body Burden
Acceptable daily intake of trace metals is based upon analysis of
common foodstuffs, air, and water and upon excretions. Estimated
2$
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Table 3. HEAVY-METAL LEVELS IN HAIR FOR THREE CITIES
East Helena
Helena
Bozemana
Arsenic
Average
5.2
0.8
0.4
Maximum
30
1
1
Cadmi urn
Average
2.0
1.3
0.9
Maximum
6
6
3
Lead
Average
43
12
8
Maximum
175
75
22
aBozeman, a neighboring city not believed to be influenced by contamina-
tion, is listed for the sake of comparison.
maximum daily intake levels for arsenic, cadimum, lead, and zinc are 0.9,
0.2, 0.4, and 13.0 milligrams, respectively.
The diet represents the major source of body intake of these heavy
metals; however, in areas of high contamination, ingestion of soil or dirt
also may be a consideration. In East Helena, ingestion of 10 milligrams
(0.0004 ounce) of the airborne settleable particulates will double the
acceptable daily intake of lead. The ingestion of 200 milligrams of such
particulate matter will result in an intake of cadmium that is double the
acceptable level.
Assuming that garden vegetables contain heavy-metal contaminants
equivalent to the maximum measured and that garden vegetables provide the
entire dietary source of vegetables on a continuing basis, calculations
Indicate that the body burden will be exceeded for cadmium and lead.
Tissue accumulation is to be expected. Although no acute health
hazard is indicated, concern must be given to the effects that might occur
following continuous exposure to these levels of cadmium and lead.
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POLLUTANT SOURCES
Annually, industrial processes in the Helena Valley are the source
of approximately 80,000 tons of sulfur dioxide and 6,000 tons of partic-
ulate matter. Additional particulates are also emitted from unpaved
roads.
Industries of the East Helena smelting complex contribute the bulk
of air pollution found in the Helena Valley. This complex consists of
the lead smelter of the American Smelting and Refining Company, the zinc
oxide plant of the Anaconda Company, and the paint pigment plant of the
American Chemet Corporation.
The East Helena smelter of the American Smelting and Refining
Company converts mineral ore to usable metal. Lead concentrates and
crude ore are brought to the plant by rail. Ore concentrates contain
50 to 70 percent lead and 10 to 30 percent sulfur. Gondola cars (about
8 per day) are unloaded with a backhoe onto moving belts that carry
the material up to receiving bins. Crude ore is put through a crusher
before being put into a bin. Concentrates are mixed with zinc residues,
limestone, and siliceous ore; the material is pellitized and then
delivered by belt conveyor to the sintering plant, where the mixture is
fused by burning off the sulfur. The resulting sintered ore concentrate
1s mixed with coke and charged into the top of a blast furnace. The
charge, about 1,000 tons of material per day, 1s ignited, melted, and
reacted to form lead bullion and slag. Lead and slag flow from the
furnace continuously into a brick-lined settler. Slag overflows the
settler into slag pots and is transferred by rail either to the Anaconda
Zinc Oxide plant or to the slag pile. Lead bullion is tapped into pots
and transferred by rail to the dressing plant. In the dressing plant,
the lead is poured into one of several large (90-ton) kettles and allowed
to cool. Copper, having a higher melting temperature, crusts or drosses.
The dross floats on top and is skimmed off; after being mixed with soda
ash and coke breeze, the dross is transferred to a reverber»atory furnace
where it is smelted for further separation of zinc and lead according to
29
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density. Molten lead flows to the bottom and a layer of slag floats to
the top. Just under the slag, copper matte (metal sulfides) forms, and
copper speiss (metal arsenides and antimonides) settles just over the
molten lead. The matte and speiss are cooled and shipped out of the
area to a copper recovery plant. Molten lead is recycled to the dressing
kettles. Lead in the dressing kettle is further purified by the addition
of sulfur and by cooling, which results in further removal of copper as
matte. The lead is then cast into 10-ton ingots and shipped out of the
area to a lead refinery.
The zinc oxide plant of the Anaconda Company recovers zinc from the
lead smelter slag. Daily, 100 tons of zinc oxide is recovered from
approximately 500 tons of smelter slag. Molten slag received directly
from the lead smelter or from cold storage is transported by rail in
large pots and dumped into the top of a furnace. Pulverized coal and
air forced into the bottom of the slag bath heat the mixture to 2,200° F.
Zinc is vaporized, oxidized, and drawn from the furnace through a flue-
and-cooling system, where the oxides solidify. The air stream bearing
the solid oxides is forced through a baghouse that collects the zinc
oxide. Molten slag, drawn from the bottom of the furnace into pots, is
taken by rail and dumped on the waste slag pile.
The paint pigment plant of the American Chemet Company modifies
zinc and copper oxides. Daily, 15 tons of zinc oxide from the zinc
fuming plant is heated with natural gas in rotary kilns to improve the
whiteness quality by removing traces of coal and by reacting any remain-
ing sulfur. This product is then pulverized and packed in bags for
outside distribution. Additionally, up to 100 tons per day of zinc oxide
from a different source can be pulverized. This plant also has the
capacity to produce 150 tons per day of cupric oxide pigments. Crude
cupHc oxide is reduced in a closed retort, milled, and packaged for
distribution.
SULFUR DIOXIDE EMISSIONS
The East Helena lead smelter and zinc recovery plants collectively
account for 99 percent of the Helena Valley sulfur dioxide emissions.
30
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Lead Smelter
During the normal production rate of 1,200 tons of feed per day,
the smelter emits 330 tons of sulfur dioxide. The charge stock contains
up to 30 percent sulfur, of which 89 percent is released during the
sintering operation, 4 percent is released from the blast furnace, and
7 percent remains with the slag. Small amounts are released from the
slag dump, the dressing plant, and the reverberatory furnace. Off-gases
from the sintering operation pass through an electrostatic precipitator
for dust removal and are discharged to the atmosphere from a 400-foot
stack. Off-gases from the blast and reverberatory furnaces are combined,
pass through a baghouse, and are discharged into the atmosphere at an
elevation of 117 feet.
No attempt is made to curtail emissions by either recovery or
removal of sulfur from the gaseous emissions. In July 1970, the Montana
State Board of Health adopted an emission standard stating that within
3 years the amount of sulfur that may be released into the atmosphere in
gaseous form must be less than 10 percent of the amount contained in
the process raw material.
The 400-foot stack is used to reduce the impact of emissions from
the sintering operation at ground level near the smelter. In the spring
of 1970, an induced draft fan and stack heater were added to reduce such
impact further. Three ground-level suTfur dioxide monitoring stations
are operated In the smelter area by the American Smelting and Refining
Company. Reportedly, if a monitor detects a concentration of 0.7 ppra
that persists for 15 minutes, the sintering plant is shut down and is
not started up until the monitor indicates a concentration of less than
0.5 ppm for 15 minutes.
Sulfur dioxide emissions from the sintering operation can be reduced
by conversion to and recovery as sulfuric acid, by conversion to and
recovery as sulfur, or through removal by scrubbing. Sulfur dioxide
emissions from the baghouse can be reduced by a limestone scrubber.
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Zinc Recovery Plant
Operating at a production rate of 100 tons of product per day, the
plant emits 13 tons of sulfur dioxide. The raw material is 2 percent
sulfur, and the resulting waste slag is 1 percent sulfur. Sulfur
dioxide is emitted from the charging of the furnace, from the baghouse,
and from the slag pile.
Sulfur dioxide emitted from the baghouse and from furnace charging
can be reduced by cleaning the effluent with a limestone-type scrubber.
Emissions from the slag-dumping operation can be eliminated by the use
of a granulating-type operation in which the molten residue slag is
quenched by a stream of water, inside an enclosure, and the effluent
gases are vented to a limestone scrubber.
Source-Receptor Relationships
Estimates of contributions from individual sources to the ambient
pollutant concentrations were made using sulfur dioxide emission data
and meteorological measurements of air movement. Sources considered
were the zinc fuming plant baghouse, the smelter baghouse, and the 400-
foot stack from the smelter.
Depending upon atmospheric stability, the point of maximum impact
of the baghouses generally will occur at distances of 0.2 to 2 miles
from the source. The maximum 1-hour sulfur dioxide concentrations '
expected are 0.6 to 0.9 ppm from the Anaconda baghouse and 1 to 3 ppm
from the smelter baghouse. The maximum point of impact from the 400-
foot stack can occur at distances of 0.4 to 31 miles, and respective
1-hour values of 5 and 0.2 ppm can be expected. The maximum point of
impact from the 400-foot stack when heater and fan are operating will
occur at distances of 0.5 to 43 miles, and concentrations of 2 and 0.1
ppm, respectively, can be expected.
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Aerodynamic downwash of the baghouse emissions is expected to cause
concentrations in excess of 8 ppm within the city of East Helena.
Diffusion calculations of annual mean concentrations, neglecting
downwash phenomena, throughout the Helena Valley predict that: 75
percent of the atmospheric sulfur dioxide in Helena originates from the
400-foot stack (with fan and heater); 85 percent of the atmospheric
sulfur dioxide in East Helena originates from the baghouses; and 50
percent of the atmospheric sulfur dioxide in the area southeast of the
city of East Helena originates from the 400-foot stack.
PARTICULATE EMISSQftS
Industrial processes and fuel use account for 98 percent of the
estimated particulate emissions. Unpaved streets in the area emit an
unknown quantity of particulates; the seriousness of these emissions
is compounded by the number of unpaved streets in use and by the
cadmium and lead contamination of road dirt in East Helena.
LEAD SMELTER
When operating at a normal production rate of 1,200 tons of feed
per day, the smelter is estimated to emit 1,000 pounds of particulate
matter that contains substantial concentrations of arsenic, cadmium,
lead, and zinc. Known points of emission include the material-receiving
area during unloading of concentrates, the outside yard area used for
storage of concentrates, and the baghouse through which off-gases from
the sintering furnace pass to the atmosphere.
Only minimal efforts have been made by the company to control
emissions from material handling. Particulates in the off-gases of the
blast and reverberatory furnaces are estimated to be 99 percent controlled
by the baghouse. Particulates in the off-gases of the sintering furnace
are controlled by an electrostatic precipitator reported to be 97 percent
efficient, but the reported efficiency is questionable because of the
age of this precipitator.
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Zinc Recovery Plant
Quantitative estimates of emissions are not available; but known
points of emissions are the furnace, the baghouse, the slag dump, and
the coal pulverizer. When slag is charged into the furnace, copious
emissions of white fumes, believed to contain high concentrations of
cadmium, lead, and zinc, are emitted at the charging door. The product,
zinc oxide, is collected by a baghouse with a high collection efficiency.
Disposal of slag is estimated to emit in excess of 1 ton per day of
particulate matter, and coal crushing emits a sizable but undetermined
quantity of coal dust.
The company has made no efforts to control particulate emissions
from the charging of the furnace and from the dumping of slag. A bag-
house has been installed to control emissions from the coal crusher.
Source-Receptor Relationships
Neither the amounts nor the physical and chemical properties - such
as size, shape, density, and chemical content - of particles emitted by
industrial sources in East Helena are known. Quantitative estimates
cannot be made, therefore, of the distribution of particles and heavy
metals at ground level. Unlike gases, particulates attain some downward
settling velocity. Accordingly, maximum ground-level airborne particulate
and heavy-metal concentrations occur closer to the sources than do the
maximum concentrations predicted for sulfur dioxide.
WASTE WATER EMISSIONS
Lead Smelter
Plant effluent, consisting of cooling water and process wash water,
1s discharged into holding ponds that connect with Prickly Pear Creek.
Cooling water is cycled at a rate of 1,450 gallons per minute between
the plant and the retention ponds. Water from the washing of speiss is
discharged into the ponds for a period of 1 hour per day at a rate of
600 gallons per minute.
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Speiss wash water is high 1n heavy metal content. Analysis by the
State of Montana of the pond discharge into the creek indicates the
following metals and their concentrations in parts per million: arsenic,
0.8; copper, 1.1; lead, 0.6; and iron, 1.1.
Zinc Oxide Plant
Process and cooling water from this facility is held in ponds for
recirculation, with no discharges being made into Prickly Pear Creek or
any other portion of the Valley's drainage system.
SOLID WASTE DISPOSAL
Lead Smelter
Process slag from past operations is stored on plant property near
Prickly Pear Creek. Upon demand, this slag is taken to the zinc oxide
plant for further processing.
Zinc Oxide Plant
The waste slag is taken in pots by rail and dumped on the large
waste-slag pile located between the smelting complex and the city of
East Helena.
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