AIR POLLUTANT ASSESSMENT REPORT ON ARSENIC
Strategies and Air Standards Division
Office of Air Quality Planning and Standards
Office of Air and Waste Management
Environmental Protection Agency
Research Triangle Park, North Carolina 27711
July, 1976
-------
TABLE OF CONTENTS
Page #
Executive Summary ES 1
Introduction 1
Characterization of Arsenic 4
Health Effects Associated with Exposure to Airborne Inorganic
Arsenic 8
Carcinogenicity of Arsenic 9
EPA Studies in Progress 14
Air Quality Levels 18
Collection and Analysis Methods; Comparison to OSHA 18
Arsenic Concentrations in NASN Locations 19
Arsenic Concentrations Around Smelters . . 23
Sources of Arsenic Emissions and Appropriate Control Technology .... 29
Copper Smelters 31
Lead and Zinc Smelters 41
Pesticide Production and Use 44
Glass Manufacture 46
Coal Burning 48
Other Sources 5^
Implications and Current Activities 52
References 59
-------
AIR POLLUTANT ASSESSMENT REPORT ON ARSENIC '
Executive Summary
Both EPA and the Occupational Safety and Health Administration
have initiated programs to reexamine potential problems associated
with inorganic arsenic based on presently available evidence which
implicates inorganic arsenic as a carcinogen for man. This report
summarizes the available data on arsenic as an ambient air contaminant,
outlines the areas where information is lacking, and describes briefly
the EPA actions underway or to be implemented to provide the needed
information.
Background
Elemental arsenic combines readily to form a variety of inorganic
and organic compounds (organic compounds contain an arsenic-carbon bond).
Although both the inorganic and organic forms can be toxic, generally in
high dosages, there is no evidence that organic arsenic compounds are
carcinogenic. Hence, this report focuses on inorganic arsenic.
Arsenic and its various compounds are widely distributed in small
amounts in the soils and waters of the world. Traces of arsenic are
also found in foods, particularly seafoods, and in some meats and
vegetables. Arsenic in the ambient air generally results from processing
of sulfide ores and the production or use of arsenical compounds. Arsenic
trixoide, the compound used in the synthesis of many other arsenic
-------
,.S 2
compounds, is obtained primarily as the by-product of the smelting of
copper, zinc, or lead ores. U.S. consumption of arsenic trioxide has
been estimated at 32,000 tons annually; the primary use is for pro-
duction of arsenical herbicides and insecticides. In addition to such
agricultural uses, arsenic trioxide is employed in the manufacture of
glass, wood preservatives, and nonferrous alloys. Small quantities of
arsenic trioxide are added to formulations for Pharmaceuticals, pigments,
poultry feed additives, and inorganic chemicals.
Health Concerns
There is epidemiologic evidence that implicates inorganic arsenic
as a human carcinogen. This evidence is based primarily on findings
of excess lung cancer mortality among smelter workers and employees
of pesticide plants exposed to airborne concentrations of various
inorganic arsenic compounds. To date, however, no human or animal data
have been developed which demonstrate a causal relationship or a dose
response relationship between lung cancer and exposure to airborne
inorganic arsenic. Nevertheless, based on the excess lung cancer
mortality noted among worker populations, many scientists believe that
inorganic arsenic is a carcinogen.
In order to protect these worker populations, OSHA proposed in
January, 1975, new occupational.standards for exposure to inorganic arsenic
which are more restrictive than the current standard of 500 micrograms/cubic
o
meter (yg/m ), 8-hour average. The new OSHA regulation proposes an "action
level" of 2 yg/m , 8-hour average, and a permissible exposure limit
-------
ES 3
of 4 yg/m , 8-hour average. The proposed standards are based on a
"level of detectability" as defined by the National Institute of
Occupational Safety and Health, rather than on a recognized health
effects threshold. OSHA anticipates promulgation of the final standard
for inorganic arsenic during 1976. It is uncertain at this time what
the level of the promulgated standard will be.
The possibility that a health problem associated with inorganic
arsenic may extend to the communities surrounding industrial sources
of arsenic emissions has been the subject of several recent studies.
Increased lung cancer has been reported among male and female residents
living near the copper smelter and mine in Anaconda, Montana. The
National Cancer Institute (NCI) released a study showing excess mortality
from respiratory cancer in counties where copper, lead, and zinc smelters
are located, but not in counties where other non-ferrous smelters are
located. The authors postulate that the excess respiratory cancer
can be associated with neighborhood exposure to inorganic arsenic; how-
ever, they also indicate that other industrial agents may contribute to
the hazard. None of the studies cited have been able to identify or
estimate a health effects threshold.
EPA is undertaking several comprehensive community health studies
around industrial sources of inorganic arsenic emissions to better define
the health effects which may be associated with community exposure to
airborne inorganic arsenic. Results of these studies, available within
the next two years, should provide a basis for a more conclusive evaluation
-------
ES 4
of the relationship between lung cancer and community exposure to
inorganic arsenic.
Air Quality Levels
Ambient arsenic is collected by hi-volume (hi-vol) particulate
samplers. The hi-vol filters can then be analyzed for arsenic by one of
several methods including atomic absorption, neutron activation analysis,
and optical emission spectroscopy. The atomic absorption (AA) technique
has the lowest level of detectability (0.001 yg/m ). Although there has
been criticism of the hi-vol collection method (specifically, that
arsenic in the vapor phase passes through or evaporates from the filter
medium), the air quality data accumulated are valuable in indicating
relative arsenic concentrations. Particulate samples taken at 280
National Air Surveillance Network (NASN) sites in 1974 were recently
analyzed for arsenic by the AA method. During 1974, 73 of the 280 sites
showed quarterly average values of 24-hour averages above the AA lower
3
detection limit of 0.001 yg/m ; 62 of the 73 sites exhibited quarterly
3 3
values between 0.001 yg/m and 0.02 yg/m , one of the 62 sites is located
near a non-ferrous smelter. The remaining 11 sites had quarterly values
3 3
between 0.02 yg/m and 0.17 yg/m . Among the sites in this latter
group, seven are located in heavily industrialized areas and have arsenic
3 3
levels between 0.02 yg/m and 0.08 yg/m , the remaining four sites in
this group are located near non-ferrous smelters and have air quality
levels ranging from 0.03 yg/m to 0.17 yg/m . Of the 73 sites with
values above the AA lower detection limit, five sites are located near
non-ferrous smelters. The average of quarterly composite values for the
-------
ES 5
5 smelter sites above the limits of detectability is 0.06 yg/m while
3
the average of values for sites not located near smelters is 0.01 yg/m .
Since the available air quality data indicate that arsenic levels for
most urban areas are below the level of detectability using AA, it
appears that arsenic is not a widespread urban air pollution problem.
Because arsenic concentrations around non-ferrous smelters are
substantially higher than general urban levels, available air quality
data for 1973 and 1974 from around 11 smelters were analyzed for arsenic.
The data for nine of the smelters were gathered by EPA during a national
smelter study of sulfur dioxide (S02) air quality problems; however
samples were available for analysis for arsenic. The maximum quarterly
3
average arsenic concentration observed in this study was 0.49 yg/m at
the Bunker Hill lead and zinc smelting complex in Kellogg, Idaho. The
3
second and third highest quarterly averages were 0.46 yg/m observed
3
around the Kennecott copper smelter in Garfield, Utah and 0.38 yg/m
observed at the Anaconda copper smelter in Anaconda, Montana.
The ASARCO copper smelters in Tacoma, Washington, and El Paso,
Texas, were not a part of the national smelter study, but available data
indicate higher ambient air concentrations near these plants than those
observed around the smelters included in the smelter study. For both
ASARCO smelters, sites were 0.3 miles from the plant. In 1973, a maxi-
3
mum quarterly average of 4.86 yg/m was obtained near the Tacoma smelter.
The smelter at El Paso, Texas, had maximum quarterly values of 1.81 and
0.80 yg/m3 in 1973 and 1974 respectively.
The available smelter data indicate that monitor location may
significantly influence observed ambient arsenic concentrations. Since,
-------
ES 6
in the case of the nine plant smalter study, monitoring sites were
located to obtain sulfur dioxide concentrations, the arsenic levels
recorded may not be the highest that exist. More data will have to be
acquired and analyzed to confirm this possibility.
Air quality levels of arsenic around glass production plants and
coal-fired power plants, because of their potential for arsenic emissions,
were also investigated using dispersion modelling techniques and any
available information. There are presently no arsenic air quality data
available for neighborhoods around glass plants. Consequently, a variety
of glass plant configurations were evaluated using dispersion models.
It was found that for a large plant with a typical 100 foot stack and
with a capacity of 300 tons per day, the maximum 24-hour average value
3
was 0.15 yg/m assuming 50 percent control and worst cast meteorological
conditions. Because this value is low when compared to observed 24-hour
3 3
maximums of 15.7 yg/m at the Tacoma smelter and 8.2 yg/m at the El
Paso smelter and use of arsenic in glass is decreasing, glass plants do
not appear to pose an arsenic problem.
An assessment of arsenic emissions and air quality data associated
with coal-fired power plants was completed. Observed ambient concentrations
around a 710 MW power plant in Maryland indicate 24-hour arsenic levels
3
ranging from 0.004-0.008 yg/m . Using actual arsenic emissions information,
dispersion modelling of arsenic concentrations in the vicinity of three
power plants in EPA Region VIII indicate maximum 24-hour arsenic levels
3 3
of 0.004 yg/m and 0.009 yg/m , with one plant having levels well below
3
0.001 yg/m . Dispersion modelling was also used to estimate arsenic
concentrations around 51 power plants under worst case conditions.
-------
ES 7
This analysis indicated that only three of these plants had maximum 24-
o
hour arsenic concentrations greater than 0.1 ng/m ; maximum values for
none of the plants exceeded 0.2 pg/m . The estimated and observed
values of arsenic around power plants were much lower than observed data
around non-ferrous smelters and in most instances worst case conditions
were used to estimate the arsenic concentrations. Consequently, power
plants do not appear to represent a significant source of arsenic.
Sources of Arsenic Emissions
Inorganic arsenic is emitted from several sources, including
copper, lead, and zinc smelters, glass production plants, coal burning
facilities, cotton gins and arsenic compound production plants. Based
on available emissions and air quality data on arsenic, nonferrous
smelters appear to be the sources of most concern. Emissions also
result from the application of pesticides for agricultural purposes.
Although the total emissions from agricultural use is relatively large
(2740 tons), most of the arsenic released is in the organic form (2300
tons). Moreover, agricultural emissions of arsenic are highly diffused
geographically.
Based on an estimate of nationwide emissions, copper smelters make
the greatest contribution (61.1 percent) to total emissions of inorganic
arsenic. This is true not only in the aggregate, but on an individual
plant basis also. Arsenic emissions from copper smelters come from the
roaster, furnace, and converter process operations and occur as fugitive
dust as well. Current control practices include use of multicyclones,
balloon flues, and electrostatic precipitators (ESP's). Baghouses have
the potential for greater control of arsenic emissions from copper
-------
,S 8
smelters, but they are not presently widely used on such plants. However,
the specific amount of arsenic emission reductions achieved when particu-
late controls are employed has not been evaluated.
One of the smelters with significantly higher ambient levels of arsenic
than other sources is the ASARCO copper smelter and arsenic plant in
Tacoma, Washington. It is the only U. S. smelter which has an arsenic
production capability and is the only facility in the country capable of
handling ore concentrates containing up to 13% arsenic, and residues
(containing up to 21% arsenic) from other smelters. Ores processed by
the other smelters contain less than 1% arsenic.
Emissions of inorganic arsenic from the Tacoma smelter are esti-
mated at 190 tons for 1975, a reduction from the 310 tons emitted in
1974. This reduction is partially attributed to control efforts which
have been implemented at the Tacoma smelter. The Board of Directors of
the Puget Sound Air Pollution Control Agency has recently granted
ASARCO-Tacoma a 5-year variance from compliance with the Puget Sound Air
Pollution Control Agency regulation requiring 90 percent sulfur dioxide
control; the smelter currently achieves approximately 51 percent control
of sulfur dioxide, but avoids violation of the national ambient air
quality standard for SOp with a supplemental control system. During the
variance period, ASARCO-Tacoma will implement several actions to reduce
arsenic emissions. EPA Region X and the Office of Air and Waste Manage-
ment are currently evaluating the emission control strategy to be
implemented at the Tacoma smelter, as well as defining and determining
the impacts of reasonably available control technology for arsenic and
sulfur dioxide. The variance granted by Puget Sound will have to be
reviewed by EPA as a part of the Washington State implementation plan
and approved or disapproved by EPA for inclusion in the plan.
-------
ES 9
Recent preliminary estimates show that the Anaconda copper smelter
in Anaconda, Montana, has the potential for higher arsenic emissions
than the other copper smelters. The Anaconda smelter processes a large
amount (2000 tons) of ore concentrate each day; the concentrate is high
in arsenic content (0.97 percent). Participate emissions range from
approximately 20 to 30 tons per day; approximately 20 percent.of this
total is arsenic. Consequently, arsenic emissions ranging from approxi-
mately 1300 to 2000 tons per year have been estimated for 1974.
During 1975, Anaconda undertook a major project to convert their
smelting operations from reverberatory furnaces to a fluo-solids roasting
and electric furnace process and to install a baghouse rated 99.7
percent efficient for particulate removal. These changes are expected
to greatly reduce arsenic emissions once they become operational at the
end of 1976. ORD-Cincinnati is working with Anaconda to develop proce-
dures for disposal of the flue dust containing arsenic from the new
smelting operation at Anaconda.
Several of the other copper smelters (ASARCO-E1 Paso and Kennecott-
Garfield) and one lead-zinc smelter (Bunker HilVKellogg) are potential
sources of significant arsenic emissions, although estimates put their
emissions below those of ASARCO-Tacoma and Anaconda. Available air
quality data tend to support the emission estimates.
The ASARCO-E1 Paso smelter is already on a compliance schedule
resulting from a court suit brought against the smelter by the City of
El Paso and the.Texas Air Control Board; the schedule requires instal-
lation of additional particulate and S02 control equipment, which are
-------
iS 10
expected to greatly reduce emissions of arsenic and toxic metals from
the smelter. A continuous copper smelting process which will minimize
pollutant losses, including arsenic, 1s being installed at the Kennecott
copper smelter in Garfield, Utah. Finally, the Bunker Hill smelting
complex in Kellogg, Idaho, must comply with regulations which require
permanent constant emission control technology for sulfur dioxide,
control of fugitive losses and proper operation and maintenance of
sulfuric acid plants; compliance with these regulations which are
included in the State implementation plan or promulgated by EPA as part
of the plan should also result in reductions of arsenic losses from the
plant.
Implications and Current Activities
Although arsenic does not appear to be a widespread urban air
pollution problem, the available data indicate that non-ferrous smelters
are significant sources of ambient arsenic. Their emissions were sub-
stantially higher than any other sources evaluated with copper smelters,
especially the Tacoma and Anaconda smelters, being prominent. Assuming
a log-normal distribution of the air quality data (which may not be
entirely valid for smelters using supplementary control systems for SCL
because of the potential for reduced maximum values), the calculated
maximum 8-hour average around several non-ferrous smelters was near or
o
above the proposed OSHA 8-hour standard of 4 yg/m for occupational
exposure to arsenic.
However, it is difficult to make a rational comparison of the
proposed OSHA standard and the observed air quality levels. Not only
-------
ES n
are the receptor populations quite different, but the OSHA standard,
while it was proposed because of health concerns, is derived from a
detectability definition rather than known or even estimated dose- •
response data. Indeed, there is a lack of such data on which to base a
reasonable judgment regarding the health threat of the ambient arsenic
levels found to exist. Nevertheless, because ambient levels of arsenic
around non-ferrous smelters are elevated above levels observed in most
urban areas, EPA and state and local agencies should regard arsenic
emissions from smelters as a potential problem requiring further study
and possibly control.
No other sources of arsenic emissions identified to date had high
ambient arsenic concentrations associated with them. As described
earlier, calculated worst case maximum 24hour ambient concentrations
around glass plants are much lower than the maximum levels observed
around the ASARCO smelters in El Paso and Tacoma and around other
smelters as well. Assuming worst-case conditions, dispersion modelling
techniques employed to determine maximum 24-hour ambient arsenic con-
centrations around power plants and limited observations indicate levels
substantially lower than around most smelters for which data are avail-
able. Although no air quality data for cotton gins are available, their
inorganic arsenic emissions are relatively small and highly seasonal.
Similarly, inorganic arsenic emissions from pesticide production and use
are also small, and in the case of application for agricultural purposes,
very highly diffused.
-------
ES 12
Five non-ferrous smelters which appear to be important sources of
arsenic emissions have been identified. Current information indicates
that reductions in arsenic emissions from these smelters will be achieved
in the next several years as the result of major process modifications
or control efforts underway or soon to be implemented.
Several programs are underway within EPA to provide additional data
on health effects which may be associated with exposure to inorganic
arsenic. The Office of Research and Development (ORD) has recently
completed the first phase of a two phase epidemiological study to pro-
vide a data base for determining the health effects relationship between
body burdens and exposure to inorganic arsenic and other metals in the
community. The second phase of the study will be conducted in communities
around six nonferrous smelters; these smelters will be selected based
upon the findings of the first phase of the study. The Office of Air
and Waste Management (OAWM) will coordinate with ORD in the selection of
smelters for this study. The Office of Toxic Substances (OTS) has
undertaken a prospective study in Tacoma to attempt to relate changes in
motor nerve conduction velocity with exposure to inorganic arsenic.
Researchers from Johns Hopkins completed a preliminary mortality study
for OTS around the Allied Chemical Company in Baltimore, Maryland, which
formerly manufactured arsenical pesticides; Johns Hopkins is proposing
further investigations around this plant.
Efforts are also being implemented within EPA to develop more
information on ambient concentrations of arsenic, as well as emissions
and appropriate control technology. To more precisely define the dis-
-------
ES 13
tribution of arsenic concentrations close to smelters, OAWM has contacted
State and local control agencies to acquire additional air quality data;
limited data were obtained. Limited air quality monitoring will be
included in the ORD epidemiology study around six smelters. In addition
to these projects, ORD is evaluating the effectiveness of the current
method for arsenic collection and analysis and, if necessary, a more
reliable method will be developed. If the method is found to be deficient,
the findings of this report will be reevaluated. ORD-Cincinnati has
begun a detailed assessment of the non-ferrous smelter industry; signi-
ficant efforts will be undertaken to determine appropriate control
technology for smelters with emphasis on the problems associated with
trace elements, such as arsenic.
Because the air quality levels and estimated emissions of arsenic
around some non-ferrous smelters appear to be significant, regulatory
action on arsenic may be necessary. However, the current data base is
not comprehensive enough to support such action. The studies and
projects within EPA which are underway or soon to be initiated should
provide sufficient basis for and background upon which to make a decision
regarding regulatory action on arsenic. The decision point is probably
two years off, but in the interim OAWM will initiate studies to develop
control technology information to be used in the regulation of arsenic
emissions from smelters. As a result of the OAWM work, the Agency will
be in a position to act quickly to regulate arsenic if warranted.
-------
AIR POLLUTANT ASSESSMENT REPORT ON ARSENIC
INTRODUCTION
1-3
Recent findings of excess lung cancer mortality among worker
populations exposed to airborne concentrations of various inorganic
arsenic compounds have implicated inorganic arsenic as a human carcin-
ogen. The possibility that a similar problem may extend beyond the
work place to the communities surrounding industrial sources of air-
borne inorganic arsenic has resulted in the current assessment and
the initiation of several EPA research projects on health effects
associated with inorganic arsenic.
The Occupational Safety and Health Administration (OSHA) has also
reacted to the recent findings by proposing, on January 21, 1975, the
4
following standard for workplace exposure to inorganic arsenic:
•3
4 micrograms/cubic meter (yg/m ) 8-hr, time weighted average
Permissible exposure limit
•3
2 micrograms/cubic meter (yg/m ) 8-hr, time weighted average
Action level
o
10 micrograms/cubic meter (ug/m ) Ceiling over 15-minute period
Both the permissible exposure limit and the ceiling limit are levels
above which no employee exposure is permitted. By definition, the
action level is the point at which a program of worker protection and
environmental monitoring must be implemented in the work place. The
action level was set at a "non-detectable" level which the National
Institute of Occupational Safety and Health (NIOSH) defines as "the
limit of analytical sensitivity when general workroom air samples are
-------
collected for 15 minutes at a flow rate of 10 liters a minute." The
3
current OSHA standard is 500 pg/m , 8-hour time weighted average.
A hearing on the proposed standard was held in April, 1975; the final
standard is presently undergoing review and comment and is scheduled
to be promulgated during 1976. It is uncertain what the level of the
promulgated standard will be.
OSHA was able to propose the latest standard for inorganic arsenic
within several months after reviewing new epidemiologic evidence
on arsenic because they were already in the process of proposing a
new standard for arsenic based on a 1973 NIOSH criteria document.
New evidence was received from Dow and Allied on occupational exposure
to arsenic in August 1974. OSHA evaluated the studies and proposed
the current standards in January 1975. Unlike the requirements
imposed on EPA by the Clean Air Act, OSHA's legislative mandate does
not require the development of a known or estimated health level on
which to base standards, nor must OSHA define the means by which a
standard can be achieved as a part of their rulemaking. OSHA
standards must afford employees maximum health protection to the
extent feasible. The OSHA region of concern (the workplace) generally
is a readily defined and controlled environment occupied by an
essentially healthy population. In contrast, EPA must investigate
the more complex situation of potential community health problems
associated with continuous exposure of a very diverse population to
a pollutant in the ambient air.
-------
Because preliminary information indicates that exposure to inorganic
arsenic outside the workplace may pose a health problem, various program
elements within EPA are completing studies of inorganic arsenic and
assessing the need for action to reduce enviromental exposure to
inorganic arsenic. This report summarizes the data currently available
on inorganic arsenic as an air contaminant. It is divided into five
sections: characterization of arsenic; health effects; observed
ambient levels; sources and emissions; and implications of the data
and current EPA actions.
-------
CHARACTERIZATION OF ARSENIC
Arsenic occurs in nature primarily as inorganic compounds; it occurs
very infrequently in an elemental state. It also forms a variety of
organic compounds, i. e. compounds containing an arsenic-carbon bond.
Both organic and inorganic compounds can be toxic to man, but. unlike
inorganic arsenic, organic arsenic compounds have not been associated
with lung cancer in worker populations. Because EPA's concern with
regard to environmental exposure to arsenic is caused primarily by
the implication that inorganic arsenic is a carcinogen, this paper
focuses on inorganic arsenic.
Arsenic is found primarily in the ores of metals such as copper,
lead, zinc, gold and silver; such ores may contain up to 6 percent
arsenic by weight. However, arsenic and its compounds are widely
distributed in nature and are found in trace amounts in most matter.
Surveys of soils in the U. S. show that arsenic levels range from 0.2
to 40 parts per million (ppm) and average 5 ppm for uncontaminated
soil. Sea water contains from 0.006 to 0.03 ppm arsenic, but this
level may increase near the mouths of estuaries which drain industrial
areas. Fresh water normally contains very small amounts of arsenic
unless contaminated by effluents containing arsenic from industrial
sources.
Arsenic can be found in the ambient air, generally the result of
processing non-ferrous metal ores and the production or use of arsenical
compounds. Arsenic enters the atmosphere primarily as particles which
-------
either wash out or fall out and may remain in the soil for long periods;
such particles can be reentrained as wind and/or traffic disturb the
earth's surface. Arsenic in the soil can be taken up in certain types
of vegetables and eventually ingested by man; it is also subject to
run-off into rivers and streams which can result in higher than normal
levels of arsenic in fresh water.
The inorganic arsenic produced commercially enters end product
manufacturing in the form of arsenic trioxide which is obtained as a
byproduct of the smelting of sulfide ores of copper, zinc or lead.
Arsenic trioxide is the basic commodity which is used in the synthesis
of most other arsenic compounds; most such compounds, when heated in
air, are converted to this toxic white powder.
Arsenic trioxide is currently produced commercially by only one
facility in this country—the ASARCO copper smelter and arsenic plant
in Tacoma, Washington. ASARCO's commercial output is estimated at
12,000 tons of arsenic trioxide per year. U. S. consumption of arsenic
trioxide totaled approximately 32,000 tons in 1974, with the differnce
being primarily imported from Mexico, Sweden, and France. U. S.
consumption of arsenic over the past ten years has ranged from a high
of 34,500 tons in 1967 to a low of 23,600 tons in 1972; consumption
for 1973, 1974 and estimated for 1975 appear to be fairly stable,
averaging about 30,000 tons per year.
Arsenic trioxide has a wide range of industrial applications in
the U. S. as illustrated in Table 1. The toxic nature of arsenic
-------
TABLE 1
DISTRIBUTION OF MAJOR INDUSTRIAL
CONSUMPTION OF ARSENIC TRIOXIDE IN THE UNITED STATES
Industrial
Category
Agricultural
Chemicals
(Pesticides)
Glass and
Glassware
Industrial
Inorganic
Chemicals
(Catalysts-reagents)
Nonferrous alloys
(Copper-Lead)
Medicinal Chemicals
(Agricultural)
Total
Arsenic Trioxide Consumption
(Percent)
1968 1971 1974
1
77% 70% 67%
18% 20% 9%
"
> 4%
1% _
16%
10%
6%
2%
100%
100%
100%
Total Estimated Consumption
31,600
tons
23,900
tons
32,000
tons
Sources: ASARCO, The Economic Impact of Proposed OSHA Airborne Arsenic
Standards, June 1975.
Stanford Research Institute, Chemical and Economics Handbook,
January, 1973.
Bureau of Mines, Minerals Yearbook, 1973.
-------
compounds accounts for their major use: approximately 67% of the
arsenic consumed in this country is used by the agricultural chemicals
industry to produce pesticides including insecticides, herbicides and
wood preservatives. Utilization of organic arsenical pesticides is
increasing while use of inorganic varieties is decreasing. Arsenic
trioxide is also used in the manufacture of glass as a refining agent,
but such usage in the U. S. has decreased and is continuing to decline.
On the other hand, use of arsenic trioxide in industrial chemicals for
preservatives, pigments and reagents is increasing. The pharmaceutical
industry employs a small portion of arsenic trioxide in some of its
formulations.
Approximately 6 percent of the total arsenic trioxide consumed
in the United States is refined to produce arsenic metal which is
used as an alloy. Arsenic metal, when used in small amounts with
lead, increases the hardness of lead-base bearing alloys and forms
more perfect spheres when making lead shot. Small amounts of arsenic
increase the corrosion resistance and toughness of copper.
-------
8
HEALTH EFFECTS ASSOCIATED WITH EXPOSURE TO
AIRBORNE INORGANIC ARSENIC
Arsenic may be absorbed by man through inhalation, ingestion or
skin absorption. Any arsenic taken into the body is excreted primarily
in the urine, feces, hair, nails, sweat, and epithelium. Arsenic
may be found in small quantities in the blood, all the tissues, the
bones, the nails and the hair. The toxic effects of inorganic arsenic
compounds on man, following oral ingestion, are well known. Both
acute effects (having a short and relatively severe course) and chronic
effects (persisting over a long period of time) have been observed.
Some of the effects of acute arsenic poisoning are: vomiting, nausea,
diarrhea, irritation, inflamation and ulceration of the mucous mem-
branes and skin, and kidney damage. Chronic inorganic arsenic poisoning
results in dermatitis, muscular paralysis, visual distrubances, and
liver and kidney damage. Both acute and chronic poisoning by inges-
tion can lead to death; a lethal dose of inorganic arsenic is reported
to range from 70 to 180 milligrams, although very few deaths each
year are currently attributable to ingestion of arsenic.
Both external and internal injury may also result from air
exposure to inorganic arsenic. Arsenic may be retained or absorbed
in the lungs, although much inhaled material is eventually cleared
from the lung and swallowed. Most absorbed arsenic is rapidly
excreted by the kidneys, but enough may remain to produce injury if
intake is continuously high. Injury from air exposure is .characterized
-------
11
2
cancer; 3 lymphosarcoma, and 6 others). In contrast, 1.2 cancer
deaths were expected among non-occupational!./ exposed individuals.
There was no evidence of excess mortality from causes other than
q
cancer. The Dow study showed a similar increased incidence of
deaths from lung and lymphatic cancer among workers at the Midland,
Michigan, facility where arsenical pesticides had been manufactured;
this facility has been closed for almost 20 years. Milham con-
ducted mortality studies in the State of Washington indicating that
smelter workers at the ASARCO smelter in Tacoma and orchard!sts show
increased mortality from respiratory cancer; men in both groups
had above normal exposure to inorganic arsenical compounds. In
contrast, a mortality study of orchardists in the Wenatchee
Valley, Washington, by Nelson et. al. of EPA concluded that death
from liver disease, kidney disease, and lung cancer was not excessive
among workers exposed to inorganic arsenical pesticides.
NIOSH has indicated that their analysis of the results of these
and other epidemiological studies evaluated provide the evidence of
excess cancer mortality associated with arsenic exposure which is
1 2
reported in their criteria document on inorganic arsenic. Based
on their findings, NIOSH recommended changes in the occupational
standard for inorganic arsenic and OSHA subsequently proposed the
new occupational standards for inorganic arsenic.
-------
In its criteria document, NIOSH evaluated 18 animal studies
involving inorganic arsenic exposures, none of which provided evidence
to establish inorganic arsenic as a carcinogen for man. Only two of
these were studies of the effects of exposure to airborne concentra-
tions and neither of these studies was designed to observe lung
cancer. At this time, no animal data have been developed which
demonstrate a causal relationship between lung cancer and exposure
to airborne inorganic arsenic. In testimony at the OSHA fact-finding
hearing on inorganic arsenic, Dr. Herman Kraybill of the National
Cancer Institute states "Arsenic stands out as the one substance
for which human carcinogeniclty has been demonstrated, but for which
an animal model has yet to be found to reproduce this effect."
Because excess lung cancer mortality among smelter workers and
other workers exposed to airborne inorganic arsenic has been observed
as described above, it has been suggested that increased incidence
of cancer may also occur among residents of communities near sources
of inorganic arsenic emissions. Evidence of excess lung cancer mor-
tality in such communities has been described in several of the
8 9
European studies. ' One of these studies found a significant
increase in lung cancer among the inhabitants of wine producing
areas of the Moselle River where inorganic arsenical pesticides
were used, but not among a similar wine producing area of the Uhr
River where arsenical pesticides were not used.
Substantial levels of inorganic arsenic have recently been
detected in vegetation, air and soil near the ASARCO copper smelter
-------
13
in Tacoma, Washington. In 1972, Milham completed a study which found
that the levels of urinary arsenic in some children near this smelter
were as high as those observed in some smelter workers. ' Studies
presented in March, 1975, by Newman, et. al.. at the New York Academy
of Sciences Conference on Occupational Carcinogenesis reported signi-
ficantly increased lung cancer among male and female residents
living near the copper smelter and mine in Anaconda, Montana.
These authors suggest that arsenic can be strongly suspected as the
etiologic agent of excess cancer among smelter workers and women in
Anaconda; the excess cancer among mine workers was not suggested as
being associated with arsenic exposure.
The National Cancer Institute has just released a study which
assessed lung cancer mortality in male and female residents of counties
throughout the U. S. that contain non-ferrous smelters. Average
mortality rates from lung cancer for white males and females in the
U. S,, 1950-1969, were significantly elevated in some counties with
copper, lead or zinc smelting or refining industries, but not in
counties where other non-ferrous ores are processed. Although part
of the excess mortality from lung cancer in males can be attributed
to employment in smelters or other factors, the study found that it
is unlikely that occupational exposure alone could account for the
large excess mortality in males or the increased mortality in females
living in the counties. The authors suggest that the most likely
explanation for the excess lung cancer mortality is neighborhood
exposure to airborne inorganic arsenic. However, they also indicate
-------
that other industrial agents may contribute to the hazard. Also,
as concluded by the International Agency for Research on Cancer,
because the influences of other constituents of the working atmosphere
cannot be determined, the causative role of arsenic in such cases is
uncertain.
Although these studies are not conclusive in determining that
inorganic arsenic is the causal factor in the increased incidence of
lung cancer, they do suggest a relationship between exposure to air-
borne inorganic arsenic and respiratory cancer. Whether or not arsenic
is a causal factor in the excess of lung cancer observed is less certain
due to the lack of evaluation of other possible carcinogens which are
also present. However, the evidence presently available is considered
by most scientists concerned with the problem to indicate the need
for improved exposure control. In an attempt to provide a better
indicator of the relationship between lung cancer and exposure to air-
borne inorganic arsenic, EPA has undertaken several comprehensive
community health studies around industrial sources of inorganic arsenic
emissions.
EPA Studies in Progress
EPA has long been concerned with arsenic as an air contaminant;
17 18
studies completed in 1968 and 1972 investigated arsenic ' concen-
trations. More recently, the association of inorganic arsenic with
respiratory cancer has resulted in new EPA studies on arsenic. Several
studies are currently underway within EPA to assess the health effects
associated with exposure to airborne inorganic arsenic in the community.
-------
15
The National Academy of Sciences is nearing completion of a study for
EPA's Office of Research and Development (ORD) which will summarize
and evaluate the available scientific and technical information on
inorganic arsenic, including health effects. Once this study is
received, ORD will prepare a Scientific and Technical Assessment
Report (STAR) on inorganic arsenic. The first draft of the STAR
on arsenic is anticipated before the end of 1976.
ORD is working with the L). S. Center for Disease Control in
Atlanta in a study to collect and analyze blood, urine and hair
samples from 100 children living near each of 22 copper, lead and
zinc smelters, as well as house dust from the homes of these children.
The samples have been collected and analyzed for arsenic, lead,
cadmium, zinc, and copper. The results of the analyses are currently
being evaluated and will be used to select six smelters which will be
investigated further as a part of an ORD epidemic!ogical project to
characterize population exposure to metals around two copper, tv/o
lead, and two zinc smelters. As in the preliminary phase, concen-
trations of arsenic, cadmium, copper, lead, zinc and manganese will
be determined in air, soil, water, and house dust in the six com-
munities selected for study. Blood, urine, and hair samples from
240 non-occupationally exposed individuals in each community will
be analyzed and a health questionnaire will be administered to each
individual. This study should provide a data base for determining
the relationship between body burden and exposure to inorganic arsenic
and other metals in the community. The study will be completed
by the end of 1977.
-------
16
The Office of Toxic Substances (OTS) has underway a two-phase
study to assess the health effects associated with non-occupational
exposure to airborne inorganic arsenic. The first phase of the
study was a pilot effort by Johns Hopkins University to assess cancer
mortality for 1970-1972 in census tracts near the Allied Chemical
Company plant in Baltimore, Maryland. This plant manufactured
inorganic arsenical pesticides until 1973 and provided an occupational
study to OSHA which found excess respiratory cancer mortality among
workers who had been exposed to inorganic arsenic. The current
study found that lung cancer deaths were four times higher in the
census tract where the plant is located than in similar non-indus-
trialized areas in Baltimore. Johns Hopkins is proposing further
study of this area. The second phase of the OTS study will attempt
to determine whether motor nerve conduction velocity can be used as
an indicator of chronic exposure to inorganic arsenic. The community
around the ASARCO smelter in Tacoma, Washington will be the site
for the study, scheduled to begin in May, 1976. OTS anticipates
completion of this study during 1977.
The Office of Pesticides Program (OPP) is nearing completion of
a report which focuses on the critical issues of carcinogenicity
and epidemiology of arsenical pesticides. The report will assess
the potential hazards associated with use or application of arsenic-
containing pesticides. Upon release of the OPP report evaluating
the health aspects of using arsenical pesticides, the need for further
action by OPP will be considered. The Environmental Toxicology
-------
19
the material collected on the filter is analyzed for arsenic. Any
arsenic in the vapor state that passes through the filter, or is
vaporized from the participate matter collected, is not measured.
Opinion varies as to the amount of arsenic that is not measured by
the hi-vol method. However, there is a positive correlation of measure-
ment between arsenic emission levels and arsenic air quality levels;
that is, high emissions result in high air quality levels. Thus, even
though absolute levels of arsenic obtained using hi-vol measurement
might be questioned, the results can be used as a reliable indicator
of relative arsenic levels. Moreover, from a theoretical standpoint,
the amount of vaporous arsenic which is not measured is relatively
constant at ambient temperature and pressure regardless of quantity
of arsenic present; therefore, the relative contribution of vaporous
arsenic compounds would be greater at the lower concentration levels.
The higher arsenic levels, which are the levels of principal concern,
are least likely to be significantly influenced by measurement error.
Arsenic Concentrations in NASN Locations
Quarterly composites of air quality data from National Air Sur-
veillance Network (NASN) sites for 1974 were recently evaluated for
arsenic. The quarterly composites were obtained by analyzing a single
sample consisting of portions of from five to eight (i.e., all that
were available) 24-hour hi-vol samples taken over a 3-month period.
The analysis produces a value representing the average for that
quarter.
-------
20
Quarterly composite samples for 1974 from 280 NASN sites were
analyzed for arsenic by the atomic absorption method. Seventy-three
of the 280 sites (26 percent) exhibited air quality concentrations
3
above the lower detection limit of 0.001 yg/m for atomic absorption.
Of these 73 sites, five sites are located near non-ferrous smelters.
Appendix A provides a listing of the 73 sites and the maximum quarterly
composite value recorded for each. Figure 1 provides a frequency
distribution of the maximum quarterly composite values recorded for
the 73 sites with values above 0.001 yg/m . As Figure 1 demonstrates,
the vast majority (85 percent) of the values at the 73 sites were
3
below 0.02 yg/m . Thirty-three sites exhibited values between 0.001 yg/m
3 3
and 0.01 yg/m ; 29 sites exhibited values between 0.01 ug/m and
0.02 yg/m , one of these sites is located near a non-ferrous smelter.
••••••'•• - . • ,--•... o ••
Of the 11 sites with quarterly composite values above 0.02 yg/m , four
sites are located near non-ferrous smelters; the remaining seven sites
3 3 ; ' •
(with values ranging from 0.02 yg/m to 0.08 yg/m ) are located in
heavily industrialized areas; individual source contributions to these
levels have not been determined.
Among the highest quarterly composites recorded were several sites
located around non-ferrous smelters. Table 2 summarizes the results'
of the analysis of air quality data above the lower detection limit
for the five NASN sites located near non-ferrous smelters; four
other NASN sites are located in counties containing non-ferrous
smelters, but these latter four sites were below the lower detection
limit of 0.001 yg/m3. The NASN site at El Paso, Texas, located
3.4 miles from the ASARCO copper/lead smelter exhibited the highest
-------
22
TABLE 2. ARSENIC AIR QUALITY DATA
1
City, State
(Smelter Company, Smelter Type)
- In Descending Order of
'Smelter Study Values
Tacoma Washington (ASARCO/Copper)
Tacoma, Washington
King County, Washington (ASARCO/Copper)
Seattle, Washington (ASARCO/Copper)
El Paso, Texas (ASARCO/Copper, Lead)
El Paso, Texas (ASARCO/Copper, Lead)
Kellogg, Idaho (Bunker Hill/Lead, Zinc)
Garfleld, Utah (Kennecott/Copper)
Anaconda, Montana (Anaconda/Copper)
McGill, Nevada (Kennecott/Copper)
Miami, Arizona (Inspiration/Copper)
East Helena, Montana (ASARCO/Lead)
San Manuel , Arizona (Magma/Copper)
Douglas, Arizona (Phelps Dodge/Copper)
Douglas, Arizona (Phelps Dodge/Cooper).
Ajo, Arizona (Phelps Dodge/Copper)
Number of Sites 3
Average of Values (ug/tn )
NON-FERROUS
Year
1973
1974
1974
1974
1973
1974
1973
1973
1973
1973
1974
1974 .
1973
1974
1974
1974
SMELTERS
Highest
Quarter
1
1
1
1
3
4
4
3
3
2
1
1
4
1
2
3
AROUND
Maximum Quarterly Values in ng/m
and Distance from Smelter in Miles ( )
NASN Site , ? Smelter Study Site
Composites-1974 '* Averages-1973-743
4.856 (0.3)
0.042 (4.7)
0.026 (13.5)
0.040 (33.5)
1.805 (0.3)
0.170 (3.4)
0.487 (1.2)
0.461 (4.0)
0.384 (4.0)
0.117 (2.1)
0.102 (6.0)
0.062 (2.0)
0.032 (1.0)
0.025 (3.3)
0.014 (4.9)
0.015 (1.3)
5 11
.058 .759
Average of Maximum Quarterly Composites
for 68 NASN Sites with Values above 0.001
which are not located near smelters
.013
1
Primary or non-ferrous smelter in city/county or within 35 miles.
2
Values are obtained from one analysis of a composite consisting of portions from 5-8
h1-vol samples taken over a 3 month period. Analysis is by the atomic absorption method.
Values are obtained by averaging the results of analyses of 5-23 individual hi-vol
samples taken over a 3 month period. Analysis is by neutron activation, except for the
Tacoma, Washington site where the ASTM colorimetric method was used and the El Paso
Texas site where the atomic absorption method was used.
-------
23
o
quarterly composite of 24-hour values at 0.17 yg/m . The average of
maximum quarterly composites for the five NASN sites around smelters
3
shown on Table 2 is 0.06 yg/m , while the average of maximum quarterly
composites for the remaining 68 NASN sites with air quality values
3 3
above 0.001 yg/m is 0.01 yg/m . The average for the sites located
around smelters is several times higher than the comparable average
•5
value for the remaining NASN sites with values above 0.001 yg/m .
At present there are no data which define a dose response rela-
tionship or a definite causal relationship between exposure to inor-
ganic arsenic and carcinogenicity; consequently, it is very difficult
to assess the implications of the air quality data. Because the
analysis of the air quality data indicates that quarterly composite
values for arsenic are below the limits of detectability at 207 of
the NASN sites, arsenic does not appear to be a widespread urban air
pollution problem. However, because the average of quarterly com-
posites for five NASN sites located near non-ferrous smelters is
several times greater than the average for the other 68 NASN sites with
3
values above 0.001 ug/m , non-ferrous smelters were studied more
closely.
Arsenic Concentrations Around Smelters
Air quality data gathered by EPA in 1973 and 1974 as part of a
national smelter study have also been analyzed for arsenic. The study
was primarily concerned with sulfur dioxide levels, but particulate
samples were taken at one site near each of the nine smelters during
the 18-month period of study. The sampling sites were located at
-------
24
varying distances from the smelters primarily to monitor sulfur dioxide
ambient concentrations. Therefore, the arsenic data observed at these
sites may not represent the highest levels of arsenic in the vicinity of
the smelter. Although not included in the EPA smelter study of 1973-
1974, data from ASARCO's smelters in Tacoma, Washington, and El Paso,
Texas, were obtained and are included in the current assessment.
Air quality data on arsenic for the 11 smelters appear on Table 2.
The values displayed are the highest quarterly average values for the
1973-1974 period and appear in descending order. These averages were
calculated to facilitate a direct comparison with NASN data and are
based on individual analyses of available 24-hour hi-vol samples taken
over a 3-month period (ranging from 5-23 samples per quarter).
3
The highest quarterly average shown is 4.86 pg/m for the first
quarter in 1973 at the ASARCO smelter in Tacoma; the second highest
is 1.81 yg/m for the third quarter in 1973 at the ASARCO smelter
in El Paso, Texas. These data are higher than that obtained from the
NASN sites near these smelters; both of the smelter monitoring sites
were located within 0.3 miles of the smelters, whereas the NASN
monitoring site was 3.4 miles from the El Paso smelter and 4.7 miles
from the Tacoma smelter.
Other relatively high quarterly averages were observed at the
Bunker Hill lead and zinc smelter (0.49 pg/m1), in Kellogg, Idaho,
•3
and the copper smelters in ^arfield, Utah (0.46 pq/m ) and Anaconda,
Montana (0.38 uq/m ). The remaining six smelters had quarterly
3
averages below 0.12 yg/m . However, location of the sampling site
-------
25
is a major factor in measured ambient concentrations. As indicated
earlier, because the monitoring sites were not designed or located to
obtain maximum concentrations of arsenic, the arsenic data observed
may not represent the highest levels present in the vicinity of
smelters. Also, fugitive arsenic emissions may play an important role
close to the source. Since all of the sites in the smelter study are
located more than a mile from each smelter, the effect of fugitive
emissions is probably not a component of the air quality concentrations
of arsenic observed. Additional data are needed to confirm this, and to
provide a more accurate picture of arsenic concentrations near non-
ferrous smelters.
To gain further insight into the nature of smelter air quality
data, the distribution of daily values of arsenic was investigated.
Table 3 compares the 24-hour air quality values for the five smelters
exhibiting the highest quarterly average concentrations. Air quality
for both 1973 and 1974 are presented for the ASARCO/F1 Paso smelter
in order to show the improvement in air quality resulting from a
control program undertaken at this plant to reduce particulate and
SO- emissions. This control program is still in progress and is
expected to be completed in the next few years.
The data shown in Table 3 appear to have a log-normal distribution
which is typical for air quality data. After plotting these data on
log-probability paper, a maximum 24-hour value was estimated based
on the assumption of log-normal distribution. There are inherent
-------
Table 3. ARSENIC AIR QUALITY DATA FOR FIVE SMELTERS
Number of Daily Values
Daily Arsenic
Concentrations (yg/m3)
24-Hour Average
0- 0.200
.201- 0.400
.401- 0.600
.601- 0.800
.801- 1.000
1 .001- 3.000
3.001- 5.000
5.001- 7.000
7.001- 9.000
9.001-11.000
11.001-13.000
13.001-15.000
15.001-17.000
TOTAL
Arithmetic Means
Kennecott
Smelter
Garfield,
Utah1
15
11
7
4
1
1
'
39
i
0.35 i
Bunker Hill
Smelter
I Kellogg,
Idaho2
17
12
4
2
2
37
0.29
Anaconda
Smel ter
Anaconda,
Montana-^
10
6
5
0
2
23
0.30
ASARCO
Smelter
Tacoma, 4
Washington
3
2
2
1
4
4
3
4
2
1
0
0
1
27
3.38
ASARCO
Smel ter
El Paso,
Texasb
49
8
9
5
3
16
4
2
1
97
0.80
ASARCO
Smelter
El Paso,
Texas6
53
6
6
3
3
19
90
0.53
ro
1
Air Quality Data for 2nd, 3rd, and 4th quarters of '73 and 1st quarter of
from copper smelter.
"Air Quality Data for 3rd and 4th quarter of '73 and 1st and 2nd quarter of '74.
from lead smelter and 0.8 miles from zinc smelter.
74. Monitoring site located 4.0 miles
Monitoring site located 0.3 miles
Air Quality Data for calendar year '73.
i
Air Quality Data for calendar year '73.
Monitoring site located 4 miles from copper smelter.
Monitoring site located 0.2 miles from smelter.
3Air Quality Data for calendar year '73. Monitoring site located 0.3 miles from smelter.
DAir Quality Data for calendar year '74. Monitoring site located 0.3 miles from smelter.
-------
27
problems associated in making the log-normal assumption in attempting
to calculate a maximum 24-hour value. For example, the data may not
be truly log-normal due to the influence which supplementary control
systems could have in reducing maximum values.
However, to facilitate a comparison with the proposed OSHA standard,
maximum 24-hour values were calculated and were then used to construct
Figure 2. Figure 2 provides a means to estimate comparable air quality
values for different averaging times. For example, based on the data
distribution for the ASARCO smelter, calculations show the maximum
2
expected 24-hour values to be 37 yg/m (the maximum observed 24-hour
o
value was 15.7 yg/m in early 1973) and the maximum expected 8-hour
value to be 58 yg/m . Using the .proposed OSHA standard as a point
of reference, Figure 2 shows that the estimated maximum ambient
arsenic levels around the Tacoma smelter are clearly above the OSHA
level for all averaging times. Even with the improved 1974 air quality
levels for the El Paso smelter, the estimated maximum levels at this
smelter are also above the proposed OSHA standard. In the case of
Bunker Hill, Kennecott, and Anaconda, calculated maximum levels for the
sites where data were observed appear close to the proposed OSHA
standard at each averaging time.
-------
E
^
cr
C
Ol
(J
c
o
o
OJ
to
«=c
•000
100
10
0.1
Figure 2. Comparison of Arsenic Air Quality Data Around Smelters and OSHA Standard
._L.I..-..L.. .4.
JS.hi l?'73JDa!ta i
.j..i.iL _:
T.T .ITIi
15 minute 1-hour
8-hours 1 day
Averaging Time
1 quarter 1 year
r-o
CO
NOTE: The smelter data shown in figure^ are calculated maximum values, assuming a log-normal distribution.
-------
29
SOURCES OF ARSENIC EMISSIONS AND
APPROPRIATE CONTROL TECHNOLOGY
Inorganic arsenic can be emitted from several industrial sources
including copper, lead, and zinc smelters, glass production plants,
manufacture of arsenical compounds, and coal-burning facilities. This
section will define the magnitude of arsenic emissions from such point
sources and outline applicable technology appropriate for their control.
Table 4 provides an estimate of nationwide arsenic emissions in
the United States for 1974. As shown in the table, copper smelters
made the most significant point source contribution (61.1 percent)
toward total national arsenic emissions. Based on the high ambient
arsenic levels observed, the ASARCO copper smelter in Tacoma, Washington,
is considered one of the most important individual sources of arsenic
with emissions of 310 tons per year. Another major source is the Anaconda
copper smelter in Anaconda, Montana; recent preliminary estimates show
that arsenic emissions from this smelter may range from approximately
1300 to 2000 tons per year. The ASARCO copper-lead smelter in El Paso
and the Kennecott copper smelter in Garfield, Utah both have estimated
emissions in excess of 100 tons per year, The emissions from the 11
remaining copper smelters were assumed to be uncontrolled in calculating
emissions, and are consequently considered maximum, worst case estimates;
each smelter had arsenic emissions below 60 tons per year.
-------
30
Table 4. Estimated Arsenic Emissions in U. S. - 1974
Inorganic Arsenic
Number of Emissions Percent of
Source Plants Tons/Year Total Emissions
Copper Smelters 15 2990 61.1
Lead Smelters 6 70 1.4
Zinc Smelters 6 80 1.6
Production of Arsenical
Compounds 25 170 3.5
Application of Inorganic
Arsenical Pesticides NA 440* 9.0
Glass Production 325 400 8.2
Coal Burning
Power Plants Above
25 Megawatts 369 580 11.9
Other - 120 2.5
Misc. (Cotton Gins,
Non-ferrous alloys,
Inorganic chemicals) - 40* .8
Total 4890 100%
*Emissions from application of organic arsenical pesticides totals
approximately 2300 tons; emissions of organic arsenical pesticides
from cotton gins totals approximately 20 tons per yeaK
Calculation of Emission Estimates: Copper smelter emissions were
calculated assuming no control of arsenic emissions from the 11
smelters processing ore containing an average of less than 0.1
percent arsenic; the estimate of emissions from the Tacoma smelter
was provided by Puget Sound Air Pollution Control Agency; the pre-
liminary emission estimates for the Anaconda smelter were calculated
using information from EPA Region VIII, the Office of Air Quality
Planning and Standards, and State of Montana; the estimate of emissions
for the other two smelters was calculated assuming 90 percent control.
Arsenic emissions foijgthe remaining sources were developed using
EPA emission factors and applying an appropriate level of control.
-------
31
The other source categories have aggregate emissions well below
copper smelters; moreover on an individual plant basis the arsenic
emissions for such sources appear to be much lower than emissions
from the individual copper smelters.
Copper. Smelters
There are 15 primary copper smelters in the U. S. which employ
a total of approximately 5,000 workers who are directly involved in
the smelting process. As the map in Figure 3 indicates, all but
two of these smelters are located in seven western states and most
of them were originally constructed over 50 years ago. These facil-
ities process copper ores to recover copper and trace elements such
as molybdenum, selenium, gold, silver and in one case, arsenic. An
additional copper smelter is scheduled to be opened by Phelps Dodge
in Hi!dago County, New Mexico, in 1976; it is anticipated that
Phelps Dodge will soon close their copper smelter currently operating
in Douglas, Arizona.
The copper smelters in the U. S. handle primarily sulfide ore
concentrates which contain from 20 to 35 percent copper. Such concen-
trates also contain varying quantities of arsenic and other impurities
such as cadmium, antimony, etc. Twelve of the 15 copper smelters
process ore concentrates containing less than 0.2 percent arsenic;
three of the smelters (Anaconda, ASARCO-E1 Paso and Kennecott-
Garfield) process ores containing 0.13 to 0.96 percent arsenic; the
remaining smelter (ASARCO-Tacoma) processes domestic ore containing up
to 6 percent arsenic, foreign ores containing up to 13 percent arsenic,
and copper-bearing residues from other smelters containing up to 21
percent arsenic.
-------
COPPER SHELTERS
Q LEAD SMELTERS
ZINC SMELTERS
-------
33
One of the primary reasons that arsenic emissions from smelters
are a problem is because during smelter operations arsenic forms
fumes or fine particles which are hard to contain. Emissions of
arsenic from copper smelters can occur at several points throughout
the operation, including the roaster, furnace and converter process
operations. Fugitive emissions can account for as much as 50 per-
cent of total emissions. Such emissions result from the handling
of ore concentrates and handling and transfer of materials through-
out the smelting operation. Dusts from control devices may also
create a fugitive emission problem. Reentrained dust from open
areas and unpaved roads also may contribute to arsenic levels
observed around copper smelters. The magnitude and specific sources
of such fugitive emissions are difficult to identify.
Typically, copper smelters employ control devices on.their
main stacks and at various emission points throughout the smelter
complex. Such controls were originally installed not so much to
reduce air pollution, but to recover valuable byproducts from the
flue gas. Additional controls beyond current levels are required
for some copper smelters in response to State implementation plan
requirements or new source performance standards when plant modifi-
cations occur. Current control practices include use of multicyclones,
balloon flues and electrostatic precipitators (ESP). Most copper
smelters employ electrostatic precipitators to reduce particulate
emissions from the stack; such controls also achieve some reduction
-------
34
of arsenic-emissions but because of the small particle size of arsenic,
the efficiency for arsenic collection is not as high as the efficiency
for total particulate removal. There is some question as to the
efficiency of ESP's for capturing material below 1 micron which is
the suspected size range of arsenic. Baghouses may provide greater
control of arsenic emissions from the stack, but they have seen
only limited use in smelters and the extent of their effectiveness
for arsenic removal has not been documented.
Smelters which employ sulfuric acid plants or liquid sulfur dioxide
plants in their operation to reduce sulfur dioxide emissions also signi-
ficantly reduce arsenic emissions as well. With acid plants on smelter
converter or roaster gas streams, the arsenic which would otherwise
discharge to the atmosphere from strong gas streams is captured in
efficient particulate gas-cleaning plants to protect acid plant catalysts
from plugging and deterioration, and to a lesser degree in the product acid.
Reduction of fugitive emissions can be accomplished with better
enclosure and hooding at various points within the smelting process; the
effluent streams would in turn be vented to control devices. Other fugitive
losses can be prevented by adequate vacuum systems and clean-up procedures.
Several steps can be taken to reduce windblown or reentrained dust around
the plants. Ore concentrates and dry recycle material can be dampened
to reduce wind blown dust from stored material, reduce dust from handling
and reduce spillage. Unpaved roads around plants can be oiled or paved
to reduce wind-blown dust. Because the fugitive losses are difficult to
quantify, the reductions which can be achieved by these actions will vary
considerably from plant to plant.
-------
35
Specific Smelters
ASARCO-Tacoma
The ASARCO copper smelter in Tacoma, Washington, is unique in
several respects. The Tacoma smelter is the only facility in the
U. S. which produces arsenic trioxide for sale; production has been
as high as 12,000 tons per year. ASARCO-Tacoma is also the only
smelter in the U. S. located on a deep water port; as a result, high
arsenic concentrate ores are imported by ASARCO, comprising as much
as 30 percent of the ore it processes. This smelter is the only
facility in the U. S. capable of handling foreign ore concentrate
containing 2 to 13 percent arsenic and the copper-bearing residues
from other smelters containing up to 21 percent arsenic. Because
the Tacoma smelter processes such arsenic-rich ore concentrates and
operates an arsenic production plant, the arsenic emissions from
this plant and the associated air quality levels are higher than
those which can be attributed to most other smelters.
As noted earlier, 1974 arsenic emissions from the Tacoma
smelter were approximately 310 tons; these emissions calculations
were based on a stack test conducted by EPA in October, 1973 and
an estimate of fugitive losses by the Puget Sound Air Pollution
Control Agency (PSAPCA). PSAPCA recently estimated arsenic emissions
from the Tacoma smelter at 190 tons for 1975 (approximately 50"X stack
emissions and 50% fugitive losses). This change in arsenic emissions
from 1974 can be partially attributed to better housekeeping oractices
-------
36
and the startup of a liquid sulfur dioxide plant which removes nearly
100 percent of particulate matter including arsenic, cadmium and
lead from the converter gas stream, which contributes approximately
10 percent to stack emissions.
Currently, electrostatic precipitators (ESP's) rated at 98.7
percent efficiency operate to control particulate emissions from the
550 foot main stack of the plant. Because of the uncertainty about
the efficienty of ESP's for capturing arsenic, ASARCO tested a pilot
baghouse at the Tacoma smelter as requested by PSAPCA. PSAPCA indicates
the baghouse can reduce or eliminate visible emissions and capture a
higher percentage of the arsenical fume emissions below 1 micron which
likely escape the ESP's. As estimated by PSAPCA, a 90 percent reduction
of present arsenic stack emissions can be achieved by use of a baghouse
on the main stack.
ASARCO-Tacoma has also taken steps to control the low level sources
of fugitive arsenic emissions such as storage, loading, conveying, handling
and processing of arsenic and ore concentrates. Housekeeping improvements
have been made within various parts of the smelter and the arsenic plant
to reduce these fugitive emissions and various steps have been taken to
reduce the potential for reentrained dust around the smelter. The
converter building and the arsenic kitchens are the largest remaining
low level sources of fugitive emissions of arsenic which have not been
controlled. PSAPCA has recommended that the converter building and
the arsenic plant be completely closed to reduce fugitive emissions, but
ASARCO-Tacoma indicates such action will not be taken because of the very
undesirable working conditions which would result.
-------
37
On February 19, Puget Sound Air Pollution Control Board granted
ASARCO-Tacoma a 5-year variance from compliance with the local sulfur
dioxide regulation requiring 90 percent control of the smelter; ASARCO-
Tacoma appears to be achieving 51 percent control of sulfur dioxide and
achieving national ambient air quality standards for sulfur dioxide with
their current control program which includes use of supplementary control
systems. During the 5-year period of the variance, ASARCO-Tacoma will
implement a program to reduce arsenic emissions from the smelter. The
control program includes (1) installation of a baghouse on the roasters
and rerouting the gases from the arsenic kitchens and the metallic
arsenic plants through this baghouse; (2) routing the emissions from the
three anode furnaces, which currently go directly to the atmosphere
through two stacks, through one of the ESP's which was formerly used for
roaster gases; and (3) hooding the reverberatory slag charging area and
venting the gases to the converter flue and through an ESP.
Because the variance granted by Puget Sound must be added to the
State implementation plan for Washington, the State must submit the plan
to EPA. EPA must then review the variance, assess its impact on achievement
of the ambient standard for S02, and approve or disapprove its inclusion
in the plan. At present, a contingency of environmental groups has
appealed the decision of the Puget Sound Air Pollution Control Board
granting ASARCO-Tacoma the 5-year variance; no date has been set for a
hearing on the appeal. In addition, ASARCO-Tacoma has sued the Puget
Sound Board because the variance approved by the Board was not consistent
with ASARCO's understanding of the variance; court proceedings are
underway on this litigation. ASARCO has indicated they will complete
the internal engineering studies on the control program to be implemented,
but will not commit resources outside ASARCO until the variance granted
by Puget Sound is resolved and all litigation concluded.
-------
38
Anaconda
The Anaconda Copper Smelter in Anaconda, Montana, has the potential
for large amounts of arsenic emissions each year. Until 1965, Anaconda
produced arsenic trioxide for commercial sale much like ASARCO-Tacoma
currently does. The arsenic operation at Anaconda was discontinued due
to decreasing demand for arsenic. The Anaconda smelter has capacity for
processing a large amount (2000 tons) of ore concentrate per day; the
high arsenic content of the smelter charge averages 0.97 percent by
weight, which is second only to ASARCO-Tacoma in arsenic content of ore
concentrate. Particulate emissions from this smelter range from 20 to
30 tons per day; approximately 20 percent of the particulate emissions
is arsenic. Based on this information, preliminary estimates of arsenic
emissions from the Anaconda Smelter were calculated ,~.nd range from 1300
to 2000 tons per year, the highest estimated emissions of arsenic from
an individual source for 1974. The maximum arsenic concentration observed
in the vicinity of this smelter during the EPA smelter study (0.854
yg/m , maximum 24-hour average in 1973) is not as high as might be
expected from the high arsenic emissions; however, according to EPA
Region VIII, maximum ambient concentrations were probably not obtained.
During 1975 Anaconda initiated a major project to convert their
smelting operations from reverberatory furnaces to a fluo-soli'ds roasting
and electric furnace process. This system includes enclosed transfer
systems within the smelter operation and uses feed in the form of a
slurry. To accommodate the additional gases contained within the system,
the 400 tons per day sulfuric acid plant will be upgraded to 1100 tons
per day. In addition, a baghouse rated at 99.7% efficiency for particu-
late removal is being added to the main stack. These changes should
greatly reduce arsenic emissions from the Anaconda smelter ones they are
-------
39
fully operational and the difficulties encountered in their start-up are
overcome. Anaconda is currently on a compliance schedule which requires
completion and operation of the baghouse and major process modifications
by the end of 1976. EPA Region VIII has recently requested of Anaconda
information on control technology, a material balance for arsenic and
other information. A detailed evaluation of the Anaconda smelter will
be prepared once this information is received. Limited air quality
monitoring for arsenic may be undertaken around this smelter.
The arsenic discharged from the Anaconda smelter under the new
process will be contained primarily in the flue dust from the plant.
ORD in Cincinnati is currently working with Anaconda to develop an
appropriate means of disposing of this flue dust. Progress on the
reduction of arsenic emissions is being followed by the Montana State
Department of Health and EPA Region VIII.
ASARCO-E1 Paso
The ASARCO smelting complex in El Paso, Texas processes lead and
zinc in addition to copper. Among the available-air quality data, the
second highest ambient levels of arsenic were observed around this
smelter. In 1970 the City of El Paso and the State of Texas (Air Control
Board) brought suit against ASARCO-E1 Paso for alleged violations of the
sulfur oxide regulations of the Texas Clean Air Act and the Rules and
Regulations of the Texas Air Control Board. The suit was brought to
trial in February 1972 in El Paso. During the 10 week trial, testimony
primarily concerned sulfur dioxide and lead emissions. In May 1972, the
court entered a Judgment and Order of Injunction with the following
findings:
1. A joint ambient air sampling network was to be established
consisting of 10 hi-vol samplers. The hi-vol filters were to be routinely
-------
40
analyzed for total participates, lead, zinc, cadmium, and arsenic.
2. ASARCO was to have a new sulfuric acid plant on stream by
January 1, 1973. In addition, 16 additional emission control measures,
mostly for particulates, were to be completed during 1972.
The required installation of control equipment was completed in the
time specified. On May 14, 1975, a hearing was held to review the
situation. At the hearing, ASARCO indicated that it had made an expendi-
ture of over 22.6 million dollars in instituting various controls at the
smelting complex. Moreover, the company stated that it was proceeding
on a course of action which would require total expenditures of approxi-
mately 40.0 to 60.0 million dollars for air pollution equipment. As a
result of the hearing, the 1972 judgement was amended to specify a'
schedule of compliance for the current ASARCO emission control program.
The schedule requires progressive installation of the necessary equipment,
with all tasks to be completed by December 31, 1978.
Kennecott-Garfield
The Kennecott smelter located at Garfield, Utah is the largest of
the Kennecott Copper Corporation smelters with a capacity for processing
2400 tons per day of concentrate. The arsenic content of the ore concen-
trate averages 0.135 percent by weight. Air quality concentrations of
arsenic around the Garfield smelter were among the highest observed
during the EPA smelter study in 1973-74. Because of the significant
quantity of ore concentrates handled, the relatively high arsenic content
of the concentrate, and the air quality levels of arsenic observed,
Kennecott-Garfield appears to be among the largest emission sources of
arsenic; emission estimates in excess of 100 tons per year were calculated
using EPA emission factors and assuming 90 percent capture of arsenic.
-------
41
Kennecott-Garfield is currently operating under a compliance schedule
which indicates significant process modification will be completed by
early 1977. The modifications include replacing the reverberatory fur-
naces with three Noranda reactors, installation of water-cooled hoods on
the converters required to balance the Noranda reactor system, and the
provision of a new 800 tons per day acid plant to replace two of the
present small older units and to increase acid production capability to
2000 tons per day . A new 1200 foot stack has been completed and will
be utilized once the Noranda reactors are operational. The Noranda
process is a continuous copper smelting process designed to smelt the
copper concentrates and collect the off gases in one stream; off gases
will be cleaned and processed in the sulfuric acid plant. If this
process operates as designed, arsenic losses will be minimized.
Lead and Zinc Smelters
In general, the six primary zinc smelters do not appear to be
significant sources of arsenic emissions, even though the arsenic
content of zinc ore concentrates may reach three percent. Most zinc
plants process much smaller quantities of ore concentrate each year than
copper smelters. All primary zinc smelters in the U.S. currently
operate sulfuric acid plants which require efficient particulate gas
precleaning plants; this results in almost total elimination of particu-
late emissions including arsenic. Limited amounts of fugitive emissions
may occur during materials handling, but the magnitude of such emissions
is small. Emissions from the six zinc smelters are estimated to total
80 tons per year. One smelter, the Bunker Hill lead zinc smelter in
Kellogg, Idaho, is estimated to contribute approximately half of the
emissions.
-------
42
The six primary lead smelters located in the United States employ
two pyrometallurgical processes for the production of lead bullion.
Arsenic emissions from these smelters total approximately 70 tons/year;
the Bunker Hill lead smelter contributes significantly to the total
arsenic emissions from this source category. Such emissions are produced
by sinter machines and blast furnaces within the smelter operation.
Highly efficient baghouses are generally employed in the industry to
control all effluent streams containing particulate. In addition to the
baghouses, most of the smelters have added sulfuric acid plants which
handle the strong gas stream from the sintering machines and one plant
treats effluent streams from the sintering machines by scrubbers; these
measures significantly reduce arsenic emissions as well as sulfur dioxide
emissions from these sources. Fugitive emissions may occur in lead
plants as a result of handling ore concentrate and transfer and handling
of materials throughout the smelting operation. Again, reductions in
fugitive emissions of arsenic can be achieved by improved housekeeping
and cleanup operations.
The estimated emissions of arsenic shown in Table 4 indicate that,
in the aggregate, zinc and lead smelters do not emit sizable quantities
of arsenic. However, air quality data observed during the FPA smelter
study around the Bunker Hill lead and zinc smelting complex in Kellogg,
Idaho, indicate a maximum 24-hour arsenic concentration of 0.848 yg/m3 and
a quarterly average of .48 yq/m , the highest quarterly average observed
during the national smelter study. This smelter was examined more closely.
Bunker Hill
The Bunker Hill zinc and lead smelting complex in Kellogg, Idaho,
has the capacity to process 190,000 tons of zinc concentrate per year
and 180,000 tons of lead concentrate per year. Bunker HilTr operations
-------
43
account for 16 percent of the nation's primary lead production, 14
percent of its primary zinc production and 20 percent of-its silver
production. Ambient concentrations of arsenic around the Bunker Hill
smelting complex were among the highest observed during the EPA smelter
study. Using EPA emission factors, arsenic emissions from Bunker-Hill
are estimated at approximately 80 tons per year.
Since 1972, EPA and the State of Idaho have been involved in estab-
lishing regulations for control of sulfur dioxide from the Bunker Hill
smelter. The achievement of adequate control of sulfur dioxide should
also result in substantial reductions in arsenic emissions from the
plant. According to EPA Region X, the sulfuric acid plants presently in
operation at Bunker Hill are not properly designed, nor well maintained
and operated; in addition, the plant employs intermittent control proce-
dures which are frequently used to achieve the sulfur dioxide standard.
Much fugitive particulate matter, Including arsenic, and sulfur dioxide
escape from the plant. Consequently, the Bunker Hill smelter has arsenic
emissions well above such emissions from other lead or zinc smelters.
However, regulations have recently been finalized for the control of
sulfur dioxide from this plant, which should also result in significant
reduction in losses of particulate matter, including arsenic.
On November 19, 1975, EPA promulgated regulations for the control
of sulfur dioxide at the Bunker Hill smelting complex. Basically, EPA's
regulations require that the strong gas streams (greater.than 3.5 percent
sulfur dioxide by.volume) from the smelting operation be processed by
properly operated, designed and maintained sulfuric acid plants so that
emissions of sulfur dioxide from the acid plant are limited to 2600 ppm.
Weak streams which cannot be processed by the acid plants are vented to
-------
44
the main stack and should be limited to 2000 ppm sulfur dioxide. The
State of Idaho also has regulations applicable to the smelter for
control of fugitive emissions and for the Installation of permanent
constant emission control technology to achieve 96 percent control of
sulfur dioxide. By July 31, 1977, Bunker Hill must achieve the 24-hour
ambient air quality standards for sulfur dioxide and by July 31, 1978,
the smelter must achieve the 3-hour standard. In parallel with the
reduction 1n sulfur dioxide emissions, arsenic emissions should be
greatly reduced as the result of the necessary control efforts at
Bunker Hill.
Pesticide Production and Use
As noted earlier, 64 million pounds (32,000 tons) of arsenic trioxide
are used annually in the United States. Approximately 67 percent
(43 million pounds) of this total is used by approximately 25 firms
in the manufacture of arsenical compounds employed as insecticides,
herbicides, and wood preservatives. Most of the 43 million pounds is
used to produce six compounds: three inorganic arsenicals—lead
arsenate, calcium arsenate, and chromated copper arsenate, and three
organic arsenicals—monosodlum methanearsonate (MSMA), disodium
methanearsonate (DSMA), cacodyllc add. The arsenical pesticides
constitute 6 percent or 75 million pounds of the total pesticide
industry product output (1.3 billion pounds).
Usage of inorganic arsenical pesticides has been decreasing since
the 1940's; prior to 1940, the pesticides containing arsenic were almost
exclusively inorganic. Since that time, the use of organic arsenicals
-------
45
has steadily increased. The 1974 usage of pesticides containing lead
arsenate, calcium arsenate, and chromated copper arsenate totaled 20
million pounds of product; in comparison, combined production of
pesticides MSMA, DSMA and cacodylic acid now totals an estimated
47 million pounds. Production of miscellaneous arsenic compounds used
in small quantities throughout the industry accounts for the remainder
of the 75 million pounds of arsenical pesticides produced.
The manufacturing processes for pesticides vary considerably
from product to product, although the major process steps involved
are somewhat similar. There are four steps within the process which
have the potential for inorganic arsenic emissions. As raw materials
including arsenic trioxide are introduced into the production operation,
emissions in the form of fugitive dust occur. Fugitive emissions also
occur during packaging of the final product. Emissions may also occur
during charging, venting, and unloading of the reactor, as well as
during the purification stage. Because of the toxicity of the materials
used in pesticide production, manufacturing plants generally employ
control measures such as baghouses and scrubbers to reduce air emissions.
As a result, emissions of inorganic arsenic from such plants are low
when compared to other sources of arsenic emissions. Total arsenic
emissions from production of arsenical pesticide compounds are estimated
to be 170 tons per year; on an individual plant basis, these losses are
small.
The greatest contribution to arsenic emissions associated with
arsenical pesticides results from the actual agricultural usage of
-------
46
these pesticides. However, because the use is so widespread and the
emissions highly diffused, it is extremely difficult to quantify the
resulting ambient air quality levels. Approximately 2,740 tons of
arsenic per year are lost to the atmosphere, primarily in the form
of organic arsenic, when pesticides are employed for agricultural
purposes. (As noted earlier, organic arsenic has not been implicated
as a human carcinogen.) Inorganic arsenic emissions resulting from the
use of pesticides are estimated to be about 440 tons per year; practical
means of reducing these losses have not been identified. Losses
resulting from the use of wood preservatives are minimal as the processes
for treating wood with such compounds are totally enclosed in almost
all manufacturing operations.
Glass Manufacture
Arsenic trioxide is used in glass production as a fining agent
to assist in freeing small bubbles from the product glass, as a
decolorizer, and as an oxidizing agent. Total glass production for
1974 was approximately 24 million tons.
The use of arsenic in glass has been decreasing since 1968 when 18
percent (5,580 tons) of the arsenic trioxide used in the U.S. was utilized
by the glass industry. The glass industry consumed an estimated 2,880
tons of arsenic trioxide in 1974, which represented 9 percent of the
national consumption of arsenic trioxide. Contacts with industry
spokesmen indicate that use of arsenic trioxide in glass is still
decreasing.
Based on data from an EPA contract effort in progress, the majority
of arsenic used in the glass industry is utilized in container glass and
-------
47
in specialty glass. In all cases, the amount of arsenic used is a
minute component of the total batch of glass (0.2 to 0.7 percent of a
3000-4000 pound batch); however, less than half of the arsenic remains
in the glass. Current emissions of arsenic from glass manufacture
(approximately 325 plants) are estimated to total 400 tons per year
which represents 8.2 percent of total arsenic emissions.
To estimate ambient concentrations of arsenic around glass plants,
diffusion modeling of two glass plants was employed. A lOOton per day
glass furnace and a 300ton per day furnace were modeled. A stack height
of 100 feet and a stack diameter of 5 feet were assumed for both glass
furnaces with surrounding buildings being 40 to 50 feet in height. In
the smaller furnace, stack gas velocity was 21 feet per second and
arsenic emissions were 1.12 Ib/hour. Stack gas velocity°of 60 feet per
second and arsenic emissions of 2.68 Ib/hour were assumed for the 300-
ton furnace. The modeling analysis indicated that for both plants the
highest 24-hour average concentration will be approximately 0.3 ug/m ,
assuming no control. The annual average of 24-hour values for both
o
plants is estimated to be 0.05 yg/m . For most glass plants, an esti-
mated 50 percent control of effluent streams is being achieved, which
would reduce the maximum 24-hour average concentrations at each plant to
3
approximate 0.15 pg/m if all other parameters remain unchanged.
Because these calculated air quality levels are significantly lower than
those observed or calculated for non-ferrous smelters and because use of
arsenic in glass is declining, arsenic concentrations around glass
plants do not appear to represent an air pollutant problem at this time.
-------
48
Coal Burning
Coal generally contains from 0.08 to 16 micrograms of arsenic per
gram of coal. Power plants are the principal users of large amounts of
coal. Based upon emission factors and a 467 million ton yearly consumption
of coal, the total amount of arsenic emitted nationally as a result of
coal burning is estimated at 687 tons per year.
Emissions of arsenic from three coal-fired power plants were charac-
21
terlzed in a recent study prepared by EPA Region VIII. The trace
element emissions were determined based on sampling and a materials
balance. Plant I used cofcl containing 0.83 ppm arsenic (dry weight) in
a tangentially fired, balanced draft 330 MW boiler with three venturi
scrubbers rated at approximately 99.7 percent efficient for particulate
control. At this plant 7.5 percent of the total arsenic present left
the plant as an air emission, the remainder being captured in the scrubber
slurry or bottom ash. Emissions of 0.048 pounds of arsenic per hour,
420 pounds per year, were calculated based on measured stack sampling
results for the 330 MW boiler and normalized to total plant capacity of
750 MW. Air quality modelling of arsenic concentrations around this
3
plant indicates a maximum 24-hour concentration of 0.004 yg/m . Plant
II used coal containing 2.5 ppm arsenic (dry weight) in a tangentially
fired 350 MW boiler. A hot-side electrostatic precipitator rated at
99.3 percent efficiency provides fly ash control. At this plant, only
0.05 precent of the arsenic 1s lost in the flue gas, the remainder being
captured in precipitator ash or sluice ash. Emissions of 8.2 pounds of
arsenic per year were calculated for this boiler based on measured stack
sampling results. Dispersion modelling of arsenic concentrations around
-------
49
o
this plant indicates maximum arsenic levels well below 0.001 yg/m . At
plant III, coal containing 8 ppm was used to fire a 250 MW cyclonic
boiler with mechanical cyclone participate collectors. At this plant
12.9 percent of the total fly ash was lost to the atmosphere in the flue
gas. Approximately 20.5 percent of the total arsenic present left the
plant in the flue gas, the remainder being captured in the bottom ash
and cyclone ash. Arsenic emissions of 0.4 pounds per hour, 11,000
pounds per year (5.5 tons), were calculated based on measured stack
sampling results. Modelling of arsenic levels around this plant indicate
o
a maximum 24-hour concentration of arsenic of 0.009 yg/m .
Limited air quality data around a coal-fired power plant were
available from studies of the Chalk Point Generating Station in south-
eastern Maryland prepared by the University of Maryland Department of
22 23
Chemistry and Institute for Fluid Dynamics and Applied Mathematics. '
At the time of these studies, the Chalk Point plant had two operating
355 MW units which burn 116 tons of pulverized coal per hour, 1 million
tons of coal per year. Most of the 10 percent ash in the coal is col-
lected in Cottrell electrostatic precipitators rated at 95 percent
efficiency. Under typical conditions, particulate emissions from the
stack will be 1.2 tons/hour per unit or 28.8 tons/day per unit. Arsenic
content of the coal during the study was approximately 27 ppm by weight.
Based on in-stack sampling, arsenic emissions are approximately 0.157
pounds per hour per unit (.304 pounds per hour for the two units) or 3.8
pounds per day per unit. Observed 24-hour ambient air quality levels
associated with such arsenic emissions at the Chalk Point Plant ranged
from 0.004 - .008 yg/m3. This observed air quality data (.008 yg/m3)
-------
50
shows reasonably good agreement with worst case calculated air quality
data for Plant III in the Region VIII study.
Because limited measured data are available, an analysis was conducted
to estimate the possible 24-hour ground-level concentrations of arsenic
in the vicinity of power plants due to coal combustion. The arsenic
estimates were developed using sulfur dioxide concentration estimates as
surrogate data. Fifty-one power plants were analyzed, all of which had
24-hour sulfur dioxide concentrations exceeding the national ambient air
o
quality standard for sulfur dioxide (365 yg/m , 24-hour average). An
average arsenic content 1n coal of 5.44 ppm was used for the analysis
and losses to the atmosphere of 30 percent of the arsenic contained in
the coal were assumed; these assumptions represent worst case conditions
under which a plant is likely to operate. Maximum 24-hour averages for
each site were estimated. Of the 51 plants analyzed, none showed estimated
3
24-hour maximum values greater than 0.2 yg/m ; 3 plants had values
3 3
between 0.1 - 0.2 yg/m ; 24 plants showed values between 0.02-0.1 yg/m ;
3
15 plants had 24-hour arsenic values between 0.01-0.02 yg/m ; and nine
o
had values which were less than 0.01 yg/m .
Based on this assessment.of arsenic levels around power plants, there
appears to be reasonably good agreement between calculated and observed
arsenic air quality data at selected power plant sites. Furthermore,
the values observed or calculated under worst case conditions are low
and for no sceneries exceed 0.2 yg/m maximum 24-hour concentrations.
3
The highest observed or measured value was 0.008 yg/m with 94 percent
3
of the calculated values less than 0.1 yg/m . Even the highest calculated
worst case value is at least an order of magnitude lower than maximum
observed arsenic values for some smelters. At these relative levels,
-------
51
power plants do not appear to be a significant source of arsenic emissions,
Other Sources
Cotton ginning is a source of minor amounts of arsenic emissions,
primarily in the southeastern U.S. Arsenic may be found in the dust
particles from cotton ginning processes and in the flue gases from the
burning of cotton gin trash. There are approximately 3000 cotton gins
which operate in the U.S. from September through January. The larger
and newer gins generally employ particulate control devices which greatly
reduce arsenic emissions; however, the majority of U.S. cotton gins are
generally small operations with little or no emission control. Total
arsenic emissions from cotton gins are estimated to be 30 tons per year
of inorganic arsenic and 20 tons per year of organic arsenic. The
arsenic losses from both large and small plants are estimated to be
minimal; however, recent air quality data from around such sources are
not available.
Small quantities of arsenic emissions occur when arsenic trioxide
is used in production of nonferrous alloys and inorganic chemicals. Such
losses account for arsenic emissions of seven tons per year.
-------
52
IMPLICATIONS AND CURRENT ACTIVITIES
Based on an analysis of air quality data from cities throughout the
country, arsenic does not appear to be a widespread urban air pollution
problem. Arsenic concentrations in most urban areas are at or below the
3
analytical detection limit of 0.001 ug/m . However, non-ferrous smelters
(copper, lead, zinc) as a class are associated with relatively high
arsenic air quality concentrations, with copper smelters being the most
prominent sources. Air quality data from around eleven non-ferrous
smelters indicate arsenic concentrations several orders of magnitude
higher than observed levels in most urban areas.
To put these air quality levels in perspective, the arsenic con-
centrations around smelters were compared to the level of the OSHA
standard proposed in January, 1975. Assuming a log-normal distribution
of the air quality data, the calculated maximum 8-hour average concentration
of arsenic (expected once per year) around three non-ferrous smelters
was near the proposed OSHA standard and was higher for two smelters.
Since the OSHA proposed standard was not established at a health effects
threshold level (there Is no dose-response data on arsenic available),
1t is difficult to draw meaningful conclusions regarding public health
consequences of arsenic exposure from such a comparison. Nevertheless,
since exposure to airborne inorganic arsenic in communities around
smelters could impact public health, EPA and State and local air pollution
control agencies should regard emissions of arsenic from smelters as a
potential problem requiring further study and possibly control.
The remaining sources of inorganic arsenic emissions which have
been identified to date do not exhibit high ambient arsenic concentrations.
-------
53
Calculated ambient concentrations around glass plants indicate a maximum
o
24-hour value of 0.3 yg/m assuming no control; the observed maxima
around the ASARCO smelters in El Paso and Tacoma are at least 25 times
higher. In addition, usage of arsenic in glass is declining and most
plants have at least 50$ emission control. Evaluation of arsenic emissions
from coal-fired power plants and analysis of expected ambient maximum
concentrations of arsenic in the proximity of such plants indicate that
arsenic concentrations around this source are comparable to and lower in
most cases than levels around glass plants and are not considered significant
at this time. Estimated emissions of arsenic from cotton gins were
minimal on an individual plant basis and highly seasonal in nature.
Estimated arsenic emissions from the manufacture and use of arsenical
pesticides also are relatively small. The application of pesticides for
agricultural purposes also results in arsenic emissions; although the
total estimated emissions from such use are relatively large, most of
the arsenic released is in the organic form. Moreover, agricultural
emissions of arsenic are highly diffused geographically. Hence, based
on the current analysis, the emissions of inorganic arsenic from sources
other than non-ferrous smelters do not appear to warrant further study
at this time.
Recent preliminary estimates show that the Anaconda Company copper
smelter in Anaconda, Montana, has the potential for higher arsenic emissions
than other sources with arsenic emissions estimated at 1300 to 2000 tons
per year for 1974. Significant changes are underway at the Anaconda
smelter, most notable of which is the conversion of their smelting
-------
54
operation from reverbatory furnaces to a fluo-solids roasting and electric
furnace process and a highly efficient baghouse on the main stack.
These changes are anticipated to greatly reduce the arsenic losses from
the plant, except for some fugitive losses. ORD is currently working
with Anaconda to determine the most appropriate means for disposal of
the flue dust containing arsenic coming from the smelter. EPA Region
VIII is developing a detailed evaluation of the arsenic problem associated
with the Anaconda smelter. Limited air quality monitoring for arsenic
may be undertaken around this smelter.
The highest observed ambient arsenic levels were recorded in the
vicinity of the A.SARCO copper smelter in Tacoma, Washington. This smelter
has the second highest arsenic emissions in the country, based on an
estimate by Puget Sound Air Pollution Control Agency. The Puget Sound
Air Pollution Control Agency Board has just granted ASARCO-Tacoma a 5-year
variance from compliance with the Puget Sound sulfur dioxide regulation;
over the next 2 years the smelter will initiate several steps to reduce
arsenic emissions, including installation of a new baghouse for roaster
flue gases, rerouting the anode gases through an ESP and tighter housekeeping.
Several projects have been undertaken within EPA to better define the
sulfur dioxide and arsenic air pollution problem around the Tacoma
smelter; these projects include studies to define appropriate control
technology, and the impact of such technology. The Office of Air and
Waste Management is working with EPA Region X on a technical evaluation
of the Tacoma plant and will provide information on the effectiveness of
control measures taken at other smelters.
The ASARCO-E1 Paso smelter is currently operating- under a com-
pliance schedule resulting from court action by City of El Paso and
-------
55
the Texas Air Control Board which requires installation of additional
air pollution control equipment. The actions to be taken include routing
the gases from the roaster and sinter plant through appropriate controls
and into a 500 tons per day sulfuric acid plant; completion of a new
sinter plant with better enclosure; hooding of the converter building,
and an improved materials handling system. Significant arsenic emission
reductions are anticipated. The Kennecott copper smelter is installing
a continuous smelting process which will minimize emissions of sulfur
dioxide and particulates, including arsenic. EPA and the State of Idaho
have adopted regulations which require substantial control efforts at
the Bunker Hill smelter in Kellogg, Idaho by mid-1978. In summary, five
of the most significant sources of arsenic emissions in the country have
actions underway which should result in substantial reductions in
particulate emissions, including arsenic.
The available information on air quality levels of arsenic and
health effects associated with such levels does not permit an immediate
judgement on the need for control at the other smelters discussed in
this report. As described earlier in the section on air quality levels,
the effect of monitor location on observed ambient concentrations needs
to be clarified. OAWM has contacted appropriate state and local agencies
to discuss the subject of arsenic emissions from smelters and to determine
the availability of emissions and air quality data, or raw samples taken
close to the smelters; very limited data have been obtained. Consequently
it is difficult to identify other smelters which may require specific
control measures to reduce arsenic emissions although estimates of
emissions based on arsenic content of ore concentrate would lead to the
tentative conclusion that the remaining smelters probably do not present
an arsenic problem.
-------
56
It has been pointed out that there is some question as to the
efficiency of the collection methods currently employed for arsenic.
ORD is investigating this thesis, and if it is valid, will develop a
more accurate method. If the method is found to be deficient, the
findings of this report will be reevaluated.
Because of the paucity of data regarding community health effects
associated with exposure to inorganic arsenic and ambient air quality
data, EPA is undertaking several programs designed to provide such
information. The Office of Research and Development (ORD) has initiated
.a two phase epidemiqlogical study to provide a data base for determining
the health effects relationship between body burdens and exposure to
inorganic arsenic and other metals in the community. The analysis of
tissue samples collected from children who live near 22 non-ferrous
smelters in the first phase study will be used as the basis for
selecting sites for the conduct of a detailed epidemiology study
aroung six non-ferrous smelters. The Office of Air and Waste Management
will coordinate with ORD in the selection of smelters for this study.
The Office of Toxic Substances (OTS) has undertaken a prospective
study to attempt to define adverse health effects which may be associated
with environmental exposure to inorganic arsenic outside the work
place; the prospective study will examine motor nerve conduction
velocity as a possible indicator of arsenic exposure and will take
place in Tacoma. Researchers from Johns Hopkins completed a preliminary
mortality study for OTS around the Allied chemical company in Baltimore,
-------
57
Maryland, which formerly made arsenical pesticides; Johns Hopkins is
proposing further investigations around this plant.
The effectiveness of particulate control technology for reduction
of arsenic emissions has not been adequately determined. During the
next two years, ORD will be completing an environmental assessment of
the entire non-ferrous metallurgical industry; this study will include
consideration of multimedia pollution problems, control technology,
and a preliminary analysis of health and ecological impacts associated
with non-ferrous smelters. The evaluation of trace elements, such as
arsenic, cadmium, lead, etc., as potential problems from such smelters
will be one segment of the ORD study. OAWM is initiating studies
over the next two years to develop detailed control technology informa-
tion for the reduction of arsenic emissions from smelters. The signifi-
cant sources of arsenic emissions from smelters will be investigated;
best demonstrated arsenic emission control technology and achievable
arsenic emission reductions for weak and strong sulfur dioxide streams
will be identified by the OAWM studies.
Because the air quality levels and estimated emissions of arsenic
around some non-ferrous smelters appear to be significant, regulatory
action on arsenic may be necessary. However the current data base is
not comprehensive enough to support such action. The studies and
projects within EPA which are underway or soon to be initiated should
provide sufficient basis for and background upon which to make a
decision regarding regulatory action on arsenic. The decision point
-------
58
is probably two years off, but in the interim, OAWM will complete
studies to define control techniques to be used in the regulation of
arsenic emissions from smelters. As a result of the OAWM work, the
Agency will be in a position to act quickly to regulate arsenic if
warranted.
-------
59
REFERENCES
1. Lee, A. M., and J. F. Fraumeni, Jr.,: Arsenic and Respiratory
Cancer in Man: An Occupational Study. J. Nat. Cancer Insti.
42: 10451052, 1969.
2. Baetjar, A., M. Levin and A. Lillenfeld. Analysis of Mortality
Experience of Allied Chemical Plant. Submitted to Allied Chemical
Corporation on July 16, 1974.
3. Ott, M. G., B. B. Holder and H.L. Gordon. Respiratory Cancer and
Occupational Exposure to Arsenicals. Archives of Environmental Health
Vol. 29 November 1974.
4. Notice of Proposed Rulemaking. Standard for Exposure to Inorganic
Arsenic. Federal Register, Vol. 40, No. 14, January 21, 1975.
5. World Health Organization, International Agency for Research on
Cancer. IARC Monographs on the Evaluation of the Carcinogenic
Risk of Chemicals to Man: Some Inorganic and Organometallic
Compounds, Volume 2, IARC Publishers, Lyon, France, 1973.
6. Hill, A. B., and E. L. Faning. Studies in the Incidence of Cancer
in a Factory Handling Inorganic Compounds of Arsenic: I. Mortality
Experience in the Factory. Br. J. Ind. Med. 5_:16, 1948.
7. Robson, A. 0. and A. M. Jelliffe. Medicinal Arsenic Poisoning and
Lung Cancer. Brit. Med. J. 5351:2079, 27 July 1963.
8. Roth, F. The Sequelae of Chronic Arsenic Poisoning in Moselle
Vintagers. German Med. Monthly, 2_:172175, 1957.
9. Roth, F. Bronchial Cancer of Arsenic-Poisoned Vintagers. Virchow
Arch. Path. Anat. 33_1_:11937, 1958.
10. Milham, S. Testimony. OSHA Hearing on Arsenic Standard. April 8, 1975.
11. Nelson, W. C. , M. H. Lykins, J. Mackey, V. A. Newill, J. F. Finklea,
D. I. Hammer. Mortality Among Orchard Workers Exposed to Lead
Arsenate Spray - A Cohort Study. J. Chronic Dis. 26^ 105-118 (1973).
12. National Institute for Occupational Safety and Health Criteria for
a Recommended Standard Occupational Exposure to INorganic Arsenic,
New Criteria, 1975.
13. Kraybill, Herman Discussion of Animal Studies in Proposed OSHA
Standard for Inorganic Arsenic. Federal Register, Vol. 40, No. 14,
page 3393, January 21, 1975.
14. Milham, S. Jr., and T. Strong. Human Arsenic Exposure in Relation to
a Copper Smelter. Environ. Res. 7:176182, 1974.
-------
60
15. Newman, J. A., V. E. Archer et. al. Bronchogenic Carcinoma in the
Copper Smelting and Mining Industry. N. Y. Acad. Sci. Conference
on Occupational Carcinogenesis. March 2427, 1975.
16. Blot, William J. and Joseph F. Fraumeni, Jr. Arsenical Air Pollution
and Lung Cancer. The Lancet, pp. 142-144,'July 26, 1975.
17. Environmental Protection Agency. Helena Valley Area Environmental
Pollution Study. Office of Air Programs Publication No. AP91,
January, 1972.
18. U. S. Department of Health, Education and Welfare, Bureau of
Disease Prevention and Environmental Control. Control and Disposal
of Cotton-Ginning Wastes, PHS Publication No. 999-AP-31, 1967.
19. Lao, R. 6., R. S. Thomas, T. Terchman and L. Dubois. Efficiency of
Collection of Arsenic Tr1 oxide in High Volume Sampling. Sci'. of
Total Environment (2) 1974.
20. Anderson, David. Emission Factors for Trace Substances, EPA -
450/273001, December, 1973.
21. Environmental Protection Agency, Region VIII. Coal-Fired Power
' Plant Trace Element Study. September, 1975.
22. Gordon, Glen, Douglas D. Davis, et. al. Study of the Emissions
from Major Air Pollution Sources and Their Atmospheric Interactions,
Supported by the Research Applied to National Needs Programs of
the National Science Foundation, Grant No. GI.-36338x, November 1,
1972 - October 31, 1974.
23. Gordon, Glen, Douglas D. Davis, et. a]. Atmospheric Impact of
Major Sources and Consumers of Energy; Supported by the Research
Applied to National Needs Programs of the National Science Founda-
tion; Grant No. ESR 75-02667, October 1, 1974 - August 31i 1975.
-------
APPENDIX A
1974 AIR QUALITY DATA ON ARSENIC FROM NASN SITES*
Maximum Quarterly Composites of 24-hour Averages
in Descending Order
Maximum
Location
El Paso, Texas
Charleston, West Virginia
Philadelphia, Pennsylvania
South Charleston, West Virginia
Tacoma, Washington
Seattle, Washington
Steubenville, Ohio
King County, Washington
Baltimore, Maryland
Altoona, Pennsylvania
Birmingham, Alabama
Gadsden, Alabama
San Juan, Puerto Rico
Youngstown, Ohio
Danville, Virginia
Mobile, Alabama
Pittsburgh, Pennsylvania
West Memphis, Arkansas
Elizabeth, New Jersey
Scranton, Pennsylvania
Quarter
4
3
2
1
1
2
3
1
1
4
1
1
1
4
1
2
1
1
1
1
Quarterly Co
0.170
0.078
0.049
0.044
0.042
0.040
0.032
0.026
0.025
0.023
0.022
0.020
0.020
0.019
0.018
0.017
0.017
0.016
0.016
0.016
*Included are the 73 sites with values above lower detection limit of
0.001 yg/m3, 24-hour average; 207 sites had values below 0.001 p
-------
A-2
Richmond, Virginia 1 0.016
Rochester, New York 4 0.015
Hazel ton, Pennsylvania 1 0.015
Douglas, Arizona 2 0.014
Long Beach, California 1 0.014
Ashland, Kentucky 1 0.014
Wilkes Barre, Pennsylvania 1 0.014
Catano, Puerto Rico 3 0.014
Nashville, Tennessee 1 0.014
Phoenix, Arizona 1 0.013
Winston Salem, North Carolina 4 0.013
Davenport, Iowa 3 0.012
Oklahoma City, Oklahoma 1 0.012
Knoxville, Tennessee 3 0.012
Montgomery, Alabama 1 0.011
Ontario, California 2 0.011
Perth Amboy, New Jersy 2 0.011
Dayton, Ohio 1 0.011
Erie, Pennsylvania 3 0.011
Racine, Wisconsin 1 0.011
Cedar Rapids, Iowa 1 0.010
Bayonne, New Jersy 2 0.010
Newark, New Jersy 1 0.010
Bayamon, Puerto Rico 2 0.010
Dallas, Texas 1 0.010
East St. Louis, Illinois 3 0.009
St. Louis, Missouri 1 0.009
Niagara Falls, New York 1 0.009
All entown, Pennsylvania 1 0.009
-------
A'r3
Little Rock, Arkansas 1 0.008
Ilberville Parish, Louisiana 3 0.008
Omaha, Nebraska 3 0.008
Jersey City, New Jersey 2 0.008
Albany, New York 1 0.008
New York City, New York 2 0.008
Akron, Ohio 3 0.008
Canton, Ohio 2 0.008
Atlanta, Georgia 1 0.007
Paterson, New Jersey 2 0.007
Trenton, New Jersey 1 0.007
Buffalo, New York 1 0.007
San Bernardino,. California 2 0.006
Battle County, Idaho 1 0.006
Cincinnati, Ohio 2 0.006
Bethlehem, Pennsylvania 3 0.006
Huntsville, Alabama 2 0.005
Boise City, Idaho 1 0.005
Waterloo, Iowa 1 0.005
Kansas City, Missouri 1 0.005
Camden, New Jersey 2 0.005
Durham, North Carolina 2 0.005
Topeka, Kansas . 1 0.004
Covington, Kentucky . 1 0.001
------- |