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AIR POLLUTION ASPECTS
OF
CHROMIUM AND ITS COMPOUNDS
Prepared for the
National Air Pollution Control Administration
Consumer Protection & Environmental Health Service
Department of Health, Education, and Welfare
(Contract No. PH-22-68-25)
Compiled by Ralph J. Sullivan
Litton Systems, Inc.
Environmental Systems Division
7300 Pearl Street
Bethesda, Maryland 20014
September 1969
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FOREWORD
As the concern for air quality grows, so does the con-
cern over the less ubiquitous but potentially harmful contami-
nants that are in our atmosphere.
been identified, and available information has been summarized
Thirty such pollutants have
in a series of reports describing their sources, distribution,
effects, and control technology for their abatement.
30 pollutants.
A total of 27 reports have been prepared covering the
These reports were developed under contract
(NAPCA) by
for the National Air Pollution Control Administration
Litton Systems, Inc.
The complete listing is as follows:
Aeroallergens (pollens)
Aldehydes (includes acrolein
and formaldehyde)
Ammonia
Arsenic and Its Compounds
Asbestos
Barium and Its Compounds
Beryllium and Its Compounds
Biological Aerosols
(microorganisms)
Boron and Its Compounds
Cadmium and Its Compounds
Chlorine Gas
Chromium and Its Compounds
(includes chromic acid)
Ethylene
Hydrochloric Acid
Hydrogen SUlfide
Iron and Its Compounds
Manganese and Its Compounds
Mercury and Its Compounds
Nickel and Its Compounds
Odorous Compounds
Organic Carcinogens
Pesticides
Phosphorus and Its Compounds
Radioactive Substances
Selenium and Its Compounds
Vanadium and Its Compounds
Zinc and Its Compounds
These reports represent current state-of-the-art
literature reviews supplemented by discussions with selected
knowledgeable individuals both within and outside the Federal
Government.
They do not however presume to be a synthesis of
available information but rather a summary without an attempt
to interpret or reconcile conflicting data.
The reports are
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necessarily limited in their discussion of health effects for
some pollutants to descriptions of occupational health expo-
sures and animal laboratory studies since only a few epidemio-
logic studies were available.
Initially these reports were generally intended as
internal documents within NAPCA to provide a basis for sound
decision-making on program guidance for future research
activities and to allow ranking of future activities relating
to the development of criteria and control technology docu-
ments.
However, it is apparent that these reports may also
be of significant value to many others in air pollution control,
such as State or local air pollution control officials,
as a
library of information on which to base informed decisions on
pollutants to be controlled in their geographic areas.
Addi-
tionally, these reports may stimulate scientific investigators
to pursue research in needed areas.
They also provide for the
interested citizen readily available information about a given
pollutant.
Therefore, they are being given wide distribution
with the assumption that they will be used with full knowledge
of their value and limitations.
This series of reports was compiled and prepared by the
Litton personnel listed below:
Ralph J. Sullivan
Quade R. Stahl, Ph.D.
Norman L. Durocher
Yanis C. Athanassiadis
Sydney Miner
Harold Finkelstein, Ph.D.
Douglas A. Olsen, PhoD.
James L. Haynes
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The NAPCA project officer for the contract was Ronald C.
Campbell, assisted by Dr. Emanuel Landau and Gerald Chapman.
Appreciation is expressed to the many individuals both
outside and within NAPCA who provided information and reviewed
draft copies of these reports.
Appreciation is also expressed
to the NAPCA Office of Technical Information and Publications
for their support in providing a significant portion of the
technical literature.
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ABSTRACT
Both hexavalent and trivalent compounds of chromium are
toxic air pollutants to humans.
Inhalation of chromium com-
pounds may produce cancer of the respiratory tract.
Workers
in the chromate-producing industry have experienced deaths
caused by cancer of the respiratory tract at a rate 28 times
greater than the normal expected death rate.
Exposure to air-
borne chromium compounds may also produce dermatitis and ulcers
on the skin.
Hypersensitive people react to hexavalent chro-
mium compounds in very low concentrations (0.0001 percent
potassium dichromate solution).
The hexavalent chromium com-
pounds are more toxic than trivalent compounds.
The effects
of low concentrations of these compounds on commercial animals
and plants were not found.
Chromic acid mists have been ob-
served to discolor automobile and building paints.
The uses of chromium in the metallurgical and chemical
industries and in products employing chromate compounds, as
well as its presence in cement and asbestos, are believed to
be the most likely sources of atmospheric pollution.
In 1964
urban air concentrations averaged 0.015 ~g/m3 and ranged
as high as 0.350 ~g/m3.
No information has been found on the economic costs of
chromium air pollution or on the costs of its abatement.
Analyt-
ical methods for the determination of chromium at the concen-
trations found in the atmosphere are available.
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FOREWORD
ABSTRACT
CONTENTS
1.
INTRODUCTION
. . . . .
2.
EFFECTS
2.1
2.2
2.3
2.4
2.5
3.
SOURCES
3.1
3.2
3.3
3.4
3.5
4.
. . .
. . . . . . . . . . . .
. . .
. . .
. . .
. . . . .
. . . . .
. . .
Effects on Humans. . .
. . . . . . .
. . . . .
2.1.1 Chromium Metal and Trivalent Chromium
2 .1 . 2 Chromate s . . . . . . . . . . . . . . .
2.1.2.1 Respiratory Tract. . . . . . .
2 . 1 . 2 . 2 Sk in . . . . . . . . . . . . .
2.1.3 Carcinogenesis. . . . . . . . . . . .
2.1 .4 Nutr it ion. . . . . . . . . . . . . . .
Effects on Animals. . . . . . . . . . . . . .
2.2.1 Commercial and Domestic Animals. . . .
2.2.2 Experimental Animals. . . . . . . . . .
Effects on Plants. . . . . . . . . . . . . . .
Effects on Materials. . . . . . . . . . . . .
Environmental Air Standards. . . . . . . . . .
. . . . .
. . . . .
. . . .
........
Natural Occurrence. . . . . . . . . . . . . .
Production Sources. . . . . . . . . . . . . .
3.2.1 Metallurgical Industry. . . . . . . . .
3.2.2 Refractory Materials. . . . . . . . . .
Product Sources. . . . . . . . . . . . . . . .
3.3.1 Chemical Industry. . . . . . . . . . .
3.3.2 Chrome Plating. . . . . . . . . . . . .
3.3.3 Other Uses. . . . . . . . . . . . . . .
Other Sources. . . . . . . . . . . . . . . . .
3.4.1 Asbestos. . . . . . . . . . . . . . . .
3.4.2 Coal. . . . . . . . . . . . . . . . . .
3.4.3 Cement. . . . . . . . . . . . . . . . .
3.4.4 Welding Rods. . . . . . . . . . . . . .
Environmental Air Concentrations. . . . . . .
ABAT EMENT
. . .
5.
........
. . . . . .
. . . .
ECONOMICS
. . .
. . . . .
.......
. . .
6.
. . .
METHODS OF ANALYSIS
. . . .
. . . .
. . . . .
6.1
6.2
. . .
Sampling Methods. . . . . .
Quantitative Methods. . . .
. , . . .
. . . ,.
. . . . .
. . . .
1
2
3
3
4
6
7
9
14
15
15
15
16
17
17
18
18
19
19
19
20
20
21
22
24
24
25
25
25
27
30
32
33
33
33
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7.
SUMMARY AND CONCLUSIONS
REFERENCES
APPENDIX
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LIST OF FIGURES
1.
Typical Flow Diagram of Chromate-Producing Plant. .
49
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10.
11.
12.
13.
14.
LIST OF TABLES
1.
Mean Chromium Exposures for Workers in Chromate-
Producing Plants. . . . . . . . . . . . . . . . .
2.
Typical Composition of Chromite are
. . . .
. . .
3.
Chromium
in Body Tissues. . . . . . . . . . . . .
4.
Chromium Emissions from Coal-Fired Power Plants
5.
Chromium Concentration in Human Tissues by City,
United States. . . . . . . . . . . . . . . . . .
6.
Particle Size of Chromium Particulates in the
.Arnb i en t Air. . . . . . . . . . . . . . . . . . .
7.
Properties, Toxicity, and Uses of Some Chromium
Compounds. . . . . . . . . . . . . . . . . . . .
8.
Chromium in Human Tissue by Age in the United
Sta t e s . . . . . . . . . . . . . . . . . . . . .
9.
Animal Exposures to Chromates
. . . . .
. . . . .
Consumption of Chromite in the United States
. . .
U.S. Consumers of Chrome are. .
. . . .
. . . . .
Production of Chromium Chemicals
. . .
. . . . . .
Chromium Content of Portland Cement
. . . .
. . .
Concentration of Chromium in the Air.
. . .
. . .
11
12
13
26
28
29
50
60
61
65
66
68
69
70
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1
1.
YNTRODUCTION
Chromium (Cr) is commonly known for its use as a decora-
tive finish in chrome plating.
Most of the chromium ore pro-
duced is used in the production of stainless and austenite steels.
However, chromium chemicals* appear to be more important than
chromium or chromium ore in relation to air pollution.
Chromium concentrations in the urban air average 0.015
~g/m3 and range as high as 0.350 ~g/m3.
Although the exact
sources of chromium air pollution are not known, some possible
sources are the metallurgical industry, chromate-producing
industry, chrome plating, the burning of coal, and the use of
chromium chemicals as fuel additives, corrosion inhibitors,
pigments, tanning agents, etc.
Industrial workers, especially
in the chromate-producing industry and chrome-plating works,
have been observed to develop a variety of health problems
attributed to chromium.
These problems include dermatitis,
ulcers on the skin and in the upper respiratory tract, per-
foration of the nasal septum, and cancer of the respiratory
tract.
*Chromium forms a series of compounds corresponding to
the oxidation states +2, +3, and +6. The chromous compounds,
in which the chromium exhibits the +2 oxidation state, are so
readily oxidized on standing in air or in aqueous solution
that they are seldom encountered. Chromic compounds are tri-
valent and amphoteric. The oxides, CraOs or crOa-, are referred
to as chromites, and the term chromite is easily confused with
chromite ore, FeOCraOs. Chromates, which are hexavalent, are
acidic. !hey are usually water solliQle and form the chromate
ion (CrO~-) or dichromate ion (Cra07-).
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2
2.
EFFECTS
The effects of chromium and its compounds on humans,
animals, plants, and materials depend upon the chemical state
of the chromium.
Chromium metal and trivalent chromium are
thought to be relatively nontoxic.IO
Hexavalent chromium may
produce a variety of effects.
Therefore, the chemical state
of chromium in the atmosphere is important.
The oxidation potentials of chromium and its compounds
indicate that trivalent chromium is most stable.
The chemical
potential favors oxidation of chromium metal and chromous ions
to the trivalent state, and reduction of hexavalent chromium
to the same state.
However, a thin oxide layer is believed to
protect the metallic chromium from further oxidation.IOO
Chromium trioxide (CrOs) is perhaps the most important
hexavalent chromium compound in the air.
When it is added to
water or acid, it forms chromic acid (HaCr04) or one of its
condensation products:
2HaCrO~ = HaCra07
+ HaO
3HaCr04 = HaCrS010
+ 2HaO
nH~Cr04 = HaCrnOsn+l + (n-I)HaO
The formation of the dichromate ion is instantaneous, while
the formation of the higher condensation products is slower.IOO
These hexavalent oxides are only variations in the hydration of
chromium trioxide (nCrOs.HaO), and it is common to express the
concentration of hexavalent chromium as CrOs.
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3
Chromite ore (FeOCr203)' usually impure, is very inert.
It is insoluble in water and acids and resists reactions with
most chemicals.lOl
Chromic(III) compounds, being amphoteric, are insoluble
in water but soluble in acids.lOO
However, chromic compounds
are readily complexed to form soluble coordination compounds.
Chromous(II) compounds are so easily oxidized that they
are not normally found in mammals.lO
The properties, toxicity, and uses of chromium compounds
are listed in Table 7 in the Appendix.
2.1
Effects on Humans
2.1.1
Chromium Metal and Trivalent Chromium
Until 19S6 it was believed that pure metallic chromium
was biologically inert and exerted no harmful effects on the
body.
Moreover, trivalent chromium was considered to exert
little or no harmful effects.
These conclusions were substan-
tiated by the failure at that time to produce toxic effects in
animalslO,7S and the failure to observe a higher morbidity
among workers in the chromium-manufacturing industry when com-
pared to other ferroalloy workers. IS
However, more recent
evidence indicates that at least the trivalent chromium can
produce harmful effects.
Sluis-Cremer and Du Toit91 report
that chrome-ore miners develop a benign pneumoconiosis after
inhaling chromite dust, but they find no evidence of fibrosis.
Worth and Schillerl04 indicate that bronchitis and emphysema
may occur in chromite workers.
There is mounting evidence
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4
that animals too may suffer toxic effects.
They have been
made hypersensitive to both chromium(III) and chromium(IV).
(See Section 2.2.2.)
Some instances of hypersensitivity in
humans to chrome-tanned leather have been described.34
More-
over, dermal sensitivity to trivalent chromium has been ob-
served in people who are epidermally sensitive to hexavalent
chromium. 22, 36
2.1.2
Chromates
In contrast to the trivalent compounds, the hexavalent
compounds are extremely irritative, corrosive, and toxic to
body tissues, and, under some circumstances, exert a carcino-
genic action on them.lO,37,73
The more potent effects of the chromate compounds have
been attributed by some investigators45,75,76,83 to the dif-
ferences in solubility of the chromium compounds.
Most chro-
mium(VI) compounds (except barium chromate and lead chromate)
are very soluble in water and body fluids, while chromium(III)
is soluble only in acid solution or when complexed with organic
or other ligands.
Chromite ore, on the other hand, is extremely
insoluble.
Pierce and Schee175 suggest that the toxicity of
chromium is a function of its solubility in protein solution.
In a subsequent study, Pierce and Stemrner76 showed that chro-
mium(III) reacted with human serum at the carboxylate groups.
The interaction was dependent on pH level of serum, concentra-
tion of chromium, and amount of time allowed for the reaction.
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5
It has been suggested that the highly soluble hexava-
lent compounds may penetrate some tissues before reacting with
the tissue.45,S3
Studies61,SO,Sl,S3 of the interaction of
chromates with skin indicate that the chromates are reduced
to trivalent chromium before binding with the skin.
Samitz
and his co-workersSO,Sl,S4 have been investigating ascorbic
acid as a means of chemically reducing the hexavalent chromium
and complexing the resulting trivalent chromium with the ascor-
bic acid.
In contrast to these studies, Mancuso and Hueper63 sug-
gest that insoluble chromium compounds may playa causal role
in the production of lung cancer because dust of insoluble
chromium compounds is retained over long periods of time in
the lungs.
Experimental studies were carried out in the U.S.S.R.23
with hexavalent chromate.
In this study 250 men were exposed
to 12 different chromium aerosols, ranging in concentration
from 1.5 to 40 ~g/m3.
Results indicated that inhalation of
air containing 10 to 24 ~g/m3 of chromium, even for a brief
period of time, elicited a sensation of sharp irritation of
the upper respiratory tract.
For the volunteers most sensi-
tive to the effects of chromium, 2.5 ~g/m3 of chromium repre-
sented the concentration of threshold perception: 1.5 ~g/m3
was below the perception threshold of the entire group.
At
these low levels (2.5 ~g/m3), eye sensitivity to light was
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6
enhanced and adaption to the dark was inhibited.
Rats also
indicated similar responses.
2.1.2.1
Respiratory Tract
One of the most common effects of inhalation of chro-
mate dust or chromic acid mist among chromite-producing indus-
trial workers and chrome-plating workers is the perforation of
the nasal septum.10,55
This characteristic lesion appears as
a painless hole.
Often ulcers exist on the nasal septum with-
out the subject's awareness of their presence.
Samitz and
Katz82 in their review of the literature cite Edmundson,29 who
reported that 61.4 percent (175 out of 285) of the male workers
in the production areas of a large chromate-producing plant
exhibited perforation of the nasal septum.
Hanslian et al.4l
examined 77 persons exposed to chromic acid mist during chrome
plating:
19.3 percent had perforation of the nasal septum;
47.7 percent had nasal mucosa irritation; 34.8 percent had
atrophy, of whom 9.0 percent had atrophy of the nasal skeleton;
34.8 percent had rhinitis sicca anterior; and 23.1 percent had
a lesion of the sensory epithelium.
Papillomas of the oral
cavity and larynx in 14 persons were found to contain 9.25 ~g
of chromium.
These workers were exposed an average of 6.6
years to a mist containing 4,000 ~g/m3 of chromium.
Other effects of chromates on the respiratory tract
include congestion and hyperemia, chronic catarrh, congestion
of the larynx, polyps in the upper respiratory tract, chronic
inflammation of the lung, emphysema, tracheitis, chronic
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7
bronchitis, chronic pharyngitis, bronchopneumonia, and cancer
of the respiratory tract.10
(Cancer is discussed in detail in
a following section.)
These effects were not all observed in
a u.s. Public Health Service examination of 897 chromate-
producing workers.37
The Public Health Service in 1953 reported
finding a high incidence of severely red throats and a frequent
history of pneumonia among these workers.
Mikov66 investigated
85 employees of a chrome-magnesite works and found 5 cases (5.9
percent) of early pneumoconiosis and 15 cases (18.8 percent) of
chronic bronchitis.
These workers were exposed to dust concen-
trations of 176,000 ~g/m3 (3.8 to 5.6 X 103 particles/cm3) con-
taining 4,500 to 9,200 ~g/m3 of chromium.
Chronic bronchitis
was observed only in workers with exposures longer than 5 years
and pneumoconiosis only in those exposed more than 9 years.
2.1.2.2
Skin
One of the important effects of chromates on individuals
is the development of hypersensitivity to these compounds with
a resulting dermatitis.10,37
This eczematoid dermatitis may
cause inflammation of intact skin, usually on the hands and
forearms, and occasionally on the feet, ankles, face, and back.
If the contact with chromates is severe enough, these reactions
will appear on normal healthy workers.
However, on a few
workers who are apparently hypersensitive to chromates, the
dermatitis appears to be an allergy.
The sensitization usually
requires 3 to 6 months to develop, but in some instances several
years of exposure have elapsed before sensitization.
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8
Cairns and Colman18 reported two cases of cement der-
matitis on individuals with "green tattoos."
Although chro-
mium(III) had been used in tattooing, both subjects were sen-
sitive to the chromate dust in the cement.
Newhouse72 tested
230 assemblers from an automobile factory with potassium dichro-
mate and found that 36 percent reacted compared with 7.6 percent
of 66 men in a control group.
The cause of the hypersensitivity
was traced to a chromate dip used on nuts, bolts, washers, and
screws used by the assemblers.
Similarly, Engel and Colman31
found that 65 of 250 workers engaged in wet sanding of primer
paint on car bodies developed dermatitis.
Investigation re-
vealed zinc chromate in the paint as the cause.
An engraving
foreman54 at a Washington, D.C..daily newspaper reported that
a worker became so sensitive to a residue of sodium dichromate
on engraving plates that he contracted a dermatitis.
The
sodium dichromate solution had been washed from the plates
before the worker handled them.
Unfortunately, none of these
studies indicates the concentration of chromates necessary to
cause dermatitis.
Nevertheless, it appears that even small
amounts of chromates in air may cause dermatitis in some hyper-
sensitive persons.
The hypersensitivity of individuals may be determined by
patch tests. 28
The suggested concentration of potassium dichro-
mate in the test solution is 0.1 to 0.5 percent.
A patient with
a strong hypersensitivity has reacted to a 0.005 percent potas-
sium dichromate solution and 0.0001 to 0.0004 percent potassium
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9
dichromate solution obtained as a filtrate solution extracted
from cement.
The original cement contained 0.03 to 6.9 ~g of
chromium(VI) per gram of cement; expressed as potassium dichro-
mate, this would be 0.08 to 20 ~g/g.
Epidermal hypersensitivity, as a result of industrial
contact with chromates, has occurred in workers in woolen mills;
automobile plants and garages; aircraft plants; locomotive main-
tenance shops; air-conditioning equipment maintenance shops;
plants that manufacture or use chromate compounds; and tanning,
photographic, and lithographic plants.l03
In addition to dermatitis, skin contamination with chro-
mates has been observed to produce ulcers--"chrome holes"--on
industrial workers.10,37,73
These ulcers have even on occasion
penetrated to the bone.
Over 50 percent of a group of chromate
workers showed signs of either active or healed chrome ulcers
( scar s) . 73
The ulcers appear most commonly on the hands, arms,
and feet or, in fact, in any area where dust can accumulate,
such as the knuckles and roots of the nails.
Once the ulcer
is formed, it is difficult to heal and, without proper treat-
ment, may persist for long periods of time.
2.1.3
Carcinoqenesis
Chromium compounds have been shown to produce cancer in
the respiratory tract, especially among workers in the chromate-
producing industry.9,10,16,62,63
The U.S. Public Health Ser-
vice37 reported in 1953 that the death rate due to cancer of
the respiratory tract of chromate workers was greater than 28
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10
times the expected death rate:
470.8 deaths/100,000 compared
with 16.7/100,000 males of the same age group in the United
States.
The large majority of cancers of the respiratory
tract were bronchogenic carcinomas, but a few cancers were
located in the upper respiratory tract, such as in the sinus,
pharynx, and oral region.
There is no evidence to suggest
that chromium causes cancer of any organs other than those of
the respiratory tract.
The time-concentration relationship between chromium
exposure and cancer induction is not known.
The average dura-
tion of exposure to chromium before death by cancer is 18
years.lO,37
The average time from initial exposure to the
diagnosis of cancer is 21 years.
The period between the onset
of symptoms and death is less than 6 months,
in some cases
only a few weeks.
Cancer that is apparently induced by chro-
mate exposure may develop years after the exposure has ceased.
Intervals of as long as 20 to 30 years between the end of expo-
sure and appearance of cancer are on record.
The concentration
of chromium in the inhaled air that is necessary to produce
lung cancer is not known.
In most cases, the concentration
was seldom measured, especially prior to 1940.
In aU. S.
Public Health Service study, the average chromium concentra-
tions were measured in six chr~mate-producing plants.
The
results of these surveys are summarized in Table 1.
The ore
processors were exposed primarily to chromite ore, the typical
composition of Which is given in Table 2.
Table 3 shows that
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11
TABLE 1
MEAN CHROMIUM EXPOSURES FOR WORKERS IN CHROMATE-PRODUCING PLANTS37
Occupational Groups
Chromium Exposure
Total Cr CrO~
(uq/m3 ) (UQ/m2 )
Ore processors
Soda ash-lime handlers
Mill room laborers
Mix operators (are)
Mix operators (residue)
Kiln operators
Kiln building laborers
Crane operators
Leach operators
Mud operators
Residue drier operators
Residue mill operators
Alumina recovery operators
Evaporator operators
Chemical treat operators
Sulfate recovery operators
Liquor concentration operators
Centrifuge operators
Soda drying-bagging operators
Shippers
Chromic acid cookers-packers
Potash production operators
Chromate operators
Tanning compound operators
420
210
160
770
390
210
230
260
190
50
160
390
130
30
120
280
60
200
110
160
30
170
30
460
10
10
30
20
130
90
90
130
120
50
60
50
50
20
50
110
40
130
100
20
20
170
30
10
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TABLE 2
TYPICAL COMPOSITION OF CHROMITE ORE37
Compound
Weiqht, percent
Cr20s
Fe2 Os
A120s
SiO:;!
MgO
CaO
Loss
on ignition
14.2
51.1
9.2
6.8
11.3
3.0
4.0
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13
TABLE 3
CHROMIUM IN BODY TISSUES10
(~g/lOOg wet tissue)
Origin
of Specimen
Range of Concentrations
in People
Without Known Exposure
to Chromium
Range of Concentratio~s
in
Chromate Workers
Abdominal lymph nodes 1 4- 80
Adrenal glands 0-41 5- 76
Aorta 3
Bile 1
Bladder 3- 226
Bone 5 0- 292
Brain 0- 4 0- 5
Bronchus 95- 386
Cartilage 6
Hair 31
Heart 0- 20
Intestines 10 4- 5
Kidney 0- 9.6 0- 211
Larynx 21
Liver 1-11 0- 159
Lungs 0-33 130-9,887
Lung tumor 0-1, 658
Metastatic tumo rs 2- 100
Muscle 0- 8 0- 19
Nasal septum 287
Pancreas 21 8- 36
Skin 5
Spleen 0-98 0- 91
Stomach 0- 5 4- 11
Thyroid 43 24- 53
Trachea 0- 32
Tracheobronchial lymph
nodes 0- 1 12-7,590
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14
chromate workers had accumulated appreciably higher concentra-
tions of chromium in the body than the general population.
However, examination of the lung tissues indicated that can-
cers were not always associated with the highest concentrations,
nor were the cancers found in the area of the lungs containing
the highest concentration of chromium.10
Undoubtedly, indivi-
dual susceptibility plays an important role in cancer induced
by chromium compounds.
Which chromium compounds can produce cancer is unknown.
However, since no cases of lung cancer have been reported among
chrome-ore minerslO or chromite workers, 37 it is generally pre-
sumed that cancer is induced by hexavalent compounds, chromates,
dichromates, or chromic acid.lO
Acid-soluble, water-insoluble
chromium compounds (probably trivalent) have also been suggested
as carcinogens.37
Animal experiments have also indicated that chromium com-
pounds are carcinogenic.
Hueper and payne45 state that the high
and early yield of tumors in mice implanted with chromium com-
pounds leaves no doubt that chromium is a carcinogenic agent.
Moreover, solubility plays an important role in the production
of tumors.
Calcium chromate, which has a high solubility, pro-
duced a high incidence of tumors, whereas barium chromate, which
has a low solubility, produced a very low incidence of tumors
after a long period of observation.46
2.1.4
Nutrition
Recently, chromium has been found to be an essential
-------
15
element in the diet of rats, which infers that it may be essen-
tia1 to man.65,85,86
Chromium deficiency in rats produces a
syndrome that simulates diabetes:
the normal glucose metabo-
1ism is inhibited.85
Mertz65 believes that chromium is an
essential trace element for the normal function of carbohy-
drate metabolism.
Schroeder et al.86 have shown that chromium
exists in all human tissue and is highest at the time of birth
(Table 8, Appendix).
The chromium content then decreases to
a lower plateau.
Only the chromium content in the lungs is
observed to increase again significantly.
Because of the
ubiquitous nature of chromium, it has not been possible to
find a group of people without chromium in their diet.
2.2
Effects on Animals
2.2.1
Commercial and Domestic Animals
No cases of animal poisoning due to airborne chromium
were found in the literature. However, chromite (Cra03) has
been used as an additive in feed for pigs,lO dogS,lO and beef
cattle77 to study the digestion of certain foods.
In these
studies approximately 100 percent of chromite (Cra03) was
recovered unchanged in the feces.
2.2.2
Experimental Animals
A number of animal experiments have been conducted.
The early experiments were summarized by BaetjerlO and are
listed in Table 9 in the Appendix.
There is evidence that
animals can be made hypersensitive to both chromium(III) and
chromiurn(IV).
Gross, Katz, and Samitz39 produced hypersen-
-------
16
sitive reactions in guinea pigs with potassium dichromate(VI)
and chromic(III) chloride.
They observed cross-reactions with
chromic acetate, chromic nitrate, and chromic sulfate, and no reac-
tion with chromic oxalate.
Jansen and Berrens.50
Similar results were obtained by
Hueper and payne45 have shown that cancer can be pro-
duced in experimental animals by implantation.
However, Baetjer
and her co-workers11,l2,92 have been unable in several attempts
to produce more than a benign tumor in the lungs of mice and
rats inhaling various chromium-containing dusts.
2.3
Effects on Plants
Chromium has been observed both to stimulate plant
growth and to be toxic to plants.
The effect depends largely
on plant type, chromium concentration in the soil, and more
importantly, availability of the chromium to plants.
In soils
less acidic than pH 4 very little chromium is available to
plants.
When small amounts (0.01 percent) of chromium are
available, the growth of oats and barley is stimulated.
How-
ever,
even a smaller amount (0.005 percent) is toxic to wheat.
Toxic effects may be expected in plants when the levels of
available chromium in the soil exceed 10-7 ~g/g of soil.lOO
Nevertheless, some plants may tolerate as much as 100,000
~g/g.
No evidence of plant damage by airborne chromium was
found in the literature.
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17
2.4
Effects on Materials
Chromic acid is not only a strong acid but also a strong
oxidizing agent.
Therefore, it will cause corrosion of metals,
discoloration of paints and building materials, and damage to
paper and textiles.
For example, damage to paints and building
materials caused by the evolution of chromic acid mists from
plating operations has been observed.lO
The exposure of auto finishes to chromic acid mists in
Detroit resulted in brown stains on light-colored cars and a
blushing on darker shades of paint.
Repainting was required
because the color change in the paint could not be corrected
by washing or polishing.l05
2.5
Environmental Air Standards
The American Conference of Governmental Industrial
Hygienists97 and the American Industrial Hygiene Association8,20
have recommended an 8-hour tolerance level of 100 ~g/m3 for
chromic acid and chromates (as CrOs).
This is a reduction from
a value of 1,000 ~g/m3 of chromate (as CrOs)' recommended in
1943 by the American Standard Association.8
In the U.S.S.R. a value for chromates (as CrOs) of 1.5
~g/m3 has been recommended as both the maximum permissible
single dose and the maximum permissible average daily concen-
tration.23,52,56,79,94
The U.S.S.R. has also recommended as
maximum allowable concentrations for trivalent chromium and
its compounds (as Cr20s)
250 ~g/m3 for a single exposure and
80 ~g/m3 for an average 24-hour exposure. 51
-------
18
3.
SOURCES
The pollution of air by chromium and its compounds comes
primarily from industrial use and end-product use.
There has
been no mining of chromite ore in the United States since 1961
because higher-grade ore can be purchased from foreign coun-
tries at a cheaper price.69
Approximately 57 percent of the
imported chromite ore (FeOCr20s) is used in the metallurgical
industry, 30 percent in refractory materials, and 13 percent
in the chemical industry (see Table 10, Appendix).
3.1
Natural Occurrence
Elemental chromium is not found in nature.
The only
important commercial chromium mineral is chromite (FeOCr20s)'
which is also never found in the pure form.
(Some of the FeO
is replaced with MgO or the Cr20s is replaced by A120s.
Silica
is also present.)
Most soils and rocks contain small amounts
of chromium, usually as chromic oxide (Cr20s)'
The continental
crust averages 0.037 percent by weight of chromium.
In addition,
most animal and plant tissues contain small amounts of chromium.
Soils have been observed to contain from a trace to 2.4
percent chromium.
Vegetables of 25 botanical families were
found to contain 10 to 1,000 ~g of chromium per kilogram of
dry matter, with most plants falling within the range of 100
to 500 ~g/kg.
As stated above, chromite is no longer mined in this
country.
However, low-grade ore deposits do occur in Cali-
fornia, Montana, Oregon, and Alaska.67
-------
19
3.2
Production Sources
3.2.1
Metallurqical Industrv
Use of chromite ore in the metallurgical industries is
almost all confined to chrome alloys or chromium metal.
The
U.S. consumers of chrome ore are listed in Table 11 in the
Appendix.
The metallurgical chromite is usually converted
into one of several types of ferrochromium or chromium metal
that are alloyed with iron or other elements (usually nickel
and cobalt).
From these alloys are produced a great variety
of useful steels.
Over 60 percent of the chromium used in the
metallurgical industry is used in making stainless steel; the
remainder is used in austenite steels, high-speed steels,
other alloy steels, high-temperature steels, and nonferrous
11 21,43
a oys.
Chromium compounds polluting the air from metal-
lurgical uses are likely to be in the trivalent or zero state.
3.2.2
Refractory Materials
Chromite ore is used in the manufacture of refractory
bricks to line the inside of metallurgical furnaces because
chromite has a high melting point (3,700oF) and is chemically
inert.
In addition to their use as chromite bricks or magnesia-
chrome bricks, chrome refractory materials may be used as
coatings to close pores and for joining bricks within the fur-
101
nace.
Studies of chromium air pollution from this source
have not been found.
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20
3.3
Prod uct Sourc es
3.3.1
Chemical Industry
Sodium chromate and dichromate are produced directly
from the chromite ore, and are the primary products from which
other chromium compounds are manufactured.
Table 12 in the
Appendix lists the production of chromium chemicals in the
United States.
Basically, the manufacturing process for chro-
mate chemicals is the same in all plants.
Briefly, it consists
of roasting the finely ground chromite ore with soda ash or
with soda ash and lime.
A water-soluble chromate, sodium chro-
mate, is formed and is then converted by acidification into
crystalline sodium dichromate (see Figure 1, Appendix):
2Cr2 Os + 4Na2 COs + 302
) 4Na2Cr04 + 4C02
37
Gafafe~ et El. report a study in which the dust con-
tent of air in six chromate-producing plants was measured.
The data show that trivalent chromium dusts are emitted from
dry ores at the start of the process, and, after the chromite
has been oxidized to chromate, chromate dusts are emitted
throughout the remainder of the process (see Table 1, Page 11).
The average dust content inside the six plants was 170 ~g/m3
of chromium(VI).
No data were reported on concentration mea-
surements of chromium outside the plants, but the concentration
was thought to be much lower.
However, analysis of samples
-------
21
from a comparison paper plant, which was located only one-
quarter mile from a chromate-producing plant, showed the pre-
sence of chromium in the settled dust.
The authors comment
that the contamination must have come from the chromate-
producing plant.
Several dust-controlled working areas in
which the dust was exhausted from the plant were mentioned,
but no mention of dust-control equipment on the exhaust system
was made.
Air samples at the mouth of some of these exhaust
systems ranged as high as 148,000 ~g/m3 of chromate.
From
these data it may be concluded that chromate-producing plants
can be a source of chromium air pollution.37
A substantial amount of chromium chemicals, estimated
in 1956 at 2.8 million pounds of dichromate equivalent, are
used in the manufacture of catalysts.13,14,21,32,38,44,57,93,98
Chromates are used for the oxidation of organic materials
in production of synthetic dyes, saccharin, benzoic acid, anthra-
quinone, hydraquinone, camphor; and synthetic fibers.
The oxi-
dizing properties of chromates have led to their wide use as
cleaning agents, in the purification of chemicals, and in inor-
ganic oxidation.
3.3.2
Chrome Platinq
A major percentage of the chromic acid that is consumed
is used for chrome plating.
This plating may be a decorative
-------
22
finish or "hard" plating.
The hydrogen bubbles that evolve
from the electrolytic solution carry with them an aerosol of
chromic acid.
It is now common practice to exhaust these
fumes to the atmosphere.17
Small chrome-plating facilities
are almost a neighborhood occurrence.
3.3.3
Other Uses
Chrome-tanninq industries use more than 15 million
pounds of chromic oxide (Cr20s) annually.
The chrome-tanning
solution, containing chromium(III) sulfate
«Cr(H20)sOH)S04)'
is made from sodium dichromate and may be prepared in a chemi-
cal plant or at the tannery.21,37,lOO
Primer paints and dips contain chromates and are used
to prepare metal surfaces for painting.
Automobile parts are
usually dipped in the solution, whereas construction steels
are normally sprayed.2l,32,lOO
Piqments consume approximately 30,000 tons of sodium
dichromate per year.
Chromates and chromic oxide are combined
with various other metals such as zinc, lead, iron, barium,
100
molybdenum, and strontium to produce a variety of colors.
Chromium mordants find a diversified usage in the tex-
. d t 100
tile ~n us rYe
Graphic arts industries use approximately 200,000 pounds
of dichromates.
A photosensitive dichromate-colloid suspension
-------
23
is used in preparing plates in many printing and reproducing
processes.21
Funqicides and wood preservatives consume approximately
2.9 million pounds of chromium chemicals annually.
The major
fungicide use is for potato and tomato blight control, seed
sterilization, and lawn fungicide control.
The use of chro-
mate wood preservatives in wooden cooling towers may be of
particular interest in relation to air pOllution.21,100
Chromate chemicals are used widely in cooling-tower
recirculating water systems as rust inhibitors as well as
wood preservatives.
The most favored inhibitors are sodium
chromate and complex chromate salts.95
Such systems continu-
ously discharge about I percent of their flow to waste (blow-
down to waste water), and some water is lost to the atmosphere.
Fresh water and chromate are then added to replace the lost
water and chromate.
The circulating water usually contains 15
to 300 ppm chromate ion.
The lower concentrations are more
common because synergistic ingredients are frequently used with
chromates now.
Corrosion inhibitors for a variety of applications con-
tain chromates.
Soluble chromates are effective inhibitors
for the corrosion of iron, steel, zinc, aluminum, copper, brass,
lead, and related alloys.
These inhibitors have found practical
-------
24
use in cooling towers (mentioned above), air conditioning
equipment, automobile radiators, diesel locomotives,
marine
diesels, stationary diesels, refrigerating brines, ammonia
condensers, ammonia absorption systems, stand-by boilers,
operating boilers, steam-heating boilers, hot-water heating,
salt for melting ice and snow, oil-well-drilling mud, gaso-
line pipelines, industrial coolers, hydroblasting make-up
water, and hydraulic lifts.lOO
Paper matches contain a small amount of potassium di-
chromate as a burning-rate catalyst.
Approximately 400 billion
"lights" are manufactured per year. 21
Fireworks contain some chromium chemicals.lOO
Gasoline antiknock chromium compounds have been tested,
but have not been used because of deposition in the engine.2l
However, antistatic additives produced by the Shell Oil Com-
pany contain a chromium salt of alkylated salicylic acid.
They are recommended for use in aviation or ather fuels.60
Dry-cell batteries contain a small amount of lithium
chromate. 87
3.4
Other Sources
3.4.1
Asbestos
Some investigators24,25,27,40,42 have suggested that
the small amounts of chromium or other trace substances found
-------
25
in asbestos may be the cause of cancer associated with asbestos.
The chromium concentration found in the most common asbestos
mineral, chrysolite, was approximately 1,500 ~g/g.25
3.4.2
Coal
The concentration of chromium in coal ranges from 7 to
20 ~g/g, and the ash contains 1 to 270 ~g/g, depending on the
origin of the coal. I
The chromium emissions of six different
types of coal-fired power plants are given in Table 4.
3.4.3
Cement
Cement contains chromium28 sufficient to cause a der-
mati tis in some hypersensitive people when they come in con-
tact with it.17
Keenan and perone53
have shown that cement
contains 0.03 to 7.8 ~g of chromium(Vr) per gram of cement and
28 to 60 ~g of total chromium per gram, depending on the ori-
gin of the cement (see Table 13, Appendix).
Chromates are
thought to be produced during the kiln processing in the manu-
facture of cements.
The fact that chromates are produced in the heat treating
of chromic oxide (Cr203) under alkaline conditions--as in the
production of both chromate and cement--raises the question of
production of chromates in other materials, e.g., asbestos.
3.4.4
Weldinq Rods
Fregert and Ovrum35 and shelley88 have found hexava-
lent chromium in welding-rod fumes.
-------
TABLE 4
26
CHROMIUM EMISSIONS FROM COAL-FIRED POWER PLANTS
Flue Gas Chromium Emissions
Coal Ash in Volume, 3
Type of Rate Coal (as scfm x 103 uq/m q /min q /ton
IBoiler Firinq ton/hr fired) % B A B A B A B A
Vertical 65.6 20.2 397.4 409.9 220 18 2.5 0.21 2.3 0.19
Corner 56.1 14.9 362.9 351.0 1,900 130 19 1.3 20 1.4
Front-wall 52.2 10.3 329 . 0 3 28 . 0 1,100 160 10 1.5 11 1.7
Spreader-stoker 9.2 8.4 53.9 59.6 450 350 .069 .059 .45 .39
Cyclone 64.4 7.7 553.6 500.8 1,900 500 30 7.1 31 6.6
Horizontally 9.6 8.2 62.2 62.2 2,200 410 3.9 .72 24 4.5
opposed
A:
After fly ash collection.
B:
Before fly ash collection.
N
0'\
-------
27
3.5
Environmental Air Concentrations
Air quality data obtained from the National Air Sampling
Network are shown in Table 14 in the Appendix.
The national
average concentration of chromium in 1964 was 0.015 ~g/m3 and
the national maximum was 0.350 ~g/m3.2,4-6
Schroeder ~ al.86 investigated the chromium content of
the kidneys, livers, lungs, and hearts of people living in
various parts of the country.
Their data, shown in Table 5,
indicate that the environmental exposure to chromium varied
significantly.
Similar findings were obtained by Tipton and
Shafer,99 who concluded that lungs of subjects from Baltimore
have significantly higher chromium concentrations than those
from Dallas, Denver, Miami, and San Francisco.
Lee et sl.58,59 have measured the particle-size distri-
bution of chromium in ambient air.
These data are presented
in Table 6.
-------
28
TABLE 5
86
CHROMIUM CONCENTRATION IN HUMAN TISSUES BY CITY, U.S.
(~g/g)
City Kidney Liver Lunq Heart
Baltimore .06 .038 .41 .03
Dallas .022 .023 .11 .021
Denver .04 .03 .14 .03
Miami .015 .012 .14 .014
New York and Chicago .09 .27 .72 .13
Richmond, Va. .033 .024 .24 .051
Seattle and Tacoma .029 .026 .34 .04
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29
TABLE 6
PARTICLE SIZE OF CHROMIUM PARTICULATES IN THE AMBIENT AIR 58, 59
Concentration Mass Median
(j.lq/m3 ) Diameter (u)
maximin maximin
max min avq ratio max min avq ratio
Cincinnatia 0.91 <0.01 0.16 >91.0 >10 <0.1 1.7 >100
Cincinnatib 0.31 1.5
Fairfaxc 0.28 1.9
Ind ian Creekd 0.39 <0.01 0.11 >39 >10 <0.1 2.0 >100
a
Samples collected in downtown Cincinnati, Ohio, May 24-
June 3, 1967.
bsamp1es collected in downtown Cincinnati, Ohio, Sept. 8-23, 1966.
csamp1es collected in Fairfax, Ohio, a suburb of Cincinnati, Ohio,
Feb. 3-16, 1967.
dsamp1es collected at the Indian Creek Wild Life Preserve, Ohio,
May 24-June 3, 1967.
-------
30
4.
ABATEMENT
Chromium air pollution usually occurs as particulate
emissions, which may be controlled by the usual dust-handling
equipment, such as bag filters, precipitators, and scrubbers.
Chromium poses no peculiar control problems except when it is
emitted as aerosols (e.g., sprays and chromic acid mists).
Some chrome-plating facilities have installed methods
of preventing air pollution.
Moisture-extractor vanes in the
hood-duct system have been used to break up bubbles in the
exhaust gases.lOI
Most exhaust systems use slot hoods to cap-
ture the mists discharged from the plating solutions.
The
device most commonly used to remove air contaminants from
exhaust gases in the hard-chrome-plating facilities is a wet
collector.
The scrubber water becomes contaminated with the
acid: therefore, efficient mist eliminators must be used in
the scrubber to prevent a contaminated mist from being dis-
charged to the atmosphere.
The mist emissions from a decorative-chrome-plating tank
with lesser mist problems can be substantially eliminated by
adding a suitable surface-active agent to the plating solutions.
The action of the surface-active agent reduces the surface ten-
sion, which in turn reduces the size of the hydrogen bubbles.
Several of these mist inhibitors are commercially available.
-------
31
In a new plating facility, there will be an attempt to
replace the hood system with a coating of synthetic material
that will float on the electrolyte.
The coating is expected
to suppress the chromic acid mist to prevent it from leaving
the bath.19
-------
32
5.
ECONOMICS
No information has been found on the economic costs of
chromium air pollution or on the costs of its abatement.
How-
ever, chromic acid mists have caused some material damage to
building and auto paints (see Section 2.4).
Data on the production and consumption of chromium are
presented in Section 3.
-------
33
6.
METHODS OF ANALYSIS
6.1
Samplinq Methods
Dusts and fumes of chromium compounds may be collected
by any method suitable for collection of other dusts and fumes;
the impinger, electrostatic precipitator, and filters are com-
monly used.
The National Air Sampling Network uses a high-
volume filtration sampler.96
Chromic acid mists may be col-
lected in an impinger using water or caustic solutions.102
6.2
Quantitative Methods
Emission spectroscopy has been used by the National Air
Pollution Control Administration for chromium analysis of sam-
pIes from the National Air Sampling Network.3,96
The samples
are ashed and extracted to eliminate interfering elements.
The minimum detectable chromium concentration by emission
spectroscopy is 0.0064 ~g/m3 for urban samples and 0.002 ~g/m3
for nonurban samples.
The different sensitivities result from
different extraction procedures required for urban samples.7
Thompson et al.96 have reported that the National Air
Pollution Control Administration uses atomic absorption to
supplement results obtained by emission spectroscopy.
The
method has a minimum detectable limit of 0.002 ~g/m3 based on
a 2,000 m3 air sample.
Westl02 indicates that the ring oven technique for the
-------
34
determination of chromium is sensitive to 0.15 ~g and has a
normal range of 0.3 to 1.0 ~g.
The chromium is oxidized to
the hexavalent state, and the method, therefore, measures
total chromium.
Diphenylcarbazide is used as the indicator.
A multichannel flame spectrometer has been used by Iida
and Fuwa47,48 to measure magnesium, calcium, copper, manganese,
and chromium simultaneously in biological materials.
Their
initial work indicated a sensitivity of 1.0 ~g/ml; however,
phosphates seriously interfered with the application of the
analysis.47
In subsequent studies,48 they added 8-hydroxy-
quinoline and perchloric acid, which not only eliminated the
interference, but increased the sensitivity of the test to
two of the elements, calcium and manganese (0.1 ~g/ml).
The concentration of chromic acid mists in air can be
estimated by a direct field method described by Ege and
Silverman. 30,89, 90
This is a spot-test method using phthalic
anhydride and S-diphenylcarbazide.
A coulometric method for determination of chromium in
biological materials is described by Feldman et al.33
The
method is sensitive to 0.2 ~g of chromium.
Pierce and Cholak74 have described an atomic absorption
method for the determination of chromium in biological systems.
The sample must be ashed.
The method is sensitive to 0.1 ~g of
chromium or 0.05 ~g/g.
-------
35
The Mine Safety Appliances Co.70,7l has a lightweight
sampler for estimating quickly the chromic acid mist concen-
trations in the atmosphere.
The operating principle of this
instrument is based on the method described above by Ege and
Silverman.30,89,90
-------
36
7.
SUMMARY AND CONCLUSIONS
The exposure of industrial workers to airborne chromium
compounds and chromic acid mists, particularly the hexavalent
chromates, has been observed to produce irritation of the skin
and respiratory tract, dermatitis, perforation of the nasal
septum, ulcers, and cancer of the respiratory tract.
~r~i~
metal is thought to be nontoxic.
Hexavalent compounds appear
to be much more harmful than trivalent compounds, with the
toxic effects depending on solubility.
Two effects that appear
to be particularly important in relation to air pollution are
hypersensitivity to chromium compounds and induction of can-
cers in the respiratory tract.
Exposure of industrial workers
in the chromate-producing industry has shown an incidence of
deaths from cancer of the respiratory tract which is over 28
times greater than expected.
Time-concentration relationships
for induction of cancer are not known.
No evidence of damage by airborne chromium to animals
or plants has been found.
Chromic acid mists have discolored
paints and building materials.
In 1964, atmospheric concentrations of total chromium
averaged 0.015 ~g/m3 and ranged as high as 0.350 ~g/m3.
Although the exact sources of chromium air pollution are not
known some possible sources are the metallurgical, refractory,
-------
37
and chemical industries that consume chromite ore; chemicals
and paints containing chromium; and cement and asbestos dust.
Particulate control methods should be adequate for chromium-
containing particles.
No information
has been found on the economic costs of
chromium air pollution or on the costs of its abatement.
Methods of analysis are available to determine the amount of
chromium concentration in the ambient air.
Based on the material presented in this report, further
studies are suggested in the following areas:
( 1 )
Resolution of the question of toxicity, hypersen-
sitivity, and cancer induction with relation to the valence of
chromium and solubility of chromium compounds.
( 2 )
Determination of the concentration and time of
exposure of chromium required to produce cancer.
( 3 )
Determination of the concentration and time of
exposure of chromium required to produce allergenic reactions
in hypersensitive people of the general public.
(4)
Determination of the concentration and valence of
chromium adjacent to chrome steel plants, refractory fabricating
plants, chromate-producing plants, chrome-plating operations,
spray-painting operations, cement-making operations, etc.
-------
10.
11.
38
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1.
Abernethy R. F_, and F. H. Gibson, Rare Elements in
Coal, u.s. Bur. Mines Inform. Circ. IC-B163 (1963).
2.
Air Pollution Measurements of the National Air Sampling
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3.
Air Pollution Measurements of the National Air Sampling
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4.
Air Pollution Measurements of the National Air Sampling
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Air Quality Data, 1962, National Air Sampling Network,
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Air Quality Data from the National Air Sampling Networks
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Air Quality Data from the National Air Sampling Networks
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Allowable Concentrations of Chromic Acid and Chromates,
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Baetjer, A. M., "Relation of Chromium to Health," Chapter
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Baetjer, A. M., J. F. Lowney, H. Steffee, and J. Buda~z,
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Literature on Air Pollution and Related Occupational
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Bidstrup, P. L., and R. A. M. Case, Carcinoma of the L'~g
in Workmen in the Bichromates-Producing Industry in Great
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Byers, D., Bureau of Occupational Health, U.S. Dept. of
Health, Education, and Welfare, Cincinnati, Ohio, personal
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47
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-------
APPENDIX
-------
Ore Processing (Crush, Dry, Mill)
( Oxidize to Chromate)
Leaching ( Water - Soluble Chromate Removed)
Neutralizing ( Alumina -Filtered Out)
and Treating Na Cr 0 Formed
2 2 7
Concentrating' Na Cr 0 Concentrated
227
by _Evaporation and Cooling)
Filtering, Drying & Packing (Bichromate Filtered,
Dried and Packed)
FIGURE 1
21
Typical Flow Diagram of Chromate-Producing Plant
49
Residue
Reprocessed
-------
APPENDIX
'fABLE 7.
64
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS
i-Qnmp0 und
Chromium trioxide
Cr03
Chromic acetate
Cdi:::.,: H3 0:.] )3
Chromic bromide
CrBr3
Properties
mp 197°C
Decomposes at
25 aOc
Slightly solu-
ble 1n water.
Practically
insoluble in
alcohol
Soluble in
boiling water
Sublimes
Toxicitv
Dermal contact can cause
primary irritation and ul-
ceration as well as al-
lergic eczema. Inhalation
can cause nasal irrita-
tion, septal perforation.
Pulmonary irritation,
bronchogenic carcinoma
may result from breathing
chromat~ dust. Ingestion
causes violent gastroin-
testinal irrita~ion with
vomiting, diarrhea. Re-
nal injury has been re-
ported in experimental
animals
Uses
In chromium plating, copper strip-
ping, aluminum anodizing7 as cor-
rosion inhibitor7 1n photography,
purifying oils and acetylene,
hardening microscopical prepara-
tions. Med. and vet. use: 5% so-
lution as topical antiseptic and
astringent. 2~1o solution as caus-
tic
As a mordant in dyeing; inldnrll.ng;!
in hardening photographic emul- !
sions; to improve light stability
and dye affinity of textiles and
polymers; in catalyst for poly-
merization of olefins
In catalysts for polymerization of
olefins
(continued)
U1
a
-------
APPENDIX
TABLE 7.
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Compound
Chromic carbonate
Cr203.xC02.yH20
Chromic chloride
CrC13
Chromic fluoride
CrF3
Chromic formate
Cr (HCOO) 3
Properties
A basic car-
bonate of in-
definite
composition.
Blue-gray a-
morphous pow-
der
Sublimes at
9500C
o
mp >1, 000 C
bp >l,lOOoC
Decomposes
above 3000C
Toxicitv
Keep tightly closed. MLD
iv in mice 801,000 ~g/kg
See chromium trioxide
See chromium trioxide
Uses
In preparation of chromic salts
In chromizing; in manufacture of
Cr metal and compounds; as cata-
lyst for polymerization of olefins
and other organic reactions; as
textile mordant; in tanning; ln
corrosion inhibitors; as water-
proofing agent
The hydrates are used in printing
and dyeing woolens, coloring and
hardening marble, mothproofing
woolen fabrics, treating silk,
polishing metals, and as halo-
genation catalyst
In printing cotton skeins; in lea-
ther tanning and waterproofing
(continued)
lJ1
I--'
-------
APPENDIX
TABLE 7.
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Compound Properties Toxicitv Uses
Chromic hydroxide Practically As pigment, e.g., Guignet 's green;
Cr ( OH ) 3 insoluble ln in tanning industry, as mordant; as
water catalyst for organic reactions
Chromic nitrate Decomposes In preparation of Cr catalyst; in
Cr(N03)3 above 600C textile printing; as corrosion
inhibitor
Chromic oxide mp 2,4 3 5 (J)C In abrasives; as refractory mater i-
Cr203 bp ",3,OOOoC als, electric semiconductors; as
pigment, particularly in coloring
glass; in alloys, printing fabrics
and banknotes; as catalyst for or-
ganic and inorganic reactions
"
Chromic phosphate Does not melt As green pigment; in wash primers;
CrP04 by 1,800oC in catalysts for dehydrogenation
of hydrocarbons and pOlYmerization
of olefins
Chromic potassium Freely soluble In tanning industry; in dyeing
oxalate in water chromate colors on wool
K3 [Cr(C204 bJ
(continued)
U1
I\J
-------
APPENDIX
TABLE 7.
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Compound
Chromic potassium
sulfate
KCr(S04)2
Chromic sulfate
Cr 2 (S04 ) 3
Chromite
FeCr:a04
Chromium carbonyl
Cr(CO)6
Properties
mp 890C
Peach-colored
solid. Prac-
tically in-
soluble in
water am
acid s
Sinters at
90oC. Decom-
pos es at l300C
Explod es at
2l0oC. Sub-
limes at room
temperature
Toxicitv
MLD iv ln mlce 247,000
I-lg/kg
LD50 iv in mice 100,000
I-lg/kg
Uses
As mordant for dyeing fabrics uni-
formly; in tanning leather,
printing calico; for rendering glue
and gum insol; ln manufacture of
ink, other chromium salts; for wa-
terproofing fabrics, hardening
photographic emulsions
For insolubilization of gelatin; in
catalyst preparation; as mordant in
textile industry; in tanning of
leather; in chrome plating; in
manufacture of Cr, Cr03' and Cr al-
loys; to improve dispersibility of
vinyl polymers in water; in manu-
facture of green varnishes, paints,
inks, glazes for porcelain
As only important commercial ore
In catalysts for olefin polymeri-
zation and isomerization; as gaso-
line additive to increase octane
number; in preparation of chromous
oxid e, CrO
(continued)
01
W
-------
APPENDIX
TABLE 7.
ComDound
Chromium
Cr
Chromium
tetrafluoride
CrF4
Chromous acetate
Cr{CaH302)2
Chromous bromide
CrBr2
Chromous chloride
CrC12
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Properties
mp 1,900oC
bp 2,480oC
mp 2000C
bp 400°C
Slightly solu-
ble in cold
water; readily
soluble in hot
water
o
mp 842 C
mp 8240C
Toxicity
Uses
See chromium trioxide
In manufacture of chrome-steel or
chrome-nickel-steel alloys (stain-
less steel); for greatly increasing
resistance and durability of metals;
for chrome plating of other metals.
d 51C' . d
The man-ma .e r ~sotope 1S use.
as tracer in various blood diseases
and in determination of blood vol-
ume (as the chloride or as Na
chromate)
A strong irritant
See chromium trioxide
In preparation of other chromous
salts; as 02 absorber in gas analy-
ses
In chromizing
See chromium trioxide
In chromizing; in preparation of Cr
metal; ln catalysts for organic re-
actions; as 02 absorbent; in analy-
sis
(continued)
U1
ol::>
-------
APPENDIX
TABLE 7.
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Compound Propertie s Toxicity Uses
Chromous fluoride mp 1,lOOoC A strong irritant In chromizing~ in catalytic crack-
CrF2 bp above See chromium trioxide ing of hydrocarbons~ as alkylation
1,300oC catalyst~ in nuclear reaction fuels
Chromous formate Soluble ln wa- In baths for Cr electroplating~ ln
Cr(HCOO)2 ter catalysts for organic reactions
Chromous oxalate
CrC204
Chromous sulfate Soluble in As analytical reagent~ for absorp-
CrS04 water tion of 02 from gas mixt ur es ~ as
dehydrohalogenating and red uc ing
agent
Chromyl chloride mp -96.SoC Burns and blisters the As catalyst for polymerization of
Cr02 C12 bp l170C skin. Handle only in olefins ~ in oxidation of hydrocar-
well-ventilated hood bons, ln Etard reaction for pro-
duction of aldehydes and ketones~
in preparation of various coordina-
tion complexes of Cr
Chromyl fluoride Sublimes at See chromium trioxide As fluorination catalyst~ to In-
Cr02F2 29.6oC crease olefin-polymer receptivity
mp 3l.6oC for dyes
(continued)
U1
U1
-------
APPENDIX
TABLE 7. PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Compound
Properties
Toxicity
Uses
Lead chromate
(chrome yellow)
PbCrO4
mp 844°C
LD50 ip in guinea pigs
400,000 |jgAg
As pigment in oil and water colors;
in printing fabrics, decorating
china and porcelain; in chemical
analysis of organic substances.
Basic lead chromates of colors from
brown-yellow to red are used as
pigments
Potassium
chromate(VI)
K2Cr04
mp 975°C
See chromium trioxide
LD sc in rabbits 12,000
1-igAg
Has a limited application in ena-
mels, finishing leather, rust-
proofing of metals, being replaced
by the sodium salt; as a reagent in
analytical chemistry
Potassium
dichromate(VI
K3Cr2O7
mp 398UC
Decomposes at
~500°C
Internally, a corrosive
poison—30 g reported fa-
tal within 35 min. Indus-
trial contact may result
in ulceration of hands,
destruction of mucous mem-
branes, and perforation of
nasal septum. Chromates
have been reported as
causing cancer of the lung
In tanning leather, dyeing, paint-
ing, decorating porcelain, printing,
photolithography, pigment prints,
staining wood, pyrotechnics, safe-
ty matches; for bleaching palm oil,
wax, and sponges; in waterproofing
fabrics; as an oxidizer in the
manufacture of organic chemicals;
in electric batteries; as a depo-
larizer for dry cells. As corrosion
inhibitor in preference to sodium
dichromate where lower solubility
is advantageous. Med. use: ex-
ternally as astringent, antiseptic,
caustic. Vet. use: as caustic for
superficial growths
(continued)
Ul
-------
APPENDIX
TABLE 7.
Compound
Sodium
chromate(VI)
Na2Cr04.4H20
Sodium
dichromate(VI)
Na2Cr207.2H20
Ammonium
dichromate(VI)
(NH4 )2Cr207
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Properties
o
mp 20 C
Anhydrous salt
mp 356.7oC
Decomposes at
~180oC
Flammable
Toxicitv
LD sc in rabbits 243,000
~g/kg
Irritant and
skin, mucous
See chromium
caustic to
membranes.
trioxide
Causes skin irritation,
ulceration, "chrome sores,"
perforation of nasal sep-
tum, pulmonary irritation
Uses
In protecting iron against cor-
rosion and rusting
As oxidizing agent in manufacture
of dyes, many other synthetic or-
ganic chemicals, inks, etc.; in
chrome-tanning of hides; in elec-
tric batteries; in bleaching fats,
oils, resins, sponges; ln refining
petroleum; in manufacture of chro-
mic acid, other chromates, and
chrome pigments~ in corrosion inhi-
bitors, corrosion-inhibiting
paints~ in many metal treatments;
in electroengraving of copper; as
mordant in dyeing; for hardening
gelatin; for defoliation of cotton
plants and other plants and shrubs.
Med. use: ln solution as anti-
septic, astringent, caustic
As source of pure nitrogen, es-
pecially ln the laboratory; in
pyrotechnics (Vesuvius fire); ln
lithography and photoengraving~ ln
special mordants, catalysts, and
porcelain finishes
(continued)
Ul
-..J
-------
APPENDIX
TABLE 7.
Compound
Ammonium chromic
i sulfate
; NH4, Cr (S04, ) a
Zinc dichromate
ZnCra073HaO
Ferric
chromate(VI)
Fea (Cr04, ) 3
Cupric chromate(III)
CuCra°4,
Cupic chromate(VI)
CuCr04
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Properties
Toxicity
Uses
mp 94°C
As mordant in textile industry; in
manufacture of electrolytic Cr
metal
Orange-yellow
powder. Insolu-
ble in water
Practically in-
soluble in water
As pigment for ceramics, glass,
and enamels
Practically in-
soluble in water.
Grayish-black
crystals
In fungicides, seed protectants,
and wood preservatives; as mordant
in dyeing textiles; in protecting
textiles against ins ects and micro.
organisms. Copper-chromium oxide
as a selective hydrogenation
catalyst
Practically in-
soluble in water.
Yellowish-brown
I crystals
Same as Cupric chromate(III)
(continued)
01
00
-------
APPENDIX
TABLE 7.
PROPERTIES, TOXICITY, AND USES OF SOME CHROMIUM COMPOUNDS (Continued)
Comoound Properties Toxicity Uses
Basic cupric Practically In- Same as Cupr ic chromate(III)
chromate soluble in water.
CuCr04Cu(OH)2 Yellow, copper-
red, or chocolate
brown to 1 i 1 ac
crystals
Basic cupric Practically in- Same as Cupric chromate(III)
chromate soluble in water.
CuCr04.2Cu(OH)2 Light-brown
powder
Basic cupric Practically In- Same as Cupric chromate(III)
chromate soluble in water.
CuCr04 . 3Cu (OH) 2 Yellow to
yellowish-brown
crystals
Copper chromium Stable in at- Same as Cupric chromate(III)
oxide mospheric °2.
A mixture of Practically in-
CuCr204 and CuO soluble in water
lJ1
~
-------
APPENDIX
TABLE 8
CHROMIUM IN HUMAN TISSUE BY AGE IN THE UNITED STATES86
0-45 45 days- 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80+
Tissue days 10 years years years years years years years years years
Kidney 51.8 57.8 3.7 2.3 2.1 3.9 3.0 2.4 2.0* 10.0*
Liver 17.9 16.6 4.6 2.9 1.8 3.1 2.5 1.3 1.1* 1.3*
Lung 85.2 10.2 6.8 8.2 15.6 31.8 24.8 21.0 38.0* 1.1*
Aorta 19.5* 7.0* 7.0 4.2 9.1 4.9 4.2 4.4* 2.6* 0*
Heart 82.4 1.7 2.1 3.3 3.8 6.0 3.7 3.0 2.9* 0*
Pancreas * 2.6* 3.4 2.5 6.5 2.5 3.6 3.7 2.9* 0.9*
Spleen 27.0 4.1* 1.6 1.1 1.7 1.5 1.8 3.0 1.9* 0.3*
Testis '* * 2.1* 1.8 3.1 3.2 2.3 3.6 1.1* 1.0*
*Five or less samples.
0'\
o
-------
APPENDIX
TABLE 9
ANIMAL EXPOSURES TO CHROMATESIO
Species
Type 0 f
Exposure
Rabbits
and
cats
Inhalation
Material
Chromates
Average Dose or
Concentration
Duration
Effect
1,000-50,000 ~g/m3
14 hr/day
1-8 mo
Pathological
changes in
lungs
Rabbits
Inhalation
No effect
Dichromates
11,000-23,000 ~g/m3
as bichromate
2-3 hr for
5 days
-----------------------------------------------------------------------------------------------
Cats Inhalation Dichromate 11,000-23,000 ~g/m3 2-3 hr for Bronchitis,
as bichromate 5 days pneumonia
Mice Inhalation Mixed dust 1,500 ~g/m3 as 4 hr/day No harmful
containing Cr03 5 days/wk effects
chromates for 1 yr
Mice
Inhalation
----~------------------~~------------------------------------------------------~-~---~---------
Mixed dust
containing
chrornates
16,000-27,000 ~g/rn3
as Cro3
1/2 hr / day
in terrni t-
tently
Fatal to
some
strains
Mice
Inhalation
-----------~-----------~---~--------~~----------------------------------~~---~~----------------
Fatal
Mixed dust
containing
chromates
7,000 ~g/rn3 as
Cr03
37 hr over
10 days
Rats
Inhalation
-----------------------~-------~----~--=-=~~--------~------------~~-~--------------------------
Mixed dust
containing
chromates
7,000 ~g/rn3 as
Cro3
37 hr over
10 days
Barely
tolerated
Rabbits
and
guinea
pigs
Inhalation
---------------~---------~=~=-~~~---~-~~-~---~----~--~~~----------~----------------------------
Mixed dust
containing
chromates
5,000 ~g/m3 as
CrO
3
4 hr/day
5 days/wk
1 yr
No marked
effects
0'\
I-'
(continued)
-------
APPENDIX
TABLE 9 (Continued)
ANIMAL EXPOSURES TO CHROMATES
Species
Rats
Type of
ExpOsure
Material
Average Dose or
Concentration
Duration
Effect
Ingestion
Potassium
chromate
added to
drinking
water
500 ppm
Daily
Maximum
nontoxic
level
-----------------------------------------------------------------------------------------------
Mature
rats and
mice
Ingestion
Zinc
chromate
in feed
1%
Daily
Maximum
nontoxic
level
Young
rats
-------------------------------------------------------------~---------------------------------
Daily
Ingestion
Zinc
chromate
in feed
0.12%
Maximum
nontoxic
level
Young
rats
--~--------------------------------------------------------------------------------------------
Daily
Ingestion
Potassium
chromate
in feed
0.12%
Maximum
nontoxic
level
Dogs,
cats,
and
rabbits
Ingestion
Mono- or
dichromates
1,900-5,500 I-1g
chromium/kg body
wt/day (1,000 I-1g
chromium equivalent
to 2,830 I-1g K2Cr207
or 3,800 I-1g K2C:rO 4)
29-685 days
No harmful
effects
Dogs
Fatal in
3 mo
Ingestion
Potassium
dichromate
1,000,000-2,000,000 I-1g
as Cr
Daily
Dogs
-----------------------------------------------------------------------------------------------
1,000,000-10,000,000 I-1g
as Cr
Rapidly
fatal
Stomach tube
Potassium
dichromate
0'\
!\.)
(continued)
-------
APPENDIX
TABLE 9 ( Cant in ued )
ANIMAL EXPOSURES TO CHROMATES
Type of Average Dose or
Species Exposure Material Concentration Duration Effect
Monkeys Subcutaneous Potassium 20,000-700,000 IJ,g Fatal
dichromate 2"~ solution
Dog Subcutaneous Potassium 210,000 IJ,g as Cr Rapidly
dichromate fa tal
-----------------------------------------------------------------------------------------------
Guinea Subcutaneous
pigs
Rabbits Subcutaneous
Rabbits Subcutaneous
Rabbits Subcutaneous
Rabbits Subcutaneous
and or intra-
guinea venous
pigs
Mice Intravenous
Potassium 10,000 IJ,g Lethal
dichromate
Potassium 1.5 cc of 1% solution/ 80% fatal
dichromate kg body wt
Potassium 20,000 IJ,g Lethal
dichromate
Potassium 0.5-1 cc of 0.5% Nephritis
dichromate sOlution/kg body wt
Sodium 100,000=300,000 ~g Rapid death
chromate as Cro3
Zinc
chromate
100 IJ,g/mo as
chromate
zinc
10 mo
Tolerated
Mice
Intravenous
-------------------------------------------------------------------------------~--------------~
Fatal
Zinc
chromate
750 IJ,g
1 dose
Mice
Intravenous
-----------------------------------------------------------------------------------------------
Tolerated
Barium
chromate
2,500 IJ,g/dose as
barium chromate
9 doses at
6-wk. intervals
0"1
w
(continued)
-------
APPENDIX
TABLE 9 (Continued)
ANIMAL EXPOSURES TO CHROMATES
Type of Average Do se or
Species Exposure Material Concentration Duration Effect
Rabbits Intravenous Potassium 0.7 cc of 2"/0 solu- Fatal
dichromate tion/kg body wt
Dogs Intravenous Potassium 10,000,000 ~g Fatal
chromate
-----------------------------------------------------------------------------------------------
Dogs Intravenous Potassium 23,000 ~g Survived
chromate
Dog Intravenous Potassium 210,000 ~g as Cr Rapidly
dichromate fatal
Dog Intravenous Potassium 3,000 ~g/lOO cc 2 doses Marked
dichromate blood/dose kidney
damage
0'\
~
-------
APPENDIX
TABLE 10
68
CONSUMPTION OF CHROMITE IN THE UNITED STATES
(Thousand Short Tons)
Metallurgical Refractory Chemical
Industry Industry Industry Total
Average Average Average Average
Gross Cr203 Gross Cr203 Gross Cr 203 Gross Cr 203
Year Weight % Weight % Wei gh t % Weight %
1957-61 (Avg) 816 46.7 378 34.9 154 45.3 1,348 43.2
1962 590 46.6 365 35.0 176 45.3 1,131 42.7
1963 632 48.7 368 34.6 187 45.1 1,187 43.8
1964 832 49.0 430 33.8 189 45.1 1,451 44.0
1965 907 49.8 460* 34.7* 217* 45.0 1,584 * 44.8*
1966 828 49.6 439 34.6 194 44.9 1,461 44.5
*Revised in 1966.
0'\
U1
-------
66
APPENDIX
TABLE 11
U . S. CON SUMERS OF CHROME OR~ 3
Metallurqical
Chemical
Armco Steel Corp.
Baltimore Works
3400 East Chase St.
Baltimore, Md.
Columbia-Southern Chemical Corp.
902 Garfield Avenue
Jersey City, N. J.
Chromium Mining & Smelting Co.
Riverdale, Ill.
Diamond Alkali Co.
300 Union Commerce Building
Cleveland, Ohio
Interlake Iron Corp.
1900 Union Commerce Building
Cleveland, Ohio
Diamond Alkali Co.
Kearny Plant
Bellevue Turnpike
Kearny, N. J.
Keokuk Electro-Metals Co.
Keokuk, Iowa
Foote Mineral Co., Inc.
10 East Chelton Avenue
Philadelphia, Pac
Montana Ferroalloys, Inc.
P. o. Box 1400
Memphis, Tenn.
Ohio Ferro-Alloys Corp.
839 30th St., N.W.
Canton, Ohio
Frank Samuel & Co., Inc.
Lincoln-Liberty Building
Broad & Chestnut streets
Philadelphia, Pac
Pacific Northeast Alloys, Inc.
P. O. Box 6247, Hillyard Station
Spokane, Wash.
Imperial Paper & Color Corp.
p. O. Box 231
Glen Falls, N. Y.
Pittsburgh Meta~iurgicrl ~o.
Niagara Falls, N. Y.
Solvay Process Division
Allied Chemical & Dye Corp.
P. O. Box 271
Syracuse, N. Y.
Tennessee Products & Ch.::;tjcal. Corp.
2611 West End Avenue
Nashville, Tenn.
Refractory
Union Carbide Metals Co.
30 East 42nd Street
New York, N. Y.
Basic Refractories, Inc.
845 Hanna Building
Cleveland, Ohio
Universal Cyclops Steel Corp.
Bridgeville, Pac
Eastern Stainless Stee.. Corp.
Box 1975 "
Baltimore, Md.
Vanadium Corporation of Arneric:3.
420 Lexington Avenue
New York, N. Y.
"
General Refractories Co.
1520 Locust St.
Philadelphia, Pac
-------
67
APPEND IX
TABLE 11 (Continued)
Refractorv (Continued)
Harbison-Walker Refractories Co.
1800 Farmers Bank Building
Pittsburgh, Pa.
Frank Samuel & Co., Inc.
Lincoln-Liberty Building
Broad & Chestnut Streets
Philadelphia, Pa.
Kaiser Aluminum & Chemical Corp.
1924 Broadway
Oakland, Calif.
E. J. Lavino & Co.
3 Penn Center Plaza
Philadelphia, Pa.
u.S. Steel Corp.
525 William Penn Place
Pittsburgh 3~ Pa.
-------
68
APPENDIX
TABLE 12
PRODUCTION OF CHROMIUM CHEMICALS49
Tvpe of Chemical
Short Tons
1967 19f}f}
28,716 31,409
9,903 10,858
131,348 141,478
Chrome yellow and orange pigments
Molybdate chrome orange
Sodium bichromate and chromate (hydrous)
-------
69
APPENDIX
TABLE 13
28
CHROMIUM CONTENT OF PORTLAND CEMENT
(~g of Cr/g of Cement)
Total
Cr(Vrj Total Cr Total Cr in
in 'Iwo in Two Cr in Untreated
Source Washinqs* Washinqs* Residue Cement
Illinois 1.6 3.5 35.0 42.5
Michigan 1.3 3.3 26.0 28.0
Michigan 4.5 4.8 42.5 50.0
Michigan 7.8 8.8 35.0 45.0
Mississippi 3.7 4.3 43.0 52.0
Missouri 7.2 7.4 57.5 60.0
New York 3.4 5.6 36.0 38.9
Ohio 3.6 3.9 26.9 29.3
Pennsylvania 0.03 1.6 30.9 35.2
Pennsylvania 0.3 4.1 25.0 27.5
Tennessee 1.1 1.9 60.0 60.0
Texas 2.0 2.3 30.0 31.8
Texas 1.5 1.8 32.5 35.0
Mean
Range
2.9
0.03-
7.8
4.1
1.6-
8.8
36.9
25.0-
60.0
41.2
27.5-
60.0
*70-100% of soluble chromium was removed by first washing.
-------
APPENDIX
TABLE 14 2 4-6
CONCENTRATION OF CHROMIUM IN THE AIR '
( I-lg/m3 )
1954-59U 1960 1961 1962 1963 1964 1965
Locationa Max Avo Max Avo Max Avq Max Avo Max Avo Max Avq Max Avq
Alabama
Birmingham .140 .038 .043 .016 .010 .005
Gadsden .000 .000
Huntsville .000 .000
Arizona a
Grand Canyon Pk. .0012 .0011
Maricopa Co. a .0023 .0014
Paradise Valley .000 .000 .002 .002
Phoenix .190 .084 .015 .001 .023 .007
Arkansas a
funtgomery Co. .0025 .0021
Texarkana .005 .001
California
Bakersfield .009 .008
Burbank .018 .009
Humboldt Co. a .0036 .0022
Los Angeles .160 .037 .057 .030 .032 .018 .086 .026 .033 .015
Monterey .008 .005
Pasadena .006 .002 .038 .023
San Bernardino .036 .004
San Francisco .006 .001 .100 .020 .021 .006
San Jose .009 .001 .007 .002
Santa Barbara .016 .006
Colorado
Denver .050 .019 .025 .009 .028 .007 .012 .005
Montezuma Co. a .0037 .0028
Pueblo .000 .000
Connecticut
Bridgeport .006 .003
Hartford .000 .000
New Haven .000 .000
Norwich .000 .000
District Of Columbia
Washington .010 .004 .052 .016 .026 .006 .180 .016
(cont~nued)
.......
a
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHROMIUM IN THE AIR
( ~g/m3)
a 1954-59kJ 1960 1961 1962 1963 1964 1965
Location Max Avq Max Avq Max Avg Max Avq Max Avq Max Avq Max Avg
Florida
St. Petersburg .016 .008
Tampa .160 .032 .018 .004
Georg ia
Atlanta .081 .023 .028 .007 .006 .002
Idaho
Boise .031 .020 .022 .007 .025 .007 .005 .001
Illinois
Chicago .076 .028 .065 .039 .025 .013 .052 .014
Cicero .045 .018
East St. Louis .050 .007 .110 .029
Joliet .000 .000
Moline .009 .007
North Chicago .000 .000
Rock Island .009 .002
Springfield .026 .014
Indiana
Beverly Shore .000 .000
East Chicago .120 .013 .160 .033
Evansville .000 .000
Fort Wayne .000 .000
~ Hammond .031 .008
Indianapolis .081 .024 .100 .042 .068 .016 .020 .008
Muncie a .008 .002
Par~:e Co. .0038 .0027
Terre Haute .007 .003
West Lafayette .006 .002
Iowa
Cedar Rapids .000 .000
Delaware Co. a .0031 .0021
Des Moines .047 .019 .058 .029 .017 .005 .009 .003
Dubuque .000 .000
-..J
......
( continued)
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHRO~UM IN THE AIR
(lJ.g/m )
1954-59JJ 1960 1961 1962 1963 1964 191 -S.
l£>cation a Max Avq Max Avq Max Avq Max Avg Max Avg Max Avg Max Avg
Kansas
Wichita .046 .017 .007 .001
Kentucky
Ashland .010 .007
Covington .018 .012
Louisiana
Lake Charles .000 .000
New Orleans .110 .025 .045 .010 .017 .011
Maine -
Acadia Natl. Pk. a .020 .0091
Maryland
Baltimore .290 .094 .430 .108 .350 .069 .028 .018
Calvert Co. a. .0016 .0010
Cumberland .000 .000
Massachusetts
Boston .350 .051 .013 .007
Brockton .000 .000
Lynn .000
Somerville .000 .000
Springfield .000 .000
Michigan
Detroit .082 .029 .038 .016 .033 .010 .049 .014
Grand Rapids .012 .010
Kalamazoo .029 .019
Muskegon .007 .003
Minnesota
Minneapolis .070 .020 .022 .002
M:>orhead .000 .000
St. Paul .020 .013
Mississippi 51.
Jackson Co. .027 .012
Missouri
Shannon Co. a .0019 .0014
St. Louis .130 .041 .065 .021 .063 .020 .026 .007
(contlnued)
-...J
N
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHROMIUM IN THE AIR
( ~g/m3 )
a 1954-59JJ 1960 1961 1962 1963 1964 1965
Location Max Avq Max Avq Max Avg Max Avg Max Avq Max Avg Max Avg
~ntana
Glacier a .0038 .0016
Natl.Pk.
Helena .007 .001
Nebraska
Lincoln .000 .000
Thomas Co. a .0026 .0019
Nevada
Las Vegas .061 .031 .024 .014 .031 .008 .009 .001
Reno .000 .000
White Pine Co. a .0028 .0012
New Hampshire
Coos Co. a .0022 .0011
New Jersey
Bayonne .025 .015 .011
Bridgeton .005 .003
Camden .008 .018 .014 .011 .010
Newark .130 .046 .069 .020 .063 .020
Paterson .011 .010
New Mexico
Albuquerque a .130 .057 .006 .006 .002
Rio Arriba Co. .0053 .0045
New York I
I
Buffalo .059 .010
Cape Vincent i!I. .021 .0069
Glen Cove .027 .019
Massena .027 .019
Mt. Vernon .039 .035
New Rochelle .032 .022
New York .073 .021 .078 .027 .042 .016 .019 .006
Rochester .290 .055 .042 .036
Troy .024 .015
I
(continued)
-...J
LV
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHRO~IUM IN THE AIR
(~g/m )
195~ -59.>.) le 60 1961 1962 1963 1964 1965
Location a Max Avq Max Avg Max Avq Max Avq Max Avg Max Avg Max Avg
North Carolina
Asheville .026 .020
Cape Hatterasa. .0027 .0015
Charlotte .071 .023 .016 .002
Durham .008 .007
Winston-Salem .030 .016
Ohio
Akron .130 .041 .011 .009
Cincinnati .039 .009 .200 .086 .140 .053 .260 .063 .100 .023 .240 .040
Cleveland .130 .043 .035 .017 .034 .020 .047 .014
Youngstown .075 .047 .170 .051 .030 .005 .054 .012
Oklahoma
Cherokee Co. a .0017 .0010
Tulsa .028 .016
Oregon
Curry Co. a .0014 .00035
Portland .071 .025 .041 .004 .023 .004
Pennsylvania
Allentown .054 .036 .000
Altoona .006 .001 " .009 .002 .007 .002
Bethlehem .130 .048 .010 .005
Clarion Co. a .0091 .0070
Johnstown .060 .010
Lancaster .028 .016
Philadelphia .078 .026 .120 .049 .057 .024 .100 .018 .042 .013 . 028 .011
Pittsburgh .200 .028 . 380 .197 .120 .041 .090 .023 . 097 .021
Scranton .052 .030
Puerto Rico
Bayamon .000 .000
Rhode Island
East Providence .000 .000
Washington Co. a .0055 .0036
(continued)
......
~
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHROMIUM IN THE AIR
(~g/m3)
a 1954-59LJ 1960 1961 1962 1963 19.64 19 i5
Location Max Avq Max Avq Max Avq Max Avq Max Avq Max Avg Max Avg
South Carolina
Richland Co. a .0040 .0020
South Dakota
Black Hills Frsta .0011 .00055
Tennessee
Chattanooga .002 .130 .041 .053 .015
Memphis .006
Nashville .076 .029 .069 .011
Texas
El Paso .015 .006 .000
Houston : .140 .025 .015 .004
a .0032 .0026
Matagorda Co.
Odessa .000 .000
Tyler .007 .002
Utah
Salt Lake City .009 .019 .007 .001
Vermont
Orange Co. a .0044 .0026
Virginia '
Portsmouth .006 .004
Richmond .000 .000
Shenandoah Pk.a .0029 .0018
Washington
Seattle .200 .047 .330 .039 .100 .015
Spokane .092 .041
Tacoma .120 .018 .024 .002 .022 .001 '
west Virginia
Charleston .290 .097 .360 .132 .180 .044
Huntington .042 .021
Wisconsin
Door Co. a .0024 .0018
Milwaukee .088 .029 .039 .010
--.J
U1
( continued)
-------
APPENDIX
TABLE 14 (Continued)
CONCENTRATION OF CHRO~IUM IN THE AIR
(lJ.g/m )
1954-59J.J I 1960 1961 1962 1963 1964 1965
Locationa Max Ava Max Avq Max Avq Max Avq Max Avq Max Avq Max A~
Wyoming
Cheyenne .030 .011 .000
Yellowstone Nat.l. .0027 .00068
Pk.
a
All locations are urban unless indicated with an * which indicates nonurban.
b
The data in this column may include only one year or the average of all
measurements made during these years.
---.J
'"
------- |