INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
ENVIRONMENTAL HEALTH CRITERIA 106
BERYLLIUM
This report contains the collective views of an international group of
experts and does not necessarily represent the decisions or the stated
policy of the United Nations Environment Programme, the International
Labour Organisation, or the World Health Organization.
Published under the joint sponsorship of
the United Nations Environment Programme,
the International Labour Organisation,
and the World Health Organization
World Health Orgnization
Geneva, 1990
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development of know-how for coping with chemical accidents,
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chemicals.
WHO Library Cataloguing in Publication Data
Beryllium.
(Environmental health criteria ; 106)
1.Beryllium
I.Series
ISBN 92 4 157106 3 (NLM Classification: QV 275)
ISSN 0250-863X
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CONTENTS
ENVIRONMENTAL HEALTH CRITERIA FOR BERYLLIUM
1. SUMMARY AND CONCLUSIONS
1.1. Identity, physical and chemical properties, analytical
methods
1.2. Sources of human and environmental exposure
1.3. Environmental transport, distribution, and
transformation
1.4. Environmental levels and human exposure
1.5. Kinetics and metabolism
1.6. Effects on organisms in the environment
1.7. Effects on experimental animals and in vitro test
systems
1.8. Effects on human beings
1.9. Evaluation of human health risks and effects on the
environment
1.9.1. Human health risks
1.9.2. Effects on the environment
2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.1.1. Pure beryllium and beryllium compounds
2.1.2. Impure beryllium compounds
2.2. Physical and chemical properties
2.3. Analytical methods
2.3.1. Sampling procedure and sample preparation
2.3.1.1 Sampling
2.3.1.2 Sample decomposition
2.3.1.3 Separation and concentration
2.3.2. Detection and measurement
3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Man-made sources
3.2.1. Industrial production and processing
3.2.1.1 Production levels
3.2.1.2 Manufacturing process
3.2.1.3 Emissions during production and use
3.2.1.4 Disposal of wastes
3.2.2. Coal and oil combustion
3.3. Uses
4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Ambient air
5.1.2. Surface waters and sediments
5.1.3. Soil
5.1.4. Food and drinking-water
5.1.5. Tobacco
5.1.6. Environmental organisms
5.1.6.1 Plants
5.1.6.2 Animals
5.2. General population exposure
5.3. Occupational exposure
5.3.1. Exposure levels
5.3.2. Occupational exposure standards
5.3.3. Biological monitoring
6. KINETICS AND METABOLISM
6.1. Absorption
6.1.1. Respiratory absorption
6.1.2. Dermal absorption
6.1.3. Gastrointestinal absorption
6.2. Distribution and retention
6.3. Elimination and excretion
6.4. Biological half-life
7. EFFECTS ON ORGANISMS IN THE ENVIRONMENT
7.1. Microorganisms
7.2. Aquatic organisms
7.2.1. Plants
7.2.2. Animals
7.3. Terrestrial organisms
7.3.1. Plants
7.3.2. Animals
8. EFFECTS ON EXPERIMENTAL ANIMALS AND IN VITRO TEST SYSTEMS
8.1. Single exposures
8.2. Short- and long-term exposures
8.2.1. Short-term exposure
8.2.1.1 Oral
8.2.1.2 Inhalation
8.2.1.3 Other
8.2.2. Long-term exposure
8.2.2.1 Oral
8.2.2.2 Inhalation
8.3. Skin irritation and sensitization
8.4. Reproduction, embryotoxicity, and teratogenicity
8.5. Mutagenicity and related end-points
8.5.1. DNA damage
8.5.2. Mutation
8.5.2.1 Bacteria and yeast
8.5.2.2 Cultured mammalian cells
8.5.3. Chromosomal effects
8.6. Carcinogenicity
8.6.1. Bone cancer
8.6.2. Lung cancer
8.7. Mechanisms of toxicity, mode of action
8.7.1. Effects on enzymes and proteins
8.7.2. Immunological reactions
9. EFFECTS ON HUMAN BEINGS
9.1. General population exposure
9.2. Occupational exposure
9.2.1. Effects of short- and long-term exposure
9.2.1.1 Acute disease
9.2.1.2 Chronic disease
9.3. Carcinogenicity
9.3.1. Epidemiological studies
10. EVALUATION OF HUMAN HEALTH RISKS AND EFFECTS ON THE
ENVIRONMENT
10.1. Evaluation of human health risks
10.2. Evaluation of effects on the environment
10.3. Conclusions
10.3.1. Acute beryllium disease
10.3.2. Chronic beryllium disease
10.3.3. Cancer
11. RECOMMENDATIONS
12. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES
REFERENCES
RESUME
RESUMEN
WHO TASK GROUP ON ENVIRONMENTAL HEALTH CRITERIA FOR BERYLLIUM
Members
Dr V. Bencko, Institute of Tropical Health, Postgraduate School of
Medicine and Pharmacy, Prague, Czechoslovakia
Dr A.W. Choudhry, Division of Environmental and Occupational
Health, Kenya Medical Research Centre (KEMRI), Nairobi, Kenya
(Chairman)
Dr R. Hertel, Fraunhofer Institute of Toxicology and Aerosol
Research, Hanover, Federal Republic of Germany
Dr P.F. Infante, Office of Standards Review, Occupational Safety
and Health Administration, US Department of Labor, Washington,
DC, USA
Professor A. Massoud, Department of Community, Environmental and
Occupational Medicine, Ain Shams University, Abbassia, Cairo,
Egypt
Dr L.A. Naumova, Institute of Industrial Hygiene and Occupational
Diseases, Moscow, USSR (Vice-Chairman)
Professor A.L. Reeves, Faculty of Allied Health Professions,
Department of Occupational and Environmental Health, Wayne State
University, Detroit, Michigan, USA
Dr G. Rosner, Fraunhofer Institute of Toxicology and Aerosol
Research, Hanover, Federal Republic of Germany (Rapporteur)
Representatives of Nongovernmental Organizations
Dr A.V. Roscin, representative of the International Commission on
Occupational Health (ICOH), also a designated national observer,
Central Institute for Advanced Medical Training, Moscow, USSR
Observers
Dr N.A. Khelkovsky-Sergeev, Institute of Industrial Hygiene and
Occupational Diseases, Moscow, USSR
Secretariat
Dr Z. Grigorevskaya, Centre for International Projects, Moscow,
USSR (Project Officer)
Dr E.M. Smith, International Programme on Chemical Safety, Division
of Environmental Health, World Health Organization, Geneva,
Switzerland (Secretary)
Dr V. Turosov (also representing International Agency for Research
on Cancer), Cancer Research Center, Academy of Medical Sciences
of the USSR, Moscow, USSR
NOTE TO READERS OF THE CRITERIA DOCUMENTS
Every effort has been made to present information in the
criteria documents as accurately as possible without unduly
delaying their publication. In the interest of all users of the
environmental health criteria documents, readers are kindly
requested to communicate any errors that may have occurred to the
Manager of the International Programme on Chemical Safety, World
Health Organization, Geneva, Switzerland, in order that they may be
included in corrigenda, which will appear in subsequent volumes.
* * *
A detailed data profile and a legal file can be obtained from
the International Register of Potentially Toxic Chemicals, Palais
des Nations, 1211 Geneva 10, Switzerland (Telephone no.
7988400/7985850).
ENVIRONMENTAL HEALTH CRITERIA FOR BERYLLIUM
A WHO Task Group on Environmental Health Criteria for Beryllium
met at the Ukrania Hotel, Moscow, USSR, from 3 to 7 July 1989,
under the auspices of the USSR State Committee for Environmental
Protection, Centre for International Projects. Dr S.N. Morozov
welcomed the participants on behalf of the host institution and
Dr E. Smith opened the meeting on behalf of the three cooperating
organizations of the IPCS (ILO/UNEP/WHO). The Task Group reviewed
and revised the draft criteria document and made an evaluation of
the health risks of exposure to beryllium.
The first draft of this document was prepared by Dr R. HERTEL
and Dr G. ROSNER, Fraunhofer Institute for Toxicology and Aerosol
Research, Hanover, Federal Republic of Germany. This draft was
reviewed in the light of international comments by a Working Group
comprising Dr V. BENCKO, Prague, Czechoslovakia, Dr M. PISCATOR,
Stockholm, Sweden, Dr F.W. SUNDERMAN, Farmington, Connecticut, USA,
with the assistance of Dr R. Hertel and Dr G. Rosner. The revised
draft resulting from this Working Group was submitted for the Task
Group review. Dr E. SMITH, IPCS Central Unit, was responsible for
the overall scientific content of the document and the organization
of the meetings, and Mrs M.O. HEAD of Oxford, England, was
responsible for the editing.
The efforts of all who helped in the preparation and
finalization of the document are gratefully acknowledged.
* * *
Financial support for the Task Group was provided by the United
Nations Environment Programme, through the USSR Commission for
UNEP. Partial financial support for the publication of this
criteria document was kindly provided by the United States
Department of Health and Human Services, through a contract from
the National Institute of Environmental Health Sciences, Research
Triangle Park, North Carolina, USA-a WHO Collaborating Centre for
Environmental Health Effects.
1. SUMMARY AND CONCLUSIONS
1.1 Identity, Physical and Chemical Properties, Analytical Methods
Beryllium is a steel-grey, brittle metal, existing naturally
only as the 9Be isotope. Its compounds are divalent. Beryllium
has several unique properties. It is the lightest of all solid
and chemically-stable substances, with an unusually high melting
point, specific heat, heat of fusion, and strength-to-weight ratio.
It has excellent electrical and thermal conductivities. Because of
its low atomic number, beryllium is very permeable to X-rays. Its
nuclear properties include the breaking, scattering, and reflecting
of neutrons, as well as the emission of neutrons on alpha-
bombardment.
Beryllium has a number of chemical properties in common with
aluminium, particularly its high affinity for oxygen. Hence, a
very stable surface film of beryllium oxide (BeO) is formed on the
surface of metallic beryllium and beryllium alloys, providing high
resistance to corrosion, water, and cold oxidizing acids. When
ignited in oxygen, beryllium powder burns with a temperature of
4500 °C. Sintered beryllium oxide ("beryllia") is very stable and
possesses ceramic properties. Cationic beryllium salts are
hydrolysed in water and react to form insoluble hydroxides or
hydrated complexes at pH values in the range of 5 - 8, and
beryllates, above pH 8.
As an additive in alloys, beryllium confers a combination of
outstanding properties on other metals, particularly, resistance to
corrosion, high modulus of elasticity, non-magnetic and non-
sparking characteristics, increased electrical and thermal
conductivities, and a greater strength than that of steel.
A variety of analytical methods have been used to determine
beryllium in various media. Older methods include spectroscopic,
fluorometric, and spectrophotometric techniques. Flameless atomic
absorption spectrometry and gas chromatography are the methods of
choice; the detection limits are 0.5 ng/sample (flameless atomic
absorption) and 0.04 pg/sample (gas chromatography with electron-
capture detection). In addition, inductively coupled plasma atomic
emission spectrometry is being increasingly used.
1.2 Sources of Human and Environmental Exposure
Beryllium is the 35th most abundant element in the earth's
crust, with an average content of about 6 mg/kg. Apart from the
gemstones, emerald (chromium-containing beryl) and aquamarine
(iron-containing beryl), only 2 beryllium minerals are of economic
significance. Beryl contains up to 4% of beryllium and is mined in
Argentina, Brazil, China, India, Portugal, the USSR, and in several
countries in southern and central Africa. Although it contains
less than 1% beryllium, bertrandite has become the main source of
this metal in the USA.
The annual global production of beryllium minerals in the
period 1980 - 84 was estimated to be around 10 000 tonnes, which
corresponds to approximately 400 tonnes of beryllium. Despite the
considerable fluctuations in beryllium supply and demand resulting
from sporadic government programmes in armaments, nuclear energy,
and aerospace, demand for beryllium was expected, in 1986, to
increase at an average annual rate of about 4% up to 1990.
In general, beryllium emissions during production and use are
of minor importance compared with emissions that occur during the
combustion of coal and fuel oil, which have natural average
contents of 1.8 - 2.2 mg Be/kg dry weight, and up to 100 µg
Be/litre, respectively. Beryllium emission from the combustion of
fossil fuels amounted to approximately 93% of the total beryllium
emission in the USA, one of the main producer countries. Improved
control measures can substantially reduce the emission of beryllium
from power plants.
Though the combustion of fossil fuels determines the beryllium
background levels in ambient air, production-related sources can
lead to locally elevated ambient concentrations, particularly where
there are insufficient control measures. Similarly, emissions
arising from the testing and use of beryllium-powered rockets could
be of potential local significance. In occupational settings,
exposure occurs mainly during the processing of beryllium ores,
metallic beryllium, beryllium-containing alloys, and beryllium
oxide. Production industries exist only in Japan, the USA, and the
USSR. In other countries, the imported pure metal, alloys, or
ceramic beryllium oxide are processed to end products.
Most beryllium waste results from pollution control measures
and is either recycled or buried. Recycling of the majority of
end-products is not economically worth while because of their small
volume and low beryllium content.
Approximately 72% of the world production of beryllium is used
in the form of beryllium-copper and other alloys in the aerospace,
electronics, and mechanical industries. About 20% is used as the
free metal, mainly in the aerospace, weapons, and nuclear
industries. The remainder is used as beryllium oxide for ceramic
applications, principally in electronics and microelectronics.
1.3 Environmental Transport, Distribution, and Transformation
Data concerning the fate of beryllium in the environment are
limited. Atmospheric beryllium oxide particles return to earth
through wet and dry deposition. Within the environmental pH range
of 4 - 8, beryllium is strongly absorbed by finely-dispersed
sedimentary minerals, thus preventing release to ground water.
Beryllium is believed not to biomagnify to any extent within
food chains. Most plants take up beryllium from the soil in small
amounts, and very little is translocated from the roots to other
plant parts.
1.4 Environmental Levels and Human Exposure
Beryllium concentrations in surface and drinking-waters are
usually in the low µg/litre range. Levels in soils range between 1
and 7 mg/kg. Terrestrial plants generally contain less than 1 mg
beryllium/kg dry weight. Amounts of up to approximately 100 µg/kg
fresh weight have been found in various marine organisms.
Atmospheric beryllium concentrations at rural sites in the USA
ranged from 0.03 to 0.06 ng/m3. In countries with less fossil fuel
combustion, background levels should be lower. Annual average
beryllium concentrations in urban air in the USA were found to
range from <0.1 to 6.7 ng/m3. In Japanese cities, an average of
0.04 ng/m3 was found with the highest values (0.2 ng/m3) occurring
in industrial areas.
Before the establishment of control measures in the 1950s,
atmospheric beryllium concentrations were extremely high in the
vicinity of production and processing plants. In addition,
"para-occupational" exposure used to occur in workers' families,
known as neighbourhood cases, which were related to contact with
the worker's clothes, atmospheric exposure, or both. Today, these
sources of exposure are normally insignificant for the general
population. The principal source of environmental exposure of the
general population to airborne beryllium is the combustion of
fossil fuels. Exceptionally high exposure could occur in the
vicinity of power plants that burn coal containing high levels of
beryllium and do not apply adequate control measures. Tobacco
smoking is probably another important source of beryllium exposure.
The growing use of beryllium in base dental casting alloys
could be of some significance for the general population, because
of the high potential of beryllium to provoke contact allergic
reactions.
Prior to 1950, exposure to beryllium in working environments
was usually very high, and concentrations exceeding 1 mg/m3 were
not unusual. Control measures to meet the occupational standards
of 1 - 5 µg Be/m3 (time-weighted average), established by various
countries, have drastically reduced work-place concentrations of
beryllium, though these values are not being achieved everywhere.
Levels of beryllium in tissues or body fluids may be indicative
of a previous exposure situation. In persons who have not been
specifically exposed, levels in the urine are around 1 µg/litre and
those in lung tissue, less than 20 µg/kg (dry weight). The limited
data available do not allow the substantiation of a clear
relationship between exposure and body burden, though clearly
elevated levels (>20 µg/kg) have been found in lung tissue samples
from patients with beryllium disease.
1.5 Kinetics and Metabolism
There are no human data on the deposition or absorption of
inhaled beryllium. Animal studies have shown that, after being
deposited in the lungs, beryllium remains there and is slowly
absorbed into the blood. Pulmonary clearance is biphasic, with a
fast elimination phase in the first 1 - 2 weeks following cessation
of exposure.
Most of the beryllium circulating in the blood is transported
in the form of a colloidal phosphate. A significant part of the
inhaled dose is incorporated into the skeleton, which is the
ultimate site of beryllium storage. Generally, inhalation exposure
also results in long-term storage of appreciable amounts of
beryllium in lung tissue, particularly in pulmonary lymph nodes.
More soluble beryllium compounds are also translocated to the
liver, abdominal lymph nodes, spleen, heart, muscle, skin, and
kidney.
Following oral administration of beryllium, a small amount
(less than 1% of the dose) is generally absorbed into the blood and
stored in the skeleton. Small amounts have also been found in the
gastrointestinal tract and in the liver.
The absorption of beryllium through intact skin is negligible,
as beryllium is bound by epidermal constituents.
A considerable proportion of absorbed beryllium is rapidly
eliminated, mainly in the urine, and, to a small extent, in the
faeces. Part of inhaled beryllium is also eliminated in the
faeces, probably as a result of clearance from the respiratory
tract and ingestion of swallowed beryllium.
Because of the long storage of beryllium in the skeleton and
lungs, its biological half-life is extremely long. A half-life of
450 days has been calculated for the human skeleton.
1.6 Effects on Organisms in the Environment
Soil microorganisms grown in a magnesium-deficient medium grow
better in the presence of beryllium, because of the partial
substitution of beryllium for magnesium in the organisms'
metabolism. Similar growth-stimulating effects have been noted in
algae and crop plants. This phenomenon seems to be pH-dependent,
as it only occurs at high pH. At pH 7 or below, beryllium is toxic
for aquatic and terrestrial plants, regardless of the magnesium
levels in the growth medium.
Generally, plant growth is inhibited by soluble beryllium
compounds at mg/litre concentrations. For example, in bush beans
(Phaseolus vulgaris) grown in nutrient solution at pH 5.3, an 88%
yield reduction was observed at a concentration of 5 mg Be/litre.
Effects were first observed on the roots, which turned brown and
failed to resume normal elongation. Roots accumulate most of the
beryllium taken up, and very little is translocated to the upper
parts of the plant. The critical contents of beryllium resulting
in a 50% decrease in yield were estimated to be about 3000 mg Be/kg
dry weight and 6 mg Be/kg, respectively, in the roots and outer
leaves of cabbage plants (Brassica oleracea).
Stunting of both roots and foliage was noted in soil cultures
of beans, wheat, and ladino clover, but no chlorosis or mottling of
the foliage occurred.
In soil culture, beryllium phytotoxicity is governed by the
nature of soil, particularly its cation exchange capacity and the
pH of the soil solution. Apart from the magnesium-substituting
effect, the diminished phytotoxicity under alkaline conditions also
results from the precipitation of beryllium as unavailable
phosphate salt.
The mechanism underlying the phytotoxicity of beryllium is
probably based on the inhibition of specific enzymes, particularly
plant phosphatases. Beryllium also inhibits uptake of essential
mineral ions.
In acute toxicity studies on different freshwater fish species,
LC50 values were found to vary from 0.15 to 32 mg Be/litre,
depending on species and test conditions. Toxicity to fish
increased with decreasing water hardness; beryllium sulfate was one
to two orders of magnitude more toxic for fathead minnows and
bluegills in soft water than in hard water. Salamander larvae and
the waterflea (Daphnia magna) showed a similar sensitivity.
There are no validated data on the long-term toxicity of
beryllium in aquatic animals. However, one unpublished study has
provided evidence of Daphnia magna being adversely affected at
considerably lower concentrations (5 µg Be/litre) in long-term
reproduction tests than in acute toxicity tests (EC50, 2500 µg
Be/litre).
1.7 Effects on Experimental Animals and In Vitro Test Systems
Symptoms of acute beryllium poisoning in experimental animals
were respiratory disorders, spasms, hypoglycaemic shock, and
respiratory paralysis.
Implantation of beryllium compounds and metallic beryllium in
the subcutaneous tissues may produce granulomas, similar to those
observed in human beings. Guinea-pigs developed cutaneous
hypersensitivity on intradermal injection of soluble beryllium
compounds.
As a secondary effect, beryllium carbonate produced rickets
(rachitis) in young rats, through intestinal precipitation of
beryllium phosphate and concomitant phosphorus deprivation.
Acute chemical pneumonitis occurred in various animal species
following the inhalation of beryllium metal or different beryllium
compounds, including insoluble forms. Repeated daily exposure to
beryllium sulfate mist, at a mean concentration of 2 mg Be/m3, was
lethal for rats (90% deaths), dogs (80%), cats (80%), rabbits
(10%), guinea-pigs (60%), monkeys (100%), goats (100%), hamsters
(50%), and mice (10%). Because of a synergistic effect of the
fluoride ion, the effects of beryllium fluoride were about twice as
great as those of the sulfate. Some of the lesions in the lungs
resembled those in man, but the granulomas were not identical.
The inhalation toxicity of insoluble beryllium oxide depends to
a great extent on its physical and chemical properties, which can
alter considerably, depending on production conditions. Because
its ultimate particle size is smaller and there is less
aggregation, low-fired BeO (400 °C) at 3.6 mg Be/m3 for 40 days
caused mortality in rats and marked lung damage in dogs, whereas
high-fired BeO grades (1350 °C and 1150 °C) did not produce
pulmonary damage, in spite of a higher total exposure (32 mg Be/m3,
360 h).
The characteristic non-malignant response to long-term, low-
level inhalation exposure to soluble and insoluble beryllium
compounds is chronic pneumonitis associated with granulomas, which
only partly corresponds to the chronic disease seen in humans
beings.
The results of genotoxicity tests indicate that beryllium
interacts with DNA and causes gene mutations, chromosomal
aberrations, and sister chromatid exchange in cultured mammalian
somatic cells, though it was not mutagenic in bacterial test
systems.
Intravenous (3.7 - 700 mg Be) and intramedullary (0.144 - 216
mg Be) injection of beryllium metal and various compounds produced
osteosarcomas and chondrosarcomas in rabbits, with metastases
occurring in 40 - 100% of the animals, most frequently in the
lungs.
In rats, inhalation (0.8 - 9000 µg Be/m3) or intratracheal
(0.3 - 9 mg Be) exposure to soluble and insoluble beryllium
compounds, beryllium metal, and various beryllium alloys induced
lung tumours of the adenoma or adenocarcinoma type, partly
metastasizing. Beryl (620 µg Be/m3) was the only beryllium ore
that caused lung carcinomas (bertrandite, at 210 µg Be/m3, did
not). Beryllium oxide proved carcinogenic to rats, but the
incidence of pulmonary adenocarcinomas was much higher after
intratracheal administration (9 mg Be) of a low-fired specification
(51%) compared with high-fired oxides (11 - 16%). At the time of
many of these studies, study design and laboratory practice did not
usually comply with current practices. Thus, the reported
inhalation exposure data should be considered with particular care.
The induction of pulmonary cancer by beryllium is highly
species-specific. While rats and, perhaps, monkeys are very
susceptible in this respect, no pulmonary tumours have been
observed in rabbits, hamsters, or guinea-pigs.
Mechanisms for beryllium toxicity have been based on 3
theories: (1) beryllium affects phosphate metabolism by inhibiting
crucial enzymes, particularly alkaline phosphatase; (2) beryllium
inhibits replication and cell proliferation by affecting enzymes of
nucleic acid metabolism; and (3) beryllium toxicity involves an
immunological mechanism, as shown in guinea-pigs, which develop
cell-mediated hypersensivity in the skin.
1.8 Effects on Human Beings
Toxicologically relevant exposure to beryllium is almost
exclusively confined to the work-place. Before the introduction of
improved emission control and hygiene measures in beryllium plants,
several "neighbourhood" cases of chronic beryllium disease were
reported. By 1966, a total of 60 cases had been reported in the
USA, some of which were related to contact with workers' clothes
("para-occupational" exposure) or to air exposure in the close
vicinity of beryllium plants. No cases have been reported in
recent years.
Recently, several cases of an allergic contact stomatitis,
probably caused by beryllium-containing dental prostheses, have
been reported.
In the 1930s and 1940s, several hundred cases of acute
beryllium disease occurred, particularly in workers in beryllium-
extraction plants in Germany, Italy, the USA, and the USSR.
Inhalation of soluble beryllium salts, particularly the fluoride
and sulfate, at concentrations exceeding 100 µg Be/m3, consistently
produced acute symptoms among almost all exposed workers, while, at
a level of 15 µg/m3 and below (determined using out-of-date
analytical methods), no cases were registered. After adoption of a
maximum exposure concentration of 25 µg/m3 in the early 1950s,
cases of acute beryllium disease drastically decreased.
Signs and symptoms of acute beryllium disease range from mild
inflammation of the nasal mucous membranes and pharynx to
tracheobronchitis and severe chemical pneumonitis. In severe
cases, patients died of acute pneumonitis, but in most cases, after
cessation of exposure, complete recovery occurred within 1 - 4
weeks. In a few cases, chronic beryllium disease developed years
after recovery from the acute form.
Direct contact with soluble beryllium compounds causes contact
dermatitis and possibly conjunctivitis. Sensitized individuals
react much more rapidly and to lower amounts of beryllium. Soluble
or insoluble beryllium compounds, introduced in, or beneath, the
skin produce chronic ulcerations, with granulomas often appearing
after several years.
Chronic beryllium disease differs from the acute form in having
a latent period ranging from several weeks up to more than 20
years; it is of long duration and progressive in severity. In the
US Beryllium Case Registry (a central file on reported cases of
beryllium disease, established in 1952) 888 cases were registered
up to 1983. Six hundred and twenty two cases were classified as
chronic, of which 557 resulted from occupational exposure, mainly
within the fluorescent lamp industry (319 cases) or within
beryllium extraction plants (101 cases). After the use of zinc
beryllium silicate and beryllium oxide in fluorescent tube
phosphors was abandoned in 1949, and an occupational exposure limit
(TWA, 2 µg Be/m3) was adopted, cases of chronic beryllium disease
dramatically decreased, but new cases resulting from exposure to an
air concentration of around 2 µg/m3 have been recorded.
The term "chronic beryllium disease" is preferred to the term
"berylliosis", because this disease differs from a typical
pneumoconiosis. Granulomatous inflammation of the lung, associated
with dyspnoea on exertion, cough, chest pain, weight loss, fatigue,
and general weakness, is the most typical feature; right heart
enlargement with accompanying cardiac failure, hepatomegaly,
splenomegaly, cyanosis, and finger clubbing may also occur.
Changes in serum proteins and liver function, renal stones, and
osteosclerosis have also been found to be associated with chronic
beryllium disease. The evolution of chronic beryllium disease is
not uniform; in some cases, spontaneous remission for weeks or
years is encountered, followed by exacerbations. In the majority
of cases, progressive pulmonary disease is seen with an increased
risk of death from cardiac or respiratory failure. The reported
morbidity rates among beryllium workers vary from 0.3 to 7.5%. In
patients with chronic beryllium disease, the mortality rates are as
high as 37%.
Macroscopically, the lungs may show diffuse changes, with
widespread scattered small nodules and interstitial fibrosis.
Microscopically, there are sarcoid-like granulomas with varying
amounts of interstitial inflammation, which are usually
indistinguishable from those in other granulomatoses, such as
sarcoidosis or tuberculosis.
History taking and tissue analysis serve as a valuable basis in
the diagnosis of beryllium disease, though the presence of
beryllium in biological material does not prove the presence of
disease. Patch testing is not recommended, because it is not very
reliable and is itself highly sensitizing. The most useful
diagnostic aids are the macrophage migration inhibition assay and
the lymphocyte-blast transformation test.
These methods of measuring hypersensitivity are based on an
immune mechanism that probably underlies chronic beryllium disease
and the delayed cutaneous and granulomatous hypersensitivity.
The great variability in latency and the lack of dose-response
relationships in chronic beryllium disease may be explained by
immunological sensitization. Pregnancy seems to be a precipitating
"stress factor", as 66% of 95 females, registered among the fatal
cases in the US Beryllium Case Registry, were pregnant.
Sources of exposure for patients with beryllium disease also
include beryllium metal alloy production, machining, ceramics
production and research, and energy production. The present
occupational exposure standards may not exclude the development of
chronic beryllium disease in sensitized individuals.
In several epidemiological studies, the carcinogenicity of
beryllium has been examined among workers employed in two US
beryllium production facilities and among clinical cases in a
registry of beryllium-related lung conditions, derived from these
facilities and other occupations. The results of these studies
have been questioned on the grounds of selection bias, confounding
from cigarette smoking, and underestimation of the expected number
of lung cancer deaths, since mortality rates for the period
1965 - 67 had been used to estimate expected mortality for the
years 1968 - 75. While the first two issues are unlikely to have
played a major role in the excess lung cancer risk, the data
presented in this document have been based on an "adjusted"
expected number of lung cancer deaths. Significantly elevated
risks of lung cancer were noted in all studies.
1.9 Evaluation of Human Health Risks and Effects on
the Environment
1.9.1 Human health risks
Provided that the control measures in the beryllium industry
are adequate, general population exposure today is mainly confined
to low levels of airborne beryllium from the combustion of fossil
fuels. In exceptional cases, where coal with an unusually high
beryllium content is burned, health problems could arise. The use
of beryllium for dental prostheses should be reconsidered, because
of the high sensitization potential of beryllium.
Cases of acute beryllium disease resulting in nasopharyngitis,
bronchitis, and severe chemical pneumonitis have drastically
decreased and, today, may only occur as a consequence of failures
in control measure systems. Chronic beryllium disease differs from
the acute form in having a latent period of several weeks to more
than 20 years; it is of long duration and progressive in severity.
The lung is mainly affected; granulomatous inflammation, associated
with dyspnoea on exertion, cough, chest pain, weight loss, and
general weakness, is the typical feature. Effects on other organs
may be of a secondary nature, rather than systemic. The great
variability in latency and the lack of dose-response may still
occur today among sensitized individuals who have experienced
exposure to a concentration of around 2 µg/m3.
Despite some deficiencies in study design and laboratory
practice, the carcinogenic activity of beryllium in different
animal species has been confirmed.
Several epidemiological studies have provided evidence of an
excess lung cancer risk from occupational exposure to beryllium.
Although a number of criticisms have been raised about the
interpretation of these results, available data lead to the
conclusion that beryllium is the most likely single explanation for
the excess lung cancer observed in the exposed workers.
1.9.2 Effects on the environment
Data concerning the fate of beryllium in the environment,
including its effects on aquatic and terrestrial organisms, are
limited. Beryllium levels in surface waters (µg/litre range) and
soils (mg/kg dry weight range) are usually low and probably do not
negatively affect the environment.
2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
The element beryllium (Be) was discovered in 1798 by the French
chemist Vauquelin, who prepared the hydroxide of beryllium. The
metallic element was first isolated in independent experiments by
Wöhler (1828) and Bussy (Anon, 1828). Owing to the sweet taste of
its salts, the new element was called glucinium (G) by Bussy.
Today this name is still used in the French chemical literature.
In 1957, Wöhler's name "beryllium" was officially recognized by
IUPAC (Ballance et al., 1978).
2.1 Identity
2.1.1 Pure beryllium and beryllium compounds
Pure beryllium is a steel-grey, brittle metal, the first
element of the second group (alkaline earths) and the third element
of the first period of the periodic table. Its compounds are
divalent.
Synonyms, trade names, and the chemical formulae of pure
beryllium and some of its compounds are given in Table 1.
2.1.2 Impure beryllium compounds
Impure beryllium compounds are mainly represented by the
beryllium ores bertrandite and beryl, and numerous beryllium
alloys, some of which are listed in Table 2.
2.2 Physical and Chemical Properties
Some chemical and physical data of beryllium and selected
beryllium compounds are listed in Table 3.
Elemental beryllium has many unique properties (Krejci &
Scheel, 1966; Petzow & Aldinger, 1974; Ballance et al., 1978;
Newland, 1982; Reeves, 1986). It is the lightest of all solid and
chemically stable substances with an unusually high melting point.
It has a very low density and very high specific heat (1970 kJ/(kg x
K), 25 °C), heat of fusion (11.7 kJ/mol), sound conductance (12 600
m/s), and strength-to-weight ratio.
Beryllium is lighter than aluminium, but is more than 40% more
rigid than steel. It also has excellent electrical and thermal
conductivities. The only marked adverse feature is its relatively
high brittleness, which has restricted the use of metallic
beryllium to specialized applications.
Table 1. CAS chemical names and registry numbers, synonyms, trade names and atomic or molecular formulae of pure beryllium
and beryllium compoundsa
------------------------------------------------------------------------------------------------------------------------------
CAS chemical name CAS registry number Synonyms and trade names Formula
------------------------------------------------------------------------------------------------------------------------------
Beryllium 7440-41-7 Beryllium-9; glucinium Be
Acetic acid, beryllium salt 543-81-7 Beryllium acetate; beryllium acetate normal Be(C2H3O2)2
Hexakis[acetato-0:0]- 19049-40-2 Beryllium acetate, basic; beryllium oxide Be4O(C2H3O2)6
oxotetraberyllium acetate
Bis[carbonato-(2-)]dihydroxy- 66104-24-3 Beryllium carbonate; beryllium carbonate, (BeCO3)2 x Be(OH)2
triberyllium basic; beryllium oxide carbonate
Beryllium chloride 7787-47-5 Beryllium dichloride BeCl2
Beryllium fluoride 7787-49-7 Beryllium difluoride BeF2
Beryllium hydroxide 13327-32-7 Beryllium dihydroxide; beryllium hydrate Be(OH)2
Beryllium oxide 1304-56-9 Beryllia; beryllium monoxide; Thermalox BeO
Phosphoric acid, beryllium 13598-15-7 Beryllium phosphate; beryllium hydrogen BeHPO4
salt (1:1) phosphate
Phenakite 13598-00-0 Beryllium silicate; beryllium silicic acid; Be2SiO4
orthosilicate
Sulfuric acid, beryllium 13510-49-1 Beryllium sulfate BeSO4
salt (1:1)
Silicic acid, beryllium zinc 39413-47-3 Zinc beryllium silicate Exact composition unknown or
salt undetermined
------------------------------------------------------------------------------------------------------------------------------
a Adapted from: IARC (1980).
Table 2. CAS chemical names and registry numbers, synonyms, trade names, beryllium content and
molecular formulae of beryllium ores and alloysa
--------------------------------------------------------------------------------------------------
CAS chemical CAS Synonyms and trade names Composition Formula
name registry
number
--------------------------------------------------------------------------------------------------
Bertrandite 12161-82-9 Bertrandite; 42.1 % BeO; 4BeO x 2SiO2 x H2O
[Be4(H2Si2O9)] beryllium silicate 50.3 % SiO2;
hydrate 7.6 % water
Beryl 1302-52-9 Beryl ore; beryllium 10-13 % BeO; 3BeO x Al2O3 x 6SiO2
[Be3(AlSi3O9)2] aluminium silicate; 16-19 % Al2O3;
beryllium alumino- 64-70 % SiO2
silicate 1-2 % alkali metal
oxides; 1-2 % iron
and other oxides
Aluminum 12770-50-2 Beryllium-aluminium 62 % Be; -
alloy, Al, Be alloy; alumin(i)um- 38 % Al
beryllium alloy; Lockalloy
Copper alloy, 11133-98-5 Beryllium-copper- 0.3-2.0 % Be; -
Cu, Be alloy; beryllium 96.9-98.3 % Cu;
copper 0.2 % min. Ni
and Co; 0.6 % max.
Ni, Fe, and Co;
Nickel alloy, 37227-61-5 Beryllium nickel 2-3 % Be; -
Ni, Be alloy; nickel- up to 4 %
beryllium alloy other additives
rest: Ni
--------------------------------------------------------------------------------------------------
a Adapted from: IARC (1980).
Table 3. Physical and chemical properties of beryllium and selected beryllium compoundsa
---------------------------------------------------------------------------------------------------------
Chemical name Atomic/ Melting- Boiling- Density Crystal system Solubility
molecular point (°C) point (g/cm3)
mass (°C)
---------------------------------------------------------------------------------------------------------
Beryllium 9.01 1278 ± 5 2970 1.85 alpha-close-packed insol. cold H2O;
(5 mm Hg) (20 °C) hexagonal, sl. sol. hot H2O;
beta-body-centred sol. dil. acids
cubic and alkalies
Beryllium 127.10 300 - - plates insol. cold H2O, ethanol
acetate (dec.) and other common organic
solvents; slow hydrolysis
in boiling-water
Beryllium 79.92 405 520 1.899 needles very sol. H2O, ethanol
chloride (25 °C) and diethyl ether;
sl. sol. benzene and
chloroform
Beryllium 47.01 544 1160 1.986 amorphous very sol. H2O; sol.
fluoride (800, subl.) (25 °C) H2SO4 and ethanol
Beryllium 43.03 - - 1.92 powder or very sl. sol. H2O and
hydroxide crystals dil. alkali; sol. hot
conc. NaOH and acids
Beryllium 133.03 60 - - deliquescent very sol. H2O and
nitrateb crystalline mass alcohol
Beryllium 25.01 2530 ± 30 3900 3.01 hexagonal 0.2 mg/litre H2O; sol.
oxide conc. H2SO4
Beryllium 105.07 550-600 - 2.443 - insol. cold H2O;
sulfate (dec.) converted to
tetrahydrate in hot water
Beryllium 177.14 100 400 1.713 tetrahedric 425 g/litre H2O; insol.
sulfate (-2H2O) (-4H2O) crystalls ethanol; sl. sol. conc.
tetrahydrate H2SO4
---------------------------------------------------------------------------------------------------------
a Adapted from: IARC (1980), unless otherwise specified. b Windholz (1976).
conc. = concentrated; dec. = decomposition; dil. = dilute; insol. = insoluble; sl. = slightly;
sol. = soluble; subl. = sublimation.
Beryllium occurs naturally only as the 9Be isotope; 4 unstable
isotopes with mass numbers of 6, 7, 8, and 10 have been identified.
Because of its low atomic number, beryllium is very permeable to
X-rays. The neutron emission upon alpha-bombardment is the most
important of its nuclear physical properties, and beryllium can be
used as a neutron source. Moreover, its low neutron absorption
properties and its high-scattering cross-section determine its
characteristics as a suitable moderator and reflector of structural
material in nuclear facilities; while most other metals absorb
neutrons from the fission of nuclear fuel, beryllium atoms only
reduce the energy of such neutrons and reflect them back into the
fission zone.
The chemical properties of beryllium differ considerably from
those of the other alkaline earths, but it has a number of chemical
properties in common with aluminium (Krejci & Scheel, 1966; Petzow
& Aldinger, 1974; Reeves, 1986). Beryllium shows a very high
affinity for oxygen; on exposure to air or water vapour, a thin
film of beryllium oxide (BeO) forms on the surface of the bare
metal, providing the metal with a high resistance to corrosion.
Like aluminium, beryllium oxide (BeO) is amphoteric. The very
stable surface film also renders the metal resistant to water and
cold oxidizing acids. Dichromate in water enhances this resistance
by forming a protective film of chromate, similar to that formed on
aluminium. In powder form, beryllium is readily oxidized in moist
air and burns, because of the high entropy of formation of BeO
(23 x 103 kJ/kg), with a temperature of about 4500 °C, when ignited
in oxygen.
Beryllium powder reacts with fluorine at room temperature, and
with chlorine, bromine, iodide, sulfur, and the vapour of selenium
or tellurium to a significant extent only at elevated temperatures
(Petzow & Aldinger, 1974). From about 900 °C, nitrogen and ammonia
react violently with beryllium to form beryllium nitride (Be3N2).
No reaction takes place with hydrogen, even at high temperatures.
Melted beryllium reacts with most oxides, nitrides, sulfides, and
carbides. Because of its amphoteric character, beryllium is
dissolved by dilute acids and alkalis.
Cationic beryllium salts are hydrolysed in water and react to
form insoluble hydroxides or hydrated complexes at pH values
between 5 and 8, and beryllates above a pH of 8 (Reeves, 1986).
Beryllium oxide ("beryllia") is a colourless crystalline solid
or an amorphous white powder with an extremely high melting point,
high thermal conductivity, low thermal expansion, and high
electrical resistivity. It can either be moulded or applied as a
coating to a metal or other base; through the process of sintering
(1480 °C), a hard compact mass with a smooth glassy surface is
formed (Krejci & Scheel, 1966). The ceramic properties of sintered
beryllium oxide make it suitable for the production or protection
of materials used at high temperatures in corrosive environments.
A detailed review of the properties of beryllium compounds is
given by Krejci & Scheel (1966).
The use of beryllium in alloys is based on a combination of
outstanding properties that are conferred on other metals (Petzow &
Aldinger, 1974). Low density combined with strength, high melting
point, resistance to oxidation, and a high modulus of elasticity
make beryllium alloys suitable as light-weight materials that must
withstand high acceleration or centrifugal forces. Their
advantages over steel include greater resistance to corrosion,
higher electrical and thermal conductivities, greater strength, and
non-magnetic and non-sparking characteristics. Magnesium alloys
containing 0.1% beryllium have a markedly reduced risk of
combustion.
Most metals form very brittle intermetallic compounds with
beryllium. This and the low solubility of most elements in solid
beryllium are the reasons that beryllium-rich alloys have not
played a significant role. The only alloy with a high beryllium
content is lockalloy containing 62% beryllium and 38% aluminium.
Lockalloy has a high modulus of elasticity and low density with
reasonable ductility. Aluminium does not form beryllides. Other
alloys contain up to 3% beryllium (Petzow & Aldinger, 1974; IARC,
1980).
Of the intermetallic compounds, the beryllides of niobium,
tantalum, titanium, and vanadium are gaining interest in the
aerospace industry (Stokinger, 1981). Their properties include
high strength at elevated temperature and good thermal conductivity
and oxidation resistance, combined with densities that are lower
than those of refractory metals and many ceramics. The most
adverse feature of beryllides is their limited plastic
deformability (Walsh & Rees, 1978).
2.3 Analytical Methods
Methods for sampling, sample preparation, and the determination
of beryllium have been reviewed by Drury et al. (1978) and Delves
(1981). Since a detailed review of all the analytical procedures
is beyond the scope of this document, only a brief overview is
provided, including a summary of methods for the sampling and
determination of beryllium in various matrices (Table 4).
2.3.1 Sampling procedure and sample preparation
2.3.1.1 Sampling
Since most environmental samples contain only trace amounts of
beryllium, the proper collection and treatment of samples, before
analysis, is essential.
Beryllium in air is sampled by means of high-volume samplers
using low-ash cellulose fibre, cellulose ester, or fibreglass
papers as filters for non-volatile contaminants, and liquid- or
solid-filled scrubbers or cold traps to collect volatile forms of
beryllium. In the USSR, air sampling is performed on filters made
of polyvinyl-chloride fibres plunged in filter-supporters (Izmerov,
1985).
Table 4. Analytical methods for beryllium and beryllium compounds
--------------------------------------------------------------------------------------------------------------------------------
Medium Sampling method Analytical method Detection limit Comments Reference
--------------------------------------------------------------------------------------------------------------------------------
Air
Air Collect particulates with glass Gas chromatography 0.04 pg/sample No interference with Ross & Sievers
fibre filter; digest ashed filter with electron- several other metals; (1972)
in boiling HCl and HNO3 refluxing capture detection relatively rapid
for 3 h; add EDTA-buffer solution (40 min); relatively
and NaOH to pH 5.5-6.0; add inexpensive chromatograph;
benzene solution of trifluoro- applicable for routine
acetylacetone; decant chelate; analysis of ultratrace
wash with NaOH concentrations (0.1 ng/m3)
Air Ash glass fibre filter strips; Optical emission 5.3 µg/ml Scott et al.
add HNO3/HClO4 containing indium spectrometry (1976)
and yttrium; reflux; concentrate;
add HNO3; centrifuge; add LiCl2
solution
Air Dissolve glass fibre filter in Atomic absorption 2.5 ng/m3 Zdrojewski et
hydrofluoric acid; add HNO3; spectrophotometry al. (1976)
boil; dilute Graphite furnace 0.05 ng/m3
atomic absorption
spectrophotometry
Air Extract filter with H2SO4; add Spectrophotometry 1 ng/ml sample Inexpensive Mulwani & Sathe
chrome Azurol S, gum arabic (605 nm) (1977)
solution and EDTA; adjust to pH
2; add cetylpyridinium bromide
and hexamine solution; adjust to
pH 5
Air Collect particles on filter; Emission spectro- 3.6 ng/filter Rapid, near real-time Cremers &
no sample preparation required scopy using laser- (32 mm diameter, method (3-5 min); due to Radziemski
induced breakdown for particles particle size dependence (1985)
spark 0.5-5 µm in and interferences, only
diameter) semi-quantitative
Air Pass air through mixed cellulose Graphite-furnace 5 ng/sample Identical with official IARC (1986)
ester membrane filter via personal atomic absorption NIOSH method; suitable
sampling pump; digest filter in spectrophotometry for working range 0.5-10
HNO3/H2SO4; evaporate to dryness; µg/m3 for a 90-litre air
dissolve in 2%-NaOH/3%-H2SO4 sample
--------------------------------------------------------------------------------------------------------------------------------
Table 4. (contd.)
--------------------------------------------------------------------------------------------------------------------------------
Medium Sampling method Analytical method Detection limit Comments Reference
--------------------------------------------------------------------------------------------------------------------------------
Biological samples
Urine Add HNO3 and heat to dryness; Atomic absorption 2 µg/litre Bokowski (1968)
concentrate by adding NH4OH to spectrometry,
pH 1.5, EDTA, acetylacetone, nitrous oxide-
NH4OH to pH 7; separate in acetylene flame
funnel; centrifuge; draw off
lower layer
Organic Digest sample by low temperature Gas chromatography 10 pg/sample Suitable for trace levels Kaiser et al.
materials ashing or pressure decomposition with electron- (< 1 g) in limited amounts of (1972)
(blood, with HNO3/HF in teflon tube; capture detection organic materials
tissue, eliminate interfering elements
food, with EDTA; add trifluoroacetyl-
sewage, acetone in benzene; concentrate
mud, etc. by evaporation
Organic Digest sample in teflon tube Flameless atomic 0.6 µg/litre Stiefel et al.
materials under pressure; add EDTA - and absorption (for 1-ml urine (1976)
(blood, acetyl acetone; separate Be- spectrometry; sample)
muscle, complex by liquid-liquid graphite tube
urine, extraction with benzene treated with
etc.) ZrOCl2 to increase
Be-signal
Organic Wet-ash dried tissue in HNO3/ Fluorescence Not specified Used to determine Wicks & Burke
materials HClO4 in platinum dish; add EDTA spectrometry Standard Reference (1977)
and NH4OH to pH 7-8; add Materials (SRM)
acetylacetone; extract with
chloroform; add cyclohexane-
diammine-tetraacetic acid and
2-hydroxy-3-napthoic acid reagent
Biological Digest sample in HNO3/HClO4; Graphite-furnace 1 µg/kg Hurlbut (1978)
tissues evaporate; dissolve in HNO3 atomic absorption
(hair, containing lanthanum spectrometry
fingernail,
faeces)
--------------------------------------------------------------------------------------------------------------------------------
Table 4. (contd.)
--------------------------------------------------------------------------------------------------------------------------------
Medium Sampling method Analytical method Detection limit Comments Reference
--------------------------------------------------------------------------------------------------------------------------------
Biological samples (contd.)
Urine Add HNO3 containing lanthanum Graphite-furnace 0.01 µg/litre Lanthanum enhanced signal Hurlbut (1978)
or add HNO3 and excess NH4OH; atomic absorption and masked various cations
centrifuge; decant solution; heat spectrometry
Lung Digest dried sample in HNO3/ Graphite-furnace Not specified; Accuracy proved with Baumgardt et
tissue HClO4; heat to dryness and atomic absorption reported range: reference material and by al. (1986)
dissolve residue in HNO3 spectrometry 0.002-0.03 µg/ comparing with other
g dry weight analytical methods
Water
Fresh Acidify with HNO3 to stabilize Graphite-furnace 0.06 µg/litre Used to analyse Standard Epstein et al.
water solution atomic absorption Reference Material (1978)
spectometry
Graphite-furnace 2 µg/litre
atomic emission
spectrometry
Sea water Acidify with HCl; add Gas chromatography 18 pg/kg Precision: 5.5% at Measures &
trifluoroacetylacetone; extract with electron 180 pg/kg Edmond (1982)
beryllium complex with benzine capture detection
--------------------------------------------------------------------------------------------------------------------------------
Water samples should be collected in borosilicate glass or
plastic containers. It is important to adjust the pH to 5, or
below, to prevent losses due to adsorption of beryllium on the
surface of containers. Particulate matter should be filtered out
and analysed separately.
Urine samples are also acidified and can be preserved by adding
a 37% formalin solution (Keenan & Holtz, 1964). Precautions must
be taken to avoid contamination of the urine sample during
collection at the work-place. Animal tissues and vegetable matter
can also be preserved by adding formalin, or by cooling.
[Formaldehyde is irritant, may cause sensitization, and is a
possible human carcinogen.] The use of formalin is discouraged in
multielemental analyses, as this preservative contains large
amounts of contaminants. Instead, immediate freezing of the
samples and storage below -15 °C is recommended (Katz, 1985).
2.3.1.2 Sample decomposition
Organic matter, including air particulate filters, must be
destroyed to free the beryllium contents. This is accomplished, by
wet digestion using different mixtures of nitric, sulfuric, and
perchloric acid, or by dry ashing.
The NIOSH method for the determination of beryllium in air
involves the digestion of cellulose ester membrane filters in a
mixture of nitric and sulfuric acids (NIOSH, 1984).
Soft tissue and small bone samples can be decomposed by
covering the sample with concentrated nitric acid and repeatedly
heating to dryness. The dried (400 °C) residue can then be
analysed. Large bone samples are dried to constant weight at
105 °C and dry ashed in a muffle furnace by raising the temperature
gradually to 500 °C and heating for several hours. The ash residue
is extracted with hydrochloric acid (Drury et al., 1978).
Kingston & Jassie (1986) described the use of microwave energy
for the acid digestion of organic samples as a time-saving and
reliable method.
2.3.1.3 Separation and concentration
Several techniques are used to concentrate or separate
beryllium from interfering elements, prior to analysis (Drury et
al., 1978). Precipitation of beryllium as the phosphate,
hydroxide, or organic complex is only recommended for the
separation of macro quantities of beryllium from small amounts of
impurities. Alternatively, it can be coprecipitated with calcium,
manganese, titanium, and iron phosphates, and with aluminium and
iron hydroxides. However, in both cases, considerable losses may
occur.
In contrast to precipitation, solvent extraction can be used
for micro quantities of beryllium. Organic solvents, such as
benzene, chloroform, or carbon tetrachloride, containing a
beryllium complexing agent, are added to aqueous solutions in
which cationic impurities have been complexed with
ethylenediaminetetraacetic acid. The latter does not complex
beryllium. After separating the two solvents, the organic phase,
which contains the beryllium, is either further processed or
directly used in analysis (Drury et al., 1978).
Interfering substances can also be removed by ion exchange
techniques, using either cation or anion exchangers, and by
electrolysis with a mercury cathode.
2.3.2 Detection and measurement
Older methods used up to the 1960s included spectroscopic,
fluorometric, and spectrophotometric techniques. The main
deficiency of spectrophotometric methods lies in the non-
specificity of the complexing agents used to form coloured
complexes with beryllium. The limit of detection with these
methods is 100 ng Be/sample (Fishbein, 1984). The fluorometric
method, which is based on fluorescent dyes, preferably morin, has a
very low limit of detection of 0.02 ng Be/sample; its sensitivity
is only exceeded by that of the gas chromatographic method.
However, fluorometry may be subject to many errors, unless
several time-consuming and cumbersome processing steps are applied
prior to analysis. Emission spectroscopy is the most satisfactory
method, in terms of specificity and sensitivity. Thermal or
electrical excitation of the samples, which must be highly
concentrated, is accomplished by the use of a direct or alternating
current arc, and alternating current spark, with limits of
detection in the range of 0.5 - 5.0 ng Be/sample (Drury et al.,
1978; Fishbein, 1984).
Atomic absorption spectrometry is a rapid and very convenient
method for the analysis of environmental samples. The limit of
detection for the flame technique is 2 - 10 ng/ml, or lower when
pre-analysis concentration is employed (Bokowski, 1968). The
flameless method is much more sensitive. Hurlbut (1978) achieved
detection limits of 1 ng/g for faecal, hair, and fingernail samples
and of 0.01 ng/ml for urine samples. Addition of lanthanum was
found to enhance the absorption signal and eliminate interference
by various cations. Stiefel et al. (1980b) provided a detection
limit of 0.01 ng/g for immunoelectrophoretic blood fractions.
Using graphite-furnace atomic absorption spectrophotometry, the
NIOSH procedure for the determination of beryllium in air is
recommended for a working range of 0.05 - 1.0 µg/sample or
0.5 - 10.0 µg/m3 of air for a 90-litre sample (NIOSH, 1984).
Inductively coupled plasma atomic emission spectrometry has
been introduced to determine beryllium directly in a variety of
biological and environmental matrices (Schramel & Li-Qiang, 1982;
Wolnik et al., 1984; Awadallah et al., 1986; Caroli et al., 1988).
This method is superior to the previous method, because of its high
sensitivity and low level of interferences.
Owing to its high sensitivity and specificity, gas
chromatography is also used for determining beryllium in
environmental and biological media, particularly at ultratrace
levels. To convert beryllium into a volatile form, it is commonly
chelated with trifluoroacetylacetone and injected into the
chromatographic column. Using an electron-capture detector, Taylor
& Arnold (1971) determined beryllium in human blood with a
detection limit of 0.08 pg Be/sample. When combined with mass
spectrometry, sensitivities in the range of 0.04 - 10 pg Be/sample
were achieved (Wolf et al., 1972). Ross & Sievers (1972) developed
a routine method for environmental air analysis. At a limit of
detection of 0.04 pg Be/sample, beryllium concentrations in the
range of 0.49 - 0.6 ng Be/m3 could be determined. Because of its
carcinogenic properties, a safer alternative to benzene should be
considered as a solvent for trifluoroacetylacetone.
In the USSR, a photometric method is used to determine
beryllium in the air, with a sensitivity of 0.005 µg/sample
(Krivorutchko, 1966). Using gas chromatography, a sensitivity of
1.5 x 10-5 µg/sample is achieved (Yavorovskaya & Grinberg, 1974).
By successive treatment of the samples with water, 5% HCl, and
fusing with potassium fluoride, the differential determination of
water-soluble salts, beryllium metal, and its oxide is possible
(Naumova & Grinberg, 1974).
Other analytical techniques, such as polarography, enzyme
inhibition, and various types of activation techniques, have been
used, but do not play a major role in routine analysis (Drury et
al., 1978). Laser ion mass analysis is a promising technique for
the identification of beryllium in tissue sections (Jones Williams
& Kelland, 1986). Cremers & Radziemski (1985) used the laser-
induced spark technique to develop a near real-time method for
monitoring airborne beryllium concentrations.
3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1 Natural Occurrence
Beryllium is the 35th most abundant element in the earth's
crust, with an average content of about 6 mg/kg (Mason, 1952). It
occurs in rocks and minerals at concentrations of between 0.038 and
11.4 mg/kg (Drury et al., 1978). More than 40 minerals with
beryllium as the main constituent are known. Most beryllium
minerals were probably formed during the cooling of granitic
magmas, which led to an accumulation of crystallization products,
usually in association with quartz (Beus, 1966). Thus, the
beryllium content generally increases with increasing contents of
silica and alkalis. The most highly enriched beryllium deposits
are found in granitic pegmatites, in which independent beryllium
minerals crystallize (Wedepohl, 1966).
Only two beryllium minerals are of economic significance.
Beryl, an aluminosilicate, is mined in Argentina, Brazil, China,
India, Portugal, the USSR, and in several countries of southern and
central Africa (US Bureau of Mines, 1985a). Beryl contains up to
4% beryllium. In its purest gem quality, it occurs as emerald
(chromium-containing beryl), aquamarine (iron-containing beryl),
and as some semi-precious stones.
Although bertrandite contains less than 1% beryllium, it became
economically important in the late 1960s, because its processing
to beryllium hydroxide (section 3.2) is highly efficient.
Bertrandite, mined at Spor Mountain, Utah, USA, accounts for about
85% of the US consumption of beryllium ore (US Bureau of Mines,
1982). The total world reserves of beryllium that can be recovered
by mining are estimated at 200 000 tonnes (Petzow & Aldinger,
1974).
Clays and residual minerals contain most of the beryllium of
the original rocks from which they have been formed by weathering.
Clay soils contain between 2 and 5 mg Be/kg, while sandstones
contain less than 1 mg/kg and limestones, much less than 1 mg/kg
(Griffitts et al., 1977).
The most important source of environmental beryllium is the
burning of coal. It can be found in the ash of many coals at
concentrations of about 100 mg/kg (Griffitts et al., 1977).
Globally, coals contain average concentrations of between 1.8 and
2.2 mg/kg dry weight (US EPA, 1987). Coal samples from Australia,
the Federal Republic of Germany, Norway, Poland, the United
Kingdom, USA, and USSR showed concentrations of between < 5 and
15 mg Be/kg (Lövblad, 1977). Mineral oils contain up to 100 µg
Be/litre (Drury et al., 1978). The occurrence of beryllium in coal
and mineral oil is most probably the result of beryllium
accumulation in the precursor plants.
The beryllium contents of natural waters and unpolluted air are
very low (Fishbein, 1981) (section 5.1.1).
3.2 Man-Made Sources
3.2.1 Production levels and manufacture
3.2.1.1 Production levels
Beryllium production started in some industrialized countries
around 1916 (Petzow & Aldinger, 1974). In the early 1930s, it
gained commercial importance following the discovery that
beryllium-copper alloys were extraordinarily hard, resistant to
corrosion, non-magnetic, did not spark, and withstood high
temperatures. In addition, because of its nuclear and thermal
properties and high specific modulus, beryllium metal proved
attractive for nuclear and aerospace applications, including
weapons. This is the main reason that reliable data on the
production and consumption of beryllium are scarce and incomplete.
Moreover, considerable fluctuations in beryllium supply and demand
result from sporadic government programmes in armaments, nuclear
energy, and aerospace. For example, the beryllium demand in the
USA, created by the programme for the development of the atomic
bomb (Manhattan Project), was about equivalent to the total world
demand up to 1940 (Newland, 1982).
World production, excluding the USA, parallelled the
fluctuations of the beryllium market with 222 tonnes produced in
1965, 320 tonnes in 1969, and 144 tonnes in 1974. Data on US
production are now available and the world production of beryllium
can be characterized as shown in Table 5. Including its production
from bertrandite, the USA appears to be the world's largest
producer of beryllium raw materials. Estimated world production of
beryllium minerals was between 8873 and 10335 tonnes in the period
1980 - 84, which corresponds to between 355 and 413 tonnes of
beryllium.
Table 5. World mine production of beryllium (tonnes)a
-------------------------------------------------------------------
Country 1980 1981 1982 1983 1984
-------------------------------------------------------------------
Argentina 1.4 0.3 0.3 1.1 0.7
Brazil (exports) 24.2 37.6 46.8 55.2 55.2
Madagascar 0.4 0.4 0.4 0.4 0.4
Mozambique 0.9 0.8 0.7 0.7 0.7
Portugal 0.8 0.8 0.8 0.8 0.8
Rwanda 4.8 2.6 3.0 1.4 1.6
South Africa, Republic of - 5.4 2.6 1.0 -
USA 298.0 293.4 218.0 266.6 241.2
USSR 80.0 80.0 80.0 84.0 84.0
Zimbabwe 0.4 1.8 2.3 2.2 2.2
Total 410.9 423.1 354.9 413.4 386.8
-------------------------------------------------------------------
a Adapted from: US Bureau of Mines (1985a). Data calculated from
beryl ore production figures assuming a beryllium content of 4%.
Production industries exist only in Japan, the USA, and the
USSR. In other countries, the imported pure metal, alloys, or the
ceramic beryllium oxide are processed to end-products (Preuss &
Oster, 1980).
The doubling of capacity for beryllium-copper strip has been
reported by one US producer, to meet the increasing use of this
material in electronic devices (US Bureau of Mines, 1985a). Demand
for beryllium was expected, in 1986, to increase at an average
annual rate of about 4%, up to 1990 (US Bureau of Mines, 1986).
3.2.1.2 Manufacturing process
The first step in the production of pure beryllium metal or
beryllium compounds involves the extraction of a concentrate of
crystals of beryllium ores by manual selection or, where conditions
warrant, by mechanized mining methods (US Bureau of Mines, 1985b).
Two commercial methods are used to process beryl to beryllium
hydroxide (Petzow & Aldinger, 1974; Stokinger, 1981; Reeves, 1986).
In the fluoride process, beryl is sintered together with sodium
silicofluoride, or the less expensive sodium fluoroferrate, at
700 - 800 °C to convert beryllium oxide to a water-soluble salt
(Na2BeF4). This is then leached with water and precipitated from
the purified solution with caustic soda as beryllium hydroxide.
The sulfate process involves the alkaline or heat processing of
beryl and addition of strong sulfuric acid to the fused, quenched,
and ground minerals to extract the sulfates of beryllium,
aluminium, and other impurities. Following purification of this
solution the beryllium sulfate (BeSO4) is precipitated as the
hydroxide.
A less complicated procedure has been developed to process the
bertrandite ore. The so-called SX-carbonate-process makes caustic
pretreatment redundant and involves the direct leaching of
beryllium sulfate with sulfuric acid and subsequent precipitation
of beryllium hydroxide, which has a comparable high degree of
purity (Petzow & Aldinger, 1974).
Beryllium hydroxide is the starting material for the production
of beryllium, beryllia, and beryllium alloys. For further
processing, it is ignited to form the oxide (BeO) or converted to
the fluoride (BeF2). By means of the thermal reduction of BeF2
with other metals, mainly magnesium, beryllium metal is obtained,
which can be further processed by furnace, by electrolytic
refining, or by powder-metallurgical techniques.
The commercial manufacture of copper-beryllium alloys, which
are the most important beryllium alloys, involves melting together
virgin copper scrap, pure cobalt or a copper-cobalt master alloy,
and a copper-beryllium master alloy containing about 4% beryllium
(Ballance et al., 1978). The copper-beryllium master alloy is
produced by an arc-furnace method in which beryllium oxide is
reduced by carbon, in the presence of molten copper.
3.2.1.3 Emissions during production and use
The emissions of atmospheric beryllium in the USA are
summarized in Table 6. Natural emissions are negligible compared
with man-made emissions. At present, coal combustion in power
plants is a main source of beryllium emission. The application of
advanced dust emission control techniques could help to cut
beryllium emissions considerably. Because of the lack of data,
beryllium emissions into the atmosphere, resulting from the
military use of beryllium, cannot be accounted for. Although the
contribution of metallurgical sources to the overall beryllium
pollution is negligible (Table 6), locally elevated ambient
concentrations are likely to result from beryllium emissions during
production and processing, particularly in case of insufficient
control measures. Sources are beryllium extraction plants, ceramic
plants, foundries, machine shops, propellant plants, incinerators,
rocket-motor test facilities, and open-burning sites for waste
disposal (US EPA, 1973).
Table 6. Atmospheric beryllium emissions from different sources in the USA
------------------------------------------------------------------------------------------
Source Total US Emission Annual Percentage
production factor emission of total
(tonnes/year) (g/tonne) (tonnes/year) emission
------------------------------------------------------------------------------------------
Natural sourcesa
Windblown dust 8.2 x 106 0.6 5 2.48
Volcanic particles 0.41 x 106 0.6 0.2 0.10
-------------------
Total emission from natural sources 5.2 2.58
Man-made sources
Beryllium production and processing:
Mining negligiblec
Ore processinga 8 x 103 37.5 0.3 0.15
Be production negligiblec
Ceramic productionc 32 450 0.014 0.01
Cast iron productionc - - 3.6 1.79
Production of Be alloys and compoundsb - - 5 2.48
-------------------
Total emission from beryllium production 8.914 4.43
Combustion of fossil fuels
Coala 640 x 106 0.28 180 89.46
Fuel oila 148 x 106 0.048 7.1 3.53
---------------------
Total emission from combustion of fossil fuels 187.1 92.99
---------------------
Total beryllium emission from all sources 201.2 100.00
------------------------------------------------------------------------------------------
a Data from US Environmental Protection Agency (1987).
b Data from Drury et al. (1978).
c Data from US Environmental Protection Agency (1971).
Beryllium extraction and production plants emit many forms of
beryllium including beryl ore dust, beryllium and beryllium oxide
acid fume and dust, and a slurry of Be(OH)2 and (NH4)2BeF4 (US EPA,
1973). There are no recent data on emissions during the production
and processing of beryllium; according to earlier data from the US
EPA (1971), about 5 kg of beryllium for every 1000 tonnes of
beryllium processed are released into the ambient atmosphere during
beryllium production, resulting in a total emission of 6 kg in the
USA in the year 1968 (Drury et al., 1978). About 0.45 kg of
beryllium in the form of BeO-containing dusts, fumes, and mists are
emitted for every tonne processed to beryllia ceramics (US EPA,
1971), amounting to only 14.4 kg of the total US emission from this
source in 1968, assuming a production of 32 tonnes of beryllia
ceramics (10% of total beryllium demand in 1968). Major emissions
result from the cast iron production and fabrication of beryllium
alloys and compounds (Table 6). Beryllium emissions into the US
atmosphere from production-related sources added up to about 8.6
tonnes in 1968. This is only about 4.4% of the overall emission
from all sources.
As outlined in section 3.3, considerable amounts of beryllium
are used for military purposes, e.g., as rocket propellant. During
test flights, a major part of the beryllium will be released to the
atmosphere (Drury et al., 1978).
3.2.1.4 Disposal of wastes
Most of the beryllium scrap is resold to the producer;
recycling of most end-products is not worthwhile, because of their
small size and, usually, their low beryllium content (Griffitts et
al., 1977). They are either discarded along with other solid
wastes or salvaged for the copper in the alloy. In one instance,
beryllium-copper dust was dumped on to railroad tracks (OSHA,
Personal communication, 1989).
The major portion of beryllium waste results from pollution
control measures (Powers, 1976). The beryllium-containing dust
retained in scrubbers, electric sleeve filters, and multi-staged
purification devices is recycled into the production process, as
are liquid and solid wastes from hydrometallurgical and other
processes (Izmerov, 1985). Waste waters must be filtered before
discharging into the receiving waters. High efficiency is achieved
in sewage purification using filters made of "lavsan" to remove
metallic beryllium particles (Bobrischev-Pushkin et al., 1976).
Liquid, solid, or particulate waste that is too dilute to
recycle is buried in water-proof tailings ponds or in plastic
containers sealed in metal drums (US EPA, 1973). Often these
wastes are first burned to produce the chemically inert beryllium
oxide. The exhaust gases are scrubbed to retain particulates. The
disposal of scrap beryllium propellant involves underground
detonation and subsequent filtering of exhaust gases through
particulate air filters.
The flue gas cleaning system of industrial waste incineration
plants is designed to meet the national emission standards. For
instance, according to the Clean Air Act of the Federal Republic of
Germany, the sum of the emissions of beryllium, benz( a)pyrene, and
dibenzanthracene must not exceed 0.1 mg/m3 in the flue gases of
hazardous waste incinerators. Test runs showed an average
beryllium emission of 0.02 mg/m3 (STP) (Erbach, 1984).
3.2.2 Coal and oil combustion
A major source of atmospheric beryllium is the combustion of
fossil fuels, of which coal is the most important pollutant source.
The US EPA (1987) estimated that between 10 and 30% of the
beryllium contained in coal is emitted during the combustion
process. The remainder is retained by the captured fly ash. On
the basis of the average beryllium content of coal (1.4 mg/kg), the
combustion of 790 x 106 tonnes of coal in the USA during 1984
resulted in a total beryllium emission of 220 ± 110 tonnes/year,
while the consumption of 110 x 106 tonnes of fuel oil led to a
beryllium release of more than 7.1 tonnes. In 1981, the total
beryllium emission from fossil fuel combustion was 187.1
tonnes/year or about 93% of the combined emissions from all sources
(Table 6).
The emission factor is dependent on the efficiency of
mechanical and electrostatic precipitors of power plants. Thus,
improved dust emission control measures will cut the emission of
pollutants substantially. For instance, the average efficiency of
fly-ash collectors (electrostatic precipitators) in coal-power
plants in the Federal Republic of Germany is assumed to be between
97 and 99%. Hence, only 2.1 tonnes of beryllium were calculated to
be released into the atmosphere in 1981 from the combustion of
about 82 x 106 tonnes of coal (Brumsack et al., 1984).
3.3 Uses
Some of the most current applications of beryllium are listed
in Table 7.
Almost all of the beryllium produced is used as the free metal,
in the form of its alloys, or as the oxide. The various beryllium
compounds are primarily used as intermediates in the preparation of
beryllium metal or its alloys. Zinc beryllium silicate and
beryllium oxide were used widely in fluorescent tube phosphors,
until this application was abandoned in 1949 because of
considerable health hazards (Newland, 1982).
The main use of beryllium arises from the outstanding
properties that it confers on other metals; about 72% of the
beryllium produced is used in the form of beryllium-copper and
other alloys. About 20% is used as the free metal (Reeves, 1986)
and beryllium oxide accounts for the remaining 8%. In 1983, it was
estimated that about 65% of the US consumption was in the form of
beryllium alloys, about 15% in the oxide form, and the remainder in
the metal form (US Bureau of Mines, 1985b).
Table 7. Uses of beryllium metal, beryllium alloys, and beryllium oxide as related to
their propertiesa
------------------------------------------------------------------------------------------
Form Properties Technology Use
------------------------------------------------------------------------------------------
Beryllium High strength-to-weight Aerospace Windshield frames in US space shuttles
metal ratio Structural components in aeroplanes,
rockets, satellites, and space
vehiclesb
Antennae in data-gathering satellitesc
Turbine rotor blades
Heat sink Aircraft brakes
Heat shields for space vehicles and
missiles
Dimensional stability Inertial guidance systems
Other control systems
Mirror components of satellite optical
systems
High heat-of- Rocket propellant
combustion-to weight
ratio
Neutron source and Weapons Nuclear weapons
moderator
Moderator and reflector Nuclear Components of nuclear reactors
for neutrons
Nuclear fuel element as UBe13 alloyd
Neutron reflector in high-flux test
reactors
Transparency for X-rays X-ray and Windows in X-ray tubes and radiation
radiation detection devices
Coating for biological X-ray
microanalysisb
Transparency for X-rays Computer Ultrathin foil for X-ray lithography
Beryllium- Dimensional stability Aerospace Aircraft engine parts
copper
alloys
Beryllium- High strength; good Electronic Contacts
copper electrical and thermal Switches
alloys conductivity Circuit breaker parts
Fuse clips
High-frequency connector plugs
------------------------------------------------------------------------------------------
Table 7. (contd.)
------------------------------------------------------------------------------------------
Form Properties Technology Use
------------------------------------------------------------------------------------------
Beryllium- High strength Mechanical Springs
copper Bearings
alloys Gear parts
(contd.) Camera shutters
Golf club headse
Non-sparking Tools
High strength; good Others Injection moulds for plastics
thermal conductivity; Precision castings
dimensional stability Diaphragms
Welding electrodes
Beryllium- Aerospace Construction materials for aircraft
aluminium and spacecraftf
alloy
(Lockalloy)
Beryllium- High strength Electronic Springsf
copper- Good conductivity Switchesf
cobalt- Contactsf
alloyf,g Welding electrodes and holdersg
Mechanical Bushingsg
Bearingsg
Soldering iron tipsg
Others Nozzles for gas and oil burnersg
Plunger tips for die-casting machinesg
Beryllium- Higher thermal Aerospace Aircraft and spacecraft partsh
nickel- conductivity than
alloy beryllium-copper alloys Glass Various glass-moulding functionsf
Beryllium- Electronic Electrical connectorsf
nickel
alloy Others Springsf
Diamond drill bit matricesh
Watch balance wheelsh
Beryllium- Facilitated castability Dentistry Alternatives to gold alloys used for
nickel- High porcelain-metal crowns and bridgesi,k
chromium bond strength
alloy
Beryllium High thermal Aerospace Rocket-chamber-combustion liners
oxide conductivity, heat
capacity, and Electronic Electrical insulator
electrical resistivity Resistor coresh
------------------------------------------------------------------------------------------
Table 7. (contd.)
------------------------------------------------------------------------------------------
Form Properties Technology Use
------------------------------------------------------------------------------------------
Beryllium Ceramic properties Integrated circuit chip carriersh
oxide Radio, laser, and microwave tubesh
(contd.) Spark plugs
Other high-voltage electrical components
Moderator and reflector Nuclear Components of nuclear reactorsl
for neutrons
High thermal Others Mantels in gas lanternsm
conductivity
------------------------------------------------------------------------------------------
a Adapted from: Newland (1982), unless otherwise specified.
b Lupton & Aldinger (1983).
c Greenfield (1971).
d Stokinger (1981).
e OSHA (1989).
f Ballance et al. (1978).
g IARC (1980).
h Reeves (1986).
i Covington et al. (1985a).
k Bencko (1989).
l Boland (1958).
m Griggs (1973).
Most beryllium-copper alloys are used in parts that need
extraordinary hardness, such as bushings, bearings, springs,
electric contacts, and switches. A more recent use is the
manufacture of 1.8% beryllium-copper alloy golf club heads. Other
important applications include the manufacture of welding
electrodes and precision casting for optical and mechanical
recording instruments. Non-sparking tools made of beryllium-copper
alloys are convenient materials for use in explosive atmospheres,
e.g., in petroleum refineries.
Beryllium-aluminium alloys are gaining interest for use as
construction materials in aircraft and spacecraft technology
(Izmerov, 1985). Also, some intermetallic compounds of beryllium,
particularly the beryllides of niobium, tantalum, titanium,
vanadium, and the borides of beryllium are being considered for use
as structural materials for space vehicles (Stokinger, 1981).
Beryllium-nickel alloy is used in the place of beryllium-copper
alloy for high-temperature applications (Farkas, 1977). It also
has greater hardness than the copper alloy and is therefore used in
the production of components requiring this property, e.g., watch-
balance wheels.
Beryllium-containing alloys are increasingly used in dentistry
as alternatives to more expensive gold alloys. When added to
nickel-chromium alloys, beryllium (2% or less) facilitates
castability and increases the porcelain-metal bond strength
(Covington et al., 1985a). Apart from dental prostheses, beryllium
has also been found in the cement used to fix crowns and bridges,
as reported by Schönherr & Pevny (1985), but no data were given.
The applications of beryllium metal are mainly related to its
nuclear and thermal properties and high specific modulus
(Greenfield, 1971; Ballance et al., 1978). For many years, the
major application of beryllium in the form of thin sheets, was in
X-ray windows. Such windows are also used in Geiger proportional
and scintillation counters.
In the 1950s, beryllium and its oxide were believed to be
promising moderator and reflector materials for nuclear reactors.
However, because the shut-down of a graphite-moderated reactor is
much faster and because of the high cost of beryllium, nuclear
applications have been limited to test reactors and, probably, to
mobile reactors, as used in nuclear submarines. It is also assumed
that beryllium is used as reflector material in atomic bombs. The
development of beryllium-based cladding material for uranium
dioxide fuel was abandoned in the 1960s, because of the high costs
and brittleness of beryllium, which caused tube cracking
(Greenfield, 1971; Buresch, 1983).
A major application of beryllium is for aircraft and spacecraft
structural materials where a combination of light weight, rigidity,
dimensional stability, and good thermal characteristics is
demanded. The advantage of using beryllium in missiles and
spacecraft lies in its superiority, in this respect, over any other
metal or alloy. For instance, basic weights of 3-stage missiles
are reduced by 40%, compared with steel (Greenfield, 1971). Its
high modulus of elasticity and dimensional stability make beryllium
an excellent material for use in aircraft and spacecraft
instruments including inertial guidance devices and other control
systems using gyroscopes, gimbals, torque tubes, and high-speed
rotating elements.
Beryllium is also used as a heat sink for aircraft wheel brakes
and the heat shields of re-entry space vehicles and missiles, and
for scanning mirrors and large mirror components of satellite
optical systems (Ballance et al., 1978).
Since most of these applications of beryllium are for military
devices, no data concerning the demand for beryllium for the
various applications are available. There is almost a total lack
of information on the use of beryllium powder as solid rocket
propellant, although test flights of such rockets could contribute
considerably to local non-occupational exposure to atmospheric
beryllium. It is believed that beryllium is gaining interest as an
ideal rocket propellant in terms of high heat of combustion at low
weight. In these properties, it is superior to other solid and
chemically stable substances (Reeves, 1977; Krampitz, 1980). The
existence of a rocket propellant industry (Fishbein, 1981) is
indicative of the importance of beryllium for this application.
Owing to its high thermal conductivity and heat capacity
combined with high electrical resistivity, beryllium oxide has
major ceramic applications in electronics and micro-electronics,
where it is used as an electrical insulator in parts requiring
thermal dissipation. Metallized beryllia is used for the removal
of heat in semiconductor devices and integrated circuits (Walsh &
Rees, 1978). Its high transparency to microwaves renders beryllium
oxide suitable for use in microwave technology (Ballance et al.,
1978). The oxide of beryllium is also a component of mantles of
gas lanterns, one of the rare non-industrial applications (Griggs,
1973).
4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
Data concerning the fate of beryllium in the environment are
limited. Since the major source of atmospheric beryllium is coal
combustion, the most prevalent chemical form is probably beryllium
oxide, mainly bound to particles smaller than 1 µm. The residence
time of these particles in the atmosphere is about 10 days (US EPA,
1987). Beryllium returns to earth by wet and dry deposition in a
similar manner to other metals and on particles of comparable size
distribution (Kwapulinski & Pastuszka, 1983).
During the natural processes of weathering and formation of
sediments, beryllium resembles aluminium in that it is enriched in
clays, bauxites, recent deep-sea deposits, and other hydrolyzate
sediments (Newland, 1982).
Reactions of beryllium in solution and soil depend on the pH.
At environmental pH ranges of 4 - 8, beryllium oxide is highly
insoluble, thus preventing mobilization in soil. Beryllium is
strongly absorbed by finely dispersed sedimentary materials
including clays, iron hydroxides, and organic substances (Izmerov,
1985). Thus, very little is released into ground water, during
weathering. If beryllium oxide is converted to the ionized salts
(chloride, sulfate, nitrate) during atmospheric transport,
solubility upon deposition and, hence, mobility in soils would be
greatly enhanced, but this has not been reported in the literature.
Because of the low solubility of beryllium oxide and hydroxide
at pH levels commonly found in natural waters, only small amounts
of beryllium are found in the form of the chloride, fluoride,
chlorocarbonate, or organic complexes (Griffitts et al., 1977).
If beryllium is bioavailable in the soil matrices, it can be
assimilated by plants and, thus, enter the food chain. Beryllium
is classified as a fast-exchange metal, and could potentially
interfere with the transport of nutritive metals, such as calcium,
into eukaryotic cells (Wood & Wang, 1983). Although there is a
lack of data on beryllium levels in environmental organisms
representing high trophic levels, and on the fate of beryllium in
ecosystems, it is not believed to biomagnify within food chains to
an extent that would imply an important pathway to the consumer.
From the beryllium levels found (section 5.1.6.1), it appears
that plants take up beryllium in small amounts. However, some
species act as accumulators of beryllium. Hickory trees ( Carya
spp.) contain as much as 1 mg/kg dry weight (Griffitts, 1977).
Nikonova (1967) found up to 10 mg/kg in several plant species in
the South Urals (USSR). Tundra plants (Seward Peninsula, Alaska)
tend to accumulate beryllium from soils, if the soil content is at,
or below, 20 mg/kg; however, above 50 mg/kg, the plants cannot
absorb more (Sainsbury et al., 1968). Thus, plant ash may contain
greater amounts of beryllium than the soil.
Tolle et al. (1983) investigated beryllium accumulation by
plants grown on soil that had been treated with beryllium-
containing precipitator fly ash from a power plant. The beryllium
concentration in the soil was not reported. Beryllium uptake by
mixed-species crops of alfalfa, timothy, and oats, planted either
in agricultural microcosms or in field plots, did not differ from
that of control plants. Moreover, uptake by oat grains was
comparable to uptake by oat stalks, indicating that there was not
any selective enrichment in the grains. Kloke et al. (1984)
estimated that the transfer plant/soil coefficient for beryllium
was of the order of magnitude of 0.01 - 0.1, depending on the plant
species and soil properties.
The roots of barley, bean, tomato, and sunflower plants, grown
for 30 days in aerated nutrient solution containing undetermined
levels of the Be7 isotope, showed a radioactivity of between 29 717
and 66 968 cpm/g. From the corresponding values in the leaf, stem,
and fruit (146 - 910 cpm/g), it can be concluded that very little
beryllium is translocated to other plant parts (Romney & Childress,
1965). Leaves seemed to take up more beryllium than stems or
fruits.
As with other metals, beryllium contamination also occurs from
the wet and dry deposition of beryllium-containing particles on the
above-ground plant parts. Although beryllium levels in the leaves
of some species have been reported (section 5.1.6), there are no
data concerning the uptake of atmospheric beryllium into leaves.
No data are available on the trophic transfer of beryllium in
aquatic ecosystems.
5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1 Environmental Levels
5.1.1 Ambient air
The atmospheric background level of beryllium in the USA has
previously been reported to average less than 0.1 ng/m3 (Bowen,
1966) or 0.2 ng/m3 (Sussman et al., 1959). In a more recent
survey, the annual averages during 1977 - 81, at most monitoring
stations throughout the USA, were around the detection limit of
0.03 ng/m3 (US EPA, 1987). This agrees with the mean values of
0.03 - 0.06 ng/m3 found by Ross et al. (1977), at rural sites in
the USA, using a sensitive chelation-gas chromatographic method.
Since fossil fuel combustion contributes to the ubiquitous
occurrence of beryllium, particularly in the highly industrialized
northern hemisphere, these background levels reflect the overall
pollution from this source.
There appears to be a considerable range of reported values for
beryllium concentrations in urban air. The air of over 100 cities
in the USA, sampled in 1964 - 65, did not contain detectable
amounts of beryllium at a detection limit of 0.1 ng/m3 (Drury et
al., 1978). In the 1950s, beryllium concentrations of between 0.1
and 0.5 ng/m3 were found in major US cities, such as New York and
Los Angeles. The maximum level of beryllium in the air of more
than 30 metropolitan areas was 3 ng/m3 (Chambers et al., 1955).
The highest 24-h level measured in a 1977 survey in Atlanta,
Georgia, was 1.78 ng/m3. The annual averages, at urban monitoring
stations throughout the USA with levels exceeding 0.1 ng/m3, ranged
between 0.1 and 6.7 ng/m3, during 1981-86 (US EPA, 1987). Ross et
al. (1977) reported concentrations of beryllium in air particulates
of 0.04 - 0.07 ng/m3, at suburban sites, and 0.1 - 0.2 ng/m3, at
urban industrial sites, in Dayton, Ohio.
Using flameless atomic absorption spectrophotometry, Ikebe et
al. (1986) found an average of 0.042 ng/m3 in 76 air samples from
17 Japanese cities, collected between 1977 and 1980. The highest
values were found in Tokyo (0.222 ng/m3) and in an industrial area
in Kitakyushu (0.211 ng/m3).
Freise & Israel (1987) found annual mean values in Berlin
ranging between 0.2 and 0.33 ng/m3, for sectors with different wind
direction.
A concentration of 0.06 ng/m3 was measured in a residential and
office area as well as in the inner city area of Frankfurt (Federal
Republic of Germany), whereas a concentration of 0.02 ng/m3 was
measured in a rural area near Frankfurt (Mueller, 1979).
Before the introduction of control measures, atmospheric
beryllium concentrations were extremely high in the vicinity of
point sources. In the vicinity of a Pennsylvania (USA) processing
plant, a mean concentration of 15.5 ng/m3 and a maximum of 82.7
ng/m3 were reported. At various distances from the plant, the
average concentrations dropped from 28 ng/m3 at 0 - 800 m to about
6.6 ng/m3 at a distance of 1800 - 3200 m and to 1.4 ng/m3 further
away. During a partial plant shutdown, the beryllium level dropped
to 4.7 ng/m3, while a complete 2-week shutdown resulted in an
average of 1.5 ng/m3 (Sussman et al., 1959).
About 0.4 km from the stack of a beryllium emission source in
the USA, the beryllium concentration in air was 200 ng/m3; however,
at a distance of 16 km, it was below the detection limit (1 ng/m3)
(Eisenbud et al., 1949). The air level, 400 m from a beryllium
extracting and processing plant in the USSR that was not equipped
with emission control devices, averaged 1000 ng Be/m3; at 1000 m,
it was between 10 and 100 ng/m3. Between 500 and 1500 m from a
mechanical beryllium-finishing plant with operational filter
facilities, no beryllium was detected in the air (Izmerov, 1985).
Bobrischev-Pushkin et al. (1973, 1976) investigated the
atmospheric air conditions around a plant for the mechanical
treatment of beryllium. In accordance with health rules for
operations involving beryllium, the air emissions were subjected to
a multi-stage purification process using PVC fibre tissue as a
final filtering element. In 290 air samples taken at distances of
500, 900, 1000, and 1500 metres downwind from the plant, beryllium
could not be detected by gas chromatography (sensitivity 1.5 x 10-5
µg in the volume analysed).
Bencko et al. (1980) reported beryllium concentrations of
between 3.9 and 16.8 ng/m3 (average 8.4 ng/m3) in the vicinity of a
Czecho-slovakian power plant, situated at the edge of a town from
which the non-occupationally exposed group in this study was taken.
5.1.2 Surface waters and sediments
Beryllium concentrations in surface waters are usually in the
ng/litre range (Table 8). Levels reported for Australian rivers
ranged from not detectable to 0.08 µg/litre, with mean
concentrations of between 0.02 and 0.03 µg/litre (Meehan & Smythe,
1967). Although otherwise highly polluted, samples of the rivers
Rhine and Main (Federal Republic of Germany) contained beryllium
only at concentrations of < 0.005 - 0.02 µg/litre, with mean
values of 0.009 and 0.019 µg/litre, respectively (Reichert, 1974).
Higher levels were reported in the Rhine region in 1983 - 85 (IAWR,
1986): the mean values at two measuring stations were around 0.1
µg/litre, the maximum values were between 0.26 and 0.52 µg/litre.
Durum & Haffty (1961) analysed 15 major rivers in the USA and
Canada and found detectable amounts of beryllium in only 2 water
samples (< 0.06 µg Be/litre and < 0.22 µg Be/litre) out of 59.
Beryllium levels in seawater are ten times lower than those in
surface waters. In the Pacific Ocean, concentrations of 0.6
ng/litre (Merril et al., 1960) and 2 ng/litre (Meehan & Smythe,
1967) were reported. Data reported by Measures & Edmond (1982)
showed that still lower concentrations can be expected. In a
detailed profile analysis, the concentration of beryllium has been
shown to increase with depth. The mixed layer, up to about 500 m,
is characterized by a level of between 0.04 and 0.06 ng Be/litre;
the concentrations rise through the main thermocline to levels of
0.22 - 0.27 ng/litre (25 - 30 pmol/kg) in the deep and bottom
waters (2500 - 5900 m).
Table 8. Beryllium concentrations in surface waters
------------------------------------------------------------------------------------------
Number Surface water and Range mg/litre Reference
of location mean
samples
------------------------------------------------------------------------------------------
River
1 Lachlan (Farbes, Australia) 0.01 Meehan &
1 Macquarie (Bathurst, Australia) 0.01 Smythe (1967)
1 Nepean (Emu Plains, Australia) NDa
27 Woronara (Discharge Pt, Australia) 0.01-0.012 0.03
26 Woronara (Tolofin, Australia) 0.01-0.08 0.02
59 15 rivers in the USA and Canada ND-< 0.22b nsc Durum & Haffty (1961)
nsc Raw surface waters in the USA 0.01-1.22d 0.19 National Academy of
Sciences (1977)
nsc River Rhine (Federal Republic of < 0.005-0.011 0.009 Reichert (1974)
Germany)
nsc River Main (Federal Republic of 0.008-0.02 0.019
Germany)
nsc River Rhine (Netherlands) 0.36-0.58e 0.09 IAWR (1986)
Sea
1 Pacific Ocean - 0.002 Meehan & Smythe
1 Indian Ocean 0.001 (1967)
5 Pacific Ocean - 0.0006 Merril et al. (1960)
nsc Pacific Ocean, near Hawaii, depth - 0.00004 Measures & Edmond
40 m (1982)
------------------------------------------------------------------------------------------
a ND = not detected.
b Detected but less than figure indicated.
c ns = not specified.
d Beryllium was detected only in 5.4% of 1577 raw surface waters.
e Range of maximum values.
When several ground-water samples were analysed in the western
USA, beryllium was detected in only 3 highly acidic mine waters
(Griffitts et al., 1977). Ground-water samples from the Federal
Republic of Germany contained levels ranging from not detectable
(< 0.005 µg/litre) to 0.009 µg/litre with a mean of 0.008 µg/litre
(Reichert, 1974).
The beryllium contents of sediments correspond to those of soil
samples (section 5.1.3). Bottom sediments of lakes in Illinois,
USA, contained 1.4 - 7.4 mg/kg (Dreher et al., 1977). The mean
beryllium content of Tokyo Bay and Sagami Bay sediments (Japan) was
1.29 mg/kg (Asami & Fukazawa, 1985).
5.1.3 Soil
As outlined in section 3.1, beryllium is widely distributed in
soils at low concentrations. Geochemical surveys (e.g., US EPA
(1987)) suggested an overall average of about 6 mg/kg for beryllium
in the lithosphere as a whole. More specific data (Shacklette et
al., 1971) indicated lower levels for agricultural soils; 847
samples collected at a depth of 20 cm throughout the USA contained
between less than 1 and 7 mg beryllium/kg, averaging 0.6 mg/kg.
Only 12% of the samples exceeded 1.5 mg/kg. None were collected in
geological areas containing large deposits of beryllium minerals.
These areas are relatively rare, but they account for the overall
lithospheric average of 6 mg/kg.
The beryllium contents of uncontaminated Japanese soils were of
the same order of magnitude. Asami & Fukazawa (1985) analysed over
100 soil horizons from all over Japan and found a mean
concentration of 1.31 mg beryllium/kg. The beryllium contents of
the surface soils of paddy fields ranged from 1.10 to 1.95 mg/kg
and those of the subsoils, 0.88 - 1.95 mg/kg. Podzol and brown
forest soil contained between 0.01 and 2.72 mg/kg, with regional
differences. Mineral surface soils showed beryllium levels of
0.27 - 1.66 mg/kg. Beryllium distribution in the profiles of
forest soils reflected a leaching process; in all the profiles, the
beryllium contents generally increased with an increase in depth.
For example, beryllium contents of a yellowish brown forest soil
were as follows: 1.66 mg/kg in the topmost mineral layer
(A1-horizon, 0 - 9 cm), 2.39 mg/kg in the subsoil (B2-horizon,
17 - 30 cm), and 2.72 mg/kg in the layer below (C3-horizon, 48 - 58
cm). In some profiles, beryllium contents decreased again at
deeper horizons.
In some small and unpopulated areas in which rocks contained
unusually high levels of beryllium, the overlying soils also showed
relatively high beryllium concentrations. For instance, soils of
the beryllium district in the Lost River Valley, Alaska, contained
up to 300 mg beryllium/kg, with an average of 60 mg/kg (Shacklette
et al., 1971).
In the Federal Republic of Germany, an allowable concentration
of 10 mg/kg air-dried soil was proposed by Kloke et al. (1984) as a
guideline value for arable soils.
5.1.4 Food and drinking-water
Only limited data concerning the beryllium contents of foods
are available. Meehan & Smythe (1967), using a chemical analytical
method,