9.6 BERYLLIUM
Beryllium (Be) is one of the least-known environmental pollutants, and yet it is
one of the most toxic nonradioactive elements known. Its industrial threshold
limit value (TLV) is 2 mg/m
3 , the lowest for any particulates. (The TLV of a
toxicant is defined as the maximum concentration to which it is believed
healthy workers may be repeatedly exposed without ill effect, based on an 8hour working day.) The toxicity of Be in humans was described in the U.S. in
the 1940s, when more than 500 cases of Be disease were reported. Acute disease
occurred in Ohio among Be extraction and production workers, while chronic
disease was found in Massachusetts among workers manufacturing fluorescent
lamps containing beryllium-phosphor. The use of Be in fluorescent lamps was
discontinued in 1950. As a result, Be disease incidence has decreased
dramatically.
Be is estimated to make up about 0.0006% of earth’s igneous rocks. Of 28
minerals in which Be is a minor accessory constituent, beryl (beryllium
aluminum silicate, Be 3 Al 2 Si 6 O 18 ), with 14% BeO, is the chief source of Be, and
as such is the most important commercially. Be is also found in coal, in
amounts ranging from 0.1 to 1000 ppm.
9.6.1 SOURCES OF EXPOSURE
Exposure to Be compounds can occur within the production and manufacturing industries, as well as in housekeeping, maintenance, salvage, and solidwaste areas. Individuals working in any operations involving production of
airborne Be are at risk for developing Be disease. The major occupations at risk
of developing Be disease have changed since the first reports of cases in the
U.S. in the 1940s. Before 1950, exposure most commonly occurred in
fluorescent lamp manufacturing, atomic bomb research, and Be extraction
operations. After 1950, Be was replaced in fluorescent lamp production by a
calcium phosphor. However, Be has since been used in modern technologies,
including nuclear reactors, electronics equipment, guidance and navigation
systems, rocket parts, and heat shields. It is employed extensively as an alloying
agent for copper as it adds tensile strength, conductivity, and corrosion
resistance.
Chronic Be disease has been reported in people living in areas adjacent to a
plant or industry using the metal, suggesting neighborhood exposure from
plant discharges into the air. It has also been shown that families of Be workers
may also be exposed to the metal as a result of dust carried home on the
workers’ clothes. Between 1973 and 1980, 66 cases of chronic Be disease were
reported in the U.S., nearly half of these involved Be metal production. The
combustion of coal is considered the largest source of environmental Be
contamination. Some coal contains about 2.5 ppm, and oil contains about
0.8 ppm of Be. Atmospheric emission of Be from these sources has been
estimated to be above 1000 t annually.
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Ref: 4365 MING-HO YU Chap-009 Page: 141 135-148
Beryllium (Be) is one of the least-known environmental pollutants, and yet it is
one of the most toxic nonradioactive elements known. Its industrial threshold
limit value (TLV) is 2 mg/m
3 , the lowest for any particulates. (The TLV of a
toxicant is defined as the maximum concentration to which it is believed
healthy workers may be repeatedly exposed without ill effect, based on an 8hour working day.) The toxicity of Be in humans was described in the U.S. in
the 1940s, when more than 500 cases of Be disease were reported. Acute disease
occurred in Ohio among Be extraction and production workers, while chronic
disease was found in Massachusetts among workers manufacturing fluorescent
lamps containing beryllium-phosphor. The use of Be in fluorescent lamps was
discontinued in 1950. As a result, Be disease incidence has decreased
dramatically.
Be is estimated to make up about 0.0006% of earth’s igneous rocks. Of 28
minerals in which Be is a minor accessory constituent, beryl (beryllium
aluminum silicate, Be 3 Al 2 Si 6 O 18 ), with 14% BeO, is the chief source of Be, and
as such is the most important commercially. Be is also found in coal, in
amounts ranging from 0.1 to 1000 ppm.
9.6.1 SOURCES OF EXPOSURE
Exposure to Be compounds can occur within the production and manufacturing industries, as well as in housekeeping, maintenance, salvage, and solidwaste areas. Individuals working in any operations involving production of
airborne Be are at risk for developing Be disease. The major occupations at risk
of developing Be disease have changed since the first reports of cases in the
U.S. in the 1940s. Before 1950, exposure most commonly occurred in
fluorescent lamp manufacturing, atomic bomb research, and Be extraction
operations. After 1950, Be was replaced in fluorescent lamp production by a
calcium phosphor. However, Be has since been used in modern technologies,
including nuclear reactors, electronics equipment, guidance and navigation
systems, rocket parts, and heat shields. It is employed extensively as an alloying
agent for copper as it adds tensile strength, conductivity, and corrosion
resistance.
Chronic Be disease has been reported in people living in areas adjacent to a
plant or industry using the metal, suggesting neighborhood exposure from
plant discharges into the air. It has also been shown that families of Be workers
may also be exposed to the metal as a result of dust carried home on the
workers’ clothes. Between 1973 and 1980, 66 cases of chronic Be disease were
reported in the U.S., nearly half of these involved Be metal production. The
combustion of coal is considered the largest source of environmental Be
contamination. Some coal contains about 2.5 ppm, and oil contains about
0.8 ppm of Be. Atmospheric emission of Be from these sources has been
estimated to be above 1000 t annually.
14
Air Pollution – Particulate Matter
141
[16:52 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-009.3d]
Ref: 4365 MING-HO YU Chap-009 Page: 141 135-148