Beryllium is a metallic element. Pure beryllium is a hard, grayish metal. In nature, beryllium can be found in compounds in mineral rocks, coal, soil, and volcanic dust. Beryllium compounds have no particular smell. Beryllium occurs naturally in the earth's crust at concentrations ranging from 2-10 ppm. It is also released into the atmosphere from coal combustion at concentrations of ~0.01-0.1 ng/m3, most likely as beryllium oxide. Beryllium occurs in house dust, surface water, food, and soil. The general population is exposed to beryllium every day. Cigarette smokers can be exposed to nearly twice the amount of beryllium as nonsmokers. Beryllium compounds are commercially mined, and the beryllium purified for use in electrical parts, machine parts, ceramics, aircraft parts, nuclear weapons, and mirrors. Currently, beryllium has many industrial uses (e.g., in brake systems of airplanes, for neutron monochromatization, as window material for x-ray tubes, and in radiation detectors). The commercially important compound, beryllium oxide, is used in the electronics industry as a substrate for transistors and silicon chips, coil cores, and laser tubes.
Limited data indicate that the oral toxicity of beryllium is low in humans. No adverse effects were noted in mice given 5 ppm beryllium in the drinking water in a lifetime bioassay. In contrast, the toxicity of inhaled beryllium is well-documented. Humans inhaling "massive" doses of beryllium compounds may develop acute berylliosis. ATSDR estimated that, based on existing data, the disease could develop at levels ranging from approximately 2-1000 µg Be/m3. This disease usually develops shortly after exposure and is characterized by rhinitis, pharyngitis, and/or tracheobronchitis, and may progress to severe pulmonary symptoms. The severity of acute beryllium toxicity correlates with exposure levels, and the disease is now rarely observed in the United States because of improved industrial hygiene. Humans inhaling beryllium may also develop chronic berylliosis which, in contrast to acute berylliosis, is highly variable in onset, is more likely to be fatal, and can develop a few months to >=20 years after exposure.
Epidemiologic studies have suggested that beryllium and its compounds could be human carcinogens. Studies in workers exposed to beryllium, mostly via inhalation, have shown significant increases in observed over expected lung cancer incidences. The U.S. EPA, in evaluating the total database for the association of lung cancer with occupational exposure to beryllium, noted several limitations, but concluded that the results must be considered to be at least suggestive of a carcinogenic risk to humans. In laboratory studies, beryllium sulfate caused increased incidences of pulmonary tumors in rats and rhesus monkeys.
Based on sufficient evidence for animals and inadequate evidence for humans, beryllium has been placed in the EPA weight-of-evidence classification B2, probable human carcinogen.
The following is a presentation of the toxicity information associated with Beryllium.
Noncarcinogenic Health Effects
- The Oral Chronic Reference Dose is 2.00E-03 (mg/kg-day).
- The Oral Chronic Reference Dose has a modifying factor of 1.
- The Oral Chronic Reference Dose has an uncertainty factor of 300.
- The Oral Chronic Reference Dose is based on the Morgareidge et al. study from 1976.
- The Oral Chronic Reference Dose study target organ is small intestine.
- The Oral Chronic Reference Dose study critical effect is lesions.
- The overall confidence in the Oral Chronic Reference Dose is low to medium.
- The Inhalation Chronic Reference Concentration is 2.00E-05 (mg/m3).
- The Inhalation Chronic Reference Concentration has a modifying factor of 1.
- The Inhalation Chronic Reference Concentration has an uncertainty factor of 10.
- The Inhalation Chronic Reference Concentration is based on the Eisenbud et al. study from 1949.
- The Inhalation Chronic Reference Concentration study critical effects are sensitization and progression to CBD.
- The overall confidence in the Inhalation Chronic Reference Concentration is medium.
- The Dermal Chronic Reference Dose is 2.00E-05 (mg/kg-day).
- The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.0100.
Carcinogenic Health Effects
- The Oral Slope Factor is 4.30E+00 (mg/kg-day)-1.
- The Inhalation Unit Risk is 2.4E+00 (mg/m3)-1.
- The Inhalation Unit Risk study target organ is lung.
- The Inhalation Unit Risk study cancer type is tumors.
- The Inhalation Unit Risk is based on the Wagoner et al. study from 1980.
- The Dermal Slope Factor is 4.30E+02 (mg/kg-day)-1.
- The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.0100.