table (alkaline-earth elements) and is chemically similar to aluminum with a high charge-to-nucleus ratio that leads to amphoteric behavior and a strong tendency to hydrolyze (EPA 1998b; ATSDR 2002). It has many unique chemical properties, being less dense than aluminum and stronger than steel (EPA 1998b). Because of its small atomic size, its most stable compounds are formed with small anions, such as fluoride and oxide. Beryllium is also capable of forming strong covalent bonds and may form organometallics, such as (CH3)2Be (EPA 1998b).

Beryllium has been estimated to be present in the earth’s crust at 2-5 mg/kg, and soil concentrations in the United States were reported to average 0.63 mg/kg and range from less than 1 to 15 mg/kg (ATSDR 2002). In its review of beryllium, ATSDR (2002) reported that surveys have detected beryllium in less than 10% of samples of U.S. surface water and springs, but detection limits are not reported in the review. The low water concentrations probably reflect beryllium’s typically entering water as beryllium oxide, which slowly hydrolyzes to the insoluble compound beryllium hydroxide (EPA 1998b).

Beryllium concentrations in U.S. air have typically been less than the detection limit of 0.03 ng/m3 (ATSDR 2002). Natural sources of airborne beryllium are windblown dust and volcanic particles, estimated to contribute 5 and 0.2 metric tons per year, respectively, to the atmosphere (Table 2-1). The principal anthropogenic contribution from airborne emissions is coal combustion. World coals have been reported to have a wide range of beryllium concentrations, from 0.1 to 1,000 mg/kg (Fishbein 1981), and the range in U.S. coal is 1.8-2.2 mg/kg (ATSDR 2002). On the basis of coal combustion of 640 million metric tons per year and a beryllium emission factor of 0.28 g/ton, EPA (1998b) has estimated that as much as 180 metric tons of beryllium may be emitted each year from U.S. coal combustion; fuel oil is burned at the rate of 148 million metric tons per year and has a beryllium emission factor of 0.048 g/ton, which would mean another 7.1 metric tons of beryllium released each year. Those estimates appear to conflict with emission estimates from the Toxic Release Inventory (TRI), which suggest a total of 3.5 tons per year released by electric utilities (Table 2-1); however, the TRI data are noted to be limited to particular types of facilities and to constitute an incomplete list (ATSDR 2002). The U.S. Department of Energy (DOE 1996) reported that beryllium in stack emissions of coal-fired power plants were 2-3 orders of magnitude greater than ambient air concentrations.

As of 1991, Rossman et al. (1991) reported that 45 beryllium-containing minerals had been identified, including silicates, aluminum silicates, and aluminum oxides. Four of them were commercially important: beryl, phenakite, bertrandite, and chrysoberyl. Unlike such metals as lead and

TABLE 2-1 Anthropogenic and Natural Emissions of Beryllium and Beryllium Compounds to the Atmospherea

Emission Source

Emission (tons/year)b

Natural

 

Windblown dust

5

Volcanic particles

0.2

Anthropogenicc,d

 

Industry

0.6

Metal mining

0.2

Electric utilities

3.5

Waste and solvent recovery (RCRA)

0.007

Total

9.507

aAdapted from Drury et al. 1978; EPA 1987; TRI99 2002.

bUnits are metric tons.

cData in Toxic Release Inventory (TRI) are maximum amounts released by each industry.

dThe sum of fugitive and stack releases is included in releases to air by a given industry.

ABBREVIATION: RCRA = Resource Conservation and Recovery Act.

SOURCE: ATSDR 2002.



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