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The Elements in the Second Rank

2 Beryllium

2.1 Identity

Table 2.1
CAS No., EINECS No. and molecular weight for beryllium

2.2 Physico-chemical properties

Beryllium is a group 2 element (IIA) in the periodic table, and the metal has the valence +2 (Be(II)) [12]. Metallic beryllium has low density and is a light-alloy metal. It is not soluble in cold water, but has low solubility in warm water. It is soluble in weak acids and bases [10].

Common compounds of the beryllium ion are beryllium hydroxide, beryllium chloride and beryllium sulfate. The solubility of the salts in water at neutral pH is relatively low, and is highest for beryllium chloride. Beryllium can also bind covalently and in the environment it forms organometallic compounds as e.g. (CH₃)₂Be [7]. The table below shows selected physico-chemical data for metallic beryllium.

Table 2.2
Physico-chemical data for metallic beryllium. Data from [1, 2]

2.3 Uses and consumption

2.3.1 Uses

Beryllium is used in the metal and electronics industry (televisions, calculator and computers) [18] and in the oil and gas industry [6, 17]. In Sweden, the aviation industry uses it in beryllium-copper alloys [6]. In Denmark, the most important use of beryllium is assumed to be the oil and gas industry where it is used in beryllium-copper alloys (pipelines and other submerged applications).

Additional fields of beryllium use are dental alloys [18, 20], sports equipment (golf ball and bike frames), air bags [21], X-ray equipment [22], additive to rocket fuel [22], ceramic/composite material [19, 20], and nuclear equipment [20].

2.3.2 Consumption

The global production of beryllium has in recent years been approximately 300-350 tons/year. USA consumed 240 tons of beryllium in 1997 [17].

The Danish consumption is assumed to be about 5 tons per year (it is assumed that the per capita consumption in Denmark and USA are identical).

2.4 Emissions to and occurrence in the environment

A significant emission of beryllium in Denmark comes from the use and disposal of metal and electronic equipment. Coal contains typically 0.5-3 mg Be/kg and oil about 0.002 mg/kg [6]. Therefore, incineration of fossil fuels results in production of waste products with beryllium and/or emission of beryllium to the atmosphere.

The concentration of beryllium in the aquatic environment is 0.0056-1 µg/L, see Table 2.3. The background concentration in the aquatic environment is 0.3 µg/L in fresh water [14]. In soil, concentrations between 0.01 and 40 mg/kg are reported. Beryllium is also found in waste water in concentration of less than 2 µg/L. In waste water treatment plants the highest concentrations are typically in the floating material in the primary clarifier. An increase in beryllium concentration in sludge in plants with sludge treatment can not be observed [9]. The results of sludge analysis are given in Table 2.4 (analysis performed in this study) corresponds to results from a previous study [9].

The fraction of beryllium used in consumer products will follow the waste streams and it is assumed that both combustion and disposal of solid waste can result in emission of beryllium to the environment. The concentrations of beryllium are according to Table 2.4 very low in waste gas from MSW incinerators and in leachate from landfill with MSW gas cleaning residuals.

From incineration of fossil fuels beryllium is emitted primarily as BeO. In Table 2.3 the typical background concentrations of beryllium in different environments are shown.

Table 2.3
Typical background concentration of beryllium in the environment. Data from [6, 14]

A limited investigation of the levels of beryllium (and the other elements covered by this study) in the major emissions and waste streams in society was conducted in the autumn of 2001, see Table 2.4. The level of beryllium in the waste streams is low in all waste types. The concentration of beryllium in road runoff retention basins was similar to the concentration of e.g. bismuth and palladium.

Table 2.4
Levels of beryllium in selected emissions and waste products from measurements conducted as part of this study in the autumn of 2001.

2.5 Danger classification

Beryllium has been recognised as problematic in the working environment since the 1970'ies. Beryllium and beryllium compounds are, except beryllium aluminum silicates, on the Danish list of dangerous compounds as very toxic when inhaled, toxic with risk of serious damage to health by prolonged exposure through inhalation, carcinogenic in category Carc2, irritant and sensitizing (R43) [4, 11]. Beryllium compounds except beryllium aluminum silicates are furthermore classified as dangerous for environment with risk phrase R51/53 (toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment).

Table 2.5
Classification of and risk phrases for beryllium and beryllium compounds

2.6 Toxicology

The toxicological effects of beryllium are due to the mode of action of the divalent beryllium ion, which can substitute Mg²⁺ in enzymes and thereby inactivate them.

Based of data on toxicity to animals and limited data on its human toxicology, inhaled beryllium is regarded as a possible carcinogen (group B2) by US EPA. Cancer can develop from exposure to high doses or chronic exposure of the lungs. Also oral intake is toxic [15].

According to IARC, there is sufficient evidence to classify beryllium and beryllium compounds as carcinogenic in humans and animals (Group 1) [3].

2.7 Environmental properties

2.7.1 Environmental chemistry

The salts of beryllium are in most cases the only beryllium compounds which will result in adverse effects on the environment. In the aquatic environment beryllium is found as beryllium ions (Be²⁺) or hydroxides. In aquatic ecosystems the concentration of beryllium ions is low since the salts have relatively low solubility at the pH, which in found in these environments. In fresh water beryllium is found as Be²⁺ and BeOH⁺, while the hydroxides are dominant in sea water [6]. The solubility of beryllium salts and thereby the concentration of beryllium ions in the water phase increases with decreasing pH [7].

Uptake of beryllium ions instead other metal ions can be observed. Metal ions are used in the metabolic functions of cells, and beryllium can substitute Mg²⁺ in enzymes and thereby deactivate enzymatically catalysed reactions.

Beryllium oxide (BeO) originating from combustion of fossil fuels is deposited by dry and wet deposition. In this form it is relatively immobile at pH values from 4 to 8 [7]. Only a limited amount of beryllium is therefore released by leaching from the soil environment.

2.7.2 Environmental toxicology

The acute toxicity of beryllium salts on Daphnia magna in the aquatic environment varies with a factor 10⁴ depending on which salt is used in the toxicological test. As seen in Table 2.6, the EC₅₀ is 0.050 mg/L for BeCl₂, whereas it is between 236 and 538 mg/L for Be(OH)₂ depending on water hardness. This large difference in toxicity is due mainly to the different solubility of the compounds.

Table 2.6
Selected test results for environmental toxicity of beryllium. Data from AQUIRE [5]

2.7.3 Bioaccumulation

The bioaccumulation of beryllium is low at all levels of the food web. However, bioconcentration in the aquatic environment has been observed on one occasion [6, 8]. It was the case in areas with intensive combustion of coal, which resulted in high concentrations of beryllium in the aquatic environments and aquatic organisms. Natural organometallic compounds with beryllium are not known.

2.8 Conclusions

Beryllium is used primarily in electronic equipment. The salts of beryllium are in most cases the only beryllium compounds, which can result in adverse environmental effects. In aquatic ecosystems the concentration of beryllium ions is low because the low solubility of the beryllium salts at the pH found in these environments. Beryllium has chronic effects (carcinogenic) on humans and animals. Beryllium compounds with high solubility exhibit adverse effects on aquatic standard test organisms at concentrations below 1 mg/L.

2.9 References

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