Beryllium

(endorsed 2011)

Guideline

Based on health considerations the concentration of beryllium in drinking water should not exceed 0.06 mg/L.

General description

Beryllium can enter source water through the weathering of rocks, atmospheric deposition, and discharges. The primary source of beryllium in the environment is the burning of fossil fuels. Other less significant sources are slag and ash dumps.

Beryllium is used in a number of specialised applications including ceramic formulations, electrical and electronic components, and X-ray tubes. It is also used to stiffen the mantles of gas acetylene lamps.

Beryllium concentrations in drinking water overseas are generally very low, usually less than 0.001 mg/L. For example, the concentration of beryllium in drinking water was based on a survey of 1577 drinking-water samples throughout the United States, where beryllium was detected in 5.4% of samples with mean and maximum concentrations of 0.00019 and 0.00122 mg/L (0.19 and 1.22 µg/L), respectively. In Australian river waters the levels are reported to be < 0.00001 to 0.00012 mg/L (10–30 ng/L average) (WHO 2001).

If it is assumed the maximum concentration in drinking water in Australia is 0.0012 mg/L then 2 L/day will give a daily intake of 0.0024 mg beryllium. The World Health Organization (WHO 2001) reports an intake of 0.00012 mg/day from food as the mid point from an Australian survey. Thus the total intake of beryllium may be about 0.0025 mg/day. The proportion from water may approximately be as much as 95%.

Atmospheric exposure to beryllium is generally much less than from food or water, but constitutes a greater hazard. Cigarette smokers can be exposed to higher concentrations than nonsmokers.

Typical values in Australian drinking water

Australian drinking water supplies have not been routinely monitored for beryllium.

Treatment of drinking water

There are no published methods for the removal of beryllium from drinking water supplies.

Measurement

The concentration of beryllium in drinking water can be determined by graphite furnace atomic absorption spectroscopy or inductively coupled plasma emission spectroscopy (APHA Method 3500-Be Parts B or C 1992). The limit of determination is approximately 0.002 mg/L.

Health considerations

Beryllium compounds are not readily absorbed by the gastrointestinal tract since they tend to be insoluble at pH values normally found in the gut. A significant proportion of the beryllium that is absorbed is incorporated into bone and has a biological half-life of more than one year.

The toxicology of beryllium has been reviewed by United States Environmental Protection Agency (USEPA 1998), the WHO (2001) and US Agency for Toxic Substances and Disease Registry (ATSDR 2002). Several chronic oral animal studies in dogs, rats and mice were reviewed. Dogs chronically exposed to soluble beryllium sulfate in the diet developed gastrointestinal lesions and bone marrow hypoplasia. Rickets were observed in rats exposed to sparingly soluble beryllium carbonate in the diet for 2–24 weeks, possibly due to decreased gastrointestinal absorption of phosphorus subsequent to formation of insoluble beryllium phosphate in the intestine.

WHO (2001) described the derivation of a tolerable daily intake (TDI) of 0.002 mg per kg bodyweight (mg/kg bw) by application of an uncertainty factor of 300 to a benchmark dose (BMD) of 0.46 mg/kg bw/day. The BMD was calculated at the lower 95% confidence interval for a 10% incidence of small intestinal lesions, assumed to be equal to a no-observed-adverse-effect level (NOAEL), in dogs chronically exposed to dietary beryllium sulfate tetrahydrate. The uncertainty factor of 300 included a factor of 10 intraspecies variation, 10 for interspecies variation, and a 3-fold factor for database deficiencies (no studies available on developmental effects and no mechanistic/mode of action data to suggest this may not be an issue). Although there are several chronic oral animal studies, there is a lack of human toxicity data by the oral route, reproductive/developmental end-points have not been adequately assessed, and oral studies examining immunological end-points are lacking. Since the principal study in dogs is of chronic duration and a benchmark dose was used, there are no uncertainty factors for duration or NOAEL/LOAEL (lowest observed adverse effect level) extrapolation. This derivation of the TDI uses the same logic, $\text{BMD}_{10}$ and uncertainty factors as those described by the United States Environmental Protection Agency (USEPA 1998). The Agency for Toxic Substances and Disease Registry, using the same dog data but a different curving-fitting program to the USEPA (1998), determined a $\text{BMD}_{10}$ of 0.56 mg/kg bw/day, to which they applied an uncertainty factor of 300 (same rationale as WHO 2001) to obtain a minimum risk level of 0.002 mg/kg bw/day (ATSDR 2002).

There are no reliable data on the human health effects of oral exposure to beryllium. Inhalation is known to cause serious health effects, with long-term exposure resulting in pulmonary granulomatosis (a type of lung tumour). The inhalation data led the International Agency for Research on Cancer to conclude that beryllium and beryllium compounds are carcinogenic to humans (Group 1, sufficient evidence of carcinogenicity in humans and sufficient evidence in animals) (IARC 1993).

There is no clear evidence that the compounds are carcinogenic when administered orally. Beryllium was not mutagenic in tests with different strains of bacteria, but caused chromosomal aberrations and gene mutations in cultured mammalian cells.

Experiments with laboratory mice have shown that beryllium can cross the placenta and is foetotoxic (toxic to the foetus).

Derivation of guideline

Using the oral TDI of 0.002 mg/kg bw from WHO (2001), a drinking water guideline can be derived as follows:

$$\text{0.06 mg/L} = \frac{\text{0.002 mg/kg bw x 70 kg x 0.8}}{\text{2 L/day}}$$

Where:

• 0.002 mg/kg bw is the tolerable daily intake and includes a 300 fold safety factor to allow for intraspecies and interspecies variation.

• 70 kg is taken as the average weight of an adult.

• 0.8 is a proportionality factor based on the assumption that 80% of total daily intake is attributable to the consumption of drinking water.

• 2 L/day is the estimated maximum amount of water consumed by an adult.

References

APHA Method 3500-Be Part B, (1992). Beryllium: Atomic Absorption Spectrophotometric method. Standard Methods for the Examination of Water and Wastewater, 18th edition. American Public Health Association, Washington.

APHA Method 3500-Be Part C, (1992). Beryllium: Inductively Coupled Plasma method. Standard Methods for the Examination of Water and Wastewater, 18th edition. American Public Health Association, Washington.

ATSDR (Agency for Toxic Substances and Disease Registry) (2002). Toxicological Profile for Beryllium. ATSDR.

DoHA (2010) The Poisons Standard; Schedule 1-Standard for the Uniform Scheduling of Medicines and Poisons, Department of Health and Ageing, Commonwealth of Australia, Canberra.

IARC (International Agency for Research on Cancer) (1993). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Beryllium, Cadmium, Mercury, and Exposures in the Glass Manufacturing Industry. World Health Organization, IAARC 58, Lyons.

USEPA (United States Environmental Protection Agency) (1998). Toxicological review of beryllium and compounds (CAS No. 7440-41-7). USEPA, Washington, DC.

WHO (World Health Organization) (2001). Concise International Chemical Assessment Document 32: Beryllium and beryllium compounds. WHO, Geneva, Switzerland.