Who/sde/wsh/03. 04/76

BARIUM IN DRINKING-WATER 

 

 

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concentrations in municipal drinking-water derived from groundwater were reported 

to be between 700 and 1160 µg/litre (Lanciotti et al., 1992). In the Cambrian-Vendian 

aquifer in Estonia, which is low in sulfate, barium concentrations ranged from 0.07 to 

6.37 mg/litre, with a median value of 0.8 mg/litre. However, there was a significant 

variation in concentration over the aquifer; in one anomalous area, the median 

concentration was 2.41 mg/litre (A. Marandi, personal communication, 2003). 

 

If an average daily water consumption of 2 litres is assumed, intake from drinking-

water will range from about 2 to 1200 µg. The great majority of intakes will be below 

200 µg, and most will be below 100 µg.  

 

3.3 Food 

 

Most foods contain less than 0.002 mg of barium per g (Gormican, 1970). Some 

cereal products and nuts may contain high levels: e.g., bran flakes, 0.0039 mg/g; 

pecans, 0.0067 mg/g; and Brazil nuts, up to 4 mg/g (Mertz, 1986). 

 

The long-term mean dietary barium intake for adults has been found to be 0.75 

mg/day (range 0.44–1.8 mg/day), including food and fluids (ICRP, 1975); 0.6 mg/day 

from total diet (IPCS, 1990); and 1.24 mg/day (range 0.65–1.8 mg/day) for food only 

(Schroeder et al., 1972). 

 

Barium sulfate is the major barium compound used medicinally. Often called a 

barium “meal,” this very poorly soluble compound is employed as an opaque contrast 

medium for X-ray studies of the gastrointestinal tract.  

 

3.4 Estimated total exposure and relative contribution of drinking-water 

 

On the basis of the above considerations, the mean daily intake of barium from food, 

water and air is estimated to be slightly more than 1 mg/day, food being the primary 

source for the non-occupationally exposed population. However, where barium levels 

in water are high, drinking-water may contribute significantly to barium intake. 

 

4. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND 

HUMANS 

 

Soluble barium salts are most readily absorbed, although insoluble compounds may 

also be absorbed to a significant extent (McCauley & Washington, 1983; Clavel et al., 

1987). The degree of absorption of barium from the gastrointestinal tract also depends 

on the animal species, the contents of the gastrointestinal tract, diet and age (Taylor et 

al., 1962; McCauley & Washington, 1983; Clavel et al., 1987). Data on 

gastrointestinal absorption in humans are limited to a study conducted by Lisk et al. 

(1988); in this mass balance study of one man consuming a single dose of 179.2 mg 

of barium in 92 g of Brazil nuts, it was estimated that at least 91% of the dose was 

absorbed (List et al., 1988; US EPA, 1999). 

 

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BARIUM IN DRINKING-WATER 

 

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Barium is rapidly transported in blood plasma, principally to bone (US NRC, 1977). 

Approximately 91% of the total body burden of barium is in the bone (IPCS, 1990). 

Elevated barium/calcium ratios were found in the teeth of children exposed to 

drinking-water containing 10 mg of barium per litre (Miller et al., 1985). It has been 

reported that barium crosses the placental barrier in humans (Schroeder et al., 1972). 

 

The faecal route of excretion of barium is the most important in humans and animals 

(Ohanian & Lappenbusch, 1983); in humans, 20% of an ingested dose is excreted in 

the faeces and 7% in the urine within 24 h (US NRC, 1977; IPCS, 1990). 

 

5. EFFECTS ON LABORATORY ANIMALS AND IN VITRO TEST SYSTEMS 

 

5.1 Acute exposure 

 

Acute oral LD

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 values in rats for barium chloride, barium carbonate and barium 

sulfide range from 118 to 800 mg/kg of body weight (NIOSH, 1989; IPCS, 1990; 

ATSDR, 1992). 

 

5.2 Short-term exposure 

 

No effects on blood pressure were seen in Sprague-Dawley rats exposed to 100 mg of 

barium per litre as barium chloride in drinking-water (equivalent to 1.5 mg/kg of body 

weight per day) for up to 20 weeks (McCauley et al., 1985). In the same series of 

studies, no changes were seen in blood pressure in hypertension-susceptible Dahl and 

uninephrectomized rats exposed for 16 weeks to up to 1000 mg of barium per litre in 

distilled water or 0.9% saline. At 1000 mg/litre, however, ultrastructural changes in 

the glomeruli of the kidney were discernible by electron microscopy. In addition, no 

significant electrocardiographic changes during (-)-norepinephrine challenge were 

observed in Sprague-Dawley rats ingesting drinking-water containing 250 mg of 

barium per litre for 5 months (McCauley et al., 1985). 

 

Groups of 10 male and 10 female mice were administered barium chloride dihydrate 

in drinking-water for 13 weeks at concentrations of 0, 125, 500, 1000, 2000 or 4000 

mg/litre for 13 weeks, corresponding to average daily doses of 0, 15, 55, 100, 205 and 

450 mg of barium per kg of body weight in males and 0, 15, 60, 110, 200 and 495 mg 

of barium per kg of body weight in females. Complete histopathological examinations 

were performed on all mice in the control, 2000 mg/litre and 4000 mg/litre groups, 

and histopathological examinations of the kidneys were performed on the male mice 

in the 1000 mg/litre group. Cardiovascular studies and haematological and serum 

electrolyte analyses were not performed on the mice. A NOAEL of 2000 mg/litre was 

derived based on significant mortality at the 4000 mg/litre dose and on the incidence 

of chemical-related nephropathy. Although decreased absolute and relative liver 

weights were observed at the 1000, 2000 and 4000 mg/litre doses in females, no 

histopathological effects on the liver were observed at any dose level, and so the 

effect was deemed to be non-adverse (US NTP, 1994).  

 

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