Toxicological profile for barium and barium compounds

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BARIUM AND BARIUM COMPOUNDS 

3.  HEALTH EFFECTS 

There are limited data on the potential of barium to impair reproductive function.  No significant 

alterations in pregnancy rate or gestation length were observed in rats or mice exposed to approximately 

200 mg barium/kg/day as barium chloride in drinking water (Dietz et al. 1992); the males were exposed 

for 60 days prior to mating and the females were exposed for 30 days. 

The highest NOAEL values and all reliable LOAEL values for reproductive effects in each species and 

duration category are recorded in Table 3-1 and plotted in Figure 3-1. 

3.2.2.6  Developmental Effects 

Studies regarding developmental effects of barium following oral exposure are limited to one human 

study (Morton et al. 1976) and three animal studies (Dietz et al. 1992; Tarasenko et al. 1977).  A 

statistically significant negative correlation was found between barium concentrations in drinking water 

and human congenital malformation rates of the central nervous system in South Wales (Morton et al. 

1976).  A negative correlation implies that as the barium concentration in drinking water increased, the 

rate of central nervous system malformations decreased.  This statistical study is of limited value in 

identifying a NOAEL for developmental effects because exposure conditions (duration and frequency of 

exposure, dose, number of subjects exposed) were not characterized. 

Developmental effects were reported in a study in which an unspecified animal species was orally 

administered a dose of barium carbonate that was equal to 1/16 of the LD

50

 for 24 days prior to 

conception and pregnancy (Tarasenko et al. 1977).  Reported effects in offspring included increased 

mortality during the first 2 months, increased leukocyte count, disturbances in liver function, and 

increased urinary excretion of hippuric acid.  This study is inadequate for evaluating developmental 

effects of oral barium exposure because of major study limitations.  These limitations include a general 

lack of information provided by the authors regarding experimental methods, exposure conditions, and 

test results, and no information as to the species and number of animals tested, the purity of the test 

material, the statistical methods used, and whether or not controls were used.   

In studies by Dietz et al. (1992), male rats and mice were exposed to barium chloride in drinking water 

for 60 days and mated to females exposed to barium chloride for 30 days.  In the rats, exposure to 

180/200 mg barium/kg/day resulted in significant decreases in pup birth weights.  Decreases in the live 

litter size at postnatal days 0 and 5 were also observed in the 180/200 mg barium/kg/day group, but the 

difference was not statistically significant; litter sizes were 9.0 and 9.3 pups in controls on days 0 and 5, 

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BARIUM AND BARIUM COMPOUNDS 

3.  HEALTH EFFECTS 

and 7.2 and 7.1 pups on days 0 and 5 in the 200 mg barium/kg/day group.  No adverse developmental 

effects were observed in the mice (highest dose tested was 200 mg barium/kg/day). 

The highest NOAEL values and all reliable LOAEL values for developmental effects in each species and 

duration category are recorded in Table 3-1 and plotted in Figure 3-1. 

3.2.2.7  Cancer 

No studies were located regarding cancer in humans after oral exposure to barium.  Several animal studies 

evaluated the induction of tumors following chronic oral exposure to barium (NTP 1994; Schroeder and 

Mitchener 1975a, 1975b).  In studies by Schroeder and Mitchener (1975a, 1975b), rats and mice were 

exposed to 0.7 and 0.95 mg barium/kg/day, respectively, as barium acetate in drinking water for lifetime.  

No differences in the incidence of tumors were noted between treated animals and vehicle controls in 

either study.  These studies are inadequate for evaluating the carcinogenic potential of barium because 

insufficient numbers of animals were used for a carcinogenicity study, it was not determined whether or 

not a maximum tolerated dose was achieved, a complete histological examination was not performed, the 

purity of the test material was not specified, and only one exposure dose was used in each study.  Studies 

conducted by the NTP (1994) are considered adequate for carcinogenicity assessment.  In rats exposed to 

doses as high as 60–75 mg barium/kg/day as barium chloride in drinking water, significant negative 

trends for mononuclear cell leukemia, adrenal medulla pheochromocytoma, and mammary gland 

neoplasms were found.  No significant increases in malignant tumors were observed.  Similarly, no 

increases in malignant tumor incidences were observed in mice chronically exposed to doses up to 160– 

200 mg barium/kg/day as barium chloride in drinking water. 

3.2.3 

Dermal Exposure  

Limited information is available regarding the health effects of barium following dermal exposure.  

Barium salts would be expected to have a local effect on skin surfaces and would not likely be absorbed 

systematically to any great extent.  Available studies include a case report of an individual exposed 

dermally to molten barium chloride (Stewart and Hummel 1984), a skin irritation study evaluating barium 

carbonate in experimental animals (Tarasenko et al. 1977), and a skin-painting study in which mice were 

exposed dermally to a barium hydroxide extract of tobacco leaf (Van Duuren et al. 1968).  No reliable 

information was available from any of these dermal studies to identify study NOAELs or LOAELs for 

barium.  In the case report (Stewart and Hummel 1984), the dermal burns that developed in the individual 

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