Toxicological Review of Barium and Compounds

Systolic blood pressures and body weights were measured at 1, 2, 4, 8, 12, and 16 

months, and organs (heart, liver, kidney, and aorta) were collected, weighed, and assayed for 

barium at 1, 4, and 16 months.  No change in mean systolic blood pressure was seen in groups 

exposed to 1 ppm barium in the drinking water.  However, after groups were exposed for 8 

months to 10 ppm, mean systolic blood pressure increased by 6 mm Hg (p<0.01) and continued 

to be significantly elevated through 16 months  (+4 mm Hg, p<0.01).  Significant increases 

(p<0.01) in mean systolic blood pressure were evident at 100 ppm starting at 1 month (+12 mm 

Hg) and continuing through 16 months (+16 mm Hg) of exposure.  An additional 12 rats exposed 

for 16 months to 100 ppm had reduced ATP and phosphocreatinine content of the myocardium, 

depressed rates of cardiac contraction, and depressed electrical excitability of the heart as 

compared with an additional control group of 18 rats.  No mortality was reported.  Growth rates 

were unaffected by barium, as were tissue weights.   Both 10 and 100 ppm barium resulted in 

significant increases in tissue barium.  This study identifies a NOAEL of 1 ppm (0.17 mg Ba/kg-

day) and a LOAEL of 10 ppm (0.82 mg Ba/kg-day) for hypertension in rats maintained on low-

mineral-content diets. 

4.2.1.8.  Schroeder and Mitchener (1975a, b) 

Schroeder and Mitchener (1975a) exposed Long-Evans rats (52/sex/group) to 0 or 5 ppm 

barium (as barium acetate) in drinking water from weaning to their natural death.  Dosages from 

drinking water were estimated to be 0.61 mg Ba/kg-day for males and 0.67 mg Ba/kg-day for 

females, using reference body weights and water intakes from U.S. EPA (1988).  The diet was 

characterized as a “low metal” diet, and it included 60% rye flour, 30% dried skim milk, 9% 

corn oil, 1% iodized table salt, and assorted vitamins; the barium content was not reported. 

Barium administration had no significant effect on the growth of males but increased the growth 

of older females.  The lifespan of the rats was not significantly affected.  The incidence of 

proteinuria in males exposed to barium for approximately 152 days (at 173 days of age) was 

significantly higher (p<0.05) than in controls; proteinuria was assessed by a dipstick method. 

Female rats at 532 and 773 days of age had higher (p<0.001) serum cholesterol concentrations 

than did controls tested at 516 and 769 days of age.  Serum glucose levels for males at these ages 

were also different from controls but did not follow an age-related pattern.  The authors attached 

no biological or toxicological significance to these serum chemistry results.  Histopathology of 

heart, lung, kidney, liver, and spleen did not reveal alterations.  No significant increases in the 

gross number of tumors were observed in the barium-exposed male (8/30) or female (15/33) rats 

as compared with the controls (4/26 and 17/24, respectively).  This study identifies a LOAEL of 

0.61 mg Ba/kg-day for renal glomerular damage evidenced as proteinuria in male rats 

maintained on low-mineral diets. 

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Schroeder and Mitchener (1975b) exposed white mice of the Charles River CD strain 

(36-54/sex) to 0 or 5 ppm barium (as barium acetate) in drinking water for their lifetimes.  Doses 

from drinking water were 1.18 mg Ba/kg-day for males and 1.20 mg Ba/kg-day for females (U.S. 

EPA, 1988).  The diet was characterized as a “low-metal” diet, and it included 60% rye flour, 

30% dried skim milk, 9% corn oil, 1% iodized table salt, and assorted vitamins; the barium 

content of the diet was not reported.  Growth and body weights were not affected by the barium 

treatment.  Histology of the heart, lung, liver, kidney, and spleen was normal.  In males, 

longevity (defined as the mean lifespan of the last surviving five animals of each sex in each 

treatment group) was significantly reduced (p

#

0.025); longevity of the barium-treated males was 

815 days compared with 920 days for the controls.  The mean lifespan, however, was not 

affected.  The incidences of lymphoma plus leukemia, and lung tumors in the male (7/37 and 

4/37, respectively) and female (5/21 and 3/21, respectively) mice exposed to barium were not 

significantly different from the incidences in the control mice (3/38 and 3/47 for lymphoma and 

leukemia in males and females, respectively, and 5/38 and 9/47 for lung tumors). 

4.2.2.  Inhalation Exposure 

Data on the toxicity of barium compounds in animals following inhalation exposure are 

limited to a subchronic study conducted by Tarasenko et al. (1977).  In this study, male albino 

rats (strain and number of animals per group were not reported) were exposed to 0, 1.15, or 5.2 

mg/m

3

 barium carbonate (0, 0.8, or 3.6 mg Ba/m

3

) for 4 hours/day, 6 days/week for 4 months. 

No information on aerosol generation or the size distribution of the particles was reported.  In the 

introduction section of the paper, the authors stated, “We have demonstrated by electron 

microscopy that the size of almost 80% of the dust particles is less than 2 

:

m”; however, it is not 

known if this statement refers to the aerosols generated for this study.  The following endpoints 

were used to assess toxicity:  body weight gain, arterial pressure, hematology (hemoglobin, 

leukocytes, and thrombocytes) and serum chemistry (glucose, phosphorus, total protein, alkaline 

phosphatase, and cholinesterase) parameters, urine calcium levels, bromosulfophthalein test of 

liver function, EKG measurement, and histologic examination (tissues examined were not 

listed). 

The authors noted that no alterations were observed in the rats exposed to 1.15 mg/m

3 

barium carbonate.  In the 5.2 mg/m

3

 group, a number of alterations were reported; however, it 

does not appear that the data were statistically analyzed.  The alterations included a 21% 

decrease in body weight gain, a 32% increase in arterial pressure, altered hematology parameters 

(decreases in hemoglobin and thrombocyte levels and increases in leukocyte levels), altered 

serum chemistry parameters (decreased sugar and total protein levels, increased phosphorus 

levels, decreased alkaline phosphatase activity, and increased cholinesterase activity), increased 

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