Toxicological profile for barium and barium compounds
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Death Respiratory Cardiovascular Gastrointestinal Hematological Musculoskeletal Hepatic Renal
Figure 3-1 Levels of Significant Exposure to Barium - Oral (Continued) Intermediate (15-364 days) Systemic BARIUM AND BARIUM COMPOUNDS mg/kg/day 1000
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Cancer Effect Level-Animals LOAEL, More Serious-Animals LOAEL, Less Serious-Animals NOAEL - Animals Cancer Effect Level-Humans LOAEL, More Serious-Humans LOAEL, Less Serious-Humans NOAEL - Humans LD50/LC50 for effects other than Cancer
Minimal Risk Level 45 22m 22m 18r
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Body Weight Metabolic Immuno/Lymphor Neurological Reproductive Developmental Figure 3-1 Levels of Significant Exposure to Barium - Oral
Intermediate (15-364 days) Systemic BARIUM AND BARIUM COMPOUNDS mg/kg/day 1000
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3. HEALTH EFFECTS c-Cat
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-Humans k-Monkey
m-Mouse h-Rabbit a-Sheep f-Ferret j-Pigeon e-Gerbil s-Hamster g-Guinea Pig n-Mink o-Other
Cancer Effect Level-Animals LOAEL, More Serious-Animals LOAEL, Less Serious-Animals NOAEL - Animals Cancer Effect Level-Humans LOAEL, More Serious-Humans LOAEL, Less Serious-Humans NOAEL - Humans LD50/LC50 Minimal Risk Level for effects other than Cancer 46
Death Respiratory Cardiovascular Gastrointestinal Hematological Musculoskeletal Hepatic Renal Ocular Body Weight Metabolic Immuno/Lymphor Neurological Reproductive Figure 3-1 Levels of Significant Exposure to Barium - Oral (Continued) Chronic (≥365 days) Systemic mg/kg/day 1000 45m
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BARIUM AND BARIUM COMPOUNDS 3. HEALTH EFFECTS 10 48r
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e-Gerbil s-Hamster g-Guinea Pig n-Mink
o-Other Cancer Effect Level-Animals LOAEL, More Serious-Animals LOAEL, Less Serious-Animals NOAEL - Animals Cancer Effect Level-Humans LOAEL, More Serious-Humans LOAEL, Less Serious-Humans NOAEL - Humans LD50/LC50 for effects other than Cancer Minimal Risk Level 47
48 BARIUM AND BARIUM COMPOUNDS 3. HEALTH EFFECTS alteration in blood pressure measurements or alterations in hypertension, heart disease, or stroke among residents of two communities with elevated (0.2 mg barium/kg/day) or low (0.003 mg barium/kg/day) levels of barium in drinking water (Brenniman and Levy 1985; Brenniman et al. 1979a, 1981). Interpretation of this study is limited by the lack of information on tap water consumption, and the fact that blood pressure was measured 3 times in a single 20-minute period and not repeatedly over a longer period, and the incidence of hypertension, stroke, and heart disease was taken from subject-completed questionnaires and not confirmed by testing or examination of medical records. Brenniman and associates (Brenniman and Levy 1985; Brenniman et al. 1979a, 1981) also conducted a mortality study of residents living in communities with elevated or low barium levels in drinking water. Significantly higher mortality rates for cardiovascular disease and heart disease (arteriosclerosis) were found in the elevated barium communities (0.06–0.3 mg barium/kg/day) than in the low barium communities (0.006 mg barium/kg/day). The largest difference between the groups was in individuals 65 years of age and older. These results should be interpreted cautiously because the study did not control for a number of potential confounding variables such as the use of water softeners, which would reduce the amount of barium and increase sodium levels, duration of exposure, or actual barium intakes. Several animal studies have examined potential cardiovascular end points following acute-, intermediate-, or chronic-duration exposures. No histological alterations have been observed in the hearts of rats and mice exposed to barium chloride, barium acetate, or an unspecified barium compound for intermediate or chronic durations (Borzelleca et al. 1988; McCauley et al. 1985; NTP 1994; Perry et al. 1983, 1985, 1989; Schroeder and Mitchener 1975a; Tardiff et al. 1980). Significant increases in systolic blood pressure were observed in rats exposed to 8.6 or 11 mg barium/kg/day for 1 or 4 months, respectively; no effect levels were 1.0 and 1.2 mg barium/kg/day (Perry et al. 1983, 1985, 1989). When the duration of exposure was longer (8–16 months), the LOAEL for increased blood pressure was 0.80 mg barium/kg/day and the NOAEL was 0.17 mg barium/kg/day (Perry et al. 1983, 1985, 1989). Depressed rates of cardiac contraction and cardiac conductivity and decreased cardiac ATP levels were observed in another group of rats exposed to 7.2 mg barium/kg/day. In contrast to the findings in the Perry study (1983, 1985, 1989), no significant alterations in blood pressure were observed in rats exposed to up to 150 mg barium/kg/day in drinking water for 16 weeks (McCauley et al. 1985); it should be noted that the McCauley et al. (1985) studies were conducted in uninephrectomized rats or Dahl salt-sensitive and salt-resistant rats. NTP (1994) also found no significant alterations in blood pressure, heart rate, or ECG readings in rats exposed to 180 mg barium/kg/day for 45 or 90 days. The low metal diet used in the Perry et al. (1983, 1985, 1989) study may have influenced the study outcome.
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