TOXICOLOGICAL PROFILE FOR BARIUM AND COMPOUNDS ...

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2. HEALTH EFFECTS
of barium, well-conducted epidemiological studies evaluating these health
effects would be useful.
Biomarkers of Exposure and Effect. There are no established biomarkers
of exposure for barium. Analytical methods exist for measuring barium in
blood, urine, feces, and biological tissues (Mauras and Allain 1979; Schramel
1988; Shiraishi et al. 1987); however, there are no data correlating levels of
barium in these tissues and fluids with exposure.
Symptoms of barium toxicity, such as hypokalemia (Diengott et al. 1964;
Gould et al. 1973; Lewi and Bar-Khayim 1964; Phelan et al. 1984; Shankle and
Keane 1988; Stewart and Hummel 1984; Talwar and Sharma 1979; Wetherill et al.
1981) hypertension (Das and Singh 1970; Diengott et al. 1964; Gould et al.
1973; Wetherill et al. 1981), and heart (Lewi and Bar-Khayim 1964; McNally
1925; Talwar and Sharma 1979), muscle (Das and Singh 1970; Diengott et al.
1964; Gould et al. 1973; Lewi and Bar-Khayim 1964; McNally 1925; Morton 1945;
Ogen et al. 1967; Phelan et al. 1984; Wetherill et al. 1981), and nerve
effects (Das and Singh 1970; Diengott et al. 1964; Gould et al. 1973; Lewi and
Bar-Khayim 1964; Morton 1945; Ogen et al. 1967; Phelan et al. 1984; Wetherill
et al. 1981), are well documented. However, there are no quantitative studies
correlating these effects with dose. For purposes of facilitating medical
surveillance, studies to determine useful biomarkers of exposure and effect
for barium would be useful.
Absorption, Distribution, Metabolism, and Excretion. The database on
absorption, distribution, metabolism, and excretion of barium is limited.
Existing studies indicate that barium is absorbed more efficiently from the
respiratory tract (Cuddihy and Ozog 1973b) than from the digestive system
(ICRP 1973; Tipton et al. 1969), primarily deposited in the bones and teeth
(Bauer et al. 1957; Cuddihy and Griffith 1972; Losee et al. 1974; Miller et
al. 1985; Moloukhia and Ahmed 1979; Sowden 1958; Sowden and Pirie 1958; Sowden
and Stitch 1957), and excreted mostly in feces and urine (Cuddihy and Griffith
1972; Tipton et al. 1966). Deposition in bones and teeth and excretion in
feces and urine appear to be independent of the route of exposure.
Essentially no data exist on dermal absorption, distribution, or excretion;
however, this route is not considered to be a significant source of exposure
to barium. Because barium is an element, it is not metabolized. No
significant data exist on the metabolism of barium compounds in the body.
Additional studies evaluating the binding and/or complexing of barium and
barium compounds with biological macromolecules or organic molecules in the
body would be useful. Studies quantifying the extent of absorption following
inhalation, oral, and dermal exposure also would be useful because of limited
absorption data.
Comparative Toxicokinetics. Based on available data, there do not
appear to be significant differences in the toxicokinetics of barium between
species (Chou and Chin 1943; Cuddihy and Griffith 1972; McCauley and