Barium exposure

There is no routine medical test to determine whether you have been exposed to barium. Doctors can measure barium in body tissues and fluids, such as blood, bones, urine, and feces, using very complex instruments. This is normally done only for cases of severe barium poisoning and for medical research. More information on testing for barium exposure is found in Chapters 2 and 6. 

The Occupational Safety and Health Administration (OSHA) has a legally enforceable occupational exposure limit of 0.5 milligrams (mg) of soluble barium compounds per cubic meter (nr) of air averaged over an 8-hour work day. The OSHA 8-hour exposure limit for barium dust in air is 5-10 mg/m3. The National Institute for Occupational Safety and Health (NIOSH) has classified barium exposures of 250 mg/m3as immediately dangerous to life or health. 

The effect of oral barium exposure on various blood chemistry parameters that are important for cardiovascular function has been evaluated in only one experimental study with humans (Wones et al. 1990). In this study, 0.2 mg barium/kg/day as barium chloride was supplied in the drinking water of subjects for 4 weeks. No clinically significant changes were noted in any of the blood chemistry parameters monitored (total plasma cholesterol plasma triglycerides plasma HDL and LDL cholesterol plasma apolipoproteins and serum glucose, potassium, calcium, and albumin). 

Renal effects observed in animals following oral barium exposure have been minor. Increased kidney/body weight ratios have been noted in rats exposed acutely by gavage to 198 mg barium/kg/day as barium chloride however, this change was not associated with gross or microscopic renal lesions (Borzelleca et al. 1988). 

Developmental effects were reported in one study in which female rats were treated orally during conception and pregnancy with approximately 18.3 mg barium/kg/day as barium carbonate (Tarasenko et al. 1977). Reported effects in offspring included increased mortality, increased leukocyte count, disturbances in liver function, and increased urinary excretion of hippuric acid. The later 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 number of animals tested, the purity of the test material, the statistical methods used, and whether or not controls were used. No other animal studies evaluating developmental effects were available. 

No data on musculoskeletal involvement in cases of barium exposure by other than oral or inhalation modes have been reported for humans. In animals receiving acute doses of barium compounds parenterally, both muscle twitching and paralysis have been reported. Muscle twitching usually occurred within minutes of injection with flaccid paralysis following (Roza and Berman 1971 Schott and McArdle 1974). Parenteral administration is a very rare route of barium exposure, but once barium has entered the bloodstream and has been systemically distributed, it will have the same effects on the same organ. Similar symptoms are expected to occur in humans acutely exposed to barium via inhalation and oral routes. 

Hypokalemia and hypertension are effects usually found in cases of acute and intermediate exposures to relatively high doses of barium. While it is reasonable to expect the dose level to influence the presence of these effects, there are no data supporting a correlation between dose level and either appearance of or degree of hypokalemia and hypertension. Observation of hypokalemia and hypertension together is indicative of barium exposure, however, other toxicants and disease states can produce these effects. 

The cations potassium, calcium, and magnesium also interact with barium. Barium exposure, for example, may cause a buildup of potassium inside the cell resulting in extracellular hypokalemia which is believed to mediate barium- induced paralysis. In fact, potassium is a powerful antagonist of the cardiotoxic and paralyzing effects of barium in animals (Foster et al. 1977 Jaklinski et al. 

The limited data available suggest that certain subgroups of the population may be more susceptible to barium exposure than the general population. These include people with cardiovascular problems, those taking certain prescription drugs, children, pregnant women, smokers, and people with lung disease. 

A consistent toxic effect of barium in humans and animals is increased blood pressure. Therefore, humans with hypertension could be at increased risk from either chronic, intermediate, or acute barium exposure. In addition, the cardiotoxic effects of barium exposure could increase the risk for those individuals suffering from other heart problems. 

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