Toxicological profile for barium and barium compounds

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BARIUM AND BARIUM COMPOUNDS 

3.  HEALTH EFFECTS 

chemicals do not pose a significant health risk, particularly in view of the fact that hormone mimics exist 

in the natural environment.  Examples of natural hormone mimics are the isoflavinoid phytoestrogens 

(Adlercreutz 1995; Livingston 1978; Mayr et al. 1992).  These chemicals are derived from plants and are 

similar in structure and action to endogenous estrogen.  Although the public health significance and 

descriptive terminology of substances capable of affecting the endocrine system remains controversial, 

scientists agree that these chemicals may affect the synthesis, secretion, transport, binding, action, or 

elimination of natural hormones in the body responsible for maintaining homeostasis, reproduction, 

development, and/or behavior (EPA 1997).  Stated differently, such compounds may cause toxicities that 

are mediated through the neuroendocrine axis.  As a result, these chemicals may play a role in altering, 

for example, metabolic, sexual, immune, and neurobehavioral function.  Such chemicals are also thought 

to be involved in inducing breast, testicular, and prostate cancers, as well as endometriosis (Berger 1994; 

Giwercman et al. 1993; Hoel et al. 1992). 

No studies were located regarding endocrine disruption in human and/or animals after exposure to 

barium; additionally, in vitro studies were not located. 

3.7 

CHILDREN’S SUSCEPTIBILITY  

This section discusses potential health effects from exposures during the period from conception to 

maturity at 18 years of age in humans, when all biological systems will have fully developed.  Potential 

effects on offspring resulting from exposures of parental germ cells are considered, as well as any indirect 

effects on the fetus and neonate resulting from maternal exposure during gestation and lactation.  

Relevant animal and in vitro models are also discussed. 

Children are not small adults.  They differ from adults in their exposures and may differ in their 

susceptibility to hazardous chemicals.  Children’s unique physiology and behavior can influence the 

extent of their exposure.  Exposures of children are discussed in Section 6.6, Exposures of Children. 

Children sometimes differ from adults in their susceptibility to hazardous chemicals, but whether there is 

a difference depends on the chemical (Guzelian et al. 1992; NRC 1993).  Children may be more or less 

susceptible than adults to health effects, and the relationship may change with developmental age 

(Guzelian et al. 1992; NRC 1993).  Vulnerability often depends on developmental stage.  There are 

critical periods of structural and functional development during both prenatal and postnatal life, and a 

particular structure or function will be most sensitive to disruption during its critical period(s).  Damage 

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BARIUM AND BARIUM COMPOUNDS 

3.  HEALTH EFFECTS 

may not be evident until a later stage of development.  There are often differences in pharmacokinetics 

and metabolism between children and adults.  For example, absorption may be different in neonates 

because of the immaturity of their gastrointestinal tract and their larger skin surface area in proportion to 

body weight (Morselli et al. 1980; NRC 1993); the gastrointestinal absorption of lead is greatest in infants 

and young children (Ziegler et al. 1978).  Distribution of xenobiotics may be different; for example, 

infants have a larger proportion of their bodies as extracellular water, and their brains and livers are 

proportionately larger (Altman and Dittmer 1974; Fomon 1966; Fomon et al. 1982; Owen and Brozek 

1966; Widdowson and Dickerson 1964).  The infant also has an immature blood-brain barrier (Adinolfi 

1985; Johanson 1980) and probably an immature blood-testis barrier (Setchell and Waites 1975).  Many 

xenobiotic metabolizing enzymes have distinctive developmental patterns.  At various stages of growth 

and development, levels of particular enzymes may be higher or lower than those of adults, and 

sometimes unique enzymes may exist at particular developmental stages (Komori et al. 1990; Leeder and 

Kearns 1997; NRC 1993; Vieira et al. 1996).  Whether differences in xenobiotic metabolism make the 

child more or less susceptible also depends on whether the relevant enzymes are involved in activation of 

the parent compound to its toxic form or in detoxification.  There may also be differences in excretion, 

particularly in newborns who all have a low glomerular filtration rate and have not developed efficient 

tubular secretion and resorption capacities (Altman and Dittmer 1974; NRC 1993; West et al. 1948).  

Children and adults may differ in their capacity to repair damage from chemical insults.  Children also 

have a longer remaining lifetime in which to express damage from chemicals; this potential is particularly 

relevant to cancer. 

Certain characteristics of the developing human may increase exposure or susceptibility, whereas others 

may decrease susceptibility to the same chemical.  For example, although infants breathe more air per 

kilogram of body weight than adults breathe, this difference might be somewhat counterbalanced by their 

alveoli being less developed, which results in a disproportionately smaller surface area for alveolar 

absorption (NRC 1993). 

There is limited information on age-related differences in the toxicity of barium in humans or animals.  

Deng et al. (1991) and Lewi and Bar-Khayim (1964) reported cases from two food poisoning incidents 

that involved exposure of adults and children.  Both reports noted that children did not seem to be 

affected by the barium carbonate exposure; however, these data should be interpreted cautiously because 

neither involved examination of exposed children and no information is available on barium carbonate 

intake.  There are limited data on the developmental toxicity of barium in laboratory animals.  The body 

weights of the offspring of rats exposed to barium chloride prior to mating were significantly lower than 

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