TABLE 3-1 Physical and Chemical Properties of Ba and Ba Compounds

Compound

Form

Molecular Weight

Solubility

Comment

Ba

Ba

137.3

Insoluble in water; soluble in alcohol

Ba chloride

BaCl2

208.2

375 g/L at 26°C

65.95% Ba

Ba chloride dehydrate

BaCl2·2H2O

244.3

375 g/L at 26°C

56.2% Ba

Ba acetate

Ba(CH3COO)2

255.5

1 g/1.5 mL

53.77% Ba

Ba sulfate

BaSO4

233.4

1.6 mg/L at 20°C

Also known as “barite”; 58.84% Ba

Ba carbonate

BaCO3

197.37

20 mg/L at 20°C

69.58% Ba

Ba sulfide

BaS

169.42

1.1 mg/L

81.08% Ba

Ba nitrate

Ba(NO3)2

261.38

Freely soluble

52.55% Ba

Source: Data from Merck 1989.

McCabe et al. (1970) and Calabrese (1977) reported that Ba was present in about 2,600 analyzed drinking water samples. It was found at about 1.5 milligrams (mg) per L in samples from areas of northern Illinois and northern Iowa. Because the solubility of Ba depends on the concentrations of total sulfate in the medium and because sufficient concentrations of sulfates are in the natural waters, it is difficult to maintain more than 1.5 mg/L in water (EPA 1985). The World Health Organization (WHO) has reported that the range of daily dietary intake of Ba is 300-1,770 g per day (4-25 µg per kilogram body weight per day). WHO (1990) also reported that the concentrations of Ba measured in U.S. drinking waters are 1-20 g/L. Several other reports indicated that the concentrations are much higher (Kopp 1969; Calabrese 1977).

Ba compounds are used to make not only drilling lubricants but also paints and pigments, textile dyes, greases, bricks, tile, glass, and rubber. Ba nitrate (Ba(NO3)2) is used in pyrotechnics. Because of its high radiopacity, BaSO4 has been used by doctors for taking x-rays of the stomach, intestines, and respiratory and urinary tract systems and in bronchography. A high-density suspension of Ba sulfate—usually 340 g suspended in 150 mL of water—is administered orally for radiologic evaluation of the small bowel. This represents a dose of 4.89 g per kilogram (kg).



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