Barium [Ba, 56]
25
Median Ba concentration in bottled water of the EU countries is 30.6 μg/L, which
is about the same in tap water at 30.1 μg/L (Birke et al. 2010). In Poland, drinking
water contains Ba up to 60 μg/L. The guideline value of Ba concentration in drinking water is established at 700 μg/L by the WHO (2011a), whereas this value estimated by the European Commission is 1000 μg/L (EU 1998a).
4.4 AIR
The range of Ba concentrations in air of remote area (Antarctica) is 0.02–0.73 ng/m 3
(Table 4.1). Ba contents in air of rural and urban regions increase up to 90 ng/m 3 and
above 100 ng/m 3 , respectively. Its main sources are mainly oil and coal combustion
(ATSDR 2007a).
4.5 PLANTS
Barium is easily uptake by all plants, especially from acidic soils. Its mean contents
in the most plants range from 2 to 14 mg/kg. Its content may be higher in some
shrubs and trees, especially in areas of arid climate. Local conditions have an important impact on Ba in plants, which is illustrated by various contents, for example,
blueberries sampled in Russia contain Ba at the range 8–60 mg/kg, whereas those
sampled in Germany contain at the range 32–181 mg/kg (Markert and Vtorova 1995).
Mean Ba concentration in food plants is as follows (in mg/kg): wheat grain, 3.2;
cereal grain, 5.5; carrot, 13; tomato, 2.1; and apple, 1.5.
High Ba content (about 2000 mg/kg) inhibited the growth of some plants. Addition of Ca and S compounds reduces the Ba toxicity, possible due to the formation of
slightly soluble BaCO 3 and BaSO 4 .
4.6 HUMANS
Amount of Ba found in the human body (average 70 kg) is 22 mg, of which in the
blood 70 μg/L, in bones 3–70 mg/kg, in other tissues 0.1 mg/kg (Emsley 2011), and
in the rib bone 2.5 mg/kg (Zaichik et al. 2011).
Barium is primarily distributed to the bone and teeth; it is not known if Ba distributed to these tissues would result in toxicity. However, there are no data correlating
Ba levels in tissues and fluids with exposure levels (ATSDR 2007a).
Humans are exposed to Ba from a variety of sources such as the environment, where
it naturally occurs; drinking water; and the diet. It may also be absorbed in working
places, as it is used in many industrial applications. After absorption, Ba accumulates
in the skeleton; an accumulation also takes place in the pigmented parts of the eye.
Toxicity of Ba compounds depends on their solubility. In humans, ingestion of high
levels of soluble Ba compounds may cause gastroenteritis (vomiting, diarrhea, and
abdominal pain), hypopotassemia, hypertension, cardiac arrhythmias, and skeletal
muscle paralysis. The free ion is readily absorbed from the lung or gastrointestinal tract.
Oral absorption of soluble Ba 2+ is highly variable, in both animals and humans.
There is evidence that gastrointestinal absorption of Ba in humans is in the range
3%–60% of the administered dose, although higher spotted values are also reported.