The main water soluble salts are the:
The main insoluble salts are the:
- Rodenticide, insecticide, fungicide
- Manufacture of glass
- Manufacture of ceramics
- Vulcanization of synthetic rubber
- Production of pigments
- Manufacture of electronic components
- Manufacture of detergents for lubricating oils
- Purification of industrial waters
- Industry of painting
- Industry of paper
- In pottery
- Coating of welding electrodes
- Surface treatment in the metallurgical industry
- Barium sulphide is used in the production of certain types
of fluorescent tubes
- Barium sulphate is used in medical radiology and in the manufacture
of white pigments (litophone)
1 - Environmental:
Barium naturally occurs at low concentrations in ambient air,
usually < 0.05 µg/m3, but is found at relatively high
concentrations in soils , nearly 500 mg/kg. In fresh surface
water, concentrations may vary from < 5 to 15,000 µg/L.
and it contributes to water hardness. Foodstuffs provide also
barium and the daily human intake has been estimated to be in
the order of 1 mg.
2 - Industrial:
The pulmonary route of entry is the most significant in the
industrial setting (see exposure limit recommendations).
Routes of entry:
Soluble barium salts are well absorbed by pulmonary and oral
routes of entry.
Insoluble salts inhaled and deposited are eliminated only slowly
and can accumulate in the lungs as a result of long - term exposure.
Barium compounds are not reputed to penetrate by skin unless
the cutaneous barrier is broken as in chemical burns; a case
has been described in the relevant medical literature which
had been caused by barium chloride in fusion.
1 - Solubility:
The toxicity of barium salts is related largely to their solubility,
which conditions their digestive absorption and bioavailability.
Water and acid soluble salts are very toxic when ingested.
The carbonate BaCO3 is insoluble in water at neutral pH, it
becomes soluble in acid environments, which is not without consequence
in vivo because of the gastric pH. There would be under this
condition, production of barium chloride BaCl2 from the solubilized
carbonate; barium chloride is one the most toxic of soluble
2 - Metabolism:
The biological half - life of barium varies between 2 and 20
hours. Absorbed barium is mainly deposited in bones, which accounts
for 93% of the body burden in man. It is mainly excreted in
feces and a small part (1 to 10%) in urine.
3 - Exprimental toxicity:
In the case of barium carbonate, the Lethal Dose Fifty (LD50)
- mouse (ingestion): 200 mg/kg,
- rat (ingestion): 418 mg/kg,
which makes it a very toxic chemical by ingestion.
Barium stimulates the striated and cardiac muscles. This hyperstimulation
causes arrhythmias, myoclonus, digestive disorders and arterial
hypertension by direct effect on the smooth muscles of the arterial
wall independently of the renin - angiotensin system and catecolamines.
4 - Acute intoxication by ingestion:
The lethal dose in man varies, according to barium compounds
involved, between 1 and 15 g. by ingestion. Acute intoxications
are rare and generally due to suicidal attempts with the chloride
or the carbonate.
Some cases of collective food intoxications were reported,
related to food contamination, and to confusion between carbonate
and barium sulphate at the time of radiological examinations.
Barium carbonate having been substituted accidentally for potato
flour during the preparation of sausages, 144 people were poisoned
in Israel in 1963. Two patients died.
A - Clinical findings:
At the beginning, there are digestive disorders:
- diarrhoea, sometimes hemorrhagic,
- severe abdominal pain,
- nausea and vomiting.
Initially there is intense asthenia, sometimes accompanied
- muscle cramps,
- muscular contractures.
Later there is:
- gradually increasing flaccid paralysis involving the 4 limbs,
the diaphragm, and the pharyngolaryngeal junction, which often
requires to resort to artificial ventilation.
- the clinical picture may mimick a rapidly evolving Guillain
- Barré’s syndrome
- respiratory disorders and rhabdomyolysis were reported.
Cardiac symptoms and clinical signs dominate the prognosis:
- Initially there can be arterial hypertension sometimes followed
by hypotension due to digestive liquid losses (diarrhoea, vomiting).
- Disorders of excitability and conduction,
- Ventricular tachycardia,
- Torsades de pointes (« twisting of the points »)
leading sometimes to an unexpected ventricular fibrillation
responsible for the fatal types of the intoxication.
Renal complications were reported in an exceptional manner:
- Acute kidney failure with preserved diuresis,
- Opacification of kidneys due to barium precipitation.
Death occurs by respiratory failure or ventricular fibrillation.
B - Laboratory findings:
- Biological examinations highlight disorders related to water
loss caused by diarrhoea.
- Hypokaliemia (low levels of blood potassium) sometimes very
significant with acidosis, is characteristic of the intoxication.
However, initially it can be masked by respiratory acidosis.
- Electrocardiographic changes reflect cardiac effects
- When the blood concentration of barium was measured in the
course of acute intoxications, values greater than 100 µg/L
were observed. However, blood concentrations fall quickly during
the first 48 hours to become again lower than 10µg/L.
- As renal clearance of barium is rapid, the duration of the
intoxication lasts 2 to 4 days.
C - Treatment:
It comprises usual symptomatic measures:
- Gastric lavage, rehydration and correction of hydroelectrolytic
- Oral magnesium sulphate (Epsom salt) or sodium sulphate makes
it possible to precipitate soluble barium salts present in the
digestive tract as barium sulphate (insoluble).
Perfusion of the same salts by intravenous route could cause
renal complications, by intratubular precipitation of barium.
- Perfusion of important amounts of potassium is often necessary
to correct hypokaliemia mainly due to disorders of potassium
membrane transfer, which are corrected only by the elimination
of circulating barium.
- Treatment of cardiac disorders is symptomatic.
5 - Pulmonary effects:
Handling of pulverulent barium sulphate was accompanied, at
the time of already old observations, by benign pneumonias generally
resulting in pulmonary radiological images consisting of nodules
disseminated in both lung fields without clinical symptoms,
nor anomalies of respiratory functional tests, it is barytosis.
It also occurs during significant exposures to lithophone and
On the other hand, serious fibrosis was reported among workers
of barium mines because of the presence of crystaline silica
in the ore.
6 - Local effects:
Aqueous solutions of barium hydroxide and oxide are strongly
alkaline and can cause significant ocular burns and skin irritation.
The carbonate and the sulphate of barium are irritating to the
mucous membranes of the upper airways, the carbonate can also
be irritating to the skin and the eyes.
Barium chromate(VI) is the only compound recognized as carcinogenic
Barium chloride dihydrate was not mutagenic in Salmonella typhimurium,
nor did it induce sister chromatid exchanges or chromosomal
aberrations in cultured Chinese hamster ovary cells.
In a mating trial, no adverse anatomical effects were observed
in the offspring of rats or mice receiving up to 4000 ppm barium
chloride dihydrate in the drinking water, although rat pup weight
In rats and mice receiving up to 4000 ppm barium chloride dihydrate
in the drinking water, reproductive indices were unaffected.
Exposure limit recommendations:
The TLV - TWA (ACGIH) for soluble barium salts is 0.5 mg/m3.
The TLV for barium sulphate dust (insoluble) is 10 mg/m3.
Good housekeeping of your studio is important as for any other
Avoidance of processes generating unnecessary dust is also important.
Depending on the severity of exposure, local ventilation should
be used and the aspired air should be vented outside to avoid
producing dust from work tables and the floor.
Very effective filter masks should be worn if the severity
of exposure justifies it during preparation of glazes and clays.
It should be forbidden to drink, eat or smoke in the workshop.
Especially, one should not confuse barium carbonate with table
sugar when preparing coffee.
An electrocardiogram is recommended as part of the periodical
examination of workers exposed to soluble salts. Periodical
urinary and blood mesurements could also be carried out; in
subjects not professionally exposed blood concentrations are
lower than 10 µg/L, and lower than 20µg/L in the
1 - Chemical Hazards of the Workplace, Proctor & Hughes,
2 - Clinical Environmental Health and Toxic Exposures, Sullivan
3 - Encyclopédie Médico - Chirurgicale, Toxicologie
- Pathologie Professionnelle,
Pr. S. Dally, Paris, Juillet 2001.
4 - Occupational & Environmental Medicine, Ladou J., last
5 - Occupational Medicine, Zenz C., last edition.
6 - Répertoire Toxicologique de la Commission de la Santé
et Sécurité du Travail du Québec.
7 - Sax’s Dangerous Properties of Industrial Materials, Lewis
C., last edition.
8 - Toxicologie Industrielle et Intoxications Professionnelles,
Lauwerys R. last edition.