DESIGNATIONS
CAS No.: 7440-39-3
Registry name: Barium
Chemical name: Barium
Synonyms, Trade names: Barium
Chemical name (German): Barium
Chemical name (French): Baryum
Appearance: soft, silvery white metal
BASIC CHEMICAL AND PHYSICAL DATA
Chemical symbol: Ba
Rel. atomic mass.: 137.34 g
Density: 3.51 g/cm3 at 20°C
Boiling point: 1,640°C
Melting point: 725°C
Vapour pressure: 0.13 Pa at 547°CFlash point: flammable and highly reactive solid. Contact with water (e.g. humidity) causes a strong reaction forming explosive mixtures of hydrogen gas and air. On heating, it readily reacts with oxygen and nitrogen.
Solvolysis/solubility: in water (at 20°C): reaction to barium hydroxide 32.8 g/l, barium sulphate 0.02 g/l
BASIC DATA OF SELECTED COMPOUNDS
CAS No: | 513-77-9 | 10361-37-2 |
Chemical name: | Barium carbonate | Barium chloride |
Synonyms, Trade names: | Witherite | |
Chemical name (German): | Bariumcarbonat | Bariumchlorid |
Chemical name (French): | Carbonate de baryum | Chlorure de baryum |
Appearance: | white, fine crystalline powder | colourless crystals |
Empirical formula: | BaCO3 | BaCl2 |
Rel. molecular mass: | 197.35 g | 208.25 g |
Density: | 4.29 g/cm3 | 3.91 g/cm3 |
Melting point: | 1360°C (loss of CO2) | 962°C |
Solvolysis/solubility: | in water: 2 x 10-3 wt% at 20°C | in water: 26.3 wt% at 20°C 36.6 wt% at 100°C |
ORIGIN AND USE
Usage:
Metallic Ba and Ba/Al-alloys are mainly used as scavengers to
remove the last traces of unwanted gases from vacuum tubes.
Roughly 80 % of barium sulphate is used to increase the
density of drilling fluids when drilling for oil. The remaining
20 % is used as fillers for paints and paper, as heavy
concrete additives and X-ray contrast medium as well as for
fireworks or explosives. Barium carbonate is used in the ceramics
and glass industry as well as to combat rodents in agriculture. A
further important application is the electrolysis of alkali-metal
chlorides.
Origin/derivation:
Ba is an element which is found as a mineral component (heavy
spa: barium sulphate) and makes up 0.04-0.05 % of the
Earth's crust.
Production figures:
The consumption of barium sulphate in the Federal Republic of
Germany in 1975 was about 370,000 t (DVGW, 1985).
Estimated production of BaSO4 (in 1,000 tons, 1982):
USA | 1,800 |
Western Europe | 1,030 |
Mid/Far East | 1,890 |
South Africa | 800 |
Comecon | 820 |
World | 7,250 |
Toxicity
Mammals: | ||
Rat: | LD 500 mg/kg, oral (barium acetate) | acc. DVGW, 1985 |
LD 630 mg/kg, oral (barium carbonate) | acc. DVGW, 1985 | |
LD50 150 mg/kg, oral (barium chloride) | acc. DVGW, 1985 | |
LD50 355 mg/kg, oral (barium nitrate) | acc. DVGW, 1985 | |
Mouse: | LD50 800 mg/kg, oral (barium carbonate) | acc. DVGW, 1985 |
LD 7-14 mg/kg, oral (barium chloride) | acc. DVGW, 1985 | |
Rabbit: | LD 236 mg/kg, oral (barium acetate) | acc. DVGW, 1985 |
LD 170-300 mg/kg, oral (barium carbonate) | acc. DVGW, 1985 | |
Aquatic organisms: | ||
Water flea: | 83 mg/l critical level | acc. DVGW, 1985 |
Eel: | LD 2,000 mg/l (36 h) | acc. DVGW, 1985 |
Goldfish | LD 9,400 mg/l (14.5 h) | acc. DVGW, 1985 |
Characteristic effects:
Humans/mammals: All soluble barium compounds are poisonous and readily resorbed in the gastro-intestinal tract and subsequently accumulated in the bones. The intake of between 2 and 4 g of barium chloride can prove fatal; barium ions paralyse the heart.
Acute poisoning results in nausea and diarrhoea, cardiac problems and muscular spasms as well as cardiac arrest or apnoea.
Whereas barium hydroxide is highly caustic since it forms soluble barium hydroxide in water, barium sulphate is not hazardous on account of the fact that it is virtually insoluble in water.
ENVIRONMENTAL BEHAVIOUR
Barium compounds mostly impact the environment as a result of industrial waste water. As little as 0.1 mg/l of barium is sufficient to damage micro-organisms; the self-purification capability of surface and groundwater is inhibited from 1 g/l.
ENVIRONMENTAL STANDARDS
Medium/acceptor | Sector | Country/organ. | Status |
Value | Cat. | Remarks | Source |
Water: | Surface | EC | (L) |
0.1 mg/l | 1) | acc. DVGW, 1985 | |
Surface | EC | (L) |
1 mg/l | 2) | acc. DVGW, 1985 | ||
Drinkw | AUS | 1 mg/l | 1973 | acc. MERIAN, 1984 | |||
Drinkw | CDN | 1 mg/l | 1978 | acc. DVGW, 1985 | |||
Drinkw | EC | (G) |
0.1 mg/l | Approx. figure | acc. DVGW, 1985 | ||
Drinkw | SU | 4 mg/l | 1970 | acc. MERIAN, 1984 | |||
Drinkw | USA | L |
1 mg/l | acc. DVGW, 1985 | |||
Groundw | NL | G |
50 µg/l | Reference | acc. TERRA TECH, 6/94 | ||
Groundw | NL | L |
625 µg/l | Intervention | acc. TERRA TECH, 6/94 | ||
Trough | USA | (L) |
1 mg/l | 1968 | acc. DVGW, 1985 | ||
Soil: | NL | G |
200 mg/kg | Reference | acc. TERRA TECH, 6/94 | ||
NL | L |
625 mg/kg | Intervention | acc. TERRA TECH, 6/94 | |||
Air: | Workp | AUS | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | ||
Workp | B | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | |||
Workp | CH | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | |||
Workp | D | L |
0.5 mg/m3 | MAK | DFG, 1989 | ||
Workp | DDR | (L) |
0.5 mg/m3 | MAK | acc. MERIAN, 1984 | ||
Workp | NL | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | |||
Workp | PL | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | |||
Workp | RO | (L) |
0.5 mg/m3 | Short-time value | acc. MERIAN, 1984 | ||
Workp | SF | (L) |
0.5 mg/m3 | acc. MERIAN, 1984 | |||
Workp | USA | (L) |
0.5 mg/m3 | TWA | ACGIH, 1986 | ||
Emiss. | D | L |
0,1 mg/m3 | find dust mass flow > 0.5 g/h | acc. TA Luft, 1986 | ||
Foodstuffs: | D | G |
0.5-3 mg/kg.d | ADI | acc. DVGW, 1985 | ||
Drinkw | D | L |
1 mg/l | acc. DVGW, 1985 |
Note:
There is almost a total ban in the Federal Republic of Germany on
the use of barium in cosmetics.
1) Mandatory value for simple physical treatment and
sterilisation
2) Mandatory value for normal physical and chemical
treatment and sterilisation; mandatory value for physical and
refined chemical treatment, oxidation, adsorption and
sterilisation
3) With mass flow of 1 kg/h and more
Comparison/reference values
Surface water | |||
Lake Constance (1983) | D | 23.5 µg/l | acc. DVGW, 1985 |
Ruhr (Duisburg, 1983) | D | 41 µg/l | acc. DVGW, 1985 |
Denver (1966) | USA | 16-56 µg/l | acc. DVGW, 1985 |
Drinking water | |||
100 communities | USA | 2-380 µg/l | acc. DVGW, 1985 |
Assessment/comments
Barium compounds are poisonous and highly toxic particularly to aquatic organisms. There is no possibility of comprehensive assessment since there are scarcely any data available regarding the environmental behaviour of such compounds.